All vanadium redox flow battery (VRB battery, VRB) is a new type of green environmental protection battery, has the advantages of high efficiency, long service life, safe and reliable, can be used as a large energy storage device, the wind, hydro, solar and other unstable energy into electrical energy storage to be used as a backup power supply has a wide application prospect.
The hydrophilic and electrochemical activity of PAN based (PAN) graphite felt is poor and the graphite felt needs to be modified to be better used in vanadium battery. In order to improve the electrochemical activity of graphite felt, the two cerium oxide was modified on graphite felt by ethanol solution method and sol gel method. Two cerium oxide has the capability of storing and releasing oxygen and the diffusion capacity of fast oxygen vacancies, which is the most active catalyst in rare earth oxides.
Modified graphite felt, in the battery testing of the highest coulomb efficiency can reach 95%, energy efficiency is also close to 90%.Surface deposition method on the surface of graphite felt with catalytic activity of metal, is another kind of modified graphite felt. On the surface of graphite felt were introduced into manganese, cobalt and nickel three metals, and physical and electrochemical properties test of modified graphite felt. The results showed that the modified surface of graphite fiber functional changes, wettability of graphite felt, to improve its electrochemical activity. Battery test results show that the coulomb efficiency can reach 90%.
Graphite felt is a great ratio of carbon fiber surface area, can provide a larger electrochemical reaction for the electrochemical reaction, while the graphite felt has strong oxidation and corrosion resistance, and in addition to the conductive properties of itself, because the graphite felt electrode can be compressed, as battery assembly, contact resistance and bipolar in the small, compared with the metal electrode, the cost is relatively low, is a kind of ideal electrode material.