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Are Functional Groups Beneficial or Harmful on the Electrochemical Performance of Activated Carbon Electrodes?

Ding, Ziming; Trouillet, Vanessa; Dsoke, Sonia

It is a common opinion that activated carbon (AC) should be functional groups-free when employed as capacitor-type material in organic electrolytes. This work analyzes in detail the relationship between the electrochemical performance of modified activated carbon electrodes and the introduced functional groups in two organic electrolytes containing lithium salts:1M LiPF6 in EC-DMC (the commercial LP30) and 1M LiTFSI in EC-DMC. The surface functional groups (especially C=O or O–C=O) can induce higher capacitance to AC (more than 50% increase compared to commercial unmodified AC), whereas the rate capability dramatically decreases. The appropriate amount of functional groups is helpful to expand the electrochemical stability window in LP30 (2.8–2.9 V), that is responsible for the high energy and power density. Moreover, the proper functional groups inhibit the potential shift of the AC electrode. However, a large number of functionalities can result in a high amount of irreversible redox products remaining in the pores of AC, which leads to a faster capacitance fade respect to materials with less functional groups.

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Verlagsausgabe §
DOI: 10.5445/IR/1000093180
Veröffentlicht am 02.04.2019
DOI: 10.1149/2.0451906jes
Seitenaufrufe: 21
seit 04.04.2019
Downloads: 15
seit 08.04.2019
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Energiespeichersysteme (IAM-ESS)
Helmholtz-Institut Ulm (HIU)
Karlsruhe Nano Micro Facility (KNMF)
Publikationstyp Zeitschriftenaufsatz
Jahr 2019
Sprache Englisch
Identifikator ISSN: 0013-4651, 1945-7111
KITopen-ID: 1000093180
HGF-Programm 37.01.12 (POF III, LK 01)
Erschienen in Journal of the Electrochemical Society
Band 166
Heft 6
Seiten A1004–A1014
Vorab online veröffentlicht am 27.03.2019
Schlagworte Energy Storage; Power Sources; Supercapacitors; activated carbon; ageing; functional groups
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