Sandwich‐Like MXene@Mn₃O₄@PPy Hollow Microspheres Synergistically Enabled Ultra‐long Cycling Life in Aqueous Zinc Ion Batteries

Abstract Manganese‐based oxides are be regarded as one of the most promising cathode materials for aqueous zinc ion batteries (AZIBs). A major restriction of manganese‐based oxides in practical applications is their unsatisfied structural stability due to the irreversible manganese dissolution. Additionally, the poor electrical conductivity also limits the rate capability. Herein, the sandwich‐like MXene@Mn₃O₄@PPy hollow microspheres are constructed via self‐sacrificial template and surface coating method to improve the cycling life of AZIBs. Benefiting from the unique sandwich‐like hollow structure and the surface coating of PPy, the MXene@Mn₃O₄@PPy cathode possesses high electronic/ionic conductivity and satisfied structural stability. The sandwich‐like MXene@Mn₃O₄@PPy hollow microspheres deliver excellent electrochemical performance, including an impressive rate capability and ultra‐long cycling life with a capacity of 120 mAh g⁻¹ at 5 A g⁻¹ after 9000 cycles. In addition, the systematic ex situ XRD and HRTEM characterizations verify the highly reversible Zn²⁺ and H⁺ insertion/desertion in the sandwich‐like MXene@Mn₃O₄@PPy hollow microspheres. This work combines hollow structure design and surface coating method to provide an effective strategy for improving the structural stability of manganese‐based oxides in AZIBs.