WO2017066949A1

WO2017066949A1 - Fuel cell electrode material and apparatuses

Info

Publication number: WO2017066949A1
Application number: PCT/CN2015/092499
Authority: WO
Inventors: Kechuang Lin; Yi-Jui Huang
Original assignee: Kechuang Lin; Yi-Jui Huang
Priority date: 2015-10-22
Filing date: 2015-10-22
Publication date: 2017-04-27
Also published as: KR102039536B1; KR20180003536A; CN109618561A; JP2018522365A; TW201715778A; JP6726210B2; TWI650897B; CN109618561B

Abstract

A fuel cell electrode material is disclosed herein, which comprises a plurality of pores having a substantially uniform size of about 500 nm–5 mm, with a variation of < 20％, having a porosity of about 40-85％. This fuel cell electrode material may be used in a catalyst layer, a gas fusion layer, or a water disposal layer in a fuel cell apparatus. Fuel cell apparatuses comprising such fine-array porous fuel cell electrode materials with different designs, and methods of manufacturing such fine-array porous fuel cell electrode material are also disclosed herein.

Description

FUEL CELL ELECTRODE MATERIAL AND APPARATUSES

BACKGROUND

Fuel cells are a type of electrochemical device that converts the chemical energy from a fuel, including hydrogen and a hydrocarbon, such as diesel and methanol, into electricity through a chemical reaction with an oxidizing agent such as oxygen or hydrogen peroxide. Due to its high energy efficiency and its capability to produce electricity continuously so long as the fuel is supplied, a fuel cell has a wide range of applications, including transportation, material handling, stationary, portable, and emergency backup power applications.

A fuel cell typically requires the presence of catalyst layers at its anode and cathode electrode assemblies to lower the activation energy required for the chemical reaction from which electricity is generated. The catalyst layer is conventionally designed to have finely dispersed crystallites of a precious metal catalyst, such as platinum, on a conductive carrier that has a high surface area, such as carbon papers, carbon cloth, and carbon nanotubes, in order to increase both the active surface area and the electrocatalytic activity of the catalyst. Such a configuration, however, usually has issues such as high cost and lack of reliability, which has greatly limited the practical application of fuel cells.

SUMMARY

The present disclosure relates to a fuel cell electrode material for use in fuel cell apparatuses, and specifically to a fine-array porous fuel cell electrode material, and additionally relates to the application of the fuel cell electrode material in fuel cell apparatuses.

Disclosed herein provides a fuel cell electrode material for use in a fuel cell apparatus. The fuel cell electrode material typically comprises a fine-array porous material having a plurality of pores, wherein the plurality of pores have a size of about 500 nm-5 mm, and preferably of 1000-50000 nm； the size of the plurality of pores is substantially uniform with a variation of less than about 20％； and the fine-array porous material has a porosity of about 40-85％. In some embodiments, the fine-array porous material may be composed of a metal, such as Ni, Al, Cu, Au, Ag, Ti, Fe, Pt, Pd, Ru, Mn, Co, and Cr. In some embodiments, the fine-array porous material may be composed of an alloy, such as stainless steel, Pt-Co, Pt-Fe, Pt-Cr, Pt-Ni, Pt-Ti, Pt-Mn, Pt-Cu, Pt-V, Pt-Cr-Co, Pt-Fe-Cr, Pt-Fe-Mn, Pt-Fe-Co, Pt-Fe-Ni, Pt-Fe-Cu, Pt-Cr-Cu, Pt-Co-Ga. In some embodiments, the fine-array porous material may be composed of a metal oxide, selected from a group consisting of CoTMPP-TiO₂, MnO_x-CoTMPP, CoFe₂O₄, Pt-WO₃, Pt-TiO₂, Pt-Cu-MO_x, MnO₂, CrO₂, Cu_xMn_yO_z, LaMnO₃ and La1-xSr_xFeO₃.

In some embodiments, a fuel cell electrode material may be used in the anode or cathode catalyst layer, and typically comprises a fine-array porous material having a porosity of about 74％. In some embodiments, the fine-array porous material is composed substantially wholly of a catalytic material: such as a metal (e.g. Ru, Pd, Ni, Al, Cu, Au, Ag, Ti, Fe, Pt, Mn, Co, and Cr) , an alloy (e.g. Pt-base alloy such as Pt-Co, Pt-Fe, Pt-Cr, Pt-Ni, Pt-Ti, Pt-Mn, Pt-Cu, Pt-V, Pt-Cr-Co, Pt-Fe-Cr, Pt-Fe-Mn, Pt-Fe-Co, Pt-Fe-Ni, Pt-Fe-Cu, Pt-Cr-Cu, Pt-Co-Ga) , or a metal oxide (e.g. CoTMPP-TiO₂, MnO_x-CoTMPP, CoFe₂O₄, Pt-WO₃, Pt-TiO₂, Pt-Cu-MOxMnO₂, CrO₂, Cu_xMn_yO_z, LaMnO₃ and La1-xSr_xFeO₃) . In some other embodiments, the fine-array porous material may comprise a catalyst carrier, made of a cost-effective metal (e.g. Ni, Al, Cu, Fe, Ti, Cr, Mn, Co, Zn) , a conductive ceramic (e.g. ZnO, Cu₂O, ITO, AZO, IZO, IGZO) or a conductive polymer (e.g. polypyrrole, polyphenylene sulfide, phthalocyanine, polyaniline, and polythiophene) , and a catalyst component, comprising at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP or CoFe₂O₄. In some embodiments, the catalyst component may be coated on the surface of the catalyst carrier. Yet in some other embodiments, particles of the catalyst component may be disposed within the plurality of pores of the fine-array porous catalyst carrier. Yet in some other embodiments, the particles of catalyst component may be attached on the surface of particles of a second catalyst carrier, such as carbon nanotubes or carbon nanospheres, and they together are disposed within the plurality of pores of the fine-array porous catalyst carrier.

