(Invited) Interaction of Anions with Partially Oxidized Carbon Nanotubes and the Influence on the Performance of Polypyrrole-Carbon Nanotube Composite Electrodes

Wei, Chaohui; Akinwolemiwa, Bamidele; Yu, Linpo; Hu, Di; Xia, Lan; Chen, George Zheng

Abstract

Partial oxidation of carbon nanotubes (CNTs) in mixed HNO3 and H2SO4 is commonly used for the preparation of polymer-CNT composites. This procedure, however, emits toxic NOx fumes, making it difficult for commercial scale-up. Herein we report an environment-friendly new method which utilizes mixed H2O2 and H2SO4 to partially oxidize CNTs to produce composite electrodes with polypyrrole (PPy). With the aid of Raman, Fourier Transform Infrared, and X-ray photoelectron spectroscopic techniques, the physiochemical properties of the CNTs prepared from H2O2 aided oxidation were compared with those CNTs treated in HNO3 aided oxidation. Furthermore, through cyclic voltammetry, electrochemical impedance spectroscopy, and electrochemical quartz-crystal microbalance, the interaction of the doping anions (Cl-, SO42-, etc.) with partially oxidized CNTs were studied and used to explain the performance of different PPy-CNT composites. Results showed that the capacitance of the composite with CNTs treated by H2O2 aided oxidation (ca. 156.0 F/g) was comparable to that with CNTs treated by HNO3 aided oxidation (ca. 163.0 F/g). Furthermore, the need for critically appraising the charge storage mechanism on the carbons used in making the PPy-CNT composites is emphasized, and general observations that various oxygen containing functional groups could contribute in different ways to the observed charge storage mechanism of both the oxidized CNTs and their corresponding polymer composites were also explained. It can thus be predicted that the H2O2 aided partial oxidation of CNTs is suitable for producing high performance polymer composite electrodes, and the new process is promising for commercial scale-up with low environmental impact.

• Presentation Conference Type: Keynote
• Conference Name: AiMES 2018 Meeting
• Conference Location: Cancun, Mexico
• Start Date: Sep 30, 2018
• End Date: Oct 4, 2018
• Deposit Date: Jun 17, 2023
• Publisher: Electrochemical Society
• DOI: https://doi.org/10.1149/ma2018-02/55/1968
• Public URL: https://nottingham-repository.worktribe.com/output/7356650
• Publisher URL: https://iopscience.iop.org/article/10.1149/MA2018-02/55/1968
• Additional Information: Paper given at AiMES 2018 Meeting September 30, 2018 - October 4, 2018 Cancun, Mexico (L05-Electroactive and Redox Active Polymers 2)