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Efficient Charge Storage in Dual-Redox Electrochemical Capacitors through Reversible Counterion-Induced Solid
Brian Evanko1, Seung Joon Yoo2, Sang-Eun Chun3
1Materials Department, University of California , Santa Barbara, California 93106, United States.
Journal of the American Chemical Society
|July 22, 2016
Summary
Redox-enhanced electrochemical capacitors (redox ECs) show improved performance by retaining electrolytes within electrodes. A new pentyl viologen/bromide electrolyte offers high energy and stability for advanced energy storage.
Area of Science:
- Electrochemistry
- Materials Science
- Energy Storage
Background:
- Redox-enhanced electrochemical capacitors (redox ECs) offer potential for high energy density.
- Electrolyte retention within porous electrodes is crucial for stable and efficient performance.
- Existing methods often face challenges with electrolyte loss and limited stability.
Purpose of the Study:
- To investigate mechanisms for improved electrolyte retention in redox ECs.
- To identify novel electrolyte systems for high-performance electrochemical energy storage.
- To demonstrate design principles for stable and efficient redox ECs.
Main Methods:
- Utilizing reversible counterion-induced solid complexation to retain redox-active species (bromide and viologen).
- Developing and testing a new pentyl viologen/bromide (PV/Br) electrolyte system.
- Characterizing the electrochemical performance, including specific energy, Coulombic efficiency, and cycle stability.
Main Results:
- The PV/Br redox EC achieved a specific energy of 48.5 W·h/kgdry at 0.5 A/gdry.
- Demonstrated exceptional Coulombic efficiency (99.7%) and stability over 10,000 cycles.
- The device operated effectively with reversed polarity, indicating robust design.
Conclusions:
- Reversible counterion-induced solid complexation is an effective strategy for enhancing redox EC performance.
- The pentyl viologen/bromide electrolyte represents a significant advancement in high-performance energy storage.
- This work provides key design principles for future development of stable and efficient electrochemical capacitors.
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