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In situ formed gel polymer electrolytes (GPEs) have advantages in safety and adaptability to current high‐voltage lithium‐ion batteries (LIBs). However, it is challenging for GPEs to achieve stable cycling at high current densities. A flexible framework is proposed for stable in situ GPE, by introducing ─CF3 groups to the polymer network to establish rapid Li+ transport channels, and incorporating secondary amine N─H groups to anchor anion. The obtained GPE exhibits a high ionic conductivity of 2.6 mS cm−1 and a high Li+ transference number of 0.67. The assembled Li||NCM811 cell demonstrates excellent rate performance, with a discharging capacity of 112.3 mAh g⁻¹ at 10C, and capacity retention of 87.6% after 260 cycles at 1C. Furthermore, the assembled graphite||NCM811 cell demonstrates excellent long‐term cycling stability with impressive capacity retention of 73.2% after 300 cycles 3C (1.8 mA cm−2). This work presents a promising approach to enhancing the cycling stability of GPEs for high‐voltage LIBs at high current density. [ABSTRACT FROM AUTHOR]

High‐current‐density water electrolysis is considered a promising technology for industrial‐scale green hydrogen production, which is of significant value to energy decarbonization and numerous sustainable industrial applications. To date, substantial research advancements are achieved in catalyst design for laboratory‐based water electrolysis. While the designed catalysts demonstrate remarkable performance at laboratory‐based low current densities, they suffer from marked deteriorations in both activity and long‐term stability under industrial‐level high‐current‐density operations. To provide a timely assessment that helps bridge the gap between laboratory‐scale fundamental research and industrial‐scale practical water electrolysis technology, here the current advancements in various commercial water electrolyzers are first systematically analyzed, then the key parameters including work temperature, current density, lifetime of stacks, cell efficiency, and capital cost of stacks are critically evaluated. In addition, the impact of high current density on the electrocatalytic behavior of catalysts, including intrinsic activity, long‐term stability, and mass transfer, is discussed to advance the catalyst design. Therefore, by covering a range of critical issues from fundamental material design principles to industrial‐scale performance parameters, here the future research directions in the development of highly efficient and low‐cost catalysts are presented and a procedure for screening laboratory‐designed catalysts for industrial‐scale water electrolysis is outlined. [ABSTRACT FROM AUTHOR]

CeF 3 -NiFeLDH electrocatalyst enables the Oxygen Evolution Reaction to occur at a very low overpotential of 180 mV at just 20 mA cm−2. The CeF 3 -NiFeLDH catalyst manages to reach a current density of 1000 mA cm−2, at an overpotential of 340 mV. [Display omitted] The efficacy of any electrochemical reaction hinges on the extent of interaction achievable between reactive intermediates and the electrocatalytic active site. Any weak adsorption of these intermediates on the metal's active site results in low oxygen evolution reaction (OER) rates, mainly when catalysed by the Ni-based layered double hydroxide. To tackle this challenge, a heterojunction consisting of nickel-iron layered double hydroxide (NiFe-LDH) and cerium trifluoride (CeF 3) is synthesized. Both phases were developed in-situ to have an abundance of heterointerfaces. The charge transfer amid the NiFe-LDH and CeF 3 phases is brought about via these heterointerfaces. As a result, the overall charge dynamics associated with nickel (Ni) and iron (Fe) atoms are somewhat increased, and an enhanced positive charge on the metal site makes it more active in grabbing the reactive species, thereby making the entire OER process faster. The CeF 3 -NiFeLDH catalyst reaches a current density of 1000 mA cm−2 at an overpotential of 340 mV. Such a high current density is highly significant for the industrial-scale production of the products. The catalyst demonstrated impressive durability, maintaining stable performance for 90 h while operating at 500 mA cm−2. The charge dynamics between both phases were thoroughly examined using X-ray photoelectron spectroscopy (XPS). [ABSTRACT FROM AUTHOR]

Anion exchange membrane water electrolyzer (AEMWE) is a potentially cost‐effective technology for green hydrogen production. Although the normal current densities of AEMWEs are below 3 A ⋅ cm−2, operating them at higher current densities represents an efficient, but little‐explored approach to decrease the total cost of hydrogen production. We show here that a benchmark AEMWE has an operational lifetime of only seconds at an ultrahigh current density of 10 A ⋅ cm−2. By using a more conductive and robust AEM, and judicious choices of ionomers, catalyst, and porous transport layer, we have developed AEMWEs that stably operate at 10 A ⋅ cm−2 with extended lifetimes. The optimized AEMWE has an operational lifetime of more than 800 hours, a 5‐order magnetite improvement over the current benchmark. The cell voltage is only 2.3 V at 10 A ⋅ cm−2, comparable to those of the state‐of‐the‐art devices operating at current densities lower than 3 A ⋅ cm−2. This work demonstrates the potential of ultrahigh current density AEMWEs. [ABSTRACT FROM AUTHOR]

Glow discharges are known to be limited for running at high current densities (typically below 0.1 A ⋅ c m − 2 ). Magnetically enhanced plasmas overcome this limitation, reaching up to two orders of magnitude higher current densities. However, the highest reported discharge current density hardly reaches 10 A ⋅ c m − 2 even in high power impulse magnetron sputtering (HiPIMS). Here, we report on the long (∼1 ms) pulsed operation of the magnetron in helium with an over-dense current (∼30 A ⋅ c m − 2 , usual for arcs) while preserving the glow mode. This regime defying the arcs was called hyper power impulse magnetron (HyPIM) because the power injected per pulse is several times higher than in HiPIMS for the same average power and pulse duration. HyPIM operation mode is distinguished from HiPIMS by the limited pulse voltage and is unsuitable for thin film deposition but may interest plasma switches. These huge currents were obtained for two cathode materials, molybdenum (Mo) and tungsten (W). Different experimental diagnostics bring insights into the physical phenomena governing the HyPIM plasma. A discussion on the role played by the metal atoms on the current unveils the origin of such exceptional glow current all along the pulse and the key role of the helium metastable atoms. A schematic of the kinetic steps of the HyPIM discharge is proposed. [ABSTRACT FROM AUTHOR]

