Electrochemical Energy Storage Systems and Methods Featuring Optimal Membrane Systems

• US 20140030631A1
• Filed: 07/24/2013
• Published: 01/30/2014
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Lockheed Martin Energy LLC (Martin Marietta Corporation)
• Original Assignee: Sun Catalytix Corporation (Martin Marietta Corporation)
• Inventors: ESSWEIN, ARTHUR J., REECE, STEVEN Y., MADDEN, THOMAS H., JARVI, THOMAS D., GOELTZ, JOHN, AMADEO, DESIREE, KING, EVAN R., TYAGI, NITIN
• Granted Patent: US 9,865,893 B2
• Time in Patent Office: Days
• US Class Current: 429/499
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2250/10 Fuel cells in stationary systems, e.g. emergency power source in plant
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: H01M 50/497 Ionic conductivity
• CPC Class Codes: H01M 8/1018 Polymeric electrolyte materials
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: H01M 8/20 Indirect fuel cells, e.g. fuel cells with redox couple being irreversible H01M8/18 takes precedence
• CPC Class Codes: H01M 8/222 Fuel cells in which the fuel is based on compounds containing nitrogen, e.g. hydrazine, ammonia
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

This invention is directed to aqueous redox flow batteries comprising ionically charged redox active materials and separators, wherein the separator is about 100 microns or less and the flow battery is capable of (a) operating with a current efficiency of at least 85% with a current density of at least about 100 mA/cm²; (b) operating with a round trip voltage efficiency of at least 60% with a current density of at least about 100 mA/cm²; and/or (c) giving rise to diffusion rates through the separator for the first active material, the second active material, or both, of about 1×10⁻⁷ mol/cm²-sec or less.

Claims

1. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator;

wherein the flow battery is capable of operating with a current efficiency of at least 85% with a current density of at least about 100 mA/cm² and wherein the separator has a thickness of about 100 microns or less.

2. The flow battery of claim 1, wherein a region of a cell in a flow battery in an on- or off-load condition that is substantially filled with positive and negative electrolytes, wherein the diffusive crossover of active materials represents 2% or less current efficiency loss in an on-load condition in charge or discharge mode.

3. The flow battery of claim 1, wherein a region of a cell in a flow battery in an on- or off-load condition that is substantially filled with positive and negative electrolytes, wherein electrical shorts present in the cell between positive and negative electrodes account for less than or equal to 2% current efficiency loss in an on-load condition in charge or discharge mode.

4. The flow battery of claim 1, wherein a region of a cell in a flow battery in an on- or off-load condition that is substantially filled with positive and negative electrolytes, wherein transference of the charged active materials between positive and negative electrolytes represents 2% or less current efficiency loss in an on-load condition in charge or discharge mode.

5. The flow battery of claim 1, wherein a region of a cell in a flow battery in an on- or off-load condition that is substantially filled with positive and negative electrolytes, wherein an amount of current that is diverted to parasitic reactions represents 4% or less current efficiency loss in an on-load condition in charge or discharge mode.

6. The flow battery of claim 1, wherein a region of a cell in a flow battery in an on- or off-load condition that is substantially filled with positive and negative electrolytes, wherein shunt currents that develop in the fluidic manifolds represent 5% or less current efficiency losses in an on-load condition in charge or discharge mode.

7. The flow battery of claim 1, wherein the first and second active materials are metal ligand coordination compounds.

8. The flow battery of claim 7, wherein the ligand comprises one or more of the following:

CN—

, H₂O, halo, hydroxyl, amines, polyamines, polyalcohols, anions of carboxylic acids, dicarboxylic acids, polycarboxylic acids, amino acids, carbonyl or carbon monoxide carbonyl or carbon monoxide, nitride, oxo, sulfide, pyridine, pyrazine, amido groups, imido groups, alkoxy groups, siloxy, thiolate, catechol, bipyridine, bipyrazine, ethylenediamine, diols, terpyridine, diethylenetriamine, triazacyclononane, trisaminomethane, quinones, hydroquinones, viologens, pyridinium, acridinium, polycyclic aromatic hydrocarbons or combination thereof.

9. The flow battery of claim 1, wherein the metal of the first metal ligand coordination compound comprises one or more of the following atoms:

Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pd, Pt, Ru, Sn, Ti, V, Zn, Zr, or a combination thereof.

10. The flow battery of claim 9, wherein the metal of the first metal ligand coordination compound comprises one or more of the following atoms:

Al, Ca, Co, Cr, Fe, Mg, Ti, V, Zn, Zr, or a combination thereof.

11. The flow battery of claim 1, wherein the metal of the second metal ligand coordination compound comprises one or more of the following atoms:

Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pd, Pt, Ru, Sn, Ti, V, Zn, Zr, or a combination thereof.

