Recent Advances in High-Entropy Layered Oxide Cathode Materials for Alkali Metal-Ion Batteries.

Abstract

Since the electrochemical de/intercalation behavior is first detected in 1980, layered oxides have become the most promising cathode material for alkali metal-ion batteries (Li⁺/Na⁺/K⁺; AMIBs) owing to their facile synthesis and excellent theoretical capacities. However, the inherent drawbacks of unstable structural evolution and sluggish diffusion kinetics deteriorate their electrochemical performance, limiting further large-scale applications. To solve these issues, the novel and promising strategy of high entropy has been widely applied to layered oxide cathodes for AMIBs in recent years. Through multielement synergy and entropy stabilization effects, high-entropy layered oxides (HELOs) can achieve adjustable activity and enhanced stability. Herein, the basic concepts, design principles, and synthesis methods of HELO cathodes are introduced systematically. Notably, it explores in detail the improvements of the high-entropy strategy on the limitations of layered oxides, highlighting the latest advances in high-entropy layered cathode materials in the field of AMIBs. In addition, it introduces advanced characterization and theoretical calculations for HELOs and proposes potential future research directions and optimization strategies, providing inspiration for researchers to develop advanced HELO cathode materials in the areas of energy storage and conversion.