Search

For Li‐ion and Na‐ion batteries, the intercalation behavior of graphite anodes is quite different. While Li‐ions intercalate, Na‐ions only co‐intercalate with solvent molecules from the electrolyte solution leading to ternary graphite intercalation compound (t‐GIC) formation along with an expansion of the graphite interlayer spacing to 1.2 nm. This large interlayer spacing represents a micropore with parallel slit geometry. Little is known about t‐GIC formation, but it is commonly believed that throughout the reaction the ion is accompanied by either a full or partial solvation shell. Here, it is elucidated for the first time, using two independent methods – mass measurements and electrochemical impedance spectroscopy – supplemented by operando microscopy, entropymetry and simulations, that the storage mechanism is far more complex. A new model for the electrochemical solvent co‐intercalation process is proposed: As soon as solvated ions enter, the graphite structure is flooded with free solvents, which are subsequently replaced by solvated ions. Close to full sodiation, few free solvents remain and structural rearrangement take place to reach the full storage capacity. Thus, t‐GICs represent a unique case of switchable microporous systems and hence appear as a bridge between ion storage in the bulk phase and in micropores, i.e., between batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

Pursuing carbon neutrality has invigorated extensive investigations into sustainable and cost‐effective power sources. Iron‐air batteries (IAB) have emerged as a promising option due to their high energy density, low cost, and environmental friendliness. However, conventional IABs grapple with issues such as electrode passivation, low round‐trip energy efficiency, and parasitic hydrogen evolution. This study introduces a redox‐mediated iron‐air fuel cell (RM‐IAFC) to surmount these limitations. The RM‐IAFC employs a pair of redox mediators, respectively, in anolyte and catholyte tanks, enabling the iron oxidation and oxygen reduction reaction processes to be liberated from the electrodes. This configuration decouples energy storage and power generation, allowing fast refueling and offering operation flexibility and scalability while eliminating the need for expensive catalysts. With these salient features, the RM‐IAFC paves the way for sustainable and scalable power generation, particularly for stationary applications. [ABSTRACT FROM AUTHOR]

Zn powder is considered as a potential Zn metal anode for aqueous Zn‐ion batteries. However, restricted ion/electron transfer and volume effect‐caused electrical contact failure in conventional polymer binder composited Zn powder anodes deteriorate their electrochemical performance. Here, a high‐performance soft solid‐like viscoelastic Zn powder composite anode is proposed based on an oligomer gluing strategy. Benefiting from the viscoelastic properties, the soft‐solid Zn powder composite (ss‐ZnP) anode has significantly enhanced charge transfer, alleviated volume effect, and homogenized interfacial electric field, leading to fast plating/stripping kinetics and dendrite‐free deposition morphology. Furthermore, the assembled NH4V4O10‖ss‐ZnP full cell delivers higher capacity (510 mAh g−1 at 0.1A g−1, 300 mAh g−1 at 1A g−1) and longer lifespan up to 500 cycles at 1 A g−1, superior to conventional polymer binder composited Zn powder anode and other reported rheological Zn powder‐based anodes. Apart from the electrochemical merits, this soft matter‐based design also endows the ss‐ZnP electrode with free‐standing and malleable properties which greatly expand its practical application. [ABSTRACT FROM AUTHOR]

Cd alloying has been theoretically proved to be an effective strategy to suppress Cu‐Zn antisite defects and related defect cluster for improving device performance of pure sulfide kesterite Cu2ZnSnS4 (CZTS) thin film solar cells. However, the potential of Cd alloying has not been fully realized by solely doping without further post heat‐treatment. Here, Cd alloying CZTS (Cu2(Zn,Cd)SnS4, CZCTS) is reported through dimethyl sulfoxide (DMSO) solution and how alloying concentration affects reaction path, grain growth, and electronic properties of the CZCTS absorbers is investigated. This study found that Cd can be incorporated into CZTS through direct phase transformation grain growth, which sufficiently suppresses band tailing. High quality CZCTS absorber films and efficient solar cells are fabricated within a wide range of alloy concentration. A champion CZCTS device with a power conversion efficiency of 12.3% is achieved at 35% Cd concentration without any post heat treatment, improved by over 70% compared to 7.0% of CZTS. This device exhibits a high VOC gain to the Shockley–Queisser (Voc/VocSQ = 59.7%), the lowest VOC deficit achieved in pure sulfide kesterite solar cells. The results demonstrate the importance of the Cd alloying strategy for mitigating band tailing and achieving high efficiency pure sulfide kesterite solar cells. [ABSTRACT FROM AUTHOR]

Due to their environmental friendliness, low cost, and versatility in applications, flexible Cu2ZnSn(S, Se)4 (CZTSSe) solar cells have garnered significant attention in recent years. However, the lack of alkali metal elements in the flexible substrate has posed a challenge to the advancement of flexible CZTSSe solar cells. In this study, a post‐treatment strategy is proposed involving Rb ions to simultaneously regulate the surface properties of the CZTSSe film and the reactions during the CdS chemical bath deposition (CBD) process. Material and chemical characterization results confirm that Rb ions effectively passivate the detrimental Se0 defect, leading to a more active surface for the CdS epitaxial growth. Additionally, the coordination between Rb ions and thiourea in the CBD solution improves the ion‐by‐ion deposition of the CdS layer. These beneficial effects significantly improve the heterojunction interface and consequently enable the flexible CZTSSe solar cell to achieve a record total‐area efficiency of 12.84% and excellent bending performance. Overall, the heterojunction interface regulation strategy employed in this work, along with the obtained remarkable results, offer promising prospects for the development of flexible CZTSSe solar cells. [ABSTRACT FROM AUTHOR]

Bipolar membranes in forward bias have the potential to address several challenges of alkaline zero‐gap CO2 electrolyzers. However, the inevitable gas evolution of CO2 at the membrane junction typically leads to delamination and failure of the membrane after a few hours, limiting its applicability in electrolyzers so far. In this work, a bipolar membrane with a perforated anion exchange layer is presented that allows the CO2 gas to flow back to the cathode and thus preventing accumulation of gas at the junction. This configuration for the first time enables stable operation of a forward bias bipolar membrane showing a degradation rate of 0.5 mV h−1 in a 200 h constant current hold at 100 mA cm−2 and 3.1 V. Highest reported energy efficiency of EECO = 39% and Faradaic efficiency of FECO = 96% at 200 mA cm−2 among forward bipolar membranes prove that the perforated membrane does not compromise efficiency. A maximum CO2 single‐pass conversion of 52% at 0.75 mLCO2 min−1 cm−2 and a low specific energy consumption of 665 kJ mol−1 CO2 shows that this concept is superior not only to other bipolar membranes in the literature, but potentially also to conventional anion exchange membrane‐based electrolyzers. [ABSTRACT FROM AUTHOR]

