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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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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 RuO 2 by doping boron (B) atoms, leading to the preparation of a RuO 2 catalyst with long-range disorder (LD-B/RuO 2 ). The structure of long-range disorder endowed LD-B/RuO 2 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 H 2 SO 4 with almost invariable performance. More importantly, a PEM electrolyzer using LD-B/RuO 2 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/RuO 2 . This study provides a strategy to prepare long-range disordered RuO 2 acidic OER catalysts with high stability using B-doping to perturb crystallinity, which opens potential possibilities for non-iridium-based PEMWE applications., (© 2024 Wiley-VCH GmbH.)

Alkaline methanol-water electrolysis system is regarded as an appealing strategy for electro-reforming methanol into formate and producing hydrogen with low energy-consumption compared with alkaline water electrolysis. However, stability and selectivity under high current densities for practical application remain challenging. Herein, a CeF 3 @Ni 3 N nanosheets array anchored on carbon cloth (CeF 3 @Ni 3 N/CC) was fabricated. The gradual extrusion of F species from Ni(OH) 2 lattices can stabilize hierarchical structure and construct abundant heterostructure interfaces. Moreover, CeF 3 can modulate electron distribution of Ni 3 N, thus simultaneously enhancing the surface adsorption kinetics and capability of methanol and OH - , which is conducive to enhanced methanol oxidation reaction (MOR) activity and selectivity. Therefore, bifunctional CeF 3 @Ni 3 N/CC exhibits low potential of 1.43 V at 500 mA cm -2 , along with high stability over 72 h and high faradaic efficiency (FEs) in MOR, as well as an overpotential of 76 mV to achieve 50 mA cm -2 for hydrogen evolution reaction (HER). Furthermore, membrane-free CeF 3 @Ni 3 N/CC||CeF 3 @Ni 3 N/CC cell for MOR||HER delivers high electrocatalytic activity, long-term stability and FEs at high current density of 300 mA cm -2 . This study highlights the importance of optimizing surface adsorption behavior of active species, as well as rational design of highly efficient heterostructure electrocatalysts for methanol upgrading coupled with hydrogen production., (© 2024 Wiley-VCH GmbH.)

The rational design of multi-site electrocatalysts with three different functions for facile H 2 O dissociation, H-H coupling, and rapid H 2 release is desirable but difficult to achieve. This strategy can accelerate the sluggish kinetics of the hydrogen evolution reaction (HER) under alkaline conditions. To resolve this issue, a Mo/Ru-based catalyst with three different active sites (Ru/Mo 2 C/MoO 2 ) is rationally designed and its performance in alkaline HER is evaluated. The experimental results and density functional theory calculations revealed that, at the heterogeneous Mo 2 C/MoO 2 interface, the higher valence state of Mo (MoO 2 ) and the lower valence state of Mo (Mo 2 C) exhibited strong OH - and H - binding energies, respectively, which accelerated H 2 O dissociation. Moreover, the interfacial Ru possessed an appropriate hydrogen binding energy for H-H coupling and subsequent H 2 evolution. Thus, this catalyst significantly accelerated the Volmer step and the Tafel step and, consequently, HER kinetics. This catalyst also demonstrated low overpotentials of 19 and 160 mV at current densities of 10 and 1000 mA cm -2 , respectively, in alkaline media and long-term stability superior to that of most state-of-the-art alkaline HER electrocatalysts. This work provides a rational design principle for advanced multi-site catalytic systems, which can realize multi-electron electrocatalytic reactions., (© 2024 Wiley‐VCH GmbH.)

Wood, as a renewable material, has been regarded as an emerging substrate for self-supporting electrodes in large-scale water electrolysis due to numerous merits such as rich pore structure, abundant hydroxyl groups, etc. However, poor conductivity of wood can greatly suppress the performance of wood-based electrodes. Carbonization process can improve wood's conductivity, but the loss of hydroxyl groups and the required high energy consumption are the drawbacks of such a process. Here, a facile strategy is developed to prepare pristine wood-supported electrode (Ni-NiP/W) for enhanced hydrogen evolution reaction (HER); this improves electrical conductivity of wood while retaining its excellent intrinsic properties. The preparation process involves the deposition of copper on the untreated wood followed with the loading of Ni-NiP catalyst at room temperature. Encouragingly, the Ni-NiP/W exhibits conductive and inherited pristine wood's superhydrophilic and superaerophobic properties, that effectively boost mass and charge transfer. It demonstrates high activity and excellent stability in acidic, alkali, and seawater conditions as well as high current densities of up to 2000 mA cm -2 ; particularly a record-low HER overpotential of 206 mV in acidic conditions at 1000 mA cm -2 . This work fully unlocks the admiring potential of pristine wood as superior substrate for high-performance electrochemical electrodes., (© 2024 Wiley‐VCH GmbH.)

Ammonia (NH 3 ) synthesis via the nitrate reduction reaction (NO 3 RR) offers a competitive strategy for nitrogen cycling and carbon neutrality; however, this is hindered by the poor NO 3 RR performance under high current density. Herein, it is shown that boron-doped Ti 3 C 2 T x MXene nanosheets can highly efficiently catalyze the conversion of NO 3 RR-to-NH 3 at ambient conditions, showing a maximal NH 3 Faradic efficiency of 91% with a peak yield rate of 26.2 mgh -1  mg cat. -1 , and robust durability over ten consecutive cycles, all of them are comparable to the best-reported results and exceed those of pristine Ti 3 C 2 T x MXene. More importantly, when tested in a flow cell, the designed catalyst delivers a current density of ‒1000 mA cm -2 at a low potential of ‒1.18 V versus the reversible hydrogen electrode and maintains a high NH 3 selectivity over a wide current density range. Besides, a Zn-nitrate battery with the catalyst as the cathode is assembled, which achieves a power density of 5.24 mW cm -2 and a yield rate of 1.15 mgh -1  mg cat. -1 . Theoretical simulations further demonstrate that the boron dopants can optimize the adsorption and activation of NO 3 RR intermediates, and reduce the potential-determining step barrier, thus leading to an enhanced NH 3 selectivity., (© 2024 Wiley‐VCH GmbH.)

