Redox flow battery

Abstract

A redox flow (RF) battery is provided that performs charge and discharge by supplying a positive electrode electrolyte and a negative electrode electrolyte to a positive electrode cell and a negative cell, respectively. Each of the positive and negative electrode electrolytes contains a vanadium (V) ion as active material. At least one of the positive and negative electrode electrolytes further contains another metal ion, for example, a manganese ion that exhibits a higher redox potential than a V ion or a chromium ion that exhibits a lower redox potential than a V ion. Even in cases where the RF battery is nearly fully charged, side reactions such as generation of oxygen has or hydrogen gas due to water decomposition and oxidation degradation of an electrode can be suppressed since the above-mentioned another metal ion contained together with the V ion is oxidized or reduced in the late stage of charge.

1 . 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.   
     
     
         2 . The redox flow battery according to  claim 1 , wherein at least said positive electrode electrolyte further contains a metal ion higher in redox potential than the vanadium ion. 
     
     
         3 . The redox flow battery according to  claim 1 , wherein each of said positive electrode electrolyte and said negative electrode electrolyte further contains a metal ion higher in redox potential than the vanadium ion. 
     
     
         4 . The redox flow battery according to  claim 1 , wherein
 said metal ion higher in redox potential is at least one type of metal ions selected from a manganese ion, a lead ion, a cerium ion, and a cobalt ion, and   a total concentration of said metal ion higher in redox potential in an electrolyte containing said metal ion higher in redox potential is not less than 0.1M and not more than 5M.   
     
     
         5 . The redox flow battery according to  claim 1 , wherein said metal ion higher in redox potential is at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion. 
     
     
         6 . The redox flow battery according to  claim 1 , wherein the electrolyte containing said metal ion higher in redox potential contains at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion, and tetravalent manganese. 
     
     
         7 . The redox flow battery according to  claim 1 , wherein
 at least said positive electrode electrolyte further contains a metal ion higher in redox potential than the vanadium ion, and   at least said negative electrode electrolyte further contains a metal ion lower in redox potential than the vanadium ion.   
     
     
         8 . The redox flow battery according to  claim 1 , wherein at least one of said positive electrode electrolyte and said negative electrode electrolyte further contains each of the metal ion higher in redox potential than the vanadium ion and the metal ion lower in redox potential than the vanadium ion. 
     
     
         9 . The redox flow battery according to  claim 1 , wherein
 said metal ion higher in redox potential is at least one type of metal ions selected from a manganese ion, a lead ion, a cerium ion, and a cobalt ion,   said metal ion lower in redox potential is at least one type of metal ions of a chromium ion and a zinc ion, and   each of a total concentration of the metal ions higher in redox potential in an electrolyte containing said metal ions higher in redox potential and a total concentration of the metal ions lower in redox potential in an electrolyte containing said metal ions lower in redox potential is not less than 0.1M and not more than 5M.   
     
     
         10 . The redox flow battery according to  claim 1 , wherein
 said metal ion higher in redox potential is at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion, and   said metal ion lower in redox potential is at least one type of chromium ions of a divalent chromium ion and a trivalent chromium ion.   
     
     
         11 . The redox flow battery according to  claim 1 , wherein
 the electrolyte containing said metal ion higher in redox potential contains at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion, and tetravalent manganese, and   said metal ion lower in redox potential is at least one type of chromium ions of a divalent chromium ion and a trivalent chromium ion.   
     
     
         12 . The redox flow battery according to  claim 1 , wherein at least said negative electrode electrolyte further contains a metal ion lower in redox potential than the vanadium ion. 
     
     
         13 . The redox flow battery according to  claim 1 , wherein each of said positive electrode electrolyte and said negative electrode electrolyte further contains a metal ion lower in redox potential than the vanadium ion. 
     
     
         14 . The redox flow battery according to  claim 1 , wherein
 said metal ion lower in redox potential is at least one type of metal ions of a chromium ion and a zinc ion, and   a total concentration of the metal ions lower in redox potential in an electrolyte containing said metal ions lower in redox potential is not less than 0.1M and not more than 5M.   
     
     
         15 . The redox flow battery according to  claim 1 , wherein said metal ion lower in redox potential is at least one type of chromium ions of a divalent chromium ion and a trivalent chromium ion. 
     
     
         16 . The redox flow battery according to  claim 1 , wherein each of said positive electrode electrolyte and said negative electrode electrolyte contains a sulfate anion. 
     
     
         17 . The redox flow battery according to  claim 1 , wherein
 a solvent of each of said positive electrode electrolyte and said negative electrode electrolyte is an H 2 SO 4  aqueous solution, and   a sulfuric acid concentration of each of said positive electrode electrolyte and said negative electrode electrolyte is not more than 5M.   
     
     
         18 . The redox flow battery according to  claim 1 , wherein an operation is performed such that a state of charge of an electrolyte of an electrode containing at least one of said metal ion higher in redox potential and said metal ion lower in redox potential exceeds 90%.