Design strategies for high entropy materials in water electrolysis: Enhancing activity, stability, and reaction kinetics

This review aims to establish general guidelines for designing highly active high-entropy materials (HEMs) with respect to lattice choice, component selection, and samorphological design, leading to the optimization of reaction kinetics and catalytic activity. HEMs have shown superior catalytic performance in hydrogen and oxygen evolution reactions because of their high-entropy structure of multielement random mixing, tailored chemical compositions, and tunable functional characteristics. However, the catalytic applications of HEMs are limited by structural instability, limited catalytic efficiency, and low conductivity, as well as their inherently complex and poorly controlled surface configurations. This review briefly introduces the characteristics of HEMs, highlighting their potential as electrocatalysts, which stems from their unique thermodynamic properties resulting from the collective interactions of multiple elements in the lattice. Then, approaches for enhancing the performance of HEMs are discussed, including composition selection, strain engineering, defect introduction, morphology control, support use, and the role of computational methods, particularly in guiding composition selection. Unlike prior reviews focusing on individual aspects of HEMs, this review systematically integrates computational-guided composition screening, defect engineering, strain modulation, and morphological control with thermodynamic-kinetic stability analysis, offering a holistic design framework that bridges multi-element synergy, surface optimization, and electronic structure tuning for practical electrocatalysis. Additionally, the discussion of stability is grounded in the thermodynamic principles of high entropy and the kinetics of slow diffusion. Finally, insights into challenges and prospects, including <i>in situ</i> characterization techniques, emerging computational methods, and scalability, are outlined to guide future advanced design strategies and fabrication technologies.