Sodium-ion batteries (SIBs) are a promising substitute for lithium batteries due to their abundant resources and low cost. Metal sulfides are regarded as highly attractive anode materials due to their superior mechanical stability and high theoretical specific capacity. Guided by the density functional theory (DFT) calculations, 3D porous network shaped Sb 2 S 3 /FeS 2 composite materials with reduced graphene oxide (rGO) through a simple solvothermal and calcination method, which is predicted to facilitate favorable Na + ion diffusion, is synthesized. Benefiting from the well-designed structure, the resulting Sb 2 S 3 /FeS 2 exhibit a remarkable reversible capacity of 536 mAh g -1 after 2000 cycles at a current density of 5 A g -1 and long high-rate cycle life of 3000 cycles at a current density of 30 A g -1 as SIBs anode. In situ and ex situ analyses are carried out to gain further insights into the storage mechanisms and processes of sodium ions in Sb 2 S 3 /FeS 2 @rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique structure and the heterogeneous interface between Sb 2 S 3 and FeS 2 . This study illustrates that combining rGO with heterogeneous engineering can provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs., (© 2024 Wiley‐VCH GmbH.)

Fe-doped NiOOH electrocatalysts have attracted wide interest for the exceptional oxygen evolution reaction (OER) performance, but the precise role of Fe doping on the improved intrinsic activity remains unclear. Herein, the molecular probe technique combined with density functional theory calculation is used to reveal the influence of the Fe atom on the rate-determining step of the OER reaction, where the pre-catalyst of hierarchical self-supporting NiFe layered double hydroxide [LDH] nanosheets equipped on nickel foam (NiFe LDH/NF) is generated via a facile and industrially well-matched one-pot corrosion method. The physical characterization results reveal the reconstruction of NiFe LDH into Fe-doped NiOOH for promoted OER, which has a lower OH* adsorption energy with fast subsequent steps that help in obtaining an improved charge injection efficiency compared to NiOOH. In addition, more exposed electroactive species and facile delivery of mass/electron inside the catalytic procedure actually have a high-quality contribution to the outstanding catalytic activity. Therefore, the NiFe LDH 36 /NF electrocatalyst provides high catalytic activities of 241 and 320 mV at 10 mA cm -2 toward the OER and overall water-splitting in 1 m KOH. This work provides a promising avenue for the rational design of durable self-supporting electrodes toward large-scale water splitting., (© 2024 Wiley‐VCH GmbH.)

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)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The alkaline hydrogen evolution reaction (HER) is limited by scarce proton availability, resulting in slower reaction kinetics compared to those under acidic conditions. Enhancing the local chemical environment of protons on the catalyst surface can improve the intrinsic reaction kinetics. Here, we design a Mo/MoO 2 metallic heterojunction that creates an acidic-like environment with a proton-rich surface, significantly enhancing HER performance in alkaline electrolytes, as confirmed by in situ spectroscopy and electrochemical analysis. A self-standing Mo/MoO 2 catalytic electrode is fabricated via a controlled pyrolysis-reduction strategy. This electrode exhibits exceptional HER activity, with low overpotentials of 65 mV at 10 mA cm -2 and 315 mV at 500 mA cm -2 , a Tafel slope of 38.2 mV dec -1 , and stability exceeding 60 h at -300 mA cm -2 in alkaline solution. The porous flake array structure of the Mo/MoO 2 heterojunctions enhances the adjacent hydronium (H 3 O + ) concentration, resulting in a Δ G H* value of 0.15 eV and a water dissociation energy barrier of 0.37 eV in an alkaline medium. The successful preparation of a large-area electrode (2 cm × 2 cm) demonstrates the scalability of this approach for fabricating molybdenum-based catalytic electrodes with enhanced HER activity in alkaline environments.

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., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Ta-doped Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) for solid-state lithium batteries demonstrates encouraging performance; however, they encounter issues with lithium dendrite formation that impede their widespread use. Herein, we design a LLZTO ceramic with an interlayer containing a mixed dense layer of Ag and LLZTO, prepared by one-step sintering. The Ag-rich interlayer in LLZTO can hinder the growth and the penetration of lithium dendrites though the reaction between Ag and lithium metal. Compared with the Ag-free counterpart, a higher critical current density of 0.6 mA cm -2 , in addition to a longer life span under a current density of 0.2 mA cm -2 , is achieved by adopting the interlayer in LLZTO. This research offers novel insights into the engineering of garnet-based solid electrolytes, tailored for the advancement of high-rate lithium metal batteries.

Gas-evolving reactions (GERs) are important in many electrochemical energy conversion technologies and chemical industries. The operation of GERs at high current densities is critical for their industrial implementation but remains challenging as it poses stringent requirements on the electrodes in terms of reaction kinetics, mass transfer, and electron transport. Here the general and rational design of self-standing carbon electrodes with vertically aligned porous channels, appropriate pore size distribution, and high surface area as supports for loading a variety of catalytic species by facile electrodeposition are reported. These electrodes simultaneously possess high intrinsic activity, large numbers of active sites, and efficient transport highways for ions, gases, and electrons, resulting in significant performance improvements at high current densities in diverse GERs such as urea oxidation, hydrogen evolution, and oxygen evolution reactions, as well as overall urea/water electrolyzers. As an example, the carbon electrode decorated with Ni(OH) 2 demonstrates a record-high current density of 1000 mA cm -2 at 1.360 V versus the reversible hydrogen electrode, largely outperforming the conventional nickel foam-based counterpart and the state-of-the-art electrodes., (© 2024 Wiley‐VCH GmbH.)