Polyaniline is the most famous conducting polymer and also a promising organic cathode material for rechargeable batteries, however, it has demonstrated poor utilization of its theoretical capacity (294 mAh g−1) and inferior cycling stability in previous studies. Herein, for the first time, its fully reduced form, i.e., leucoemeraldine base (LB), is studied as an alternative to the commonly used emeraldine salt and base (ES and EB). For the three different forms, the precise structures are carefully determined, and the electrochemical performance are systematically investigated. Within 2.0−4.3 V, LB realizes almost full capacity utilization (92%) that is much superior to those of ES and EB. Within 2.0−4.2 V, it shows both high reversible capacity (277 mAh g−1) and cycling stability (84% capacity retention after 1000 cycles). The combination of electrochemical analysis, density functional theory calculation, and ex situ characterization reveals that the capacity utilization is positively associated with the pristine proportion of ─NH─ groups, and the capacity fading is caused by the irreversible electrochemical deprotonation at high charge potential. This work promotes both the electrochemical performance and mechanistic understanding of polyaniline to a new stage, towards practical application in energy storage devices as a low‐cost, high‐performance, sustainable, and green cathode material. [ABSTRACT FROM AUTHOR]

Anode‐less all‐solid‐state batteries (ASSBs) are being targeted for next‐generation electric mobility owing to their superior energy density and safety as well as the affordability of their materials. However, because of the anode‐less configuration, it is nontrivial to simultaneously operate the cell at room temperature and low pressure as a result of the sluggish reaction kinetics of lithium (de)plating and the formation of interfacial voids. This study overcomes these intrinsic challenges of anode‐less ASSBs by introducing a dual thin film consisting of a magnesium upper layer with a Ti3C2Tx MXene buffer layer underneath. The Mg layer enables reversible Li plating and stripping at room temperature by reacting with Li via a (de)alloying reaction with a low reaction barrier. The MXene buffer layer maintains the electrolyte‐electrode interface by inhibiting the formation of voids even at low pressure of 2 MPa owing to the high ductility of MXene. This study highlights the importance of a combined chemical and mechanical approach when designing anode‐less electrodes for practical adaptation for anode‐less ASSBs. [ABSTRACT FROM AUTHOR]

Exploring highly active and robust catalysts, which have low precious metal content, to boost the kinetically sluggish oxygen evolution reaction (OER) is a key concern for hydrogen production via proton exchange membrane water electrolysis (PEMWE). Here, rational engineering of the morphology and the local geometric ligand environment of Ir and Ru catalysts are presented by using defect‐rich, lanthanum‐ and lithium‐doped Co3O4 nanofiber (LLCF) as substrate that promotes the electrocatalytic OER. Two catalysts, IrCoOx@LLCF and RuCoOx@LLCF, achieve mass activities of 1013.5 A gIr−1 and 1911.4 A gRu−1 in 0.1 m HClO4 at 300 mV overpotential, respectively, which are 26 and 50 times higher than that of commercial IrO2 and RuO2. Operando X‐ray absorption spectroscopy unveils the reversible structure of IrCoOx during the OER and the suppression of over‐oxidation of Co and Ir, giving rise to high stability. Density functional theory calculations reveal that the local geometric ligand engineering optimizes the binding of oxygenated species to the active sites, resulting in strongly enhanced catalytic activity. [ABSTRACT FROM AUTHOR]

In recent decades, sodium‐ion batteries (SIBs) have received increasing attention because they offer cost and safety advantages and avoid the challenges related to limited lithium/cobalt/nickel resources and environmental pollution. Because the sodium storage performance and production cost of SIBs are dominated by the cathode performance, developing cathode materials with large‐scale production capacity is the key to achieving commercial applications of SIBs. Therefore, developing host materials with high energy density, long cycling life, low production cost, and high chemical/environmental stability is crucial for implementing advanced SIBs. Among the developed cathode materials for SIBs, O3‐type sodiated transition‐metal oxides have attracted extensive attention owing to their simple synthesis methods, high theoretical specific capacity, and sufficient Na content. However, the relatively large Na‐ion radius leads to sluggish diffusion kinetics and inevitable complex phase transitions during the deintercalation/intercalation process, resulting in poor rate capability and cycling stability. Therefore, this review comprehensively summarizes the research progress and modification strategies for O3‐type cathodes, including the component design, surface modification, and optimization of synthesis methods. This work aims to guide the development of commercial layered oxides and provide technical support for the next generation of energy‐storage systems. [ABSTRACT FROM AUTHOR]

In this study, a comprehensive quantitative analysis of the photodiode (PD) is conducted and photovoltaic (PV) characteristics of organic non‐fullerene PCE10:ITIC‐4F devices before and after exposure to a 150 ns pulse of 170 keV proton irradiation with the fluence of 2·1012 p cm−2 that is equivalent to ≈6 years of operation at a low Earth orbit. While an expected initial performance reduction happened in the photodiode and photovoltaic operation modes, a hitherto unknown self‐healing effect in the organic devices is observed several days after the proton irradiation. The organic bulk‐heterojunction (BHJ) material properties and the multi‐mechanisms recombination processes before and after irradiation and during self‐healing are investigated. This analysis provides a quantitative understanding of the changes occurring in the device physics and points toward the relevant aspects of the self‐healing mechanism related to the dynamics of proton‐induced traps in the bulk of the organic active layer. Ultimately, the synergy of record lightweight features and newly discovered self‐healing of proton‐induced damage in organic PDs and solar cells highlights their great potential for applications in rapidly emerging space technology. [ABSTRACT FROM AUTHOR]

The effect of Ru substitution on the structure and electrochemical properties of P2‐type Na0.67CoO2 is investigated. The first‐discharge capacities of Na0.67CoO2 and Na0.6 [Co0.78Ru0.22]O2 materials are 128 and 163 mAh g−1 (23.5 mA g−1), respectively. Furthermore, the rate capability is improved due to the electro‐conducting nature of Ru doping. Operando X‐ray diffraction analysis reveals that the Na0.67CoO2 does not undergo a phase transition; however, multiple Na+/vacancy ordered superstructures within the P2 phase appear during Na+ extraction/insertion. In contrast, the Na0.6[Co0.78Ru0.22]O2 material undergoes a P2–OP4 phase transition during desodiation, with no formation of Na+/vacancy ordering within the P2 phase. The increased discharge capacity of Na0.6[Co0.78Ru0.22]O2 is most likely associated with additional cationic Ru4+/Ru5+ redox and increased anionic O2−/(O2n−) redox participation. Combined experimental (galvanostatic cycling, X‐ray absorption spectroscopy, differential electrochemical mass spectrometry) and theoretical (density functional theory calculations) studies confirm that Ru substitution provokes the oxygen‐redox reaction and that partial O2 release from the oxide lattice is the origin of the reaction. The findings provide new insight for improving the electrode performance of cathode materials via 4d Ru substitution and motivate the development of a new strategy for the design of high‐capacity cathode materials for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Non‐fullerene acceptors (NFAs) have enabled power conversion efficiencies exceeding 19% in organic solar cells (OSCs). However, the open‐circuit voltage of OSCs remains low relative to their optical gap due to excessive non‐radiative recombination, and this now limits performance. Here, an important aspect of OSC design is considered, namely management of the triplet exciton population formed after non‐geminate charge recombination. By comparing the blends PM6:Y11 and PM6:Y6, it is shown that the greater crystallinity of the NFA domains in PM6:Y11 leads to a higher rate of triplet‐triplet annihilation (TTA). This is attributed to the four times larger ground state dipole moment of Y11 versus Y6, which improves the long range NFA out‐of‐plane ordering. Since TTA converts a fraction of the non‐emissive triplet states into bright singlet states, it has the potential to reduce non‐radiative voltage losses. Through a kinetic analysis of the recombination processes under 1‐Sun illumination, a framework is provided for determining the conditions under which TTA may improve OSC performance. If these could be satisfied, TTA has the potential to reduce non‐radiative voltage losses by up to several tens of millivolts. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide is an essential chemical that is attracting strong attention for energy and environmental applications. However, the struggle between the growing market demand and the unsustainability of the conventional anthraquinone method motivates the exploration of alternative H2O2 production processes. Although several new production processes have been proposed, the environmental‐friendly solar‐driven H2O2 production attracts most attention because of the only inputs of water, oxygen, and light energy. The rational design of functional photo‐responsive catalysts promotes H2O2 production in the photocatalytic and photoelectrocatalytic approaches. These are, in general, achieved by facilitating the preferential adsorption of key intermediates of OOH*/OH*/O*, enhancing the light absorption, promoting the charge separation, and accelerating the surface charge transfer with selective number of involved charges. This review systematically summarizes strategies for photo(electro)catalysts toward H2O2 production via both the water oxidation and oxygen reduction pathways. Though the oxygen reduction route is perceived as more popular in the community, selective water oxidation is emerging as a convincing alternative. Furthermore, prevailing hypotheses, state‐of‐the‐art catalysts, critical challenges, and perspectives are discussed in depth. This review aims to enhance the comprehension of this research field and promote interest in sustainable H2O2 production. [ABSTRACT FROM AUTHOR]

