EP1769554A2

EP1769554A2 - Method for making components for fuel cells and fuel cells made thereby

Info

Publication number: EP1769554A2
Application number: EP05750116A
Authority: EP
Inventors: Claudia c/o Dipartimento di Fisica RICCARDI; Paola c/o Dipartimento di Fisica ESENA; Stefano c/o Dipartimento di Fisica ZANINI; Paolo c/o Seal S.p.A. FRACAS; Silverio c/o Hysytec S.r.l. BERTINI; Massimiliano c/o Hysytec S.r.l. ANTONINI
Original assignee: HYSYTEC Srl; Seal SpA; Universita degli Studi di Milano Bicocca
Current assignee: Hysytec Srl; Universita degli Studi di Milano Bicocca; SAATI SpA
Priority date: 2004-05-24
Filing date: 2005-05-24
Publication date: 2007-04-04
Also published as: JP2008500706A; WO2005117176A2; WO2005117176A3; ITMI20041035A1

Abstract

A method for making components for fuel cells comprising at least a step of carrying out a surface treatment based on a plasma technology on at least one component of said fuel cell. To provide surface functional properties of different nature on materials used as fuel cell components, thereby allowing to make integrated component fuel cells of less weight and size, high efficiency and operating life.

Description

METHOD FOR MAKING COMPONENTS FOR FUEL CELLS AND FUEL CELLS MADE THEREBY BACKGROUND OF THE INVENTION The present invention relates to a method for making components for fuel cells and the fuel cells made thereby. As is known, fuel cells are generators suitable to directly and continuously transform a fuel chemical energy to electric energy or power. A polymeric membrane combustible cell conventionally comprises a negative electrode (anode) and a positive electrode (cathode) including a suitable catalyzer and arranged with a stacked relationship in a polymeric electrolyte. Hydrogen operates in these cells as a fuel and it supplies the anode, whereas oxygen or simply air enters the fuel cell or ^ΛΛFC" from the cathode side. More specifically, hydrogen atoms are split into protons and electrons which migrate toward the cathode through different paths, said protons migrating through the electrolyte and said electrons providing a continuous or direct- current which can supply an outer circuit. Near the cathode, said protons and electrons are recombined with oxygen to again provide water molecules. This reaction is facilitated by the provision of a catalyzer, i.e. a chemical substance speeding up the process, and intervening into the reaction without being consumed. Said catalyzer can also be suitably used for reducing the process temperature and auxiliary driving energy. From - a — chemical- ^• - energy - ^• to—electric^" energy^" transforming standpoint, the system can be nearly assimilated . to a battery, but it, however, is not subjected to discharges, and the reactor merely produces electric power due to the presence of fuel. Thus, the recharging time will be related to the time necessary for renewing fuel in its accumulating tanks, i.e. several minutes instead of hours which would be necessary for recharging an accumulator pack. Moreover, a transforming of chemical energy into electric energy, without combustion, provides and absolutely clean and not polluting process, since the single residue will consists of water steam. A lot of fuel cells exit, and, in particular the following: - phosphoric acid cells (PAFC) - alkaline electrolyte cells (AFC) - molten carbonate cells (MCFC) - solid oxide cells (SOFC) - proton exchange membrane cells (PEMFC) The polymer electrolyte fuel cells or PEM' s generate high density power with a high efficiency, thereby this technology would very useful both for stationary and dynamic or transport applications. In actual practice, weight, volume and cost represent the main factors which up to now have favored the use of such a technology. The PEMFC s differ from other types since they use a polymeric membrane as a cell electrolyte. Thus, being the membrane a polymeric film, problems related to sealing and assembling are less complex than in other types of cells: in fact, for example, the problem of managing dangerous liquids, corrosive acids included, does not exist. A PEMFC usually operates at low temperatures, in a 60 °C to 100 °C range, thereby providing a quick operation starting and a dynamic response to changes of the required power. Typical components of a PEM cell are the following: the proton exchange membrane; the electrically conductive arid porous support or gas diffusion layer; the catalytic support or electrode-catalyst layer arranged between the conductive porous layer and the membrane: the bipolar interconnector distributing oxygen and hydrogen to the reactive catalytic sites through conveying channels. Said gas diffusion layer, according to the status of the art, is made by arranging the polymeric membrane is arranged between two conductive porous sheets, i.e. the conventionally called "gas diffusion layer" or GDL. The function of these components is that of operating as gas (oxygen and hydrogen) diffusers, and providing a cell mechanical support and an electron electric path. Said GDL, also called "backing layer" is typically made of carbon materials, and can comprise a carbon filament or a non-woven fabric configuration including pressed carbon fibers or it can be merely made as a felt, and can be, moreover, impregnated with a water-repellent material, such as PTFE, which prevents water from entering the reacting gas diffusion volume as further necessary for a simultaneous back- diffusion of exhausted gases inside the porous - volume, to allow said gases to freely contact the catalyzer sides (ECL) . Moreover, PTFE allows water to be easily removed from