Superior-Performance Aqueous Zinc-Ion Batteries Based on the In Situ Growth of MnO2 Nanosheets on V2CTX MXene.

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 V2CTX MXene surface, is elaborately designed and synthesized by metal-cation intercalation and following in situ 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.