γ-MnO2 nanorods/graphene composite as efficient cathode for advanced rechargeable aqueous zinc-ion battery

Aqueous Zn//MnObatteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness,high safety,high output voltage,and energy density.However,the MnOcathode suffers from intrinsically poor rate performance and rapid capacity deterioration.Here,we remove the roadblock by compositing MnOnanorods with highly conductive graphene,which remarkably enhances the electrochemical properties of the MnOcathode.Benefiting from the boosted electric conductivity and ion diffusion rate as well as the structural protection of graphene,the Zn//MnO-graphene battery presents an admirable capacity of 301 mAh gat 0.5 A g,corresponding to a high energy density of 411.6 Wh kg.Even at a high current density of 10 A g,a decent capacity of 95.8 mAh gis still obtained,manifesting its excellent rate property.Furthermore,an impressive power density of 15 kW kgis achieved by the Zn//MnO-graphene battery.