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

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

doi:10.1038/s41467-019-11102-2

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

Nat Commun. 2019 Jul 24;10(1):3302. doi: 10.1038/s41467-019-11102-2.

Authors

Hao Sun¹, Guanzhou Zhu¹, Xintong Xu^{1

2}, Meng Liao³, Yuan-Yao Li^{1

4}, Michael Angell¹, Meng Gu⁵, Yuanmin Zhu^{5

6}, Wei Hsuan Hung^{1

7

8}, Jiachen Li¹, Yun Kuang^{1

9}, Yongtao Meng¹, Meng-Chang Lin¹⁰, Huisheng Peng³, Hongjie Dai¹¹

Affiliations

¹ Department of Chemistry, Stanford University, Stanford, CA, 94305, USA.
² School of Aerospace Engineering, Tsinghua University, Beijing, 100084, China.
³ State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China.
⁴ Department of Chemical Engineering, National Chung Cheng University, Chia-Yi, 62102, Taiwan.
⁵ Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
⁶ Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, 518055, China.
⁷ Department of Materials Science and Engineering, Feng Chia University, Taichung, 40724, Taiwan.
⁸ Institute of Materials Science and Engineering, National Central University, Taoyuan, 32001, Taiwan.
⁹ State Key laboratory of Chemical Resource Engineering and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
¹⁰ College of Electrical Engineering and Automation, Shandong University of Science and Technology, Qingdao, 266590, China.
¹¹ Department of Chemistry, Stanford University, Stanford, CA, 94305, USA. hdai@stanford.edu.

Abstract

Rechargeable 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.