EP1838903A2 - Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte - Google Patents

Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte

Info

Publication number
EP1838903A2
EP1838903A2 EP05850580A EP05850580A EP1838903A2 EP 1838903 A2 EP1838903 A2 EP 1838903A2 EP 05850580 A EP05850580 A EP 05850580A EP 05850580 A EP05850580 A EP 05850580A EP 1838903 A2 EP1838903 A2 EP 1838903A2
Authority
EP
European Patent Office
Prior art keywords
current
voltage
polymer
process according
metal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP05850580A
Other languages
German (de)
French (fr)
Other versions
EP1838903B1 (en
Inventor
Pierre Millet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Universite Paris Sud Paris 11
Areva H2Gen SAS
Original Assignee
Compagnie Europeenne des Technologies de lHydrogene SA
Universite Paris Sud Paris 11
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Compagnie Europeenne des Technologies de lHydrogene SA, Universite Paris Sud Paris 11 filed Critical Compagnie Europeenne des Technologies de lHydrogene SA
Publication of EP1838903A2 publication Critical patent/EP1838903A2/en
Application granted granted Critical
Publication of EP1838903B1 publication Critical patent/EP1838903B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/54—Electroplating of non-metallic surfaces
    • C25D5/56—Electroplating of non-metallic surfaces of plastics
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/615—Microstructure of the layers, e.g. mixed structure
    • C25D5/617—Crystalline layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
    • C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/18—Electroplating using modulated, pulsed or reversing current
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers

Definitions

  • the present invention relates to a process for electroplating a metal to obtain solid polymer electrolyte-electrolyte cells. It applies more particularly, but not exclusively, to the preparation of electrolysers, the electrolysis of water in particular for the supply of fuel cell gas or the regeneration of used cells in situ.
  • the solid polymer electrolyte-electrolyte cells comprise a solid polymer electrolyte or an ion exchange membrane whose thickness is small (approximately 200 ⁇ m) bearing metal deposits on its two opposite faces which serve as electrodes, one being a cathode and the other anode.
  • the membranes sometimes consist of perfluorosulfonic polymer forming a network of fixed cations and further comprising mobile or labile anions within this network, for example FLEMION® membranes of the company ASAHI. They are used in chlor-alkali electrolysis.
  • the membranes consist in principle of perfluorosulfonic polymer forming a fixed anion network and further comprising mobile or labile cations within this network.
  • NAFION ® membranes developed by the company Dupont de Nemours in wherein the anions are SO 3 "ions and the cations can be of various natures. Na +, K +, Li +, however, tends to favor the use of protons H + for the ionic conductivity of the membrane and thus its yield are better.
  • the electrolysis of water can be carried out using such cells by feeding the anode in pure water: an oxygen evolution takes place there while the protons produced by the electrolysis cross the membrane in the direction of the cathode. There is therefore permanent circulation of protons inside the membrane. Hydrogen is released near the cathode.
  • metal catalysts are used in the form of deposits on the faces of the membrane.
  • the polymer membranes are then very acidic and require the use of expensive noble metals such as platinum, iridium, ruthenium, gold, rhodium or palladium. It is therefore important to try to optimize the ratio of the amount of metal used / energy efficiency, in particular by making metal deposits on the one hand, of small thickness so as not to hinder the path of the products involved in electrolysis and, on the other hand, porous and rough, that is to say having a maximum exchange surface for a minimum location in order to increase the reactivity of the electrode, ie a high active surface area ratio.
  • the properties (thickness, porosity, roughness) of such a metal deposit originate from a phenomenon relating to the growth of metal deposits, for example of noble metal, on a surface of a different nature. Indeed, it turns out that this phenomenon is due to the fact that the energy necessary for the formation of a nucleus is higher than the energy necessary for the growth of an existing nucleus. Thus, rather than forming a regular monolayer on the whole surface and then stacking the monolayers, we first observe a growth in isolated islands called nuclei. Then, a deposition continues to grow from nuclei in dendritic growth.
  • WO 00/28114 discloses a proton exchange membrane fuel cell gas diffusion electrode made by electroplating a nanocrystalline catalytic metal onto a substrate. This result is obtained by putting in contact an electrically conductive substrate and a counter electrode with an electroplating bath containing ions of a metal (Pt 1 Pd, Ru, Rh) to be deposited on the substrate and passing a pulsed electric current between the substrate and the counter- electrode, the amplitude variation of the current being pre-determined.
  • the pulses of said current are cathodic with respect to the substrate and have a short activity time and / or a short working cycle with a frequency of between about 10 hertz and about 5000 hertz.
  • the electric current is a modulated inversion electrical current having pulses which are cathodic with respect to the substrate and pulses which are anodic with respect to the substrate, the cathode pulses having a short activity time and / or a short cycle time.
  • the electrode on which the deposit is made remains in contact with the bath containing the metal throughout the duration of the deposit.
