The Study On The Flow Battery Based On Quinones

With the energy crisis and greenhouse effect, more and more countries are devoted to the exploration of new energy. The energy storage devices show a very important role in the utilization of solar and wind power and the load shifting of the grid. As the strong designability and good cycling performance, flow batteries are intended to be the next generation of energy storage device. At present, a lot of flow battery technologies depend on the redox metal materials. The flow battery researched in this paper adopts the organic molecules in quinone species as the electroactive material. The introducing of quinone species can avoid the use of redox metals, decrease the cost of the cell, and make the cell more environmentally-friendly. The quinone species is abundant, and will not suffer from the resource constraints.Firstly, this paper builds a quinone bromine flow battery with the anthraquinone-2-sulfonic acid as the negative material and the bromine as the positive material. The bromine crossover behavior is explored by a spectrophotometer, and the durability of the cell is researched by XRD, NMR and SEM. Then the electrochemical characteristics of the quinone species are studies by the electrochemical measurement. Last, the all quinone flow cell is build using 3,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid and 1,2-benzoquinone-3,5-disulfonic acid.The quinone bromine flow cell has a good reversible performance, but the bromine crossover is found to be inevitable in the cell operation. Increasing the Br concentration or increasing the flow rate should increase the Br crossover speed,but increasing current density should restrain the Br crossover. The permeation of the bromine will get a balance in the cell finally. Br— and Br2 should cause the crossover behavior together. But only the Br2 crossover can induce the self-discharge reaction in the cell, causing the current inefficiency. The carbon paper can maintain the stable structure during cell operation. Anthraquinone-2-sulfonic acid is a promising candidate of the material in the flow cell as it expresses a good cycling performance and has a stable molecular structure in the cell.The electrochemical analysis shows the anthraquinone-2-sulfonic acid, 3,4-dihydroxy-9,10-anthraquinone-2-sulfonic acid and 1,2-benzoquinone-3,5-disulfonic acid express a good electrochemical reversibility in the acid solution, and have a fast kinetic rate constant on the carbon electrode, respectively. These traits make them suitable for using in the flow cell. The all quinone flow cell in this paper expresses a good cycling performance. Instead of using the bromine in the electrolyte, the cell can be more secure.