A redox flow battery includes a positive electrode electrolyte and a negative electrode electrolyte, each of which includes a metal-ligand coordination complex, in which a metal of a metal-ligand coordination complex of the positive electrode electrolyte is different from a metal of a metal-ligand coordination complex of the negative electrode electrolyte. Due to use of different metals in the positive and negative electrode electrolytes, the redox flow battery has high energy density and high charge and discharge efficiency.