Electrolyte cations have been demonstrated to effectively enhance the rate and selectivity of the electrochemical CO2 reduction reaction (CO2RR), yet their implementation in electrolyte‐free membrane electrode assembly (MEA) electrolyzer presents significant challenges. Herein, an anchored cation strategy that immobilizes Cs+ on carbon vacancies was designed and innovatively implemented in MEA electrolyzer, enabling highly efficient CO2 electroreduction over commercial silver catalyst. Our approach achieves a CO partial current density of approximately 500 mA cm−2 in the MEA electrolyzer, three‐fold enhancement compared to pure Ag. In situ Raman and theoretical analyses, combined with machine learning potentials, reveal anchored Cs induces an electric field that significantly promotes the adsorption of *CO2− intermediates through performing muti‐point energy calculations on each structure. Furthermore, reduced adsorption of *OH intermediates effectively hampers competing hydrogen evolution reaction, as clarified by disk electrode experiments and density functional theory studies. Additionally, coupling our system with commercial polysilicon solar cells yields a notable solar‐to‐CO energy conversion efficiency of 8.3 %. This study opens a new avenue for developing effective cation‐promoting strategy in MEA reactors for efficient CO2RR. [ABSTRACT FROM AUTHOR]

Organic polymers are considered promising candidates for next‐generation green electrode materials in lithium‐ion batteries (LIBs). However, achieving long cycling stability and capacity retention at high current densities remains a significant challenge due to weak structural stability and low conductivity. In this study, we report the synthesis of two novel polyimide covalent organic frameworks (PI‐COFs), COF‐JLU85 and COF‐JLU86, by combining truxenone‐based triamine and linear acid anhydride through polymerization. These PI‐COFs feature layers with pore channels embedded with 18 carbonyl groups, facilitating rapid lithium‐ion diffusion and enhancing structural stability under high current densities. Compared to previously reported organic polymer materials, COF‐JLU86 demonstrates the excellent performance at high current densities, with an impressive specific capacity of 1161.1 mA h g−1 at 0.1 A g−1, and outstanding cycling stability, retaining 1289.8 mA h g−1 at 2 A g−1 after 1500 cycles and 401.1 mA h g−1 at 15 A g−1 after 10000 cycles. Additionally, in situ infrared spectroscopy and density functional theory (DFT) calculations provide mechanistic insights, revealing that the high concentration of carbonyl redox‐active sites and the optimized electronic structure contribute to the excellent electrochemical performance. These results highlight the potential of PI‐COFs as high‐performance organic electrode materials for LIBs, offering a promising solution to the challenges of long‐term stability and capacity retention at high current densities. [ABSTRACT FROM AUTHOR]

The development of advanced electrocatalysts with exceptional performance at high current densities is pivotal for reducing electric energy consumption in industrial water splitting for hydrogen production. Herein, a flexible one‐step electrodeposition approach is developed to synthesize superhydrophilic 3D flower‐like clusters of Cu–Co–P nanosheets grown in situ on nickel foam (NF). Introducing Cu into Co–P causes strong electron interactions, forming an electronic configuration favorable for the adsorption and desorption of intermediates, which significantly improves the intrinsic catalytic activity. The as‐deposited Cu–Co–P/NF display notable bifunctional catalytic activity with low overpotentials of 259 and 65 mV for the oxygen and hydrogen evolution reactions, respectively, at 10 mA cm−2. Superwetting 3D flower‐like nanostructures are conducive to the penetration of electrolytes and the rapid release of bubbles, enabling the efficient utilization of active sites and the timely release of bubble stress under high current densities. An assembled Cu–Co–P/NF(+, −) electrolyzer achieves an impressive voltage of 1.85 V at 500 mA cm−2 for water splitting and appreciable stability for over 220 h under simulated industrial conditions. This work offers an attractive strategy for regulating superaerophobic Co–P electrocatalysts for industrial water splitting, which can contribute to practical applications. [ABSTRACT FROM AUTHOR]

The adhesion of H2 bubbles on the electrode surface is one of the main factors limiting the performance of H2 evolution of electrolytic water, especially at high current density. To overcome this problem, here a “quasi‐gas phase” electrolytic water reaction system based on capillary effect is proposed for the first time to improve the mass transfer efficiency of H2. The typical feature of this reaction system is that the main site of H2 evolution reaction is transferred from the bulk aqueous solution to the gas phase environment above the bulk aqueous solution, thus effectively inhibiting the aggregation of H2 bubbles and reducing the resistance of their diffusion away. Electrochemical test results show that the proposed quasi‐gas phase system can significantly reduce the potential required in H2 evolution reaction process at high current density compared with the conventional electrolytic reaction system. Specifically, the overpotential potential is reduced by 0.31 V when the H2 evolution current density of 250 mA cm−2 is achieved. [ABSTRACT FROM AUTHOR]

Non‐iridium acid‐stabilized electrocatalysts for oxygen evolution reaction (OER) are crucial to reducing the cost of proton exchange membrane water electrolyzers (PEMWEs). Here, we report a strategy to modulate the stability of RuO2 by doping boron (B) atoms, leading to the preparation of a RuO2 catalyst with long‐range disorder (LD‐B/RuO2). The structure of long‐range disorder endowed LD‐B/RuO2 with a low overpotential of 175 mV and an ultra‐long stability, which can maintain OER for about 1.6 months at 10 mA cm−2 current density in 0.5 M H2SO4 with almost invariable performance. More importantly, a PEM electrolyzer using LD‐B/RuO2 as the anode demonstrated excellent performance, reaching 1000 mA cm−2 at 1.63 V with durability exceeding 300 h at 250 mA cm−2 current density. The introduction of B atoms induced the formation of a long‐range disordered structure and symmetry‐breaking B−Ru−O motifs, which enabled the catalyst structure to a certain toughness while simultaneously inducing the redistribution of electrons on the active center Ru, which jointly promoted and guaranteed the activity and long‐term stability of LD‐B/RuO2. This study provides a strategy to prepare long‐range disordered RuO2 acidic OER catalysts with high stability using B‐doping to perturb crystallinity, which opens potential possibilities for non‐iridium‐based PEMWE applications. [ABSTRACT FROM AUTHOR]

Manipulating the atomic structure of the catalyst and tailoring the dissociative water‐hydrogen bonding network at the catalyst‐electrolyte interface is essential for propelling alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), but remains a great challenge. Herein, we constructed an advanced a‐RuMo/NiMoO4/NF heterogeneous electrocatalyst with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO4 skeletons on Ni foam by a heteroatom implantation strategy. Theoretical calculations and in situ Raman tests show that the amorphous and alloying structure of a‐RuMo/NiMoO4/NF not only induces the directional evolution of interfacial H2O, but also lowers the d‐band center (from −0.43 to −2.22 eV) of a‐RuMo/NiMoO4/NF, the Gibbs free energy of hydrogen adsorption (ΔGH*, from −1.29 to −0.06 eV), and the energy barrier of HzOR (ΔGN2(g)=1.50 eV to ΔGN2*=0.47 eV). Profiting from these favorable factors, the a‐RuMo/NiMoO4/NF exhibits excellent electrocatalytic performances, especially at large current densities, with an overpotential of 13 and 129 mV to reach 10 and 1000 mA cm−2 for HER. While for HzOR, it needs only −91 and 276 mV to deliver 10 and 500 mA cm−2, respectively. Further, the constructed a‐RuMo/NiMoO4/NF||a‐RuMo/NiMoO4/NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm−2. [ABSTRACT FROM AUTHOR]

