High‐Performance Aqueous Zinc‐Ion Battery Based on an Al0.35Mn2.52O4 Cathode: A Design Strategy from Defect Engineering and Atomic Composition Tuning

Abstract Rechargeable zinc‐ion batteries (ZIBs), which adopt mild aqueous electrolytes with high power density and safety, have received significant interest. As the most widely used cathode material for ZIBs, manganese‐based oxide has poor rate performance owing to its low electronic conductivity and slow ion diffusion kinetics. In this study, using the synergistic regulation strategy of defect engineering and atomic composition tuning, a mesoporous Al 0.35 Mn 2.52 O 4 with an ultrahigh surface area (up to 82 m 2 g −1 ) is fabricated through Al substitution in the Mn 3 O 4 , followed by an Al‐selective leaching process. During the entire process, numerous defects are obtained in the spinel structure by removing ≈30% of the Al cations. Al substitution can improve the material conductivity, while cation defects can weaken the electrostatic effect and promote ion diffusion ability. Therefore, the Al 0.35 Mn 2.52 O 4 cathode of ZIBs exhibits a high reversible capacity of 302 mAh g −1 at a current density of 100 mA g −1 . Furthermore, the reversible capacity remains at 147 mAh g −1 after 1000 cycles at a current density of 1500 mA g −1 . This synergistic regulation of atomic composition tuning and defect engineering provides a new perspective for improving the performance of electrode materials in ZIBs.