Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (3): 714-719.doi: 10.19799/j.cnki.2095-4239.2020.0019

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Surface modification of carbon fiber paper for vanadium redox flow battery

WANG Qiushi(), SUN Miaomiao, LIU Qinghua, YANG Hong CHEN Jingyun, LIU Junqing, LIANG Wenbin   

  1. National Institute of Clean and Low Carbon Energy, Beijing 102211, China
  • Received:2020-01-07 Revised:2020-03-11 Online:2020-05-05 Published:2020-05-11

Abstract:

Composite carbon fiber electrodes were manufactured by attaching multi-walled carbon nanotubes (MWCNTs) to carbon paper (CP) using the impregnation and carbonization method. The binder between the carbon fiber surface and MWCNT was carbonized to increase the bonding strength and lower the electrical resistance. The composite electrode was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, the BrunauerEmmettTeller specific surface area, cyclic voltammetry, and electrochemical impedance spectroscopy. The composite CP/MWCNT electrodes demonstrated higher surface area (99 m2/g), higher electrochemical activity, lower electrical resistance (0.74 Ω·cm2), and greater hydrophilicity than CP. The CP/MWCNT possessed chemically reactive sites and low charge-transfer resistance and achieved higher energy-conversion efficiency than CP in electrochemical tests. The energy efficiency was maintained at 80% under a chargedischarge current density of 200 mA/cm2 and its peak power density reached 603.32 mW/cm2. This excellent electrochemical performance is mainly attributed to the MWCNT nanostructure formed on the carbon fiber surface. The presented results could pave the way for low-cost electrode manufacturing.

Key words: vanadium redox flow battery, carbon paper, electrode, surface modification

CLC Number: