Determination of the upper and lower potential limits of the activated carbon/propylene carbonate system for electrical double-layer capacitors

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• 作者：Hsiao-Hsuan Shen ; Chi-Chang Hu ; ^{cchu@che.nthu.edu.tw" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Activated carbon ; Propylene carbonate ; Working potential window ; Electrochemical impedance spectroscopy ; Floating test
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2016
• 出版时间：15 October 2016
• 年：2016
• 卷：779
• 期：Complete
• 页码：161-168
• 全文大小：1232 K

文摘

This study demonstrates the criteria for determining the working potential window of commercial activated carbons (ACs) in the propylene carbonate-based (TEABF₄/PC) electrolyte for electrical double-layer capacitors (EDLCs). Through a common potential-floating examination, the working potential window of ACs in 1 M TEABF₄/PC is between − 2.0 and 0.3 V (vs. Ag/AgNO₃). However, an EDLC consisting of the above ACs in 1 M TEABF₄/PC with charge/discharge in this potential window for 1152 cycles shows 27% capacitance loss. The electrochemical impedance spectroscopic (EIS) analyses show the presence of an obvious impedance arc behind the high-frequency semicircle on both positive and negative electrodes after the charge–discharge (CD) cycling. Consequently, a combination of a potential-floating test and EIS analyses precisely determines the working potential window between − 1.9 and 0.2 V, which is a reliable method to efficiently define the working potential window. In this potential range, an EDLC exhibits about 6% capacitance loss during the CD test for 10,000 cycles. The EIS results also reveal an acceptable capacitor behavior after the 10,000-cycle CD test.