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Solid oxide fuel cells (SOFCs) are highly efficient and environmentally friendly power sources that convert chemical energy directly into electricity and heat, without the need for combustion. Despite their many benefits, the performance and durability of SOFCs heavily depend on the quality of their porous anode and cathode components. There are significant challenges with regard to their commercialization due to the potential failure and degradation of their anode and cathode components. Optimizing SOFC electrodes requires obtaining critical microstructure parameters and understanding their impact on the overall performance. This can be achieved through advanced tomography techniques and fully coupled Multiphysics simulations, which provide insights into the quality of the electrode and the complex electrochemical processes that occur within it. In this thesis, experiments were conducted to investigate different anode microstructure impacts on SOFC performance through electrochemical analysis. Besides, 2D microstructure tomography was obtained to construct real 3D volumes. Based on the tomography information, the porosity and tortuosity of the porous electrode were calculated and compared. Different tortuosity calculation methods were compared to obtain values used for Multiphysics simulations. A fully coupled Multiphysics model was constructed step by step. Firstly, the electrochemical kinetic models are compared based on the Butler-Volmer equations. Secondly, different diffusion models are compared with and without Knudsen diffusion. Based on the 3D Multiphysics CFD model, the microstructure parameters' impact on the SOFC performance was studied. Meanwhile, a SOFC model based on different sealant materials was constructed to investigate the overall thermal stress distribution. Thermal stress at an electrode/electrolyte interface was also modelled and analyzed. The results showed that the interface contact mode and the geometry size of the SOFC component significa

The construction of high-efficiency and low-cost non-noble metal bifunctional electrocatalysts for water electrolysis is crucial for commercial large-scale application of hydrogen energy. Here, we report a novel strategy with erbium-doped NiCoP nanowire arrays in situ grown on conductive nickel foam (Er-NiCoP/NF). Significantly, the developed electrode shows exceptional bifunctional catalytic activity, which only requires overpotentials of 46 and 225 mV to afford a current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Density functional theory calculations reveal that the appropriate Er incorporation into the NiCoP lattice can significantly modulate the electronic structure with the d-band centers of Ni and Co atoms by shifting to lower energies with respect to the Fermi level, and optimize the Gibbs free energies of HER/OER intermediates, thereby accelerating water-splitting kinetics. When assembled as a solar-driven overall water-splitting electrolyzer, the as-prepared electrode shows a high and stable solar-to-hydrogen efficiency of 19.6%, indicating its potential for practical storage of intermittent energy.

Foam-like NiMo coatings were produced from an inexpensive mixture of Ni, Al, and Mo powders via atmospheric plasma spraying. The coatings were deposited onto stainless-steel meshes forming a highly porous network mainly composed of nanostructured Ni and highly active Ni4Mo. High material loading (200 mg cm−2) with large surface area (1769 cm2 per cm2) was achieved without compromising the foam-like characteristics. The coatings exhibited excellent activity towards both hydrogen evolution (HER) and oxygen evolution (OER) reactions in alkaline media. The HER active coating required an overpotential of 42 mV to reach a current density of −50 mA cm−2 with minimum degradation after a 24 h chronoamperometry test at −10 mA cm−2. Theoretical simulations showed that several crystal surfaces of Ni4Mo exhibit near optimum hydrogen adsorption energies and improved water dissociation that benefit the HER activity. The OER active coating also consisting of nanostructured Ni and Ni4Mo required only 310 mV to achieve a current density of 50 mA cm−2. The OER activity was maintained even after 48 h of continuous operation. We envisage that the development of scalable production techniques for Ni4Mo alloys will greatly benefit its usage in commercial alkaline water electrolysers.

Inexpensive, high-activity bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are imperative for the development of energy storage and conversion systems. A nitrogen-doped carbon material with a micro−meso−macroporous structure doped with La (LaPNC) containing La−O/N−C active sites is prepared using SiO2 particle templating of carbon and a metal node exchange strategy. The coordination environment of La sites stabilized by two oxygen and four nitrogen atoms (LaO2N4), is further verified by X-ray absorption spectroscopy. The ORR half-wave potential reaches 0.852 V, and the OER overpotential reaches 263 mV at 10 mA cm−2. The Zn−air battery, with LaPNC as the air cathode, has a maximum power density of 202 mW cm−2 and achieves stable charge−discharge for at least 100 h without a significant increase or decrease in the charge or discharge voltages, respectively. Density functional theory calculations suggest that LaO2N4 sites exhibit the lowest activation free energy and the most easily desorbed oxygen capacity. This study provides new insights into the design of efficient, durable bifunctional catalysts as alternatives to precious-metal-based catalysts.

Most particles in the atmosphere take up water when exposed to increasing relative humidity (RH), and this behavior is described and quantized by a hygroscopicity parameter, kappa. Hygroscopic Tandem Differential Mobility Analysis (HTDMA) can be used to measure the physicochemical properties of aerosol particles and study phenomena that lead to size changes in submicron aerosol particles. Specifically, HTDMA measures how aerosol particles of different initial dry sizes grow or shrink when exposed to changing RH. HTDMA uses two differential mobility analyzers (DMAs) and a humidification system to make these measurements. One DMA selects a narrow size range of dry aerosol particles which are exposed to varying RH conditions. The second humidified DMA scans the particle size distribution after the particles have been conditioned by the humidification system. Scanning a wide range of particle sizes enables the second DMA to measure changes in size or growth factor (growth factor = humidified size/dry size) due to water uptake by the particles. The kappa can then be calculated from the growth factor. A new HTDMA system was designed for a set of RH conditions with user-friendly data-analyzing software. The software can determine the theoretical distribution of dry particles and accurately captures multiple peaks even when two peaks are close in diameter. The designed HTDMA system was calibrated by pure ammonium sulfate, a well-characterized salt that can be used to calibrate these systems. The hygroscopic behavior of a few pure amino acids and aerosol mixtures of amino acids and ammonium sulfate was investigated.

This is partial fulfillment of a dissertation defense on electrochemical detection of Arsenic (As) in water using gold (Au) nanofilms as sensing electrodes. The maximum contaminant level of Arsenic in drinking water is set at 10 g L-1 by the WHO and USEPA. Electrochemical detection by linear stripping voltammetry has comparable detection limits to more expensive laboratory-based methods but with added benefits of being portable and manufacturable. The work has developed sputtered and crystallographically oriented nanofilms for detection of trace As (III). Ultraflat Au(111) oriented thin films, Au(UTF), were compared to single crystal model electrodes to identify the impacts of controlled surface atom geometry during fundamental electrochemistry studies. We found that the Au(111) surface structure had the highest sensitivity and selectivity for As (III) detection and the Au(UTF) performed very similar to the Au(111) single crystal model electrode for detection of As (III). The Au(UTF)s were then tested to determine the ability to detect trace As when its primary competing contaminant, Cu (II), was also present. Experiments with As & Cu mixtures provided evidence of an intermetallic alloy which had a large impact on the ability to detect trace As at the Au(UTF) surface. This study has implications for manufacturable and low Au loading sensing electrodes. The work is intended to increase availability of high sensitivity detection of As in drinking water for rural areas where mining legacies and groundwater usage have resulted in increased exposure to As (III).

The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here, it is demonstrated that the disruption of the circadian rhythm by genetic deletion of mouse brain and muscle ARNT-like 1 (Bmal1) gene, coding for the key clock transcription factor, augments an exacerbated fibrotic phenotype in various tumors. Accretion of cancer-associated fibroblasts (CAFs), especially the alpha smooth muscle actin positive myoCAFs, accelerates tumor growth rates and metastatic potentials. Mechanistically, deletion of Bmal1 abrogates expression of its transcriptionally targeted plasminogen activator inhibitor-1 (PAI-1). Consequently, decreased levels of PAI-1 in the tumor microenvironment instigate plasmin activation through upregulation of tissue plasminogen activator and urokinase plasminogen activator. The activated plasmin converts latent TGF-beta into its activated form, which potently induces tumor fibrosis and the transition of CAFs into myoCAFs, the latter promoting cancer metastasis. Pharmacological inhibition of the TGF-beta signaling largely ablates the metastatic potentials of colorectal cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. Together, these data provide novel mechanistic insights into disruption of the circadian clock in tumor growth and metastasis. It is reasonably speculated that normalization of the circadian rhythm in patients provides a novel paradigm for cancer therapy., Funding Agencies|European Research Council (ERC) advanced grant ANGIOFAT [250021]; Swedish Research Council; Swedish Cancer Foundation; Swedish Childrens Cancer Foundation; Strategic Research Areas (SFO)-Stem Cell and Regenerative Medicine Foundation; Karolinska Institute Foundation; Karolinska Institute distinguished professor award; Torsten Soderbergs Foundation; Maud and Birger Gustavsson Foundation; NOVO Nordisk Foundation-Advance grant; NOVO Nordisk Foundation; Knut and Alice Wallenbergs Foundation; Robert Lundberg Memorial Foundation [2021-00668]; National Key R & D Program of China [2020YFC0846600]; Volkswagen Stiftung

