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Ternary and Quaternary Electrolyte Additive Mixtures for Li-Ion Cells That Promote Long Lifetime, High Discharge Rate and Better Safety

2014; Institute of Physics; Volume: 161; Issue: 9 Linguagem: Inglês

10.1149/2.0541409jes

1945-7111

Lin Ma, D. Y. Wang, Laura E. Downie, Jianye Xia, K. J. Nelson, Nidhi Sinha, J. R. Dahn,

Advancements in Battery Materials

Combinations of vinylene carbonate (VC), a sulfur-containing additive like methylene methane disulfonate (MMDS), and tris(-trimethyl-silyl)-phosphite (TTSPi) and/or tris(-trimethyl-silyl)- phosphate (TTSP) used as electrolyte additives in Li(Ni1/3Mn1/3Co1/3)O2 (NMC111)/graphite Li-ion cells are shown to impart exceptional properties to those cells. These ternary or quaternary additive mixtures: apparently reduce parasitic reactions, such as electrolyte decomposition, at the positive electrode above 4.1 V compared to VC alone; increase the thermal stability of the charged graphite electrode at elevated temperature; improve coulombic efficiency and also reduce impedance of the cells. These factors all suggest longer lived, safer, higher power Li-ion cells with better tolerance to high voltages which will improve energy density.