the cathode, since it provides a non-wetted surface inside the material. Said catalyzer can be applied on said GDL, by also using a laminating process to be carried out on a surface thereof. The • chemical PTFE impregnating, however, does not provide an even surface distribution of the material, because it would block a portion of the holes thereby preventing an efficient control of the hydrophobic gradient inside said material. Moreover, such a chemical impregnation could modify the electric properties of the component. Thus, the above disclosed limitations would reduce the efficiency in controlling water in the cell, with a consequent less efficiency of the latter. Moreover, since the cell, is usually operated at a temperature less than 100 °C and at atmospheric pressure, water will be present in a liquid status, thereby a critical requirement would be that of holding the electrolytic water contents at a high value, to provide a high ion exchange. To hold a high water amount, in particular, would be particularly critical in a high current density operation (of approximatively 1 A/cm²) . A high water contents, on the other hand, would be assured by an optimum operation balance inside the cell. In this respect, a critical factor for providing an optimum water balance, is that of providing a highly efficient water withdrawing from the cathode side as well as water diffusing for moistening fuel at the anode side. Two scenarios can occur: the water transported through the electrolyte, from the anode to the cathode, is lost and the membrane is dehydrated, thereby decreasing the cell operating performance (frequently the amount of lost water would exceed that produced by the cathode) . This phenomenon is the so-called electric- osmotic transport phenomenon. To overcome this drawback, it is possible to suitably moisten the gases. The second phenomenon is that of an excessive water generation on the cathode due to the electro- osmotic transport phenomenon, and due to the oxygen and hydrogen into water combination reaction. The electrode is thus impregnated, thereby the efficiency will decrease. The reacting gas can evacuate said excess water contents if the gas flow increases. Thus, it is necessary to hold at a target value the mentioned optimum water balance to prevent said membrane from being dehydrated (an excessive amount of expelled water) or the reverse phenomenon of water saturating cathode (an insufficient amount of ejected water) ; in this respect said GDL will provide a basic function in optimizing the water and gas flows in its inside. To solve the above mentioned problems, it is necessary to provide a suitably controlled and optimized hydrophobic gradient between the two GDL surfaces, so as to assure a target evenness of the hydrophobic properties on each of the two surfaces and^' so that these modifications do not involve a changing of the thermomechanic properties and of the GDL free surface area. SUMMARY OF THE INVENTION Accordingly, ^' the aim of the present invention is to disclose a method for providing surface functional properties, of different nature, on materials used as components for fuel cells, thereby allowing to make integrated component fuel cells of less weight and size, and high efficiency and operating life. According to one aspect of the present invention, the above mentioned aim, as well as yet other objects, which will become more apparent hereinafter, are achieved by a method for making components for fuel cells, characterized in that said method comprises at least a step of carrying out a surface treatment, based on a plasma technology, on at least a said component. It is known that plasma treatments are susceptible to functionalize material surfaces both in a hydrophobic and in a hydrophilic sense, or provide deposits of different nature. The present invention just consists of applying this technology in the field of the fuel cells, for making components thereof. In particular, the method according to the present invention .provides, with respect to prior methods, the following advantages: it allows to make surfaces with novel specific properties, in a controlled manner, for applications in the fuel cell fields; said functional properties can be directly controlled during the functionalization process; said functional properties are even and permanent and do not modify mechanical properties and porosity of the material; said functional properties allow an integration of the fuel cell components; said properties provide a cell with a more efficient operation and a long operating life; the methods can be applied to materials having any desired geometry and to cells of any desired size and power; the thus processed material can be subjected to further desired processing methods, while preserving unaltered its novel properties and fitting the target characteristics of the cell components. The method allows moreover to reduce the amount of chemical agents used for functionalizing surfaces (catalyzer, water repellent material) - said method can be carried out with a low environmental impact; - the amount of the added chemical products is less than in conventional processes; in fact, the inventive method affects few surface layers at a molecular level (of the order from tenth of nanometers to a maximum of few microns) ; - an energy advantage: in fact, it is a dry process and, accordingly, it is not necessary to use water or consume power to evaporate water and/or other solvents; - an ecologic advantage: said method does not generate waste and emissions, allows the fibers to be recycled in an easier manner, since it uses a negligible amount of chemical additives and, moreover, it reduces the water- consume since, as stated, it is a dry process with a negligible water cycle. A. Preparing the GDL For functionalizing the GDL, it is possible to carry out a plasma treatment, according to the following three modes of operation: 1) A treatment for providing water repellent properties on both the surfaces, : e. to provide a hydrophobic gradient. 