In some embodiments, a fuel cell electrode material may be used in the water disposal layer at the anode or cathode, and is typically surface-treated, for example, by oxidation of the metal composition, or by coating with a hydrophilic material, at a designated region of the fine-array porous fuel cell electrode material to become hydrophilic. Hydrophilic surface treatment of the water disposal layer electrode material may be achieved by coating the electrode material with a hydrophilic plasma in some embodiments, by treating the electrode material with a surfactant (e.g. ammonium lauryl sulfate, sodium lauryl sulfate (SDS) , dioctyl sodium sulfosuccinate, perfluorooctanesulfonate (PFOS) , perfluorobutanesulfonate, sodium lauroyl sarcosinate, perfluorononanoate or perfluorooctanoate) in some other embodiments, or by chemically modifying the electrode material with a chemical having hydrophilic functional groups such as hydroxyl (-OH) group or carboxyl (-COOH) group in yet some other embodiments.

In some embodiments, a fuel cell electrode material may be used in the gas diffusion layer at the anode or cathode, and is typically surface-treated, for example, by coating with a hydrophobic material, at a designated region to become hydrophobic. Hydrophobic surface treatment of the gas diffusion layer electrode material may be achieved by coating the electrode material with a hydrophobic plasma in some embodiments, by treating the electrode material with fluorosilicones, siloxanes, or fluorocarbons in some other embodiments.

Disclosed herein also provides a fuel cell apparatus that applies the fine-array porous fuel cell electrode material as disclosed above. The fuel cell apparatus includes a membrane electrolyte assembly (MEA) , which comprises a polymer electrolyte membrane (PEM) , an anode catalyst layer and a cathode catalyst layer, wherein the polymer electrolyte membrane (PEM) is sandwiched between the anode layer and the cathode layer； at least one of the anode catalyst layer and the cathode catalyst layer comprises a fine-array porous fuel cell electrode material having a porosity of about 74％, and a catalyst.

In some embodiments of the fuel cell apparatus, the fuel cell electrode material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Fe, Ti, Cr, Mn, Co, and Zn； and the catalyst is at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP or CoFe₂O₄. In some embodiments, the catalyst is coated evenly on surface of the fine-array porous material； in some other embodiments, particles of the catalyst are disposed within the plurality of pores of the fine-array porous material； yet in some other embodiments, at least one of the anode catalyst layer and the cathode catalyst layer further comprise a catalyst carrier, such as carbon nanotubes or carbon nanospheres, wherein particles of the catalyst carrier carrying particles of the catalyst particles on outer surface of the particles of the catalyst carrier are disposed within the plurality of pores of the fine-array porous material in the at least one of the anode catalyst layer and the cathode catalyst layer.

In some embodiments, the fuel cell apparatus comprises a combined catalyst-gas diffusion layer design. In these embodiments, at least one of the anode catalyst layer and the cathode catalyst layer is further configured to allow the reactive gases to diffuse through. In some embodiments, the anode catalyst layer, the cathode catalyst layer, or both, is further surface-treated at a designated region to be hydrophobic to facilitate the reactive gases to diffuse through. In some embodiments, the fuel cell apparatus may comprise a separate catalyst-gas diffusion layer design. In these embodiments, the fuel cell apparatus further comprises an anode gas diffusion layer and a cathode gas diffusion layer, wherein the anode gas diffusion layer and the cathode gas diffusion layer are respectively arranged on a flanking side of the anode catalyst layer and the cathode catalyst layer opposing the polymer electrolyte membrane (PEM) ； and at least one of the anode gas diffusion layer and the cathode gas diffusion layer comprises a second fine-array fuel cell electrode material as disclosed above. In some embodiments, the pore size of the second fine-array porous fuel cell electrode material in the at least one of anode gas diffusion layer and the cathode gas diffusion layer is smaller than the pore size of the fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer； and the at least one of the anode gas diffusion layer and the cathode gas diffusion layer further comprises a second catalyst, selected from at least one of Ru or Pd.

In some embodiments, the fuel cell apparatus further comprises a water disposal layer, arranged on bottom of the anode gas diffusion layer, the anode catalyst layer, the cathode catalyst layer and the cathode gas diffusion layer, wherein the water disposal layer comprises a third fine-array porous fuel cell electrode material as disclosed above, wherein the pore size of the third fine-array porous fuel cell electrode material in the water disposal layer is bigger than the pore size of the fine-array porous fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer, and is bigger than the pore size of the second fine-array porous fuel cell electrode material in the at least one of the anode gas diffusion layer and the cathode gas diffusion layer； and the third fine-array porous fuel cell electrode material in the water disposal layer is optionally surface-treated to become hydrophilic. In some embodiments, the fuel cell apparatus further comprises an anode water disposal layer and a cathode water disposal layer, wherein the anode water disposal layer and the cathode water disposal layer are arranged between the anode catalyst layer and the polymer electrolyte membrane, and between the cathode catalyst layer and the polymer electrolyte membrane, respectively； at least one of the anode water disposal layer and the cathode water disposal layer comprises a second fine-array porous fuel cell electrode material, and the pore size of the second fine-array porous fuel cell electrode material is bigger than the pore size of the fine-array porous fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer； and the anode catalyst layer and the cathode catalyst layer are configured to allow the reactive gases to diffuse through.

In some embodiments, the fuel cell apparatus comprises a membrane electrolyte assembly (MEA) , wherein the membrane electrolyte assembly comprises, in an order from anode to cathode, an anode gas diffusion layer, an anode catalyst layer, a polymer electrolyte membrane (PEM) and a cathode catalyst layer, wherein at least one of the anode gas diffusion layer and the cathode gas diffusion layer comprises a fine-array porous fuel cell electrode material. In some embodiments of the fuel cell apparatus, at least one of the anode catalyst layer and the cathode catalyst layer comprises a catalyst carrier, selected from carbon nanotubes or carbon nanospheres.