A heterojunction photo-electrode(s) consisting of porous black titanium oxide (bTiO 2 ) and electrochemically self-activated TaS 2 flakes is proposed and utilized for hydrogen evolution reaction (HER). The self-activated TaS 2 flakes provide abundant catalytic sites for HER and the porous bTiO 2 , prepared by electrochemical anodization and subsequent reduction serves as an efficient light absorber, providing electrons for HER. Additionally, Au nanostructures are introduced between bTiO 2 and TaS 2 to facilitate the charge transfer and plasmon-triggering ability of the structure created. After structure optimization, high HER catalytic activity at acidic pH and excellent HER activity at neutral pH are achieved at high current densities. In particular, with the utilization of bTiO 2 @TaS 2 photoelectrode (neutral electrolyte, sunlight illumination) current densities of 250 and 500 mA cm -2 are achieved at overpotentials of 433, and 689 mV, respectively, both exceeding the "benchmark" Pt. The addition of gold nanostructures further reduces the overpotential to 360 and 543 mV at 250 and 500 mA cm -2 , respectively. The stability of the prepared electrodes is investigated and found to be satisfying within 24 h of performance at high current densities. The proposed system offers an excellent potential alternative to Pt for the development of green hydrogen production on an industrial scale., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Electrolyte cations have been demonstrated to effectively enhance the rate and selectivity of the electrochemical CO 2 reduction reaction (CO 2 RR), 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 CO 2 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 *CO 2 - 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 CO 2 RR., (© 2024 Wiley-VCH GmbH.)

Metal halide perovskite semiconductors hold a strong promise for enabling thin-film laser diodes. Perovskites distinguish themselves from other non-epitaxial media primarily through their ability to maintain performance at high current densities, which is a critical requirement for achieving injection lasing. Coming in a wide range of varieties, numerous perovskites delivered low-threshold optical amplified spontaneous emission and optically pumped lasing when combined with a suitable optical cavity. A progression toward electrically pumped lasing requires the development of efficient light-emitting structures with reduced optical losses and high radiative efficiency at lasing-level current densities. This involves a set of important trade-offs in terms of material choice, stack and waveguide design, as well as resonator integration. In this Perspective, the key milestones are highlighted that have been achieved in the study of passive optical waveguides and light-emitting diodes, and these learnings are translated toward more complex laser diode architectures. Finally, a novel resonator integration route is proposed that is capable of relaxing optical and electrical design constraints., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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., (© 2024 Wiley-VCH GmbH.)

Electrocatalytic nitrate reduction to ammonia (NO 3 RR) is very attractive for nitrate removal and ammonia production in industrial processes. However, the nitrate reduction reaction is characterized by intense hydrogen competition at strong reduction potentials, which greatly limits the Faraday efficiency at strong reduction potentials. Herein, we reported an Au x Cu single-atom alloy aerogels (Au x Cu SAAs) with three-dimensional network structure with significant nitrate reduction performance of Faraday efficiency (FE) higher than 90 % over a wide potential range (0 ~ -1 V RHE ). The FE of the catalyst was close to 100 % at a high reduction potential of -0.8 V RHE , accompanying with NH 3 yield reaching 6.21 mmol h 1  cm 2 . More importantly, the catalyst maintained a long-term operation over 400 h at 400 mA cm 2 for the NO 3 RR using a continuous flow system in a H-cell. Experimental and theoretical analysis demonstrate that the catalyst can lower the energy barrier for the hydrogenation reaction of *NO 2 , leading to a rapid consumption of the generated *H, facilitate the hydrogenation process of NO 3 RR, and inhibit the competitive HER at high overpotentials, which efficiently promotes the nitrate reduction reaction, especially in industrial applications., (© 2024 Wiley-VCH GmbH.)

Herein, we propose a platinization strategy for the preparation of Pt/X catalysts with low Pt content on substrates possessing electron-rich sites (Pt/X: X = Co 3 O 4 , NiO, CeO 2 , Covalent Organic Framework (COF), etc.). In examples with inorganic and organic substrates, respectively, Pt/Co 3 O 4 possesses remarkable catalytic ability toward HER, achieving a current density at an overpotential of 500 mV that is 3.22 times higher than that of commercial Pt/C. It was also confirmed by using operando Raman spectroscopy that the enhancement of catalytic activity was achieved after platinization of the COF, with a reduction of overpotential from 231 to 23 mV at 10 mA cm -2 . Density functional theory (DFT) reveals that the improved catalytic activity of Pt/Co 3 O 4 and Pt/COF originated from the re-modulation of Pt δ+ on the electronic structure and the synergistic effect of the interfacial Pt δ+ /electron-rich sites. This work provides a rapid synthesis strategy for the synthesis of low-content Pt catalysts for electrocatalytic hydrogen production.

The adhesion of H 2 bubbles on the electrode surface is one of the main factors limiting the performance of H 2 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 H 2 . The typical feature of this reaction system is that the main site of H 2 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 H 2 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 H 2 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 H 2 evolution current density of 250 mA cm -2 is achieved., (© 2024 Wiley-VCH GmbH.)

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/NiMoO 4 /NF heterogeneous electrocatalyst with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO 4 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/NiMoO 4 /NF not only induces the directional evolution of interfacial H 2 O, but also lowers the d-band center (from -0.43 to -2.22 eV) of a-RuMo/NiMoO 4 /NF, the Gibbs free energy of hydrogen adsorption (ΔG H* , from -1.29 to -0.06 eV), and the energy barrier of HzOR (ΔG N2(g) =1.50 eV to ΔG N2* =0.47 eV). Profiting from these favorable factors, the a-RuMo/NiMoO 4 /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/NiMoO 4 /NF||a-RuMo/NiMoO 4 /NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm -2 ., (© 2024 Wiley-VCH GmbH.)