2) A treatment for providing hydrophilic properties on both the surfaces, i.e. to provide a hydrophilic gradient. 3) A treatment for providing the water repellent property on a face and the hydrophilic property of the other face. B. Preparing the catalytic support For the catalytic support or electrode-catalyst layer, it is possible to deposit a catalyzer deposit directly on the surface of the membrane or GDL, thereby directly integrating the deposit, so as to minimize the catalyzer amount, and provide an even catalyzer distribution suitable to increase the adhesion of the catalyzer on the surface. C . Preparing the interfaces To improve the interfaces and transport of charges and gases in the cell, there are used plasma treatments for increasing the surface area of the fuel cell components are moreover carried out. Thus to all the following cell components one can apply: The proton exchange membrane The electrically conductive and porous support or gas diffusion layer The catalytic support arranged between the electrically conductive-porous layer and the membrane or electrode catalyst layer The bipolar interconnector distributing or delivering through conveying channels oxygen and hydrogen to the reactive catalytic sites. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of the invention, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where: Figure 1 is a schematic view of the proton exchange membrane and related catalytic support or ECL deposited by a plasma depositing; Figure 2 is a schematic view showing the electrically conductive and porous support or GDL; Figure 3 is a further schematic view of the sequence of the components and of the surface treatment sites or locations, according to the present invention; Figure 4 is a schematic diagram showing the results of experimental tests obtained by unprocessed samples, samples processed by impregnating chemical products therein, and plasma processed samples. DESCRIPTION OF THE PREFERRED EMBODIMENTS 4. Preparing the GDL An application of the cold plasma according to the present invention consists of obtaining a water repellent gradient between the surfaces of the GDL. More specifically, to provide said water repellent properties, the plasma treatment can be carried out by using fluidized gases in general, such as fluorocarbons, for example- CF4, CFC, or NF3 and WF6, SFβ, silicon compounds, silane and siloxane, organosilanes such as hesamethyldisiloxane, hydrocarbons, styrene and mixtures thereof. It has been found that fluorocarbons and silicon compounds, silane and siloxanes can be so deposited as to form a film on the surfaces of the material adapted to provide a water repellent property or effect. These polymeric films have thicknesses varying from 0.1 nm to 10 microns. Moreover, to provide a good adhesion of the deposit, it is important to provide a stable and clean surface, i.e. a surface the degassing of which is suitably controlled and which is simultaneously activated. The treatment is carried out under vacuum conditions, P < 10 mbars, or at atmospheric pressure, with gas mixtures or pure gases as above mentioned. For an atmospheric pressure treatment, the samples are arranged at variable distances from the plasma generating source, typically at a distance from 1 mm to 50 mm. Then, said plasma is generated by using radiofrequency or microwave or low frequency sources. The power densities on the substrate surface are less than 1 W/cm². Treatment examples on a carbon fiber fabric sample and on a carbon fiber non-woven fabric are hereinbelow disclosed. The unprocessed sample, called "CC120/0", presents a contact angle of 30° as measured by the Wilhelmy measurement method. The Table ESI shows pairs of carbon fiber fabric which have been processed on a single side or surface A. The Table ES2 shows carbon fiber fabric pairs which have been processed on both sides or surfaces A and B. The Table ES3 shows the carbon fiber non woven fabric material pairs which have been processed on a single side or surface A. The atmospheric pressure treatments have been carried out by using SFβ and HDMSO mixtures. The power densities do no exceed 1 W/cm². The functional properties are even and permanent and do not modify the mechanical properties and porosity of the processed material. By suitable gradients, obtained by said plasma technology, the optimum water balance is so controlled as to allow the cell to operate with a greater efficiency and life. The better results are achieved by using a hydrophobic gradient between the two faces. With respect to an unprocessed GDL, the plasma functionalized GDL improves the operation of the fuel cell, which increases up to 50%. The power delivery, i.e. the cell constituted by plasma processed GDL, is up to 50% larger than that of a fuel cell the GDL of which has not been plasma processed, the other operating condition (hydrogen gas flow rate, cell temperature, air flow rate, moistening temperature) being the same. With respect to a GDL processed by conventional chemical methods, the plasma functionalized or processed GDL is susceptible to improve the fuel cell operating power performance by at least 25%. In other words, the power delivery of a fuel cell constituted by a plasma