Jump to main content
Jump to site search

Issue 35, 2020
Previous Article Next Article

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

Author affiliations

Abstract

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.

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

Back to tab navigation

Supplementary files

Article information


Submitted
30 Apr 2020
Accepted
28 Jul 2020
First published
28 Jul 2020

J. Mater. Chem. A, 2020,8, 17998-18006
Article type
Paper

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

Y. Sun, Y. Wang, L. Liu, B. Liu, Q. Zhang, D. Wu, H. Zhang and X. Yan, J. Mater. Chem. A, 2020, 8, 17998
DOI: 10.1039/D0TA04538A

Social activity

Search articles by author

Spotlight

Advertisements