Study of Methylene Methanedisulfonate as an Additive for Li-Ion Cells

The effects of Methylene MethaneDiSulfonate (MMDS) as an electrolyte additive for Li-ion cells have been studied using Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 /Li (NMC/Li), Li(Ni 0.8 Co 0.15 Al 0.05 )O 2 )/Li, Coke/Li coin cells and NMC/graphite pouch cells. Storage experiments on all cell types showed that adding MMDS to the electrolyte reduced the rate of parasitic reactions, e.g. electrolyte oxidation, at the Li x MO 2 electrode while it did not affect the rate of reaction of intercalated lithium in coke with electrolyte. NMC/graphite pouch cells with electrolytes containing MMDS produced less gas during formation than cells without MMDS. Impedance tests show MMDS greatly decreases the impedance of the NMC/graphite pouch cells after storage and cycling. Charge discharge cycling experiments confirm that MMDS is a useful electrolyte additive for Li-ion cells.