Search

Platinum (Pt) remains the benchmark electrocatalyst for alkaline hydrogen evolution reaction (HER), but its industry‐scale hydrogen production is severely hampered by the lack of well‐designed durable Pt‐based materials that can operate at ampere‐level current densities. Herein, based on the original oxide layer and parallel convex structure on the surface of nickel foam (NF), a 3D quasi‐parallel architecture consisting of dense Pt nanoparticles (NPs) immobilized oxygen vacancy‐rich NiOx heterojunctions (Pt/NiOx‐OV) as an alkaline HER catalyst is developed. A combined experimental and theoretical studies manifest that anchoring Pt NPs on NiOx‐OV leads to electron‐rich Pt species with altered density of states (DOS) distribution, which can efficiently optimize the d‐band center and the adsorption of reaction intermediates as well as enhance the water dissociation ability. The as‐prepared catalyst exhibits extraordinary HER performance with a low overpotential of 19.4 mV at 10 mA cm−2, a mass activity 16.3‐fold higher than that of 20% Pt/C, and a long durability of more than 100 h at 1000 mA cm−2. Furthermore, the assembled alkaline electrolyzer combined with NiFe‐layered double hydroxide requires extremely low voltage of 1.776 V to attain 1000 mA cm−2, and can operate stably for more than 400 h, which is rarely achieved. [ABSTRACT FROM AUTHOR]

Defects in nanocarbon materials can trigger their intriguing electrochemical properties and potential applications, but their synthesis is challenging. Herein, we report the synthesis of ultrathin nitrogen-doped carbon nanosheets with intrinsic defects through the pyrolysis of ZIF-8 with linker vacancies. The as-synthesized electrocatalyst exhibits excellent oxygen reduction reaction (ORR) activity with an onset potential and half-wave potential of 1.05 and 0.873 V vs. RHE, respectively, outperforming the reported metal-free ORR electrocatalysts. It also shows a commercial Pt/C-comparable performance in zinc–air battery with a power density of 154.4 mW cm−2. Characterization and DFT calculation results suggest the adjacent sp3-carbon in carbon pentagon can significantly strengthen the adsorption and activation of oxygen molecules on sp2-carbon, hence the potential determining step is altered and ORR overpotential is lowered. This work highlights a promising green synthesis strategy of MOF-derived metal-free nanocarbon materials for wide application in advanced energy technologies. [Display omitted] • Hydrothemal synthesis of ZIF-8 with linker vacancies by addition of boric acid. • Rich edge sites, carbon pentagon and sp3 hybrization in derived metal-free carbon. • Superior ORR and zinc–air battery performance among reported metal-free materials. • Synergistic effect of topological defect and hybrization state. [ABSTRACT FROM AUTHOR]

Colloidal quantum dot light‐emitting diodes (QLEDs) simultaneously exhibiting high external quantum efficiency (EQE) and operation stability are achieved via a simple solution processing. A silver bis(trifluoromethane‐sulfonyl)imide treatment that is used to chemically dope the poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) hole injection layer (HIL) is proposed. The ionic liquid salt acts as an effective p‐dopant for high charge concentrations; and it raises the work functions and surface potentials of the PEDOT:PSS HIL for an interface energy band alignment. Benefiting from a raised hole mobility and a better charge mobility balance, the processing‐simple colloidal red QLEDs yielded the highest EQE of up to 17.4%. In particular, a very broad plateau of EQE values over 16.5% in the brightness of 400–10 000 cd m−2 is obtained. Moreover, the packaged QLEDs exhibit an excellent operation stability in ambient air. The T95 (time for the device brightness to decrease to 95% of its initial brightness) at an initial brightness of 1000 cd m−2 is 4160 h. The work highlights a promising ionic liquid strategy to guide the development of high‐performance and cost‐effective QLEDs. [ABSTRACT FROM AUTHOR]

Binders are required to dissipate huge mechanical stress and enhance the lithium‐ion diffusion kinetics of silicon anodes during cycling. Herein, a stress‐distribution binder with high ionic conductivity (GG‐g‐PAM) is constructed by grating polyacrylamide (PAM) onto ion‐conductive guar gum (GG) backbone. The mechanical stress distribution toward the grafted PAM chain enables the effective stress dissipation of the GG‐g‐PAM binder, and thus maintains a stable electrode‐electrolyte interface during cycling. The stress dissipation ability of the GG‐g‐PAM binder is confirmed by PeakForce atomic force microscopy experiments and finite element simulations. In addition, lithium complexation sites provided by oxygen heteroatoms in GG of the GG‐g‐PAM binder construct the Li‐ion pathways for facilitating Li ionic diffusion in the Si anodes. The good cyclabilities of Ah‐level pouch cells based on Si nanoparticle anodes strongly confirm GG‐g‐PAM as a desirable binder for practical Si anodes. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries (PIBs) are a favorable alternative to lithium‐ion batteries (LIBs) for the large‐scale electrochemical storage devices because of the high natural abundance of potassium resources. However, conventional PIB electrodes usually exhibit low actual capacities and poor cyclic stability due to the large radius of potassium ions (1.39 Å). In addition, the high reactivity of potassium metal raises serious safety concerns. These characteristics seriously inhibit the practical use of PIB electrodes. Here, zinc phosphide composites are rationally designed as PIB anodes for operation in a nonflammable triethyl phosphate (TEP) electrolyte to solve the above‐mentioned issues. The optimized zinc phosphide composite with 20 wt% zinc phosphate presents a high specific capacity (571.1 mA h g−1 at 0.1 A g−1) and excellent cycling performance (484.9 mA h g−1 with the capacity retention of 94.5% after 1000 cycles at 0.5 A g−1) in the KFSI‐TEP electrolyte. XPS depth profile analysis shows that the improved cycling stability of the composite is closely related to the reversible dynamic evolutions and conversions of the sulfur‐containing species in the solid electrolyte interphase (SEI) during the charge/discharge process. This dynamic reversible SEI concept may provide a new strategy for the design of superior electrodes for PIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrode materials for Supercapacitors were classified based on the dimensionality (0D, 1D, 2D and 3D). • The existing electrode materials were systematically classified based on chemical composition. • Innovative synthetic strategies for the nanoarchitecture of electrode materials for Supercapacitors is provided. • Impact of nanoarchitectures on the electrochemical performance of supercapacitors were studied. Supercapacitors have garnered significant attention in recent years owing to their exceptional attributes, such as high power density, prolonged cycle stability, and the capacity to fulfil the gap between the traditional capacitor and lithium-ion battery. Nanostructures with different dimensions (zero-dimensional, 0D; one-dimensional, 1D; two-dimensional, 2D; and three-dimensional, 3D) were employed as electrodes. Such material's architecture at the nanoscale has resulted in outstanding electrochemical characteristics, contributing to the development of high-performance Supercapacitors. Recent advances in the design of nanostructured electrode materials for Supercapacitors were highlighted and new insight into the structure property relationship is provided in this authoritative review. Unique classification of electrode materials based on dimensionality, namely, 0D, 1D, 2D and 3D was provided with emphasis on performance, namely, specific capacitance, energy density, power density and cyclability. The impact of nanostructures on key Supercapacitor properties that include the specific capacitance, charge transfer kinetics, diffusion, rate capability, as well as cycle life were also highlighted. These insights serve as a guidance for the development of commercially viable Supercapacitors with applications in day to day life, for instance, in drones used in the war-zones. [ABSTRACT FROM AUTHOR]

