Electrostatic Polysulfides Confinement to Inhibit Redox Shuttle Process in the Lithium Sulfur Batteries

Abstract

Cationic polymer can capture polysulfide ions and inhibit polysulfide shuttle effect in lithium sulfur (Li–S) rechargeable batteries, enhancing the Li–S battery cycling performance. The cationic poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino) propyl]urea] quaternized (PQ) with a high density quaternary ammonium cations can trap the lithium polysulfide through the electrostatic attraction between positively charged quaternary ammonium (R4N+) and negatively charged polysulfide (Sx2–). PQ binder based sulfur electrodes deliver much higher capacity and provide better stability than traditional polyvinylidene fluoride (PVDF) binder based electrodes in Li–S cells. A high sulfur loading of 7.5 mg/cm2 is achieved, which delivers a high initial areal capacity of 9.0 mAh/cm2 and stable cycling capacity at around 7.0 mAh/cm2 in the following cycles.