Anode‐free lithium metal batteries have attracted much attention due to their high energy density and lack of excess Li. In this work, Li film is deposited on large‐area copper foil (64 cm2) with good uniformity by a self‐designed electroplating device that quickly assembles and can be operated outside the glove box. By adding the high concentration of LiNO3 into the lithium bis(trifluoromethylsulfonyl)azanide (LiTFSI)‐based electrolyte, the high Li+ conductive solid electrolyte interface (SEI) layer regulated the Li+ flux, forming the columnar structure at a high current density of 40 mA cm−2, and compact morphology at 60 mA cm−2. Even at 100 mA cm−2, Li film on copper foil (Li@Cu) maintains its macroscopic uniformity. Furthermore, electrolytes, additives, and temperature are further optimized. The symmetric Li@Cu || Li cell cycle life can extend to 80 cycles. This work provides essential information for future manufacturing processes and scale‐up. [ABSTRACT FROM AUTHOR]

A one-dimensional computational model has been developed that can be used to identify operating conditions for the cathode side of a proton exchange membrane fuel cell such that both the inlet and outlet relative humidity is equal to 100%. By balancing the calculated pressure drop along the cathode side flow channel with the change in molar composition, inlet conditions for the cathode side can be identified with the goal of avoiding channel flooding. The channel length, height, width and the land-to-channel width ratio are input parameters for the model so that it might be used to dimension the cathode flow field. The model can be used to calculate the limiting current density, and we are presenting unprecedented high values as a result of the high pressure drop along the flow channels. Such high current densities can ultimately result in a fuel cell power density beyond the typical value of 1.0–2.0 W/cm2 for automotive fuel cells. [ABSTRACT FROM AUTHOR]

A one-dimensional computational model has been developed that can be used to identify operating conditions for the cathode side of a proton exchange membrane fuel cell such that both the inlet and outlet relative humidity is equal to 100%. By balancing the calculated pressure drop along the cathode side flow channel with the change in molar composition, inlet conditions for the cathode side can be identified with the goal of avoiding channel flooding. The channel length, height, width and the land-to-channel width ratio are input parameters for the model so that it might be used to dimension the cathode flow field. The model can be used to calculate the limiting current density, and we are presenting unprecedented high values as a result of the high pressure drop along the flow channels. Such high current densities can ultimately result in a fuel cell power density beyond the typical value of 1.0–2.0 W/cm2 for automotive fuel cells.

The partially amorphous NiFe LDH porous nanoarrays not only exhibits excellent electrocatalytic activity with an overpotential of 289 mV but also represents an outstanding stability over 80h at an ultra-high current density of 1 A cm−2, which contributes to the OER mechanism from traditional AEM to LOM. [Display omitted] • The partially amorphous NiFe-2.0 LDH displays an ultralow overpotential (η 10 = 189 mV). • NiFe-2.0 LDH exhibits a low overpotential of 289 mV and a long-term stability of 80 h at a current density of 1 A cm−2. • The introduction of Fe changes the OER mechanism from traditional AEM to LOM. Layered double hydroxide (LDH) serves as an innovative catalyst for water electrolysis, showcasing outstanding performance in the oxygen evolution reaction (OER) under alkaline conditions. However, it faces challenges due to its low electrical conductivity and limited accessibility to active sites. In this work, the flexibility advantages of disordered amorphous and ordered crystals in NiFe LDH were combined to improve OER performance and maintain long-term stability. This combination induces a variety of effects, including improving the intrinsic activity, changing the OER mechanism from adsorb evolution mechanism (AEM) to lattice oxygen mechanism (LOM), and promoting the reaction kinetics of the catalyst. Moreover, the porous structure of NiFe LDH can efficiently alleviate the issue of local acidic environment induced by prolonged OER reaction, satisfying the criteria for long-term stability. Therefore, the NiFe-2.0 LDH catalyst only requires an ultralow overpotential of 189 mV at a current density of 10 mA cm−2 with Tafel slope of 43 mV dec−1. More importantly, the catalyst not only displays excellent electrocatalytic activity with an overpotential of 289 mV but also represents an outstanding stability over 80 h at an ultra-high current density of 1 A cm−2. This study provides a promising strategy for optimizing the catalytic activity and stability of catalyst at ampere current density, which is expected to achieve commercial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A combined theory–experiment rational design strategy is employed. • Multi-method calculations revealed transformation of molybdates during OER. • A hollow sandwich-like FeOOH/(NiCo)MoO 4 heterostructure was fabricated. • FeOOH/(Ni 1 Co 1)MoO 4 shows super alkaline OER, ƞ 10 = 225 mV, ƞ 200 = 318 mV, ƞ 1000 = 546 mV. • FeOOH/(Ni 1 Co 1)MoO 4 shows a specific capacity of 342 mA h g−1 at 1 A g−1. Structural engineering, including electronic and geometric modulations, is a good approach to improve the activity of electrocatalysts. Herein, we employed FeOOH and the second metal center Ni to modulate the electronic structure of CoMoO 4 and used a low temperature solvothermal route and a chemical etching method to prepare the special hollow hierarchical structure. Based on the prediction of multi-method calculations by density functional theory (DFT) and ab initial molecular dynamics (AIMD), a series of materials were fabricated. Among them, the optimal hollow FeOOH/(Ni 1 Co 1)MoO 4 by coating (NiCo)MoO 4 nanosheets on FeOOH nanotubes showed excellent performances toward high current density oxygen evolution reaction (OER) in alkaline and simulated seawater solutions, hybrid supercapacitor (HSC), and aqueous battery due to the well-controlled electronic and geometric structures. The optimal FeOOH/(Ni 1 Co 1)MoO 4 required overpotentials of 225 and 546 mV to deliver 10 and 1000 mA cm−2 current densities toward alkaline OER, and maintained a good stability for 100 h at 200 mA cm−2 with negligible attenuation. The FeOOH/(Ni 1 Co 1)MoO 4 //Pt/C electrolyzer exhibited a low cell voltage of 1.52 and 1.79 V to drive 10 and 200 mA cm−2 and retained a long-term durability nearly 100 h at 1.79 V. As the electrode of energy storage devices, it possessed a specific capacity of 342 mA h g−1 at 1 A g−1. HSC and SC-type battery devices were fabricated. The assembled HSC kept a capacitance retention of 94 % after 10,000 cycles. This work provided a way to fabricate effective and stable multifunctional materials for energy storage and conversion with the aid of multi-method calculations. [ABSTRACT FROM AUTHOR]

