High power density fuel cell comprising an array of microchannels
A phosphoric acid fuel cell according to one embodiment includes an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels; fuel electrodes formed along some of the microchannels; and air electrodes formed along other of the microchannels. A method of making a phosphoric acid fuel cell according to one embodiment includes etching an array of microchannels in a substrate, thereby forming walls between the microchannels; processing the walls to make the walls porous, thereby forming a porous electrolyte support structure; forming anode electrodes along some of the walls; forming cathode electrodes along other of the walls; and filling the porous electrolyte support structure with a phosphoric acid electrolyte. Additional embodiments are also disclosed.
1. A phosphoric acid fuel cell, comprising:
an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels;
fuel electrodes formed along some of the microchannels; and
air electrodes formed along other of the microchannels.
2. The phosphoric acid fuel cell as recited in claim 1 , further comprising a reforming catalyst inside the microchannels having the fuel electrodes.
3. The phosphoric acid fuel cell as recited in claim 2 , wherein the reforming catalyst is selected from a group consisting of platinum, carbon, copper, zinc, and alumina.
4. The phosphoric acid fuel cell as recited in claim 1 , wherein the porous electrolyte support structure comprise a material selected from a group consisting of silicon, a metal, glass, polymer, ceramic, plastic, epoxy resin, and a metal oxide.
5. The phosphoric acid fuel cell as recited in claim 1 , further comprising phosphoric acid electrolyte in the porous electrolyte support structure.
6. The phosphoric acid fuel cell as recited in claim 1 , wherein the microchannels are elongated and have longitudinal axes that are substantially parallel, wherein alternating microchannels have fuel and oxidant electrodes therein.
7. The phosphoric acid fuel cell as recited in claim 1 , further comprising metallic nanoparticles in the porous electrolyte support structure.
8. The phosphoric acid fuel cell as recited in claim 7 , wherein the nanoparticles comprise platinum.
9. The phosphoric acid fuel cell as recited in claim 1 , further comprising carbon nanostructures in pores of the porous electrolyte support structure.
10. The phosphoric acid fuel cell as recited in claim 1 , with the proviso that the cell contains no polymeric material.
11. The phosphoric acid fuel cell as recited in claim 1 , further comprising a phosphoric acid electrolyte in the porous electrolyte support structure; and a mechanism for causing reactants in immediately adjacent microchannels to flow in opposite directions for inducing counterflow heat exchange.
12. A fuel cell, comprising:
an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels;
fuel electrodes formed along some of the microchannels; and
air electrodes formed along other of the microchannels.
13. The fuel cell as recited in claim 12 , further comprising a reforming catalyst inside the microchannels having the fuel electrodes.
14. The fuel cell as recited in claim 12 , wherein the porous electrolyte support structure comprise a material selected from a group consisting of silicon, a metal, glass, polymer, ceramic, plastic, epoxy resin, and a metal oxide.
15. The fuel cell as recited in claim 12 , further comprising a proton-conducting or ion-conducting electrolyte in the porous electrolyte support structure.
16. The fuel cell as recited in claim 12 , wherein the microchannels are elongated and have longitudinal axes that are substantially parallel, wherein alternating microchannels have fuel and oxidant electrodes therein.
17. The fuel cell as recited in claim 12 , further comprising metallic nanoparticles in the porous electrolyte support structure.
18. The fuel cell as recited in claim 12 , further comprising carbon nanostructures in pores of the porous electrolyte support structure.
19. The fuel cell as recited in claim 12 , with the proviso that the cell contains no polymeric material.
20. The phosphoric acid fuel cell as recited in claim 1 , wherein one or more pores of the porous electrolyte support structure exhibit physical characteristics of being formed by a process selected from the group consisting of: anodic etching, electrochemical etching, chemical exchange and ion exchange.
21. The phosphoric acid fuel cell as recited in claim 1 , wherein the porous electrolyte support structure comprises a plurality of porous walls defining the array of microchannels, and
wherein each porous wall is adapted to store a fluidic electrolyte in a plurality of pores thereof.
22. The phosphoric acid fuel cell as recited in claim 21 , wherein each non-terminal porous wall is sandwiched between one of the fuel electrodes and one of the air electrodes.