processed GDL, increases up to 25% with respect to that of a fuel cell constituted by a GDL processed by chemical methods or a commercial GDL. The plasma method allows to achieve a hydrophile gradient of the material, thereby providing surfaces with different contact angles susceptible to increases the hydrophilic properties of the starting sublayer or substrate. It is herein possible to use for the above mentioned method or process different types of plasmas such as noble gas plasma, inert gas plasma and, preferably, oxygen, air, chlorine, ammonia, fluorized gas, hydrogen, nitrogen, argon, helium, neon and mixture thereof, monomers and so on plasmas. If a vacuum generated plasma is used, the gas of which is air, then the material processing chamber is evacuated to provide a chamber pressure from 0.1 to 2 mbars . Thus, owing to the suitable gradients obtained by the disclosed plasma technology, it is possible to control the water optimum balance, so as to induce the cell to operate with a greater efficiency and life. Another plasma method or process consists of modifying the two surfaces of the material, respectively by a plasma hydrophilic and hydrophobic treatment, to optimize the cell water balance. 4. Preparing the catalytic support The catalyzer is directly deposited on the GDL or on the membrane of the cell by a vacuum depositing process, in which the catalyzer amount transferred to the surface is properly controlled. The catalyzer can be deposited both in powder form and in a vacuum sublimating phase, and by ion beams . C. Preparing the interfaces To improve and enhance the interfaces of each component (the catalyzer or support) , the mechanical and electric contact and the charged particle and gas flows, plasma processes are carried out in order to: 1. make the contacting surfaces homogeneous and even by plasma cleaning processes; 2. increase the contact surface area by plasma etching processes; 3. increase the adhesion of the deposited catalyzer, optionally also by other methods, by plasma surface activating processes. The Table ES4 shows the vacuum plasma treatments. The Table ES5 shows the atmospheric pressure plasma treatments. Method used for performing the plasma treatments The plasma treatments are performed by cold plasmas at^' pressures from 10^_1 mbars to 1 atm, and preferably from 10^_1 mbars to 10 mbars the plasma being a RF generated plasma and atmospheric pressure plasma. The used gases are noble and inert gases, oxygen, carbon dioxide, fluorine, containing gases, organosilane containing gases, siloxane, ammonia, styrene, hydrocarbons and mixtures thereof. The used powers are variable, but always less than 10 W/cm². The low pressure plasma process application times are less than 10 minutes, preferably from 30 seconds to 10 minutes, and more preferably from 1 minute to β minutes, and for high pressure plasmas they are less than 1 minute. Figure 1 is a schematic view showing the proton exchange membrane and the catalytic support or ECL deposited by the plasma process. Figure 2 is a schematic view showing the electrically conductive and porous support or GDL. Figure 3 is a schematic view showing the sequence of the components and locations of the surface treatments according to the present invention. The beneficial effects achieved by the treatments according to the present invention are briefly hereinbelow disclosed. Reduction of the component weight Experimental' data have confirmed that the provision of a controlled and even hydrophobic gradient on the surface allows to extend and increase the load curve range of MEA (V/1), i.e. it allows to increase, at high currents, the electric potential difference between the two electrodes. The advantage deriving from this properties consists of increasing the power generated at high currents for surface unit (A/cm²) . Accordingly, the generated power being the same, the size and weight of the fuel cell decrease. Increasing the cell efficiency Experimental data have confirmed that the provision of a controlled and even hydrophobic gradient on the surface allows to extend and broaden the range of the load curve of MEA (V/I) , i.e. it allows to increase, at high currents, the electric potential difference between the two electrodes. The advantage deriving from this property consists of an increase of the power generated at high currents, the fuel cell feeding gas flow rate being the same. Duration or life of the cell The functionalizing of the surface by a plasma processing or treatment consists of a modification of the surface for a nanometric size and such a modification is a permanent one. This involves a larger duration or useful life of the components and accordingly of the cell. Figure 4 is a schematic diagram in which are shown the results of experimental tests performed on unprocessed samples, samples processed by impregnating them with chemical products, and plasma processed samples. It has been found that the invention fully achieves the intended aim and objects. In fact, the inventive method provides functional properties to surfaces of different nature of materials used as components for fuel cells, thereby providing fuel cells with integrated components of less weight and size, greater efficiency and duration. In practicing the invention, the used materials, as well as the contingent size and shapes can be any, depending on requirements and the status of the art. Treatment examples on a carbon fiber fabric sample and on a non-woven carbon fiber fabric are hereinbelow shown. The unprocessed sample, called CC120/0, presents a contact angle of 30°, as measured by the Wilhelmy measurement method.

