Redox flow battery system with replaceable barrier electrolyte solution

A redox flow battery system comprising:

• a redox flow battery including a cell having first and second electrodes and an ion-exchange layer arranged there between, the cell supporting electrochemically reversible redox reactions of a positive electrolyte solution and a negative electrolyte solution;
• first and second circulation loops fluidly connected with the first and second electrodes, respectively, of the cell;
• first and second electrolyte storage vessels in the first and second circulation loops, respectively, the first electrolyte storage vessel containing the negative electrolyte solution and the second electrolyte storage vessel containing the positive electrolyte solution;
• and
• at least one ancillary cell fluidly connected with the redox flow battery, the at least one ancillary cell configured to treat at least one of the positive electrolyte solution or the negative electrolyte solution of the redox flow battery by adjusting at least one of a state of charge or a pH of the positive electrolyte solution or negative electrolyte solution.

A method for a redox flow battery system, the method comprises:

• feeding a first electrolyte solution or a first byproduct gas in circulation with a redox flow battery into an ancillary cell;
• oxidizing the first electrolyte solution or the first byproduct gas in the ancillary cell to produce free electrons and ions;
• feeding a second electrolyte solution or a second byproduct gas into the ancillary cell;
• and
• reducing the second electrolyte solution or the second byproduct gas in the ancillary cell.