Authors: Xiuyun Ren, Yanmei Wu, Xijie Chen, Liang Hu, Yu Zhao, Tao Zhang, Bingcheng Ge, Xiaoqi Sun, Xiaoliang Yu
Published: 2025-03-20
DOI: 10.34133/energymatadv.0184
Source: Full article
Battery systems enabling sustainable high energy output at elevated temperatures are highly desirable, especially in high-temperature (HT) environments or hot regions. Sodium metal batteries are attractive next-generation battery technologies with low production costs and high energy densities. The exacerbated detrimental side reactions between the sodium metal anode and the liquid electrolyte at HT, however, reduce sodium plating/stripping reversibility and shorten the cycle life. Ether-based electrolytes are highly compatible with the sodium metal anode, promising good HT electrochemical performances. Nonetheless, the correlation between the molecular structures of ether solvents and HT sodium reversibility has been poorly established because of the complex interfacial reactions. In this study, conventionally used cyclic and linear ethers have been paired with fluorine-rich sodium salt to formulate electrolytes for systematic study. We have revealed that linear ethers outperform cyclic ethers at HT because of their improved thermal stability. Among them, the electrolyte based on diglyme with an appropriate molecular structure delivers the best performance. It strikes a balance in the coordination strength between Na