The solubility feature of redox electrolyte is a key factor to influence the performance of salt removal in redox flow electrode capacitive deionization. Herein, a novel redox flow desalination using ionic liquid (IL) as the eco-friendly solvent is proposed, i.e., 1-ethyl-3-methylimidazolium acetate. The high salt removal rate of 4.82 μg·min−1·cm−2 was obtained at the current density of 11 mA·cm−2. The low energy consumption of 254.12 kJ·mol−1 was achievable in IL, compared with 466.3 kJ·mol−1 in aqueous solution and 317.86 kJ·mol−1 ethanol. In addition, a long-term test with 11 cycles was conducted, and the real seawater was desalinated to a freshwater standard in batch mode. This work is significant for development of low-energy consumption in redox flow desalination via the usage of novel ionic liquids as solvent. An ionic liquid redox flow desalination device is proposed with the excellent solubility of redox couples, low energy consumption, high removal rate, long-term stability, and environment friendliness. [Display omitted] • A novel redox desalination system using ionic liquid (IL) as the eco-friendly solvent is proposed. • The energy consumption in IL-based FCDI system is significantly reduced. • Ionic liquid showed environmental friendliness and excellent stability as FCDI solvent. • Seawater is desalinated to freshwater. [ABSTRACT FROM AUTHOR]

To improve hydrogen production (HP) performance of regular-porous structure (RPS), a columnar RPS with small specific surface area and high superficial area is developed. A numerical simulation model of regular-porous stainless steel structure (RPSSS) is established. Subsequently, heat transfer performance, pressure loss, temperature, methanol concentration, H 2 concentration distributions and HP performance of the columnar RPSSS with small specific surface area and high superficial area and the body-centered cubic RPSSS with high specific surface area and small superficial area are compared. Then, temperature, methanol concentration, H 2 concentration distributions and HP performance of axial and longitudinal size-enlarged columnar RPSSSs are studied. The results show that compared to the body-centered cubic RPSSS, the columnar RPSSS has higher methanol conversion, larger H 2 flow rate and higher CO selectivity. Especially in the condition of 300 °C wall temperature and 12 mL/h methanol-water mixture injection rate (MWMIR), the methanol conversion, H 2 flow rate and CO selectivity of the columnar RPSSS are increased by 12.3%, 9.24% and 30%, respectively, indicating that the superficial area of RPSSS is more important for its HP performance compared to its specific surface area. Compared to the longitudinal size-enlarged columnar RPSSS, the axial size-enlarged columnar RPSSS has higher methanol conversion, larger H 2 flow rate and higher CO selectivity. This research work provides a new method for the optimization of hydrogen production reaction support (HPRS). Hydrogen production numerical simulation model of columnar regular-porous stainless steel reaction support. [Display omitted] • A columnar regular-porous hydrogen production reaction support is proposed. • A numerical simulation model of regular-porous stainless steel structure is built. • Heat transfer ability and pressure loss of regular-porous structure are studied. • Temperature and reactant concentration of regular-porous structure are explored. • Hydrogen production performance of regular-porous structure is investigated. [ABSTRACT FROM AUTHOR]

Numerous efforts have been directed to fabricate the cost-effective structure for hydrogen evolution reaction (HER). However, it is still a challenging task for clean energy. Herein, mesoporous zinc sulfide nanoparticles with various contents of polyaniline have been synthesized using the solvothermal process. Morphological and structural analysis has been carried out in detail for HER activity in KOH electrolyte at pH 10.20 and 13.55. The hybrid of zinc sulfide and Polyaniline (ZnS-90 mg), exhibits a lower specific surface area of 5.54 m2 g-1 and a greater mesoporous size of 10.10 nm as compared to individual polyaniline nanofibers (75.13 m2 g-1 and 6.02 nm) and zinc sulfide nanoparticles (80.90 m2 g-1 and 6.81 nm) due to interface, which creates the unique characteristics as compared to PANI-Nbs and ZnS-NPs. Hybrid ZnS-90 mg, synergistically, exhibits the greater electrical conductivity of 17.90 × 10−4 Scm−1 and reveals the lower over potential of 168 mV with an onset potential of 41 mV at pH 13.55, and an over potential of 345 mV with an onset potential of 69 mV at pH 10.20 of 1 M KOH for HER activity at the state of art current density of 10 mAcm−2. Hybrid ZnS-90 mg also shows the smaller Tafel slope of 234 mVdec−1 with the greater turnover frequency of 5.22 ms-1 at pH 13.55, recommending the better HER activity. A symmetric system consisting of Hybrid ZnS-90 mg reveals the two reduction peaks, where the over potential has been measured as 524 mV at the current density of 2.76 mAcm−2 and 947 mV at the current density of 10 mAcm−2 at pH 13.55. The symmetric system exhibits a good Tafel slope of 26 mVdec−1 and suggests it is the suitable and cost-effective electrode structure for HER to produce clean hydrogen energy. • Hybrid ZnS and Polyaniline (90 mg), exhibits the lower specific surface area of 5.54 m2 g-1 due to interface. • Hybrid ZnS and Polyaniline (90 mg), synergistically, exhibits the greater electrical conductivity of 17.90 × 10−4 Scm−1. • Hybrid ZnS and Polyaniline (90 mg), reveals the over potential of 168 mV at pH 13.55 of 1 M KOH. • Symmetric system exhibits a good Tafel slope of 26 mVdec−1. [ABSTRACT FROM AUTHOR]