12. The flow battery of claim 11, wherein the metal of the second metal ligand coordination compound comprises one or more of the following atoms:

Al, Ca, Co, Cr, Fe, Mg, Ti, V, Zn, Zr, or a combination thereof.

13. The flow battery of claim 1, wherein the metal of the first metal ligand coordination compound and the metal of the second metal ligand coordination compound differ in reduction potential by at least about 0.5 volts.

14. The flow battery of claim 1, wherein the metal of the first metal ligand coordination compound and the metal of the second metal ligand coordination compound differ in reduction potential by at least about 1.0 volt.

15. The flow battery of claim 1, wherein the metal of the first metal ligand coordination compound is the same as the second metal ligand coordination compound;

and wherein the first metal and second metal have different oxidation states.

16. The flow battery of claim 1, wherein the second active material is different from the first active material.

17. The flow battery of claim 1, wherein the mobile ion carries at least about 80% of the ionic current during charge/discharge.

18. The flow battery of claim 1, wherein the mobile ion carries at least about 85% of the ionic current during charge/discharge.

19. The flow battery of claim 1, wherein the mobile ion comprises one or more of the following:

Li⁺, K⁺, Na⁺, Mg²⁺, Ca²⁺, Sr²⁺, Cl⁻

, Br⁻

, I⁻

, OH⁻

or a combination thereof.

20. The flow battery of claim 1, wherein the separator has a thickness of 50 microns or less and the flow battery operates at at least about 98% current efficiency.

21. The flow battery of claim 1, wherein the separator has a thickness of 25 microns or less and the flow battery operates at at least about 96% current efficiency.

22. The flow battery of claim 1, wherein the flow battery is capable of operating with shorting losses of about 1 mA/cm² or less.

23. The flow battery of claim 1, wherein the separator comprises a polymer, wherein the polymer is a cationic exchange membrane comprised of anionic functional groups.

24. The flow battery of claim 23, wherein the polymer comprises one or more of the following:

cross-linked halogenated alkylated compound with a polyamine, a cross-linked aromatic polysulfone type polymer with a polyamine, perfluoriniated hydrocarbon sulfonate ionomers, sulfonated polyetherether ketone (sPEEK), sulfonated poly(phthalazinone ether ketone), sulfonated phenolphthalein poly(ether sulfone), sulfonated polyimides, sulfonated polyphosphazene, sulfonated polybenzimidazole, aromatic polymers containing a sulfonic acid group, sulfonated perfluorinated polymer, fluorinated ionomers with sulfonate groups, carboxylate groups, phosphate groups, boronate acid groups, or combinations thereof, polyaromatic ethers with sulfonate or carboxylate groups, poly(4-vinyl pyridine, poly(2-vinyl pyridine), poly(styrene-b-2-vinylpyridine), poly(vinyl pyrrolidine), poly(1-methyl-4-yinylpyridine), poly[(2,2′

-m-phenylene)-5,5′

-bibenzimidazole][poly(2,2′

-(m-phenylene)-5,5′

-bibenzimidazole], poly(2,5-benzimidazole), polyacrylate, polymethacrylate or combinations thereof.

25. The flow battery of claim 1, wherein the separator comprises a solid polymer, wherein the solid polymer is an anionic exchange membrane comprised of cationic functional groups.

26. The flow battery of claim 25, wherein the polymer comprises one or more of the following:

polydiaryldimethylammonium, poly(methacryloyloxyethyltriethylammonium), poly(diallylammonium), or combinations thereof.

27. The flow battery of claim 1, wherein the polymer comprises one or more of the following:

polytetrafluoroethylene, polyvinyl, polystyrene, polyethylene, polypropylene, polyesters, perfluoriniated polymers, polyvinylidene fluoride, poly(ether-ketone-ether-ketone-ketone), polyvinyl chloride), substituted vinyl polymers, polystyrene, or combinations thereof.

28. The flow battery of claim 27, wherein the membrane further comprises a reinforcement material.

29. The flow battery of claim 28, wherein the reinforcement material comprises one or more of the following:

nylon, cotton, polyesters, crystalline silica, crystalline titania, amorphous silica, amorphous titania, rubber, asbestos wood or combination thereof.

30. The flow battery of claim 29, wherein a volume percent of reinforcement is determined at a given membrane thickness by:

desired thickness=10 μ

m/(1−

reinforcement vol %).

41. The flow battery of claim 1, wherein the separator comprises a porous membrane.

42. The flow battery of claim 41, wherein the separator is a porous membrane and wherein the porous membrane has pores with an average size distribution of between about 0.001 nm and 100 nm.

43. The flow battery of claim 42, wherein the active materials are substantially in the form of a metal-ligand coordination compounds and the average diameter of the metal-ligand coordination compound is about 50% greater than the average pore size of the porous membrane.

