Mechanochemical reactions of MnO2 and graphite nanosheets as a durable zinc ion battery cathode

Manganese dioxide has been recognized as the ideal cathode for the aqueous zinc ion batteries (ZIBs). Nevertheless, the poor conductivity and infinite relative volume changes limit its further practical applications. Herein, we developed a promising cathode design by ball milling of electrolytic manganese dioxide (MnO2) in the presence of graphite nanosheets. MnO2/graphite hybrids with the increase of contact surface and interfacial interaction are beneficial to construct an interfacial 3D conductive network and improve the inherent stability, which achieve the minimum volume change. As expected, the rate and cycling performance of MnO2/graphite hybrids (230 mAh g−1 at 0.1 A g−1, 80 mAh g−1 at 1 A g−1, 80.8% after 1000 cycles at 1 A g−1) are better than that of MnO2 (113 mAh g−1 at 0.1 A g−1, 24 mAh g−1 at 1 A g−1, 51.2% after 1000 cycles at 1.0 A g−1). The reduced volume change during charging/discharging can be observed via in situ optical observations. Furthermore, the Zn ion battery delivers higher energy density of 247 Wh kg−1 at 0.27 kW kg−1 and higher power density of 11.78 kW kg−1 at 78 Wh kg−1. Our work demonstrates the successful and large-scale conversion of industrial electrolytic manganese dioxide into a high-performance cathode of ZIBs.