Abstract: Crystalline TiO2 thin films were synthesized on the Si and glass substrates by reactive sputtering in a HIPIMS+ coating system. The films with a bit oxygen deficiency were deposited on the Si and glass substrates at oxygen flux rate of 10sccm. The phase structure of the films changed with varying the parameters the MPP power pulse, the bias voltage, and working gas pressure. Anatase-dominant, anatase–rutile, and rutile films can be obtained by controlling the deposition parameters. The anatase-dominant and anatase–rutile TiO2 films possess good photoinduced hydrophilicity and photocatalytic properties. The rutile films exhibited high dielectric constant. The related mechanism and potential application was discussed. [Copyright &y& Elsevier]

As anodes for metal‐ion batteries, metal phosphides usually suffer from severe capacity degradation because of their huge volume expansion and unstable solid electrolyte interphase (SEI), especially for potassium‐ion batteries (PIBs). To address these issues, this study proposes amorphous phosphates acting as buffer materials. Ten types of metal phosphide composites embedded with in situ‐formed amorphous phosphates are prepared by one‐step ball milling using red phosphorus (RP) and the corresponding metal oxides (MOs) as starting materials. A zinc phosphide composite is selected for further study as a PIB anode. Benefitting from the effective suppression of volume variation, a KF‐rich SEI is formed on the electrode surface in the KFSI‐based electrolyte. The zinc phosphide composite exhibits a high reversible specific capacity and outstanding long‐term cycling stability (476 mAh g−1 over 350 cycles at 0.1 A g−1 after going through a rate capability test and 177 mAh g−1 after 6000 cycles at 1.0 A g−1) and thus achieves the best cycling performance among all reported metal phosphide‐based anodes for PIBs. This study highlights a low‐cost and effective strategy to guide the development of metal phosphides as high‐performance anodes for PIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Stable and recyclable catalysts are crucial to the peroxymonosulfate (PMS) based advanced oxidation process (AOPs) for wastewater treatment. Herein, nitrogen-rich carbon wrapped Fe 3 C (Fe 3 C@CN) on carbon felt (CF) substrate was synthesized by using Prussian blue (PB) loaded CF as the precursors. The obtained Fe 3 C@CN/CF catalyst was applied for degradation of bisphenol A (BPA) via the heterogeneous catalytic activation of PMS. Results showed that ~91.7%, 95.2%, 98.1% and 99.1% of BPA (20 mg/L) were eliminated in the Fe 3 C@CN/CF + PMS system within 4, 10, 20 and 30 min, respectively. The fast degradation kinetics is attributed to the production of abundant reactive species (OH, SO 4 − and 1O 2) in the Fe 3 C@CN/CF + PMS system, as demonstrated by the electron paramagnetic resonance spectroscopy and quench experiments. The Fe 3 C@CN/CF catalyst was stable and can be easily recycled by using an external magnet. The results indicated that the nanoconfined Fe 3 C endowed Fe 3 C@CN/CF with high stability and magnetic property and enabled the efficient electron transfer for PMS activation. This study provides a cost-effective approach for the fabrication of stable and recyclable Fe 3 C@CN/CF catalyst, and shed a new light on the rational design of multifunctional catalyst for advanced water remediation. [ABSTRACT FROM AUTHOR]

• We reported the challenges, outlooks and potential research directions for AIBs. • Challenges/outlooks involve anode design, electrolyte exploitation, cathode selection. • Research directions focus on sustainable, low-cost, and high-power density AIBs. • Acquisition of green and low-cost carbonaceous cathode materials is highlighted. Aluminum-ion batteries (AIBs) for electrochemical energy storage technologies are relatively new research hotspots because of their advantages, such as high theoretical specific capacity, lightweightness, zero pollution, safety, inexpensive and rich resource. Especially, AIBs possess the potential to achieve ultrafast charge and discharge speed because of three-electron redox reactions, becoming the most promising candidate for high power density rechargeable batteries. However, several serious drawbacks, such as passive film formation, anode corrosion, and cathode selection and preparation, hinder the large-scale application of these systems. Here, we introduce the principles of AIBs and review the challenges and outlooks of AIBs from various perspectives, including anode design and protection, electrolyte exploitation and battery design, and cathode selection and preparation. We comprehensively discuss the acquisition of green and low-cost carbonaceous cathode materials with high electrochemical performance. Furthermore, several perspectives on potential research directions for the development of high-power density AIBs are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyurethane/graphene composite (PU/G) is made by a simple solution blending process. • Dispersibility of graphene flakes loading content in PU matrix is optimized. • Impact strength of the PU/G coating is ∼ 50 % higher than that of PU coating. • Adhesive behavior (pull off value) of the PU/G coating is ∼ 50 % higher than that of PU coating. • PU/G coating perform much better long-term corrosion protection that of PU coating. Graphene-based polyurethane composites (PU/G) are prepared by a simple solution blending method to disperse defect-free graphene flakes (prepared via liquid phase exfoliation process) into the polyurethane matrix. The PU/G composite with 1 wt% of graphene flakes performs the significant improvement (∼50 %) of the impact strength (124 kg.cm) and adhesion behavior (∼2.3 MPa) with respect to that of pristine PU. The PU/G coating with 2 wt% of graphene achieves the highest long-term anti-corrosion performance after 150 immersed days in 3 wt% NaCl solution (with the stable impedance modulus of ∼2.7 × 1010 Ω.cm2) or after 2500 h of salt spray exposure in 5 wt% NaCl solution (no corrosive traces detected on aluminum substrate). [ABSTRACT FROM AUTHOR]

Highlights: The PEDOT:PSS flexible electrodes with a unique CF3SO3H treatment exhibited high electrical characteristics and stability. An energy level tuning effect was induced to create a suitable work function. Flexible organic solar cells yielded a record-high efficiency of 16.61%, a high flexibility, and a good thermal stability.Nonfullerene organic solar cells (OSCs) have achieved breakthrough with pushing the efficiency exceeding 17%. While this shed light on OSC commercialization, high-performance flexible OSCs should be pursued through solution manufacturing. Herein, we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid (CF3SO3H). Through a low-concentration and low-temperature CF3SO3H doping, the conducting polymer anodes exhibited a main sheet resistance of 35 Ω sq−1 (minimum value: 32 Ω sq−1), a raised work function (≈ 5.0 eV), a superior wettability, and a high electrical stability. The high work function minimized the energy level mismatch among the anodes, hole-transporting layers and electron-donors of the active layers, thereby leading to an enhanced carrier extraction. The solution-processed flexible OSCs yielded a record-high efficiency of 16.41% (maximum value: 16.61%). Besides, the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85 °C, demonstrating a high flexibility and a good thermal stability. [ABSTRACT FROM AUTHOR]

