Redox flow battery based on the support a solution containing chloride

PROBLEM TO BE SOLVED: To improve the energy density and the stability of an anolyte and a catholyte of a redox flow battery system.SOLUTION: In a vanadium-based redox flow battery system, an anolyte includes Vand Vions in a supporting solution, Clions are mixed in the supporting solution, a catholyte includes Vand Vin a supporting solution, and Clions are mixed in the supporting solution. In the system, a mixture of SOions and Clions is preferably mixed in the supporting solutions of the anolyte and the catholyte. In the system, the concentration ratio of Cl- to SOis 1:100-100:1, preferably 1:10-10:1, and particularly preferably 1:3-3:1, and the V cation concentration is equal to or greater than 0.5 M, preferably equal to or greater than 1.7 M, and particularly preferably equal to or greater than 2.5 M. In the system, a cell temperature is preferably from -35°C to 60°C or equal to 40°C or above, or a thermal management device actively regulating the cell temperature is not included.SELECTED DRAWING: Figure 3a