Permselective Graphene Oxide Membrane for Highly Stable and Anti-Self-Discharge Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries hold great promise for serving as next generation high energy density batteries. However, the shuttle of polysulfide induces rapid capacity degradation and poor cycling stability of lithium–sulfur cells. Herein, we proposed a unique lithium–sulfur battery configuration with an ultrathin graphene oxide (GO) membrane for high stability. The oxygen electronegative atoms modified GO into a polar plane, and the carboxyl groups acted as ion-hopping sites of positively charged species (Li⁺) and rejected the transportation of negatively charged species (S_<i>n</i>^2–) due to the electrostatic interactions. Such electrostatic repulsion and physical inhibition largely decreased the transference of polysulfides across the GO membrane in the lithium–sulfur system. Consequently, the GO membrane with highly tunable functionalization properties, high mechanical strength, low electric conductivity, and facile fabrication procedure is an effective permselective separator system in lithium–sulfur batteries. By the incorporation of a permselective GO membrane, the cyclic capacity decay rate is also reduced from 0.49 to 0.23%/cycle. As the GO membrane blocks the diffusion of polysulfides through the membrane, it is also with advantages of anti-self-discharge properties