Redox flow battery

A redox flow battery performing charge and discharge by supplying a positive electrode electrolyte and a negative electrode electrolyte to a battery cell, each of said positive electrode electrolyte and said negative electrode electrolyte containing a vanadium ion, and at least one of said positive electrode electrolyte and said negative electrode electrolyte further containing at least one of a metal ion higher in redox potential than the vanadium ion and a metal ion lower in redox potential than the vanadium ion.