Synthesis and Regulation Mechanism of High Entropy Layered Double Hydroxide Electrocatalyst.

High-entropy layered double hydroxides (HE-LDHs) represent a unique class of two-dimensional materials achieved by combining multicomponent entropy stabilization with layered hydroxide structures. Despite exhibiting the high-entropy effects, lattice distortion effects, hysteretic diffusion effects, and cocktail effects characteristic of high-entropy materials, as well as the stable framework provided by the layered double hydroxide (LDH) structure. However, the intrinsic activity of LDH may be limited, but the high-entropy design has successfully overcome this limitation. The incorporation of multiple metal cations into atomically thin layers of HE-LDHs expands the compositional and electronic design space, enabling flexible tuning of the local coordination environment, electronic structure, and reaction interface, thereby enhancing catalyst activity. This review critically summarizes recent advances in HE-LDHs for electrocatalysis, focusing on their formation mechanisms, synthetic strategies, and structure-performance relationships. Representative synthesis routes, including co-precipitation, hydrothermal/solvothermal method, electrodeposition, metal-organic framework (MOF)-derived conversion, and in situ conversion method, are evaluated in terms of compositional homogeneity, structural control, and scalability. Key performance optimization strategies, such as elemental synergy, defect and interlayer engineering, morphology modulation, conductivity regulation, and interface construction, are discussed to elucidate their roles in enhancing catalytic activity, kinetics, and stability. Finally, emerging theoretical approaches are highlighted as essential tools for decoding entropy-driven effects and guiding the rational design of next-generation two-dimensional high-entropy catalysts for energy conversion.