Redox fuel cells with a catholyte solution containing a polyoxometallate

• US 9,005,828 B2
• Filed: 03/23/2007
• Issued: 04/14/2015
• Est. Priority Date: 03/24/2006
• Status: Expired due to Fees

• Current Assignee: Clean Power Limited
• Original Assignee: ACAL Energy Ltd
• Inventors: Creeth, Andrew Martin, Potter, Andrew Robert
• Primary Examiner(s): Cullen, Sean P
• Application Number:
  US12/294,320
• Publication Number:
  US 20090317668A1
• Time in Patent Office: 2,944 Days
• Field of Search: 429/417, 429/447, 429/492, 429/502
• US Class Current: 429/417
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/9016 Oxides, hydroxides or oxygenated metallic salts
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1025 having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
• CPC Class Codes: H01M 8/1027 having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/1032 having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• 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

Abstract

This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution comprising at least about 0.075M of the said polyoxometallate.

Claims

1. A redox fuel cell comprising:

a fuel for the redox fuel cell;

an anode region comprising an anode and a cathode region comprising a cathode, said regions being separated by an ion selective polymer electrolyte membrane;

a fuel passage through which the fuel is supplied to the anode region of the cell;

an oxidant inlet that supplies an oxidant to the cathode region of the cell;

an electrical circuit between the anode and the cathode; and

a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising at least about 0.1M of a polyoxometallate, wherein the polyoxometallate of the catholyte solution is not present in the fuel, and wherein the polyoxometallate is at least partially reduced at the cathode in operation of the cell, and at least partially regenerated by reaction with the oxidant after such reduction at the cathode.

2. A redox fuel cell according to claim 1 wherein the concentration of the polyoxometallate in the catholyte solution is over 0.15M.

3. A redox cell according to claim 1 wherein the catholyte solution is substantially free from any ancillary redox species.

4. A redox fuel cell according to claim 1 wherein the catholyte solution comprises at least one ancillary redox species.

5. A redox fuel cell according to claim 4 wherein the ancillary redox species is selected from ligated transition metal complexes, further polyoxometallate species, and combinations thereof.

6. A redox fuel cell according to claim 5 wherein the transition metal(s) in the transition metal complexes is/are selected from the group consisting of:

manganese in oxidation states II-V, Iron I-IV, copper I-III, cobalt I-III, nickel I-III, chromium (II-VII), titanium II-IV, tungsten IV-VI, vanadium II-V and molybdenum II-VI.

7. A redox fuel cell according to claim 1 wherein the polyoxometallate is represented by the formula:

X_a[Z_bM_cO_d]

wherein;

X is selected from the group consisting of;

hydrogen, alkali metals, alkaline earth metals, and ammonium, and combinations of two or more thereof;

Z is selected from the group consisting of;

B, P, S, As, Si, Ge, Ni, Rh, Sn, Al, Cu, I, Br, F, Fe, Co, Cr, Zn, H₂, Te, Mn and Se, and combinations of two or more thereof;

M is a metal selected from the group consisting of;

Mo, W, V, Nb, Ta, Mn, Fe, Co, Cr, Ni, Zn, Rh, Ru, Tl, Al, Ga, In, metals selected from the 1st, 2nd and 3rd transition metal series, and the lanthanide series, and combinations of two or more thereof;

a is a number of X necessary to charge balance the [Z_bM_cO_d] anion;

b is from 0 to 20;

c is from 1 to 40; and

d is from 1 to 180.

8. A redox fuel cell according to claim 7 wherein b is from 0 to 2.

9. A redox fuel cell according to claim 7 wherein c is from 5 to 20.

10. A redox fuel cell according to claim 7 wherein d is from 30 to 70.

11. A redox fuel cell according to claim 7 wherein M is selected from the group consisting of:

vanadium, molybdenum, and combinations thereof.

12. A redox fuel cell according to claim 7 wherein Z is phosphorus.

13. A redox fuel cell according to claim 7 wherein X comprises a combination of hydrogen with alkali metal ions and/or alkaline earth metal ions.

14. A redox fuel cell according to claim 7 containing from 2 to 4 vanadium centres in the polyoxometallate.

15. A redox fuel cell according to claim 14 wherein at least one X is hydrogen.

16. A redox fuel cell according to claim 15 wherein X comprises at least one hydrogen and at least one other material selected from the group consisting of:

alkali metals, alkaline earth metals, ammonium and combinations of two or more thereof.

17. A redox fuel cell according to claim 14 wherein the polyoxometallate comprises H₃Na₂PMo₁₀V₂O₄₀.

18. A redox fuel cell according to claim 14, wherein the polyoxometallate comprises H₃Na₂PMo₉V₃O₄₀.

19. A redox fuel cell according to claim 14 wherein the polyoxometallate comprises H₃Na₄PMo₈V₄O₄₀.

20. A method of generating electricity by the redox fuel cell of claim 1, comprising

supplying the fuel to the anode region;

supplying the oxidant to the cathode region; and

generating electricity through the electrical circuit between the anode and the cathode.