Enhanced Cyclic Stability of Sulfur Electrode by a Li‐Nafion‐Supported Encapsulated Configuration

Abstract

Lithium–sulfur batteries are deemed to have the opportunity to replace lithium‐ion batteries because of their high energy density. Nonetheless, the shuttling of soluble long‐chain polysulfides severely deteriorates the cyclic performances of the batteries. Herein, an encapsulated sulfur electrode to tackle the shuttle effect is designed. This high‐performance electrode is fabricated by encapsulating the active sulfur inside a sealing configuration composed of lithiated Nafion (Li‐Nafion), carbon black (BP2000), and a binder of polytetrafluoroethylene. The dense surface of the encapsulated configuration can physically obstruct the mobility of soluble polysulfides. Meanwhile, the sulfonic acid groups fixed on the Li‐Nafion backbone provide a robust electrostatic repulsion to inhibit the negatively charged polysulfides from migrating into the electrolyte. Therefore, the encapsulated sulfur electrode delivers 522.6 mAh g−1 at the 600th cycle with a retention of 80.36%, exhibiting a more competitive cyclic stability than the pristine sulfur electrode.