Organic electrolytes are widely used in energy storage technologies, but they are known to have safety, cost, and eco friendliness concerns. Water based electrolytes do not have those issues but are limited by their narrow range potential range of operation to 1.2V. Above that voltage, significant side reactions lead to gas evolution, side reaction and high selfdischarge rate in organic batteries. Because of their superior ionic conductivities, which are critical for reducing device resistance and improving power; as well as their cost-effective ness and non-flammability, researchers have had a second look at water-based electrolyte and found out that super concentrated aqueous solutions behave differently, and their electrochemical stability window can be widened. In this thesis, polyacrylate (PAAK) based "water in polymer salt" electrolyte (WIPSE) has been identified as a promising solution for large-scale energy storage devices. This new family of "water in salt" electrolytes offers a broad electrochemical stability window of up to 3V, a high ionic conductivity (100 mS/cm) and is non-flammable, making it ideal for high power electrochemical storage devices. However, little is known about the matter transport in PAAK based WIPSE and in "water in salt" electrolytes in general. Therefore, this thesis also aims to investigate the properties of PAAK using spectroscopic techniques such as Raman spectroscopy and diffusion NMR to understand the behavior of water and the mechanism of ionic transport in relation to water and polymer chain dynamics. Since the electrolyte only transports cations, it is suitable for use in "cation rocking chair" batteries that utilize two types of polymeric quinones, lignin, and polyimide redox polymers, as positive and negative electrodes, respectively. The electrochemically active redox polymers with K+ ions at neutral pH are ions at neutral pH are advantageous for avoiding corrosion in metal collectors. Further for understanding the fundam, Organiska elektrolyter används i stor utsträckning i energilagringstekniker, mende är kända för att ha problem med säkerhet, kostnad och miljövänlighet. Vattenbaserade elektrolyter har inte dessa problem utan begränsas av deras smala potentialområde för drift till 1.2 V. Över den spänningen leder betydande sidoreaktioner till gasutveckling, sidoreaktion och hög självurladdningshastighet i organiska batterier. På grund av deras överlägsna jonledningsförmåga, som är avgörande för att minska enhetens motstånd och förbättra kraften; och u töver deras kostnadseffektivitet och icke antändlighet har forskare tagit en andra titt på vattenbaserad elektrolyt och upptäckt att superkoncentrerade vattenlösningar beter sig annorlunda och att deras elektrokemiska stabilitetsfönster kan vidgas. I denna avhandling har polyakrylat (PAAK) baserad "vatten i polymersalt" elektrolyt (WIPSE) identifierats som en lovande lösning för storskaliga energilagringsenheter. Denna nya familj av "vatten i salt" elektrolyter erbjuder ett brett elektrokemiskt stabilitetsfönster på upp till 3V, en hög jonledningsförmåga (100 mS/cm) och är icke brandfarlig, vilket gör den idealisk för högeffekts elektrokemiska lagringsenheter. Lite är dock känt om materia transporten i PAAK baserade WIPSE och i "vatten i salt" elektrolyter i allmänhet. Därför syftar denna avhandling också till att undersöka egenskaperna hos PAAK med hjälp av spektroskopiska tekniker såsom Raman spektroskopi och diffusions NMR för att förstå vattnets beteende och mekanismen för jontransport i relation till vatten och polymerkedjedynamik. Eftersom elektrolyten endast transporterar katjoner är den lämplig för användning i "katjongungstols" batterier som använder två typer av polymera kinoner, lignin och polyimid redoxpolymerer, som positiva respektive negativa elektroder. De elektrokemiskt aktiva redox polymererna med K+ -joner vid neutralt pH är fördelaktiga för at t undvika korrosion i metallsamlare. För att ytterligare förstå grunden f

The interfacial energetics are known to play a crucial role in organic diodes, transistors, and sensors. Designing the metal-organic interface has been a tool to optimize the performance of organic (opto)electronic devices, but this is not reported for organic thermoelectrics. In this work, it is demonstrated that the electrical power of organic thermoelectric generators (OTEGs) is also strongly dependent on the metal-organic interfacial energetics. Without changing the thermoelectric figure of merit (ZT) of polythiophene-based conducting polymers, the generated power of an OTEG can vary by three orders of magnitude simply by tuning the work function of the metal contact to reach above 1000 mu W cm(-2). The effective Seebeck coefficient (S-eff) of a metal/polymer/metal single leg OTEG includes an interfacial contribution (V-inter/Delta T) in addition to the intrinsic bulk Seebeck coefficient of the polythiophenes, such that S-eff = S + V-inter/Delta T varies from 22.7 mu V K-1 [9.4 mu V K-1] with Al to 50.5 mu V K-1 [26.3 mu V K-1] with Pt for poly(3,4-ethylenedioxythiophene):p-toluenesulfonate [poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)]. Spectroscopic techniques are used to reveal a redox interfacial reaction affecting locally the doping level of the polymer at the vicinity of the metal-organic interface and conclude that the energetics at the metal-polymer interface provides a new strategy to enhance the performance of OTEGs., Funding Agencies|Knut and Alice Wallenberg Foundation; EU [ESR 955837_HORATES]; Swedish Research Council [2016-06146, 2016-03979]; Forsk [18-313]; Academy of Finland Postdoctoral Researcher [340103]; EU H2020 Marie Sklodowska-Curie [101022777]; Swedish Foundation for Strategic Research (SiOS); Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoeping University [2009-00971]

Artificial muscles, or soft actuators, that could exhibit contractile stroke and operate in open-air, would be crucial for many applications, such as robotics, prosthetics, or powered exoskeletons. Amongst the different artificial muscle technologies, electrochemical carbon nanotube (CNT) yarn muscles, transducing capacitively ionic accumulation at the electrochemical double layer into linear contraction, are amongst the most promising candidates. However, their performances are either limited by an undesired bipolar behaviour or short lifetime due to the inevitable drying of water-based electrolytes. In this paper, we present here the fabrication of air -operating contractile linear artificial muscles from commercially available CNT yarns exhibiting outstanding performance. The synthesis and the junction of two ionogels based on cationic and anionic polyelectrolyte have been designed for the coating process on CNT yarns, and for selectively orienting the ionic flow allowing optimal electromechanical energy conversion. The dual-electrode CNT yarn actuators showed air-stable unipolar con-tractile stroke, reaching 9.7% without loss of performances after 2000 cycles., Funding Agencies|European Union [825232]; Conseil regional ile de France [:15013107]

To facilitate the shift from fossil to renewable energy sources, energy storage is needed to cope with the intermittent nature of technologies such as solar, wind, and wave power. One storage alternative is battery-based stationary energy storage. There are many battery types to choose from, but Nickel Metal Hydride (NiMH) is a type that is especially well suited. These batteries have a high energy density, a large temperature operating window and are a safe alternative for large scale energy storage. In this thesis, the behavior of the NiMH battery is studied with the aim to develop a dynamic battery model, a model that is capable of reproducing the battery voltage and pressure, also for dynamic usage. Such a model can be used to facilitate development of NiMH batteries, improvement of the algorithms used in the Battery Management System (BMS), quality control, and dimensioning of energy storage systems. These improvements can lead to stationary energy storage with a higher efficiency and longer usable lifetime. To increase the understanding of the battery function, deeper study was carried out of two behaviors that are typical for the NiMH battery and are deemed to have a large impact on the battery: Open circuit voltage (OCV) hysteresis and the battery gas phase behavior. The OCV hysteresis complicates modelling because it causes the battery rest voltage at a certain degree of charge to depend on the charge/discharge path taken to get there. OCV hysteresis is not noticeable for all batteries, and it is especially prominent for the NiMH battery. The gas phase in the NiMH battery is active since the electrolyte is water based and the voltage window during operation causes oxygen evolution at the positive electrode. The oxygen is then recombined into water at the negative electrode. The amount of hydrogen in the gas phase varies over a cycle due to the the dependence on temperature and state of charge of the hydrogen equilibrium pressure over the negative metal hydr, För att underlätta skiftet från fossilbaserade till förnyelsebara energikällor behövs energilagring för att hantera den intermittenta produktionen hos tekniker som sol- vind och vågkraft. Ett alternativ är stationär energilagring med hjälp av batterier. Det finns många batterityper att välja på, men Nickel Metallhydrid batterier (NiMH) är särskilt lämpade. De har bra energidensitet, stort temperaturfönster och är ett säkert alternativ för storskalig energilagring. I den här avhandlingen studeras NiMH batteriets beteende med målet att ta fram en dynamisk batterimodell, en modell som är kapabel att reproducera batteriets spänning och tryckbeteende även för dynamiska körcykler. En sådan modell kan avvändas till att underlätta utveckling av NiMH batterier, förbättra algoritmerna i batteriernas styrsystem, kvalitetskontroll och dimensionering av system. I förlängningen innebär det stationära energilager med högre verkningsgrad och längre livslängd. För att öka förståelsen för hur batteriet fungerar så har fördjupning gjorts i två beteenden som är typiska för NiMH batteriet och ansågs ha särskilt stor inverkan: Öppetkretsspänningshysteresen och beteendet hos batteriets gasfas. Öppetkretsspänningshysteresen försvårar modellering genom att batteriets vilospänning vid en viss laddningsgrad beror på hur det laddats och laddats ur för att komma dit. Öppetkretsspänningshysteres är inte någonting som är märkbart hos alla batterityper, men den är särskilt kraftig hos NiMH. Gasfasen hos batteriet är aktiv eftersom elektrolyten är vattenbaserad och dess spänningsfönster vid drift orsakar syrgasutveckling på den positiva elektroden. Syrgasen återbildas sedan till vatten på den negativa elektroden. Mängden vätgas i gasfasen förändras pågrund av hur jämviktstrycket av vätgas över den negativa vätelagringselektroden beror av laddningsgrad och temperatur. I arbetet så utvecklades två modeller separat för att beskriva dessa två beteenden. Modellerna visade upp en god kvalitativ överenst, QC 20231027