23. The phosphoric acid fuel cell as recited in claim 1 , wherein the porous electrolyte support structure is adapted to wick an electrolyte into a plurality of pores of the porous electrolyte support structure.
24. The phosphoric acid fuel cell as recited in claim 1 , wherein the porous electrolyte support structure is functionalized to selectively wick an electrolyte of a first characteristic into a plurality of pores of the porous electrolyte support structure.
25. The phosphoric acid fuel cell as recited in claim 1 , wherein pores of the porous electrolyte support structure provide the electrodes access to an electrolyte.
26. The phosphoric acid fuel cell as recited in claim 1 , wherein the bottom and upper support layers are each non-porous, and
wherein the array of microchannels is a continuous, sealed array.
27. The phosphoric acid fuel cell as recited in claim 1 , wherein the porous electrolyte support structure is characterized as a three-dimensional lattice.
28. The phosphoric acid fuel cell as recited in claim 27 , wherein pores of the porous electrolyte support structure provide the electrodes access to an electrolyte.
29. The fuel cell as recited in claim 12 , wherein one or more pores of the porous electrolyte support structure exhibit physical characteristics of being formed by a process selected from the group consisting of: anodic etching, electrochemical etching, chemical exchange and ion exchange.
30. The fuel cell as recited in claim 12 , wherein the porous electrolyte support structure comprises a plurality of porous walls defining the array of microchannels, and
wherein each porous wall is adapted to store a fluidic electrolyte in a plurality of pores thereof.
31. The fuel cell as recited in claim 30 , wherein each non-terminal porous wall is sandwiched between one of the fuel electrodes and one of the air electrodes.
32. The fuel cell as recited in claim 12 , wherein the porous electrolyte support structure is adapted to wick an electrolyte into a plurality of pores of the porous electrolyte support structure.
33. The fuel cell as recited in claim 12 , wherein the porous electrolyte support structure is functionalized to selectively wick an electrolyte of a first characteristic into a plurality of pores of the porous electrolyte support structure.
34. The fuel cell as recited in claim 12 , wherein pores of the porous electrolyte support structure provides access for an electrolyte to the electrodes.
35. The fuel cell as recited in claim 12 , wherein the bottom and upper support layers are each non-porous, and
wherein the array of microchannels is a continuous, sealed array.
36. The fuel cell as recited in claim 12 , wherein the porous electrolyte support structure is characterized as a three-dimensional lattice.
37. The fuel cell as recited in claim 36 , wherein pores of the porous electrolyte support structure provide the electrodes access to an electrolyte.
38. A fuel cell, comprising:
an upper support layer;
a bottom support layer;
a porous electrolyte support structure comprising a plurality of porous walls extending between the bottom and upper support layers;
an array of microchannels defined by the porous electrolyte support structure;
a plurality of fuel electrodes formed along some of the microchannels;
a plurality of air electrodes formed along other of the microchannels;
a mechanism for causing reactants in immediately adjacent microchannels to flow in opposite directions for inducing counterflow heat exchange,
wherein the microchannels comprise fuel and oxidant microchannels, and
wherein the pores of the porous electrolyte support structure are configured to provide the electrodes access to a fluidic electrolyte.
39. The fuel cell as recited in claim 30 , further comprising:
a phosphoric acid electrolyte in a plurality of pores of the porous electrolyte support structure; and
a mechanism for causing reactants in immediately adjacent microchannels to flow in opposite directions for inducing counterflow heat exchange,
wherein one or more pores of the porous electrolyte support structure exhibit physical characteristics of being formed by a process selected from the group consisting of: anodic etching, electrochemical etching, chemical exchange and ion exchange,
wherein each non-terminal porous wall is sandwiched between one of the fuel electrodes and one of the air electrodes,
wherein the porous electrolyte support structure is functionalized to selectively wick an electrolyte of a first characteristic into a plurality of pores of the porous electrolyte support structure,
wherein the bottom and upper support layers are each non-porous,
wherein the array of microchannels is a continuous, sealed array,
wherein the porous electrolyte support structure is characterized as a three-dimensional lattice,
wherein pores of the porous electrolyte support structure provide the electrodes access to an electrolyte, and
wherein the pores of the porous electrolyte support structure provide the electrodes access to the phosphoric acid electrolyte.