Silver Nanoparticles Guide Uniform Zn Nucleation in the Porous Carbon Skeleton for Dendrite-Free Zinc Metal Anodes

Abstract

Aqueous zinc-based batteries have been proposed as one of the most promising electrical energy-storage systems owing to their unique advantages of low potential, high theoretical capacity, intrinsic safety, low cost and high ionic conductivity. Despite the current progress in the exploration of the cathode (including NiOOH, MnO2, air cathode, etc.) and electrolyte (neutral ZnSO4, Zn(otf)2, “water in salt”, etc.), the practical implementation of zinc-based battery is still largely impeded by the poor cycle life of Zn metal anode due to the formation of dendrites. One attractive strategy is employing three-dimensional (3D) porous metrics as a host for Zn metal. Among the various 3D hosts, carbon-based materials with lightweight properties, chemical stability and low cost are more attractive. However, due to the high electronic conductivity and overpotential of carbon materials to Zn, the Zn is inclined to plate on the surface of carbon skeletons rather than throughout the whole host materials, which limits the effectiveness of the 3D structural design. Here, we prepared Ag nanoparticles anchored on the 3D porous carbon matrix host (Ag-GS/CNT) by freeze-drying and in situ reduction methods. The uniformly distributed Ag nanoparticles with a lower Zn nucleation barrier compared to carbon guide the Zn deposition within the pores of the 3D hosts. The 3D porous carbon host materials with a large active surface can minimize the local current density and suppress dendrite growth. besides, confining the Zn metal within the host effectively restricts the huge volume change, improving the stability of Zn metal anode upon repeated cycles. Both the Zn–air battery and Zn-ion battery based on Ag-GS/CNT//Zn anode display superior electrochemical performance.