Ultralow Deposition Potential and Antisite-Boosted Diffusivity of Li3Ga2 Anode for All-Solid-State Batteries

Abstract Existing alloy anodes suffer from high redox potentials and sluggish Li atomic kinetics, limiting the energy density and rate capability of all-solid-state lithium batteries (ASSLBs). Herein, we report a well-designed Li3Ga2 alloy anode that simultaneously delivers an ultralow Li deposition potential (0.007 V vs. Li+/Li) and fast Li atomic diffusion kinetics (2.0 × 10–8 cm2 s–1). The high Li atomic diffusivity primarily originates from moderate Li/Ga antisite mixing, stabilizing the anode-solid electrolyte interface and enabling a high critical current density of 24 mA cm–2 in ASSLBs. Coupled with a LiCoO2 cathode, the ASSLB delivers a high initial Coulombic efficiency of 96.5% and an ultralong cycle life of 2000 cycles at room temperature, with a high output voltage of 3.84 V, outperforming state-of-the-art alloy-based counterparts. A practical all-solid-state pouch cell employing the LiNi0.8Co0.1Mn0.1O2 cathode also delivers outstanding cycling stability. This work redefines alloy anode design principles through synergistic optimization of Li deposition potential and Li atomic diffusivity.