Sulfur in Amorphous Silica for an Advanced Room‐Temperature Sodium–Sulfur Battery

The room‐temperature (RT) Na/S battery is a promising energy storage system owing to suitable operating temperature, high theoretical energy density, and low cost. However, it has a poor cycle life and low reversible capacity. In this work, we report a long‐life RT‐Na/S battery with amorphous porous silica as a sulfur host. The sulfur is loaded into amorphous silica by a dipping method; the optimal sulfur loading is up to 73.48 wt %. Molecular dynamics simulation and first‐principles calculations suggest that the complex pores, acting as micro‐containers and the formation of Na‐O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle. This would give rise to effectively avoiding the loss of active sulfur, corresponding to a superior capacity and an excellent cyclability even at 10 A g sulfur −1 (nearly 100 % coulomb efficiency and high reversible capacity of 955.8 mAh g sulfur −1 after 1460 cycles).