Lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide as a stabilizing electrolyte additive for improved high voltage application of lithium-ion batteries

Murmann P, Streipert B, Klöpsch R, Ignatiev N, Sartori P, Winter M, Cekic-Laskovic I

Abstract

Lithium-cyclo-difluoromethane-1,1-bis(sulfonyl)imide (LiDMSI) was evaluated as an electrolyte additivein lithium-ion batteries for improved high voltage application. Cycling the cathode at high potentialsleads to an electrochemical oxidation of the salt to form a cathode electrolyte interphase (CEI) layer onthe cathode surface. With the addition of 2 wt.% of LiDMSI to the 1 M LiPF6 in EC:DEC 1:1 (by wt.)electrolyte, the capacity retention and the Coulombic efficiency in LiNi1/3Co1/3Mn1/3O2 / Li-half-cells aswell as LiNi1/3Co1/3Mn1/3O2 / graphite-full-cells was improved. The cycling results point at less overpotentialand resistance at the cathode/electrolyte interface. These improvements are studied by SEM,EIS as well as XPS techniques.