Separator layer for flow battery

Abstract

A flow battery includes an electrochemical cell that has a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode. The separator layer is formed of a polymer that has a polymer backbone with cyclic groups that are free of unsaturated nitrogen and one or more polar groups bonded between the cyclic groups.

What is claimed is: 
     
         1 . A flow battery comprising:
 an electrochemical cell including a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode,   wherein the separator layer is formed of a polymer having a polymer backbone with aromatic groups that are free of unsaturated nitrogen and one or more polar groups bonded in the polymer backbone.   
     
     
         2 . The flow battery as recited in  claim 1 , wherein the one or more polar groups includes an atom selected from the group consisting of sulfur, oxygen, nitrogen, and combinations thereof. 
     
     
         3 . The flow battery as recited in  claim 1 , wherein the aromatic groups include nitrogen heterocycles. 
     
     
         4 . The flow battery as recited in  claim 1 , wherein the polymer backbone is free of unsaturated nitrogen. 
     
     
         5 . The flow battery as recited in  claim 1 , wherein the polymer includes at least one of adsorbed acid groups or aqueous electrolyte that is non-covalently bonded to the one or more polar groups. 
     
     
         6 . The flow battery as recited in  claim 1 , wherein the polymer includes polyetherimide (PEI). 
     
     
         7 . The flow battery as recited in  claim 1 , wherein the polymer includes polyamide-imide (PAI). 
     
     
         8 . The flow battery as recited in  claim 1 , wherein the polymer includes polyetheretherketone (PEEK). 
     
     
         9 . The flow battery as recited in  claim 1 , wherein the polymer includes polysulfone (PSF). 
     
     
         10 . The flow battery as recited in  claim 1 , wherein the polymer includes polyphenylene sulfide (PPS). 
     
     
         11 . The flow battery as recited in  claim 1 , wherein the polymer is selected from the group consisting of polyetherimide (PEI), polyamide-imide (PAI), polyetheretherketone (PEEK), polysulfone (PSF), polyphenylene sulfide (PPS), and combinations thereof. 
     
     
         12 . The flow battery as recited in  claim 1 , further comprising a supply/storage system external of the electrochemical cell, the supply/storage system including first and second vessels, first and second liquid electrolytes in, respectively, the first and second vessels, fluid lines connecting the first and second vessels to, respectively, the first electrode and the second electrode, and a plurality of pumps operable to circulate the first and second liquid electrolytes via the fluid lines between the first and second vessels and the electrochemical cell. 
     
     
         13 . The flow battery as recited in  claim 1 , wherein the separator layer has an area specific resistance of less than approximately 425 mΩ*cm 2 . 
     
     
         14 . A separator layer for use in a flow battery, the separator layer being formed of a polymer having a polymer backbone with aromatic groups that are free of unsaturated nitrogen, wherein the separator layer has an area specific resistance of less than approximately 425 mΩ*cm 2 . 
     
     
         15 . The separator layer as recited in  claim 14 , wherein the separator layer has an area specific resistance of less than approximately 300 mΩ*cm 2 . 
     
     
         16 . The separator layer as recited in  claim 14 , wherein the polymer is selected from the group consisting of polyetherimide (PEI), polyamide-imide (PAI), polyetheretherketone (PEEK), polysulfone (PSF), polyphenylene sulfide (PPS), polystyrene (PS) and combinations thereof. 
     
     
         17 . A flow battery comprising:
 an electrochemical cell including a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode, and the first electrode and the second electrode are configured to operate at a current density of greater than or equal to approximately 100 mA/cm 2 ; and   a supply/storage system external of the electrochemical cell, the supply/storage system including first and second vessels, first and second liquid electrolytes in, respectively, the first and second vessels, fluid lines connecting the first and second vessels to, respectively, the first electrode and the second electrode, and a plurality of pumps operable to circulate the first and second liquid electrolytes via the fluid lines between the first and second vessels and the electrochemical cell,   wherein the separator layer is formed of a polymer having a polymer backbone with aromatic groups that are free of unsaturated nitrogen and one or more polar groups bonded in the polymer backbone.   
     
     
         18 . A flow battery comprising:
 an electrochemical cell including a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode,   wherein the separator layer is formed of a polymer having a polymer backbone with triazine groups.   
     
     
         19 . The flow battery as recited in  claim 18 , wherein the polymer backbone includes one or more polar groups bonded in the polymer backbone 
     
     
         20 . The flow battery as recited in  claim 19 , wherein the one or more polar groups includes an atom selected from the group consisting of sulfur, oxygen, nitrogen, and combinations thereof.