Realizing fast plating/stripping of high-performance Zn metal anode with a low Zn loading

Abstract

Zn metal batteries and capacitors (ZMBs/ZMCs) are gaining significant attention due to their low cost, high safety, and high theoretical capacity. However, the low utilization of Zn metal decreases the coulombic efficiency. Here, we present a novel approach to enhance the conductivity of host materials by utilizing a 3D conductive structural network of copper mesh. The 3D copper mesh serves as a high-conductive matrix and additionally coating it with Zn serves as a Zn source. Finally, a flexible reduced graphene oxide (rGO) was deposited on the Zn-coated copper mesh as an anode protective layer. The conductive copper mesh renders a fast plating/stripping of Zn and enables more contact of Zn with the electrolyte. The flexible rGO film deposited on Zn-coated copper mesh alleviates the local charge accumulation and inhibits corrosion. As a result, the Zn-coated copper mesh anode modified with rGO (RCZ) exhibited a longer lifespan of 200 h than the Zn-coated planar copper foil anode which cycled only for 30 h. The RCZ||AC full capacitor obtained high capacity retention of 97.9% after 9000 times cycling. The RCZ anode integrates the merits of 3D structure matrix and rGO realizing a dual-functionalized Zn metal anode. The conductive matrix strategy sheds light on other metal batteries.