A Nafion protective layer for stabilizing lithium metal anodes in working lithium–sulfur batteries

Abstract Lithium–sulfur batteries are promising next‐generation energy storage devices due to their ultrahigh theoretical energy density. However, the parasitic reactions between lithium polysulfides and lithium metal anodes render lithium anodes extremely unstable during cycling and result in limited lifespan of working lithium–sulfur batteries. Herein, a Nafion protective layer is fabricated for stabilizing lithium metal anodes in working lithium–sulfur batteries. The Nafion protective layer eliminates the parasitic reactions between lithium polysulfides and lithium metal anodes. Accordingly, the cycling lifespan of lithium–sulfur batteries is doubled to 92 cycles with the Nafion protective layer using high‐sulfur‐loading cathodes and ultrathin lithium metal anodes. This study describes an effective Nafion protective layer for stabilizing lithium metal anodes and provides a possible avenue for further protective layer design for achieving long‐cycling practical lithium–sulfur batteries.