LiNi 0.8 Mn 0.1 Co 0.1 O 2 with high nickel content plays a critical role in enabling lithium metal batteries (LMBs) to achieve high specific energy density, making them a prominent choice for electric vehicles (EVs). However, ensuring the long-term cycling stability of the cathode electrolyte interfaces (CEIs), particularly at fast-charge conditions, remains an unsolved challenge. The decay mechanism associated with CEIs and electrolytes in LMB at high current densities is still not fully understood. To address this issue, in situ Fourier transform infrared (FTIR) is employed to observe the dynamic process of formation/disappearance/regeneration of CEIs during charge and discharge cycles. These dynamic processes further exacerbate the instability of CEIs as current density increases, leading to rupture and dissolution of CEIs and subsequent deterioration in battery performance because of continuous electrolyte reactions. Additionally, the dynamic changes occurring within individual components of CEIs at different cycling stages and various current densities are also discussed. The results demonstrate that excellent capacity retention at small current density is attributed to enrichment of inorganic compounds (Li 2 CO 3 , LiF, etc.) and rendering better stability and smaller expansion of CEIs. The key to achieving excellent electrochemical performance at high current densities lies on protecting CEIs, mainly inorganic components., (© 2024 Wiley‐VCH GmbH.)

Addition of organic compounds containing O/N heteroatoms to aqueous electrolytes such as ZnSO 4 (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 H 2 O for Zn species tends to adsorb to Zn (002) in a lying manner and participate in the solvation shell of Zn 2+ , 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., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Producing green hydrogen in a cost-competitive manner via water electrolysis will make the long-held dream of hydrogen economy a reality. Although platinum (Pt)-based catalysts show good performance toward hydrogen evolution reaction (HER), the high cost and scarce abundance challenge their economic viability and sustainability. Here, a non-Pt, high-performance electrocatalyst for HER achieved by engineering high fractions of stacking fault (SF) defects for MoNi 4 /MoO 2 nanosheets (d-MoNi) through a combined chemical and thermal reduction strategy is shown. The d-MoNi catalyst offers ultralow overpotentials of 78 and 121 mV for HER at current densities of 500 and 1000 mA cm -2 in 1 M KOH, respectively. The defect-rich d-MoNi exhibits four times higher turnover frequency than the benchmark 20% Pt/C, together with its excellent durability (> 100 h), making it one of the best-performing non-Pt catalysts for HER. The experimental and theoretical results reveal that the abundant SFs in d-MoNi induce a compressive strain, decreasing the proton adsorption energy and promoting the associated combination of *H into hydrogen and molecular hydrogen desorption, enhancing the HER performance. This work provides a new synthetic route to engineer defective metal and metal alloy electrocatalysts for emerging electrochemical energy conversion and storage applications., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

In recent years, ceramic cells based on high proton conductivity have attracted much attention and can be employed for hydrogen production and electricity generation, especially at low temperatures. Nevertheless, attaining a high power output and durability is challenging, especially at low operational temperatures. In this regard, we design semiconductor heterostructure SFT-ZnO (SrFe 0.3 TiO 3 -ZnO) materials to function as an electrolyte for fuel cell and electrolysis applications. Using this approach, the functional semiconductor heterostructure can deliver a better power output and high ionic and proton conductivity at low operational temperatures. The prepared cell in fuel cell mode has demonstrated excellent performance of 700 mW cm -2 and proton performance of 540 mW cm -2 at the low temperature of 520 °C, suggesting dominant proton conduction. Further, the prepared cell delivers exceptional current densities of 1.18 and 0.38 A cm -2 (at 1.6 and 1.3 V, respectively) at 520 °C in the electrolysis mode. Our electrochemical cell is stable in fuel and electrolysis mode at a low temperature of 500 °C.

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.

Developing catalysts with suitable adsorption energy for oxygen-containing intermediates and elucidating their internal structure-performance relationships are essential for the commercialization of Li-O 2 batteries (LOBs), especially under high current densities. Herein, NiCo 2 O 4 -CeO 2 heterostructure with a spontaneous built-in electric field (BIEF) is designed and utilized as a cathode catalyst for LOBs at high current density. The driving mechanism of electron pumping/accumulation at heterointerface is studied via experiments and density functional theory (DFT) calculations, elucidating the growth mechanism of discharge products. The results show that BIEF induced by work function difference optimizes the affinity for LiO 2 and promotes the formation of nano-flocculent Li 2 O 2 , thus improving LOBs performance at high current density. Specifically, NiCo 2 O 4 -CeO 2 cathode exhibits a large discharge capacity (9546 mAh g -1 at 4000 mA g -1 ) and high stability (>430 cycles at 4000 mA g -1 ), which are better than the majority of previously reported metal-based catalysts. This work provides a new method for tuning the nucleation and decomposition of Li 2 O 2 and inspires the design of ideal catalysts for LOBs to operate at high current density., (© 2024 Wiley‐VCH GmbH.)

Presented here is an electrochemical three-electrode Gas Diffusion Electrode (GDE) cell tailored for operandoand in situ investigations of electrocatalytic processes, with a particular focus on X-ray scattering studies. The optimized cell is engineered to accommodate the minimal sample-detector distances requisite for comprehensive X-ray total scattering investigations. An in-depth understanding of catalytic processes requires their study under 'working' conditions. Configured as a flow-cell, the setup therefore enables the examination of electrocatalysts under high current densities and associated gas evolution phenomena, particularly pertinent for reactions like the oxygen evolution reaction (OER). Notably, its transparency simplifies cell alignment, troubleshooting, and facilitates scans through the catalyst layer, crucial for background corrections. Demonstrating its versatility, we showcase its utility through Small Angle X-ray Scattering (SAXS), X-ray Diffraction (XRD), and X-ray Pair Distribution Function (PDF) analyses of total scattering data., (Copyright 2024 Gustav K. H. Wiberg, Rebecca K. Pittkowski, Stefanie Punke , Olivia Aalling-Frederiksen , Kirsten M. Ø. Jensen, Matthias Arenz. License: This work is licensed under a Creative Commons Attribution 4.0 International License.)