  • the amount of salts entering the membrane during impregnation is high and the salts are diffused over large distances in the membrane.
  • the deposit is deep beneath the surface of the membrane.
  • gas bubbles are formed in the solid electrolyte and then cause high mechanical stresses that can tear the membrane surface and wear prematurely deposit.
  • US 5,084,144 discloses a method of manufacturing a high efficiency gas diffusion electrode containing a catalytic metal. This electrode is especially used in electrochemical cells with solid polymer electrode.
  • a gas diffusion electrode is made of a gas permeable face and, opposite to it, a catalytic face containing an electrically conductive or semiconductive support material. The method comprises: a step of impregnating the catalytic face of a solution containing a fluorinated cation exchange polymer dissolved in a polar solvent,
  • the method described in this document makes it possible to obtain a deposition of the catalytic metal on a carbon surface and not on a polymeric membrane of the NAFION® type, for example. Moreover, the roughness of the deposit obtained by this method is too low to obtain a good energy efficiency.
  • the electrochemical interface must be rough and almost two-dimensional ( ⁇ 0.01 microns) it is that is to say that the deposit must not be too deep below the surface of the membrane, gas bubbles being able to form in the solid electrolyte thus leading to high mechanical stresses that can tear the membrane on the surface and prematurely wear the deposit .
  • the object of the invention is to eliminate these disadvantages by making it possible to obtain a good adhesion of the deposit with the membrane, a deposition depth in the weak membrane and an increased roughness of said deposit, this deposition being carried out on both sides of the membrane. which implies reasoning on transient concentration profiles.
  • each of the cycles of the sequence comprises the following operations: the application, from a time to, to the electrodes of the cell of a current ( and / or a voltage) of predetermined initial amplitude having a first polarity so as to achieve an electrochemical reduction of the ions located at the interface of the polymer and one of said electrodes, this reduction generating an increase in the voltage ( and / or a decrease of the current) at the terminals of the cell, where the measurement of the voltage (and / or the current) at the terminals of the cell, o the measurement of the time flowing from the moment to, o comparing the voltage (and / or the current) measured with a predetermined first voltage (and / or a first current), where the comparison of the measured time with a predetermined inversion period, o the inversion of the current (and / or the voltage) from a moment t 'with the application of a current (and / or a voltage) of the same
  • a direct current is applied to allow the remaining ions, if any, to diffuse to a polymer-electrode interface to be reduced.
  • the ion exchange polymer may be an ion exchange membrane.
  • Said ion exchange membrane may be a NAFION ® membrane developed by the company Dupont de Nemours.
  • Said ion exchange membrane may be a FLEMION® membrane developed by ASAHI.
  • Said metal may be one of the following metals or any combination of these metals: platinum, iridium, gold, rhodium, ruthenium, palladium, silver, vanadium, chromium, iron, nickel, cobalt, copper, zinc, tin, antimony, lead , bismuth.
  • the duration of impregnation of the polymer by a solution of metal ions being dependent on the nature of the ion, it can be optimized by measuring its diffusion coefficient in the membrane and by modeling the exchange between the labile ions of the polymer and the metal ions.
  • the determination of the inversion period of the wave is based on various criteria such as the thickness of the membrane - in the case of a membrane Nafion® the number of moles of sulfonates per gram of membrane - the nature of the membrane. metal salt, the diffusion time of the metal salt in particular depending on the nature of the salt, the temperature and the pressure.
  • the value of the threshold voltage (or current) may depend on the amplitude value in current (or voltage) chosen for the succession of waves.
  • the relationship between this threshold voltage (or current) and the current (or voltage) amplitude comes from the reference current-voltage characteristic curve of the metal used: at a current intensity I corresponds a voltage E, so if one imposes I and - I (or E and -E), one poses as maximum voltage or threshold voltage E and -E (or as minimum current or current of threshold I and - I).
  • the current amplitude (or voltage) may be constant or variable.
  • the current amplitude may depend on several such as the nature of the metal, temperature, pressure.
  • the shape of the current signal may also be square, Gaussian for example ...
  • the application of the current (or voltage) to the terminals of the cell and the reversals of current (or voltage) can be achieved by a current generator, constant or not, alternating (or a voltage generator, constant or not alternative).
  • the deposit takes place as follows:
  • the measured current is below the fixed value, the voltage across the cell increases rapidly and the threshold voltage is quickly reached.
  • the current inversions are fast, which makes it possible to reduce the ions in the metallic phase at the moment when they are located at the polymer-electrode interface.
  • the voltage required to respect the fixed current value decreases, the inversion times increase to allow the ions to be renewed at the electrode-polymer interface, but they must be at least equal to the inversion period determined to prevent too deep diffusion of the ions towards the inside of the membrane, this diffusion being accelerated by the electric field.
