V₂O₅/Carbon Nanotube/Polypyrrole Based Freestanding Negative Electrodes for High-Performance Supercapacitors

• Main Authors: Jincy Parayangattil Jyothibasu, Ming-Zhu Chen, You-Ching Tien, Chi-Ching Kuo, Erh-Chiang Chen, Yi-Chun Lin, Tai-Chin Chiang, Rong-Ho Lee
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Catalysts
• Subjects: carbon nanotube; freestanding negative electrode; polypyrrole; vanadium pentoxide gel; supercapacitor
• Online Access: https://www.mdpi.com/2073-4344/11/8/980

In this study, the vanadium pentoxide (V₂O₅), functionalized carbon nanotubes (<i>f</i>-CNT), and polypyrrole (PPy) based composites films have been prepared through a facile synthesis method and their electrochemical performance were evaluated as freestanding negative electrodes of supercapacitor. A hydrous V₂O₅ gel prepared by treating V₂O₅ powder with H₂O₂ was mixed with <i>f</i>-CNT to obtain V₂O₅/<i>f</i>-CNT composite film. V₂O₅/<i>f</i>-CNT composite was then coated with PPy through vapor phase polymerization method. The PPy deposited on the V₂O₅/<i>f</i>-CNT prevented the dissolution of V₂O₅ and thus resulted in an improved the capacitance and cycle life stability for V₂O₅/<i>f</i>-CNT/PPy composite electrode. V₂O₅/<i>f</i>-CNT/PPy freestanding negative electrode exhibited a high areal capacitance value (1266 mF cm⁻² at a current density of 1 mA cm⁻²) and good cycling stability (83.0% capacitance retention after 10,000 charge-discharge cycles). The superior performance of the V₂O₅/<i>f</i>-CNT/PPy composite electrode can be attributed to the synergy between <i>f</i>-CNT with high conductivity and V₂O₅ and PPy with high-energy densities. Thus, V₂O₅/<i>f</i>-CNT/PPy composite based electrode can effectively mitigate the drawbacks of the low specific capacitance of CNTs and the poor cycling life of V₂O₅.