High-voltage all-solid-state lithium batteries with Li3InCl6 electrolyte and LiNbO3 coated lithium-rich manganese oxide cathode

The all-solid-state lithium battery (ASSLB) with lithium-rich manganese oxide (LRMO) cathode material is one of the strongest competitors for the next generation energy-storage device with high energy density. However, due to the serious interfacial reaction between LRMO and halide solid-state electrolyte (SSE), its electrochemical performance cannot meet the practical demand. In this work, in-situ electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) tests and high resolution transmission electron microscope (HR-TEM) are carried out to clarify the interfacial reaction mechanism between LRMO and Li3InCl6 (LIC). The active oxygen released from LRMO and phase transition of LRMO are confirmed to seriously deteriorate the LRMO/LIC interface. To solve the above problems, a uniform LiNbO3 coating is introduced to alleviate the interfacial side reaction and phase transition of LRMO. With moderate coating amount (1.5 wt%, ∼10 nm thick), the LNO@LRMO cathode shows an initial discharge capacity of 185 mA h g − 1 with 67% capacity retention after 100 cycles in halide-based ASSLB, which greatly exceeds that of bare LRMO cathode under voltage range of 2.3–4.8 V. This work provides a new perspective for improving the performance of LRMO in halide-based ASSLBs to achieve high energy density.