Nonaqueous Electrolyte Development for Electrochemical Capacitors
The objectives of this project were to demonstrate and develop new nonaqueous electrolytes that enable the development of high power (in excess of 2 kW/kg) and high energy (in excess of 8 Wh/kg) capacitors. Electrochemical capacitors are attractive to use because of their long cycle life and inherent high-power (or fast charge/discharge) capabilities. To realize the inherent high-power nature of the capacitor, the resistance of the capacitor needs to be low. The main focus of this project is on the ionic part of capacitor resistance, which is largely determined by the electrolyte, especially the electrolyte's conductivity. To achieve the objectives of this project, two approaches were used. The first was to search for the proper solvent mixtures within the commercially available quaternary ammonium salts such as tetraethyl ammonium tetrafluoroborate (Et4NBF4) or tetraethyl ammonium hexafluorophosphate (Et4NPF6). The second approach was to use the commonly available solvent system s but develop new salts. Substantial advances were made in quaternary ammonium salts and solvent systems were identified that can withstand high voltage operations. However, improvement in the salt alone is not sufficient. Improvements in the low-temperature stability of a capacitor rely not only on the salts but also on the solvents. Likewise, the high-temperature stability of the capacitor will depend not only on the salts but also on the solvents and carbon electrode materials.
- Research Organization:
- USDOE Idaho Operations Office, Idaho Falls, ID (US); U.S. Army Research Laboratory, Adelphi, MD (US)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AI07-96ID13451
- OSTI ID:
- 15050
- Report Number(s):
- DOE/ID/13451; TRN: US200221%%354
- Resource Relation:
- Other Information: PBD: 1 Sep 1999
- Country of Publication:
- United States
- Language:
- English
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