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Hu L, Deng J, Lin Y, Liang Q, Ge B, Weng Q, Bai Y, Li Y, Deng Y, Chen G, Yu X. Restructuring Electrolyte Solvation by a Versatile Diluent Toward Beyond 99.9% Coulombic Efficiency of Sodium Plating/Stripping at Ultralow Temperatures. Adv Mater 2024; 36:e2312161. [PMID: 38191004 DOI: 10.1002/adma.202312161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/19/2023] [Indexed: 01/10/2024]
Abstract
The reversible and durable operation of sodium metal batteries at low temperatures (LT) is essential for cold-climate applications but is plagued by dendritic Na plating and unstable solid-electrolyte interphase (SEI). Current Coulombic efficiencies of sodium plating/stripping at LT fall far below 99.9%, representing a significant performance gap yet to be filled. Here, the solvation structure of the conventional 1 m NaPF6 in diglyme electrolyte by facile cyclic ether (1,3-dioxolane, DOL) dilution is efficiently reconfigured. DOL diluents help shield the Na+-PF6 - Coulombic interaction and intermolecular forces of diglyme, leading to anomalously high Na+-ion conductivity. Besides, DOL participates in the solvation sheath and weakens the chelation of Na+ by diglyme for facilitated desolvation. More importantly, it promotes concentrated electron cloud distribution around PF6 - in the solvates and promotes their preferential decomposition. A desired inorganic-rich SEI is generated with compositional uniformity, high ionic conductivity, and high Young's modulus. Consequently, a record-high Coulombic efficiency over 99.9% is achieved at an ultralow temperature of -55 °C, and a 1 Ah capacity pouch cell of initial anode-free sodium metal battery retains 95% of the first discharge capacity over 100 cycles at -25 °C. This study thus provides new insights for formulating electrolytes toward increased Na reversibility at LT.
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Affiliation(s)
- Liang Hu
- Department of Mechanical Engineering and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jiaojiao Deng
- Graphene Composite Research Center, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Yuxiao Lin
- School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, Jiangsu Province, 221116, China
| | - Qinghua Liang
- Key Laboratory of Rare Earth, Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi, 341000, China
| | - Bingcheng Ge
- Department of Mechanical Engineering and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong, China
| | - Qingsong Weng
- Department of Mechanical Engineering and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yu Bai
- Shenzhen XFH Science and Technology Co., Ltd., Shenzhen, 518071, P. R. China
| | - Yunsong Li
- Zhejiang Laboratory, Hangzhou, 311100, China
| | - Yonghong Deng
- Department of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Energy Materials for Electric Power, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Guohua Chen
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Xiaoliang Yu
- Department of Mechanical Engineering and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong, China
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