ESI - carbon fiber fabric pairs processed on a single side A

Residue P Gas Power Treatment Treated Contact P/gas time surface angle 3.6 10^Λ-6 SF6/ 70 1 minute CC120/6 140° bar 0.4 mbar I Side A

3.6 10^A-6 SFβ/ 70 1 minute II Side A Mbar 0.4 mbar CC120/10

2.6 10^Λ-5 HDMSO/ 60 4 minutes CC120/8 mbar 1 mbar I Side A

2.1 10^Λ-5 HDMSO/ 60W 4 minutes CC120/9 mbar 1 mbar II Side A

ES2 - carbon fiber fabric pairs processed on both sides A and B Residue P Gas Power Treatment Treated Contact P/gas time surface angle

2.6 10^Λ-5 HDMSO/ 60 W 4 minutes CC120/ 140^c mbar 1 mbar I Side A and B

2.6 10^Λ-5 HDMSO/ 60 W 4 minutes CC120/11 mbar 1 mbar II Side A and B

ES3 - non woven carbon fiber fabric pairs treated on a single side A

Residue P Gas/ Power Treatment Treated Contact P gas time surface angle

4.6 10^Λ-6 HDMSO/ 440 5 minutes felt 1/1 140° mbar 0.2 mbar I Side A

4.6 10^Λ-6 HDMSO/ 440 5 minutes felt 1/2 mbar 0.2 mbar II Side A 7.4 10^Λ-6 HDMSO/ 300 8 minutes felt 2/1 mbar 0.2 mbar I Side A

7.4 10^Λ-6 HDMSO/ 300 W 8 minutes felt 2/2 mbar 0.2 mbar II Side A

The atmospheric pressure treatments are carried out by using SFβ and HDMSO mixtures. The power densities do not exceed 1 W/cm². The functional properties are even and permanent and do not modify the mechanical properties and porosity of the material. By the suitable gradients achieved by the subject plasma technology, it is possible to control the water optimal balance thereby inducing the cell to operate with a greater efficiency and duration. Conclusions The best results in preparing the GDL are achieved by providing a hydrophobic gradient between the two faces or surfaces. With respect to an unprocessed GDL, the plasma functionalized or processed GDL improves the operation of the fuel cell, i.e. it increases by 50% the power delivery properties. The catalyzer is directly deposited on the GDL or on the membrane of the cell by a vacuum depositing process in which the catalyzer amount transferred to the surface is controlled. The catalyzer can be deposited both in powder form, in a vacuum sublimating phase, and by ion beams. To improve the interfaces of each component (the catalyzer or the support) , and consequently improve the mechanical and electric contact as well as the gas and charged particle transport, plasma processes are applied to: 1. make the contact surfaces homogeneous and even by plasma cleaning processes 2. increase the contact surface area by plasma etching processes 3. increase the adhesion of the deposited catalyzer, by possibly also using other methods, by plasma surface activating processes.

