α-MnO₂@In₂O₃ Nanotubes as Cathode Material for Aqueous Rechargeable Zn-Ion Battery with High Electrochemical Performance

Rechargeable aqueous zinc-manganese batteries have been receiving inclusive attention due to their high energy density, low cost and environmental friendliness. However, the development of manganese dioxide as the cathode for aqueous Zn-ion batteries (ZIBs) is restricted by the speedy capacity attenuation and low rate performance. Herein, a new cathode material α-MnO 2 @In 2 O 3 is proposed. After a uniform coating of In 2 O 3 on the α-MnO 2 nanotubes, the cycling stability and rate performance have all got great improvement due to the enhancement of the electrical conductivity according to the electrochemical kinetical investigation result. α-MnO 2 @In 2 O 3 exhibits a high capacity of 425 mA h g −1 after 100 cycles at 100 mA g −1 , and it can still maintain 115 mA h g −1 at a high current density of 2000 mA g −1 after a long-term cycling of 1300 cycles. Besides, a specific capacity of 75 mA h g −1 is attained at 3000 mA g −1 for 3000 cycles without significant decay. The overall electrochemical performance are superior to most other reported cathode materials so far. This study brings a new coating strategy of using In 2 O 3 to the improvement of the intrinsic poor conductivity of cathode materials other than carbon coating.