Disclosed herein also provides methods of manufacturing a fine-array porous fuel cell electrode material as disclosed above, comprising the step of (i) manufacturing the fine-array porous material by 3D printing or by a template fabrication approach. In some embodiments of the methods, the fine-array porous material may be manufactured by 3D printing. In some other embodiments, the fine-array porous material may be manufactured by a template fabrication approach, comprising the sub-steps of: a) electrophoretically fabricating a colloidal particle template； b) infiltrating the colloidal particle template with an electrode material； and c) removing the colloidal particle template. In some of the embodiments, sub-step (b) is achieved by at least one of electrodeposition, PVD (Physical Vapor Deposition) , CVD (Chemical Vapor Deposition) , or Sol-Gel (sol-gel process) .

In some embodiments, the methods further comprise the step of: (ii) manufacturing, on top of the fine-array porous material, a second fine-array porous material by 3D printing or by a template fabrication approach. In some of the embodiments, the second fine-array porous material in step (ii) is configured to have a pore size bigger than the pore size of the fine-array porous material, and the second fine-array porous material is configured to have hydrophilic surface. The second fine-array porous material may be composed of a hydrophilic conductive polymer in some embodiments, or may be surface-treated to become hydrophilic in some other embodiments. In one example, the second fine-array porous material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Fe, Ti, Cr, Mn, Co, and Zn, and surface of the second fine-array porous material is treated by oxidation. In another example, the second fine-array porous material may be coated with a hydrophilic material.

In some embodiments, the method may further comprise the step of (ii) distributing particles of a catalyst carrier that carry particles of a catalyst on surface of, or into the plurality of pores in the fine-array porous material. The catalyst carrier may be carbon nanotubes or carbon nanospheres. In some embodiments, the method may further comprise, immediately following step (ii) , the step of (iii) binding the particles of the catalyst with the fine-array porous material in the fuel cell electrode material, which may be achieved by heating in some of the embodiments.

In some embodiments, the method may further comprise the step of (ii) applying an anti-erosion treatment to the fine-array porous material. For example, if the fine-array porous material is composed of a metal, such as Zn, Ti and Ni, the anti-erosion treatment in step (ii) may be oxidation treatment in some embodiments, and may be surface-coating with an anti-erosive material in in some other embodiments.

The fine-array porous fuel cell electrode material as disclosed herein may also be applied in other types of fuel cell apparatuses such as SOFC (solid oxide fuel cell) , DMFC (direct methanol fuel cell) , PAFC (phosphoric acid fuel cell) , FC, MCFC (molten carbonate fuel cell) , or PFC. Disclosed herein also provide a fuel cell apparatus, comprising a fine-array porous fuel cell electrode material, wherein the fuel cell apparatus is at least one of SOFC (solid oxide fuel cell) , DMFC (direct methanol fuel cell) , PAFC (phosphoric acid fuel cell) , FC, MCFC (molten carbonate fuel cell) , or PFC.

Compared with conventional fuel cell electrode materials, such as carbon paper/cloth/nanotubes coated with catalyst particles, a fine-array porous fuel cell electrode material disclosed herein has the following advantages. First, it has a much higher effective electrocatalytical area due to the significantly higher surface-area-to-volume ratio of the fine-array porous structure. Second, its membrane structure eliminates the issue of gradual loss of reliability due to the falling off of the catalyst particles from the conductive carrier of a conventional fuel cell. Third, it eliminates the use of binders to tightly attach the catalyst particles to the conductive carrier in a conventional fuel cell, dramatically reducing the amount of catalyst used and the cost incurred in the manufacturing of fuel cells, and greatly elevating the reliability. Fourth, designs having a less expensive metal or compound of metal oxide (e.g. Cu, Fe, Al, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP, CoFe₂O₄ etc. ) forming a fine-array porous conductive carrier which is coated with expensive noble metal catalysts (e.g. Pt) may further reduce the manufacturing cost of fuel cells, and can achieve a higher conductivity than the conventionally used carbon paper/cloth/nanotubes/nanospheres. Fifth, the presence of periodic structure of a fine-array porous fuel cell electrode material eliminates the issue of heat buildup at some spots due to the local defects or the uneven distribution of catalyst particles on carbon-based conductive carriers. Sixth, the presence of periodic structure of a fine-array porous fuel cell electrode material further allows efficient distribution and transfer of the reactive gases or reactive solvent (e.g. H₂, O₂, ethanol, methanol) , liquid waste product (e.g. H₂O) , and electrons across/through the material. Lastly, some designs can achieve a combination of catalyst layers and gas diffusion layers in the fuel cell, which could simplify the design, reduce the cost, and increase the reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a conventional proton exchange membrane fuel cell (PEMFC) apparatus having catalytic layers made of carbon nanotubes coated with finely dispersed catalyst particles.

FIG. 2 illustrates a fuel cell membrane electrode assembly comprising fine-array porous electrode materials according to some embodiments of this disclosure.

FIG. 3 illustrates a fuel cell membrane electrode assembly comprising fine-array porous electrode materials according to some embodiments of this disclosure.

FIG. 4 illustrates fuel cell membrane electrode assembly comprising fine-array porous electrode materials according to some embodiments of this disclosure.

FIG. 5 illustrates fuel cell membrane electrode assemblies comprising fine-array porous electrode materials according to some embodiments of this disclosure.

FIG. 6 illustrates another membrane electrode assembly comprising fine-array porous electrode materials according to some embodiments of this disclosure.