Organic electrolytes are widely used in energy storage technologies, but they are known to have safety, cost, and eco friendliness concerns. Water based electrolytes do not have those issues but are limited by their narrow range potential range of operation to 1.2V. Above that voltage, significant side reactions lead to gas evolution, side reaction and high selfdischarge rate in organic batteries. Because of their superior ionic conductivities, which are critical for reducing device resistance and improving power; as well as their cost-effective ness and non-flammability, researchers have had a second look at water-based electrolyte and found out that super concentrated aqueous solutions behave differently, and their electrochemical stability window can be widened. In this thesis, polyacrylate (PAAK) based "water in polymer salt" electrolyte (WIPSE) has been identified as a promising solution for large-scale energy storage devices. This new family of "water in salt" electrolytes offers a broad electrochemical stability window of up to 3V, a high ionic conductivity (100 mS/cm) and is non-flammable, making it ideal for high power electrochemical storage devices. However, little is known about the matter transport in PAAK based WIPSE and in "water in salt" electrolytes in general. Therefore, this thesis also aims to investigate the properties of PAAK using spectroscopic techniques such as Raman spectroscopy and diffusion NMR to understand the behavior of water and the mechanism of ionic transport in relation to water and polymer chain dynamics. Since the electrolyte only transports cations, it is suitable for use in "cation rocking chair" batteries that utilize two types of polymeric quinones, lignin, and polyimide redox polymers, as positive and negative electrodes, respectively. The electrochemically active redox polymers with K+ ions at neutral pH are ions at neutral pH are advantageous for avoiding corrosion in metal collectors. Further for understanding the fundam, Organiska elektrolyter används i stor utsträckning i energilagringstekniker, mende är kända för att ha problem med säkerhet, kostnad och miljövänlighet. Vattenbaserade elektrolyter har inte dessa problem utan begränsas av deras smala potentialområde för drift till 1.2 V. Över den spänningen leder betydande sidoreaktioner till gasutveckling, sidoreaktion och hög självurladdningshastighet i organiska batterier. På grund av deras överlägsna jonledningsförmåga, som är avgörande för att minska enhetens motstånd och förbättra kraften; och u töver deras kostnadseffektivitet och icke antändlighet har forskare tagit en andra titt på vattenbaserad elektrolyt och upptäckt att superkoncentrerade vattenlösningar beter sig annorlunda och att deras elektrokemiska stabilitetsfönster kan vidgas. I denna avhandling har polyakrylat (PAAK) baserad "vatten i polymersalt" elektrolyt (WIPSE) identifierats som en lovande lösning för storskaliga energilagringsenheter. Denna nya familj av "vatten i salt" elektrolyter erbjuder ett brett elektrokemiskt stabilitetsfönster på upp till 3V, en hög jonledningsförmåga (100 mS/cm) och är icke brandfarlig, vilket gör den idealisk för högeffekts elektrokemiska lagringsenheter. Lite är dock känt om materia transporten i PAAK baserade WIPSE och i "vatten i salt" elektrolyter i allmänhet. Därför syftar denna avhandling också till att undersöka egenskaperna hos PAAK med hjälp av spektroskopiska tekniker såsom Raman spektroskopi och diffusions NMR för att förstå vattnets beteende och mekanismen för jontransport i relation till vatten och polymerkedjedynamik. Eftersom elektrolyten endast transporterar katjoner är den lämplig för användning i "katjongungstols" batterier som använder två typer av polymera kinoner, lignin och polyimid redoxpolymerer, som positiva respektive negativa elektroder. De elektrokemiskt aktiva redox polymererna med K+ -joner vid neutralt pH är fördelaktiga för at t undvika korrosion i metallsamlare. För att ytterligare förstå grunden f

Elanvändningen i Sverige förväntas fördubblas till 2045 på grund av ökad elektrifiering av det svenska samhället. För att ställa om till ett elsystem som är beroende av mer förnyelsebara elproduktionsslag föreslår Svenska kraftnät (2021) att Sverige kommer att behöva öka sin flexibilitet i elnätet. Ett sätt att göra detta på är genom ellagring, där batterisystem är ett alternativ. Någon konkret plan för hur och när detta skulle genomföras har inte gjorts av Svenska kraftnät. Därför syftade detta projekt till att ta reda på om ett litiumjärnfosfat (LFP) batterienergilagringssystem skulle vara en lönsam investering att använda för energiomställning i det svenska elmarknadsområdet SE3. Detta mål uppnåddes genom att modellera ett batterilager över ett år och extrapolera dessa resultat till en investeringskalkyl genom annuitetsmetoden. Sammanfattat så konstaterades det att det inte är en lönsam investering. Men det fullständiga svaret är mer komplicerat än så. Batteriets storlek och livslängd påverkar batteriets investeringskostnad, som vidare påverkar batteriets lönsamhet. Batteriets livslängd är beroende av egenskaper som batteriets upp och urladdningstid (s.k. C-rate) samt i vilken utsträckning batteriet laddas och laddas ur (s.k. state of charge), som i sin tur influerar totala antalet laddningscykler batteriet kan genomföra. Exakt hur mycket dessa egenskaper påverkar livslängden för LFP:erna är oklart eftersom resultaten från tidigare studier av LFP-batteriers prestanda skiljer sig något. Till exempel är det känt att state of charge för ett batteri påverkar livslängden för ett LFP-batteri, men mer exakt hur mycket varierar beroende på studie, vilket visas i detta examensarbete. Det som gör detta ännu mer komplicerat är det faktum att investeringskostnaden kommer att förändras beroende på till exempel vilken state of charge som används. Dessutom varierar uppskattningar av investeringskostnaden för LFP-batterier i olika källor. Allt detta leder till flera typer av osä, The electricity use in Sweden is expected to double before 2045 due to increased electrification of the Swedish society. In order to transition into an electrical system that is dependent of more sustainable renewable energy sources, Svenska kraftnät (2021) is suggesting that Sweden will need to increase their flexibility in the power grid. One of the main ideas on how to do that is through energy storages, where battery systems could play an important part. However, a concrete plan of how and when this would happen was not made clear by Svenska kraftnät. Therefore, this project aimed at finding out whether a Lithium iron phosphate (LFP) battery energy storage system would be a worthwhile investment to use for energy shifting in the Swedish SE3 electricity market area. This aim was reached through modelling a battery storage over a year and extrapolating these results into an investment calculation using the annuity method. In short, it was found that it is not a profitable investment. But the full answer was found to be more complicated than that. The battery’s size and lifetime affect the battery’s investment cost, which further affects the battery’s profitability. The battery’s lifetime is dependent on battery characteristics such as the charge/discharge time of the battery (C-rate) and the extent to which the battery is charged and discharged (state of charge), which in turn influences the total amount of charge cycles a battery can perform. Further, how significant these characteristics affect cost and lifetime of the LFP’s is unclear as the results from previous studies on LFP batteries differ somewhat. For example, it is known that the state of charge range of a battery affects the lifetime of an LFP battery, but by exactly how much varies with different studies, which is explained in this master thesis. What makes this even more complicated is the fact that depending on the state of charge used, the investment cost will change. Additionally, the assessed inv

I det här examensarbetet har utvecklingen av den svenska politiken kring biodrivmedel under perioden 1975–2020 undersökts. Detta i syfte att öka förståelsen för de politiska motiv som legat till grund vid utformningen av politiska styrmedel samt hur sambanden mellan styrmedel och biodrivmedelsproduktion utvecklats. I rapporten ingår granskningen av de propositioner och underlagsrapporter som varit grund till svenska styrmedel riktade mot biodrivmedel. Styrmedelsförslagen har beskrivits och vissa skillnader mellan underlagsrapporter och slutgiltigt förslag har diskuterats. De motiveringar och politiska mål som hänvisas till i styrmedelsförslagen har satts i en bredare kontext för att beskriva hur utvecklingen sett ut. Utvecklingen av biodrivmedelsmarknaden har samtidigt undersökts med hjälp av Energimyndighetens årliga rapporter samt årsredovisningar och offentliga uttalanden från de största biodrivmedelsproducenterna. Vad denna genomgång visat är att biodrivmedel använts som ett medel för att minska användningen av fossilbaserad bensin och diesel för att nå målen inom ett flertal olika politikområden. I början av tidsperioden var det främsta målet att öka den svenska energiförsörjningstryggheten, det målet kompletterades sedan med mål om att minska hälso- och miljöskadliga utsläpp. Att minska utsläppen av växthusgaser började sedan bli allt mer prioriterat och har under de senaste 20–30 åren varit det främsta målet. Vilka målsättningar som biodrivmedel kopplats till har skiftat under tidperioden och det har även funnits skillnader mellan olika styrmedel under samma tidsperiod. Forsknings- och utvecklingsstöd har varit fokuserade på att omvandla inhemska råvaror till biodrivmedel. Finansiella- och administrativa styrmedel har i stället främst varit utformade för att öka andelen biodrivmedel i den totala mängden drivmedel och inte för att öka den inhemska produktionen. Efter Sveriges inträde i EU har en stor del av den svenska biodrivmedelspolitiken varit utformad til, In this thesis, the development of Swedish biofuel policy during the period 1975–2020 were investigated. The goal was to increase the understanding of the political motives behind the formulation of policy instruments and how the links between policy instruments and biofuel production have developed. A review of policy instruments targeting biofuels were conducted and presented in the report. The basis for the policy proposals has been summarized and some differences between the suggested policy and the final proposal have been discussed. The justifications and policy objectives referred to in the proposals have been put in a broader context to describe the development. The development of the biofuel market was investigated using the reports compiled annually by the Swedish Energy Agency, as well as previous compilations from several journals. What these reviews have shown is that biofuels have been used as a means of reducing the use of fossil-based petrol and diesel to achieve the targets in several different policy areas. At the beginning of the period, the main goal was to increase Swedish energy security, which was then supplemented by the goal of reducing harmful emissions. Reducing greenhouse gas emissions then became an increasing priority and has over the past 20–30 years been the main goal. The objectives to which biofuels have been linked have both changed during the period, and there have also been d¬ifferences between different policy instruments during the same period. Research and development support have been focused on converting domestic raw materials into biofuels, while financial and administrative instruments have mainly been designed to increase the share of biofuel use within the total use of transportation fuels and not to increase domestic production. Since Sweden's entry into the EU, a large part of the Swedish biofuels policy has been designed to comply with the EU directives that have existed. The policy instruments that have existed have

The pursuit of reliable and high-performance batteries has fueled extensive research into new battery chemistries and materials, aiming to enhance the current lithium-ion battery technologies in terms of energy density and safety. Among the potential advancements, solid-state batteries (SSBs) have captured significant attention as the next-generation energy storage technology. One key factor contributing to their appeal is the utilization of solid-state electrolytes (SSEs) with a wide electrochemical stability window (ESW), making SSBs compatible with high-voltage cathodes. The energy density of SSBs can be further improved by employing the “holy-grail” anode, Li-metal, which boasts the lowest working voltage (-3.04 V vs. Li+/Li) and an ultrahigh theoretical capacity (3860 mAh g−1). Consequently, these batteries are referred to as lithium metal batteries (LMBs). However, realizing the full potential of LMBs presents formidable challenge, including the low ionic conductivity of current SSEs, large interfacial resistance between SSE and electrodes, uncontrollable interfacial reactions, and the growth of Li dendrites. Typically, SSEs can be categorized into three types. Among these, solid composite electrolytes (SCEs) are considered the most promising choice for solid-state LMBs due to their combination of high ionic conductivity and excellent mechanical strength from inorganic solid electrolytes (ISEs) and the flexibility and good interface compatibility provided by solid polymer electrolytes (SPEs). Polymeric ionic liquids (PolyILs), which contain both ionic liquid-like moieties and polymer frameworks, have emerged as highly attractive alternatives to traditional polymers in SCEs. The overall objective of this thesis was to develop PolyIL-based SCEs with enhanced ionic conductivity, wide ESW, high Li+ transference number, and reduced electrodes/electrolyte interface resistance. The main progress achieved in this thesis is as follows: 1. We selected three F-based Li

