Optimizing Electrolyte Additive Loadings in NMC532/Graphite Cells: Vinylene Carbonate and Ethylene Sulfate

A matrix of LiNi 0.5 Mn 0.3 Co 0.2 O 2 /graphite cells filled with 1.33 molal LiPF 6 in EC:EMC:DMC (ethylene carbonate: ethyl methyl dimethyl carbonate) (25:5:70 by volume) electrolyte and different weight percentages vinylene carbonate (VC) ethylene sulfate (DTD) additives underwent prolonged charge-discharge cycling at 20 °C 40 °C. The volume gas produced during formation cycle testing was measured. impedance spectra the before after After testing, extracted for study nuclear magnetic resonance spectroscopy (NMR) chromatography/mass (GC-MS) to determine what changes composition had occurred. Some their negative electrodes studied scanning micro-X-ray fluorescence quantify amount transition metals that transferred from positive electrode testing. Cells containing 1% VC or 2% an additional DTD best capacity retention lowest growth. NMR GC-MS suggest these additive combinations promote increased salt consumption which may represent a source lithium replenish inventory. Only small (0.03% less) originating active material found on Most over 1500 cycles both conditions.