ES4 - treatments by plasma in vacuum

Residue P Gas Power Treatment Treated /Pgas time surface

< 10^Λ-4 air/ (0.1-0.4) (40-100) W (1-4) minutes film mbar mbar

ES5 - atmospheric pressure treatments

Speed Gas Power Treatment Treated Electrode number surface distance

(1-20) air 150-350 W (2÷10) film (0.5-5) mm m/minute The treatments are carried out by cold plasmas of variable pressure from 10^-1 mbars to 1 atm, and preferably from 10^"1 mbars to 10 mbars by RF generated plasmas and atmospheric pressure plasmas. The used gases are noble and inert gases, oxygen, carbon dioxide, fluorine containing gases, organosilane containing gases, siloxanes, ammonia, styrene, hydrocarbons, and mixtures thereof. The treatments are carried out by cold plasmas, at pressures varying from 10 mbars to 1 atm and preferably from^' 10^_1 mbars to 10 mbars by RF generated plasmas, and atmospheric pressure plasmas. The used gases are noble and inert gases, oxygen, carbon dioxide, fluorine holding gases, organosilane holding gases, siloxane, ammonia, styrene, hydrocarbons and mixtures thereof. Powers are variable, but always less than lOW/cm². The low pressure plasma process application times are less than 10 minutes, preferably from 30 seconds to 10 minutes, and more preferably from 1 minute to 6 minutes, whereas for high pressure plasmas the application time is less than 1 minute. Representation of the proton exchange membrane and the plasma deposited catalytic support or ECL.

Representation of the electrically conductive and porous support (GDL)

Surface being treated , ( O. ln - ljwn)

Re^presentation of the sequence of the components an_d treatment locations on the surface the patent is re_late_d to

The advantages achieved by the treatments according to the invention are hereinbelow disclosed. Reduction of the component weight Experimental data have confirmed that . the provision of a controlled and even hydrophobic gradient on the surface allows to extend and increase the load curve range of MEA (V/1), i.e. it allows to increase, at high currents, the electric potential difference between the two electrodes. The advantage deriving from this properties consists of an increase of the power generated at high currents for surface unit (A/cm²) . Accordingly, the generated power being the same, the size and weight of the fuel cell decrease.

Increase of the cell efficiency Experimental data have confirmed that the provision of a controlled and even hydrophobic gradient on the surface allows to extend and broaden the range of the load curve of MEA (V/I) , i.e. it allows to increase, at high currents, the electric potential difference between the two electrodes. The advantage deriving from this property consists of an increase of the power generated at high currents, the fuel cell feeding gas flow rate being the same.

Duration of the cell The functionalizing of the surface by a plasma processing or treatment consists of a modification of the surface for a nanometric size and such a modification is a permanent one. This involves a larger duration or useful life of the components and accordingly of the cell.

Representation of the experimental results Hereinbelow are shown the results of experimental tests achieved by unprocessed samples, samples processed by impregnating them with chemical products, and plasma processed samples. ^•

Art. 3: unprocessed fabric Art. 7 1501041: plasma treated fabric with a hydro- phobic gradient Art. 7 1501042: plasma treated fabric with a hydro- phobic surface without gradient 502041: fabric treated by impregnating in two sides 502044: fabric with other plasma treatment

Claims

CLAIMS 1. A method for making components for fuel cells, characterized in that said method comprises at least a step of carrying out a surface treatment based on a plasma technology on at least a component of a said fuel cell.

2. A method according to claim 1, characterized in that said method comprises a step of preparing two electrically conductive porous sheets (gas diffusion layer or GDL) .

3. A method according to claim 1 or 2, characterized in that said preparing step comprises a treatment for providing water repellent properties on two surfaces of said at least a component so as to provide a water repellent or hydrophobic gradient.

4. A method according to claim 1 or 2, characterized in that said preparing step comprises a treatment for providing a hydrophilic properties on said two surfaces, so as to provide a hydrophilic gradient.

5. A method according to claim 1 or 2, characterized in that said preparing step comprises a treatment for providing the water repellent property on a surface and the hydrophilic properties on the other surface.

6. A method according to one or more of the preceding claims, characterized in that said method comprises a catalytic support (Electrode-Catalyst-Layer) preparing step.

7. -A method according to one or more of the preceding claims, characterized in that said catalytic support preparing step comprises depositing a catalyzer directly on a surface of the membrane or GDL, thereby directly integrating the deposit, to minimize the catalyzer amount, and provide an ^"even distribution thereof, and increase its adhesion to the surface.

8. A method according to one or more of the preceding claims, characterized in that said method comprises a step of preparing interfaces, by using plasma treatments for increasing the surface area of the fuel cell components.