Terahertz (THz) technologies provide opportunities ranging from calibration targets for satellites and telescopes to communication devices and biomedical imaging systems. A main component will be broadband THz absorbers with switchability. However, optically switchable materials in THz are scarce and their modulation is mostly available at narrow bandwidths. Realizing materials with large and broadband modulation in absorption or transmission forms a critical challenge. This study demonstrates that conducting polymer-cellulose aerogels can provide modulation of broadband THz light with large modulation range from approximate to 13% to 91% absolute transmission, while maintaining specular reflection loss < -30 dB. The exceptional THz modulation is associated with the anomalous optical conductivity peak of conducting polymers, which enhances the absorption in its oxidized state. The study also demonstrates the possibility to reduce the surface hydrophilicity by simple chemical modifications, and shows that broadband absorption of the aerogels at optical frequencies enables de-frosting by solar-induced heating. These low-cost, aqueous solution-processable, sustainable, and bio-friendly aerogels may find use in next-generation intelligent THz devices., Funding Agencies|Swedish Research Council(VR); Swedish Foundation for Strategic Research (SSF); Stellenbosch Institute for Advanced Study (STIAS); Swedish Foundation for International Cooperation in Research and Higher Education (STINT); Knut and Alice Wallenberg Foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkping University [61831012]; National Natural Science Foundation of China (NFSC) [62131006, 52003202, 2023YFB381130005, 2021JDTD0026, 2023JDGD0012]; National Key Research and Development Program of China [2019-252]; Sichuan Province Science and Technology Support Program [2020-00287, 2022-00211]; Guangdong Science and Technology Major Special Fund [2022-06214]; Wallenberg Wood Science Center; [2009 00971]; [62311530115]; [62235004]

The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here, it is demonstrated that the disruption of the circadian rhythm by genetic deletion of mouse brain and muscle ARNT-like 1 (Bmal1) gene, coding for the key clock transcription factor, augments an exacerbated fibrotic phenotype in various tumors. Accretion of cancer-associated fibroblasts (CAFs), especially the alpha smooth muscle actin positive myoCAFs, accelerates tumor growth rates and metastatic potentials. Mechanistically, deletion of Bmal1 abrogates expression of its transcriptionally targeted plasminogen activator inhibitor-1 (PAI-1). Consequently, decreased levels of PAI-1 in the tumor microenvironment instigate plasmin activation through upregulation of tissue plasminogen activator and urokinase plasminogen activator. The activated plasmin converts latent TGF-beta into its activated form, which potently induces tumor fibrosis and the transition of CAFs into myoCAFs, the latter promoting cancer metastasis. Pharmacological inhibition of the TGF-beta signaling largely ablates the metastatic potentials of colorectal cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. Together, these data provide novel mechanistic insights into disruption of the circadian clock in tumor growth and metastasis. It is reasonably speculated that normalization of the circadian rhythm in patients provides a novel paradigm for cancer therapy., Funding Agencies|European Research Council (ERC) advanced grant ANGIOFAT [250021]; Swedish Research Council; Swedish Cancer Foundation; Swedish Childrens Cancer Foundation; Strategic Research Areas (SFO)-Stem Cell and Regenerative Medicine Foundation; Karolinska Institute Foundation; Karolinska Institute distinguished professor award; Torsten Soderbergs Foundation; Maud and Birger Gustavsson Foundation; NOVO Nordisk Foundation-Advance grant; NOVO Nordisk Foundation; Knut and Alice Wallenbergs Foundation; Robert Lundberg Memorial Foundation [2021-00668]; National Key R & D Program of China [2020YFC0846600]; Volkswagen Stiftung

Organic electrolytes are widely used in energy storage technologies, but they are known to have safety, cost, and eco friendliness concerns. Water based electrolytes do not have those issues but are limited by their narrow range potential range of operation to 1.2V. Above that voltage, significant side reactions lead to gas evolution, side reaction and high selfdischarge rate in organic batteries. Because of their superior ionic conductivities, which are critical for reducing device resistance and improving power; as well as their cost-effective ness and non-flammability, researchers have had a second look at water-based electrolyte and found out that super concentrated aqueous solutions behave differently, and their electrochemical stability window can be widened. In this thesis, polyacrylate (PAAK) based "water in polymer salt" electrolyte (WIPSE) has been identified as a promising solution for large-scale energy storage devices. This new family of "water in salt" electrolytes offers a broad electrochemical stability window of up to 3V, a high ionic conductivity (100 mS/cm) and is non-flammable, making it ideal for high power electrochemical storage devices. However, little is known about the matter transport in PAAK based WIPSE and in "water in salt" electrolytes in general. Therefore, this thesis also aims to investigate the properties of PAAK using spectroscopic techniques such as Raman spectroscopy and diffusion NMR to understand the behavior of water and the mechanism of ionic transport in relation to water and polymer chain dynamics. Since the electrolyte only transports cations, it is suitable for use in "cation rocking chair" batteries that utilize two types of polymeric quinones, lignin, and polyimide redox polymers, as positive and negative electrodes, respectively. The electrochemically active redox polymers with K+ ions at neutral pH are ions at neutral pH are advantageous for avoiding corrosion in metal collectors. Further for understanding the fundam, Organiska elektrolyter används i stor utsträckning i energilagringstekniker, mende är kända för att ha problem med säkerhet, kostnad och miljövänlighet. Vattenbaserade elektrolyter har inte dessa problem utan begränsas av deras smala potentialområde för drift till 1.2 V. Över den spänningen leder betydande sidoreaktioner till gasutveckling, sidoreaktion och hög självurladdningshastighet i organiska batterier. På grund av deras överlägsna jonledningsförmåga, som är avgörande för att minska enhetens motstånd och förbättra kraften; och u töver deras kostnadseffektivitet och icke antändlighet har forskare tagit en andra titt på vattenbaserad elektrolyt och upptäckt att superkoncentrerade vattenlösningar beter sig annorlunda och att deras elektrokemiska stabilitetsfönster kan vidgas. I denna avhandling har polyakrylat (PAAK) baserad "vatten i polymersalt" elektrolyt (WIPSE) identifierats som en lovande lösning för storskaliga energilagringsenheter. Denna nya familj av "vatten i salt" elektrolyter erbjuder ett brett elektrokemiskt stabilitetsfönster på upp till 3V, en hög jonledningsförmåga (100 mS/cm) och är icke brandfarlig, vilket gör den idealisk för högeffekts elektrokemiska lagringsenheter. Lite är dock känt om materia transporten i PAAK baserade WIPSE och i "vatten i salt" elektrolyter i allmänhet. Därför syftar denna avhandling också till att undersöka egenskaperna hos PAAK med hjälp av spektroskopiska tekniker såsom Raman spektroskopi och diffusions NMR för att förstå vattnets beteende och mekanismen för jontransport i relation till vatten och polymerkedjedynamik. Eftersom elektrolyten endast transporterar katjoner är den lämplig för användning i "katjongungstols" batterier som använder två typer av polymera kinoner, lignin och polyimid redoxpolymerer, som positiva respektive negativa elektroder. De elektrokemiskt aktiva redox polymererna med K+ -joner vid neutralt pH är fördelaktiga för at t undvika korrosion i metallsamlare. För att ytterligare förstå grunden f

Electrically tunable metasurfaces and interrelated nanofabrication techniques are essential for metasurface-based optoelectronic applications. We present a nanofabrication method suitable for various types of plasmonic polymer metasurfaces including inverted arrays of nanoantennas. Inverted metasurfaces are of particular interest since the metasurface itself can work as an electrode due to its interconnected nature, which enables electrical control without adopting an additional electrode. In comparison with inverted nanodisk arrays that support relatively weak resonance features, we show that inverted nanorod arrays can possess stronger resonances, even comparable with those of nanorod arrays. The origin of plasmon resonances in inverted arrays is systematically investigated using finite-difference time-domain (FDTD) simulations. Further, we demonstrate electrically tunable electrode-free metasurface devices using polymer inverted nanorod arrays, which can operate in the full spectral range of the material including the mid-infrared region. Electrically tunable and electrode-free metasurfaces using plasmonic polymer inverted nanoantenna arrays can operate across the entire spectral range of the material, including the mid-infrared region., Funding Agencies|National Research Foundation of Korea (NRF) grant [2020R1A2C1102558, 2019R1C1C1006681]; Institute of Information & communications Technology Planning & Evaluation (IITP) grant [2022-0-00897]; Nano.Material Technology Development Program [2009-0082580]; Commercialization Promotion Agency for R&D Outcomes (COMPA) (Research Equipment Technician Training Program) - Korea government (MSIT) [2023-23020001-10]; AForsk Foundation [20367]; Knut and Alice Wallenberg Foundation; Swedish Research Council (VR) [2020-00287, 2022-00211]; Swedish Foundation for Strategic Research (SSF); Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]

