A robust solid electrolyte interphase enabled by solvate ionic liquid for high-performance sulfide-based all-solid-state lithium metal batteries

All-solid-state lithium metal batteries (ASSLMBs) that incorporate solid electrolyte (SE) and lithium metal anode suggest considerable potential in addressing the security concerns and energy density limitation of conventional lithium-ion batteries (LIBs). However, the practical application of ASSLMBs is always restricted by the interfacial instability of lithium metal anode/electrolyte and inevitable lithium dendrites propagation in SE. Herein, a solvate ionic liquid is adopted to modify the interface stability of lithium metal anode/electrolyte and inhibit the growth of lithium dendrites via an in-situ formation of a robust solid electrolyte interphase (SEI) on the surface of lithium metal anode. Consequently, the ASSLMBs assembled with Li6PS5Cl (LPSCl) electrolyte, lithium metal anode that protected by robust SEI layer, and LiNbO3@NCM622 cathode exhibit high initial capacity of 126.5 mAh·g−1 and improved cycling stability with a capacity retention of 80.3% over 60 cycles at 0.1 C. This work helps to provide a facile route for the design of robust SEI in the application of ASSLMBs.