3D confined zinc plating/stripping with high discharge depth and excellent high-rate reversibility

Abstract

Aqueous Zn-based batteries have been considered as a promising energy storage device due to their high safety, low cost, nontoxicity, and high energy density. However, the poor cycle life-span and limited utilization of zinc anodes due to dendrite growth restrict the practical application of such batteries. Herein, we report the preparation of a Zn/carbon nanotube (Zn/CNT) foam, where zinc plating/stripping is confined in a robust 3D interconnected CNT network. When tested in symmetric cells, the Zn/CNT foam shows excellent cycling stability at high depth of discharge (DOD_Zn, e.g. 100% capacity retention at DOD_Zn < 81% after hundreds of cycles) and high current densities with low overpotentials and without dendrite formation, outperforming zinc foils. As a result, aqueous Zn//MnO₂ batteries assembled using Zn/CNT foam as the anode exhibit high-rate and long-term cycling performance, resulting in a high energy density of 169 W h kg⁻¹ (1C) and a high power density of 3.1 kW kg⁻¹ (30C). This 3D confinement strategy for zinc plating and stripping could help the development of high-energy-density and high-power density zinc-based batteries.