Sulfolane with LiPF6, LiNTf2 and LiBOB - as a non-flammable electrolyte working in a lithium-ion batteries with a LiNiO2 cathode

Abstract

LiNiO2 was examined as cathode materials for the lithium-ion battery, working with non-flammable electrolyte, obtained by dissolution of solid lithium bis(trifluoromethanesulphonyl)imide (LiNTf2), lithium bis(oxalato)borate (LiBOB) and lithium hexafluorophosphate (LiPF6, Fluka) in sulfolane (TMS) with 10% vinylene carbonate (VC). Apart from the electrochemical tests, it was important to set the flash point. The Li/LiNiO2 cells were tested by cyclic voltammetry, galvanostatic charging/discharging. The LiNiO2 cathode showed good cyclability and coulombic efficiency for the electrolyte, which contains 1 M LiPF6 in TMS + 10% VC (195 and 140 mAh g-1 after 20 cycles - C/10). Correspondingly lower capacity was observed for system Li/LiNiO2 in: 1 M LiNTf2 in TMS + 10% VC and 1 M LiBOB in TMS + 10% VC. The LiNiO2(solid) + 1 M LiPF6 + TMS + 10% VC system shows a flash point of ca. 160.