Cobalt-Doped Layered MnO₂ Thin Film Electrochemically Grown on Nitrogen-Doped Carbon Cloth for Aqueous Zinc-Ion Batteries

The layered manganese dioxide (δ-type MnO2) film electrodeposited on carbon cloth (CC) functioned as a cathode in aqueous zinc-ion batteries. Battery performance was notably improved by doping MnO2 layers with cobalt and the CC surface with nitrogen. The δ-MnO2 interlayer accommodated Zn2+ ions in the as-deposited state and thus could act as an intercalation host during the discharging process. The Co-doped MnO2 film on the nitrogen-doped CC delivered a discharge capacity as high as 280 mA h g–1 at a specific current of 1.2 A g–1 for 600 charge/discharge cycles, while the discharge capacity did not exceed 30 mA h g–1 even at a specific current as high as 10.5 A g–1. These values are superior to those observed in the absence of doping, demonstrating the positive impact of Co- and N-doping into the MnO2 layers and the CC substrate on the cycling stability and rate capability.