Silicon/graphite composite host for tuned lithiophilicity in Li metal anodes

Abstract

Lithium metal anodes (LMAs) are promising for next-generation high energy density (ED) batteries due to their exceptional theoretical capacity (3860 mAh g⁻¹) and low electrochemical potential (−3.04 V vs. the standard hydrogen electrode). However, several issues including lithium (Li) dendrite growth formation, poor coulombic efficiency (CE), and unstable solid electrolyte interphase (SEI) formation hinder their practical performance. Here, we developed a LMA current collector (CC) prepared with a silicon (Si)/graphite (Gr) composite layer on copper (Cu) foil. The lithiophilicity of the CC enabled improved stability during extended Li plating/stripping. In full-cell testing the Li/Cu–Si/Gr anode versus sulfur and lithium nickel manganese cobalt oxide (NMC811), delivered average CE values of 95% and 98.82% during 150 charge/discharge cycles at 0.2C, respectively. Rate capability tests revealed that Li/Cu–Si/Gr enabled high areal capacities of 0.837 mAh cm⁻²versus sulfur and 0.607 mAh cm⁻²versus NMC at a high C-rate of 1C. This work highlights the possibility of harnessing conventional Li-ion battery anode materials as surface-modifying lithiophilic agents for LMAs.