44. The flow battery of claim 41, wherein the active materials are substantially in the form of a metal-ligand coordination compounds and the average diameter of the metal-ligand coordination compounds are about 20% larger than the average pore size of the porous membrane when the pore size range is substantially uniform.

45. The flow battery of claim 1, wherein

a. the active materials are substantially in the form of a metal-ligand coordination compounds;

b. the metal-ligand coordination compound has a hydration sphere such that the metal-ligand coordination compound is characterized as having a hydrodynamic diameter; and

c. the hydrodynamic diameter is about 35% larger than the average pore size of the porous membrane.

46. The flow battery of claim 41, wherein

a. the active materials are substantially in the form of a metal-ligand coordination compounds;

b. metal-ligand coordination compounds is further coordinated to at least one water molecule giving rise to a hydrodynamic diameter; and

c. the hydrodynamic diameter is about 10% larger than the average pore size of the porous membrane when the pore size range is substantially uniform.

31. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator having a thickness of about 100 microns or less;

wherein the flow battery is capable of operating with a round trip voltage efficiency of at least 60% with a current density of at least about 100 mA/cm².

32. The flow battery of claim 31, wherein the flow batter is capable of operating with a voltage efficiency of at least about 60%, of at least about 70%, of at least about 80%, or of at least about 90%.

33. The flow battery of claim 31, wherein the second active material being different from the first active material.

34. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator of thickness of about 100 microns or less and capable of having a selectivity in a range of from about 50 to about 1,000,000 for one mobile ion over the first and second active materials.

35. The flow battery of claim 34, wherein the separator is capable of having a selectivity in a range of about 50 to about 300 for at least one mobile ion over the first and second active materials.

36. The flow battery of claim 34, wherein the separator is capable of having a selectivity in a range of from 100 to about 1000 for at least one mobile ion over the first and second active centers.

37. The flow battery of claim 34, wherein the second active material being different from the first active material.

38. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator having a thickness of about 100 microns or less and capable of giving rise to diffusion rates through the separator for the first active material, the second active material, or both, to be 1×

10<sup>−

7</sup> mol/cm²-sec or less.

39. The flow battery of claim 38, wherein the first active material, the second active material, or both, have a diffusion rate through the separator of 1×

10⁹ mol/cm²-sec or less, 1×

10<sup>−

11</sup> mol/cm²-sec or less, 1×

10<sup>−

13</sup> mol/cm²-sec or less, or 1×

10<sup>−

15</sup> mol/cm²-sec or less.

40. The flow battery of claim 38, wherein the second active material being different from the first active material.

47. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

wherein the first active material has a net ionic charge;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

wherein the second active material has a net ionic charge;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator of thickness of about 100 microns or less, the separator comprising an ionomer membrane;

wherein the net ionic charge of the first, second, or both active materials matches that of the ionomer membrane; and

wherein the flow battery is capable of operating with a current efficiency of at least 90% with a current density of at least 100 mA/cm².

48. The flow battery of claim 47, wherein the ionomer has an ionomer mass to molar content on an areal basis of 2×

10<sup>−

3</sup> g ionomer/cm² or less.

49. A flow battery, comprising:

a first electrolyte comprising an aqueous solution comprising a first active material containing at least one mobile ion;

a second electrolyte comprising an aqueous solution comprising a second active material and at least one mobile ion;

a first electrode in contact with said first aqueous electrolyte;

a second electrode in contact with said second aqueous electrolyte; and

a separator of thickness of about 100 microns or less, wherein the separator has a plurality of layers wherein at least one layer is capable of ionic conduction and at least one other layer is capable of selective ion transport; and

wherein the flow battery is capable of operating with a current efficiency of at least 90% with a current density of at least about 100 mA/cm².

50. The flow battery of claim 49, wherein the at least one layer comprises at least one of the first electrolyte or the second electrolyte to be imbibed onto the separator.

51. The flow battery of claim 49, wherein a desired areal resistance range for the imbibed separator is determined by R_total[ohm-cm²]=K_membrane/10⁻

6 m+(porosity_sep̂

1.5*K_electrolyte)/thickness_sep.

52. The flow battery of claim 49, wherein the at least one other layer capable of selective ion transport comprises one or more of the following:

perfluorinated sulfonate polymer, perfluoriniated hydrocarbon sulfonate ionomers, sulfonated polyetherether ketone (sPEEK), sulfonated poly(phthalazinone ether ketone), sulfonated phenolphthalein poly(ether sulfone), sulfonated polyimides, sulfonated polyphosphazene, sulfonated polybenzimidazole, polyaromatic ethers with sulfonic or carboxylic acid groups, or combinations thereof.

53. The flow battery of claim 49, wherein at least one layer of the plurality of layers is a porous membrane.