Hollow Multishelled High Entropy Oxide with Inert Aluminum Stabilizer for Boosted Electrochemical Lithium Storage

Abstract High entropy oxides (HEOs) have gained increasing attention as lithium‐ion battery anodes, owing to their multi‐principal synergistic effect and structural stability. However, the conversion type HEOs also suffer from low intrinsic conductivity, volume expansion, and slow kinetics as the traditional metal oxide. Herein, a (FeCoNiCrMn) 2 O 3 HEO with a hollow multishelled structure and Al‐doping (Al‐HEO‐HoMS) is successfully prepared by a thermal diffusion‐assisted template method. The hollow multishelled structure effectively accommodates the volume changes and mitigates structural strains, resulting in excellent electrochemical stability. Most importantly, the inserted Al dopant in Al‐HEO‐HoMS serves as a pegging points, securely fastening other metallic elements by Al─O bonds to maintain the structural stability of anodes during repeated lithiation/delithiation. Additionally, the abundant oxygen vacancies and the optimized electronic structure brought by Al doping have been validated to accelerate the lithiation kinetics. Consequently, the Al‐HEO‐HoMS anode exhibits a high reversible capacity of 1540 mAh g −1 after 500 cycles at 1 A g −1 . The combination of inert metal doping and structural regulation of HEO is expected to alleviate the volume expansion and slow kinetics problem, offering a universal strategy for designing HEO anodes for advanced lithium‐ion batteries.