A confined electrical double‐layer (EDL) inside nanoporous electrodes has a large capacitance and deviates from traditional ones. Unfortunately, its capacitive mechanism is still unclear. Herein, expanded vertical graphene/diamond (EVG/D) films with regular and ordered 0.7‐nm layered channels are designed and synthesized to serve as an ideal model for understanding confined EDL. A clear overall picture of confined EDL is provided at an atomic resolution with the aid of in situ electrochemical Raman spectroscopy, electrochemical quartz crystal microbalance (EQCM), and density functional theory (DFT) calculations combined with three‐dimension reference interaction site method (3D‐RISM). It is especially interesting that the induced charges in electrode hosts are highly localized with a density far higher than that on a traditional EDL and even close to those of ion batteries. It is proposed that such a high localization of induced charges plays an essential role in the high energy storage efficiency of confined EDL capacitance. This work not only provides a previously unexplored way to refine the mechanism of confined EDL, but also further lays the foundation for understanding the functions of nanoporous or layered materials in electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Electrochemical cells that utilize metals (e.g., lithium, sodium, zinc) as anodes are under intense investigation as they are projected to replace the current lithium‐ion batteries to serve as a more energy‐dense option for commercial applications. In addition, metal electrodes provide opportunities for fundamental research of different phenomena, such as ion transport and electrochemical kinetics, in the complex environment of reactive metal‐electrodeposition. In this work, computationally and experimentally the competing effects related to transport and kinetics during the metal electrodeposition process are examined. Using Brownian dynamics simulations, it is shown that slower deposition kinetics results in a more compact and uniform Li morphology. This finding is experimentally implemented by designing ion‐containing polymeric coatings on the electrodes that simultaneously provide pathways for lithium‐ion transport, while impeding the charge transfer (Li+ + e− → Li) at heterogeneous surfaces. It is further shown that these ionic polymer interfaces can significantly extend the cell‐lifetime of a lithium metal battery in both ether‐based and carbonate‐based electrolytes. Through theoretical and experimental investigations, it is found that a low kinetic to transport rate ratio is a major factor in influencing the Li plating morphology. The plating morphology can be further fine‐tuned by increasing ionic conductivity. [ABSTRACT FROM AUTHOR]

A photoelectrochemical (PEC) water splitting device based on a dual‐junction monolithic tandem cell that utilizes NiOOH/FeOOH/BiVO4/SnO2/Ta:SnO2 (TTO)/tunnel oxide passivated contact (TOPCon) Si is reported. The PEC device achieves a maximum photocurrent density of 1.4 mA cm−2 (equal to a solar‐to‐hydrogen conversion efficiency of 1.72%) in 1.0 m potassium borate solution (pH 9) when illuminated with air mass 1.5 G simulated solar irradiation, which is the highest value among dual‐junction monolithic photoelectrochemical cells except for III–V materials. The TOPCon Si not only works as an appropriate bottom photoelectrode for subsequent high‐temperature BiVO4 processing but also offers a high photovoltage of 590 mV. Transparent and conductive TTO grown by pulsed laser deposition serves as a recombination layer to achieve effective integration. In addition, the TTO provides chemical and physical protection, allowing the surface of the TOPCon Si to exhibit 24 h of tandem cell stability under weak base electrolyte conditions. The SnO2 hole‐blocking layer inserted between TTO and BiVO4 enhances the charge separation of BiVO4, allowing the device to achieve high efficiency. Artificial leaf‐type monolithic tandem cells consisting of NiFe/BiVO4/SnO2/TTO/TOPCon Si/Ag/Ti/Pt with a solar‐to‐hydrogen efficiency of 0.44% are also demonstrated. [ABSTRACT FROM AUTHOR]

Recharging battery‐powered electric vehicles (EVs) in a similar timeframe as those used for refueling gas‐powered internal combustion vehicles is highly desirable for rapid penetration of the EV market. It is well known that the electrolyte in a battery plays a critical role in fast‐charging capability of the battery because it determines the rate of ion transport together with its derived electrode/electrolyte interphases on both cathode and anode of the battery. In this study, the effects of contents of salt, coordinating solvent, and noncoordinating diluent on salt dissociation degree and electrolyte ionic conductivity are investigated, and a controlled solvation structure electrolyte is developed to improve the lithium ion mobility and conductivity in the electrolyte and to enhance the kinetics and stability of the electrode/electrolyte interphases in the battery. This electrolyte enables fast‐charging capability of high energy density lithium‐ion batteries (LIBs) at up to 5 C rate (12‐min charging), which significantly outperforms the state‐of‐the‐art electrolyte. The controlled solvation structure sheds light on the future electrolyte design for fast‐charging LIBs. [ABSTRACT FROM AUTHOR]