Flow-electrode capacitive deionization (FCDI) is a new sustainable desalination technology where continuous desalination can be achieved by the electrodialysis coupling method. However, its development is hindered owing to high energy consumption and low salt removal rate. Herein, by combining ferri-/ferrocyanide redox couple with flow activated carbon (AC)/carbon black (CB) slurry, continuous desalination process is achieved with a high salt removal rate of 1.31 μg cm−2 s−1 and low energy consumption of 102.68 kJ mol−1 at the current density 2.38 mA cm−2 (50 mA current for a 21 cm2 active area). The operating voltage plateau can be reduced to 0.69 V when 10 wt% AC/CB (mass ratio of 9:1) is mixed with 20 mM/20 mM ferri-/ferrocyanide as the flow electrodes, compared with more than 3 V for only carbon flow or redox medium alone. The influences of carbon content and current densities are further investigated to so that the performances can be controlled. This work enables the development of energy-saving desalination systems by coupling FCDI with redox desalination technique. Image 1 [ABSTRACT FROM AUTHOR]

Abstract Rational design of electrode structures has been recognized as an effective strategy to improve the electrochemical performance of electrode materials. Herein, we demonstrate an integrated electrode in which nickel hydroxide (Ni(OH) 2) nanosheets are deposited on both sides of chemical vapor deposition-grown graphene on Ni foam, which not only effectively optimizes electrical conductivity of Ni(OH) 2 , but also accommodates the structural deformation associated with the large volume change upon cycling. The synthesized Ni(OH) 2 /graphene/Ni(OH) 2 /Ni foam electrode exhibits a high specific capacity of 991 C g−1 at a current density of 1 A g−1, which is higher than the theoretical specific capacity of additive sum of Ni(OH) 2 and graphene, and retains 95.4% of the initial capacity after 5000 cycles. A hybrid supercapacitor is constructed by using Ni(OH) 2 /graphene/Ni(OH) 2 /Ni foam as the positive electrode and activated carbon on Ni foam as the negative electrode, which achieves a maximum energy density of 49.5 W h kg−1 at a power density of 750 W kg−1, and excellent cycling lifespans with 89.3% retention after 10000 cycles at 10 A g−1. [ABSTRACT FROM AUTHOR]

Abstract Rational electrode architectural design, favorable electrode composition, and versatile synthesis approach play a significant role in developing advanced electrodes for high-performance supercapacitor. In this work, we report a facile approach for fabricating 1D hierarchical CuO@Co x Ni 1−x (OH) 2 nanowire arrays grown on 3D highly conductive copper foam. The optimized CuO@Co 0.2 Ni 0.8 (OH) 2 electrode delivers an ultrahigh specific capacity of 374.7 mAh g−1 at 2 A g−1 with exceptional rate capability (301.7 mAh g−1 at 50 A g−1) and remarkable cycling stability (95.9% after 10 000 cycles at 50 A g−1). A flexible asymmetric solid-state supercapacitor (ASC) is fabricated using the optimized CuO@Co 0.2 Ni 0.8 (OH) 2 as the positive electrode, activated carbon-coated nickel foam as the negative electrode, and polyvinyl alcohol/KOH gel as electrolyte. The flexible ASC operating with a potential window of 0–1.6 V delivers an energy density of 46.5 Wh kg−1 with a power density of 526.9 W kg−1. The ASC also exhibits excellent cycling stability with a capacity retention of 84.3% after 10 000 cycles at a current density of 7 A g−1. Graphical abstract Image 1 Highlights • CuO@Co x Ni 1−x (OH) 2 nanowire arrays grown on 3D copper foam was fabricated. • The architecture delivered an ultrahigh specific capacity. • Flexible hybrid supercapacitor using CuO@Co 0.2 Ni 0.8 (OH) 2 was assembled. • The flexible devices displayed excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

As a promising candidate battery for large-scale energy storage, rechargeable aluminum-ion batteries (AIBs) are receiving considerable attention owing to high theoretical capacity and abundance of aluminum. Here, the authors report the electrospun NiS 2 –based cathode to stabilize anionic redox processes, exhibiting excellent Al storage performance. [Display omitted] • Preparation of unique NiS 2 nanomaterials with S-doped carbon coating structure. • Acquiring the mechanism of NiS 2 -based cathode material through detailed characterization. • The NiS 2 /SC@SCNF cathode alleviates polysulfide dissolution for durable Al storage. • Superior cycling stability of NiS 2 /SC@SCNF (76 mAh/g after 500 cycles, 97% C eff). Rechargeable aluminum-ion batteries (AIBs) are receiving considerable attention as a desirable device for large-scale energy storage owing to high theoretical capacity and abundance of aluminum. However, due to strong charge of Al3+, the state-of-the-art AIBs often show sluggish electrode reaction kinetics and rapid capacity fading and the available cathode materials always demonstrate poor structural stability, thereby greatly hindering their practical use. NiS 2 with anion redox species (S 2 2– dimers) and favorable electronic conductivity is a promising cathode to boost the performance of AIBs in terms of reversible capacity, rate capability and cycling stability. Here, we report a systematic investigation of the Al storage behavior and mechanism of NiS 2 /S-doped carbon (NiS 2 /SC) cathode based on a series of electrochemical tests and ex situ measurements. We further develop electrospun NiS 2 /S-doped carbon@S-doped carbon nanofiber (NiS 2 /SC@SCNF) structure as the cathode of AIBs. The as-fabricated AIB delivers an unprecedented Al3+ storage performance with a stable capacity of 76 mAh/g at 0.5 A/g CV 500 cycles and a superior cycling Coulombic efficiency of 97 %. This study reveals that NiS 2 /SC@SCNF undergoes a reversible evolution of initial Al3+ insertion followed by anionic redox between S 2 2– and S2–, paving the road for the futher development of NiS 2 –based cathodes for AIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The redox flow desalination is driven by the thermoelectric power instead of off-the-shelf electricity. • The diluted water of 344.3 ppm can be obtained from initial 5000 ppm at 65 K temperature difference. • The salt removal efficiency is up to 93.1%. • The desalination performance can be controllable by adjusting the temperature differences. • Simple to assemble and operate the system in places with the temperature differences. How to effectively reduce the consumption of electrical energy is a key topic in many studies of electrochemical desalination. In this work, we use the temperature difference to drive a continuous process of dialysis desalination. The system consists of a thermoelectric unit and a desalination unit connected in series. The thermoelectric unit includes a thermoelectric generator (TEG), a heater as heat source and an air-cooled heat sink to generate electricity and for the desalination unit. The desalination unit contains two platinum-coated hydrophobic carbon cloths as current collectors, a mixture of [Fe(CN) 6 3-/4- as anolyte and catholyte, concentrated and diluted salt streams with two cationic and one anionic exchange membranes separated configuration (CEM|AEM|CEM). During the charging process driven by temperature difference, chloride and sodium ions in the diluted salt stream move to the concentrated salt stream and cathodic reservoir, respectively. The results show that the concentration of brine drops significantly from 5,000 ppm to 344.3 ppm as the current decreases to 0.06 mA from the initial 1.30 mA when the temperature difference is maintained at 65 K. Concurrently, the average salt removal rate is up to 8.8 μg cm−2 min−1 and average heat consumption is 284.3 MJ mole-1. Moreover, the influences from the temperature difference, salt feeds content and electrolyte concentration are also investigated in detail. This research has the potential application for the freshwater obtainment via the utilization of waste heat, and will be significant in places with the shortage of the electrical energy such as ships, islands and oceans with the temperature differences. [ABSTRACT FROM AUTHOR]

