Inexpensive metal-free organic redox flow battery (orbat) for grid-scale storage

Abstract

A flow battery includes a positive electrode, a positive electrode electrolyte, a negative electrode, a negative electrode electrolyte, and a polymer electrolyte membrane interposed between the positive electrode and the negative electrode. The positive electrode electrolyte includes water and a first redox couple. The first redox couple includes a first organic compound which includes a first moiety in conjugation with a second moiety. The first organic compound is reduced during discharge while during charging the reduction product of the first organic compound is oxidized to the first organic compound. The negative electrode electrolyte includes water and a second redox couple. The second couple includes a second organic compound including a first moiety in conjugation with a second moiety. The reduction product of the second organic compound is oxidized to the second organic compound during discharge.

1 - 11 . (canceled) 
     
     
         12 . A flow battery comprising:
 a positive electrode;   a positive electrode electrolyte including water and a first redox couple, the positive electrode electrolyte flowing over and contacting the positive electrode, the first redox couple including a first organic compound;   a negative electrode;   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode, the second redox couple including a second organic compound, a reduction product of the second organic compound being oxidized to the second organic compound during discharge; and   a polymer electrolyte membrane interposed between the positive electrode and the negative electrode, the negative electrode and/or the positive electrode includes a compound selected from the group consisting of:                                                                                                                  and salts thereof.   
     
     
         13 . A flow battery comprising: 
 a positive electrode;   a positive electrode electrolyte including water and a first redox couple, the positive electrode electrolyte flowing over and contacting the positive electrode, the first redox couple including a first organic compound;   a negative electrode;   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode, the second redox couple including a second organic compound, a reduction product of the second organic compound being oxidized to the second organic compound during discharge; and   a polymer electrolyte membrane interposed between the positive electrode and the negative electrode, wherein the second organic compound has formula 8 or 9:                                             
 wherein R 16 -R 23  are each independently H, NH 2 , —NHR 2 , —N(R 2 ) 2 , —O - M + , —NHCOR 2 , —OR 2 , —CH 3 , —C 2 H 5 , —SO 3 H, , —PO 3 H 2 , —COOH, —OH, —N(R 2 ) 3   + X - , —CF 3 , CCl 3 , —CN, —COOR 2 , F, Cl, Br, —CHO, —COR 2  —O - M + , —SO 3   - M + , —PO 3   2- M +   2 , —COO - M + , pyridinyl, imidazoyl, pyrroyl, or phenyl where R 2  is H or C 1-10  alkyl and M +  is a positively charged counter ion with the proviso that at least one of R 16 -R 23  is an electron donating group. 
     
     
         14 . The flow battery of  claim 13  wherein the second organic compound has the following formula:. 
       
         
           
           
               
               
           
         
       
     
     
         15 . The flow battery of  claim 13  wherein the second organic compound has formula 10: 
       
         
           
           
               
               
           
         
       
        wherein R 24 -R 28  are each independently H, NH 2 , —NHR 2 , —N(R 2 ) 2 , —O - M + , —NHCOR 2 , —OR 2 , —CH 3 , —C 2 H 5 , —SO 3 H, , —PO 3 H 2 , —COOH, —OH, —N(R 2 ) 3   + X - , —CF 3 , CCl 3 , —CN, —COOR 2 , F, Cl, Br, —CHO, —COR 2  —O - M + , —SO 3   - M + , —PO 3   2- M +   2 , —COO - M + , pyridinyl, imidazoyl, pyrroyl, or phenyl where R 2  is H or C 1-10  alkyl and M +  is a positively charged counter ion. 
     
     
         16 . A flow battery comprising:
 a positive electrode;   a positive electrode electrolyte including water and a first redox couple, the positive electrode electrolyte flowing over and contacting the positive electrode, the first redox couple including a first organic compound;   a negative electrode;   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode, the second redox couple including a second organic compound, a reduction product of the second organic compound being oxidized to the second organic compound during discharge; and   a polymer electrolyte membrane interposed between the positive electrode and the negative electrode, wherein the positive electrode electrolyte and/or the negative electrode electrolyte includes a compound selected from the group consisting of:.                                                                     
     
     
         17 . A flow battery comprising:
 a positive electrode;   a positive electrode electrolyte including water and a first redox couple, the positive electrode electrolyte flowing over and contacting the positive electrode, the first redox couple including a first organic compound;   a negative electrode;   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode, the second redox couple including a second organic compound, a reduction product of the second organic compound being oxidized to the second organic compound during discharge; and   a polymer electrolyte membrane interposed between the positive electrode and the negative electrode, wherein the second organic compound has formula 11a, 11b, 12a or 12b:                                                                                         
 wherein R 30 , R 31 , R 32 , R 33  are each independently H, NH 2 , —NHR 2 , —N(R 2 ) 2 , —O - M + , —NHCOR 2 , —OR 2 , —CH 3 , —C 2 H 5 , —SO 3 H, , —PO 3 H 2 , —COOH, —OH, —N(R 2 ) 3   + X - , —CF 3 , CCl 3 , —CN, —COOR 2 , F, Cl, Br, —CHO, —COR 2  —O - M + , —SO 3   - M + , —PO 3   2- M +   2 , —COO - M + , pyridinyl, imidazoyl, pyrroyl, or phenyl where R 2  is H or C 1-10  alkyl and M +  is a positively charged counter. 
     
     
         18 . The flow battery of  claim 17  wherein the second organic compound has formula includes a compound selected from the group consisting of:. 
       
         
           
           
               
               
           
         
       
       
         
           
           
               
               
           
         
       
     
     
         19 . A flow battery comprising:
 a positive electrode;   a positive electrode electrolyte including water and a first redox couple, the positive electrode electrolyte flowing over and contacting the positive electrode, the first redox couple including a first organic compound;   a negative electrode;   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode, the second redox couple including a second organic compound, a reduction product of the second organic compound being oxidized to the second organic compound during discharge; and   a polymer electrolyte membrane interposed between the positive electrode and the negative electrode, wherein the positive electrode electrolyte and/or the negative electrode electrolyte includes a compound selected from the group consisting of:                                                                                                                                                                                                                                                                                                                                                                   .