Improvement of stability and solid-state battery performances of annealed 70Li2S–30P2S5 electrolytes by additives

The replacement of liquid electrolyte with solid electrolyte can significantly improve the safety and power/energy density of lithium batteries. 70Li2S–30P2S5 is one of the most promising solid electrolytes with high conductivity for solid–state batteries. In this work, the ionic conductivity and stability toward moisture and lithium metal of 70Li2S–30P2S5 were enhanced by introducing the different amounts of Li2O additives. 65Li2S–30P2S5–1%Li2O delivered the highest conductivity, while 65Li2S–30P2S5–5%Li2O showed the best moisture stability and improved lithium compatibility. Solid-state batteries using 65Li2S–30P2S5–5%Li2O electrolyte and high-voltage LiNi0.6Mn0.2Co0.2O2 cathode exhibited low initial discharge capacity (100 mAh·g−1) and Coulombic efficiency (69%). Li3InCl6 electrolytes were introduced both in the cathode mixture to replace sulfide electrolyte and in the interface layer to improve the cathode compatibility for the solid-state batteries, showing enhanced discharge capacity (175 mAh·g−1) and improved initial Coulombic efficiency (86%). Moreover, it also exhibited good performance at − 20 °C.