Deciphering the Effect of Electrical Conductivity of Hosts on Lithium Deposition in Composite Lithium Metal Anodes

Lithium metal anodes demonstrate inferior cycling stability due to uncontrolled Li deposition and large volume fluctuation. Composite Li metal anodes with a 3D host show stable Li deposition. Nevertheless, the advantages of a host are achieved by the joint effect of various parameters. The effect of a single parameter of a host on Li deposition is veiled, hindering the rational design of a host. Herein, a decoupling method is demonstrated to decipher the effect of host electrical conductivity, a vital parameter, on the behaviors of Li deposition. In order to decouple the effect of host electrical conductivity, a conductive host is modulated by in situ formation of a polymer coating while maintaining the other parameters unchanged. The host electrical conductivity dictates the distribution of electric potential in the vicinity of the host, then the transport of Li ions, and finally behaviors of Li deposition. The cycling performance of the host with high electrical conductivity outperforms that with low electrical conductivity. This work initiates a decoupling methodology to probe the effect of host properties on the behaviors of Li deposition, and provides guidance for the rational design of Li metal anode host materials.