US Patent 7258947 Electrolyte for redox flow battery, and redox flow battery

The present invention provides electrolyte that can suppress reduction of battery efficiencies and capacities with increased cycles of charge/discharge of the battery, a method for producing the same, and a redox flow battery using the same electrolyte. The redox flow battery uses the electrolyte having a NH4 content of not more than 20 ppm and a relation of Si concentration (ppm)×electrolyte quantity (m3)/electrode area (m2) of less than 5 ppm·m3/m2. By limiting a quantity of contaminants in the electrolyte, a clogging of carbon electrodes to cause reduction of the battery performances with increased charge/discharge operations can be suppressed.