Developing robust electrodes with high catalytic performance is a key step for expanding practical HER (hydrogen evolution reaction) applications. This paper reports on novel porous Mo 2 C-based ceramics with oriented finger-like holes directly used as self-supported HER electrodes. Due to the suitable MoO 3 sintering additive, high-strength (55 ± 6 MPa) ceramic substrates and a highly active catalytic layer are produced in one step. The in situ reaction between MoO 3 and Mo 2 C enabled the introduction of O in the Mo 2 C crystal lattice and the formation of Mo 2 C(O)/MoO 2 heterostructures. The optimal Mo 2 C-based electrode displayed an overpotential of 333 and 212 mV at 70 °C under a high current intensity of 1500 mA cm -2 in 0.5 m H 2 SO 4 and 1.0 m KOH, respectively, which are markedly better than the performance of Pt wire electrode; furthermore, its price is three orders of magnitude lower than Pt. The chronopotentiometric curves recorded in the 50 - 1500 mA cm -2 range, confirmed its excellent long-term stability in acidic and alkaline media for more than 260 h. Density functional theory (DFT) calculations showed that the Mo 2 C(O)/MoO 2 heterostructures has an optimum electronic structure with appropriate *H adsorption-free energy in an acidic medium and minimum water dissociation energy barrier in an alkaline medium., (© 2023 Wiley‐VCH GmbH.)

Electrocatalysts with low Pt loading mass to achieve high current density (≥1 A cm -2 ) for hydrogen evolution reaction (HER) are still extremely challenging due to the limited intrinsic activity and weak stability of catalytic sites. The modulation of the electronic microenvironment of the support-Pt structure is crucial to enhance the intrinsic activity and stability of catalytic sites. Herein, an innovative titanium oxycarbide (Ti V CO) solid solution with Ti vacancies (Ti V ) is proposed as support to anchor sub-nanoscale Pt atomic clusters (Pt ACs) and a stable "Ti V -Pt ACs" structure is carefully designed. The electronic microenvironment of "Ti V -Pt ACs" is indirectly optimized by an unsaturated C/O site near Ti V . Thanks to this, novel "Ti V -Pt ACs" structure (Pt@Ti V CO) with low Pt loading mass (2.44 wt.%) exhibits excellent HER activity in acidic solution and the mass activity is more than ten times that of commercial 20% Pt/C at the overpotentials of 50 and 100 mV. Particularly, Pt@Ti V CO shows amazing stability at high and fluctuating current density of 1-2 A cm -2 for 120 h. This work provides a novel and promising method to develop stable and low-loading Pt-based catalysts adapting to high current density., (© 2023 Wiley‐VCH GmbH.)

Graphene is atomically thin, possesses excellent thermal conductivity, and is able to withstand high current densities, making it attractive for many nanoscale applications such as field-effect transistors, interconnects, and thermal management layers. Enabling integration of graphene into such devices requires nanostructuring, which can have a drastic impact on the self-heating properties, in particular at high current densities. Here, we use a combination of scanning thermal microscopy, finite element thermal analysis, and operando scanning transmission electron microscopy techniques to observe prototype graphene devices in operation and gain a deeper understanding of the role of geometry and interfaces during high current density operation. We find that Peltier effects significantly influence the operational limit due to local electrical and thermal interfacial effects, causing asymmetric temperature distribution in the device. Thus, our results indicate that a proper understanding and design of graphene devices must include consideration of the surrounding materials, interfaces, and geometry. Leveraging these aspects provides opportunities for engineered extreme operation devices.

The development of facile methods for constructing highly active, cost-effective catalysts that meet ampere-level current density and durability requirements for an oxygen evolution reaction is crucial. Herein, a general topochemical transformation strategy is posited: M-Co 9 S 8 single-atom catalysts (SACs) are directly converted into M-CoOOH-TT (M = W, Mo, Mn, V) pair-sites catalysts under the role of incorporating of atomically dispersed high-valence metals modulators through potential cycling. Furthermore, in situ X-ray absorption fine structure spectroscopy is used to track the dynamic topochemical transformation process at the atomic level. The W-Co 9 S 8 breaks through the low overpotential of 160 mV at 10 mA cm -2 . A series of pair-site catalysts exhibit a large current density of approaching 1760 mA cm -2 at 1.68 V vs reversible hydrogen electrode (RHE) in alkaline water oxidation and achieve a ≈240-fold enhancement in the normalized intrinsic activity compare to that reported CoOOH, and sustainable stability of 1000 h. Moreover, the O─O bond formation is confirmed via a two-site mechanism, supported by in situ synchrotron radiation infrared and density functional theory (DFT) simulations, which breaks the limit of adsorption-energy scaling relationship on conventional single-site., (© 2024 Wiley‐VCH GmbH.)

