The Factors Of Quinone /br Flow Battery Performance And Bromide Ion Penetration

The renewable energy such as wind energy and solar energy is becoming increasingly important along with the increasing demand for energy and paying more attention to the environmental protection. However we are facing with the challenge of intermittency of these sources. The large-scale, high-efficiency energy storage system like vanadium redox flow battery can solve the problem effectively and the vanadium metal ion is the battery’s active substance. So the cost of the battery is higher and it isn’t environmentally friendly. There is a variety of sources of the quinone and it can be "design" based on desired performance. Although organic flow battery is not widespread researched, it is safe, environmentally friendly and low cost, making it great potential for development.An organic flow battery without metal ions was investigate in this paper. Anthraquinone-2-sulfonic sulfuric acid solution was chosen as negative electrolyte and a mixed solution of liquid bromine and hydrobromic was chosen as positive electrolyte. The effects of cell operating conditions on the performance of the new battery were investigated. At the same time, the rate and factors of the bromide ion penetration through the membrane was investigated.Effects of different working conditions on such a flow battery performance were investigated. The results showed that the current could affect the battery performances apparently. When the current increased from 300 mA to 1100 mA, the discharge capacity and the discharge voltage of the battery would reduce, while it was good for the coulomb efficiency. And it also showed that when the charge and discharge current was 900 mA, it could improve discharge capacity, discharge voltage and coulomb efficiency of the battery as the electrolyte flow rate increased from 84 mL/min to 156 mL/min. When the charge and discharge current reduced to 500 mA, there was little effect. It suggested that the current of the flow battery should be controlled within a certain range in actual application. As the current changes, a higher efficiency could be getted by adjusting the flow rate.The bromine ion permeability in a battery was investigated. The results showed that the amount of bromine permeated through changed linearly with time and the bromine permeation rate was slightly different in different currents. When the current increased from 300 mA to 400 mA, the permeation rate of the bromine ion fell from 1.63 × 10-5 mol /(L ? min ? cm2) to 1.52 × 10-5 mol /(L ? min ? cm2). It showed that the increased current was not benefit to the bromine ion permeability. The results also suggested that the permeation rate of bromine during charging and discharging process was slightly different. The permeation rate of bromide ions is about 1.4 × 10-5 mol /(L ? min ? cm2) in the charging process. And the bromide ion permeability of the discharge process is about 1.7 × 10-5 mol /(L ? min ? cm2). These may be due to the internal electric field of the battery. The analysis showed that the process of the bromide ion permeation was affected by diffusion and electromigration, so the permeation rate of bromine during charging and discharging process was differenct.