9. A method according to one or more of the preceding claims, characterized in that said step of preparing said interfaces provides to use plasma treatments for one or more of the following components: a proton exchange membrane; an electrically conductive and porous support or gas diffusion layer; a catalytic support arranged between the electrically conductive porous layer and said membrane (electrode catalyst layer) ; a bipolar interconnector distributing oxygen and hydrogen to reactive catalytic sites through conveying channels.

10. A method according to one or more of the preceding claims, characterized in that said method comprises the step of providing a water repellent gradient between the surfaces of said GDL by fluorized gases in general, such as fluorocarbons, for example CF4, CFC, or NF3 and WF6, SF6, silicon compounds, silane and siloxane, organosilanes such as hesamethyldisiloxane, hydrocarbons, styrene and mixtures thereof.

11. A method according to one or more of the preceding claims, characterized in that said fluorocarbons and silicon compounds, silane and siloxanes are so deposited as to form a film on the surfaces of the materials, adapted to provide a water repellent effect.

12. A method according to one or -more of the preceding claims, characterized in that said polymeric films have a thickness variable 0.1 nm to 10 microns.

13. A method according to one or more of the preceding claims, characterized in that said treatment is carried out under vacuum conditions (P < 10 mbars) or at atmospheric pressure by gas mixtures or pure gases.

14. A method according to one or more of the preceding claims, characterized in that, for an atmospheric pressure treatment, said components are arranged at variable distances from a plasma generating source, said variable distances being typically from 1 mm to 50 mm.

15. A method according to claim 14, characterized in that said method comprises a step of generating vacuum up to a minimum pressure of 10-6 mbars, said plasma being generated by radiofrequency or microwave or low frequency sources.

16. A method according to one or more of the preceding claims, characterized in that the power densities on the substrate layer are less than 1 W/cm².

17. A method according to one or more of the preceding claims, characterized in that said atmospheric pressure treatments are carried out by SF6 and HDMSO mixtures, the power densities do not exceeding 1 W/cm².

18. A method according to one or more of the preceding claims, characterized in that in said method different type of plasmas such as noble gas plasmas, inert gas plasmas and preferably oxygen, air, chlorine, ammonia, fluorized gas, hydrogen, nitrogen, argon, helium, neon and mixtures thereof, monomer plasmas are used.

19. A method according to one or more of the preceding claims, characterized" in that, as a vacuum generated plasma is used, the gas of which is air, the material processing chamber is. evacuated to provide a vacuum pressure from 0.1 to 2 mbars.

20. A method according to one or more of the preceding claims, characterized in that said method comprises a^' step of modifying the two surfaces of said at least a component respectively by a plasma hydrophilic treatment and a plasma hydrophobic treatment, to optimize the cell water balance.

21. A method according to one or more of the preceding claims, characterized in that, in preparing said catalytic support, the catalyzer is directly deposited on said GDL or on said membrane of said cell, by a vacuum depositing process, in which the catalyzer amount transferred to the surface is controlled.

22. A method according to one or more of the preceding claims, characterized in that said catalyzer is deposited both in powder form, vacuum sublimating phase and by ion beams.

23. A method according to one or more of the preceding claims, characterized in that said plasma treatments are carried out by cold plasmas having pressures variable from 10^"1 mbars to 1 atm and preferably from 10^"1 mbars to 10 mbars by RF generated plasmas and atmospheric pressure plasmas.

24. A method according to one or more of the preceding claims, characterized in that said gases are noble and inert gases, oxygen, carbon dioxyde, fluorine containing gases, organosilane containing gases, siloxane, ammonia, styrene, hydrocarbons and mixtures thereof.

25. A method according to one or more of the preceding claims, characterized in that said power is variable but preferably less than 10 W/cm².

26. A method according to one or more of the preceding claims, characterized in that for a low pressure plasma process an application time is less than 10 minutes, preferably from 30 seconds to 10 minutes, and more preferably from 1 minute to 6 minutes, whereas for an atmospheric pressure plasma, said time is less than 1 minute.

27. A fuel cell, characterized in that one or more of the components of said fuel cell comprises a surface treatment based on the plasma technology.

28. A method according to one or more of the preceding claims, characterized in that said method comprises one or more of the disclosed and/or illustrated characteristics.

29. A fuel cell according to one or more of the preceding claims, characterized in that said fuel cell comprises one or more of the disclosed and/or illustrated characteristics.