The high-current-density Zn-air battery shows big prospects in next-generation energy technologies, while sluggish O 2 reaction and diffusion kinetics barricade the applications. Herein, the sequential assembly is innovatively demonstrated for hierarchically mesoporous molybdenum carbides/carbon microspheres with a tunable thickness of mesoporous carbon layers (Meso-Mo 2 C/C-x, where x represents the thickness). The optimum Meso-Mo 2 C/C-14 composites (≈2 µm in diameter) are composed of mesoporous nanosheets (≈38 nm in thickness), which possess bilateral mesoporous carbon layers (≈14 nm in thickness), inner Mo 2 C/C layers (≈8 nm in thickness) with orthorhombic Mo 2 C nanoparticles (≈2 nm in diameter), a high surface area of ≈426 m 2  g -1 , and open mesopores (≈6.9 nm in size). Experiments and calculations corroborate the hierarchically mesoporous Mo 2 C/C can enhance hydrophilicity for supplying sufficient O 2 , accelerate oxygen reduction kinetics by highly-active Mo 2 C and N-doped carbon sites, and facilitate O 2 diffusion kinetics over hierarchically mesopores. Therefore, Meso-Mo 2 C/C-14 outputs a high half-wave potential (0.88 V vs RHE) with a low Tafel slope (51 mV dec -1 ) for oxygen reduction. More significantly, the Zn-air battery delivers an ultrahigh power density (272 mW cm -2 ), and an unprecedented 100 h stability at a high-current-density condition (100 mA cm -2 ), which is one of the best performances., (© 2023 Wiley‐VCH GmbH.)

Water electrolysis is emerging as a promising renewable-energy technology for the green production of hydrogen, which is a representative and reliable clean energy source. From economical and industrial perspectives, the development of earth-abundant non-noble metal-based and bifunctional catalysts, which can simultaneously exhibit high catalytic activities and stabilities for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), is critical; however, to date, these types of catalysts have not been constructed, particularly, for high-current-density water electrolysis at the industrial level. This study developed a heterostructured zero-dimensional (0D)-one-dimensional (1D) PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF)-Ni 3 S 2 as a self-supported catalytic electrode via interface and morphology engineering. This unique heterodimensional nanostructure of the PBSCF-Ni 3 S 2 system demonstrates superaerophobic/superhydrophilic features and maximizes the exposure of the highly active heterointerface, endowing the PBSCF-Ni 3 S 2 electrode with outstanding electrocatalytic performances in both HER and OER and exceptional operational stability during the overall water electrolysis at high current densities (500 h at 500 mA cm -2 ). This study provides important insights into the development of catalytic electrodes for efficient and stable large-scale hydrogen production systems.

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 η ORR and η OER 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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Precise morphology design and electronic structure regulation are critically significant to promote catalytic activity and stability for electrochemical hydrogen production at high current density. Herein, the carbon nanotube (CNT) encapsulated Fe-doped NiCoP nanoparticles is in-situ grown in hierarchical carbonized wood (NCF 0.5 P@CNT/CW) for water splitting. Coupling merits of porous carbonized wood (CW) substrate, CNT encapsulating and Fe doping, the NCF 0.5 P@CNT/CW features remarkable and durable electrocatalytic activity. The overpotentials of NCF 0.5 P@CNT/CW at 50 mA cm -2 mV and 205 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) and features high current density of 800 mA cm -2 within 300 mV for both OER and HER. Moreover, NCF 0.5 P@CNT/CW displays outstanding overall water splitting performance (η 50 = 1.62 V and η 100 = 1.67 V), outperforming Pt/C║RuO 2 (η 50 = 1.74 V), and can achieve the current density of 700 mA cm -2 at a lower cell voltage of 1.78 V. Overpotential is only 4.0 % decay after 120 h measurement at 50 mA cm -2 . Density functional theory (DFT) calculations reveals Fe doping optimizes the binding energy and Gibbs free energy of intermediates, and regulates d-band center of NCF 0.5 P@CNT/CW. Such synergistic strategy of morphology manipulation and electronic structure optimization provides a spark for developing effective and robust bifunctional catalysts., (© 2023 Wiley-VCH GmbH.)

The electrosynthesis of hydrogen peroxide (H 2 O 2 ) via two-electron (2e - ) oxygen (O 2 ) 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 H 2 O 2 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 H 2 O 2 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 O 2 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 H 2 O 2 further illustrated the promising practical application., (© 2023 Wiley-VCH GmbH.)

Lithium-sulfur (Li-S) batteries hold the superiority of eminent theoretical energy density (2600 Wh kg -1 ). However, the ponderous sulfur reduction reaction and the issue of polysulfide shuttling pose significant obstacles to achieving the practical wide-temperature operation of Li-S batteries. Herein, a covalent organic nanosheet-wrapped carbon nanotubes (denoted CON/CNT) composite is synthesized as an electrocatalyst for wide-temperature Li-S batteries. The design incorporates the CON skeleton, which contains imide and triazine functional units capable of chemically adsorbing polysulfides, and the underlaid CNTs facilitate the conversion of captured polysulfides enabled by enhanced conductivity. The electrocatalytic behavior and chemical interplay between polysulfides and the CON/CNT interlayer are elucidated by in situ X-ray diffraction detections and theoretical calculations. Resultantly, the CON/CNT-modified cells demonstrate upgraded performances, including wide-temperature operation ranging from 0 to 65 °C, high-rate performance (625 mAh g -1 at 5.0 C), exceptional high-rate cyclability (1000 cycles at 5.0 C), and stable operation under high sulfur loading (4.0 mg cm -2 ) and limited electrolyte (5 µL mg s -1 ). These findings might guide the development of advanced Li-S batteries., (© 2023 Wiley-VCH GmbH.)

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 Mo 2 C-Mo 2 N 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 Mo 2 C/Mo 2 N triggering highly active interfacial sites with a nearly zero ∆ G H* 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 Mo 2 C-Mo 2 N. Consequently, the self-supporting Mo 2 C-Mo 2 N@CNWs/D exhibits significantly low overpotentials of 137.8 and 194.4 mV at high current densities of 500 and 1000 mA/cm 2 , 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.