  • the concentration of ions decreases, the diffusion of the ions inside the polymer remains substantially constant (at a low rate).
  • the process according to the invention makes it possible to increase the number of nuclei before starting their growth.
  • the deposit thus obtained is very localized, very rough. It comprises cauliflower-shaped percolating metal nano-grains characteristic of a growth according to a fractal model and is almost two-dimensional with a thickness of between 0.01 and 10 microns and preferably between 0.01 and 0, 1 micron or less than 0.01 microns.
  • these wave inversions correspond to a succession of negative alternations or cathodic current during which the metal ions and positive alternations or anodic current during which the oxidation of the surface of the metal deposit formed at the previous negative half cycle.
  • the thickness of the oxide layer is lower at the base of the nuclei.
  • the nucleation energy of new nuclei must be lower at the base rather than at the top which favors lateral rather than axial growth and, consequently, a thin and very rough deposit.
  • the metal deposition can be carried out symmetrically on the different faces of a polymer so the cells can operate in both directions by polarity inversion which is an important asset in case of poisoning and loss of performance at course of time.
  • the deposit since the deposit is electrochemical, its location is identical to that in which the electrolysis of the water is carried out, which makes it possible to minimize the quantity of metal used.
  • the polymer may be re-impregnated in a solution of the same or different metal ions.
  • the solution may contain different metal ions in order to perform a simultaneous codéposition of several metals.
  • This codeposition may for example be a platinum and ruthenium codeposition, the complex thus formed being more stable whereas a ruthenium deposit itself followed or preceded by a platinum deposition is degraded very rapidly.
  • the voltage (and / or the threshold current) will be determined according to the current-voltage curve of the metal alloy.
  • the impregnation stage of the polymer is very important because it must be fast and very quickly followed by the rinsing of the polymer and the electrolysis deposit, otherwise the ions have time to start diffusing towards the inside of the membrane.
  • the method according to the invention can be implemented in its entirety in a device comprising a cell separated into two compartments by a polymer membrane, these two compartments each comprising an inlet and a liquid outlet so as to impregnate the membrane, rinsing it and directly starting the electrodeposition. This avoids any expensive handling time and therefore detrimental to optimal deposition.
  • This device can very easily make it possible to implement an asymmetrical deposit by introducing into each compartment solutions of different metal salts, for example platinum and iridium, for the electrolysis of water to supply hydrogen fuel cells .
  • the method according to the invention operates by taking into account the properties of the two ions by imposing two threshold voltages (and / or two currents) as a function of the alternation and the metal deposit concerned.
  • This device also allows a different impregnation time for each side of the membrane for example, to obtain a similar deposit (thickness ..) on each face in the case of two different ion solutions, the two times ending at the same time. time.
  • this device allows an in situ regeneration of the cells.
  • FIG. 1 is a representation of a device implementing the method according to the invention
  • FIG. 2 is a representation of a concentration profile inside an ion exchange membrane after impregnation
  • Figure 3 is a representation of a succession of current waves applied across the cell as a function of time
  • Fig. 4 is a representation of the voltage response of the cell as a function of time
  • FIG. 5 is a representation of the voltage as a function of the current density according to the type of deposit produced.
  • FIG. 1 illustrates a device making it possible to implement the process for electroplating a metal on an ion exchange polymer according to the invention:
  • a NAFION® 1100 membrane that is to say with an equivalent weight of 1100 corresponding to 1100 moles of sulphonates per gram of membrane, is first introduced for half an hour in a boiling mixture of water and sulfuric acid H 2 SO 4 suprapur 1M then one hour in boiling water with resistivity 18 M ⁇ .cm in order to clean it on the surface and to saturate it with water.
  • the membrane is then positioned in a cell CU that separates it into two compartments C1, C2, these compartments each having an inlet and a liquid outlet.
  • a solution of concentration of 10 ⁇ 2 M platinum tetramine salts [Pt (NH 3 ) ⁇ CI 2 is then circulated in each compartment for fifteen minutes so as to obtain a concentration profile P1 (FIG. 2) and then this solution. is replaced by pure water.
  • the membrane is located between two porous titanium plates A1, A2 (or spiral platinum wires) fed in series and located on both sides of the membrane with respect to a reference potential (mass) corresponding to the potential of reference of a current generator G.
  • the current generator G, a voltage meter MV located between the generator G and the cell CU and the plate A2 are referenced with respect to the reference potential (mass).
  • the current generator G is programmable in intensity, in the direction of flow and in the form of the envelope of the generated signal. Its commands are respectively Cdlnt, Cdlnv and CdEnv.
  • the computer CA receives the following information: a voltage measured with respect to the mass CtrIV,
  • the selected current value I +/- 30 mA corresponds on the current-voltage curve of the platinum to a value of +/- 2.5 volt which is fixed as the threshold voltage, which must correspond to a deposit with a density current of 20 mA / cm 2 .