The synthesis of NH3 via electrochemical N2 fixation at ambient conditions has been proposed as a promising alternative to the traditional Haber-Bosch process. However, the development of highly efficient and selective electrocatalysts remains a challenge. In this study, uniform Ag@AgP2 @Ni-CoP@C core-shell nanowires were synthesized using a template-engaged strategy. The merging of conductive Ag core with active AgP2 and porous carbon-coated Ni-doped CoP shells favors the mass and electron transfers, effectively lowering the activation energy toward the reduction of N2 to NH3. Density functional theory (DFT) calculations further indicates that the sandwiched AgP2 layer plays crucial roles in promoting electrocatalytic kinetics and suppressing the competitive hydrogen evolution reactions. Benefiting from these advantages, the titled catalyst achieved a high NH3 yield of 16.84 & mu;g h-1 mg-1 cat. at-0.4 V (vs. reversible hydrogen electrode, RHE) and a high Faradaic efficiency of 21.7 % at-0.3 V vs. RHE, as well as high electrochemical and structure stability., Funding Agencies|National Natural Science Foundation of China [21010500300]; Science and Technology Innovation Plan of Shanghai Science and Technology Commission [[2020] 1Y043]; Guizhou Provincial Science and Technology Foundation [CH2017-7243]; STINT Joint China -Sweden Mobility Project [2009 0097]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University; [12275168]

The metal-free carbon-based catalyst with low cost and high oxygen reduction reaction (ORR) activity is urgently desired to satisfy the demands of microbial fuel cells (MFCs). However, it is still a great challenge to develop a facile and feasible strategy to construct efficient active sites of heteroatom doping for carbon-based electrocatalyst. Herein, we report a strategy based on an ammonium fluoride (NH4F) gas-steamed metal-organic frameworks (MOFs) to heighten structural defects and density of N, F active sites of metal-free catalyst. Oxygen temperature-programmed deposition and density functional theory results confirm that the NH4F gas-steamed process greatly enhances the adsorption affinity of O2 and oxygen intermediates on the catalysts. The resulted N and F co-doped porous carbon cage (FNC-15) demonstrates outstanding ORR catalytic activity and long-term stability in alkaline and neutral electrolytes. This work proposes a facile and efficient in situ gas-steamed strategy to develop metal-free cathode catalysts with superior performance., Funding Agencies|National Natural Science Foundation of China [51778156]; Pearl River S amp; T Nova Program of Guangzhou [201806010191]; Science and Technology Program of Guangzhou [201707010256]; Talent Cultivation Program of Guangzhou Uni-versity; Guangdong Natural Science Foundation [2022A1515010441]

Lithium-ion battery degradation is complex, and many mechanisms occur concurrently. In-depth degradation is traditionally investigated by post-mortem characterization in lab-settings. If mechanisms could instead be identified in-operando, utilization could be adjusted, and battery lifetime extended. We investigate changes in electrochemical model parameters during battery testing and their correlation with degradation observed in a traditional post-mortem characterization. Commercial batteries are cycle-aged using different stationary storage service cycles and a novel reference performance test is applied intermittently. This test is based on current profiles optimally designed with respect to maximized sensitivity for individual electrochemical parameters and embedded within a charging procedure. Usage dependency of parameter trajectories over the course of ageing is demonstrated and coupled to observed micro-structural changes. Subsequently, the parameter trajectories are extrapolated using Gaussian Process Regression for physics-based state-of-health estimation and remaininguseful-life prediction. We demonstrate and validate estimation of full cell performance under constant load at a later state in life.

Anodic dissolution (often referred to as corrosion) of the aluminum positive electrode current collector above 3 V vs. Li+/Li can become performance-limiting in high-voltage Li-ion batteries. Herein, the results of a systematic reevaluation of this phenomenon at potentials up to 5.0 V vs. Li+/Li, using different carbonate electrolytes containing LiPF6, LiFSI or LiTFSI, are presented. The anodic dissolution is most likely caused by etching of the Al2O3 passive layer by protons released during the oxidation of the solvent. This sparks off a second oxidation step, involving the oxidation of the aluminum. While a passive AlF3 layer is formed in 1.0 M LiPF6, extensive anodic dissolution of aluminum is seen in 1.0 M LiFSI or LiTFSI at potentials where the solvent undergoes oxidation. In 5.0 M LiFSI, a passive layer of AlF3 is, however, formed most likely due to the presence of fluoride as an impurity in the LiFSI. No significant improvement was seen when using carbon-coated aluminum electrodes.

Sulfur hexafluoride (SF6) is a highly potent greenhouse gas (GHG) that is mainly emitted from high-voltage electrical applications. The global warming potential (GWP) of the gas is almost 23 000 times that of CO2 and therefore, controlling its emission and recovery is of great importance from both an environmental and economic perspective. Solid adsorbents and adsorption-based technology is a cost-effective and energy-efficient pathway to recapture SF6 from its sources, which usually consist of dilute SF6 in N2. Here, we present a group of four highly porous and robust gallium- or vanadium-based metal–organic frameworks (MOFs) with exceptional SF6 uptake and selectivity. In particular, the novel gallium 1,2,4,5-tetrakis(4-carboxlatephenyl)benzene (TCPB4−) MOF (Ga-TBAPy) possesses 1-dimensional channels of suitable size (5.2 × 8.4 Å and 5.3 × 10 Å) to adsorb up to 2.25 mmol g−1 of SF6 at 10 kPa with an excellent SF6-over-N2 selectivity of 418. Ga-TCPB also exhibits high chemical stability in aqueous and acidic media as well as in organic solvents. 3D electron diffraction (3D ED) patterns combined with high-resolution electron microscopy images were employed to investigate the structure of these water-stable and cyclable MOF SF6 adsorbents. Furthermore, this study demonstrates the possibility of using these highly stable MOFs to capture SF6 from a gas mixture as well as how MOFs can offer an alternative and efficient way to mitigate the global warming contributions from the emission of SF6.

Artificial muscles, or soft actuators, that could exhibit contractile stroke and operate in open-air, would be crucial for many applications, such as robotics, prosthetics, or powered exoskeletons. Amongst the different artificial muscle technologies, electrochemical carbon nanotube (CNT) yarn muscles, transducing capacitively ionic accumulation at the electrochemical double layer into linear contraction, are amongst the most promising candidates. However, their performances are either limited by an undesired bipolar behaviour or short lifetime due to the inevitable drying of water-based electrolytes. In this paper, we present here the fabrication of air -operating contractile linear artificial muscles from commercially available CNT yarns exhibiting outstanding performance. The synthesis and the junction of two ionogels based on cationic and anionic polyelectrolyte have been designed for the coating process on CNT yarns, and for selectively orienting the ionic flow allowing optimal electromechanical energy conversion. The dual-electrode CNT yarn actuators showed air-stable unipolar con-tractile stroke, reaching 9.7% without loss of performances after 2000 cycles., Funding Agencies|European Union [825232]; Conseil regional ile de France [:15013107]

The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here, it is demonstrated that the disruption of the circadian rhythm by genetic deletion of mouse brain and muscle ARNT-like 1 (Bmal1) gene, coding for the key clock transcription factor, augments an exacerbated fibrotic phenotype in various tumors. Accretion of cancer-associated fibroblasts (CAFs), especially the alpha smooth muscle actin positive myoCAFs, accelerates tumor growth rates and metastatic potentials. Mechanistically, deletion of Bmal1 abrogates expression of its transcriptionally targeted plasminogen activator inhibitor-1 (PAI-1). Consequently, decreased levels of PAI-1 in the tumor microenvironment instigate plasmin activation through upregulation of tissue plasminogen activator and urokinase plasminogen activator. The activated plasmin converts latent TGF-beta into its activated form, which potently induces tumor fibrosis and the transition of CAFs into myoCAFs, the latter promoting cancer metastasis. Pharmacological inhibition of the TGF-beta signaling largely ablates the metastatic potentials of colorectal cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. Together, these data provide novel mechanistic insights into disruption of the circadian clock in tumor growth and metastasis. It is reasonably speculated that normalization of the circadian rhythm in patients provides a novel paradigm for cancer therapy., Funding Agencies|European Research Council (ERC) advanced grant ANGIOFAT [250021]; Swedish Research Council; Swedish Cancer Foundation; Swedish Childrens Cancer Foundation; Strategic Research Areas (SFO)-Stem Cell and Regenerative Medicine Foundation; Karolinska Institute Foundation; Karolinska Institute distinguished professor award; Torsten Soderbergs Foundation; Maud and Birger Gustavsson Foundation; NOVO Nordisk Foundation-Advance grant; NOVO Nordisk Foundation; Knut and Alice Wallenbergs Foundation; Robert Lundberg Memorial Foundation [2021-00668]; National Key R & D Program of China [2020YFC0846600]; Volkswagen Stiftung

Organic electrolytes are widely used in energy storage technologies, but they are known to have safety, cost, and eco friendliness concerns. Water based electrolytes do not have those issues but are limited by their narrow range potential range of operation to 1.2V. Above that voltage, significant side reactions lead to gas evolution, side reaction and high selfdischarge rate in organic batteries. Because of their superior ionic conductivities, which are critical for reducing device resistance and improving power; as well as their cost-effective ness and non-flammability, researchers have had a second look at water-based electrolyte and found out that super concentrated aqueous solutions behave differently, and their electrochemical stability window can be widened. In this thesis, polyacrylate (PAAK) based "water in polymer salt" electrolyte (WIPSE) has been identified as a promising solution for large-scale energy storage devices. This new family of "water in salt" electrolytes offers a broad electrochemical stability window of up to 3V, a high ionic conductivity (100 mS/cm) and is non-flammable, making it ideal for high power electrochemical storage devices. However, little is known about the matter transport in PAAK based WIPSE and in "water in salt" electrolytes in general. Therefore, this thesis also aims to investigate the properties of PAAK using spectroscopic techniques such as Raman spectroscopy and diffusion NMR to understand the behavior of water and the mechanism of ionic transport in relation to water and polymer chain dynamics. Since the electrolyte only transports cations, it is suitable for use in "cation rocking chair" batteries that utilize two types of polymeric quinones, lignin, and polyimide redox polymers, as positive and negative electrodes, respectively. The electrochemically active redox polymers with K+ ions at neutral pH are ions at neutral pH are advantageous for avoiding corrosion in metal collectors. Further for understanding the fundam, Organiska elektrolyter används i stor utsträckning i energilagringstekniker, mende är kända för att ha problem med säkerhet, kostnad och miljövänlighet. Vattenbaserade elektrolyter har inte dessa problem utan begränsas av deras smala potentialområde för drift till 1.2 V. Över den spänningen leder betydande sidoreaktioner till gasutveckling, sidoreaktion och hög självurladdningshastighet i organiska batterier. På grund av deras överlägsna jonledningsförmåga, som är avgörande för att minska enhetens motstånd och förbättra kraften; och u töver deras kostnadseffektivitet och icke antändlighet har forskare tagit en andra titt på vattenbaserad elektrolyt och upptäckt att superkoncentrerade vattenlösningar beter sig annorlunda och att deras elektrokemiska stabilitetsfönster kan vidgas. I denna avhandling har polyakrylat (PAAK) baserad "vatten i polymersalt" elektrolyt (WIPSE) identifierats som en lovande lösning för storskaliga energilagringsenheter. Denna nya familj av "vatten i salt" elektrolyter erbjuder ett brett elektrokemiskt stabilitetsfönster på upp till 3V, en hög jonledningsförmåga (100 mS/cm) och är icke brandfarlig, vilket gör den idealisk för högeffekts elektrokemiska lagringsenheter. Lite är dock känt om materia transporten i PAAK baserade WIPSE och i "vatten i salt" elektrolyter i allmänhet. Därför syftar denna avhandling också till att undersöka egenskaperna hos PAAK med hjälp av spektroskopiska tekniker såsom Raman spektroskopi och diffusions NMR för att förstå vattnets beteende och mekanismen för jontransport i relation till vatten och polymerkedjedynamik. Eftersom elektrolyten endast transporterar katjoner är den lämplig för användning i "katjongungstols" batterier som använder två typer av polymera kinoner, lignin och polyimid redoxpolymerer, som positiva respektive negativa elektroder. De elektrokemiskt aktiva redox polymererna med K+ -joner vid neutralt pH är fördelaktiga för at t undvika korrosion i metallsamlare. För att ytterligare förstå grunden f