Adopting renewable electricity to produce "green" hydrogen has been a critical challenge because at a high current density the mass transfer capability of most catalytic electrodes deteriorates significantly. Herein, a unique lamellar fern-like alloy aerogel (LFA) electrode, showing a unique dynamically adaptive bubbling capability and can effectively avoid stress concentration caused by bubble aggregation is reported. The LFA electrode is intrinsically highly catalytic-active and shows a highly porous, resilient, hierarchically ordered, and well-percolated conductive network. It not only shows superior gas evacuation capability but also exhibits significantly improved stability at high current densities, showing the record lowest oxygen evolution reaction (OER) overpotential of 244 mV at 1000 mA cm -2 and stably over 6000 h. With the merits of mechanical robustness, excellent electron transport, and efficient bubble evacuation, LFA can be self-standing catalytic electrode and gas diffusion layers in anion-exchange-membrane water electrolysis (AEMWE), which can achieve 3000 mA cm -2 at a low voltage of 1.88 V and can sustain stable electrolysis at 2000 mA cm -2 for over 1300 h. This strategy can be extended to various gas evolution reactions as a general design rule for multiphase catalysis applications., (© 2023 Wiley-VCH GmbH.)

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 ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Designing heterojunction catalysts with energy effects at the interface, particularly combining the surface structure advantages of super-hydrophilic interfaces with the high activity advantages of bimetal synergistic optimisation, is the key to developing economical and efficient industrial electrocatalytic water-splitting catalysts. In this study, a coupled nanoflower-like NiFe(OH) x /(Ni, Fe)Se heterostructure catalyst supported on Ni foam (NF) (NFSe@NFOH/NF) was designed and successfully prepared using hydrothermal and electrodeposition strategies. Owing to the electron interaction at the heterogeneous amorphous (NFOH)/crystalline (NFSe) interface and the bimetallic synergistic effect of Ni and Fe, the prepared NFSe@NFOH/NF exhibited excellent and stable oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalytic properties, with low overpotentials of 214/276 mV at 100 mA⋅cm -2 and 262/340 mV at 500 mA⋅cm -2 . The assembled water electrolyser comprising NFSe@NFOH/NF || NFSe@NFOH/NF needed only small voltages of 1.73 and 1.85 V to yield current densities of 100 and 500 mA⋅cm -2 , respectively. This study offers an innovative design idea for the rational adoption of interface engineering and amorphous-crystalline engineering techniques to construct catalysts with excellent catalytic activity and stability for electrocatalytic overall water splitting (EOWS) at a high current density, which further facilitates the advancement of sustainable energy technology in the future., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The robust and scalable oxygen evolution electrocatalysts that can deliver high current densities at low applied potential is a great challenge for the large-scale industrial application in hydrogen production. Here, the preparation of a grain-boundary-rich Ni-Fe (oxy)hydroxide catalyst on Ni foam is reported using a scalable coating approach followed by a chemical precipitating treatment. This facile method effectively assembles the hierarchical Ni-Fe (oxy)hydroxide nanosheet in the ultrasmall crystalline domains (<4 nm) with rich grain boundaries. The hierarchical nanosheet structure with the grain boundaries provides more accessible catalytic sites, facile charge, and mass transfer. Benefiting from the abundant grain boundaries in the hierarchical nanosheets, the as-prepared Ni-Fe (oxy)hydroxide electrodes deliver current densities of 500 and 1000 mA cm -2 at overpotentials of only 278 and 296 mV for the oxygen evolution reaction. The prepared electrode also exhibits long-term durability at a high current density in alkaline conditions., (© 2023 Wiley-VCH GmbH.)

Aqueous zinc-ion batteries (AZIBs) offer promising prospects for large-scale energy storage due to their inherent abundance and safety features. However, the growth of zinc dendrites remains a primary obstacle to the practical industrialization of AZIBs, especially under harsh conditions of high current densities and elevated temperatures. To address this issue, a Janus separator with an exceptionally ultrathin thickness of 29 µm is developed. This Janus separator features the bacterial cellulose (BC) layer on one side and Ag nanowires/bacterial cellulose (AgNWs/BC) layer on the other side. High zincophilic property and excellent electric/thermal conductivity of AgNWs make them ideal for serving as an ion pump to accelerate Zn 2+ transport in the electrolyte, resulting in greatly improved Zn 2+ conductivity, deposition of homogeneous Zn nuclei, and dendrite-free Zn. Consequently, the Zn||Zn symmetrical cells with the Janus separator exhibit a stable cycle life of over 1000 h under 80 mA cm -2 and are sustained for over 600 h at 10 mA cm -2 under 50 °C. Further, the Janus separator enables excellent cycling stability in AZIBs, aqueous zinc-ion capacitors (AZICs), and scaled-up flexible soft-packaged batteries. This study demonstrates the potential of functional separators in promoting the application of aqueous zinc batteries, particularly under harsh conditions., (© 2023 Wiley-VCH GmbH.)

The practical application of Li metal anodes (LMAs) is limited by uncontrolled dendrite growth and side reactions. Herein, we propose a new friction-induced strategy to produce high-performance thin Li anode (Li@CFO). By virtue of the in situ friction reaction between fluoropolymer grease and Li strips during rolling, a robust organic/inorganic hybrid interlayer (lithiophilic LiF/LiC 6 framework hybridized -CF 2 -O-CF 2 - chains) was formed atop Li metal. The derived interface contributes to reversible Li plating/stripping behaviors by mitigating side reactions and decreasing the solvation degree at the interface. The Li@CFO||Li@CFO symmetrical cell exhibits a remarkable lifespan for 5,600 h (1.0 mA cm -2 and 1.0 mAh cm -2 ) and 1,350 cycles even at a harsh condition (18.0 mA cm -2 and 3.0 mAh cm -2 ). When paired with high-loading LiFePO 4 cathodes, the full cell lasts over 450 cycles at 1C with a high-capacity retention of 99.9%. This work provides a new friction-induced strategy for producing high-performance thin LMAs., (© 2023. Shanghai Jiao Tong University.)