  • the maximum duration between two polarity inversions is set to 1 minute.
  • the current value I is kept constant.
  • the voltage increases simultaneously.
  • the measurement of the voltage is taken by the voltage meter MV and the corresponding information CtrIV is taken into account by the computer CA which compares the measured voltage with the first predetermined voltage + 2.5 V and the measured time with the period d predetermined inversion.
  • the current inversions follow the same process as long as there is a decrease in the amplitude of the envelope of the voltage signal, this decrease being correlated with the increase in the deposition.
  • the calculator CA calculates the variation of the amplitude and when it tends towards zero, the computer CA sends to the generator G a command to impose a direct current to allow the salts, if any, to migrate to one of the membrane-electrode interfaces in order to be reduced. Finally, the computer CA causes the shutdown of the current generator G.
  • the computer In the event of a malfunction detected from the information CtrIV, Ctrll, the computer also causes the shutdown of the current generator G.
  • the succession of alternating waves applied during the deposition is represented in FIG. 3 and the response of the system in voltage across the current leads in FIG. 4, each point corresponding to a measurement of the voltage.
  • the current generator G To impose the predetermined current at a temperature of 25 ° C, the current generator G must at least impose + 1, 23 volts or - 1, 23 volts in the direction of alternating current, which corresponds to the voltage minimum of water decomposition and about 0.2 volts per overvoltage electrode plus an ohmic drop in the membrane. Therefore, during the inversion, the voltage increases very quickly before reaching a landing. But during the duration of a given alternation, a small amount of hydrogen H 2 is formed on one side and a little oxygen O 2 on the other which remain trapped in the vicinity of the current leads.
  • the initial current comes from the inverse recombination of electrolysis: the hydrogen H 2 gives protons H + and the oxygen O 2 is reduced in water: the tension finally slowly rises again. Then, as and when alternating, the platinum surface of each side increases, overvoltages decrease and the voltage increases less and less quickly to a lower and lower equilibrium value. Gradually, the threshold voltage is no longer reached before the end of the inversion period.
  • the applied current or voltage may have a variable amplitude.
  • the signal form can also be square, Gaussian for example ...

Abstract

The invention concerns electroplating of a metal on an ion-exchanging polymer to obtain cells with electrodes-solid polymer electrolyte, said method including: a phase of impregnating a polymer with a metal ion solution for a given period, a sequence for obtaining a succession of alternating waves and wherein each of the cycles includes: a) applying, from a time t<SUB>0</SUB>, to the electrodes of the cell a current (and/or a voltage) of predetermined initial amplitude having a first polarity, b) measuring the voltage (and/or the current) at the terminals of the cell, the time measurement starting at t<SUB>0</SUB>, comparing the measured voltage (and/or current) with a first predetermined voltage (and/or current), comparing the time measured with a predetermined inversion period, c) inverting the current (and/or the voltage) from instant t' with application of a current (and/or voltage), when the measured voltage (and/or current) reaches or exceeds the threshold voltage (and/or drops below the threshold current) before said period elapses if the threshold voltage (and/or current) has not yet been reached if not at the end of said period, d) a further step of measuring the voltage (and/or the current). The invention is applicable to the preparation of electrolyzers, to water electrolysis in particular for supplying gas to fuel cells or for regenerating spent cells in situ.

Description

PROCEDE DΈLECTRODEPOSITION D'UN METAL POUR L'OBTENTION DE CELLULES A ELECTRODES-ELECTROLYTE POLYMERE SOLIDEMETHOD FOR ELECTRODEPOSITION OF METAL FOR OBTAINING SOLID POLYMERIC ELECTRODE ELECTROLYTE CELLS
La présente invention concerne un procédé d'électrodéposition d'un métal pour l'obtention de cellules à électrodes-électrolyte polymère solide. Elle s'applique plus particulièrement, mais non exclusivement, à la préparation d'électrolyseurs, à l'électrolyse de l'eau notamment pour l'alimentation en gaz de piles à combustible ou encore à la régénération de cellules usagées in situ.The present invention relates to a process for electroplating a metal to obtain solid polymer electrolyte-electrolyte cells. It applies more particularly, but not exclusively, to the preparation of electrolysers, the electrolysis of water in particular for the supply of fuel cell gas or the regeneration of used cells in situ.
De façon générale, les cellules à électrodes-électrolyte polymère solide comprennent un électrolyte polymère solide ou une membrane échangeuse d'ions dont l'épaisseur est faible (200 μm environ) portant des dépôts métalliques sur ses deux faces opposées qui servent d'électrodes, l'une étant une cathode et l'autre une anode.In general, the solid polymer electrolyte-electrolyte cells comprise a solid polymer electrolyte or an ion exchange membrane whose thickness is small (approximately 200 μm) bearing metal deposits on its two opposite faces which serve as electrodes, one being a cathode and the other anode.
