Laser-Generated Au nanoparticles as lithophilic sites in self-supported film host for anode-free lithium metal battery

Abstract

Anode-free lithium metal batteries (AFLMBs) are considered to have greater application potential than traditional LMBs because of their higher energy density and safety. Unfortunately, their poor cycling performances originated from the unsatisfactory reversibility of Li plating/stripping remains a big challenge. A rational designed host for lithium deposition is an effective solving strategy. Herein, pure Au nanoparticles (NPs) without any impurities are prepared by a liquid-phase laser irradiation technology to construct and develop a self-supported Au/reduced graphene oxide (Au/rGO) film as lithium deposition host for AFLMBs. The densely and uniformly distributed Au NPs provide abundant lithiophilic sites that significantly reduce the nucleation barrier of lithium. Attributed to the precise regulation of Au sites towards lithium nucleation/growth, dendrites-free anode and improved electrochemical performance are obtained by using the Au/rGO film host. It keeps stable for 30 min of lithiation at 6 mA cm⁻² without dendrite formation. Additionally, the Li||Au/rGO half-cell shows an overpotential close to 0 mV and maintains a Coulombic efficiency exceeding 97 % after 500 cycles at 1 mA cm⁻². Moreover, a symmetric Au/rGO-Li cell can operate for 700 h without short-circuit. When paired with LiFePO₄ (LFP) to assemble a full battery, the Au/rGO-Li achieves 96 % capacity retention rate after 100 cycles. This work not only develops an efficient host for lithium, but also provides a unique strategy to the safety concerns associated with LMBs’ anodes.