Designing High Reversibility Free‐Standing Hierarchical Porous High‐Entropy Oxide as Anodes for Advanced Lithium‐Ion Batteries

Abstract Designing high‐entropy oxides (HEOs) anodes with fast reaction kinetics and superior cycling stability for lithium‐ion battery energy storage is extremely promising but still challenging. Little attention has been paid to solving the poor cyclability caused by structural damage and volume expansion by optimizing the structural design strategies of HEOs. Herein, a free‐standing hierarchical porous high‐entropy alloy (HEA)/oxide (hp‐HEA/HEO) anode is prepared by melt‐dealloying and solution treatment method. The origins of rapid ion diffusion and electron transport, as well as cyclability, are systematically illustrated by different levels of synergy. Specifically, the hierarchical porous structure buffers the volume expansion (only 12.9%) at macroscopic, and the microcrystalline stabilization mechanism benefiting from high‐entropy effects is responsible for the overall frame during cycling at the microscopic level. As a result, the hp‐HEA/HEO exhibits satisfactory performance with 7.42 mAh cm⁻² at 0.5 mA cm⁻² and capacity retention of 98% at 1.0 mA cm⁻² after 100 cycles. This work provides a new idea for designing advanced HEO anode materials in structure and composition for energy storage‐related applications.