Zwitterionic osmolyte-inspired additives as scavengers and low temperature performance enhancers for lithium ion batteries

Abstract

Zwitterionic lithium-silica sulfobetaine silane (Li-SiSB) is fabricated and used as an additive together with hydroxyl–terminated poly(dimethylsiloxane) (PDMS-HT) for use as low temperature additives in lithium ion batteries (LIB). The additives dissolved in 1 M LiPF6 (ethylene carbonate/dimethyl carbonate = 1:1). The electrolyte containing Li-SiSB and PDMS-HT shows higher ionic conductivity (1.54 × 10-3 Scm−1 at −20 °C). Full cells show enhanced specific capacity at higher C-rates in the presents of additives due to anti–freezing and enhanced ionic conductivity. The also enhance early, stable and dense SEI which in turn leads to improved cycling stability. These results merit the use of both Li-SiSB and PDMS-HT as electrolyte additives for improved low temperature performance in lithium-ion batteries.