Electrospun carbon nanofiber inlaid with tungsten carbide nanoparticle by in-situ carbothermal reaction as bifunctional electrode for vanadium redox flow battery. (1st December 2020)

• Record Type: Journal Article
• Authors: Cheng, Gang; Jiang, Yingqiao; Li, Yuehua; Chen, Jian; He, Zhangxing; Meng, Wei; Dai, Lei; Wang, Ling
• Is Part Of: Electrochimica acta. Volume 362(2020)
• Publication Date: 2020-12-01
• Subjects: Vanadium redox flow battery -- Bifunctional electrode -- Electrospun carbon nanofiber -- Tungsten carbide -- Electrocatalysis; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.137178
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: This work provided a novel tungsten carbide (WC) nanoparticle catalyst which was uniformly inlaid in carbon nanofiber (CNF) without help of binder by in-situ carbothermal reaction and electrospinning technology to obtain CNF/WC composite for use as bifunctional electrode for vanadium redox flow battery (VRFB). Ammonium tungstate was used as tungstate source to obtain CNF/WC composites consisting of different amounts of WC (CNF/WC-05, CNF/WC-10, and CNF/WC-20). Ammonium tungstate was decomposed to tungsten trioxide at high temperature, which was subsequently converted to WC by way of an in-situ carbothermal reaction with increasing temperature. The electrochemical performance of CNF/WC composite is improved due to that WC nanoparticle can increase active sites towards vanadium redox reaction. CNF/WC-10 presents the best electrochemical performance for V 3+ /V 2+ redox reaction as well as an increase in electrochemical performance for VO 2+ /VO2 + redox reaction compared with CNF. The cell using CNF/WC-10 as bifunctional electrode exhibits an increase in energy storage performance including higher energy efficiency and discharge capacity. In comparison with pristine cell, the cell using CNF/WC-10 shows better stability in 50-cycle charge-discharge operation at 50 mA cm −2 . Especially, the cell using CNF/WC-10 presents an increase in energy and voltage efficiency compared with pristine cell at high current density, suggesting that CNF/WC-10 electrode decreases electrochemical polarization of cell. At 150 mA cm −2, the cell using CNF/WC-10 presents an increase of 7.2% in energy efficiency compared with pristine cell (61.1%). Overall, the results demonstrate excellent electrochemical performance of WC for vanadium redox reaction and provide guidelines for exploring carbide catalyst in future VRFB study.