Microbial fuel cell cathode assembly

• US 8,846,220 B2
• Filed: 10/16/2008
• Issued: 09/30/2014
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Irina Goryanin
• Original Assignee: Power Knowledge Limited
• Inventors: Fedorovich, Vyacheslav Viktorovich
• Primary Examiner(s): SMITH, JEREMIAH R
• Application Number:
  US12/738,547
• Publication Number:
  US 20100297477A1
• Time in Patent Office: 2,175 Days
• Field of Search: 429/2, 429/401, 429/512, 429/513, 429/515
• US Class Current: 429/2
• CPC Class Codes: H01M 8/04082 Arrangements for control of reactant parameters, e.g. pressure or concentration
• CPC Class Codes: H01M 8/04149 by diffusion, e.g. making use of membranes
• CPC Class Codes: H01M 8/04171 using adsorbents, wicks or hydrophilic material
• CPC Class Codes: H01M 8/04186 of liquid-charged or electrolyte-charged reactants
• CPC Class Codes: H01M 8/04201 Reactant storage and supply, e.g. means for feeding, pipes
• CPC Class Codes: H01M 8/04216 characterised by the choice for a specific material, e.g. carbon, hydride, absorbent
• CPC Class Codes: H01M 8/16 Biochemical fuel cells, i.e. cells in which microorganisms function as catalysts
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Disclosed is a microbial fuel cell cathode assembly comprising a catalyst (6) and an electrically conductive catholyte wicking member (5) having a catalyst contacting surface (5a) in contact with the catalyst, an electrical contact region (5c) for contacting an electrical connector, and a catholyte supply region (5b) for receiving catholyte from a catholyte supply (9), wherein the electrically conductive catholyte wicking member is operable to wick received catholyte from the catholyte supply region to form a film of catholyte on a part of the surface of the catalyst such that a part of the surface of the catalyst is in contact with both the film of catholyte and a part of the surface of the catalyst is in contact with a gas pathway arranged to supply oxygen to the catalyst.

Claims

1. A microbial fuel cell cathode assembly comprising:

a multilayer conductive porous substrate with macroporous and microporous structures inside coated by a catalyst, an electrically conductive catholyte wicking member, a catholyte-permeable rigid spacer with an ion-exchange membrane, an external catholyte supply reservoir, and a netlike foraminous member with a system of apertures;

wherein the wicking member contains no catalyst and is operable to wick the catalyst by catholyte received from a supply reservoir to form a film of the catholyte on a catalyst containing surface of the multilayer conductive porous substrate, wherein the spacer together with the foraminous member exert compressive forces on the multilayer conductive porous substrate and the catholyte wicking member, and wherein the microporous structure is defined by an internal porous structure of granules while the macroporous structure is defined by a space between individual granules which are pressed to each other by compressive forces thus determining gas pathways inside the multilayer conductive porous substrate with the catalyst.

2. The microbial fuel cell cathode assembly according to claim 1, wherein the conductive substrate is a compressed plurality of granules of activated carbon.

3. The microbial fuel cell cathode assembly according to claim 1, wherein a catholyte solvent comprises both water and a co-solvent which reduces surface tension of the catholyte.

4. The microbial fuel cell cathode assembly according to claim 1, wherein a catholyte-permeable spacer is provided between the catholyte wicking member and the ion-exchange membrane.

5. The microbial fuel cell cathode assembly according to claim 4, wherein the ion-exchange membrane, the catholyte-permeable spacer, and the catholyte wicking member are formed as three successive layers.

6. The microbial fuel cell cathode assembly according to claim 1, wherein an upper part of the wicking member comprises sections of two types, the first type of section being used for in electrical communication and the second type of section being used for liquid communication.

7. The microbial fuel cell cathode assembly according to claim 6, wherein a portion of the upper part of the wicking member serving for electric communication is in contact with an electrical connector for formation of an electrical circuit with the anodic zone.

8. The microbial fuel cell cathode assembly according to claim 1, wherein the catholyte wicking member comprises carbon cloth.

9. The microbial fuel cell cathode assembly according to claim 1, wherein the catholyte supply reservoir has direct liquid contact neither with an anodic zone nor with an electrolyte membrane which separates the anodic zone and a cathodic zone, and wherein the catholyte supply reservoir is located at some distance above a zone of electrochemical reaction at the catalyst.

10. The microbial fuel cell cathode assembly according to claim 1, wherein a portion of the upper part of wicking member serving for liquid communication is immersed in the catholyte supply reservoir, while a lower part of the wicking member is in contact with the catalyst.

11. The microbial fuel cell cathode assembly according to claim 9, wherein a portion of the upper part of wicking member serving for liquid communication is immersed in the catholyte supply reservoir, while a lower part of the wicking member is in contact with the catalyst.

12. The microbial fuel cell cathode assembly according to claim 9, wherein different levels of location of the catholyte supply reservoir and the catalyst enable continuous supply of the catalyst with a new portion of the catholyte through the wicking member by means of capillary effect enhanced by gravity.

13. The microbial fuel cell cathode assembly according to claim 10, wherein different levels of location of the catholyte supply reservoir and the catalyst enable continuous supply of the catalyst with a new portion of the catholyte through the wicking member by means of capillary effect enhanced by gravity.

14. The microbial fuel cell cathode assembly according to claim 11, wherein different levels of location of the catholyte supply reservoir and the catalyst enable continuous supply of the catalyst with a new portion of the catholyte through the wicking member by means of capillary effect enhanced by gravity.

15. The microbial fuel cell cathode assembly according to claim 1, wherein a size of the apertures in the foraminous member is such that compressed granules cannot pass there through, and wherein the size of the apertures in the foraminous member determines a size of the gas pathways to supply the reacting zone with air or oxygen.

16. The microbial fuel cell cathode assembly according to claim 2, wherein a size of the apertures in the foraminous member is such that compressed granules cannot pass there through, and wherein the size of the apertures in the foraminous member determines a size of the gas pathways to supply the reacting zone with air or oxygen.

17. The microbial fuel cell cathode assembly according to claim 4, wherein the ion-exchange membrane on a surface of the spacer is faced to an anodic zone.

18. The microbial fuel cell cathode assembly according to claim 1, wherein the catalyst comprises a coordinated compound.