A comparison study of MnO 2 and Mn 2 O 3 as zinc-ion battery cathodes: an experimental and computational investigation.

The high specific capacity, low cost and environmental friendliness make manganese dioxide materials promising cathode materials for zinc-ion batteries (ZIBs). In order to understand the difference between the electrochemical behavior of manganese dioxide materials with different valence states, i.e. , Mn(iii) and Mn(iv), we investigated and compared the electrochemical properties of pure MnO 2 and Mn 2 O 3 as ZIB cathodes via a combined experimental and computational approach. The MnO 2 electrode showed a higher discharging capacity (270.4 mA h g -1 at 0.1 A g -1 ) and a superior rate performance (125.7 mA h g -1 at 3 A g -1 ) than the Mn 2 O 3 electrode (188.2 mA h g -1 at 0.1 A g -1 and 87 mA h g -1 at 3 A g -1 , respectively). The superior performance of the MnO 2 electrode was ascribed to its higher specific surface area, higher electronic conductivity and lower diffusion barrier of Zn 2+ compared to the Mn 2 O 3 electrode. This study provides a detailed picture of the diversity of manganese dioxide electrodes as ZIB cathodes.