| Graphite felt electrode used for vanadium redox flow battery |
| graphite felt |
Electrochemical treatment can improve the activity of graphite felt electrode,
After electrochemical treatment, the O/C ratio of graphite felt surface increased from 0.085 to 0.15, and the main increase was COOH functional groups.
At present, the vanadium battery has been applied in wind power plant, power station,power peaking and solar photovoltaic demonstration operation. The good or bad of electrode materials is a very important factor for the development of vanadium battery.
Electrode material is mainly divided into metal electrode and carbon electrode. In carbon electrode, graphite felt is the dominant position in the surface area of graphite, which is much larger than the surface area. The electrochemical properties of the graphite felt can be greatly improved by the method of concentrated sulfuric acid liquid phase oxidation and air oxidation.
Thermal oxidation method, although the process is simple, less consumption, but the operation elasticity is small, the oxidation reaction is not easy to control. Concentrated sulfuric acid oxidation method using the reagent is very dangerous, industrialized production difficult. And electrochemical oxidation method, the oxidation reaction of ease, easy to control, obvious treatment effect, and is easy to realize the industrialized operation.
Using electrochemical oxidation method for the surface treatment of graphite felt electrode for vanadium battery, the battery charging and discharging performance was excellent, the voltage efficiency of 30m.Acm was 2, and the current efficiency was 92%.
The main change of electrochemical treatment is the ratio of 0/C and the number of oxygen containing functional groups on the carbon fiber surface of graphite felt,especially the amount of COOH.
The graphite felt electrode activity is mainly related to the concentration of C-OH on the surface of the graphite felt electrode.
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