The interfacial energetics are known to play a crucial role in organic diodes, transistors, and sensors. Designing the metal-organic interface has been a tool to optimize the performance of organic (opto)electronic devices, but this is not reported for organic thermoelectrics. In this work, it is demonstrated that the electrical power of organic thermoelectric generators (OTEGs) is also strongly dependent on the metal-organic interfacial energetics. Without changing the thermoelectric figure of merit (ZT) of polythiophene-based conducting polymers, the generated power of an OTEG can vary by three orders of magnitude simply by tuning the work function of the metal contact to reach above 1000 mu W cm(-2). The effective Seebeck coefficient (S-eff) of a metal/polymer/metal single leg OTEG includes an interfacial contribution (V-inter/Delta T) in addition to the intrinsic bulk Seebeck coefficient of the polythiophenes, such that S-eff = S + V-inter/Delta T varies from 22.7 mu V K-1 [9.4 mu V K-1] with Al to 50.5 mu V K-1 [26.3 mu V K-1] with Pt for poly(3,4-ethylenedioxythiophene):p-toluenesulfonate [poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)]. Spectroscopic techniques are used to reveal a redox interfacial reaction affecting locally the doping level of the polymer at the vicinity of the metal-organic interface and conclude that the energetics at the metal-polymer interface provides a new strategy to enhance the performance of OTEGs., Funding Agencies|Knut and Alice Wallenberg Foundation; EU [ESR 955837_HORATES]; Swedish Research Council [2016-06146, 2016-03979]; Forsk [18-313]; Academy of Finland Postdoctoral Researcher [340103]; EU H2020 Marie Sklodowska-Curie [101022777]; Swedish Foundation for Strategic Research (SiOS); Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoeping University [2009-00971]

Lithium-ion battery degradation is complex, and many mechanisms occur concurrently. In-depth degradation is traditionally investigated by post-mortem characterization in lab-settings. If mechanisms could instead be identified in-operando, utilization could be adjusted, and battery lifetime extended. We investigate changes in electrochemical model parameters during battery testing and their correlation with degradation observed in a traditional post-mortem characterization. Commercial batteries are cycle-aged using different stationary storage service cycles and a novel reference performance test is applied intermittently. This test is based on current profiles optimally designed with respect to maximized sensitivity for individual electrochemical parameters and embedded within a charging procedure. Usage dependency of parameter trajectories over the course of ageing is demonstrated and coupled to observed micro-structural changes. Subsequently, the parameter trajectories are extrapolated using Gaussian Process Regression for physics-based state-of-health estimation and remaininguseful-life prediction. We demonstrate and validate estimation of full cell performance under constant load at a later state in life.

Sulfur hexafluoride (SF6) is a highly potent greenhouse gas (GHG) that is mainly emitted from high-voltage electrical applications. The global warming potential (GWP) of the gas is almost 23 000 times that of CO2 and therefore, controlling its emission and recovery is of great importance from both an environmental and economic perspective. Solid adsorbents and adsorption-based technology is a cost-effective and energy-efficient pathway to recapture SF6 from its sources, which usually consist of dilute SF6 in N2. Here, we present a group of four highly porous and robust gallium- or vanadium-based metal–organic frameworks (MOFs) with exceptional SF6 uptake and selectivity. In particular, the novel gallium 1,2,4,5-tetrakis(4-carboxlatephenyl)benzene (TCPB4−) MOF (Ga-TBAPy) possesses 1-dimensional channels of suitable size (5.2 × 8.4 Å and 5.3 × 10 Å) to adsorb up to 2.25 mmol g−1 of SF6 at 10 kPa with an excellent SF6-over-N2 selectivity of 418. Ga-TCPB also exhibits high chemical stability in aqueous and acidic media as well as in organic solvents. 3D electron diffraction (3D ED) patterns combined with high-resolution electron microscopy images were employed to investigate the structure of these water-stable and cyclable MOF SF6 adsorbents. Furthermore, this study demonstrates the possibility of using these highly stable MOFs to capture SF6 from a gas mixture as well as how MOFs can offer an alternative and efficient way to mitigate the global warming contributions from the emission of SF6.

Anodic dissolution (often referred to as corrosion) of the aluminum positive electrode current collector above 3 V vs. Li+/Li can become performance-limiting in high-voltage Li-ion batteries. Herein, the results of a systematic reevaluation of this phenomenon at potentials up to 5.0 V vs. Li+/Li, using different carbonate electrolytes containing LiPF6, LiFSI or LiTFSI, are presented. The anodic dissolution is most likely caused by etching of the Al2O3 passive layer by protons released during the oxidation of the solvent. This sparks off a second oxidation step, involving the oxidation of the aluminum. While a passive AlF3 layer is formed in 1.0 M LiPF6, extensive anodic dissolution of aluminum is seen in 1.0 M LiFSI or LiTFSI at potentials where the solvent undergoes oxidation. In 5.0 M LiFSI, a passive layer of AlF3 is, however, formed most likely due to the presence of fluoride as an impurity in the LiFSI. No significant improvement was seen when using carbon-coated aluminum electrodes.

This paper presents assessment of natural and anthropogenic sources of blue energy within Swedish territory to identify suitable spots for implementing new projects. The natural energy potential of salinity gradients was found to be higher in southwest Sweden, and a national energy resource potential of 2610.6 MW from seawater/river water mixing will be reduced to a technical potential ranging from 1044.3 MW to 1825.4 MW considering technical and environmental constraints. It has been found that the theoretical extractable energy potential in Sweden is equivalent to 13% of the total electricity consumption and 6.2% of the total final energy consumption by energy commodities. Anthropogenic water sources were also highlighted as promising low and high-concentration solutions for SGE extraction. Gotland was identified as an attractive location for generating salinity gradient power. The total salinity gradient power obtainable by mixing municipal wastewater with seawater in Sweden was estimated to be 11.8 MW. The most promising site for this process was determined to be Gryaab AB Ryaverket in Gothenburg, which accounted for 45.8% of the total national potential from anthropogenic sources.

To meet the demanding requirements for clean energy production, the need to develop advanced electrocatalysts for efficiently catalysing the water splitting reactions attracts a continuously increased attention. However, to meet the anticipated expansion in green hydrogen production from renewable energy sources, the catalysts used for the water splitting reaction not only need to satisfy the required figures of merit but should concurrently be based mainly on abundant, non-critical materials with low environmental impact. In last decades, non-noble metal catalysts, based on transition metals, rare-earth metals, dichalcogenides, and light elements such as phosphorus, nitrogen, and sulphur have shown improved performance. Moreover, in recent years increased interest has been focused on variations of such materials, more specifically on the introduction of defects to further boost their catalytic performance. Through the many studies performed over the last years, it is now possible to summarize, understand and describe the role of these defects for the water splitting reactions, namely the hydrogen and oxygen evolution reactions, and thereby to suggest strategies in the development of next generation electrocatalysts. This is the goal of the current review; we critically summarize the latest progress on the role of introduced defects for catalytic electrolysis applications by scrutinizing the structure–performance correlation as well as the specific catalytic activity. A broad class of nanomaterials is covered, comprising transition metal dichalcogenides, transition metal oxides and carbides, carbon-based materials as well as metal–organic frameworks (MOFs). Finally, the main challenges and future strategies and perspectives in this rapidly evolving field are provided at the end of the review.