• 3D microflowers Fe–NiCoP@C on the nickel foam is synthesized. • Fe dopant modulates the electron conductivity and catalytic properties of Fe-NiCoP. • The carbon layer improves the electron conductivity and stabilizes the electrolyte at the interface. • The HSAB displays a discharge voltage of 2.74 V at 0.01 mA cm−2 and the state-of-the-art power density of 621 mW g−1. Nickel cobalt phosphide (NiCoP) is emerging as a potential electrocatalyst towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, its ORR/OER activities are sluggish. Here, we investigated the roles of iron dopants in the Fe-doped NiCoP (Fe–NiCoP) in order to boost its ORR/OER kinetics. The density functional theory (DFT) calculations reveal that the Fe dopant effectively modulates the electron conductivity of NiCoP and reduces binding energies of the reaction intermediates towards rate-determining steps of ORR and OER. A binder-free 3D microflowers morphology of the Fe–NiCoP embedded in the amorphous carbon layer (Fe–NiCoP@C) catalyst on the nickel foam was prepared as the air cathode for the hybrid sodium-air battery (HSAB). The HSAB displays a discharge voltage of 2.74 V at 0.01 mA cm−2 with excellent round trip efficiency of 93.26 % at the 500th cycle and state-of-the-art power density of 621 mW g−1. [ABSTRACT FROM AUTHOR]

This work presents a systematical experimental and density functional theory (DFT) studies to reveal the mechanism of NO reduction by H 2 reaction over platinum nanoparticles (NPs) deposited on boron-doped graphene (denoted as Pt/BG) catalyst. Both characterizations and DFT calculations identified boron (in Pt/BG) as an additional NO adsorption site other than the widely recognized Pt NPs. Moreover, BG led to a decrease of Pt NPs size in Pt/BG, which facilitated hydrogen spillover. The mathematical and physical criteria of the Langmuir-Hinshelwood dual-site kinetic model over the Pt/BG were satisfied, indicating that adsorbed NO on boron (in Pt/BG) was further activated by H-spillover. On the other hand, Pt/graphene (Pt/Gr) demonstrated a typical Langmuir-Hinshelwood single-site mechanism where Pt NPs solely served as active sites for NO adsorption. This work helps understand NO-H 2 reaction over Pt/BG and Pt/Gr catalysts in a closely mechanistic view and provides new insights into roles of active sites for improving the design of catalysts for NO abatement. ga1 • Systematic experimental and DFT study was conducted for NO‒H 2 reaction. • Doped-boron of Pt/BG was identified as an additional adsorption site for NO. • Dual-site kinetic model was successfully developed for Pt/BG case. • Single-site kinetic model was adopted for Pt/Gr case. • H-assisted N‒O cleavage was identified as the activation step. [ABSTRACT FROM AUTHOR]

• Carbon composited with pseudocapacitive material emerged with great interest. • The electrochemical performance of hybrid composites is discussed systematically. • This review provides a comprehensive study. • Future perspectives and challenges in practical application also discussed. Supercapacitors are considered reliable devices for energy storage. However, supercapacitor has some limitations, such as relatively low capacitance and low energy density, which affect it as a promising energy storage device. In this context, carbon based nanocomposites have been widely studied in the past few years due to their excellent physical, mechanical and electrical properties. A lot of studies have been reported on carbon based materials with different 0D, 1D, 2D and 3D carbon nanostructures. The unique combination of pseudo-material with carbon material greatly improves the electrochemical performance of the composite as compared to individual candidate. However, developing high energy density supercapacitor devices with high cycling stability in a simple and cost effective way is still a challenge. This review provides the current progress on the carbon based pseudo-material composites for supercapacitor application in a well-systematic and easy manner which can guide the early researchers and emerging scientists dealing with or interested in supercapacitor. [ABSTRACT FROM AUTHOR]

A low water-solubility but hydrophilic coating of CaF 2 is demonstrated to be effective in mitigating the susceptibility of nickel-rich cathodes to moisture and even water. The ability of the cathode to resist water erosion is not inherently linked to either hydrophobicity or hydrophilicity, but lies in robust chemical bonding within the protective layer exhibiting low water solubility.

Semitransparent perovskite solar cells (ST-PSCs) have great potential in building integrated photovoltaics. However, semitransparent devices suffer from a low electron mobility and an imbalanced charge-carrier transport, leading to an unsatisfactory power conversion efficiency (PCE) and limited stability. Herein, we report a high-performance ST-PSC via the incorporation of a special Lewis base. A better perovskite with an improved crystallinity and less defects was achieved, and a matched energy level alignment between the perovskite and [6,6]-phenyl-C 61 -butyric acid methyl ester was also induced, thereby leading to a high electron mobility and an exceptional balance of hole and electron mobility approaching 1 : 1. The prepared ST-PSC exhibited a PCE of 20.22% at average visible transmittance (AVT) of 4.93%, 18.32% at AVT of 14.38%, and 15.00% at AVT of 25.65%. These PCEs are the highest values among those ST-PSCs based on top metallic electrodes at a close AVT. The ST-PSCs maintained 92% of the initial PCE in storage for 1000 h, and they held 84% of the initial PCE under the continuous maximum power point tracking measurement for 530 hours. The work paves the way to realize ST-PSCs with a high PCE, high light utilization efficiency and substantially enhanced stability.

