Composite electrode comprising a carbon structure coated with a thin film of mixed metal oxides for electrochemical energy storage

• US 20090185327A1
• Filed: 01/17/2008
• Published: 07/23/2009
• Est. Priority Date: 01/17/2008
• Status: Active Grant

• Current Assignee: Fraser Wade Seymour
• Original Assignee: Fraser Wade Seymour
• Inventors: Seymour, Fraser Wade
• Granted Patent: US 7,986,509 B2
• Time in Patent Office: Days
• US Class Current: 361/500
• CPC Class Codes: H01G 11/26 characterised by their structure, e.g. multi-layered, porosity or surface features
• CPC Class Codes: H01G 11/32 Carbon-based
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: H01G 11/46 Metal oxides
• CPC Class Codes: H01G 9/0029 Processes of manufacture
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/48 of inorganic oxides or hydroxides
• CPC Class Codes: H01M 4/50 of manganese
• CPC Class Codes: H01M 4/52 of nickel, cobalt or iron
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A composite electrode is created by forming a thin conformal coating of mixed metal oxides on a highly porous carbon structure. The highly porous carbon structure performs a role in the synthesis of the mixed oxide coating and in providing a three-dimensional, electronically conductive substrate supporting the thin coating of mixed metal oxides. The metal oxide mixture shall include two or more metal oxides. The composite electrode, a process for producing said composite electrode, an electrochemical capacitor and an electrochemical secondary (rechargeable) battery using said composite electrode are disclosed.

Claims

1. ) A composite electrode comprising a porous carbon structure with a conformal surface coating of mixed metal oxides.

2. ) The composite of claim 1 wherein said metal oxide coating mixture shall comprise two or more metal oxides selected from a group consisting of oxides of manganese, nickel, cobalt, iron, aluminum, chromium, molybdenum, rhodium, iridium, osmium, rhenium, vanadium, tungsten, tantalum, palladium, lead, tin and titanium.

3. ) The composite of claim 1 wherein said metal oxide coating mixture shall comprise of oxides of manganese and nickel.

4. ) The composite of claim 1 wherein said metal oxide coating mixture is composed of a nanocrystalline phase, a polycrystalline phase, an amorphous phase or any combination thereof.

5. ) The composite of claim 1 wherein the average thickness of said metal oxide coating is greater than 10 nanometers and less than 1000 nanometers.

6. ) The composite of claim 1 wherein the porous carbon structure is selected from a group of three-dimensional structures consisting of carbon aerogel nanofoam, aligned carbon nanofiber structure, unaligned carbon nanofiber structure, aligned carbon nanotube structure, unaligned carbon nanotube structure, carbon xerogel/ambigel structure, templated porous carbon film, porous pre-formed carbon powder film or any combination thereof.

7. ) The composite of claim 1 wherein said porous carbon structure possesses pores with an average diameter larger than 5 nanometers and smaller than 5 micrometers.

8. ) The composite of claim 1 wherein pores of said porous carbon structure which are larger than the average pore size of said porous carbon structure are generally not occluded by said metal oxide coating.

13. ) A capacitor cell comprising an electrolyte, an electronically insulating but ionically conductive separator film, a pair of electrodes separated by said separator and electrolyte, each electrode physically attached and electronically connected to a current collector, wherein at least one of said electrodes comprise the composite electrode comprising a porous carbon structure with a conformal surface coating of mixed metal oxides according to any one of claims 1 to 8.

14. ) The capacitor cell of claim 13 wherein the electrolyte comprises a non-aqueous solution, an aqueous solution or polymer containing derivatives of alkali metals including but not limited to hydroxides, sulfates and chlorides of said alkali metals or any combination thereof.

15. ) The capacitor cell of claim 13 wherein the current collector is selected from a group consisting of metal foil, metal mesh, electrically conductive polymer composites and expanded metal.

16. ) The capacitor cell of claim 13 wherein the second of two electrodes, if not a composite electrode as defined in claim 13, is selected from a group consisting of a metal oxide;

a metal carbide;

a metal nitride;

a composite carbonaceous paste comprising activated carbon powder, binder and conductivity enhancing carbon or a porous carbon structure.

17. ) A secondary battery cell comprising an electrolyte, an electronically insulating but ionically conductive separator film, a pair of electrodes separated by said separator and electrolyte, each electrode physically attached and electronically connected to a current collector, wherein at least one of said electrodes comprise the composite electrode comprising a porous carbon structure with a conformal surface coating of mixed metal oxides according to any one of claims 1 to 8.

18. ) The secondary battery cell of claim 17 wherein the electrolyte comprises a non-aqueous solution, an aqueous solution or polymer containing derivatives of alkali metals including but not limited to hydroxides, sulfates and chlorides of said alkali metals or any combination thereof.

19. ) The secondary battery cell of claim 17 wherein the current collector is selected from a group consisting of metal foil, metal mesh, electrically conductive polymer composites and expanded metal.

20. ) The secondary battery cell of claim 17 wherein the second of two electrodes, if not a composite electrode as defined in claim 17, is selected from a group consisting of a metal oxide;

a metal carbide;

a metal nitride;

a composite carbonaceous paste comprising graphite powder, binder and conductivity enhancing carbon or a porous carbon structure.

9. ) A method for producing a composite electrode comprising a porous carbon structure with a conformal surface coating of mixed metal oxides wherein said coating is produced by an oxidation/reduction reaction occurring between the metal salt contained in an aqueous precursor solution and the surface of said porous carbon structure when said porous carbon structure is infiltrated with said precursor solution which is reduced on the surface of the carbon and co-deposited in oxide form upon the carbon.

10. ) The method for producing the composite electrode of claim 9 wherein said infiltration is accomplished by immersion of said carbon structure in a bath of said aqueous metal salt precursor solution or by application of pressure spray consisting of said aqueous metal salt precursor solution upon said carbon structure.

11. ) The method for producing the composite electrode of claim 9 wherein said aqueous metal salt precursor solution shall comprise two or more salts of metals selected from a group consisting of manganese, nickel, cobalt, iron, aluminum, chromium, molybdenum, rhodium, iridium, osmium, rhenium, vanadium, tungsten, tantalum, palladium, lead, tin and titanium.

12. ) The method for producing the composite electrode of claim 9 wherein said aqueous metal salt precursor solution shall comprise a pH buffer, Ni(NO.sub.3).sub.2 6H.sub.2O and one of NaMnO.sub.4, KMnO.sub.4 or LiMnO.sub.4.