High-Sulfur-Loading Gel Cathode Employing a Self-Supporting Composite Matrix for Lithium-Polysulfide Batteries

Abstract

Aimed at the application drawbacks of lithium-polysulfide semiflow battery involved with low utilization of active material and inevitable shuttle effect, a self-supporting porous substrate characterized by high porosity and outstanding conductivity is developed in this study, which consists of cotton-derived nanofiber and graphene wrapped on the nanofiber. Then a gelable polymer poly-(vinylidenefluoride-hexafluoropropylene) is further integrated into the porous substrate for fabricating novel PS gel cathode. The as-prepared composite matrix possesses strong PS adsorption/loading ability by gelation as well as favorable electron/ion transport pathway, which not only provides effective restriction toward PS migration and shuttle, but also actualizes rapid redox conversion of the localized active species. Consequently, the resultant PS gel cathode demonstrates high reversible capacity, and excellent cycle and rate capability even at a high sulfur loading up to 9.0 mg cm⁻².