Towards the understanding of acetonitrile suppressing salt precipitation mechanism in a water-in-salt electrolyte for low-temperature supercapacitors

doi:10.1039/d0ta04538a

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	Towards the understanding of acetonitrile suppressing salt precipitation mechanism in a water-in-salt electrolyte for low-temperature supercapacitors
	Sun, Yinglun 2,4; Wang, Yue 1; Liu, Lingyang 2,4; Liu, Bao 2,4; Zhang, Qingnuan 2; Wu, Dandan 3; Zhang, Hongzhang 6; Yan, Xingbin 2,4,5
	2020-09-21
关键词	Acetonitrile Capacitance Chlorine compounds Electrolytes Negative ions Positive ions Precipitation (chemical) Sodium compounds Solvents Supercapacitor TemperatureExperimental analysis Hybrid electrolytes Performance degradation Salt precipitation Solvation structure Temperature resistances Theoretical simulation Ultra low temperatures
卷号	8
期号	35
DOI	10.1039/d0ta04538a
页码	17998-18006
英文摘要	Although water-in-salt (WIS) electrolytes have significantly extended the voltage window of aqueous batteries and supercapacitors, the inevitable precipitation of highly concentrated salts at low temperatures leads to performance degradation and even failure of devices. The introduction of an organic co-solvent can effectively overcome this crucial drawback; however, the underlying mechanism remains unclear. Herein, we demonstrate the study of acetonitrile (ACN) suppressing salt precipitation mechanism in NaClO4-based WIS electrolytes through combining theoretical simulation and experimental analyses. ACN molecules strongly coordinate with Na+ions to change the solvation structure of the cation-anion from aggregates to contact ion pairs and/or solvent separated ion pairs, weakening the interaction between anions and cations, thereby suppressing the precipitation of NaClO4. Furthermore, using the hybrid electrolyte, a built carbon-based supercapacitor achieves a voltage window of 2.3 V. Impressively, it also retains 86.5% of the room-temperature capacitance and exhibits excellent rate capability and temperature resistance at an ultra-low temperature of −50 °C. This work provides guidance for non-inert co-solvents suppressing salt precipitation, which helps to obtain desired electrolytes for reliable low-temperature supercapacitors. © The Royal Society of Chemistry 2020.
会议录	Journal of Materials Chemistry A
会议录出版者	Royal Society of Chemistry
语种	英语
ISSN号	20507488
内容类型	会议论文
源URL	[http://ir.lut.edu.cn/handle/2XXMBERH/132707]
专题	图书馆
作者单位	1.School of Physical Science and Technology, Lanzhou University, Lanzhou; 730000, China; 2.Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou; 730000, China; 3.Department of Physics, School of Science, Lanzhou University of Technology, Lanzhou; 730000, China; 4.Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing; 100049, China; 5.International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing; 52600, China 6.Dalian National Laboratory for Clean Energy, Dalian; 116023, China;
推荐引用方式 GB/T 7714	Sun, Yinglun,Wang, Yue,Liu, Lingyang,et al. Towards the understanding of acetonitrile suppressing salt precipitation mechanism in a water-in-salt electrolyte for low-temperature supercapacitors[C]. 见:.