Preparation of vanadium electrolyte using asymmetric vanadium reduction cells and application of an asymmetric vanadium reduction cell to rebalance the electrolyte charge state of an operating redox vanadium battery

摘要

"PREPARATION OF VANADIUM ELECTROLYTE USING ASYMMETRICAN VANADIUM REDUCING CELLS AND APPLYING AN ASYMMETRICAN VANADIUM REDUCING CELL" TO REQUIRE THE ELECTRANIATE BALANCY CHARGE STATE OF. The present invention relates to an acid vanadium electrolyte solution containing V V + 3 ^ and V ^ + 4 ^ in a desired concentration ratio from solid vanadium pentoxide fed into the oletrolyte solution, is produced to electrochemically reducing at least part of the vanadium dissolved in the acid electrolyte solution to circulate the electrolyte solution through a plurality of cascade electrolyte cells at least partially to a V ^ + 3 ^ state; reacting the vanadium content thus reduced in an electrolyte solution outlet of the last of the electrolyte cells with a stoichiometric amount of vanadium pentoxide to obtain a vanadium-containing electrolyte solution substantially at a V ^ + 4 ^, adding acid and water to maintain a certain molarity of the solution; and continuously recycle the electrolyte solution through the electrolyte cell cascade while purging a produced electrolyte solution stream containing V ^ + 3 ^ and V ^ + 4 ^ at the desired concentrations at the outlet of one of the cascade cells. Each cell is highly asymmetric, having a cathode and anode with respective surface morphologies, geometry and mutual arrangement such as to establish on the anode surface a current density of 5 to 20 times greater than the current density on the projected cathode surface. and release oxygen at the anode. Such an asymmetric cell can be used in the circuit of one of the positive and negative electrolytes of an operating battery to rebalance the respective oxidation states of its vanadium content.