Energy-dense aqueous Zn//MnO2 rechargeable battery constructed on dual three-dimensional conductive skeletons

Abstract

Enhancing the energy density of aqueous rechargeable zinc-based batteries is critical for boosting their application in a variety of practical scenarios. Herein we demonstrate a strategy to improve specific energies of Zn//MnO2 batteries in mild electrolyte via utilizing three-dimensional (3D) current collectors for both the anode and cathode. By electrodepositing limited amounts of Zn on surface-alloyed Ag mesh and coupling it with MnO2 cathode electrodeposited on carbon cloth with no binder, the resultant batteries exhibit specific energy up to 253 and 196 Wh/kg (based on total mass of active materials) at negative-to-positive electrode capacity (N/P) ratios of 1:1 and 2:1. By elevating the working temperature to 35 °C, the specific energy and life span of the battery with N/P = 2 can be further increased to 216 Wh/kg and >225 cycles, respectively. The key to achieving a high specific energy relies primarily on the great reversibility of the Zn anode, which is conferred by the 3D Ag mesh.