Homogeneous Li deposition guided by ultra-thin lithiophilic layer for highly stable anode-free batteries

Abstract

Li-metal batteries (LMBs) are intensively studied to keep up with the growing demand for sustainable and high-capacity energy storage devices. However, the practical implementation of LMBs is still challenging owing to the catastrophic side effects associated with the growth of dendritic Li and inferior Coulombic efficiency. To enhance the long-term electrochemical stability and high-rate performance of LMBs, it is crucial to control the morphology of Li deposition over the current collectors. Herein, we propose surface-modified current collectors to investigate how a lithiatable layer affects the morphology of Li deposition and thus contributes to the stable electrochemical performance of LMBs at high current densities. The lithiatable layer improves the electrolyte wetting ability, which efficiently diminishes the interfacial resistance between electrode and electrolyte. Moreover, the lithiatable layer induces homogeneous Li nucleation, consequently leading to the uniform Li deposition over the surface of current collectors. Due to these synergistic effects, the anode-free cells with surface-modified current collectors have achieved excellent cycle stability in comparison to that with conventional Cu current collector.