Preparation and electrochemical properties of α-MnO2/rGO-PPy composite as cathode material for zinc-ion battery

Aqueous zinc-ion secondary batteries (ZIBs), especially Zn-MnO2 aqueous battery, have been stirred up widespread concern due to the high capacity, environmental friendliness, and reliable safety performance. However, low conductivity of MnO2 and the dissolution of manganese will hinder its application as cathode material for ZIBs with high rate performance and excellent cycle stability. In this work, α-MnO2/rGO nanowires were coated with conductive polypyrrole via in situ self-polymerization. As used as cathode material for ZIBs, α-MnO2/rGO-PPy shows the reversible capacity of 248.8 mAh g−1 at 0.5 A g−1 and still achieves 213.8 mAh g−1 after 100 cycles, demonstrating much enhanced performance compared with α-MnO2/rGO and α-MnO2. The excellent performances should be due to the polypyrrole coating and incorporation of reduced graphene oxide, which not only alleviate the dissolution of Mn but also improve the conductivity of the whole electrode.