Journal
JOURNAL OF POWER SOURCES
Volume 242, Issue -, Pages 289-298Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jpowsour.2013.05.080
Keywords
Electrical double-layer capacitor; Activated carbon; Charge balance; Electrochemical impedance spectroscopy; Inductance-capacitance-resistance meter
Funding
- National Science Council-Taiwan [NSC 101-2221-E-007-112-MY3, NSC 102-3113-P-006-012]
- boost program from LCERC of National Tsing Hua University
Ask authors/readers for more resources
This study discusses and demonstrates how the open-circuit potential and charges stored in the working potential window on positive and negative electrodes affect the cell voltage of carbon-based electrical double-layer capacitors (EDLCs) in aqueous electrolytes. An EDLC consisting of two activated carbon electrodes is employed as the model system for identifying these key parameters although the potential window of water decomposition can be simply determined by voltammetric methods. First, the capacitive performances of an EDLC with the same charge on positive and negative electrodes are evaluated by cyclic voltammetric, charge discharge, electrochemical impedance spectroscopic (EIS) analyses, and inductance capacitance resistance meter (LCR meter). The principles for obtaining the highest acceptable cell voltage of such symmetric ECs with excellent reversibility and capacitor-like behaviour are proposed. Aqueous charge-balanced EDLCs can be operated as high as 2.0 V with high energy efficiency (about 90%) and only 4% capacitance loss after the 600-cycle stability checking. The necessity of charge balance (but not capacitance balance) for positive and negative electrodes is substantiated from the lower acceptable cell voltage of charge-unbalanced EDLCs. (C) 2013 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available