Suppressing Dendrite Formation through Au-Driven Interfacial Engineering for Solid-State Lithium-Metal Batteries

초록

This study investigates the implementation of an Au nanolayer coating on Li-metal anodes. We explore the efficacy of a thin and conductive Au layer, sputtered onto Li metal, in improving the interfacial resistance and operational stability when combined with a poly(ethylene oxide)-based solid-state polymer electrolyte (SPE). We demonstrate that the Au coating not only mitigates overpotential and enhances the coulombic efficiency (CE) but also prevents the formation of undesirable lithium dendrites during cycling. Electrochemical measurements, including impedance spectroscopy (EIS), and synchrotron tomography (ST), reveal that the Au layer promotes homogeneous Li plating/stripping. In addition, density functional theory (DFT) and nudged elastic band (NEB) calculations show that Li adatom diffusion on Au(111) has a much lower energy barrier than on Li(100), enabling faster surface mobility and uniform Li deposition. The enhanced interfacial stability is further supported by the extended cyclability of up to 1000 cycles corresponding to nearly 1 year and 11 months of continuous operation with minimal capacity fade, observed in LiFePO4||SPE||Li full cells employing Au-coated anodes. Surface analysis confirms the robustness of the solid-electrolyte interphase layer and the protective role of the Au layer against oxidative degradation and dendritic growth, improving the safety and cyclability of solid-state Li-metal batteries.

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