Minimizing Polysulfide Shuttles in Lithium Sulfur Batteries by Introducing Immobile Lithium Ions into Carbon–Sulfur Nanocomposites

Abstract

AbstractA facile synthesis of a carbon–sulfur nanocomposite, of which the capacity retention ratio is substantially enhanced by almost 100 %, is presented for polysulfide shuttle reduction in lithium sulfur batteries through the introduction of immobile lithium‐ion sites into the composite. A commercial Nafion ionomer, which can reduce thiosulfate sodium to sulfur in situ, owing to its acidity, provides immobile lithium ions after lithium exchange in the nanocomposite to attract the negatively charged polysulfide species for reduction during discharge. The capacity decay of the second cycle discharge, which is about 25 % of the value for a conventional carbon–sulfur composite, is reduced to about 3 % by introducing Nafion into the nanocomposite, and the capacity retention of this novel carbon–Nafion–sulfur nanocomposite is improved by more than 100 % during long‐term battery operation.