Plant vasculature transports molecules that play a crucial role in plant signaling including systemic responses and acclimation to diverse environmental conditions. Targeted controlled delivery of molecules to the vascular tissue can be a biomimetic way to induce long distance responses, providing a new tool for the fundamental studies and engineering of stress-tolerant plants. Here, a flexible organic electronic ion pump, an electrophoretic delivery device, for controlled delivery of phytohormones directly in plant vascular tissue is developed. The c-OEIP is based on polyimide-coated glass capillaries that significantly enhance the mechanical robustness of these microscale devices while being minimally disruptive for the plant. The polyelectrolyte channel is based on low-cost and commercially available precursors that can be photocured with blue light, establishing much cheaper and safer system than the state-of-the-art. To trigger OEIP-induced plant response, the phytohormone abscisic acid (ABA) in the petiole of intact Arabidopsis plants is delivered. ABA is one of the main phytohormones involved in plant stress responses and induces stomata closure under drought conditions to reduce water loss and prevent wilting. The OEIP-mediated ABA delivery triggered fast and long-lasting stomata closure far away from the delivery point demonstrating systemic vascular transport of the delivered ABA, verified delivering deuterium-labeled ABA., Funding Agencies|European Union [800926 (FET-OPEN-HyPhOE)]; Swedish Foundation For Strategic Research; Swedish Foundation For Strategic Research [FFL18-0101]; Knut and Alice Wallenberg Foundation; Wallenberg Wood Science Center; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoeping University [2009-00971]; Swedish Research Council; Swedish Governmental Agency for Innovation Systems (VINNOVA)

Future brain-computer interfaces will require local and highly individualized signal processing of fully integrated electronic circuits within the nervous system and other living tissue. New devices will need to be developed that can receive data from a sensor array, process these data into meaningful information, and translate that information into a format that can be interpreted by living systems. Here, the first example of interfacing a hardware-based pattern classifier with a biological nerve is reported. The classifier implements the Widrow-Hoff learning algorithm on an array of evolvable organic electrochemical transistors (EOECTs). The EOECTs channel conductance is modulated in situ by electropolymerizing the semiconductor material within the channel, allowing for low voltage operation, high reproducibility, and an improvement in state retention by two orders of magnitude over state-of-the-art OECT devices. The organic classifier is interfaced with a biological nerve using an organic electrochemical spiking neuron to translate the classifiers output to a simulated action potential. The latter is then used to stimulate muscle contraction selectively based on the input pattern, thus paving the way for the development of adaptive neural interfaces for closed-loop therapeutic systems., Funding Agencies|Knut and Alice Wallenberg Foundation; Swedish Research Council [2018-06197, 2020-03243]; VINNOVA [2020-05223]; Swedish Foundation for Strategic Research [RMX18-0083]; European Research Council [834677]; European Commission [GA-964677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]

Following growing concerns about the effect these last decades of accelerating energy consumption, escalating use of natural (not the least fossil) resources, and waste generation has had on earth’s climate, human health, and the environment, industry is facing mounting pressure to increase the energy-, resource-, and cost-efficiency of both processes and products while drastically reducing pollutant emissions. In response, industry is, besides increasing their utilization of renewable energy and introducing new bio-based products, taking advantage of the rapid development in 5G technology and associated wireless interconnectivity to move towards full automation of production processes and facilities. With the ability to connect and collect information from a large number of instruments and process steps as well as to analyse huge amounts of multi-dimensional data, entire production lines can be automatically controlled and/or adapted, e.g., through the application of machine learning, for optimized efficiency and minimized greenhouse gas and pollutant emissions. In order to fully benefit from this so-called 4th industrial revolution and the Industrial Internet of Things (IIoT), however, access to cost-efficient and long-term reliable means for measuring various process parameters in multiple locations is required. The basis for this thesis is therefore the characterization of silicon carbide-based Metal Oxide Semiconductor Field Effect Transistor (MOSFET) gas sensors for their applicability in real-time monitoring of process gases/ gas mixtures and pollutant emissions in high-temperature applications, e.g., control of flue gas/ exhaust after-treatment systems, as well as investigations performed to gain a better understanding of the corresponding sensing mechanisms and to improve sensor performance in terms of e.g., long-term reliability. Besides demonstrating the general applicability of SiC MOSFET gas sensors in ammonia (NH3) slip detection and control of Selecti, Author's last name incorrectly spelled "Khajavizaeh" on title page

Lithium ion batteries (LIB) have become a cornerstone of the shift to electric transportation. In an attempt to decrease the production load and prolong battery life, understanding different degradation mechanisms in state-of-the-art LIBs is essential. Here, we analyze how operational temperature and state-of-charge (SoC) range in cycling influence the ageing of automotive grade 21700 batteries, extracted from a Tesla 3 long Range 2018 battery pack with positive electrode containing LiNixCoyAlzO2 (NCA) and negative electrode containing SiOx-C. In the given study we use a combination of electrochemical and material analysis to understand degradation sources in the cell. Herein we show that loss of lithium inventory is the main degradation mode in the cells, with loss of material on the negative electrode as there is a significant contributor when cycled in the low SoC range. Degradation of NCA dominates at elevated temperatures with combination of cycling to high SoC (beyond 50%)., QC 20230901

Water flows in only a small fraction of the total area of the fractures in fractured rocks. The width of the “channels” is often in the range of centimeters to tens of centimeters. Nuclides can diffuse into and out of the porous rock matrix, which causes them to be significantly retarded compared to the water velocity. In discrete facture networks, diffusion is modeled to be linear and perpendicular to the fracture surface. From a narrow channel, the diffusion cloud would then be as wide as the channel. When the nuclide has propagated farther than the channel width, the diffusion will become essentially radial, which allows the nuclide flux to increase enormously. For the times of interest for a repository for high-level nuclide waste, this will increase nuclide flux into the matrix by tens to thousands of times, and consequently, the nuclide retardation in the flowing water. Radial diffusion was not invoked in the performance assessment of the Forsmark site, which in January 2022 was chosen by the government to locate Sweden’s high-level waste repository. It is shown, using data from this site, that the effect of radial diffusion from the narrow channels considerably increases the retardation of any escaping radionuclides, potentially allowing for the use of thinner copper canisters., QC 20230626

Lithium-ion batteries have enabled vast societal changes, ranging in scale from the adoption of personal electronics to electromobility and grid-scale, renewable energy storage. However, all applications face performance fade over time, observed as losses of battery capacity and power. This gradual degradation is most often due to electrochemical aging processes inside the cell, including phenomena causing a loss of cyclable lithium (e.g., lithium plating, growth of the solid­‑electrolyte interphase or SEI), a loss of active material (e.g., particle cracking), and/or a loss of ionic or electronic conductivity. In the compiled works, many individual batteries have been aged and analyzed to better understand the conditions contributing to aging in different cell designs. The cells studied include lab-built pouch cells, commercial cylindrical cells (with electrodes LiNixMnyCo1‑x‑yO2‑LiMn2O4/C6 and LiNixCoyAl1‑x‑yO2/C6‑SiOx), and larger automotive-grade prismatic cells (LiNixMnyCo1‑x‑yO2/C6). Complementary in situ and post mortem methods are developed, with relevance for both battery research and battery control systems. Excellent characterization can often be achieved by a combination of differential voltage and incremental capacity analyses. Obtained from a simple, slow cycle, the derivatives of the voltage profile reveal many features that can be tracked over aging. This thesis particularly develops these techniques for blended electrodes, deconvoluting the aging of individual components. Dynamic performance is resolved with a novel polarization factor, impedance spectroscopy, and tools based on current pulses/interruptions. Finally, a protocol based on nuclear magnetic resonance spectroscopy is developed, enabling fast and direct quantification of lithium plating and SEI on harvested battery components. With such tools, we can improve how batteries are used and monitored, paving the way for efficient research and safer, more reliable batteries., Litiumjonbatterier har haft en stor betydelse för samhällsutvecklingen då de möjliggjort allt från bärbar elektronik till elektromobilitet och balansering av elnätet. Tyvärr tappar batterier prestanda över tid, både genom försämrad kapacitet och effekt. Den gradvisa försämringen beror främst på interna elektrokemiska processer, varav förluster av cyklingsbart litium genom plätering av litiummetall eller tillväxt av deponerade skikt av nedbrytningsmaterial, så kallat SEI-skikt, är typiska. Andra mekanismer är degradering av de elektrokemiskt aktiva materialen och/eller förluster i ledningsförmåga. Avhandlingen behandlar ett stort antal battericeller som åldrats och därefter analyserats elektrokemiskt både under och efter cyklingen. Syftet har varit att förbättra förståelsen av degradering av olika batterityper som funktion av hur de har använts. I arbetet ingår labbceller såväl som kommersiellt tillgängliga cylindriska och prismatiska celler med nickelrik cellkemi ämnade för fordons-tillämpningar. Kompletterande in situ och post mortem metoder har utvecklas med relevans såväl för forskning som för kontrollsystem för batterier. Utförlig identifiering av åldringsprocesser är möjlig med en kombination av differentiella spännings- och kapacitetsanalyser. Derivatan av en långsam upp- eller urladdningscykel ger nyttig information om åldrings-processerna som pågår. Arbetet i den här avhandlingen syftar till att förbättra metoderna särskilt gällande elektroder med fler än en aktiv komponent. Dynamiska driftegenskaper påvisades med mätningar av polarisering och impedans, samt strömpulsmetoder. Slutligen har en metodik utvecklats för att kvantitativt bestämma förekomsten av litiumplätering och SEI i post mortem analys med kärnmagnetisk resonansspektroskopi. Med dessa metoder kan vi förbättra kontrollen av batterier för att förlänga deras livslängd, vilket gynnar såväl fortsatt forskning som en säkrare och mer tillförlitlig användning av batterier i framtiden., QC 2023-05-11

