A Stable Quasi‐Solid‐State Sodium–Sulfur Battery

Ambient‐temperature sodium–sulfur (Na–S) batteries are considered a promising energy storage system due to their high theoretical energy density and low costs. However, great challenges remain in achieving a high rechargeable capacity and long cycle life. Herein we report a stable quasi‐solid‐state Na‐S battery enabled by a poly(S‐pentaerythritol tetraacrylate (PETEA))‐based cathode and a (PETEA‐tris[2‐(acryloyloxy)ethyl] isocyanurate (THEICTA))‐based gel polymer electrolyte. The polymeric sulfur electrode strongly anchors sulfur through chemical binding and inhibits the shuttle effect. Meanwhile, the in situ formed polymer electrolyte with high ionic conductivity and enhanced safety successfully stabilizes the Na anode/electrolyte interface, and simultaneously immobilizes soluble Na polysulfides. The as‐developed quasi‐solid‐state Na‐S cells exhibit a high reversible capacity of 877 mA h g−1 at 0.1 C and an extended cycling stability. Energy storage: A stable quasi‐solid‐state Na–S battery has been obtained using a poly(S‐pentaerythritol tetraacrylate (PETEA)) cathode and a (PETEA‐tris[2‐(acryloyloxy)ethyl] isocyanurate (THEICTA)) gel polymer electrolyte. The electrode strongly anchors sulfur by chemical binding, meanwhile the polymer electrolyte with high ionic conductivity and stable Na/electrolyte interface effectively suppresses the shuttle of polysulfides.