All-solid-state lithium secondary batteries with metal-sulfide-coated LiCoO2 prepared by thermal decomposition of dithiocarbamato complexes

LiCoO2 particles were coated with cobalt and nickel sulfides by thermal decomposition of their respective diethyldithiocarbamato complexes. All-solid-state lithium secondary batteries were fabricated using the coated LiCoO2 positive electrode and a Li2S–P2S5 solid electrolyte. The coatings reduced the interfacial resistance between LiCoO2 and the Li2S–P2S5 solid electrolyte of the all-solid-state batteries after the first charge, resulting in an improved cell performance. The all-solid-state cell with NiS-coated LiCoO2 was charged and discharged at a high rate of 10 C. The coatings reduced deterioration of the interface between LiCoO2 and the Li2S–P2S5 solid electrolyte, indicating that they function as an effective buffer layer at the interface.