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

• Published in: Angewandte Chemie International Edition 2021-04, Vol.60 (18), p.10129-10136
• Main Authors: Zhou, Jiahui, Yang, Yue, Zhang, Yingchao, Duan, Shuaikang, Zhou, Xia, Sun, Wei, Xu, Shengming
• Format: Article
• Language: English
• Subjects: amorphous silica; Bonding strength; Chemical bonds; Containers; electrochemical performance; Energy storage; Flux density; Molecular dynamics; Operating temperature; Polysulfides; room temperature; Silica; Silicon dioxide; Sodium; sodium–sulfur batteries; Sulfur; sulfur electrodes
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202015932

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 gsulfur−1 (nearly 100 % coulomb efficiency and high reversible capacity of 955.8 mAh gsulfur−1 after 1460 cycles). Sulfur as an electrode is loaded into amorphous silica by a facile dipping method. In charge/discharge process, the complex pores of amorphous silica, 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.