Shuttle-effect-free sodium–sulfur batteries derived from a Tröger's base polymer of intrinsic microporosity

Room-temperature sodium–sulfur (RT Na–S) batteries have recently gained attention as next-generation energy storage devices owing to their low cost, the abundance of sodium, and the high theoretical capacity of sulfur. However, the notorious shuttle effect, caused by the dissolution of intermediate polysulfides during cycling, limits the long-term performance of Na–S batteries. In this study, intrinsically microporous Tröger's base based polymer (PIM-EA-TB)-based carbon–sulfur composites are prepared for shuttle-effect-free RT Na–S batteries by utilizing the combination of physical confinement and covalent bonding in a single material. The composites demonstrate excellent electrochemical performance, including a negligible capacity fading over 350 cycles and a high coulombic efficiency of approximately greater than 99%.