Superior-Performance Aqueous Zinc-Ion Batteries Based on the <i>In Situ</i> Growth of MnO₂ Nanosheets on V₂CT_X MXene

Abstract

Mn-based aqueous zinc-ion batteries (ZIBs) are promising candidate for large-scale rechargeable energy storage because of easy fabrication, low cost, and high safety. Nevertheless, the commercial application of Mn-based cathode is hindered by the challenging issues of low rate capability and poor cyclability. Herein, a manganese-vanadium hybrid, K-V₂C@MnO₂ cathode, featured with MnO₂ nanosheets uniformly formed on a V₂CT_X MXene surface, is elaborately designed and synthesized by metal-cation intercalation and following <i>in situ</i> growth strategy. Benefiting from the hybrid structure with high conductivity, abundant active sites, and the synergistic reaction of Mn²⁺ electrodeposition and inhibited structural damage of MnO₂, K-V₂C@MnO₂ shows excellent electrochemical performance for aqueous ZIBs. Specifically, it presents the high specific capacity of 408.1 mAh g^-1 at 0.3 A g^-1 and maintains the specific capacity of 119.2 mAh g^-1 at a high current density of 10 A g^-1 in a long-term cycle of up to 10000 cycles. It is superior to almost all reported Mn-based cathodes for ZIBs in the aqueous electrolyte. The superior electrochemical performance suggests that the Mn-based cathode materials designed in this work can be a rational approach to be applied for high-performance ZIBs cathodes.