Addition of organic compounds containing O/N heteroatoms to aqueous electrolytes such as ZnSO4 (ZS) solutions is one of the effective strategies to inhibit Zn anode dendrites and side reactions. However, addressing the stability of Zn plating/stripping at high current densities and areal capacities by this method is still a challenge, especially in capacitors known for high power and long life. Herein, an organic heterocyclic compound of 1, 4, 7, 10‐tetraazacyclododecane (TC) containing four symmetrically distributed N atoms is employed as ZS additive, expanding the life of Zn anodes from ≈ 30 h to 1000 and 240 h at deep plating/stripping conditions of 10 and 20 mA cm−2/mAh cm−2, respectively; the cumulative capacity is as high as 5.0 Ah cm−2 with 99% Coulombic efficiency, far exceeding reported additives. TC with higher binding energies than H2O for Zn species tends to adsorb to Zn (002) in a lying manner and participate in the solvation shell of Zn2+, thus avoiding Zn dendrites and side‐reaction damage, especially at high current densities. The TC‐endowed Zn anode's stability under such extreme conditions is verified in Zn‐ion capacitors (i.e., > 94.6% capacity retention after 28 000 cycles), providing new insights into the development of high‐power Zn‐based energy storage devices. [ABSTRACT FROM AUTHOR]

This paper focuses on proton exchange membrane fuel cell (PEMFC) operation at current densities in the order of 6 A/cm2. Such high current densities are conceivable when the traditional carbon fiber papers are replaced with perforated metal plates as the gas diffusion layer to enhance waste heat removal, and at the same time the relative humidity inside the fuel cell is kept below 100% by applying appropriate operating conditions as was found in previous one-dimensional modeling work. In the current paper, we applied a three-dimensional, multi-phase computational fluid dynamics model based on Ansys-CFX to obtain additional insight into the underlying physics. The calculated pressure drops are in very good agreement with previous one-dimensional modeling work, and the current densities in all case studies are in the order of 5–6 A/cm2, but different from the previous one-dimensional study, the results suggest that the relative humidity is very close to 100% throughout the entire channel length when the inlet relative humidity is 100%, ensuring best hydration cell conditions and hence best performance. Importantly, the model results suggest that fuel cell performance at a high current density in conjunction with relatively low stoichiometric flow ratios around 1.5–2 is possible. [ABSTRACT FROM AUTHOR]

The production and use green hydrogen fuel is attracted significantly in recent years owing to its high energy density and zero carbon emission. In this paper, Fe2V4O13 nanoparticles of size 22 nm are coated on the nickel foam substrate and this modified electrode is used as electrode towards the electrocatalysis of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte. The Fe2V4O13 nanoparticles exhibit high electrochemical active surface area of 2652 cm− 2 which is about ~ 2 and ~ 100 times higher than that of RuO2 (1302 cm− 2) and bare nickel foam (22.5 cm− 2). The observed high electrochemical active surface area for Fe2V4O13 nanoparticles results in enhanced OER and HER performance where it requires an overpotentials of 310 mV in OER and − 181 mV in HER to deliver the high current density of 100 mA cm− 2. The electrochemical activity of the proposed Fe2V4O13 nanoparticles evidenced as a competitive electrocatalyst for both OER and HER. [ABSTRACT FROM AUTHOR]

Polymetallic layered double hydroxides are promising cost-effective catalysts for the oxygen evolution reaction (OER) due to their versatile anionic and cationic tunability. Nevertheless, several challenges persist, notably, issues related to low electrical conductivity, poor catalytic activity, and stability, especially at high current density. Herein, we report the design of Ce- and La-doped CoNiFe-layered double hydroxide (CeLaCoNiFe-LDH) nanosheets through a facile and scalable in situ self-assembly strategy that displays enhanced OER activity. Experimental and theoretical investigations provide insights into the impact of Ce-and La-doping by comparing CeCoNiFe-LDH, LaCoNiFe-LDH, and pristine CoNiFe-LDH, all synthesized using the same methodology. These results reveal that doping Ce3+ and La3+ into CoNiFe-LDH substantially improves its electronic structure, resulting in enhanced conductivity, more oxygen vacancies (Vo), electron interaction, and active site formation. Consequently, significantly reduced overpotentials of 175, 314, and 424 mV at 10, 100, and 500 mA cm−2, respectively, and a highly stable current density of 120 h in 1 M KOH were achieved. Notably, these performance metrics surpass those of unmodified LDHs and are competitive with many lanthanide-doped transition metal-based LDH electrocatalysts, as well as noble metal catalysts like ruthenium catalysts. This work represents a pioneering effort in doping Ce3+ and La3+ ions into a functional CoNiFe-based electrocatalyst, offering inspiring OER performance and scalability potential. [ABSTRACT FROM AUTHOR]

Hydrogen is now recognized as the primary alternative to fossil fuels due to its renewable, safe, high-energy density and environmentally friendly properties. Efficient hydrogen production through water splitting has laid the foundation for sustainable energy technologies. However, when hydrogen production is scaled up to industrial levels, operating at high current densities introduces unique challenges. It is necessary to design advanced electrocatalysts for hydrogen evolution reactions (HERs) under high current densities. This review will briefly introduce the challenges posed by high current densities on electrocatalysts, including catalytic activity, mass diffusion, and catalyst stability. In an attempt to address these issues, various electrocatalyst design strategies are summarized in detail. In the end, our insights into future challenges for efficient large-scale industrial hydrogen production from water splitting are presented. This review is expected to guide the rational design of efficient high-current density water electrolysis electrocatalysts and promote the research progress of sustainable energy. [ABSTRACT FROM AUTHOR]

The rapid growth of lithium (Li) dendrites has long hindered the development of all‐solid‐state lithium‐metal batteries (ASSLMB). Here, a composite soft carbon (SC)‐nano Si3N4 (SiN) interlayer (SC‐SiN) is designed for in situ formation of Li3N network (with high ionic conductivity/diffusivity) after lithium embedding in nano‐Si3N4, promoting the rapid migration of Li+ and guiding the metal Li to be deposited uniformly in a 3D manner within the interlayer. It can solve the problem of rapid consumption of Li+ and local charge accumulation at the interface of solid electrolyte and Li metal anode, thus avoiding the growth of Li‐dendrites. The resulting LCO/LPSCl/SC‐SiN‐Li ASSLMB achieves ultra‐high current density (12.5 mA cm−2) and ultra‐long cycle life (22 000 cycles with no degradation), as well as ultra‐high area capacity area capacity (15 mAh cm−2) and energy density (402.5 Wh kg−1), all of which break existing ASSLMB records. In addition, it is capable of 600 cycles at an areal capacity of 2.7 mAh cm−2 and 2 C (85.7% capacity retention). A pouch cell is also assembled to delivers high energy density (>320 Wh kg−1). These confirm the application potential of this configuration and are one of the most critical breakthroughs toward the commercialization of the ASSLMB. [ABSTRACT FROM AUTHOR]