DETAILED DESCRIPTION THE DRAWINGS

FIG. 1 illustrates a conventional proton exchange membrane fuel cell (PEMFC) apparatus having catalytic layers made of carbon nanotubes coated with finely dispersed catalyst particles. The PEMFC apparatus 100 comprises, in the order from anode to cathode, an anode endplate 101, an anode bipolar plate 102, an anode gasket 103, an anode gas diffusion layer 104, a membrane electrode assembly (MEA) 105, a cathode gas diffusion layer 106, a cathode gasket 107, a cathode bipolar plate 108, and a cathode endplate 109. Gas channels are typically arranged in both the anode bipolar plate 102 and the cathode bipolar plate 108, serving as pathways to feed H₂ and O₂ into the anode and cathode of the fuel cell, respectively. Due to limited view, Figure 1 only illustrates the O₂ gas channel 110 in the cathode bipolar plate 108. The MEA 105 typically comprises a polymer electrolyte membrane (PEM) 111, sandwiched between an anode catalyst layer 112 and a cathode catalyst layer 113. Typically both the anode catalyst layer and the cathode catalyst layer comprise a catalyst carrier, coated with very fine powders of an anode catalyst and a cathode catalyst, respectively. The catalyst carrier typically is composed of a carbon paper, a carbon cloth, or a film of carbon nanotubes； the anode catalyst may be composed of a metal, such as Pt, an alloy, such as Pt-Ru, a metal oxide, such as Cerium (IV) oxide, a metal sulfide, such as Mo_x Ru_y S_z and Mo_x Rh_y S_z, or a chalcogenide such as (Ru_1-x Mo_x ) SeO_z； and the cathode catalyst may be composed of Pt or Ni. Figure 1 also shows a picture of a typical anode catalyst layer, which comprises a film of carbon nanotubes 114, coated with nanoparticles of Pt 115.

A conventional fuel cell as illustrated in Figure 1 has the following weaknesses. First, a binder is usually required for the stable attachment and effective dispersing of the catalyst particles on the surface of the conductive carrier. Yet the presence of a binder decreases the effective electrocatalytical area of the catalyst in the fuel cell, and thus to compensate for this reduction, a greater amount of catalyst is needed for a given level of power output. Second, catalyst particles coated on the surface of the conductive carrier may easily get loose and fall off from the carrier in a vibrating/shocking environment, or even during feeding of gases into, or disposal of water/other reaction products from, the fuel cell. This creates a reliability issue on the fuel cells.

FIG. 2 illustrates a fuel cell membrane electrode assembly (MEA) comprising fine-array porous electrode materials according to some embodiments of this disclosure. As shown in FIG. 2, the membrane electrode assembly (MEA) 200 comprises a polymer electrolyte membrane (PEM) 201, which is sandwiched between an anode catalyst layer 202 and a cathode catalyst layer 203. The anode catalyst layer 202 and the cathode catalyst layer 203 may both comprise a fuel cell electrode material having a fine-array porous structure 204. This fuel cell electrode material 204 typically comprises a fine-array porous material having a plurality of pores, wherein the plurality of pores have a pore size of about 500 nm–5 mm； the size of the plurality of pores is substantially uniform with a variation of less than about 20％； and the fine-array porous material has a porosity of about 40-85％. In some preferred embodiments, a fuel cell electrode material may comprise a highly compact fine-array porous material, having a porosity of about 74％, which is theoretically the highest surface-area-to-volume ratio for a porous material.

In some embodiments, as illustrated in 205, a fine-array porous material may be wholly composed of Pt or some other fuel cell catalyst materials, and thus can be directly used as a catalytic layer material in a MEA in a fuel cell. In some other embodiments, a fine-array porous carrier, composed of a metal/alloy, such as Cu, Al, Fe, Ni, and stainless steel, or of a conductive metal-oxide, such as Zn_xO_1-x, may be evenly coated on its surface with a fuel cell catalyst material, such as Pt, also illustrated in 205. In some other embodiments, a fine-array porous material may serve as a high surface-area conductive carrier to carry particles of catalysts in the catalyst layers of a fuel cell. In some other embodiments, as illustrated in 206, a fine-array porous carrier, composed of a metal/alloy such as Cu, Al, Fe, stainless steel, and Ni, or of a conductive metal-oxide, such as Zn_xO_1-x may be coated within its pores with nanoparticles of a fuel cell catalyst such as Pt. In yet some other embodiments, as illustrated in 207, a second conductive carrier, such as carbon nanotubes, grapheme, and carbon nanospheres, along with the catalyst particles which the second conductive carrier carries on its surface, are disposed within the pores of a first fine-array porous conductive carrier, composed of Cu, Al, Fe, stainless steel, or Ni, or of a conductive metal-oxide, such as Zn_xO_1-x.