Despite their ultrahigh specific capacity, lithium‐rich layered oxide cathodes are still plagued by challenges such as poor cycle stability and notorious voltage decay, which are primarily attributed to surface issues such as the release of lattice oxygen and interfacial side reactions. In this study, a facial strategy of gradient fluorination is adopted to construct a thin but robust LiF‐rich cathode electrolyte interface (CEI), highly enhancing the stability of the interface of lithium‐rich oxides. Experimental results and theoretical calculations both demonstrate that the stable CEI not only promotes oxygen participation in redox reactions and simultaneously inhibits oxygen release and structural transition, but also facilitates the transport kinetics of lithium ions. As a result, the gradient fluorinated lithium‐rich cathode delivers highly enhanced rate performance (133 mAh g−1 at 5 C), superior cycling stability with a capacity retention of 81.9% after 100 cycles at 1 C (250 mAh g−1), and alleviated voltage fade (only 1.75 mV per cycle). Moreover, a unique formation mechanism for LiF‐rich surfaces is proposed according to theoretical calculations. This work not only provides a fresh understanding of the CEI formation mechanism, but also show a promising avenue for designing LiF‐rich CEIs applicable to other layered oxide cathodes. [ABSTRACT FROM AUTHOR]

Microcavity resonance is an effective technique for making promising semitransparent organic photovoltaics (ST‐OPVs) even more aesthetically attractive with high color saturation, by tailoring the visible transmittance spectrum to narrow the transmission peak. In this study, a distinctive microcavity resonance color filter (CF) structure of silver/ bismuth(III) fluoride /silver (Ag/BiF3/Ag) is integrated upon the rear transparent electrode, which simultaneously achieves high color purity and high power conversion efficiency (PCE) for colorful OPVs. By precisely regulating the thickness of the BiF3 layer, colorful OPVs with a wide color gamut and high color purity are achieved, including the colors of indigo, blue, bluish‐green, green, orange, and red, as well as compound color devices with dual or multiple transmission peaks in the visible region. A recorded PCE of 16.27% is obtained for the indigo OPV, with the Commission Internationale de l´Eclairage 1931 coordinates of (0.164 and 0.087) and a maximum transmittance of 18.7% at the transmission peak wavelength of 393 nm. Furthermore, colorful OPVs as color reflectors are systematically investigated under different light incident surfaces. The improved stability of colorful OPVs is attributed to the excellent moisture resistance of BiF3. The colorful OPVs with desired transmitted/reflected colors, and wide color gamut show great potential for future energy harvesting solutions. [ABSTRACT FROM AUTHOR]

Ti3C2Tx MXene has shown remarkable potential for supercapacitors. However, its limited capacitance restrains the energy density. Here, a designed redox‐electrolyte strategy boosted with electrode engineering for Ti3C2Tx MXene is demonstrated, by which a record‐high specific capacitance of 788.4 F g−1 at 2 mV s−1 is achieved, accompanied by good rate capability and highly improved cyclic stability compared with the pristine MXene electrode. For the first time, redox additives with redox potentials falling in the Ti3C2Tx MXene's potential range and that can take full advantage of the characteristics of Ti3C2Tx MXene are investigated. CuSO4 and VOSO4 are screened as the hybrid redox additives; and it is revealed that copper and vanadium ions can bond with ═O terminals on the MXene surface and undergo redox reactions mainly via Cu2+/Cu+ and V3+/V2+. The electrode engineering significantly boosts the designed redox‐electrolyte strategy by enhancing ion dynamics and increasing electrochemically active sites. High energy density of 80.9 Wh kg−1 at a power density of 376.0 W kg−1 and high cyclic stability and improved self‐discharging behavior are obtained for the fabricated supercapacitor by applying this strategy. The strategy is also demonstrated for the performance improvement of MXene‐based flexible supercapacitors with hydrogel electrolytes. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries are promising grid‐scale energy storage devices because of their affordability, operational safety, and environmental benignity. Among these, Zn‐ion batteries (ZIBs) have unfolded new horizons. Designing superior cathodes for ZIBs is crucial. Covalent organic frameworks (COFs) can be made redox active with a high storage surface. Here, for the first time, a chelating COF with redox‐active ZnI2 in a ZnSO4(aq) electrolyte is combined. Including iodide harvests an approximately threefold enhancement in capacity from 208 to 690 mAh g−1 at 1.5 A g−1, the highest among all the COF‐derived ZIBs. Remarkably, a charge–discharge curve at 1.3 V exhibits very limited dropout voltage and super‐flat platform, with a remarkable capacity of 600 mAh g−1 at 5 A g−1 stable up to 6000 cycles, confirming that the polyiodide generation and storage are sustainable. The COF's dual‐ion storage (Zn2+ and polyidode) delivers a ZIB with the highest energy density. Spectro‐electrochemical measurements coupled with X‐ray photoelectron spectroscopy unambiguously unveil the existence of multiple polyiodide species, with I3− and IO3− ions as the prominent species. The latter gets reduced at the COF electrode under an applied potential, leaving I3− as the major species stored on the COF. The prospect of COF‐polyiodide(aq) is a windfall for metal‐ion batteries. [ABSTRACT FROM AUTHOR]

Humidity control is relevant to many processes in buildings and manufacturing and is responsible for over 600 million tons of CO2 annually. As such, desiccants that can efficiently remove moisture from air can greatly reduce emissions. A new class of desiccant materials, thermo‐responsive desiccants, has been of increased interest in the literature. These materials are generally based on thermo‐responsive polymers and exhibit a temperature‐dependent isotherm, an attribute that is small in traditional desiccants. In this work, seven key parameters needed to create an effective thermo‐responsive polymer desiccant are identified using a combination of modeling and experimental data. It is found that more thermo‐responsiveness is not necessarily better for energy efficiency, and that an optimal, "medium" value is desired. Additionally, polymer composition and architecture play key roles in adjusting the seven key parameters. Finally, based on findings from both modeling and experimental work, guidelines on synthesizing future thermo‐responsive polymer desiccants are presented. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbX3 (X = I, Br, Cl or their mixtures) perovskites attract enormous attention in recent years due to their excellent optoelectronic properties, outstanding thermal/light stability, and wide range of applications in electronic devices. Encouragingly, the reported power conversion efficiency of CsPbX3 perovskite solar cells (PSCs) rockets up from 2.9% in 2015 to the present 21.0%. In order to further promote the performance of CsPbX3 PSCs toward the Shockley–Queisser efficiency limit, it is important to optimize the quality of perovskite films by crystallization kinetics modulation and defect suppression. In this review, first, some fundamental information about all‐inorganic CsPbX3 perovskites is briefly introduced, including the crystallization mechanism, growth mode, crystal structure, and phase stability as well as possible defects and their effects on device performance. Second, the recent exciting progress of the crystallization modulation strategies for high‐quality CsPbX3 films is summarized and discussed in detail. The advantages of different strategies, including annealing engineering, solvent engineering, precursor engineering, composition engineering, and interface engineering, are highlighted. Finally, methods for improving the efficiency of inorganic PSCs are discussed, and the future development prospects of inorganic PSCs are also outlined. [ABSTRACT FROM AUTHOR]

