Improvement of lithium-ion battery performance at low temperature by adopting polydimethylsiloxane-based electrolyte additives

Abstract Three kinds of polydimethylsiloxane (PDMS)-based grafted and ungrafted copolymers such as poly[dimethylsiloxane- co -(siloxane- g -acrylate)] (PDMS-A), poly(dimethylsiloxane- co -phenylsiloxane) (PDMS-P), and poly[dimethylsiloxane- co -(siloxane- g -ethylene oxide)] (PDMS-EO) are used as additives to standard liquid electrolyte solutions to enhance the lithium-ion battery performance at low temperatures. Liquid electrolyte solutions with PDMS-based additives are electrochemically stable under 5.0 V and have adequate ionic conductivities of 10 −4  S cm −1 at -20 °C. Particularly, liquid electrolytes with PDMS-P and PDMS-EO exhibit higher ionic conductivities of around 5 × 10 −4  S cm −1 at -20 °C, indicating a specific resisting property against the freezing of the liquid electrolyte components. As a result, the addition of PDMS-based additives to liquid electrolytes improves the capacity retention ratio and rate-capability of lithium-ion batteries at low temperatures.