Yingpeng Xie

Sodium vanadate (NaVO ₃ ) has attracted increasing attention as an anode material for sodium-ion batteries owing to its high theoretical capacity. However, its practical application is severely hindered by poor electronic conductivity and pronounced structural instability during cycling. Here we report an interconnected NaVO ₃ –carbon nanotube (CNT) hybrid architecture in which NaVO ₃ nanostructures are in situ grown along a multi-walled CNT framework via an evaporation-induced solution process. This rationally designed composite establishes continuous electron-transport pathways while mechanically reinforcing the active material against sodiation-induced stress. Comprehensive structural and spectroscopic analyses reveal strong interfacial electronic coupling between NaVO ₃ and CNTs, accompanied by the formation of a hierarchical porous network that facilitates electrolyte infiltration and rapid Na ⁺ diffusion. Although the CNT framework improves the electronic conductivity, Na ⁺ transport kinetics, and initial reversibility of NaVO ₃ , the remaining capacity decay indicates that irreversible structural reconstruction still represents a major limitation for NaVO ₃ -based anodes. In situ X-ray diffraction further uncovers an irreversible crystalline-to-amorphous transition during the first sodiation process, highlighting the critical role of CNT confinement in stabilizing the amorphous NaVO ₃ framework upon cycling. Therefore, this work provides mechanistic insight into the conductivity enhancement and structural degradation behavior of NaVO ₃ , offering useful guidance for the future design of structurally stabilized sodium vanadate anodes.

Proton exchange membrane water electrolysis (PEMWE) is a promising technology for green hydrogen production due to its high efficiency, compact design, and flexible operation. However, the reliance on noble metal‐based anode catalysts significantly increases hydrogen production costs. Transition metal oxides have emerged as alternatives for the acidic oxygen evolution reaction (OER) because of their diverse compositions, tunable structures, and lower cost. This review summarizes recent advances in transition metal oxide catalysts beyond pure IrO ₂ , RuO ₂ , and their mixtures. Fundamental OER mechanisms, including the adsorbate evolution mechanism, lattice oxygen mechanism, and oxide pathway mechanism, are introduced, with emphasis on their roles in regulating catalytic activity and stability. Representative catalyst systems such as spinels, perovskites, pyrochlores, dioxides, and high entropy oxides are systematically reviewed, highlighting performance enhancement strategies including heterostructure construction, elemental doping, and defect engineering. Emerging concepts such as reaction pathway engineering, corrosion suppression, and dynamic structural stability are discussed as effective approaches to overcoming the trade‐off between activity and stability. Finally, current challenges and future perspectives are outlined, with emphasis on artificial intelligence‐assisted catalyst design, characterization optimization, scalable synthesis, and standardized industrial evaluation, to accelerate the practical deployment of advanced acidic OER catalysts in sustainable hydrogen production.

Developing cost‐efficient and robust anodic electrodes for direct seawater electrolysis that can resist chloride‐induced corrosion remains a significant challenge. In this study, a self‐supporting electrode composed of an amorphous FeNi‐based phosphate layer supported on Fe@Ni foam (AL/Fe@Ni) was successfully fabricated via a facile in situ hydrothermal growth method. During the oxygen evolution reaction (OER), the amorphous layer undergoes in situ reconstruction accompanied by the dissolution of phosphate anions, leading to the formation of Fe‐doped Ni(oxy)hydroxide nanosheets. In situ Raman spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy analyses demonstrate that Fe‐ion doping plays a critical role in promoting this reconstruction process. Quantitative analysis of element dissolution and chloride adsorption reveals that the dynamic desorption and re‐adsorption of leached phosphate anions provide the electrode with electrostatic repulsion against chloride ions. Moreover, the redeposition of a small amount of dissolved Fe ions suppresses the dissolution of active elements, establishing a self‐healing mechanism. Theoretical calculations further reveal that the dissociated PO ₄ ³⁻ anions preferentially adsorb onto the surface of the reconstructed Ni(Fe)OOH, promoting more favorable adsorption of OH ⁻ compared to Cl ⁻ due to strong repulsive interactions between anchored PO ₄ ³⁻ and Cl ⁻ . Benefiting from the integrated effects, including the reconstructed highly active phase, suppressed chlorine evolution reaction, self‐healing capability, enhanced mass transfer endowed by superhydrophilic and superaerophobic properties, and inherent anticorrosion behavior, the electrode exhibits high OER selectivity and exceptional durability. This work offers a new perspective for designing and fabricating highly efficient and robust electrodes for seawater electrolysis.

Form-stable phase change materials (PCMs) with enhanced thermal conductivity have attracted wide attention for structural stability and high thermal storage efficiency. However, balancing the trade-off between enthalpy retention and functional enhancement remains a critical challenge. In this work, a semi-interpenetrating polymer network (semi-IPN) composed of sodium polyacrylate (PAAS)/N,N'-methylenebisacrylamide (MBA)/polyethylene glycol (PEG) was innovatively integrated with highly compatible copper nanowires (CuNW) via in-situ doping and free radical polymerization. This rational design yields a composite with boosted thermal conductivity and robust form stability. Notably, CuNW incorporation does not affect its phase change enthalpy (127.6 J/g), while heat storage and release rates are improved by 40.0% and 36.4% respectively. It realizes simultaneous enhancement of thermal conductivity and form stability without sacrificing energy storage density. This work provides a promising strategy for the development of high-performance form-stable PCMs, addressing the long-standing challenge of balancing enthalpy and functionality in thermal energy storage systems.

The initiation of the water splitting reaction necessitates a considerable energy input and the associated energy barrier can be notably mitigated through the utilization of appropriate catalysts. Ni₃N/g‐C₃N₄ catalyst was synthesized through a combination of thermal decomposition and hydrothermal synthesis techniques for photothermal water splitting reaction. The catalyst was characterized using XRD, HRTEM, UV–vis, XPS, electrochemical impedance spectroscopy (EIS), and photoluminescence (PL). It was observed that the Ni₃N promoter is uniformly dispersed on the g‐C₃N₄ exerting no discernible influence on the surface structure and crystal phase of the g‐C₃N₄.The incorporation of Ni₃N effectively decreases the resistance of g‐C₃N₄, enhances the photocurrent intensity, facilitates the transfer of photogenerated electrons from g‐C₃N₄ to Ni₃N, and suppresses the recombination of photogenerated carriers. Additionally, the findings from the photothermal water splitting experiments revealed that g‐C₃N₄ decreased the activation energy to 71.23 kJ·mol⁻¹, while the Ni₃N promoter further lowered it to 19.73 kJ·mol⁻¹.