Electrochemical Performance of Sodium Difluoro(oxalato)borate as the Additive of Non-aqueous Electrolytes for Sodium-ion Batteries

Authors

Ding ZHANG, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, 030024, P. R. China;
Qin Zhu, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, 030024, P. R. China;
Ying WANG, Shandong Yuhuang New Energy Technology Co. Ltd. Heze274000, Shandong Province, P. R. China;
Cheng-long ZHAO, Shandong Yuhuang New Energy Technology Co. Ltd. Heze274000, Shandong Province, P. R. China;
Shi-bin LIU, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, 030024, P. R. China;
Shou-dong XU, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, 030024, P. R. China;Follow

Corresponding Author

Shou-dong XU(xushoudong@tyut.edu.cn)

Abstract

Sodium ion battery has attracted worldwide and intensive attention recently, while the adoption of electrolyte additives has been considered as one effective strategy to promote the cell performance. Within this work sodium difluoro(oxalato)borate (NaDFOB) was prepared and adopted as an additive for the general non-aqueous electrolyte formula of 1 mol·L^-1 NaClO₄/EC/PC (Vol: Vol=1:1), and the effects of the additive concentration on ionic conductivity and oxidization decomposition voltage were investigated in detail. In addition, the cell performance evaluated by NaNi_0.5Mn_0.5O₂ as the cathode was also studied. It reveals that the addition of NaDFOB into the NaClO₄/EC/PC electrolyte resulted in the significantly increased oxidation decomposition voltages from 4.6 V to 4.85 V, in spite of the slightly increased ionic conductivity, attributed to extra dissociated sodium salt NaDFOB. When the 0.025 mol·L^-1 NaDFOB added electrolyte was used to support the operation of NaNi_0.5Mn_0.5O₂ cathode, the initial irreversible capacity decreased from 22 mAh·g^-1 to 9 mAh·g^-1, and the capacity retention upon 200 cycles at 0.2 C-rate increased from 44.4% to 89.5%, with an average capacity fade of 0.06 mAh·g^-1 per cycle. Therefore, the NaDFOB was proved to be an effective electrolyte additive for non-aqueous sodium ion batteries.

Graphical Abstract

Keywords

Sodium-ion batteries, non-aqueous electrolyte, electrolyte additive, NaDFOB; NaNi0.5Mn0.5O2

DOI Link

https://doi.org/10.13208/j.electrochem.160703

Publication Date

2017-08-25

Online Available Date

2016-11-02

Revised Date

2016-08-25

Received Date

2016-07-03

Recommended Citation

Ding ZHANG, Qin Zhu, Ying WANG, Cheng-long ZHAO, Shi-bin LIU, Shou-dong XU. Electrochemical Performance of Sodium Difluoro(oxalato)borate as the Additive of Non-aqueous Electrolytes for Sodium-ion Batteries[J]. Journal of Electrochemistry, 2017 , 23(4): 473-479.
DOI: 10.13208/j.electrochem.160703
Available at: https://jelectrochem.xmu.edu.cn/journal/vol23/iss4/12