Lithium phosphide/lithium chloride coating on lithium for advanced lithium metal anode

Abstract

Lithium metal has been regarded as an ideal anode material for high-energy-density batteries. However, its high chemical reactivity, virtually infinite volume change and dendrite growth greatly reduce coulombic efficiency and increase potential safety hazards, thereby limiting its practical performance. Here, Li₃P/LiCl-coated Li was successfully prepared by a simple reaction between PCl₃ and Li at room temperature. Li₃P, as a Li-ion conductor, reduces interface impedance and improves the electrochemical kinetics. LiCl, as the minor phase, enhances Li diffusion at the interfaces and reinforces the Li metal protection together with Li₃P, suppressing the formation of Li dendrites. Thus, cycle stability and rate capability are greatly improved, as demonstrated both in symmetric cells and in the Li//LiCoO₂ and Li//S full cells.