Les membranes sont constituées parfois de polymère perfluorosulfonique formant un réseau de cations fixes et comprenant en outre des anions mobiles ou labiles à l'intérieur de ce réseau, par exemple les membranes FLEMION® de la compagnie ASAHI. Elles sont utilisées en électrolyse chlore-soude.The membranes sometimes consist of perfluorosulfonic polymer forming a network of fixed cations and further comprising mobile or labile anions within this network, for example FLEMION® membranes of the company ASAHI. They are used in chlor-alkali electrolysis.
Le plus souvent, les membranes sont constituées en principe de polymère perfluorosulfonique formant un réseau d'anions fixes et comprenant en outre des cations mobiles ou labiles à l'intérieur de ce réseau.Most often, the membranes consist in principle of perfluorosulfonic polymer forming a fixed anion network and further comprising mobile or labile cations within this network.
Un exemple de membranes les plus couramment utilisées sont les membranes NAFION ® développées par la société Dupont de Nemours dans laquelle les anions sont des ions SO3 " et les cations peuvent être de natures diverses : Na+, K+, Li+. Toutefois, on tend à préférer l'emploi de protons H+ car la conductivité ionique de la membrane et donc son rendement sont meilleurs.An example of membranes most commonly used are NAFION ® membranes developed by the company Dupont de Nemours in wherein the anions are SO 3 "ions and the cations can be of various natures. Na +, K +, Li +, however, tends to favor the use of protons H + for the ionic conductivity of the membrane and thus its yield are better.
L'électrolyse de l'eau peut être réalisée à l'aide de telles cellules en alimentant l'anode en eau pure : un dégagement d'oxygène a lieu à cet endroit alors que les protons produits par l'électrolyse traversent la membrane en direction de la cathode. Il y a donc circulation permanente de protons à l'intérieur de la membrane. L'hydrogène se dégage au voisinage de la cathode.The electrolysis of water can be carried out using such cells by feeding the anode in pure water: an oxygen evolution takes place there while the protons produced by the electrolysis cross the membrane in the direction of the cathode. There is therefore permanent circulation of protons inside the membrane. Hydrogen is released near the cathode.
Afin d'augmenter le rendement énergétique de ces cellules, des catalyseurs métalliques sont utilisés sous la forme de dépôts sur les faces de la membrane.In order to increase the energy efficiency of these cells, metal catalysts are used in the form of deposits on the faces of the membrane.
Le choix des métaux déposés sur la membrane dépend de plusieurs facteurs pour une réaction donnée :The choice of metals deposited on the membrane depends on several factors for a given reaction:
- le pouvoir électro-catalytique qui varie en fonction du métal et de la surface d'échange disponible,the electrocatalytic power which varies according to the metal and the available exchange surface,
- la stabilité chimique du dépôt vis-à-vis de la réaction,the chemical stability of the deposit with respect to the reaction,
- la stabilité électrochimique du dépôt en fonction du potentiel d'électrode,the electrochemical stability of the deposit as a function of the electrode potential,
- la conductivité électronique qui varie selon la porosité du dépôt, - le coût.the electronic conductivity which varies according to the porosity of the deposit, the cost.
Or, de telles cellules s'avèrent très onéreuses notamment en raison de l'utilisation de métaux précieux, d'un coût de fabrication des électrodes élevé et des performances électrochimiques des électrodes.However, such cells are very expensive especially because of the use of precious metals, a high cost of manufacturing electrodes and electrochemical performance of the electrodes.
En effet, lors de l'utilisation des cellules pour l'électrolyse de l'eau, les cations mobiles étant des protons, les membranes polymères sont alors très acides et nécessitent l'emploi de métaux nobles très coûteux tels que le platine, l'iridium, le ruthénium, l'or, le rhodium ou le palladium. II est donc important d'essayer d'optimiser le ratio quantité de métal utilisée/rendement énergétique notamment en réalisant des dépôts de métal d'une part, de faible épaisseur pour ne pas faire obstacle au cheminement des produits intervenant lors de Pélectrolyse et, d'autre part, poreux et rugueux c'est-à-dire présentant une surface d'échange maximale pour une localisation minimum afin d'augmenter la réactivité de l'électrode, soit un fort rapport d'aire spécifique active.Indeed, when using cells for the electrolysis of water, the mobile cations being protons, the polymer membranes are then very acidic and require the use of expensive noble metals such as platinum, iridium, ruthenium, gold, rhodium or palladium. It is therefore important to try to optimize the ratio of the amount of metal used / energy efficiency, in particular by making metal deposits on the one hand, of small thickness so as not to hinder the path of the products involved in electrolysis and, on the other hand, porous and rough, that is to say having a maximum exchange surface for a minimum location in order to increase the reactivity of the electrode, ie a high active surface area ratio.
