Synergy of Sulfur/Polyacrylonitrile Composite and Gel Polymer Electrolyte Promises Heat-Resistant Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries with high theoretical energy density attract great research attention. Although tremendous efforts have been made, heat tolerance capability of Li-S batteries is a topic rarely touched, although it is essential for practical application. At high temperatures, the dissolution of the polysulfides is aggravated, and the safety issue becomes severe. Herein, by using sulfur/polyacrylonitrile (SPAN) composites as positive electrode materials and a gel polymer membrane with carbonate electrolyte, we successfully realized a Li-S battery with remarkable heat-resistant performance at 50°C and 60°C. The SPAN-positive materials allow the Li-S battery operated in safer carbonate-containing electrolyte. The gel polymer electrolyte enhances the charge transfer, maintains the morphology of Li metal during cycling, and suppresses the migration of the soluble polysulfides, which is also observed when SPAN is used as positive electrode material. This contribution would bring new opportunity to extend the application of lithium batteries at high temperatures. [Display omitted] •A Li-S battery with remarkable heat-resistant performance is obtained•Sulfur/polyacrylonitrile nanocomposites is used as positive electrode materials•Migration of polysulfides is observed during the cycling of the assembled battery•Gel polymer electrolyte is crucial for enhancing the performance at high temperature Electrochemical Energy Conversion; Energy Storage; Materials Characterization