We found that a mixture of rhombohedral boron monosulfide (r-BS) and graphene nanoplates (GNP) exhibits higher OER activity than commercially available ruthenium oxide. Furthermore, it was shown that when a mixture of r-BS and GNP was further supported on nickel foam, it did not deteriorate even after continuous operation at high output for more than 100 hours. Here, we will introduce these results in detail. [ABSTRACT FROM AUTHOR]

Nickel mesh (NM) is used in industrial alkaline water electrolyzers due to its cost‐effectiveness and conductivity. However, the decisive factors that advance the efficiency and sustainability of such electrodes are only partially understood. Herein, an efficient NM‐based electrocatalyst for the oxygen evolution reaction is developed via a single‐step nitridation route on a commercially used NM substrate and sheds light on the role of reconstruction and iron content to boost catalyst performance and durability. Remarkably, the activated Ni3N/NM catalyst required an overpotential of 0.46 V to deliver 1 A cm−2 in ambient conditions (1 M KOH, 25 °C). This overpotential decreases substantially to 0.28 V in industrially relevant conditions (6 M KOH, 85 °C) and is maintained for 235 h. Ni3N/NM partially transformed into NiFe layered (oxy)hydroxide in both conditions, while the active structure's Fe content is reconstruction condition dependent (temperature and KOH concentration). Electrodes reconstructed under industrially relevant conditions performed better than ambient reconstructed ones due to a more pronounced iron‐incorporation from KOH and the evolution of porous morphologies. In industrial environments, activated Ni3N/NM excels in selectively converting benzyl alcohol to benzoic acid, achieving an impressive yield of 96%. [ABSTRACT FROM AUTHOR]

The chlorine evolution reaction (CER) is a crucial step in the production of chlorine gas and active chlorine by chlor-alkali electrolysis. Currently, the endeavor to fabricate electrodes capable of yielding high current density at minimal overpotential remains a central challenge in advancing the realm of chlorine evolution reactions. Here, we grow TiO2 and RuO2 on MXene@carbon cloth (CC) through the favorable affinity and induced deposition effect between the surface functional groups of MXene and the metal. A self-supported electrode (RuTiO2/MXene@CC) with strong binding at the electrocatalyst–support interface and weak adhesion at electrocatalyst–bubble interface is constructed. The RuTiO2/MXene@CC can reduce the electron density of RuO2 by regulating the electron redistribution at the heterogeneous interface, thus enhancing the adsorption of Cl−. RuTiO2/MXene@CC could achieve a high current density of 1000 mA·cm−2 at a small overpotential of 220 mV, superior to commercial dimensionally stable anodes (DSA). This study provides a new strategy for constructing efficient CER catalysts at high current density. [ABSTRACT FROM AUTHOR]

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Achieving a high current density during electrochemical overall water splitting is a promising strategy for industrial energy conversion. The mass diffusion rate of OH− ions from the electrolyte to the interfacial active sites strongly influences the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, the delayed‐release of OH− ions modulated by a proper organic polymer membrane on the electrode surface can optimize the OH− accessibility to the active sites (as indicated by the molecular dynamics simulations) is demonstrated and that van der Waals interaction force modulates the OH− residence time in the reaction system. The remarkable performance of the membrane‐modified electrode is achieved at ultra‐high current densities of 1.9 A cm−2 (with an HER overpotential of 602 mV) and 2 A cm−2 (with an OER overpotential of 459 mV) in 1 M KOH solution. Consequently, a super‐high current density of 1.3 A cm−2 is obtained for overall water splitting (at a voltage of only 2.2 V), which is 1.9‐fold higher than that of a benchmarked Pt/C‐IrO2 (684 mA cm−2). Therefore, the delayed‐release of OH− has optimized the mass conversion efficiency of the active sites, thus improving the electrochemical performance of overall water splitting. [ABSTRACT FROM AUTHOR]

Electrocatalysts play a crucial role in hydrogen production via water splitting, yet their effectiveness is hampered by the bubble effect, particularly under high‐current‐density conditions. Herein, nickel foam with mountain‐shaped nanostripes (NFMN) is developed as a universal substrate for electrocatalysts to remove gas bubbles efficiently, ensuring high‐performance high‐current‐density water splitting. The NFMN is fabricated through facet engineering of nickel foam (NF) via thiocyanate‐guided acid etching. Specifically, when immersed into an acidic thiocyanate solution, the (220) plane of NF is preferentially adsorbed by SCN−, protecting it, while the (111) and (200) facets remain exposed and are selectively etched by the acid. As the etching proceeds parallelly to the (220) direction, mountain‐shaped nanostripes are obtained. The nanostripes confer the benefits of superaerophobicity and local circulation, allowing the NFMN to efficiently release gas bubbles. As a proof‐of‐concept application, the NFMN is employed as a novel substrate to support the FeOOH anode and Ni2P cathode for a prototype electrolyzer, which exhibits a low cell voltage of 1.847 V at a large current density of 500 mA cm−2 with high stability. This work opens up new opportunities to construct efficient substrates for high‐current‐density water splitting and beyond. [ABSTRACT FROM AUTHOR]