Transition metal oxides (TMOs) are recognized as high-efficiency electrocatalyst systems for restraining the shuttle effect in lithium-sulfur (Li-S) batteries, owing to their robust adsorption capabilities for polysulfides. However, the sluggish catalytic conversion of Li2S redox and severe passivation effect of TMOs exacerbate polysulfide shuttling and reduce the cyclability of Li-S batteries, which significantly hinders the development of TMOs electrocatalysts. Here, through the anion-cation doping approach, dual incorporation of phosphorus and molybdenum into MnO2 (P,Mo-MnO2) was engineered, demonstrating effective mitigation of the passivation effect and allowing for the simultaneous immobilization of polysulfides and rapid redox kinetics of Li2S. Both experimental and theoretical investigations reveal the pivotal role of dopants in fine-tuning the d-band center and optimizing the electronic structure of MnO2. Furthermore, this well-designed configuration processes catalytic selectivity. Specifically, P-doping expedites rapid Li2S nucleation kinetics by minimizing reaction-free energy, while Mo-doping facilitates robust Li2S dissolution kinetics by mitigating decomposition barriers. This dual-doping approach equips P,Mo-MnO2 with robust bi-directional catalytic activity, effectively overcoming passivation effect and suppressing the notorious shuttle effect. Consequently, Li-S batteries incorporating P,Mo-MnO2-based separators demonstrate favorable performance than pristine TMOs. This design offers rational viewpoint for the development of catalytic materials with superior bi-directional sulfur electrocatalytic in Li-S batteries., (© 2024 Wiley‐VCH GmbH.)

Aqueous zinc-iodine batteries are promising candidates for large-scale energy storage due to their high energy density and low cost. However, their development is hindered by several drawbacks, including zinc dendrites, anode corrosion, and the shuttle of polyiodides. Here, the design of 2D-shaped tungsten boride nanosheets with abundant borophene subunits-based active sites is reported to guide the (002) plane-dominated deposition of zinc while suppressing side reactions, which facilitates interfacial nucleation and uniform growth of zinc. Meanwhile, the interfacial d-band orbits of tungsten sites can further enhance the anchoring of polyiodides on the surface, to promote the electrocatalytic redox conversion of iodine. The resulting tungsten boride-based I 2 cathodes in zinc-iodine cells exhibit impressive cyclic stability after 5000 cycles at 50 C, which accelerates the practical applications of zinc-iodine batteries., (© 2024 Wiley‐VCH GmbH.)

Heterogeneous structures and doping strategies have been intensively used to manipulate the catalytic conversion of polysulfides to enhance reaction kinetics and suppress the shuttle effect in lithium-sulfur (Li-S) batteries. However, understanding how to select suitable strategies for engineering the electronic structure of polar catalysts is lacking. Here, a comparative investigation between heterogeneous structures and doping strategies is conducted to assess their impact on the modulation of the electronic structures and their effectiveness in catalyzing the conversion of polysulfides. These findings reveal that Co 0.125 Zn 0.875 Se, with metal-cation dopants, exhibits superior performance compared to CoSe 2 /ZnSe heterogeneous structures. The incorporation of low Co 2+ dopants induces the subtle lattice strain in Co 0.125 Zn 0.875 Se, resulting in the increased exposure of active sites. As a result, Co 0.125 Zn 0.875 Se demonstrates enhanced electron accumulation on surface Se sites, improved charge carrier mobility, and optimized both p-band and d-band centers. The Li-S cells employing Co 0.125 Zn 0.875 Se catalyst demonstrate significantly improved capacity (1261.3 mAh g -1 at 0.5 C) and cycle stability (0.048% capacity delay rate within 1000 cycles at 2 C). This study provides valuable guidance for the modulation of the electronic structure of typical polar catalysts, serving as a design directive to tailor the catalytic activity of advanced Li-S catalysts., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

Catalytic conversion of polysulfides emerges as a promising approach to improve the kinetics and mitigate polysulfide shuttling in lithium-sulfur (Li-S) batteries, especially under conditions of high sulfur loading and lean electrolyte. Herein, we present a separator architecture that incorporates double-terminal binding (DTB) sites within a nitrogen-doped carbon framework, consisting of polar Co 0.85 Se and Co clusters (Co/Co 0.85 Se@NC), to enhance the durability of Li-S batteries. The uniformly dispersed clusters of polar Co 0.85 Se and Co offer abundant active sites for lithium polysulfides (LiPSs), enabling efficient LiPS conversion while also serving as anchors through a combination of chemical interactions. Density functional theory calculations, along with in situ Raman and X-ray diffraction characterizations, reveal that the DTB effect strengthens the binding energy to polysulfides and lowers the energy barriers of polysulfide redox reactions. Li-S batteries utilizing the Co/Co 0.85 Se@NC-modified separator demonstrate exceptional cycling stability (0.042% per cycle over 1000 cycles at 2 C) and rate capability (849 mAh g -1 at 3 C), as well as deliver an impressive areal capacity of 10.0 mAh cm -2 even in challenging conditions with a high sulfur loading (10.7 mg cm -2 ) and lean electrolyte environments (5.8 μL mg -1 ). The DTB site strategy offers valuable insights into the development of high-performance Li-S batteries.

Noble metals (Pt) and metal oxides (IrC and RuO 2 ) are heavily utilized as benchmark electrocatalysts for alkaline water splitting; however, these materials possess several drawbacks including high cost, poor selectivity and stability, and high environmental impact. To address these issues, we synthesized a novel metal-free conducting polypyrrole-polythiophene (Ppy-Ptp) copolymer and a separate Ppy electrode material for water-splitting applications. The Ppy-Ptp and Ppy electrocatalysts exhibited remarkable activity in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The optimal Ppy-Ptp (1:3) formulation, when deposited on a conductive nickel foam (NF) substrate, exhibited an exceptional OER performance with a low overpotential of approximately 250 mV at 20 mAcm -2 , thereby outperforming the benchmark IrC/NF electrocatalyst (290 mV, 20 mAcm -2 ). Additionally, a similarly prepared Ppy/NF electrocatalyst exhibited an extraordinary HER performance with an overpotential of approximately 72 mV at 10 mA cm -2 . Furthermore, an alkaline anion-exchange membrane (AEM) electrolyzer incorporating Ppy-Ptp (1:3) and Ppy as the anode and cathode materials, respectively, displayed operating potentials of 1.55, 1.70, and 1.78 V at 10, 50, and 100 mA cm -2 , which are lower than those observed in previously reported electrolyzers. This electrolyzer also exhibited considerable operational endurance over 50 h at 50 mA cm -2 , over which a negligible decay of 0.02 V was observed. The novel polymer-based metal-free catalysts presented herein therefore exhibit considerable potential as alternative electrocatalytic materials for sustainable industrial-scale H 2 synthesis.

