Nitrogen‐Doped Carbon Felt as an Electrode Material for Vanadium Flow Batteries

Abstract

Vanadium flow batteries (VFBs) are well suited for energy storage due to the attractive features of high safety and long cycle life. Electrodes are a key component of a VFB, directly affecting the energy efficiency and power density of the battery. However, the carbon felt electrode commonly used suffers from poor hydrophilicity and electrochemical activity. Herein, a simple ammonium sulfate hydrothermal method was presented to improve the electrochemical activity and hydrophilicity of carbon felt. In the design, hydrophilic nitrogen‐containing and oxygen‐containing functional groups were introduced in the hydrothermal process, in favor of optimizing the hydrophilicity of carbon felt. The doping of nitrogen with negative charge density and the increasing defects promoted the electrochemical reactions of vanadium ions. Furthermore, the effects of the experimental parameters on the performance of the carbon felt and the battery were carefully studied. As a result, the VFB with 90‐1 nitrogen‐doped carbon felt exhibited the best performance; the energy efficiency achieved 87.34 % at the current density of 80 mA/cm2, which was 3.91 % higher than that with the original one.

Recent advances and perspectives of practical modifications of vanadium redox flow battery electrodes

“…Qiao et al used the ammonium sulphate hydrothermal method to modify the original carbon felt and successfully used nitrogen-doped carbon felt as an electrode material for VRFBs. 112 The influence of the hydrothermal process on the properties of the carbon felt electrode was studied, including elemental analysis, morphology, and electrical behaviour of both raw and modified carbon felt. Yu et al used 1-hydroxyethane-1,1-diphosphonic acid as a phosphorus source to synthesize phosphate-doped graphite felt (PGF) by the hydrothermal method.…”

Electrochemical and Catalytic Properties of Carbon Dioxide-Activated Graphite Felt

“…They are also used to remove polluting substances from water [ 4 , 5 , 6 ]. Another area of use of carbon felt electrodes are batteries [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ] and microbial fuel cells [ 14 , 15 , 16 ]. An important area of research is to characterize [ 17 , 18 , 19 , 20 ] and modify [ 21 , 22 , 23 , 24 , 25 ] the properties of carbon felts.…”