The exploration of highly efficient noble metal-free catalysts for overall water splitting in alkaline water/seawater at large-current density is critical for industrial application. In this work, FeCo-MOF derived hierarchical Co 4 S 3 /Fe 3 S 4 /MoS 2 nanosheet arrays on iron foam (IF) were prepared as efficient electrocatalyst for both HER and OER by solvothermal method. The CFM 0.3 nanosheet arrays exhibited the high HER performance with the Tafel slope of 70 mV dec-1 and extremely low overpotential of 241, 377 mV at 100 and 500 mA/cm2. The CFM 0.7 nanosheet arrays can deliver a high current density of 100 and 500 mA/cm2 at the overpotential as low as 220 and 305 mV and small Tafel slope (79 mV dec-1) for OER. Moreover, CFM0.3/CFM0.7 exhibited the low overpotentials of 270/380 mV for HER/OER at 100 mA/cm2 in simulated seawater. The CFM0.3//CFM0.7 delivered comparatively low cell voltage of 1.26/1.45 V at 10 mA/cm2 with excellent stability for 48 h in alkaline water/simulated seawater. Benefiting from the three-dimensional nanosheet arrays framework and the interface coupling interactions of trimetallic sulfides, the self-supporting robustness electrodes with abundant multimetallic electroactive centers can regulate charge/ion diffusion path and electronic structure for prompting HER and OER activity at high current density. Hence, this work would provide new ideas for exploration of highly-active MOF-derived non-noble metal bifunctional catalysts for energy-related applications. The Co 4 S 3 /Fe 3 S 4 /MoS 2 (CFM) nanosheet arrays on IF were prepared as an efficient electrocatalyst for both HER and OER. CFM 0.3 exhibited low overpotential of 241, 377 mV at 100 and 500 mA/cm2 for HER. CFM 0.7 showed low overpotential of 220 and 305 mV at 100 and 500 mA/cm2 for OER. CFM 0.3 and CFM 0.7 exhibited the low HER and OER overpotentials of 270 and 380 mV at 100 mA cm−2 in simulated seawater. CFM 0.3//CFM 0.7 delivered comparatively low cell voltages of 1.26 and 1.45 V at 10 mA/cm2 for overall water/seawater splitting. [Display omitted] • Co 4 S 3 /Fe 3 S 4 /MoS 2 nanosheet arrays were fabricated on IF by solvothermal method. • CFM0.3 exhibited 241(270)/377 mV at 100/500 mA/cm2 in 1.0 M KOH(seawater) for HER. • CFM0.7 exhibited 220(380)/305 mV at 100/500 mA/cm2 in 1.0 M KOH(seawater) for OER. • CFM0.3//CFM0.7 exhibited 1.26(1.45V) at 10 mA/cm2 for 48 h in 1.0 M KOH(seawater). [ABSTRACT FROM AUTHOR]

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[Display omitted] Lithium-oxygen batteries (LOBs) with a theoretical energy density of up to 3500 Wh kg−1 hold a promise for the next-generation high-energy-density batteries. However, the slow oxygen reduction/evolution kinetics at the cathode limits the performance of Li-air batteries. The rational design of efficient catalysts is essential for the improvement of oxygen electrode reaction kinetics. Herein, we report a facile strategy to co-dope N and P atoms simultaneously into Ti 3 C 2 T x (NP-Ti 3 C 2 T x) MXene via an electrostatic self-assembly approach. The co-doped NP-Ti 3 C 2 T x layers expose abundant active sites, providing more space for accommodating the formed Li 2 O 2. Moreover, the N and P co-doping facilitates efficient electron transport in Ti 3 C 2 T x MXene. The LOB with NP-Ti 3 C 2 T X catalyst delivers a high discharge capacity of 24,940 mAh/g at 1000 mA g−1. At a cut-off capacity of 1000 mAh/g, this battery runs continuously for 159, 276, 185, and 229 cycles at current densities of 1000, 2000, 3000, and 5000 mA g−1, respectively. Theoretical calculations unveil that N and P co-doping enables lower ηORR and ηOER of only 0.26 V and 0.13 V on Ti 3 C 2 T x MXene, respectively. This work offers a feasible approach for constructing efficient MXene electrocatalysts for Li–air batteries. [ABSTRACT FROM AUTHOR]

Abstract Addition of organic compounds containing O/N heteroatoms to aqueous electrolytes such as ZnSO4 (ZS) solutions is one of the effective strategies to inhibit Zn anode dendrites and side reactions. However, addressing the stability of Zn plating/stripping at high current densities and areal capacities by this method is still a challenge, especially in capacitors known for high power and long life. Herein, an organic heterocyclic compound of 1, 4, 7, 10‐tetraazacyclododecane (TC) containing four symmetrically distributed N atoms is employed as ZS additive, expanding the life of Zn anodes from ≈ 30 h to 1000 and 240 h at deep plating/stripping conditions of 10 and 20 mA cm−2/mAh cm−2, respectively; the cumulative capacity is as high as 5.0 Ah cm−2 with 99% Coulombic efficiency, far exceeding reported additives. TC with higher binding energies than H2O for Zn species tends to adsorb to Zn (002) in a lying manner and participate in the solvation shell of Zn2+, thus avoiding Zn dendrites and side‐reaction damage, especially at high current densities. The TC‐endowed Zn anode's stability under such extreme conditions is verified in Zn‐ion capacitors (i.e., > 94.6% capacity retention after 28 000 cycles), providing new insights into the development of high‐power Zn‐based energy storage devices.

Arsenic is the only beneficial impurity for copper electrorefining through inhibiting anode passivation and the formation of floating slimes. The behaviour of copper anodes with different content of arsenic were studied at high current density (>280 A/m 2). It showed that low arsenic anodes (As < 300 ppm) easily generated anode passivation, floating slimes and cathode nodules during the electrorefining proccess. The floating slimes, electrolyte, cathode and anode were observed and analyzed. As result, low arsenic anodes were more likely to be passivated due to their microstructure defects and irregular microstructure. Increasing electrolyte temperature and addition of glycerol were propitious to reduce low arsenic anodes’ passivation. The floating slimes occured when the concentration of As(III) in electrolyte decreased to 1 g/L, and they would be precipitated by polyacrylamide. All measures greatly improved the cathode quality at current density of 300 A/m 2.

Hydrogen generation by water electrolysis using solid oxide electrolysis cells (SOECs) is highly promising because of the favorable thermodynamics and kinetics. Commercial applications require SOEC operating at high current densities (ǀiǀ≥1 A·cm−2) to achieve substantial hydrogen production rates. This study demonstrates the operation of a full-size Ni–yttria-stabilized zirconia (Ni–YSZ) cell with an effective area of 16 cm2 at −2 A·cm−2 for 336 h, illustrating the feasibility of operating SOECs at a high current density. The electrochemical characteristics of the SOEC evolved during constant current electrolysis, exhibiting an activation stage with a degradation rate (DR) of 54.6 mV/100 h, followed by a rapid decline process(DR: 180.9 mV/100 h), a gentle decline period (DR: 105.5 mV/100 h), and a stable stage (DR: 11.0 mV/100 h). The contributions of individual processes to cell degradation during each process are identified using the distribution of relaxation times (DRT) and subsequent equivalent circuit model (ECM) fitting. The results suggest that the Ohmic resistance, ionic transport and charge-transfer reaction in the Ni-YSZ fuel electrode contribute the most to performance loss. Ni redistribution is regarded as the dominant degradation mechanism, as verified by detailed post-test characterization. • The degradation of Solid oxide electrolysis cell operating at high current density was studied. • The relaxation time to stability under high current density is shorter. • The degradation stage is divided into more detailed 4 stages. • The degradation in the fuel electrode contribute most of the cell's performance loss. • Sr segregation are observed without generation of high resistance phases. [ABSTRACT FROM AUTHOR]

