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

Abstract

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.