Exceptional capacitance enhancement of a non-conducting COF through potential-driven chemical modulation by redox electrolyte

TitleExceptional capacitance enhancement of a non-conducting COF through potential-driven chemical modulation by redox electrolyte
Publication TypeJournal Article
Year of Publication2021
AuthorsKushwaha, R, Haldar, S, Shekhar, P, Krishnan, A, Saha, J, Hui, P, Vinod, CPrabhakara, Subramaniam, C, Vaidhyanathan, R
JournalAdvanced Energy Materials
Volume11
Issue13
Pagination2003626
Date PublishedAPR
Type of ArticleArticle
ISSN1614-6832
Keywordscovalent organic frameworks, polyiodide, redox electrolytes, solid&\#8208, state capacitors, Supercapacitors
Abstract

Capacitors are the most practical high-storage and rapid charge-release devices. The number of ions stored per unit area and their interaction strength with the electrode dictates capacitor-performance. Microporous materials provide a high storage surface and optimal interactions. Adsorbing electron-rich and easily polarizable molecules into microporous electrodes is expected to boost Faradaic pseudo-activity. If such electrode-electrolyte interactions can be made as a potential-driven reversible process, the resulting capacitors would be adaptable and device-friendly. A composite covalent organic framework (COF)-carbon electrode with redox-active KI is combined in an H2SO4 electrolyte for the first time. This composite electrode benefits from the redox-functionality of COF and electronic conductivity of carbon, leading to superior capacitative activity. Operando spectro-electrochemical measurements reveal the existence of multiple polyiodide species, although the I-3(-) is the predominantly electroactive species adsorbing on the microporous triazine-phenol COF electrode. A systematic fabrication of the flexible solid-state devices using the COF-redox-electrolyte reveals a high areal capacitance of 270 +/- 11 mF cm(-2) and gravimetric capacitance of 57 +/- 8 F g(-1). The inclusion of KI in H2SO4 (electrolyte) yields an approximately eight-fold enhancement in solid-state gravimetric specific capacitance. The imine-COF retains 89% of its capacity even after 10 000 cycles.

DOI10.1002/aenm.202003626, Early Access Date = FEB 2021
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)29.368
Divison category: 
Catalysis and Inorganic Chemistry

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