Polymer-based solid-state batteries (SSBs) have received increasing attentions due to the absence of interfacial problems in sulfide/oxide-type SSBs, but the lower oxidation potential of polymer-based electrolytes greatly limits the application of conventional high-voltage cathode such as LiNi x Co y Mn z O 2 (NCM) and lithium-rich NCM. Herein, this study reports on a lithium-free V 2 O 5 cathode that enables the applications of polymer-based solid-state electrolyte (SSE) with high energy density due to the microstructured transport channels and suitable operational voltage. Using a synergistic combination of structural inspection and non-destructive X-ray computed tomography (X-CT), it interprets the chemo-mechanical behavior that determines the electrochemical performance of the V 2 O 5 cathode. Through detailed kinetic analyses such as differential capacity and galvanostatic intermittent titration technique (GITT), it is elucidated that the hierarchical V 2 O 5 constructed through microstructural engineering exhibits smaller electrochemical polarization and faster Li-ion diffusion rates in polymer-based SSBs than those in the liquid lithium batteries (LLBs). By the hierarchical ion transport channels created by the nanoparticles against each other, superior cycling stability (≈91.7% capacity retention after 100 cycles at 1 C) is achieved at 60 °C in polyoxyethylene (PEO)-based SSBs. The results highlight the crucial role of microstructure engineering in designing Li-free cathodes for polymer-based SSBs., (© 2023 Wiley-VCH GmbH.)

Mn-based layered oxide is extensively investigated as a promising cathode material for potassium-ion batteries due to its high theoretical capacity and natural abundance of manganese. However, the Jahn-Teller distortion caused by high-spin Mn 3+ (t 2g 3 e g 1 ) destabilizes the host structure and reduces the cycling stability. Here, K 0.02 Na 0.55 Mn 0.70 Ni 0.25 Zn 0.05 O 2 (denoted as KNMNO-Z) is reported to inhibit the Jahn-Teller effect and reduce the irreversible phase transition. Through the implementation of a Zn-doping strategy, higher Mn valence is achieved in the KNMNO-Z electrode, resulting in a reduction of Mn 3+ amount and subsequently leading to an improvement in cyclic stability. Specifically, after 1000 cycles, a high retention rate of 97% is observed. Density functional theory calculations reveals that low-valence Zn 2+ ions substituting the transition metal position of Mn regulated the electronic structure around the MnO bonding, thereby alleviating the anisotropic coupling between oxidized O 2- and Mn 4+ and improving the structural stability. K 0.02 Na 0.55 Mn 0.70 Ni 0.25 Zn 0.05 O 2 provided an initial discharge capacity of 57 mAh g -1 at 100 mA g -1 and a decay rate of only 0.003% per cycle, indicating that the Zn-doped strategy is effective for developing high-performance Mn-based layered oxide cathode materials in PIBs., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)

In this work, a solar-driven redox flow desalination system is reported, which combines a solar cell based on a Bi 2 O 3 photoanode and a redox flow desalination cell through an integrated electrode. The Bi 2 O 3 film was prepared through a simple one-step water bath deposition method and served as a photoanode after the coating of the N719 dye. The activated carbon (AC)-coated graphite paper served as both the integrated electrode and counter electrode. The I 3 - /I - redox electrolyte circulates in the solar cell channel between the photoanode and intergrated electrode, while the [Fe(CN) 6 ] 4- /[Fe(CN) 6 ] 3 - electrolyte circulates in the redox flow desalination part between the integrated electrode and counter electrode. This dye-sensitized solar-driven desalination cell is capable of achieving a maximum salt removal rate of 62.89 μg/(cm 2 ·min) without consuming any electrical power. The combination of the solar cell and redox flow desalination is highly efficient with double functions of desalination and energy release using light as a driving force. This current research work is significant for the development of efficient and stable photoanode materials in photoelectrochemical desalination.

Silicon oxide (SiO x ) has outstanding capacity and stable lithium-ion uptake/removal electrochemistry as a lithium-ion anode material; however, its practical massive commercialization is encumbered by unavoidable challenges, such as dynamic volume changes during cycling and inherently inferior ionic conductivities. Recent literature has offered a consensus that binders play a critical role in affecting the electrochemical performance of Si-based electrodes. Herein, we report an aqueous binder, γ-polyglutamic acid cross-linked by epichlorohydrin (PGA-ECH), that guarantees enhanced properties for SiO x anodes to implement long-term cycling stability. The abundant amide, carboxyl, and hydroxyl groups in the binder structure form strong interactions with the SiO x surface, which contribute strong interfacial adhesion. The robust covalent interactions and strong supramolecular interactions in the binder ensure mechanical strength and elasticity. Additionally, the interactions between lithium ions and oxygen (nitrogen) atoms of carboxylate (peptide) bonds, which serve as a Lewis base, facilitate the diffusion of lithium ions. A SiO x anode using this PGA-ECH binder exhibits an impressive initial discharge capacity of 1962 mA h g -1 and maintains a high capacity of 900 mA h g -1 after 500 cycles at 500 mA g -1 . Meanwhile, the assembled SiO x ||LiNi 0.6 Co 0.2 MnO 0.2 full cell shows a reversible capacity of 155 mA g -1 and displays 73% capacity retention after 100 cycles.

Conducting polymers have received tremendous attentions owing to their great potentials to harvest both luminous and thermal energies. Here, we reported a flexible transparent electrode of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with highly electrical conductivity and raised Seebeck coefficient via thionyl chloride treatments. The comprehensive studies of optical, electrical, morphological, structural, and thermoelectrical properties, work function, and stability of the PEDOT:PSS transparent electrodes were systematically evaluated and described. On the basis of the PEDOT:PSS transparent electrodes, the resultant flexible organic solar cells yielded a high power conversion efficiency of 15.12%; meanwhile, the flexible thermoelectricities exhibited the raised power factor of 115.9 μW m -1  K -2 , which outperformed the four kinds of rigid thermoelectricities with conventional acid and base treatments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wan, Fan, Li, Li, Zhang, Hui, Huang, Kang and Qian.)

