High-Entropy Materials for Next-Generation Energy Systems: A Decade of Progress in Synthesis, Properties, and Applications.

The transition to low-carbon energy systems is increasingly constrained by the intrinsic limitations of conventional materials, which often struggle to simultaneously deliver high catalytic activity, long-term stability, and operational durability. Over the past decade, high-entropy materials (HEMs) have emerged as a transformative materials-design paradigm that addresses these challenges by shifting from single-principal-element optimization to entropy-driven stabilization of multicomponent, highly disordered solid solutions. This review critically traces the evolution of functional HEMs from their metallurgical origins to their growing prominence in energy-related ceramic and ionic systems. We elucidate the thermodynamic foundations of the field, examining how the four core effects-high-entropy stabilization, severe lattice distortion, sluggish diffusion, and the cocktail effect-translate into tangible performance enhancements in electrochemical applications. Adopting a structure-centric framework, we highlight recent breakthroughs across key lattice families, including the suppression of cation segregation in high-entropy perovskite cathodes for solid oxide fuel cells, the expansion of redox windows in high-entropy layered double hydroxides for supercapacitors, and the precise electronic tuning of active sites in high-entropy spinels for nitrate reduction electrocatalysis. Furthermore, we assess advances in synthesis strategies, contrasting thermodynamically driven solid-state approaches with kinetically controlled solution-based routes essential for nanoscale engineering.