Introducing Electrochemically Active Oxygen Species to Boost the Pseudocapacitance of Carbon‐based Supercapacitor. Issue 16 (13th July 2021)

• Record Type: Journal Article
• Authors: Hu, You Ren; Dong, Xiao Ling; Zhuang, Hong Kun; Yan, Dong; Hou, Lu; Li, Wen Cui
• Is Part Of: ChemElectroChem. Volume 8:Issue 16(2021)
• Page Start: 3073
• Page End: 3079
• Publication Date: 2021-07-13
• Subjects: supercapacitors -- carbon-based electrodes -- electrochemical oxidation -- high energy density -- oxygen-containing functional groups; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202100641
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: Low energy density is the main bottleneck for carbon‐based supercapacitors, which can be addressed by introducing extra faradaic pseudocapacitance. Herein, a cyclic voltammetry oxidation method in 1 M H2 SO4 electrolyte was employed for carbon electrode to produce electrochemically active oxygen functional groups that are in contact with the conductive substrates, which facilitates the implementation of the pseudocapacitance. Moreover, the influence of potential window and sweep rate on the components and performances of oxidized electrodes in the cyclic voltammetry oxidation process was systematically investigated. The results reveal that a broad potential window of −0.65∼2 V can enhance the oxygen content to 16.4 wt.% (vs. 7.6 wt.% within −0.65∼1.5 V). Additionally, a selective oxygen component dominated with redox active C−OH and C=O groups was achieved by a rapid potentiodynamic sweep at 20 mV s −1, simultaneously suppressing the ‐COOH groups with inferior conductivity. The oxidized AC electrodes could substantially improve the specific capacitance (534 vs. 150.3 F g −1 at 1 A g −1 ) without sacrifice of rate performance (retained 418 F g −1 at 20 A g −1 ), accompanying excellent cycling stability of 94 % of initial capacitance after 10000 cycles. Such finding would provide some reference for tailoring oxygen species to fabricate advanced carbon‐based supercapacitor electrodes. Abstract : A cyclic voltammetry oxidation method for carbon electrode is proposed to boost pseudocapacitance substantially. As abundant electrochemically active and reversible C−OH/C=O groups are selectively introduced without excessive sacrifice of conductivity during the rapid multiple cyclic voltammetry oxidation, the oxidized electrode delivers a super‐high capacitance of 534 F g −1 with good rate and cycle performance.