Because of the presence of periodic pores in the fine-array porous structure, the fuel cell electrode material as disclosed above may also be used as a gas diffusion layer material, allowing the reactive gases, such as H₂ and O₂, to be evenly and efficiently diffused through the pores of the fine-array porous structure, while at the same time the presence of catalyst on the surface of, or within the pores of, the fine-array porous conductive carrier allows effective catalytic reactions to occur in the fuel cell. These features allow the design of a single combined catalyst-gas diffusion layer in a fuel cell apparatus, which functions both as a catalyst layer and as a gas diffusion layer in the fuel cell. This combined catalyst-gas diffusion layer with fine-array porous structure can greatly simplify the modular designing and manufacturing of fuel cells. It addition, with designs to treat specific regions of the fine-array porous fuel cell electrode material to become hydrophobic/hydrophilic, it is also possible to facilitate the disposal of final reaction product, such as water, from these designated regions of the fine-array porous fuel cell electrode material of the fuel cell. FIG. 3 illustrates a fuel cell membrane electrode assembly (MEA) comprising fine-array porous electrode materials according to some embodiments of this disclosure. The fuel cell membrane electrode assembly 300 comprises a polymer electrolyte membrane (PEM) 301, a combined anode catalyst-gas diffusion layer 302, a combined cathode catalyst-gas diffusion layer 303 and a water disposal layer 304, wherein the PEM 301 is sandwiched between the combined anode catalyst-gas diffusion layer 302 and the combined cathode catalyst-gas diffusion layer 303, the water disposal layer 304 is arranged at bottom of the PEM 301, the combined anode catalyst-gas diffusion layer 302, and the combined cathode catalyst-gas diffusion layer 303. The combined anode catalyst-gas diffusion layer 302 and the combined cathode catalyst-gas diffusion layer 303 both comprise a fine-array porous fuel cell electrode material, composed wholly of an anode catalyst or a cathode catalyst, or alternatively comprising a fine-array porous metallic carrier coated with, or infiltrated with, particles of an anode or cathode catalyst with or without a second catalyst carrier, as illustrated in 205, 206 and 207 in FIG. 2. Besides the function as catalyst layers, the combined anode catalyst-gas diffusion layer 302 and the combined cathode catalyst-gas diffusion layer 303 also serve a role of gas diffusion layers in the fuel cell membrane electrode assembly (MEA) . Optionally, the combined anode catalyst-gas diffusion layer 302 and the combined cathode catalyst-gas diffusion layer 303 may be surface-treated to increase the hydrophobicity of certain regions located within both layers in order to further increase the gas diffusion efficiency of the layers in the fuel cell. The water disposal layer 304 also comprises a fine-array porous material and is designed for disposal of the final reaction product, such as water, from inside the fuel cell, and is optionally surface-treated to increase the hydrophilicity in order to further increase the water disposal efficiency.

FIG. 4 illustrates fuel cell membrane electrode assembly (MEA) comprising fine-array porous electrode materials according to some embodiments of this disclosure. As illustrated in FIG. 4A, the fuel cell membrane electrode assembly (MEA) 400 comprises the components of an anode gas diffusion layer 401, an anode catalyst layer 402, a polymer electrolyte membrane (PEM) 403, a cathode catalyst layer 404, and a cathode gas diffusion layer 405, arranged in the order from anode to cathode. In some embodiments, the anode catalyst layer 402 and the cathode catalyst layer 404 may both comprise fine-array porous fuel cell electrode materials as disclosed in FIG. 2 (205, 206 and 207) , comprising anode catalyst and cathode catalyst respectively, whereas the anode gas diffusion layer 401 and the cathode gas diffusion layer 405 may comprise a gas diffusion material that does not have a fine-array porous structure. Yet in some other embodiments, the anode gas diffusion layer 401 and the cathode gas diffusion layer 405 may both comprise fine-array porous electrode materials, whereas the anode catalyst layer 402 and the cathode catalyst layer 404 may comprise a conventional catalyst layer material that does not have a fine-array porous structure, such as a carbon paper, carbon cloth, or carbon nanotubes coated with anode and cathode catalysts, respectively. Yet in some other embodiments, the anode catalyst layer 402, the cathode catalyst layer 404, the anode gas diffusion layer 401, and the cathode gas diffusion layer 405 may all comprise fine-array porous fuel cell electrode materials, yet with different pore sizes or compositions. Yet in some embodiments, the anode catalyst layer 402 and the anode gas diffusion layer 401, or the cathode catalyst layer 404 and the cathode gas diffusion layer 405 may comprise a whole chunk of fine-array porous fuel cell electrode material with a uniform pore size, which is coated with, or infiltrated with, particles of an anode/cathode catalyst with or without a second catalyst carrier, at the part immediately next to the polymer electrolyte membrane (PEM) 403, to form the anode/cathode catalyst layer 402/404； whereas the part without catalyst components form the anode/cathode gas diffusion layer 401/405. In some embodiments, the fuel cell membrane electrode assembly (MEA) may further comprise an extra anode/cathode catalyst layer between the polymer electrolyte membrane (PEM) 403 and the anode/cathode catalyst layer 402/404. In one example, as illustrated in FIG. 4C, a conventional carbon-derived catalyst layer 423, comprising a carbon paper/cloth/nanotubes coated with an anode/cathode catalyst, is arranged on one side of the fine-array porous catalyst layer 422, which comprises particles of carbon carriers carrying anode/cathode catalyst particles within the pores, whereas the fine-array porous gas diffusion layer 421 is arranged on the other side of the fine-array porous catalyst layer 422.

In one embodiment as illustrated in FIG. 4B, the fuel cell membrane electrode assembly (MEA) 410 comprises, in the order from anode to cathode, an anode gas diffusion layer 411, an anode catalyst layer 412, a polymer electrolyte membrane (PEM) 413, a cathode catalyst layer 414, and a cathode gas diffusion layer 415, wherein the anode catalyst layer 412 and the cathode catalyst layer 414 both comprise fine-array porous fuel cell electrode material comprising the Pt catalyst； the anode gas diffusion layer 411 and the cathode gas diffusion layer 415 both comprise a fine-array porous fuel cell electrode material, which has a smaller pore size than that of the fine-array porous fuel cell electrode material used in the anode and cathode catalyst layers 412 and 414 and is coated with the Ru/Pd catalyst. With this configuration, the anode and cathode gas diffusion layers 411 and 415 not only provide diffusion pathways allowing the reactive gases such as H₂ and O₂ to react on the surface of the anode and cathode catalyst layers 412 and 414 of the fuel cell, but also serve as an filtering layer removing the carbon monoxide from the reactive gases by the presence of Ru/Pd, preventing carbon monoxide existed in the reactive gases from poisoning the Pt catalyst in the anode and cathode catalyst layers 412 and 414.