The electrosynthesis of hydrogen peroxide (H2O2) via two‐electron (2e−) oxygen (O2) reduction reaction (ORR) has great potential to replace the traditional energy‐intensive anthraquinone process, but the design of low‐cost and highly active and selective catalysts is greatly challenging for the long‐term H2O2 production under industrial relevant current density, especially under neutral electrolytes. To address this issue, this work constructed a carboxylated hexagonal boron nitride/graphene (h‐BN/G) heterojunction on the commercial activated carbon through the coupling of B, N co‐doping with surface oxygen groups functionalization. The champion catalyst exhibited a high 2e− ORR selectivity (>95 %), production rate (up to 13.4 mol g−1 h−1), and Faradaic efficiency (FE, >95 %). The long‐term H2O2 production under the high current density of 100 mA cm−2 caused the cumulative concentration as high as 2.1 wt %. The combination of in situ Raman spectra and theoretical calculation indicated that the carboxylated h‐BN/G configuration promotes the adsorption of O2 and the stabilization of the key intermediates, allowing a low energy barrier for the rate‐determining step of HOOH* release from the active site and thus improving the 2e− ORR performance. The fast dye degradation by using this electrochemical synthesized H2O2 further illustrated the promising practical application. [ABSTRACT FROM AUTHOR]

Developing non-precious metal-based electrocatalysts operating in high-current densities is highly demanded for the industry-level electrochemical hydrogen evolution reaction (HER). Here, we report the facile preparation of binder-free Mo2C-Mo2N heterostructures on carbon nanowalls/diamond (CNWs/D) via ultrasonic soaking followed by an annealing treatment. The experimental investigations and density functional theory calculations reveal the downshift of the d-band center caused by the heterojunction between Mo2C/Mo2N triggering highly active interfacial sites with a nearly zero ∆GH* value. Furthermore, the 3D-networked CNWs/D, as the current collector, features high electrical conductivity and large surface area, greatly boosting the electron transfer rate of HER occurring on the interfacial sites of Mo2C-Mo2N. Consequently, the self-supporting Mo2C-Mo2N@CNWs/D exhibits significantly low overpotentials of 137.8 and 194.4 mV at high current densities of 500 and 1000 mA/cm2, respectively, in an alkaline solution, which far surpass the benchmark Pt/C (228.5 and 359.3 mV) and are superior to most transition-metal-based materials. This work presents a cost-effective and high-efficiency non-precious metal-based electrocatalyst candidate for the electrochemical hydrogen production industry. [ABSTRACT FROM AUTHOR]

Hot electron transistors (HETs) represent an exciting new device for integration into semiconductor technology, holding the promise of high‐frequency electronics beyond the limits of SiGe bipolar hetero transistors. With the exploration of 2D materials such as graphene and new device architectures, hot electron transistors have the potential to revolutionize the landscape of modern electronics. This study highlights a novel hot electron transistor structure with a record output current density of 800 A cm−2 and a high current gain α, fabricated using a scalable fabrication approach. The hot electron transistor structure comprises 2D hexagonal boron nitride and graphene layers wet transferred to a germanium substrate. The combination of these materials results in exceptional performance, particularly in terms of the highly saturated output current density. The scalable fabrication scheme used to produce the hot electron transistor opens up opportunities for large‐scale manufacturing. This breakthrough in hot electron transistor technology holds promise for advanced electronic applications, offering high current capabilities in a practical and manufacturable device. [ABSTRACT FROM AUTHOR]

Sodium‐metal batteries (SMBs) are considered as a promising route to realize a high energy density battery, showing potential for applications in large‐scale energy storage. However, the cycling stability and reversibility of the Na‐metal anode suffer from significant challenges because of the growth of Na dendrites. This study reports an active/inactive Co‐Sn alloy interface to suppress the growth of Na dendrites under harsh test conditions. In this interface, Sn provides abundant nucleation sites and Co plays a synergistic role in alleviating volume variation of Sn nanoparticles and increasing the interaction between Na and substrate, significantly promoting the uniform Na deposition and preventing the Na plating from the root of the deposited Na. Under High‐current‐density (12 mA cm−2) with a high depth of discharge (DOD, 66.67%), Na||Na can achieve stable cycling for over 4200 h at 4 mA h cm−2. When paired with a high‐loading NaTi2(PO4)3 cathode (10 mg cm−2), SMB delivers an excellent performance (800 cycles) at a negative‐to‐positive electrode capacity (N/P) ratio up to 2. [ABSTRACT FROM AUTHOR]

Enhanced oxygen evolution reaction (OER) kinetics plays an important role in the large-scale production of hydrogen via water electrolysis. In this regard, the crystallinity of FeVO 4 is tuned from amorphous to semicrystalline and fully crystalline via precipitation followed by controlled thermal treatment. The prepared FeVO 4 samples show a uniform distribution of spherical nanoparticles (40–60 nm). The tailored amorphous, semicrystalline, and fully crystalline FeVO 4 samples are immobilized on nickel foam and their OER performance was studied. The OER performance of amorphous, semicrystalline, and fully crystalline FeVO 4 shows in the order of amorphous FeVO 4 > semicrystalline FeVO 4 > fully crystalline FeVO 4. The amorphous FeVO 4 demonstrates magnificent enhanced OER kinetics with a small overpotential and high current density compared to the semicrystalline and fully crystalline FeVO 4. The amorphous FeVO 4 exhibits an overpotential of 310 mV at a high current density of 1000 mA cm−2 and also exhibits exemplary stability over 95 h, while semicrystalline FeVO 4 and fully crystalline FeVO 4 respectively require 360 mV and 390 mV to drive a relatively lower current density of 500 mA cm−2. [ABSTRACT FROM AUTHOR]

The wide application of portable electrical equipment, aerial vehicles, smart robotics, etc. has boosted the development of advanced batteries with safety, high energy density, and environmental adaptability. Inspired by the fat layer on animal bodies, biomimetic fat is constructed as electrolytes of solid‐state zinc‐air batteries to achieve excellent cycling performance at low temperatures. Via tailored anion‐H2O interaction, the antifreezing gel electrolytes, with the multi‐performance of interface compatibility, temperature adaptability, and stable power supply simultaneously, build robust Zn|electrolyte interface, thus promoting uniform interfacial electric fields and Zn deposition. Excellent long‐term cyclability of 120 h at a high current density of 50 mA cm−2 are exhibited at 25 °C. Moreover, at −40 °C, a record‐long cycling life of 205 h at a current density as large as 10 mA cm−2 is achieved. [ABSTRACT FROM AUTHOR]