Metal halide perovskite solar cells (PSCs) have become one of the most promising next‐generation photovoltaic technologies due to their low‐cost fabrication, solution processability, and superior optoelectronic properties. Although state‐of‐art PSCs demonstrate a power conversion efficiency record comparable to that of silicon solar cells, there are still many challenges toward commercialization. PSCs are devices based on various semiconductor heterojunctions that all play important roles in device performance. The device operation relies on a combination of multiple heterojunctions to offer a delicate control of photocarrier generation, separation, and transport to respective electrodes. Hence, advanced heterojunction design in PSCs is crucial for the further improvement of device performance. Notably, the conversion efficiency records for PSCs are mainly ascribed to optimized heterojunction engineering. Considering the significance of this topic, a comprehensive review of the recently developed heterojunction designs is presented. Following a brief introduction to PSC architectures, operation, and fundamental heterojunction design theories, the recent progress on perovskite/electron transport layer, perovskite/hole transport layer, and perovskite/perovskite heterojunction engineering is elaborated. Finally, conclusions and perspectives on this research field are addressed. [ABSTRACT FROM AUTHOR]

The success of liquid/solid‐state batteries is fundamentally determined by the electrode microstructures, which is particularly true for high‐energy‐density electrodes with either thick configuration or high‐capacity active materials. Unfortunately, high‐energy‐density electrodes usually suffer from fast performance degradation due to various challenging issues in microstructures. Therefore, a better understanding of electrode microstructures and the strategies toward optimizing them are in urgent need by the research community and battery industries. In this review, the authors attempt to rethink and comprehensively understand the multiscale microstructures for particularly thick electrodes and to summarize the corresponding structuring strategies. Specifically, in analogy to proteins, the multiscale electrode microstructures are classified into the primary structures of rigid building blocks, the secondary structures of active material microenvironment, and the tertiary structures of electrode architectures. Meanwhile, the design principles and structuring strategies at different levels of microstructures are detailed with consideration given to efficiency, energy consumption, eco‐friendliness, and scalability. Finally, a concept of a battery manufacturing genome based on structuring strategy profile (similar to amino acid profile) is proposed as the forthcoming opportunity for the future connection of machine learning with battery microstructure optimization, which may promote the development of next‐generation on‐demand batteries. [ABSTRACT FROM AUTHOR]

The electrification of transportation in the past few decades has sparked the retirement of lithium‐ion batteries (LIBs) which hinders sustainability derived from environmental impact and valuable elements loss through improper disposal. The challenges of recycling spent LIB are contamination, complicated processes, massive chemical/energy consumption, and secondary pollution. Here, a material and energy dual circulations method is proposed for a closed‐loop and sustainably recycling the components in spent LIBs. In the material circulation, the cathode, anode, and the accessories, like castings, aluminum‐plastic films, and binders, are recycled by electrochemical dual‐electrode recycling technology to regenerate LIBs and fabricate a triboelectric nanogenerator (TENG). In energy circulation, the fabricated TENG converts ambient wind energy into electricity to continuously power the material circulation by forming a self‐powered system. This system shows high element selectivity (Li, 99.7%; Ni, 96.1%; Co, 97.3%; and Mn, 97.2%), self‐powering, a simplified treating procedure, and high profit, which makes it feasible for commercial application. [ABSTRACT FROM AUTHOR]

Exceeding the energy density of lithium−carbon monofluoride (Li−CFx), today's leading Li primary battery, requires an increase in fluorine content (x) that determines the theoretical capacity available from C−F bond reduction. However, high F‐content carbon materials face challenges such as poor electronic conductivity, low reduction potentials (<1.3 V versus Li/Li+), and/or low C−F bond utilization. This study investigates molecular structural design principles for a new class of high F‐content fluoroalkyl‐aromatic catholytes that address these challenges. A polarizable conjugated system—an aromatic ring with an alkene linker—functions as electron acceptor and redox initiator, enabling a cascade defluorination of an adjacent perfluoroalkyl chain (RF = −CnF2n+1). The synthesized molecules successfully overcome premature deactivation observed in previously studied catholytes and achieve close‐to‐full defluorination (up to 15/17 available F), yielding high gravimetric capacities of 748 mAh g−1fluoroalkyl‐aromatic and energies of 1785 Wh kg−1fluoroalkyl‐aromatic. The voltage compatibility between fluoroalkyl‐aromatics and CFx enables design of hybrid cells containing C−F redox activity in both solid and liquid phases, with a projected enhancement of Li–CFx gravimetric energy by 35% based on weight of electrodes+electrolyte. With further improvement of cathode architecture, these "liquid CFx" analogues are strong candidates for exceeding the energy limitations of today's primary chemistries. [ABSTRACT FROM AUTHOR]

Constructing and manipulating hetero‐interfaces for the electrocatalytic hydrogen evolution reaction (HER) is highly desirable, but still poses a significant challenge. Herein, this work adopts a facile way to controllably synthesize three different hetero‐interfaces by anchoring ultrafine Ru nanoparticles on various MoOx nanotube (NT) substrates, including MoO2, MoO2/MoO3, and MoO3. Remarkably, MoO2@Ru NT displays excellent HER activity with tiny overpotentials of 89 and 131 mV delivering large current densities of 500 and 1000 mA cm−2, respectively, far surpassing two other hetero‐interfaces, commercial Ru/C, Pt/C catalysts. Impressively, this hetero‐interface even achieves an exceptionally large current density of 4000 mA cm−2 at an overpotential of 322 mV. Moreover, MoO2@Ru NT presents exceptional stability for at least 100 h at 1000 mA cm−2 with negligible degradation. Both experimental observations and theoretical calculations suggest that moderate electron transfer from Ru to MoO2 enhances the water dissociation kinetics, and optimizes the hydrogen adsorption/desorption, thus simultaneously speeding up the HER kinetics. Furthermore, an anion exchange membrane electrolyzer assembled by obtained MoO2@Ru NT as a cathode electrocatalyst, shows attractive activity and excellent durability, with a low voltage of 1.78 V at 1000 mA cm−2, and a prolonged time period for 200 h at 1000 mA cm−2. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) cathodes can host diverse monovalent and multivalent metal ions due to their tunable structure. However, their electrochemical performance suffers from poor cycle life associated with chemo‐mechanical instabilities. This study investigates the driving forces behind chemo‐mechanical instabilities in Ni‐ and Mn‐based PBAs cathodes for K‐ion batteries by combining electrochemical analysis, digital image correlation, and spectroscopy techniques. Capacity retention in Ni‐based PBA is 96% whereas it is 91.5% for Mn‐based PBA after 100 cycles at C/5 rate. During charge, the potassium nickel hexacyanoferrate (KNHCF) electrode experiences a positive strain generation whereas the potassium manganese hexacyanoferrate (KMHCF) electrode undergoes initially positive strain generation followed by a reduction in strains at a higher state of charge. Overall, both cathodes undergo similar reversible electrochemical strains in each charge–discharge cycle. There is ~0.80% irreversible strain generation in both cathodes after 5 cycles. XPS studies indicated richer organic layer compounds in the cathode‐electrolyte interface (CEI) layer formed on KMHCF cathodes compared to the KNHCF ones. Faster capacity fades in Mn‐based PBA, compared to Ni‐based ones, is attributed to the formation of richer organic compounds in CEI layers, rather than mechanical deformations. Understanding the driving forces behind instabilities provides a guideline to develop material‐based strategies for better electrochemical performance. [ABSTRACT FROM AUTHOR]

