Physically Coated Gold Film on Copper Mesh Electrode for Anode-Free Batteries

The growing demand for electric vehicles is driving the development of next-generation batteries with higher energy densities, surpassing the limitations of conventional graphite anodes. Lithium metal-based anodes present promising solutions due to their high theoretical capacity (3860 mAh g^–1) and the lowest electrochemical potential (−3.04 V versus standard hydrogen electrodes). However, practical application is hindered by challenges, such as dendrite growth, volume expansion, and unstable solid electrolyte interphase (SEI) formation. This study introduces a straightforward calendering coating process to apply a lithiophilic gold (Au) layer on a copper current collector (i.e., Cu mesh), utilizing established electrode manufacturing techniques. The Au-coated Cu mesh electrode significantly reduces the lithium nucleation overpotential, promoting uniform lithium deposition and growth. Electrochemical characterization revealed that the Au-coated Cu mesh achieved a high coulombic efficiency (CE) of 93.76% after 50 cycles in half-cells with 1 mAh cm^–2 lithium plating and 91.58% after 50 cycles with 2 mAh cm^–2 lithium plating. The findings demonstrate that the simple calendering Au coating method effectively mitigates volume expansion, promotes stable SEI formation, and suppresses lithium dendrite growth, offering a scalable approach to advancing anode-free lithium metal battery technology. This study provides valuable insights for designing process-compatible protective layers for anode-free lithium metal batteries.