Dendrite-free Li metal deposition in all-solid-state lithium sulfur batteries with polymer-in-salt polysiloxane electrolyte

Replacement of solid polymer electrolyte (SPE) to routine liquid electrolyte is highly desirable for high-energy-density lithium sulfur batteries due to its low volatility, high safety and the ability to suppress shuttle effect. Herein, a polymer-in-salt polysiloxane SPE was fabricated with bi-grafted polysiloxane copolymer , lithium bis(trifluoromethanesulfonyl)imide and poly(vinylidene fluoride), which shows higher ionic conductivity (7.8 × 10 -4 S cm -1 at 25 °C). To obtain the satisfactory ionic conductivity and high mechanical property of solid electrolyte simultaneously, cellulose acetate matrix was combined as a rigid substrate to prepare composite polymer electrolyte (CPE) that possesses high ionic conductivity (4.0 × 10 -4 S cm -1 ), enhanced mechanical strength (6.8 MPa), wide electrochemical stability window (4.7 V vs . Li + /Li), and high ion transference number (0.52) at ambient temperature. In addition, the CPE effectively inhibits the growth of lithium dendrites and diffusion of polysulfides . The assembled lithium sulfur battery with CPE exhibits good room-temperature cycling performance at 1C, which indicates that such polymer-in-salt polysiloxane based composite electrolyte membranes can be applied to ambient temperature all-solid-state lithium sulfur batteries .