HIGH ENERGY DENSITY REDOX FLOW DEVICE

• US 20130344367A1
• Filed: 08/26/2013
• Published: 12/26/2013
• Est. Priority Date: 06/12/2008
• Status: Active Grant

• Current Assignee: 24M Technologies, Inc., Massachusetts Institute of Technology
• Original Assignee: 24M Technologies, Inc., Massachusetts Institute of Technology
• Inventors: Chiang, Yet-Ming, Carter, W. Craig, Ho, Bryan Y., Duduta, Mihai, Limthongkul, Pimpa
• Granted Patent: US 8,722,227 B2
• Time in Patent Office: Days
• US Class Current: 429/101
• CPC Class Codes: B60L 50/72 Constructional details of fuel cells specially adapted for electric vehicles
• CPC Class Codes: B60L 58/27 by heating
• 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: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

Claims

1. An electrode for use in a rechargeable battery, the electrode comprising:

an electrode compartment defined at least partially by a current collector and an ion permeable membrane, the electrode compartment configured to contain an ion-storing redox composition, said ion-storing redox composition comprising a semi-solid or condensed liquid ion-storing redox material that is capable of taking up or releasing ions and that is substantially insoluble in all of its oxidation states, wherein

the electrode has a thickness of about 250 μ

m to about 800 μ

m;

the volume fraction of the ion-storing redox-active material is between 5% and 75%; and

the ion-storing redox composition has an electronic conductivity of at least about 10<sup>−

6</sup> S/cm.

2. The electrode of claim 1, wherein the electroactive composition is free of added binder.

3. The electrode of claim 1, wherein the volume percentage of the ion-storing redox material is greater than 25%.

4. The electrode of claim 1, wherein the volume percentage of the ion-storing redox material is greater than 40%.

5. The electrode of claim 1, wherein the electroactive composition includes a conductive additive and the volume percentage of the total solids including the conductive additive is between 10% and 75%.

6. The electrode of claim 1, wherein the semi-solid or condensed liquid ion-storing redox composition forms a continuously electronically conductive network percolative pathway to the negative current collector and/or the positive current collector.

7. An energy storage device, comprising:

a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating the positive current collector and the negative current collector;

a positive electrode disposed between the positive electrode current collector and the ion-permeable membrane;

the positive electrode current collector and the ion-permeable membrane defining a positive electroactive zone accommodating the positive electrode; and

a negative electrode disposed between the negative electrode current collector and the ion-permeable membrane;

the negative electrode current collector and the ion-permeable membrane defining a negative electroactive zone accommodating the negative electrode;

wherein at least one of the positive electrode and the negative electrode includes a semi-solid or condensed liquid ion-storing redox composition, wherein

the semi-solid or condensed liquid ion-storing redox composition is capable of taking up or releasing ions, remains substantially insoluble during operation of the cell, and has a thickness of about 250 μ

m to about 800 μ

m.

8. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition has an electronic conductivity of at least about 10⁻

6 S/cm.

9. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition has an electronic conductivity of at least about 10⁻

5 S/cm.

10. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition has an electronic conductivity of at least about 10⁻

4 S/cm.

11. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition has an electronic conductivity of at least about 10⁻

3 S/cm.

12. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition forms a continuously electronically conductive network percolative pathway to the negative current collector and/or the positive current collector.

13. The energy storage device of claim 7, wherein the electrode including the semi-solid or condensed liquid ion-storing redox composition is a positive electrode and has an electronic conductivity of about 0.022 S/cm.

14. The energy storage device of claim 7, wherein the electrode including the semi-solid or condensed liquid ion-storing redox composition is a negative electrode and has an electronic conductivity of about 0.025 S/cm.

15. The energy storage device of claim 7, wherein the positive electrode and the negative electrode include a semi-solid or condensed liquid ion-storing redox composition.

16. The energy storage device of claim 7, wherein one of the positive electrode and the negative electrode includes a semi-solid or condensed liquid ion-storing redox composition and the other electrode is a solid electrode.

17. The energy storage device of claim 7, wherein steady state shear viscosity of the semi-solid or condensed liquid ion-storing redox composition is between about 1 cP and 1,000,000 cP at the temperature of operation of the energy storage device.

18. The energy storage device of claim 7, wherein the ion storage compound stores at least one of Li, Na or H.

19. The energy storage device of claim 7, wherein the ion is lithium and the ion storage compound includes an intercalation compound selected from Ax(M′

_1-aM″

_a)_y(XD₄)_z, A_x(M′

_1-aM″

_a)_y(DXD₄)_z, and A_x(M′

_1-aM″

_a)_y(X₂D₇)_z, wherein x, plus y(1-a) times a formal valence or valences of M′

, plus ya times a formal valence or valence of M″

, is equal to z times a formal valence of the XD₄, X₂D₇, or DXD₄ group, and (A_1-aM″

_a)_xM′

_y(XD₄)_z, (A_1-aM″

_a)_xM′

_y(DXD₄)_z and A_1-aM″

_a)_xM′

_y(X₂D₇)_z, wherein (1-a)x plus the quantity ax times the formal valence or valences of M″

plus y times the formal valence or valences of M′

is equal to z times the formal valence of the XD₄, X₂D₇ and DXD₄ group,

where A is at least one of an alkali metal and hydrogen, M′

is a first-row transition metal, X is at least one of phosphorus, sulfur, arsenic, molybdenum, and tungsten, M″

any of a Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at least one of oxygen, nitrogen, carbon, or a halogen.

20. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition includes a conductive additive.

21. The energy storage device of claim 20, wherein the conductive additive forms a percolative conductive continuously electronically conductive network in the semi-solid or condensed liquid ion-storing redox composition.

22. The energy storage device of claim 20, wherein the conductive additive is selected from metal carbides, metal nitrides, carbon black, graphitic carbon powder, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenes, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene sheets, and materials comprising fullerenic fragments that are not predominantly a closed shell or tube of the graphene sheet, and mixtures thereof.

23. The energy storage device of claim 20, wherein the volume percentage of the ion-storing solid phase is between 5% and 70%, and the volume percentage of the total solids including the conductive additive is between 10% and 75%.

24. The energy storage device of claim 7, wherein the semi-solid or condensed liquid ion-storing redox composition is free of added binder.

25. An energy storage device, comprising:

a positive electrode current collector, a negative electrode current collector and an ion permeable membrane disposed between the positive electrode current collector and the negative electrode current collector,

a. the ion permeable membrane spaced from the positive electrode current collector and at least partially defining a positive electroactive zone,

b. the ion permeable membrane spaced from the negative electrode current collector and at least partially defining a negative electroactive zone; and

c. a semi-solid electrode having an electronic conductivity of at least about 10<sup>−

6</sup> S/cm disposed in at least one of the positive electroactive zone and the negative electroactive zone, the semi-solid electrode including a suspension of an ion-storing solid phase material in a non-aqueous liquid electrolyte,

d. the semi-solid electrode having a thickness in the range of about 250 to about 800 μ

m.

26. The energy storage device of claim 25, wherein the volume percentage of the ion-storing solid phase is between 5% and 70%.

27. The energy storage device of claim 25, wherein the semi-solid electrode includes a conductive additive.

28. The energy storage device of claim 27, wherein the volume percentage of the total solids including the conductive additive is between 10% and 75%.

29. The energy storage device of claim 25, wherein the semi-solid electrode is free of added binder.

30. The energy storage device of claim 25, wherein the viscosity of the semi-solid electrode is between about 1 cP and about 1,000,000 cP at the temperature of operation of the energy storage device.