Aqueous redox flow batteries (RFBs) have attracted significant attention as energy storage systems by virtue of their inexpensive nature and long‐lasting features. Although all‐vanadium RFBs exhibit long lifetimes, the cost of vanadium resources fluctuates considerably, and is generally expensive. Iron–chromium RFBs take advantage of utilizing a low‐cost and large abundance of iron and chromite ore; however, the redox chemistry of CrII/III generally involves strong Jahn–Teller effects. Herein, this work introduces a new Cr‐based negolyte coordinated with strong‐field ligands capable of mitigating strong Jahn–Teller effects, thereby facilitating low redox potential, high stability, and rapid kinetics. The balanced full‐cell configuration features a stable lifetime of 500 cycles with energy density of 14 Wh L−1. With an excessive posolyte, the full‐cell can attain a high energy density of 38.6 Wh L−1 as a single electron redox process. Consequently, the proposed system opens new avenues for the development of high‐performance RFBs. [ABSTRACT FROM AUTHOR]

Li(NixCoyMnz)O2 (x + y + z = 1, NCM), as one of the most dominant cathode materials in electric vehicle (EV) batteries, faces the challenges of poor cycling stability and safety concerns with the increase of Ni content and charge/discharge capacity. Single crystalline NCM (SC‐NCM) materials have been developed to mitigate these challenges, owing to their lower surface areas, fewer grain boundaries, and better morphological stability. Here, the preparation strategies of SC‐NCM are summarized, including continuous high‐temperature sintering (CHTS), molten salt method, pulse high‐temperature sintering (PHTS), and controllable growth with special orientations or sizes. CHTS produces irregular SC‐NCM particles, but is accompanied by Li‐volatilization and agglomeration during long‐term sintering. The molten salt helps to lower calcination temperature and generate well‐defined crystalline material, but generally causes large capacity loss due to the Li/H exchange in the following water rinsing procedure. To address the above challenges, the PHTS strategy has recently been recently proposed, which mitigates Li‐loss through shortened high‐temperature stage and avoids further water rinsing steps. For improving the C‐rate performance, controllable crystal growth with specific sizes and crystal orientations is highly desired, which calls for further investigation and upgrading of current large‐scale preparation technology. [ABSTRACT FROM AUTHOR]

Reversibility, usually evaluated by Coulombic efficiency (CE) and limited by dendrite growth, has become the major roadblock toward the widespread commercialization of zincion batteries. Tailoring the Zn deposition behavior is vital to prevent dendrite growth. In this work, the facet‐terminator serine is introduced to modulate the interface and obstruct the rampant growth of the Zn (100) plane. The serine cation (Ser+) is revealed to preferentially adsorb onto the electrode/electrolyte interface, suppressing the interfacial parasitic reaction. Theoretical analysis and postmortem/operando experimental techniques indicate that the Ser+ bestows (100)‐dominated morphology to zinc anodes, enabling a highly reversible and dendrite‐free Zn anode. These features endow the Zn anode with a long cyclic life of more than 800 h for Zn//Zn batteries and a high average Coulombic efficiency of 99.8% at 5 mA cm−2 and 5 mAh cm−2 for Zn//Cu batteries. When assembling with commercial V2O5, the full battery delivers a high capacity of 345.1 mAh g−1 at 5 A g−1 with a retention of 74.1% over 2000 cycles. [ABSTRACT FROM AUTHOR]

The use of a sacrificial cathode additive that contains a large amount of lithium is one potential solution to compensate for the irreversible capacity loss associated with next‐generation anodes such as silicon. Antifluorite‐type Li6CoO4 has attracted attention as a potential cathode additive owing to its remarkably high theoretical lithium extraction capacity. However, the complex mechanism of lithium extraction as well as the oxygen loss from Li6CoO4 is not well understood. A generalizable computational thermodynamics and experimental framework is presented to understand the lithium‐extraction pathway of Li6CoO4. It is found that one lithium per formula unit can be topotactically extracted from Li6CoO4, followed by an irreversible and nontopotactic phase transformation to Li2CoO3 or LiCoO2 depending on the temperature. The results show that peroxide species may form to charge‐compensate for Li extraction which is undesirable as this can lead to gas release during battery operation. It is suggested that charging Li6CoO4 at an elevated temperature that the electrolyte can withstand, redirects the reaction pathway and prevents the formation of intermediate peroxide species making it an effective and stable sacrificial cathode additive. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries (ASSBs) are rapidly moving toward commercialization as a promising high‐performance energy storage device for portable electronics and electric vehicles. One of the most challenging problems hindering the industrialization of ASSBs is the lack of technologies for cost‐effective and large‐scale manufacturing of high‐quality solid‐state electrolytes (SSEs) with about the same thickness as the polymer separators in conventional lithium‐ion batteries. Herein, atmospheric plasma spraying (APS) is adopted as a practical route to process large‐scale, uniform, and thin SSEs to conduct Li‐ions and further to manufacture ASSBs. Garnet‐type Li7La3Zr2O12 (LLZO) films with thicknesses ranging from 30 to 300 µm are successfully manufactured with direct APS technique followed with a post annealing treatment. The electrolyte reaches a high Li‐ion conductivity of 3.82 × 10−5 S cm−1 at room temperature (25 °C). Additionally, the LLZO film with a thickness of 300 µm shows a flexural strength of 157 MPa. Li/LLZO/Li and Li/LLZO/LiFePO4 cells are assembled with the films, both showing stable cycling performance. The APS method shows scalability in solid‐state electrolyte film production, and most importantly, such a process is highly compatible with the current battery industry. [ABSTRACT FROM AUTHOR]

Several classes of materials manifest displacive phase transitions, including shape memory alloys, many electronically correlated materials, superconductors, and ferroelectrics. Each of these classes of materials displays a wide range of fascinating properties and functionalities that are studied in disparate communities. However, these materials' classes share similar electronic and phononic instabilities in conjunction with microstructural features. Specifically, the common motifs include twinned microstructures, anomalies in the transport behavior, softening of specific phonons, and frequently also (giant) Kohn anomalies, soft phonons, and/or nesting of the Fermi surface. These effects, phenomena, and their applications have until now been discussed in separate communities, which is a missed opportunity. In this perspective a unified framework is presented to understand these materials, by identifying similarities, defining a unified phenomenological description of displacive phase transitions and the associated order parameters, and introducing the main symmetry‐breaking mechanisms. This unified framework aims to bring together experimental and theoretical know‐how and methodologies across disciplines to enable unraveling hitherto missing important mechanistic understanding about the phase transitions in (magnetic) shape memory alloys, superconductors and correlated materials, and ferroelectrics. Connecting structural and electronic phenomena and microstructure to functional properties may offer so‐far unknown pathways to innovate applications based on these materials. [ABSTRACT FROM AUTHOR]