The development of sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) have accelerated since they can now reach similar gravimetric energy densities as lithium-ion batteries (LIBs) but with a lower environmental impact. Hard carbon is the most common negative electrode for SIBs and KIBs and can be made from renewable resources such as lignin. Lignin can be then manufactured into fibres which can then be used as free-standing electrodes to push even further the sustainability by reducing the amount of current collector and additives needed in the battery. The concept of structural batteries is defined as a system that can simultaneously carry mechanical load as well as store the electrical energy in form of a battery to decrease the total weight. Polyacrylonitrile-based (PAN-based) carbon fibres are some of the most adapted materials thanks to their outstanding mechanical properties as well as their ability to be used as negative electrode for LIBs. However, a structural model and insertion model for alkali-ion insertion in the PAN-based carbon fibres is still lacking and is necessary to be able to understand the dynamics and fundamentals. This thesis focuses on the use of lignin-based carbon fibres (LCFs) and PAN-based carbon fibres as negative electrodes. The potential of using LCFs as negative electrode for SIBs and KIBs is evaluated by using a combination of electrochemical techniques and material characterization methods. The LCFs have high specific capacity and high initial coulombic efficiency when used as negative electrode for SIBs. The diffusion of potassium-ions into the LCFs is investigated by implementing a numerical model. The investigation on the open circuit voltage curves and the entropy change for potassium-ion insertion suggests that the LCFs structure contains two domains which can explain why the numerical model cannot fully fit the experimental data. The PAN-based carbon fibres are investigated as negative electrode for LIBs and SIBs, Utvecklingen av natriumjonbatterier (SIBs) och kaliumjonbatterier (KIBs) har tagit fart sedan deras gravimetriska energidensiteter blivit jämförbara med litiumjonbatterier, men med en lägre miljöpåverkan. Hårt kol (HC) är det vanligaste negativa elektrodmaterialet för SIBs och KIBs och kan tillverkas av biobaserade material som t.ex. lignin. Kolfibrer kan sen tillverkas från lignin som då blir fristående elektroder med en ännu lägre miljöpåverkan. Strukturella batterier är ett koncept som samtidigt kan bära mekanisk belastning och lagra energi för att minska den totala vikten av t.ex. fordon. Kolfibrer baserade på polyakrylnitril (PAN)är den bästa kandidaten för negativ elektrod för strukturella batterier eftersom de har utmärka mekaniska egenskaper och kan användas som negativ elektrod för litiumjonbatterier. En strukturell modell och inlagringsmodell saknas dock fortfarande; båda två behövs för att förstå dynamiken av hur PANbaserade kolfibrer fungerar som negativa elektroder. Denna avhandling fokuserar på användningen av ligninbaserade kolfibrer och PAN-baserade kolfibrer som negativa elektroder. Ligninbaserade kolfibrer utvärderas först som negativa elektroder för SIBs och KIBs med en kombination av elektrokemiska och materialvetenskapliga metoder. Ligninbaserade kolfibrer har en hög specifik kapacitet och hög första coulombiska verkningsgrad för SIBs. Kaliumjoners diffusionskoefficient i ligninbaserade kolfibrer bestäms med en numerisk modell. En analys av den öppna kretsspänningen och entropiändringen av kaliumjonbatterier med ligninbaserade kolfibrer tyder på att ligninbaserade kolfibrers mikrostruktur innehåller minst två olika områden som kan förklara varför den numeriska modellen inte helt kan förklara experimentella data. PAN-baserade kolfibrer analyseras som negativa elektroder för LIBs och SIBs. För SIBs analyseras den axialla expansionen genom laddning och urladdning, vilket visar en stegvis expansion mellan sluttningsregionen och platåregionen. För LI, QC 2023-05-23

Crystallization abounds in nature and industrial practice. A plethora of indispensable products ranging from agrochemicals and pharmaceuticals to battery materials are produced in crystalline form in industrial practice. Yet, our control over the crystallization process across scales, from molecular to macroscopic, is far from complete. This bottleneck not only hinders our ability to engineer the properties of crystalline products essential for maintaining our quality of life but also hampers progress toward a sustainable circular economy in resource recovery. In recent years, approaches leveraging light fields have emerged as promising alternatives to manipulate crystallization. In this review article, we classify laser-induced crystallization approaches where light-material interactions are utilized to influence crystallization phenomena according to proposed underlying mechanisms and experimental setups. We discuss nonphotochemical laser-induced nucleation, high-intensity laser-induced nucleation, laser trapping-induced crystallization, and indirect methods in detail. Throughout the review, we highlight connections among these separately evolving subfields to encourage the interdisciplinary exchange of ideas., QC 20230530

To meet the demanding requirements for clean energy production, the need to develop advanced electrocatalysts for efficiently catalysing the water splitting reactions attracts a continuously increased attention. However, to meet the anticipated expansion in green hydrogen production from renewable energy sources, the catalysts used for the water splitting reaction not only need to satisfy the required figures of merit but should concurrently be based mainly on abundant, non-critical materials with low environmental impact. In last decades, non-noble metal catalysts, based on transition metals, rare-earth metals, dichalcogenides, and light elements such as phosphorus, nitrogen, and sulphur have shown improved performance. Moreover, in recent years increased interest has been focused on variations of such materials, more specifically on the introduction of defects to further boost their catalytic performance. Through the many studies performed over the last years, it is now possible to summarize, understand and describe the role of these defects for the water splitting reactions, namely the hydrogen and oxygen evolution reactions, and thereby to suggest strategies in the development of next generation electrocatalysts. This is the goal of the current review; we critically summarize the latest progress on the role of introduced defects for catalytic electrolysis applications by scrutinizing the structure–performance correlation as well as the specific catalytic activity. A broad class of nanomaterials is covered, comprising transition metal dichalcogenides, transition metal oxides and carbides, carbon-based materials as well as metal–organic frameworks (MOFs). Finally, the main challenges and future strategies and perspectives in this rapidly evolving field are provided at the end of the review.

The realization of the membrane-free two-step water electrolysis is particularly important yet challenging for the low-cost and large-scale supply of hydrogen energy. In this effort, Co-doped Ni(OH)2 nanosheets were successfully anchored onto the nickel foam (NF) substrate through the in-situ growth of metal-organic frame material and the subsequent alkali-etching technique. Using the well-regulated Co-doping Ni(OH)2@NF electrodes as a charge mediator, electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were decoupled on time scales, thus affording a membrane-free two-step route for H2 and O2 productions. In this architecture, the first HER process on the cathode could be maintained for 1300 s at a current of 100 mA, while the corresponding Ni(OH)2 charge mediator was simultaneously oxidized to NiOOH, with a decent cell voltage of 1.542 V. The subsequent OER process involved a reduction/regeneration of Ni(OH)2 (from NiOOH to Ni(OH)2) and an anodic O2-production, with an operating voltage of 0.291 V. Moreover, the Ni-Zn battery assembled through the combination of NiOOH and Zn sheet could replace the second step of OER to achieve the coupling of continuous H2-production and battery discharge, thus also providing a new way for hydrogen production without an external power supply. Experiment and theoretical calculations have shown that the cobalt-doping not only improved the conductivity of the charge-buffer electrode, but also shifted its redox potential cathodically and boosted the adsorption affinity of the buffer medium to OH– ions, both contributing to promoted HER and OER activity. Therefore, this decoupled water electrolysis device affords a promising pathway to support the efficient conversion of renewables to hydrogen.

Inexpensive, high-activity bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are imperative for the development of energy storage and conversion systems. A nitrogen-doped carbon material with a micro−meso−macroporous structure doped with La (LaPNC) containing La−O/N−C active sites is prepared using SiO2 particle templating of carbon and a metal node exchange strategy. The coordination environment of La sites stabilized by two oxygen and four nitrogen atoms (LaO2N4), is further verified by X-ray absorption spectroscopy. The ORR half-wave potential reaches 0.852 V, and the OER overpotential reaches 263 mV at 10 mA cm−2. The Zn−air battery, with LaPNC as the air cathode, has a maximum power density of 202 mW cm−2 and achieves stable charge−discharge for at least 100 h without a significant increase or decrease in the charge or discharge voltages, respectively. Density functional theory calculations suggest that LaO2N4 sites exhibit the lowest activation free energy and the most easily desorbed oxygen capacity. This study provides new insights into the design of efficient, durable bifunctional catalysts as alternatives to precious-metal-based catalysts.

The construction of high-efficiency and low-cost non-noble metal bifunctional electrocatalysts for water electrolysis is crucial for commercial large-scale application of hydrogen energy. Here, we report a novel strategy with erbium-doped NiCoP nanowire arrays in situ grown on conductive nickel foam (Er-NiCoP/NF). Significantly, the developed electrode shows exceptional bifunctional catalytic activity, which only requires overpotentials of 46 and 225 mV to afford a current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Density functional theory calculations reveal that the appropriate Er incorporation into the NiCoP lattice can significantly modulate the electronic structure with the d-band centers of Ni and Co atoms by shifting to lower energies with respect to the Fermi level, and optimize the Gibbs free energies of HER/OER intermediates, thereby accelerating water-splitting kinetics. When assembled as a solar-driven overall water-splitting electrolyzer, the as-prepared electrode shows a high and stable solar-to-hydrogen efficiency of 19.6%, indicating its potential for practical storage of intermittent energy.

Foam-like NiMo coatings were produced from an inexpensive mixture of Ni, Al, and Mo powders via atmospheric plasma spraying. The coatings were deposited onto stainless-steel meshes forming a highly porous network mainly composed of nanostructured Ni and highly active Ni4Mo. High material loading (200 mg cm−2) with large surface area (1769 cm2 per cm2) was achieved without compromising the foam-like characteristics. The coatings exhibited excellent activity towards both hydrogen evolution (HER) and oxygen evolution (OER) reactions in alkaline media. The HER active coating required an overpotential of 42 mV to reach a current density of −50 mA cm−2 with minimum degradation after a 24 h chronoamperometry test at −10 mA cm−2. Theoretical simulations showed that several crystal surfaces of Ni4Mo exhibit near optimum hydrogen adsorption energies and improved water dissociation that benefit the HER activity. The OER active coating also consisting of nanostructured Ni and Ni4Mo required only 310 mV to achieve a current density of 50 mA cm−2. The OER activity was maintained even after 48 h of continuous operation. We envisage that the development of scalable production techniques for Ni4Mo alloys will greatly benefit its usage in commercial alkaline water electrolysers.

The advancement of bifunctional oxygen catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is imperative yet challenging for the optimization of Zn-air batteries. In this study, we reported the successful incorporation of a novel Mott-Schottky catalytic site within a MnO-FeCo heterojunction into an N-doping carbon nanobox, taking into consideration the effects of the intrinsic electric field and hollow/porous support carriers for electrocatalyst design. As expected, the resulting heterogeneous catalyst exhibited an encouraging half-wave potential of 0.88 V and an impressive limiting-current density of 5.62 mA/cm2 for the ORR, as well as a minimal overpotential of 271 mV at 10 mA/cm2 for the OER, both in alkaline conditions. Furthermore, the Zn-air battery constructed with the heterojunction nanobox product displayed a decent potential gap of 0.621 V, an outstanding power density of 253 mW/cm2, a considerable specific capacity of 761 mAh/gZn, and exceptional stability, with up to 336 h of cycling charging and discharging operation. Consequently, this method of modulating the catalyst's surface charge distribution through an internal electric field at the interface and facilitating mass transport offers a novel avenue for the development of robust bifunctional oxygen catalysts.