Les propriétés (épaisseur, porosité, rugosité) d'un tel dépôt de métal ont pour origine un phénomène relatif à la croissance des dépôts métalliques, par exemple de métal noble, sur une surface de nature différente. En effet, il s'avère que ce phénomène tient au fait que l'énergie nécessaire à la formation d'un nucleus est supérieure à l'énergie nécessaire pour la croissance d'un nucleus existant. Ainsi, plutôt que de former une monocouche régulière sur toute la surface puis d'empiler les monocouches, on observe, dans un premier temps, une croissance en ilôts isolés appelés nuclei. Ensuite, un dépôt continue à se développer à partir des nuclei selon une croissance dendritique. Or, pour avoir un dépôt présentant des propriétés de porosité et de rugosité satisfaisantes, il faut favoriser un développement selon un modèle fractal c'est-à-dire dans une direction parallèle à la surface et non dendritique c'est- à-dire dans une direction normale par rapport à la surface.The properties (thickness, porosity, roughness) of such a metal deposit originate from a phenomenon relating to the growth of metal deposits, for example of noble metal, on a surface of a different nature. Indeed, it turns out that this phenomenon is due to the fact that the energy necessary for the formation of a nucleus is higher than the energy necessary for the growth of an existing nucleus. Thus, rather than forming a regular monolayer on the whole surface and then stacking the monolayers, we first observe a growth in isolated islands called nuclei. Then, a deposition continues to grow from nuclei in dendritic growth. However, to have a deposit with properties of porosity and satisfactory roughness, it is necessary to promote a development according to a fractal model that is to say in a direction parallel to the surface and not dendritic that is to say in a normal direction relative to the surface.
Enfin, ces dépôts doivent présenter une adhérence suffisante avec la membrane pour éviter des décollements produits par la formation de gaz à la jonction de la membrane et du dépôt.Finally, these deposits must have sufficient adhesion with the membrane to avoid detachments produced by the formation of gas at the junction of the membrane and the deposit.
Différentes solutions ont déjà été envisagées :Different solutions have already been considered:
Le document WO 00/28114 (US 6 080 504) décrit une électrode à diffusion gazeuse pour pile à combustible à membrane échangeuse de protons fabriquée par électrodéposition d'un métal catalytique sous forme nanocristalline sur un substrat. Ce résultat est obtenu en mettant en contact un substrat électriquement conducteur et une contre-électrode avec un bain galvanoplastique contenant des ions d'un métal (Pt1 Pd, Ru, Rh) devant être déposé sur le substrat et en faisant passer un courant électrique puisé entre le substrat et la contre-électrode, la variation d'amplitude du courant étant pré-déterminée. Les impulsions dudit courant sont cathodiques par rapport au substrat et ont un temps d'activité court et/ou un cycle de travail court avec une fréquence comprise entre 10 hertz environ et 5000 hertz environ. Dans une réalisation préférée, le courant électrique est un courant électrique d'inversion modulé présentant des impulsions qui sont cathodiques par rapport au substrat et des impulsions qui sont anodiques par rapport au substrat, les impulsions cathodiques ayant un temps d'activité court et/ou un temps de cycle court.WO 00/28114 (US 6,080,504) discloses a proton exchange membrane fuel cell gas diffusion electrode made by electroplating a nanocrystalline catalytic metal onto a substrate. This result is obtained by putting in contact an electrically conductive substrate and a counter electrode with an electroplating bath containing ions of a metal (Pt 1 Pd, Ru, Rh) to be deposited on the substrate and passing a pulsed electric current between the substrate and the counter- electrode, the amplitude variation of the current being pre-determined. The pulses of said current are cathodic with respect to the substrate and have a short activity time and / or a short working cycle with a frequency of between about 10 hertz and about 5000 hertz. In a preferred embodiment, the electric current is a modulated inversion electrical current having pulses which are cathodic with respect to the substrate and pulses which are anodic with respect to the substrate, the cathode pulses having a short activity time and / or a short cycle time.
Le procédé décrit dans ce document permet d'obtenir un dépôt sur une seule face. Or, dans le cas de cellules électrochimiques à électrode- électrolyte polymère solide, il faut obtenir un dépôt symétrique sur les deux faces de la membrane.The method described in this document provides a deposit on one side. However, in the case of electrochemical cells with solid polymer electrolyte electrode, it is necessary to obtain a symmetrical deposit on both sides of the membrane.
De plus, l'électrode sur laquelle se fait le dépôt reste en contact avec le bain contenant le métal durant toute la durée du dépôt. La quantité de sels pénétrant dans la membrane durant l'imprégnation est élevée et la diffusion des sels se fait sur des distances importantes dans la membrane. Par conséquent, le dépôt est profond sous la surface de la membrane. Or, lors de la réaction électrochimique, des bulles de gaz se forment dans l'électrolyte solide et entraînent alors de fortes contraintes mécaniques qui peuvent déchirer la membrane en surface et user prématurément le dépôt.In addition, the electrode on which the deposit is made remains in contact with the bath containing the metal throughout the duration of the deposit. The amount of salts entering the membrane during impregnation is high and the salts are diffused over large distances in the membrane. As a result, the deposit is deep beneath the surface of the membrane. However, during the electrochemical reaction, gas bubbles are formed in the solid electrolyte and then cause high mechanical stresses that can tear the membrane surface and wear prematurely deposit.
