Redox fuel cell

PROBLEM TO BE SOLVED: To provide a redox type fuel cell capable of quickly regenerating a mediator.SOLUTION: In a redox type fuel cell that circulates a mediator at a cathode electrode, a regenerator for oxidizing the mediator comprises: a first tank for accommodating mediator-containing liquid; a second tank for accommodating oxygen reduction reaction medium liquid; a power supply; a first electrode installed in the first tank and connected with a positive electrode of the power supply; a second electrode installed in the second tank and connected with a negative electrode of the power supply; an ion exchange path connecting between the first tank and the second tank; and a gas supply device for supplying an oxygen-containing gas to the inside of the second tank. By energizing with the power supply, the mediator is oxidized in the first tank, and the oxygen is reduced in the second tank.