In-situ prelithiation of electrolyte-free silicon anode for sulfide all-solid-state batteries

All-solid-state batteries (ASSBs) based on silicon (Si) anodes offer high energy density and safety, which are considered promising next-generation energy-storage systems. However, the large initial capacity loss of Si anodes greatly limits the practical capacity and rate performance of ASSBs. Herein, through the unique in-situ prelithiation of electrolyte-free Si anodes by using ultra-thin lithium (Li) foil, the Li6PS5Cl electrolyte-based ASSBs achieve significantly improved initial Coulombic efficiencies (ICEs). The results of three-electrode ASSBs confirm that the in-situ prelithiation strategy effectively improves the reversible delithiation capacity and solid-state Li kinetics of electrolyte-free Si anode. The full cells utilizing prelithiated Si anode and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode exhibit a remarkable energy density of 402 Wh kg−1 (based on the total mass of cathode and anode) at 0.1 C and achieve a wide operating temperature range between −30 and 50 °C. In addition, the bi-polar stacking cell with high-loading NCM811 cathode achieves a high cut-off voltage of 8.7 V and works stable for over 50 cycles. This practical prelithiation method presents substantial advantages to promote the development of ASSBs based on Si anodes with high ICEs and fast Li kinetics, offering a pathway to realize solid-state storages with high rates and high energy densities.