Le document US 5 084 144 décrit un procédé de fabrication d'une électrode haute efficacité à diffusion de gaz contenant un métal catalytique. Cette électrode est notamment utilisée dans les cellules électrochimiques à électrode polymère solide. Une électrode à diffusion de gaz est constituée d'une face perméable aux gaz et, opposée à celle-ci, d'une face catalysable contenant un matériau de support électriquement conducteur ou semiconducteur. Le procédé comprend : - une étape d'imprégnation de la face catalysable d'une solution contenant un polymère échangeur de cation fluoré dissout dans un solvant polaire,US 5,084,144 discloses a method of manufacturing a high efficiency gas diffusion electrode containing a catalytic metal. This electrode is especially used in electrochemical cells with solid polymer electrode. A gas diffusion electrode is made of a gas permeable face and, opposite to it, a catalytic face containing an electrically conductive or semiconductive support material. The method comprises: a step of impregnating the catalytic face of a solution containing a fluorinated cation exchange polymer dissolved in a polar solvent,
- une étape dite de placage durant laquelle l'électrode ainsi traitée est placée dans une solution contenant des cations d'un métal sous une forme oxydée,a so-called plating step during which the electrode thus treated is placed in a solution containing cations of a metal in an oxidized form,
- l'application d'un courant continu et l'interruption de ce courant de manière à obtenir un dépôt ayant une granulométrie> 10 nm et pour lequel la charge en métal obtenu est comprise entre 0,01 et 2 mg par cm2 de la surface catalysable.the application of a direct current and the interruption of this current so as to obtain a deposit having a particle size> 10 nm and for which the metal charge obtained is between 0.01 and 2 mg per cm 2 of the catalytic surface.
Le procédé décrit dans ce document permet d'obtenir un dépôt du métal catalytique sur une surface de carbone et non sur une membrane polymérique du type NAFION® par exemple. Par ailleurs, la rugosité du dépôt obtenu par ce procédé est trop faible pour obtenir un bon rendement énergétique.The method described in this document makes it possible to obtain a deposition of the catalytic metal on a carbon surface and not on a polymeric membrane of the NAFION® type, for example. Moreover, the roughness of the deposit obtained by this method is too low to obtain a good energy efficiency.
De plus, pour la préparation d'électrolyseurs de l'eau, compte tenu de la formation d'hydrogène et d'oxygène gazeux, l'interface électrochimique doit être rugueuse et quasi bi-dimensionnelle (< 0, 01 microns) c'est-à-dire que le dépôt ne doit pas être trop profond sous la surface de la membrane, des bulles de gaz pouvant se former dans l'électrolyte solide entraînant ainsi de fortes contraintes mécaniques qui peuvent déchirer la membrane en surface et user prématurément le dépôt.In addition, for the preparation of electrolysers of water, given the formation of hydrogen and oxygen gas, the electrochemical interface must be rough and almost two-dimensional (<0.01 microns) it is that is to say that the deposit must not be too deep below the surface of the membrane, gas bubbles being able to form in the solid electrolyte thus leading to high mechanical stresses that can tear the membrane on the surface and prematurely wear the deposit .
Aucune des solutions rencontrées ne tient compte de la diminution de la concentration en ions dans la membrane au fur et à mesure de la réduction desdits ions et par conséquent, de la baisse de la vitesse d'apport de matière à l'interface avec le temps. Or, il n'y a donc pas de raison d'appliquer des fréquences pré-programmées et encore moins identiques : en effet une fréquence pas assez élevée favorisera une croissance dendritique et beaucoup de cations vont diffuser vers le centre de la membrane et être ainsi perdus pour le dépôt et difficiles à recycler. Une fréquence trop élevée deviendra rapidement inutile les ions n'ayant pas le temps d'arriver à l'interface électrode-membrane. L'invention a pour objet de supprimer ces inconvénients en permettant d'obtenir une bonne adhérence du dépôt avec la membrane, une profondeur de dépôt dans la membrane faible et une rugosité accrue dudit dépôt, ce dépôt étant réalisé sur les deux faces de la membrane ce qui implique de raisonner sur des profils de concentration transitoires.None of the solutions encountered takes into account the decrease in the ion concentration in the membrane as the reduction of said ions and consequently, the decrease in the rate of input of material to the interface with time. . However, there is no reason to apply pre-programmed frequencies and even less identical: in fact a not high enough frequency will promote dendritic growth and many cations will diffuse towards the center of the membrane and thus be lost for deposit and difficult to recycle. Too high a frequency will quickly become unnecessary ions that do not have time to reach the electrode-membrane interface. The object of the invention is to eliminate these disadvantages by making it possible to obtain a good adhesion of the deposit with the membrane, a deposition depth in the weak membrane and an increased roughness of said deposit, this deposition being carried out on both sides of the membrane. which implies reasoning on transient concentration profiles.
