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Modified graphite felt electrode for all vanadium redox flow battery

  Electrode material is one of the key materials for all vanadium redox flow battery. Graphite felt material due to the large real surface area, good stability and occupy the leading position. But the graphite felt material is poor in hydrophilicity, and the electrochemical activity is not good enough. This paper on the graphite felt electrode respectively chromic acid oxidation method, mixed acid electrochemical oxidation method and hydrothermal ammoniation method for processing vanadium redox flow battery to improve its activity.

  The chromic acid oxidation, hydrophilicity and electrochemical activity of graphite felt electrode significantly enhanced, The increase of oxygen functional groups on the carbon fiber and the surface gully increased, the former increased the carbon fiber surface to participate in the VO2+/VO2+ electrode reaction, which increased the contact area of vanadium ion and electrode.

  Compared with other chemical power supply, vanadium battery has obvious advantages, the main advantages are as follows:

  1 power: by increasing the number of single cell and electrode area, you can increase the power of the vanadium battery, the current U.S. commercial demonstration of the power of the vanadium battery has reached 6MW.

  2 large capacity: increase the volume or improve the vanadium electrolyte concentration can increase consumption, up to more than gwh.

  3 high efficiency: because the electrode catalytic activity of vanadium battery is high, and the positive and negative active substances are stored in positive and negative electrolyte tank, self discharge consumption, energy conversion efficiency as high as 75%, far higher than the lead-acid battery.

  In a lot of electrode materials, carbon electrode has a great advantage in its good stability, and the graphite felt material is dominant in the real surface area. But the graphite felt surface activity is not good, poor hydrophilicity; commercial graphite felt, the conductive properties of imported graphite felt good, graphitization degree is high, but the price is expensive; graphite felt while the cost is low, but the degree of graphitization of low conductivity is poor.