A safe and non-flammable sodium metal battery based on an ionic liquid electrolyte

• DOI: 10.1038/s41467-019-11102-2
• Publication Date: 2019-07-24T13:07:35Z
• Authors: Hao Sun; Guanzhou Zhu; Xintong Xu; Meng Liao; Yuan-Yao Li; Michael Angell; Meng Gu; Yuanmin Zhu; Wei Hsuan Hung; Jiachen Li; Yun Kuang; Yongtao Meng; Meng-Chang Lin; Huisheng Peng; Hongjie Dai
• Keywords: Science; Q; 02 engineering and technology; 0210 nano-technology; 7. Clean energy; Article; 3. Good health

AbstractRechargeable sodium metal batteries with high energy density could be important to a wide range of energy applications in modern society. The pursuit of higher energy density should ideally come with high safety, a goal difficult for electrolytes based on organic solvents. Here we report a chloroaluminate ionic liquid electrolyte comprised of aluminium chloride/1-methyl-3-ethylimidazolium chloride/sodium chloride ionic liquid spiked with two important additives, ethylaluminum dichloride and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. This leads to the first chloroaluminate based ionic liquid electrolyte for rechargeable sodium metal battery. The obtained batteries reached voltages up to ~ 4 V, high Coulombic efficiency up to 99.9%, and high energy and power density of ~ 420 Wh kg−1 and ~ 1766 W kg−1, respectively. The batteries retained over 90% of the original capacity after 700 cycles, suggesting an effective approach to sodium metal batteries with high energy/high power density, long cycle life and high safety.