%0 Journal Article %J Advanced Energy Materials %D 2021 %T Exceptional capacitance enhancement of a non-conducting COF through potential-driven chemical modulation by redox electrolyte %A Kushwaha, Rinku %A Haldar, Sattwick %A Shekhar, Pragalbh %A Krishnan, Akshara %A Saha, Jayeeta %A Hui, Pramiti %A Vinod, Chathakudath Prabhakaran %A Subramaniam, Chandramouli %A Vaidhyanathan, Ramanathan %K covalent organic frameworks %K polyiodide %K redox electrolytes %K solid&\#8208 %K state capacitors %K Supercapacitors %X

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.

%B Advanced Energy Materials %V 11 %P 2003626 %8 APR %G eng %N 13 %9 Article %3

Foreign

%4 29.368 %R 10.1002/aenm.202003626, Early Access Date = FEB 2021