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Cost Effective, Optimized Vanadium Based Aqueous Electrolytes

Description:

Liquid electrolyte in RFB serves as a “fuel” to store electricity via redox reactions when flowing through electrodes. The liquid electrolyte determines the energy capacity and is a main component to the overall capital cost and technical performance. This is particular true for the all-vanadium RFBs or VRBs. The current electrolytes in vanadyl sulfate systems account for nearly 40% of the total cost of a 1MW/8MWh all vanadium system. The high cost comes from vanadium and
preparation of high purity of the vanadium aqueous electrolytes. There is also a stability issue in the current sulfate electrolytes. When the vanadium concentration is over 2 M, the electrolytes will become super saturated, resulting in formation of precipitation for V5+ at the temperatures above 40°C and for V2+, V3+, V4+ at the temperatures below 10°C. Accordingly, current VRBs are limited to around 1.7 M and operated in 10-35oC, with heat management required. As such grant applications are sought to develop cost-effective, optimized aqueous vanadium base electrolytes that can demonstrate: 1) high solubility of active components and stability over broad operating conditions, 2) excellent electrochemical reversibility, 3) good chemical compatibility to adjacent components such as electrodes, tubes, etc. 4) acceptance to environment, and 5) most of all, low cost by reduction of vanadium use and simplification of electrolyte preparation.

Questions – contact Imre Gyuk, imre.gyuk@hq.doe.gov

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