A lithium-sulfur (Li-S) battery based on multielectron chemical reactions is considered as a next-generation energy-storage device because of its ultrahigh energy density. However, practical application of a Li-S battery is limited by the large volume changes, insufficient ion conductivity, and undesired shuttle effect of its sulfur cathode. To address these issues, an aqueous supramolecular binder with multifunctions is developed by cross-linking sericin protein (SP) and phytic acid (PA). The combination of SP and PA allows one to control the volume change of the sulfur cathode, benefit soluble polysulfides absorbing, and facilitate transportation of Li + . Attributed to the above merits, a Li-S battery with the SP-PA binder exhibits a remarkable cycle performance improvement of 200% and 120% after 100 cycles at 0.2 C compared with Li-S batteries with PVDF and SP binders. In particular, the SP-PA binder in the electrode displays admirable flame-retardant performance due to formation of an isolating layer and the release of radicals.

Multifunctional electrocatalytic desalination is a promising method to increase the production of additional valuable chemicals during the desalination process. In this work, a multifunctional desalination device was demonstrated to effectively desalinate brackish water (15 000 ppm) to 9 ppm while generating formate from captured CO 2 at the Bi nanoparticle cathode and releasing oxygen at the Ir/C anode. The salt feed channel is sandwiched between two electrode chambers and separated by ion-exchange membranes. The electrocatalytic process accelerates the transportation of sodium ions and chloride ions in the brine to the cathode and anode chamber, respectively. The fastest salt removal rate to date was obtained, reaching up to 228.41 μg cm -2 min -1 with a removal efficiency of 99.94%. The influences of applied potential and the concentrations of salt feed and electrolyte were investigated in detail. The current research provides a new route towards an electrochemical desalination system.

Conventional polymer binder in a lithium-sulfur (Li-S) battery, poly(vinylidene fluoride) (PVDF), suffers from insufficient ion conductivity, poor polysulfide-trapping ability, weak mechanical property, and requirement of organic solvents, which significantly encumber the industrial application of Li-S battery. Herein, a water-soluble binder with trifunctions, covalently cross-linked quaternary ammonium cationic starch (c-QACS), is developed to confront these issues. Similar to the poly(ethylene oxide) solid electrolytes, the c-QACS binder remarkably improves Li + ion transfer capacity. The abundant O actives endow the c-QACS binder with admirable lithium polysulfide-trapping capability to retard the shuttle effect. In addition, the formed 3D network effectively maintains the electrode integrity during cycling. Benefiting from the above merits, the sulfur cathode with the c-QACS binder demonstrates a performance improvement of 300 and 150% compared with sulfur cathode with PVDF and bulk QACS binder after 100 cycles at 0.2C.

It is challenging to develop highly efficient and stable multifunctional electrocatalysts for improving the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the oxygen reduction reaction (ORR) for sustainable energy conversion and storage systems such as water-alkali electrolyzers (WAEs) and hybrid sodium-air batteries (HSABs). In this work, sub-nm Pt nanoclusters (NCs) on defective NiFe layered double hydroxide nanosheets (Ni x Fe LDHs) are synthesized by a facile electrodeposition method. Due to the synergistic effect between Pt NCs and abundant atomic M (II) defects, along with hierarchical porous nanostructures, the Pt/Ni x Fe LDHs catalysts exhibit superior trifunctional electrocatalytic activity and durability toward the HER/OER/ORR. A WAE fabricated with Pt/Ni x Fe LDHs electrodes needs 1.47 V to reach a current density of 10 mA cm -2 , much lower than that of the mixed 20% Pt/C and 20% Ir/C catalysts. An HSAB assembled by Pt/Ni x Fe LDHs as a binder-free air cathode displays a high open-circuit voltage, a narrow overpotential gap, and remarkable rechargeability. This work provides a feasible strategy for constructing freestanding efficient trifunctional electrocatalysts for sustainable energy conversion and storage systems.

In the search for well-defined phosphor materials for white NUV-LEDs, the highly enhanced luminous efficacy by N(3-) doping as well as color tunability via Ca substitution has been successfully obtained in Ba2-xCaxSiO4-δN2/3δ:Eu(2+) (x = 0.0, 0.5, 0.8, 1.0) phosphors. With increasing Ca-substitution rate, the crystal structures of the phosphor materials are changed from the primitive orthorhombic structure to the hexagonal one, so that the CIE coordinates move from bluish-green (at Ca = 0.0), to blue (at Ca = 0.5), and finally to near white region (at Ca = 0.8 and 1.0) in these materials. In combination with the results from X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy, the elemental distribution of the phosphor materials found from secondary-ion mass spectrometry (SIMS) directly indicates that the N(3-) ions are partially substituted for O(2-) ions into the crystal lattice of alkaline-earth orthosilicates and thus critically improves the color-tunable photoluminescence (PL) and electroluminescence (EL) efficiency of the phosphor materials for white NUV-LEDs. The newly found "the N(3-) doping and color-tunable effect" on large PL and EL enhancement may provide a platform in the discovery of new efficient phosphors for solid state lighting.

Water is detrimental to the performance of organic light-emitting devices and organic solar cells. A novel weight gain test (WGT) was introduced and demonstrated to measure the low permeation of water vapor through a metallic barrier coating on a polymer substrate. By using the WGT, the values of solubility, diffusivity and permeability for a sample are obtained with a simple experimental setup and diffusion equation. The WGT method has potential for the measurement of water-vapor permeation properties for samples with good barrier properties and irregular shape.

Zinc sulfide [ZnS] thin films were deposited on glass substrates using radio frequency magnetron sputtering. The substrate temperature was varied in the range of 100°C to 400°C. The structural and optical properties of ZnS thin films were characterized with X-ray diffraction [XRD], field emission scanning electron microscopy [FESEM], energy dispersive analysis of X-rays and UV-visible transmission spectra. The XRD analyses indicate that ZnS films have zinc blende structures with (111) preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM data also reveal that the films have nano-size grains with a grain size of approximately 69 nm. The films grown at 350°C exhibit a relatively high transmittance of 80% in the visible region, with an energy band gap of 3.79 eV. These results show that ZnS films are suitable for use as the buffer layer of the Cu(In, Ga)Se2 solar cells.