An in situ fabricated multifunctional gel electrolyte for lithium–sulfur batteries

Abstract

Despite the high-energy lithium–sulfur (Li–S) batteries being a promising secondary batteries system, their commercialization is seriously hindered by the polysulfides shuttle, unstable lithium anode and safety hazards in the traditional liquid electrolytes. Herein, a multifunctional gel polymer electrolyte (ANPD-GPE) is fabricated, which is composed of Nafion-coated Al2O3 nanofibers and in-situ polymerized 1,3-dioxolane (DOL). Lewis-acidic Al2O3 has a strong effect on the Lewis base of bis(trifluoromethanesulphony)imide anions, facilitating the transport of Li+ and resulting in a reduced Li+ concentration gradient. In addition, the replacement of a flammable polyolefin separator by the inorganic Al2O3 robust nanofibers skeleton can effectively promote the structural and thermal stability of electrolytes. The introduction of Nafion effectively inhibits the shuttle effect vis polymerization of DOL and the electrostatic repulsion of its anions. The in-situ polymerized elastic poly-DOL (PDOL) can stabilize the lithium anode because of its accommodation for the fluctuating interface during cycling. Consequently, Li–S cells with ANPD-GPE present improved electrochemical performance in terms of cathode cyclability and lithium anode stability.