Dendrite-Free All-Solid-State Lithium-Metal Battery by In-Situ Phase Transformation of Soft Carbon-Li3n Interface Layer

The rapid growth of lithium dendrites has seriously hindered the development and practical application of high-energy-density all-solid-state lithium metal batteries (ASSLMBs). Herein, a soft carbon (SC)-Li3N mixed ionic and electronic conductive interface layer is designed, for which the in-situ lithiation reaction not only lithiated SC into LiC6 with good electronic/ionic conductivity, but also successfully transformed the mixed-phase Li3N into pure-phase β-Li3N with high ionic conductivity/ion diffusion coefficient and stability to lithium metal. This promotes the rapid migration of Li+ at the interface layer, induces the uniform deposition of lithium metal inside the interface layer, effectively suppresses the growth of lithium dendrites, and significantly improves the electrochemical performance of ASSLMB. LZO@LCO/LPSCl/SC-Li3N/Li ASSLMB achieves high current density (7.5 mA cm-2), ultra-high areal capacity (15 mAh cm-2, corresponding to LZO@LCO mass loadings of 114.14 mg cm-2), and ultra-long cycle life (6000 cycles). Therefore, the introduction of SC-Li3N mixed conducting interface layer can greatly improve the interfacial stability between solid-state electrolyte (SSE)/lithium metal anode and enable dendrite-free ASSLMBs.