FIG. 5 illustrates a fuel cell membrane electrode assembly comprising fine-array porous electrode materials according to some embodiments of this disclosure. As illustrated in FIG. 5A, the fuel cell membrane electrode assembly (MEA) 500 comprises the components of an anode gas diffusion layer 501, an anode catalyst layer 502, a polymer electrolyte membrane (PEM) 503, a cathode catalyst layer 504, and a cathode gas diffusion layer 505, arranged in the order from anode to cathode, and also comprises a water disposal layer 506, arranged at the bottom of the above mentioned MEA components 501-505. The compositions and structures of the MEA components 501-505 are similar to the MEA components 401-405 in the fuel cell MEA as illustrated in FIG. 4A. The water disposal layer 506 comprises a fine-array porous material with a pore size about 0.5-100 times the pore size of the anode gas diffusion layer 501 and the cathode gas diffusion layer 505, and is designed for disposal of the final liquid reaction product, such as water, from inside the fuel cell, and is optionally surface-treated to have increased hydrophilicity on the surface in order to further increase the disposal efficiency.

In another embodiment, as illustrated in FIG. 5B, the fuel cell membrane electrode assembly (MEA) 510 comprises the components of an anode combined catalyst-gas diffusion layer 511, an anode water disposal layer 512, a polymer electrolyte membrane (PEM) 513, a cathode water disposal layer 514, and a cathode combined catalyst-gas diffusion layer 515, arranged in the order from anode to cathode. The anode combined catalyst-gas diffusion layer 511 and the cathode combined catalyst-gas diffusion layer 515 both comprise fine-array porous fuel cell electrode materials as illustrated in FIG. 3, which have smaller pore sizes and are coated with anode and cathode catalysts respectively. They serve both as catalyst layers and gas diffusion layers in the fuel cell. The anode water disposal layer 512 and the cathode water disposal layer 514 both comprise fine-array porous materials , and are designed for disposal of the final liquid reaction product, such as water, from inside the fuel cell. The fine-array porous materials in the anode water disposal layer 512 and the cathode water disposal layer 514 may optionally have a larger, or alternatively and preferably smaller, pore size than the fine-array porous fuel cell electrode materials in the anode combined catalyst-gas diffusion layer 511 and the cathode combined catalyst-gas diffusion layer 515. The anode and cathode

water disposal layer

512 and 514 may be optionally surface-treated to have increased hydrophilicity on the surface to increase the efficiency of water disposal； alternatively and preferably they may be surface-treated to have increased hydrophobicity on the surface to keep water off the anode/cathode combined catalyst-

gas diffusion layer

511 and 515, allowing efficient flow of reactive gases to effectively contact with catalysts in the anode/cathode combined catalyst-

gas diffusion layer

511 and 515.

FIG. 6 illustrates a fuel cell membrane electrode assembly comprising fine-array porous electrode material according to some embodiments of this disclosure. The fuel cell membrane electrode assembly (MEA) 600 comprises the components of an anode gas diffusion layer 601, an anode catalyst layer 602, a polymer electrolyte membrane (PEM) 603, a cathode catalyst layer 604, and a cathode gas diffusion layer 605, arranged in the order from anode to cathode. The anode catalyst layer 602 and the cathode catalyst layer 604 both comprise a catalyst carrier, such as a carbon paper, a carbon cloth, a film of carbon nanotubes, or a film of carbon nanospheres, coated with anode catalysts and cathode catalysts respectively. The anode gas diffusion layer 601 and the cathode gas diffusion layer 605 both comprise a fine-array porous material, which is optionally surface-treated to increase the hydrophobicity of the surfaces of the layers in order to increase the gas diffusion efficiency of the layers in the fuel cell.

In some embodiments of a fuel cell apparatus comprising a fine-array porous fuel cell electrode material, regardless of it being employed in a catalyst layer, a gas diffusion layer or a water disposal layer, the fine-array porous fuel cell electrode material may be surface-treated by oxidation on part or whole of the electrode material to prevent the erosion of acid and alkaline existing in, or produced from the electrochemical reactions occurring in, the fuel cell apparatus.

Although specific embodiments have been described above in detail, the description is merely for purposes of illustration. It should be appreciated, therefore, that many aspects described above are not intended as required or essential elements unless explicitly stated otherwise. Various modifications of, and equivalent acts corresponding to, the disclosed aspects of the exemplary embodiments, in addition to those described above, can be made by a person of ordinary skill in the art, having the benefit of the present disclosure, without departing from the spirit and scope of the disclosure defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures.

Claims

A fuel cell electrode material for use in a fuel cell apparatus, comprising a fine-array porous material, wherein:

the fine-array porous material comprises a plurality of pores, wherein the plurality of pores have a pore size of about 500 nm –5 mm；

the size of the plurality of pores is substantially uniform with a variation of less than about 20％； and