Although there are various strategies for solid‐state polymer lithium batteries (SSPLBs) manufacturing, the most promising is the in situ polymerization process. The in situ polymerization process inherits good liquid electrolyte/electrode interfacial contact and is compatible with existing lithium‐ion batteries manufacturing processes, making it easy to achieve scale‐up production. However, most of the current studies on the in situ polymerization process are based on lab‐level coin cells, while practical pouch cells are much less studied. There is a huge difference between lab‐level coin SSPLBs and practical pouch SSPLBs. Here, as a complement to the existing reports and reviews, a systematic review of the challenges and design principles of in situ polymerization process for fabricating practical pouch SSPLBs is provided to enable a comprehensive understanding and strategic guidance for practical SSPLBs applications. This review thoroughly discusses recent advances regarding the fabrication of SSPLBs using in situ polymerization process and presents the existing challenges and future outlook for the fabrication of practical SSPLBs by in situ polymerization processes. Furthermore, the critical issues of electrode materials for manufacturing practical SSPLBs are highlighted during the in situ polymerization process, and an attempt is made to call more attention to the performance of the practical pouch SSPLBs. [ABSTRACT FROM AUTHOR]

Co shows excellent performance in the high voltage range for layered oxide cathode materials for sodium ion batteries (SIBs). However, its high cost and toxicity are significant disadvantages.Co‐free cathodes with high performance are urgently needed for development. Herein, cheap Mg and Ti elements are preferred to replace Co elements. A P2‐Na0.67Mn0.53Ni0.30Mg0.085Ti0.085O2 (Ni30MgTi) cathode shows a high reversible specific capacity of 118 mA h g−1 at a current density of 50 mA g−1 in 2.0–4.25 V, which is even higher than that in the base sample with Co. Moreover, Mg and Ti raise the median discharge voltage from 3.21 to 3.59 V, which raises the energy density from 325 to 410 Wh kg−1. On the other hand, ex situ XPS and in situ differential electrochemical mass spectrometry tests indicate that Ni30MgTi has a stable anionic redox reaction with reversible capacity in the high voltage range. The concept of bimetallic co‐substitution offers a simple and effective Co‐free strategy to reduce the cost and increase the energy density of layered oxide cathode materials simultaneously for SIBs. [ABSTRACT FROM AUTHOR]

The tribovoltaic effect is the direct‐current (DC) output that results from sliding a p‐type semiconductor on top of an n‐type semiconductor, and it is caused by the electron–hole pairs generated However, the rigid structure of traditional semiconductor limits its potential application in wearable fields. Here, p–type and n–type fabric with semiconductor properties are prepared by doping small organic molecules of cetyltrimethylammonium bromide and sodium dodecylbenzene sulfonate on the carbon atoms of single–wall carbon nanotubes (SWCNTs), and three all‐fabric direct‐current triboelectric nanogenerators based on the tribovoltaic effect (AFDC‐TENG) are developed , which exhibit high flexibility, satisfactory comfort, and stable DC output. In addition, the effects of structural parameters and environmental factors on the electrical output of AFDC‐TENG are systematically discussed. The output voltage, current, and power density of p‐type AFDC‐TENG can reach 0.2 V, 0.29 µA, and 45.5 mV m−2 at a maximum speed of 0.2 m s−1 and a sliding frequency of 1 Hz, respectively. This work proposes a simple and scalable design form for all‐fabric DC power supply devices, which has potential applications in the future micro/nano energy or self‐powered flexible sensors. [ABSTRACT FROM AUTHOR]

The lack of highly efficient photoanodes presents a significant challenge to implementing the promising strategy of unbiased solar‐to‐fuel conversion. To achieve high‐performance photoanodes, improving their light harvesting and charge separation/injection capabilities is indispensable. Herein, solution‐processed vertically oriented Sb2S3 nanorod arrays on substrate are obtained via a Au seed layer, resulting in improved optoelectronic properties (due to the light scattering effect) and favorable crystallographic orientation of the 1D nanostructure. Moreover, the (NH4)2WS4 treatment caps the surface of the nanorods with an amorphous WSx layer and passivates the sulfur vacancy of Sb2S3, resulting in boosted charge extraction to the reactants. The resulting photoanode is employed to drive an iodide oxidation reaction (IOR), which is a prominent alternative to sluggish water oxidation reactions, exhibiting a high photocurrent density of 13 mA cm−2 at 0.6 V versus the reversible hydrogen electrode. Subsequently, an unassisted hydrogen generation device is demonstrated by combining an Sb2S3 nanorod array‐based photoanode for IOR and a perovskite‐based photocathode for the hydrogen evolution reaction, achieving an efficient hydrogen production current density of 5.7 mA cm−2 without any external bias. [ABSTRACT FROM AUTHOR]

High‐performance electrochemical applications have expedited the research in high‐power devices. As such, supercapacitors, including electrical double‐layer capacitors (EDLCs) and pseudocapacitors, have gained significant attention due to their high power density, long cycle life, and fast charging capabilities. Yet, no device lasts forever. It is essential to understand the mechanisms behind performance degradation and aging so that these bottlenecks can be addressed and tailored solutions can be developed. Herein, the factors contributing to the aging and degradation of supercapacitors, including electrode materials, electrolytes, and other aspects of the system, such as pore blocking, electrode compositions, functional groups, and corrosion of current collectors are examined. The monitoring and characterizing of the performance degradation of supercapacitors, including electrochemical methods, in situ, and ex situ techniques are explored. In addition, the degradation mechanisms of different types of electrolytes and electrode materials and the effects of aging from an industrial application standpoint are analyzed. Next, how electrode degradations and electrolyte decompositions can lead to failure, and pore blocking, electrode composition, and other factors that affect the device's lifespan are examined. Finally, the future directions and challenges for reducing supercapacitors' performance degradation, including developing new materials and methods for characterizing and monitoring the devices are summarized. [ABSTRACT FROM AUTHOR]

The Artificial Intelligence of Things (AIoT) connects everything with intelligence, while the increase in energy consumption generated by numerous electronic devices puts forward an impending demand on the power supply. Energy harvesting technology has emerged as a compelling innovation technology for the net zero emissions of the power supply for the AIoT. Although significant advances have been witnessed in energy harvesting, some issues such as poor electrical output, weak environmental adaptability, and low reliability are difficult to satisfactorily resolve. Mechanical intelligent energy harvesting can be defined as the system identifying the external excitation or its own state and reacting to it, rather than relying on electrical sensing elements or a central controller for certain adaptive or programmed functions. The adaptive and programmed functions exhibit great potential in solving the above‐mentioned issues that seriously restrict the development of the energy harvesting technology. Here, a generalized definition of mechanical intelligent energy harvesting is given critically and the design methodology is elaborated. The typical reported energy harvesting systems with the characteristics of mechanical intelligence are reviewed. The key research directions in mechanical intelligent energy harvesting are discussed. The mechanical intelligence is expected to revolutionize the development of the energy‐harvesting technology and pave the way for applications. [ABSTRACT FROM AUTHOR]