With rich corner sites and edge sites, the amorphous-crystalline NiCo(OH) 2 catalyst exhibits superior catalytic OER and HER activities at high current densities since the amorphization can promote the partial electron transfer from Co to Ni species and result in the tensile Ni-O bonds. The coordinatively unsaturated Ni sites in up-shift d -band centers toward Fermi level can reduce the antibonding states, creating optimized adsorption and promoting both OER and HER. [Display omitted] • Successfully synthesized 2D NiCo(OH) 2 catalyst with amorphous-crystalline structure. • Achieved high catalytic OER and HER activities at high current densities in the application of anion exchange membrane electrolysers for water-electrolysis. • Fundamentally investigated the structural characteristics and catalytic mechanism of amorphous catalysts.. The large overpotential required for oxygen evolution reaction (OER) is one of the major factors limiting the efficiency of electrochemical water-electrolysis for hydrogen production. In this work, to decrease OER energy barrier and obtain low overpotential, amorphous-crystalline NiCo(OH) 2 nanoplates are in-situ grown on nickel foam surface to form a catalyst-based electrode (ac-NiCo(OH) 2 /NF) for water-electrolysis application. As the inner amorphization of NiCo(OH) 2 results in increased electron density of the metal sites, leading to the formation of tensile Ni-O bond, the coordinatively unsaturated Ni sites in the down-shift d -band centers toward Fermi level can lower the antibonding states. This can lead to optimized adsorption and desorption energies for oxygen-containing intermediates for OER. As expected, the prepared ac-NiCo(OH) 2 /NF electrode presents a low overpotential of 364 mV to deliver 1000 mA cm−2 toward OER with impressively high robust stability. When this electrocatalyst electrode serves as both the anode and cathode, the assembled anion exchange membrane (AEM) electrolyser only needs a cell voltage of 1.68 V to drive the overall water-electrolysis process at a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

It remains challenging to design alkaline hydrogen evolution reaction (HER) electrocatalyst able to stably operate at ampere-level current density. In this work, we successfully synthesized heterostructured Ni 3 S 2 /Cr 2 S 3 nanosheets on nickel foam (Ni 3 S 2 /Cr 2 S 3 /NF) for high current HER electrocatalysis in alkaline media. As-prepared Ni 3 S 2 /Cr 2 S 3 /NF reaches 0.5 and 1.0 A cm−2 currents at 230 and 333 mV overpotential, respectively. After 50 h test at 0.5 A cm−2, the potential of Ni 3 S 2 /Cr 2 S 3 /NF remained almost unchanged. This impressive HER performance stems from its unique hybridization nature enabled hydrogen spillover, in which Cr 2 S 3 efficiently catalyzes the Volmer step, i.e., water dissociation to generate hydrogen, and the latter further transports to neighboring Ni 3 S 2 via spillover to facilitate the molecular hydrogen formation. This work provides a feasible strategy to synthesize efficient and durable HER catalysts for ampere-level water splitting. • Heterostructured bimetallic sulfide Ni 3 S 2 /Cr 2 S 3 was prepared by a one-step hydrothermal method. • The catalyst exhibits remarkable HER activity under alkaline conditions. • The hydrogen spillover provides an effective way to accelerate multi-step HER through relay catalysis. • The catalyst requires low overpotentials of 333 mV to reach 1000 mA cm−2 with long-term durability. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction (CO2R) coupled with renewable electricity has been considered as a promising route for the sustainability transition of energy and chemical industries. However, the unsatisfactory yield of desired products, particularly multicarbon (C2+) products, has hindered the implementation of this technology. This work describes a strategy to enhance the yield of C2+ product formation in CO2R by utilizing spatial confinement effects. The finite element simulation results suggest that increasing the number of shells in the catalyst wil lead to a high local concentration of *CO and promotes the formation of C2+ products. Inspired by this, Cu nanoparticles are synthesized with desired hollow multi‐shell structures. The CO2 reduction results confirm that as the number of shells increase, the hollow multi‐shell copper catalysts exhibit improved selectivity toward C2+ products. Specifically, the Cu catalyst with 4.4‐shell achieved a high selectivity of over 80% toward C2+ at a current density of 900 mA cm−2. Evidence from in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy unveils that the multi‐shell Cu catalyst exhibits an enhanced *COatop coverage and the stronger interaction with *COatop compared to commercial Cu, confirming the simulation results. Overall, the work promises an effective approach for boosting CO2R selectivity toward value‐added chemicals. [ABSTRACT FROM AUTHOR]

Exploring highly efficient oxygen evolution reaction (OER) electrocatalysts is important for industrial water electrolysis, especially under high current densities (>1 A cm−2). High‐entropy alloy (HEA) with high surface OER activity and excellent electrical conductivity of the core is an ideal route to improve the catalytic activity. Herein, a combined theoretical and experimental approach to establish core–shell FeCoNiMoAl‐based HEA as a promising OER electrocatalyst is presented. Theoretical calculations combined with structure analyses indicate crystalline–amorphous (c–a) heterostructure of shell reduces the electron transfer resistance and generates more active sites, furthermore the crystalline core improves the conductivity and self‐supporting ability. HEA electrodes demonstrate superior OER performance with an overpotential (η) of 470 mV at 2 A cm−2 and no apparent degradation even after 330 h of continuous testing, notably, for overall water splitting the stability is more than 120 h at 2.06 V. The special core–shell structure achieves a win–win strategy for high OER activity and stability. These findings shed light on the structural design of HEA electrocatalysts and present a promising route to achieve highly efficient electrocatalysts for industrial water electrolysis and relevant energy conversion processes. [ABSTRACT FROM AUTHOR]

Exploring highly efficient oxygen evolution reaction (OER) electrocatalysts is important for industrial water electrolysis, especially under high current densities (>1 A cm−2). High‐entropy alloy (HEA) with high surface OER activity and excellent electrical conductivity of the core is an ideal route to improve the catalytic activity. Herein, a combined theoretical and experimental approach to establish core–shell FeCoNiMoAl‐based HEA as a promising OER electrocatalyst is presented. Theoretical calculations combined with structure analyses indicate crystalline–amorphous (c–a) heterostructure of shell reduces the electron transfer resistance and generates more active sites, furthermore the crystalline core improves the conductivity and self‐supporting ability. HEA electrodes demonstrate superior OER performance with an overpotential (η) of 470 mV at 2 A cm−2 and no apparent degradation even after 330 h of continuous testing, notably, for overall water splitting the stability is more than 120 h at 2.06 V. The special core–shell structure achieves a win–win strategy for high OER activity and stability. These findings shed light on the structural design of HEA electrocatalysts and present a promising route to achieve highly efficient electrocatalysts for industrial water electrolysis and relevant energy conversion processes. [ABSTRACT FROM AUTHOR]