High rate capabilities of all-solid-state lithium secondary batteries using Li4Ti5O12-coated LiNi0.8Co0.15Al0.05O2 and a sulfide-based solid electrolyte

► Rate capability of LiNi0.8Co0.15Al0.05O2 in solid-state cells was investigated with 70Li2S-30P2S5 glass-ceramics as a sulfide solid electrolyte. ► It showed higher rate capability than LiCoO2; discharge capacity observed at a current density of 10 mAh cm−2 was ca. 70 mAh g−1. ► Surface coating with Li4Ti5O12 onto the LiNi0.8Co0.15Al0.05O2 particles further improved the high-rate performance to give ca. 110 mAh g−1.