Interface reconstruction via lithium thermal reduction to realize a long life all-solid-state battery

Lithium garnet solid-state electrolytes (SSEs) with high ionic conductivity and high electrochemical stability are promising in the new generation batteries, but the poor interface stability restricts their development. Here, a compatible Li/garnet interface is constructed in-situ through lithium thermal reduction (LTR), in which a Li2O interlayer with electronic insulation blocks the transfer of electrons to the electrolyte, and an oxygen vacancy (OV) interlayer with rapid ion diffusion kinetics uniforms lithium-ion flux at the interface. Benefiting from the dual-function of the interface, the reconstructed symmetrical lithium cell is cycled stably for 2500 h at 0.3 mA cm–2, with a constant voltage polarization about 35 mV. The assembled all-solid-state lithium metal batteries (SSLMBs) exhibit a capacity retention of 93% after 1250 cycles at 1 C rate and 30 °C. This work provides an effective and convenient method for the integration of lithium metal anode in the garnet solid-state batteries