the fine-array porous material has a porosity of about 40-85％.
The fuel cell electrode material according to Claim 1, wherein the fine-array porous material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Au, Ag, Ti, Fe, Pt, Pd, Ru, Mn, Co and Cr, an alloy, selected from a group consisting of stainless steel, Pt-Co, Pt-Fe, Pt-Cr, Pt-Ni, Pt-Ti, Pt-Mn, Pt-Cu, Pt-V, Pt-Cr-Co, Pt-Fe-Cr, Pt-Fe-Mn, Pt-Fe-Co, Pt-Fe-Ni, Pt-Fe-Cu, Pt-Cr-Cu and Pt-Co-Ga, or a metal oxide, selected from a group consisting of CoTMPP-TiO₂, MnO_x-CoTMPP, CoFe₂O₄, Pt-WO₃, Pt-TiO₂, Pt-Cu-MO_x, MnO₂, CrO₂, Cu_xMn_yO_z, LaMnO₃ and La1-xSr_xFeO₃.
The fuel cell electrode material according to Claim 1, wherein the pore size of the plurality of pores of the fine-array porous material is about 1000-50000 nm.
The fuel cell electrode material according to Claim 3, wherein the fine-array porous material has a porosity of about 74％.
The fuel cell electrode material according to Claim 4, wherein the fine-array porous material is composed substantially of Ru, Pd, Ni, Al, Cu, Au, Ag, Ti, Fe, Pt, stainless steel, Mn, Co, and Cr, or Pt-base alloy, Pt-Co, Pt-Fe, Pt-Cr, Pt-Ni, Pt-Ti, Pt-Mn, Pt-Cu, Pt-V, Pt-Cr-Co, Pt-Fe-Cr, Pt-Fe-Mn, Pt-Fe-Co, Pt-Fe-Ni, Pt-Fe-Cu, Pt-Cr-Cu, Pt-Co-Ga, or a metal oxide, selected from a group consisting of CoTMPP-TiO₂, MnO_x-CoTMPP, CoFe₂O₄, Pt-WO₃, Pt-TiO₂, Pt-Cu-MOxMnO₂, CrO₂, Cu_xMn_yO_z, LaMnO₃ and La1-xSr_xFeO₃.
The fuel cell electrode material according to Claim 4, wherein the fine-array porous material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Fe, Ti, Cr, Mn, Co and Zn, a conductive ceramic, selected from a group consisting of ZnO, Cu₂O, ITO, AZO, IZO and IGZO, or a conductive polymer, selected from a group consisting of polypyrrole, polyphenylene sulfide, phthalocyanine, polyaniline and polythiophene.
The fuel cell electrode material according to Claim 6, wherein the fine-array porous material is coated with at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP or CoFe₂O₄.
The fuel cell electrode material according to Claim 6, further comprising catalyst particles composed of at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnOx-CoTMPP and CoFe₂O₄, wherein the catalyst particles are disposed within the plurality of pores of the fine-array porous material.
The fuel cell electrode material according to Claim 6, further comprising catalyst carrier particles and catalyst particles, wherein the catalyst particles are disposed on surface of the catalyst carrier particles； and the catalyst carrier particles carrying the catalyst particles are disposed within the plurality of pores of the fine-array porous material.
The fuel cell electrode material according to Claim 9, wherein the catalyst carrier comprises at least one of carbon nanotubes, grapheme or carbon nanospheres.
The fuel cell electrode material according to Claim 10, wherein the catalyst particles are composed of at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP or CoFe₂O₄.
The fuel cell electrode material according to Claim 1, wherein the fine-array porous material is surface-treated at a designated region to become hydrophilic.
The fuel cell electrode material according to Claim 12, wherein the fine-array porous material is surface-treated by oxidation, coated with a hydrophilic plasma, treated with a surfactant, or modified with a chemical having at least one hydrophilic functional group, on surface of the fuel cell electrode material.
The fuel cell electrode material according to Claim 1, wherein the fine-array porous material is surface-treated at a designated region to become hydrophobic.
A fuel cell apparatus, comprising a membrane electrolyte assembly (MEA) , wherein the membrane electrolyte assembly comprises a polymer electrolyte membrane (PEM) , an anode catalyst layer and a cathode catalyst layer, wherein:

the polymer electrolyte membrane (PEM) is sandwiched between the anode layer and the cathode layer；

at least one of the anode catalyst layer and the cathode catalyst layer comprises a fuel cell electrode material according to Claim 4 and a catalyst.
The fuel cell apparatus according to Claim 15, wherein the fine-array porous material in the fuel cell electrode material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Fe, Ti, Cr, Mn, Co, and Zn； and the catalyst is at least one of Pt, Ru, Pd, CoPc, CoTMPP-TiO₂, MnO_x-CoTMPP or CoFe₂O₄.
The fuel cell apparatus according to Claim 16, wherein the catalyst is coated evenly on surface of the fine-array porous material.
The fuel cell apparatus according to Claim 16, wherein particles of the catalyst are disposed within the plurality of pores of the fine-array porous material.
The fuel cell apparatus according to Claim 16, wherein at least one of the anode catalyst layer and the cathode catalyst layer further comprise a catalyst carrier, selected from at least one of carbon nanotubes, graphene or carbon nanospheres, wherein particles of the catalyst carrier carrying particles of the catalyst particles on outer surface of the particles of the catalyst carrier are disposed within the plurality of pores of the fine-array porous material in the at least one of the anode catalyst layer and the cathode catalyst layer.
The fuel cell apparatus according to Claim 15, wherein at least one of the anode catalyst layer and the cathode catalyst layer is further configured to allow the reactive gases to diffuse therethrough.
The fuel cell apparatus according to Claim 20, wherein the at least one of the anode catalyst layer and the cathode catalyst layer is surface-treated at a designated region to be hydrophobic to facilitate the reactive gases to diffuse therethrough.
The fuel cell apparatus according to Claim 15, further comprising an anode gas diffusion layer and a cathode gas diffusion layer, wherein:

the anode gas diffusion layer and the cathode gas diffusion layer are respectively arranged on a flanking side of the anode catalyst layer and the cathode catalyst layer opposing the polymer electrolyte membrane (PEM) ； and

at least one of the anode gas diffusion layer and the cathode gas diffusion layer comprises a second fuel cell electrode material according to Claim 1.
The fuel cell apparatus according to Claim 22, wherein

the pore size of the second fuel cell electrode material in the at least one of anode gas diffusion layer and the cathode gas diffusion layer is smaller than the pore size of the fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer； and

the at least one of the anode gas diffusion layer and the cathode gas diffusion layer further comprises a second catalyst, selected from at least one of Ru or Pd.
The fuel cell apparatus according to Claim 22, further comprising a water disposal layer, arranged on bottom of the anode gas diffusion layer, the anode catalyst layer, the cathode catalyst layer and the cathode gas diffusion layer, wherein:

the water disposal layer comprises a third fuel cell electrode material according to Claim 1, wherein:

the pore size of the third fuel cell electrode material in the water disposal layer is bigger than the pore size of the fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer, and is bigger than the pore size of the second fuel cell electrode material in the at least one of the anode gas diffusion layer and the cathode gas diffusion layer； and

the third fuel cell electrode material in the water disposal layer is optionally surface-treated to become hydrophilic.
The fuel cell apparatus according to Claim 15, further comprising an anode water disposal layer and a cathode water disposal layer, wherein:

the anode water disposal layer and the cathode water disposal layer are arranged between the anode catalyst layer and the polymer electrolyte membrane, and between the cathode catalyst layer and the polymer electrolyte membrane, respectively；

at least one of the anode water disposal layer and the cathode water disposal layer comprises a second fuel cell electrode material according to Claim 1, and the pore size of the second fuel cell electrode material is bigger than the pore size of the fuel cell electrode material in the at least one of the anode catalyst layer and the cathode catalyst layer； and

the anode catalyst layer and the cathode catalyst layer are configured to allow the reactive gases to diffuse therethrough.
A fuel cell apparatus according to Claim 15, comprising a membrane electrolyte assembly (MEA) , wherein the membrane electrolyte assembly comprises, in an order from anode to cathode, an anode gas diffusion layer, an anode catalyst layer, a polymer electrolyte membrane (PEM) and a cathode catalyst layer, wherein:

at least one of the anode gas diffusion layer and the cathode gas diffusion layer comprises a fuel cell electrode material according to Claim 1.
The fuel cell apparatus according to Claim 26, wherein at least one of the anode catalyst layer and the cathode catalyst layer comprises a catalyst carrier, selected from carbon nanotubes or carbon nanospheres.
A method of manufacturing a fuel cell electrode material as of Claim 1, comprising the step of:

(i) manufacturing the fine-array porous material by 3D printing, or by a template fabrication approach, wherein the template fabrication approach comprises the sub-steps of:

a) electrophoretically fabricating a colloidal particle template；

b) infiltrating the colloidal particle template with an electrode material ； and

c) removing the colloidal particle template.
The method according to claim 28, wherein in the template fabrication approach, sub-step (b) is achieved by at least one of electrodeposition, PVD (Physical Vapor Deposition) , CVD (Chemical Vapor Deposition) , or Sol-Gel (sol-gel process) .
The method of manufacturing a fuel cell electrode material according to Claim 28, further comprising, immediately following step (i) , the step of:

(ii) manufacturing, on top of the fine-array porous material, a second fine-array porous material by 3D printing or by a template fabrication approach.
The method according to Claim 30, wherein in step (ii) the second fine-array porous material is configured to have a pore size bigger than the pore size of the fine-array porous material, and the second fine-array porous material is configured to have hydrophilic surface.
The method according to Claim 31, wherein in step (ii) the second fine-array porous material is composed of a hydrophilic conductive polymer.
The method according to Claim 31, wherein in step (ii) the second fine-array porous material is surface-treated to become hydrophilic.
The method according to Claim 33, wherein in step (ii) the second fine-array porous material is composed of a metal, selected from a group consisting of Ni, Al, Cu, Fe, Ti, Cr, Mn, Co, and Zn, and surface of the second fine-array porous material is treated by oxidation.
The method according to Claim 33, wherein in step (ii) the second fine-array porous material is coated with a hydrophilic material.
The method of manufacturing a fuel cell electrode material according to Claim 28, further comprising, immediately following step (i) , the step of:

(ii) distributing particles of a catalyst carrier that carry particles of a catalyst on surface of, or into the plurality of pores in the fine-array porous material.
The method of manufacturing a fuel cell electrode material according to Claim 36, wherein the catalyst carrier is selected from at least one of carbon nanotubes or carbon nanospheres.
The method according to Claim 37, further comprising, immediately following step (ii) , the step of,

(iii) binding the particles of the catalyst with the fine-array porous material in the fuel cell electrode material.
The method according to Claim 38, wherein the step (iii) is achieved by heating.
The method according to Claim 28, further comprising, immediately following step (i) , the step of:

(ii) applying an anti-erosion treatment to the fine-array porous material.
The method according to Claim 40, wherein in step (i) the fine-array porous material is composed of a metal, selected from a group consisting of Zn, Ti and Ni； and in step (ii) the anti-erosion treatment is oxidation treatment.
The method according to Claim 40, wherein in step (i) the fine-array porous material is composed of a metal, selected from a group consisting of Zn, Ti and Ni； and in step (ii) the anti-erosion treatment is surface-coating with an anti-erosive material.
A fuel cell apparatus, comprising a fuel cell electrode material according to Claim 1, wherein the fuel cell apparatus is at least one of SOFC (solid oxide fuel cell) , DMFC (direct methanol fuel cell) , PAFC (phosphoric acid fuel cell) , FC, MCFC (molten carbonate fuel cell) , or PFC.
The fuel cell electrode material according to Claim 13, wherein the fine-array porous material is surface-treated by treating with a surfactant on the surface of the fuel cell electrode material, wherein the surfactant is at least one of ammonium lauryl sulfate, sodium lauryl sulfate (SDS) , dioctyl sodium sulfosuccinate, perfluorooctanesulfonate (PFOS) , perfluorobutanesulfonate, sodium lauroyl sarcosinate, perfluorononanoate or perfluorooctanoate.
The fuel cell electrode material according to Claim 13, wherein the fine-array porous material is surface-treated by modifying with a chemical having at least one hydrophilic functional group on the surface of the fuel cell electrode material, wherein the hydrophilic functional group is hydroxyl (-OH) group or carboxyl (-COOH) group.
The fuel cell electrode material according to Claim 14, wherein the fine-array porous material is surface-treated by coating with a hydrophobic plasma or by treating with at least one of a fluorosilicone, a siloxane, or a fluorocarbon, on the surface of the fuel cell electrode material.