Electrochemical water splitting is a promising approach for producing sustainable and clean hydrogen. Typically, high valence state sites are favorable for oxidation evolution reaction (OER), while low valence states can facilitate hydrogen evolution reaction (HER). However, here we proposed a high valence state of Co 3+ in Ni 9.5 Co 0.5 -S-FeO x hybrid as the favorable center for efficient and stable HER, while structural analogues with low chemical states showed much worse performance. As a result, the Ni 9.5 Co 0.5 -S-FeO x catalyst could drive alkaline HER with an ultra-low overpotential of 22 mV for 10 mA cm -2 , and 175 mV for 1000 mA cm -2 at the industrial temperature of 60 °C, with an excellent stability over 300 h. Moreover, this material could work for both OER and HER, with a low cell voltage being 1.730 V to achieve 1000 mA cm -2 for overall water splitting at 60 °C. X-ray absorption spectroscopy (XAS) clearly identified the high valence Co 3+ sites, while in situ XAS during HER and theoretical calculations revealed the favorable electron capture at Co 3+ and suitable H adsorption/desorption energy around Co 3+ , which could accelerate the HER. The understanding of high valence states to drive reductive reactions may pave the way for the rational design of energy-related catalysts., (© 2023 Wiley-VCH GmbH.)

Although single metal atoms on porous carbons (PCs) are widely used in electrochemical CO 2 reduction reaction, these systems have long relied on flat graphene-based models, which are far beyond reality because of abundant curved structures in PCs; the effect of curved surfaces has long been ignored. In addition, the selectivity generally decreases under high current density, which severely limits practical application. Herein, theoretical calculations reveal that a single-Ni-atom on a curved surface can simultaneously enhance the total density of states around Fermi level and decrease the energy barrier for *COOH formation, thereby enhancing catalytic activity. This work reports a rational molten salt approach for preparing PCs with ultra-high specific surface area of up to 2635 m 2 g -1 . As determined by cutting-edge techniques, a single Ni atom on a curved carbon surface is obtained and used as a catalyst for electrochemical CO 2 reduction. The CO selectivity reaches up to 99.8% under industrial-level current density of 400 mA cm -2 , outperforming state-of-the-art PC-based catalysts. This work not only offers a new method for the rational synthesis of single atom catalysts with strained geometry to host rich active sites, but also provides in-depth insights for the origin of catalytic activity of curved structure-enriched PC-based catalysts., (© 2023 Wiley-VCH GmbH.)

Aqueous redox flow battery systems that use a zinc negative electrode have a relatively high energy density. However, high current densities can lead to zinc dendrite growth and electrode polarization, which limit the battery's high power density and cyclability. In this study, a perforated copper foil with a high electrical conductivity was used on the negative side, combined with an electrocatalyst on the positive electrode in a zinc iodide flow battery. A significant improvement in the energy efficiency (ca. 10% vs using graphite felt on both sides) and cycling stability at a high current density of 40 mA cm -2 was observed. A long cycling stability with a high areal capacity of 222 mA h cm -2 is obtained in this study, which is the highest reported areal capacity for zinc-iodide aqueous flow batteries operating at high current density, in comparison to previous studies. Additionally, the use of a perforated copper foil anode in combination with a novel flow mode was discovered to achieve consistent cycling at exceedingly high current densities of >100 mA cm -2 . In situ and ex situ characterization techniques, including in situ atomic force microscopy coupled with in situ optical microscopy and X-ray diffraction, are applied to clarify the relationship between zinc deposition morphology on the perforated copper foil and battery performance in two different flow field conditions. With a portion of the flow going through the perforations, a significantly more uniform and compact zinc deposition was observed compared to the case where all of the flow passed over the surface of the electrode. Results from modeling and simulation support the conclusion that the flow of a fraction of electrolyte through the electrode enhances mass transport, enabling a more compact deposit.

Surface and interface engineering, especially the creation of abundant Cu 0 /Cu + interfaces and nanograin boundaries, is known to facilitate C 2+ production during electrochemical CO 2 reductions over copper-based catalysts. However, precisely controlling the favorable nanograin boundaries with surface structures (e.g., Cu(100) facets and Cu[ n (100)×(110)] step sites) and simultaneously stabilizing Cu 0 /Cu + interfaces is challenging, since Cu + species are highly susceptible to be reduced into bulk metallic Cu at high current densities. Thus, an in-depth understanding of the structure evolution of the Cu-based catalysts under realistic CO 2 RR conditions is imperative, including the formation and stabilization of nanograin boundaries and Cu 0 /Cu + interfaces. Herein we demonstrate that the well-controlled thermal reduction of Cu 2 O nanocubes under a CO atmosphere yields a remarkably stable Cu 2 O-Cu nanocube hybrid catalyst (Cu 2 O(CO)) possessing a high density of Cu 0 /Cu + interfaces, abundant nanograin boundaries with Cu(100) facets, and Cu[ n (100)×(110)] step sites. The Cu 2 O(CO) electrocatalyst delivered a high C 2+ Faradaic efficiency of 77.4% (56.6% for ethylene) during the CO 2 RR under an industrial current density of 500 mA/cm 2 . Spectroscopic characterizations and morphological evolution studies, together with in situ time-resolved attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) studies, established that the morphology and Cu 0 /Cu + interfacial sites in the as-prepared Cu 2 O(CO) catalyst were preserved under high polarization and high current densities due to the nanograin-boundary-abundant structure. Furthermore, the abundant Cu 0 /Cu + interfacial sites on the Cu 2 O(CO) catalyst acted to increase the *CO adsorption density, thereby increasing the opportunity for C-C coupling reactions, leading to a high C 2+ selectivity.