Copyright of Advanced Energy Materials is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Nb doping of Li[Ni0.855Co0.13Al0.015]O2 (NCA85) modifies its primary particle morphology to allow precise tailoring of its microstructure. The Nb dopant (1 mol%) elongates the primary particles and aligns them in the radial direction, creating a configuration that effectively dissipates the abrupt internal strain caused by H2↔H3 phase transitions near the charge end. The negation of the internal strain substantially improves the long‐term cycling stability achieved by the Nb‐doped NCA85 cathode; it retains 90% of its initial capacity after 1000 cycles while an undoped cathode retains 57.3%. Moreover, the enhanced mechano‐chemical stability of the Nb‐doped NCA85 cathode enables fast charging; accordingly, the Nb‐doped NCA85 cathode cycles stably for 500 cycles even when charged at 3 C (full charge is achieved in 20 min). The Nb‐doped cathode also demonstrates enhanced chemical and structural stability during calendar aging and under thermal load. The simple strategy of introducing Nb ions during the lithiation of NCA85, proposed in this paper, represents an effective solution that guarantees sufficient battery life, fast charging, and safety without compromising battery capacity for next‐generation electric vehicles. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) can convert a mechanical energy input to an electric energy output through Maxwell's displacement current. By increasing the electrical output and overcoming the mechanical limitations of TENGs, such devices can be used as an auxiliary power source for portable electronics. Nevertheless, the generation mechanism and structure must be optimized to compensate for the electrical and mechanical limitations of TENGs. This paper reports on a nonpolar liquid lubricant submerged TENG (LLS‐TENG), which can overcome the existing electrical and mechanical limitations of the TENG. When a nonpolar liquid lubricant is filled in the LLS‐TENG, the air breakdown can be effectively blocked owing to the large Debye length of such lubricants. In addition, the rolling friction and lubrication present in the LLS‐TENG can significantly reduce the friction wear of the device. Consequently, the LLS‐TENG can charge a commercial capacitor and battery by generating a high voltage and current output of up to 200 V and 170 mA, respectively. [ABSTRACT FROM AUTHOR]

Synthesizing active and durable catalysts for the hydrogen evolution reaction (HER) is of great significance for the development of a sustainable hydrogen economy. In this paper, an OsOx quantum dot loaded in 3D flexible graphdiyne is reported for photoelectrocatalysis, which shows greatly improved HER activity under light induction. The calculated and experimental results indicate graphdiyne (GDY) is not only used as the hole transfer layer to prevent hole–electron recombination, but can induce charge transfer for more high‐coordination osmium (Os4+). Upon exposure to a Xe lamp, OsOx QDs/GDY shows greatly enhanced catalytic activities and stabilities under alkaline conditions. Significantly, GDY can promote the good distribution and stability of metal oxide quantum dots. The fundamental advantage of the OsOx QDs/GDY catalyst is to promote hole transport and generate a large number of active sites and its superior photocurrent performance and photo/electrocatalytic activity. Simultaneously, due to the unique properties of the internal electronic structure of the GDY, the Mott‐Schottky effect is promoted efficiently and as a typical semiconductor catalyst, OsOx QDs/GDY shows unparalleled performance. [ABSTRACT FROM AUTHOR]

Colloidal quantum dot solar cells (QDSCs) are promising candidates amongst third generation photovoltaics due to their bandgap tunability, facile low‐temperature ink processing, strong visible‐to‐infrared absorption, and potential for multiple‐exciton generation. An unprecedented increase in power conversion efficiency is reported for different types of QDSCs in the last few years, making them appealing for large‐scale fabrication. The stability of QDSCs, however, still remains inadequate for industrial application, especially when they are operated under a sun‐like illumination in an ambient atmosphere. This review focuses on three classes of QDs (lead chalcogenides, lead halide perovskites, and lead‐free QDs) and considers the current understanding of their degradation mechanisms. For each material class, strategies for stability improvement are discussed, both from materials science and device engineering perspectives. This paper concludes by suggesting a methodology for characterizing the QDSCs' stability which would standardize the results obtained by researchers worldwide. [ABSTRACT FROM AUTHOR]

Partial shading of a solar module can induce a set of cells within the module to operate under reverse bias. Studies have shown that metal halide perovskite solar cells with a wide variety of compositions and contacts exhibit interesting behavior in reverse bias that includes both reversible performance loss and non‐reversible degradation. In this paper, an advanced drift‐diffusion approach incorporating an electrochemical term to explain the short‐circuit, open circuit and fill factor losses that are experimentally measured after prolonged reverse bias is used. It is shown that holes can tunnel into the perovskite due to sharp band bending near the contact, accumulate within the bulk of the perovskite absorber, and trigger the oxidation of halides to form neutral halogens. The density of neutral halogens is much higher in reverse bias because there are hardly any electrons available to reduce the iodine. The resulting halogens act as bulk recombination centers. While the interstitial halogen density does decay when the cell is operated in forward bias, permanent degradation can occur if the iodine diffuses out of the perovskite layer. Finally, the ways in which changing parameters such as the mobile ion density or the series resistance at the contact can influence device performance and stability are discussed. [ABSTRACT FROM AUTHOR]

The remarkable surge in energy demand has compelled the quest for high‐energy‐density battery systems. The Li–O2 battery (LOB) and Li–air battery (LAB), owing to their extremely high theoretical energy density, have attracted extensive research in the past two decades. The commercial development of LOB is hampered due to the numerous challenges its components present. Ionic liquids (ILs) are considered potential electrolyte solvents of LOBs and LABs due to their excellent electrochemical stability, thermal stability, non‐flammability, low flammability, and O2 solubility. In addition to electrolyte solvents, ILs also have other applications in LOB and LAB systems. This review reports the progress of IL‐based LOBs and LABs over the years since treported for the first time in 2005. The impact of the physiochemical properties of ILs on the performance of LOB and LAB at various operating conditions is thoroughly discussed. The various methodologies are also summarized that are employed to tune ILs' physiochemical properties to render them more favorable for rechargeable lithium batteries. Tunable properties of ILs create the possibility of designing cost‐effective batteries with excellent safety, high energy density and high power density, and long‐term stability. [ABSTRACT FROM AUTHOR]

The evolution of high‐energy‐density lithium‐ion batteries (LIBs) urgently requires the development of high‐safety electrolytes with high voltage resistance. Here, noncoordinating flame retardant pentafluoro‐(phenoxy)‐cyclotriphosphazene (FPPN) endows propylene carbonate (PC, 70 vol%)‐based electrolytes with high graphite anode compatibility, non‐flammability, high voltage stability, and excellent separator/electrode wettability. Theoretical calculations reveal that FPPN significantly affects Li+‐PC‐anion interactions and favors Li+ desolvation. Based on in situ optical microscopy and in situ differential electrochemical mass spectrometry, it is innovatively proposed that large amounts of H2 and C3H6 from PC decomposition play a dominant role in destroying the graphitic structure. The evolution of H2 and C3H6 is dramatically alleviated and totally suppressed, respectively, when FPPN prevents PC‐induced graphite exfoliation. More encouragingly, an optimized PC/FPPN‐based electrolyte (70 vol% PC) enables a high voltage LiCoO2/graphite pouch cell (4.35 V, ≈2.6 Ah, ≈242 Wh kg−1) with excellent cycle life and high safety. This work deepens the understanding of PC‐graphite compatibility and opens a new avenue of realizing practical application of PC‐based electrolytes (PC content over 50 vol%) in high capacity (over 2 Ah) LIBs. [ABSTRACT FROM AUTHOR]