Crossover resistant materials for aqueous organic redox flow batteries

Abstract

An organic flow battery having a positive electrode electrolyte containing organic compounds with extended conjugation and/or cyclic side chains is provided. The flow battery includes a positive electrode and a positive electrode electrolyte including first solvent and a first redox couple. The positive electrode electrolyte flows over and contacting the positive electrode. The first redox couple includes a first organic compound and a reduction product of the first organic compound. The flow battery also includes a negative electrode and a negative electrode electrolyte including a second solvent and a second redox couple. The negative electrode electrolyte flows g over and contacts the positive electrode. Typically, an ion exchange membrane is interposed between the positive electrode and the negative electrode Characteristically, the first organic compound resists crossover through the ion exchange membrane.

1 .- 10 . (canceled) 
     
     
         11 . 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 and a reduction product of the first organic compound,   a negative electrode; and   a negative electrode electrolyte including water and a second redox couple, the negative electrode electrolyte flowing over and contacting the positive electrode; and   an ion exchange membrane interposed between the positive electrode and the negative electrode, wherein the ion exchange membrane impedes crossover therethrough.   
     
     
         12 . The flow battery of  claim 11  wherein the ion exchange membrane has a water content less than about 40 weight percent of the total weight of the ion exchange membrane. 
     
     
         13 . The flow battery of  claim 11  wherein the ion exchange membrane has an acid equivalent weights greater than 1100 g/mole of protons. 
     
     
         14 . The flow battery of  claim 11  wherein the ion exchange membrane is selected from the group consisting of perfluorohydrocarbon membranes and sulfonated hydrocarbon membranes with an arene or substituted arene backbone backbone. 
     
     
         15 . The flow battery of  claim 14  wherein sulfonated hydrocarbon membranes are sulfonated polyether-ether ketone, sulfonated polyethersulfone, or polystyrene-sulfonic acid based membranes. 
     
     
         16 . The flow battery of  claim 11  wherein the first redox couple including a first organic compound and a reduction product of the first organic compound such that the first organic compound resists crossover through the ion exchange membrane. 
     
     
         17 . The flow battery of  claim 11  wherein the first organic compound has an acidity greater than the acidity of the ion exchange membrane.