A cet effet, elle propose un procédé d'électrodéposition d'un métal sur un polymère échangeur d'ions pour l'obtention de cellules à électrodes- électrolyte polymère solide, ce procédé comprenant :For this purpose, it proposes a process for electroplating a metal on an ion exchange polymer to obtain solid polymer electrolyte-electrolyte cells, said method comprising:
- une phase d'imprégnation du polymère par une solution d'ions métalliques pendant une période donnée de façon à ne faire entrer qu'un nombre d'ions nécessaires et suffisants pour effectuer le dépôt, ladite période étant déterminée en fonction de la profondeur de diffusion des ions tolérée étant entendu que, plus la durée d'imprégnation est longue, plus les ions auront le temps de diffuser vers l'intérieur de la membrane,a phase of impregnation of the polymer with a solution of metal ions during a given period so as to enter only a number of ions necessary and sufficient to effect the deposit, said period being determined as a function of the depth of it is understood that the longer the impregnation time, the more time the ions will have to diffuse into the interior of the membrane,
- une séquence permettant d'obtenir une succession d'ondes alternatives et dans laquelle chacun des cycles de la séquence comprend les opérations suivantes : o l'application, à partir d'un temps to, aux électrodes de la cellule d'un courant (et/ou d'une tension) d'amplitude initiale prédéterminée présentant une première polarité de manière à réaliser une réduction électrochimique des ions localisés à l'interface du polymère et de l'une desdites électrodes, cette réduction engendrant un accroissement de la tension (et/ou une diminution du courant) aux bornes de la cellule, o la mesure de la tension (et/ou du courant) aux bornes de la cellule, o la mesure du temps s'écoulant à partir de l'instant to, o la comparaison de la tension (et/ou du courant) mesurée avec une première tension (et/ou un premier courant) prédéterminée, o la comparaison du temps mesuré avec une période d'inversion prédéterminée, o l'inversion du courant (et/ou de la tension) à partir d'un instant t' avec l'application d'un courant (et/ou d'une tension) de même amplitude que l'amplitude initiale mais de polarité inversée, lorsque la tension (et/ou le courant) mesurée atteint ou dépasse la tension (et/ou s'abaisse au-dessous du courant) de seuil avant l'expiration de ladite période si la tension (et/ou le courant) de seuil n'a pas encore été atteinte sinon au moment de l'expiration de ladite période, o une nouvelle étape de mesure de la tension (ou du courant) aux bornes de la cellule, o une nouvelle mesure du temps s'écoulant à partir de l'instant t' d'inversion, o la comparaison de la tension (et/ou du courant) nouvellement mesurée avec une deuxième tension (et/ou un deuxième courant) de seuil pouvant présenter une même amplitude que la première tension (et/ou le premier courant) de seuil mais de polarité inversée, o l'inversion du courant (et/ou de la tension) avec l'application d'un courant (et/ou d'une tension) de même amplitude que l'amplitude initiale mais de polarité inversée par rapport au courant du cycle précédent, lorsque la tension (et/ou le courant) mesurée atteint ou dépasse la tension (et/ou s'abaisse au- dessous du courant) de seuil avant l'expiration de ladite période ou si la tension (et/ou le courant) de seuil n'a pas encore été atteinte sinon au moment de l'expiration de ladite période, o puis de nouveau les mesures de tension (et/ou de courant) et de temps, les comparaisons et les inversions de courant (et/ou de tension).a sequence making it possible to obtain a succession of alternative waves and in which each of the cycles of the sequence comprises the following operations: the application, from a time to, to the electrodes of the cell of a current ( and / or a voltage) of predetermined initial amplitude having a first polarity so as to achieve an electrochemical reduction of the ions located at the interface of the polymer and one of said electrodes, this reduction generating an increase in the voltage ( and / or a decrease of the current) at the terminals of the cell, where the measurement of the voltage (and / or the current) at the terminals of the cell, o the measurement of the time flowing from the moment to, o comparing the voltage (and / or the current) measured with a predetermined first voltage (and / or a first current), where the comparison of the measured time with a predetermined inversion period, o the inversion of the current (and / or the voltage) from a moment t 'with the application of a current (and / or a voltage) of the same amplitude as the initial amplitude but of polarity inverted, when the measured voltage (and / or current) reaches or exceeds the threshold voltage (and / or drops below the current) before the expiration of said period if the voltage (and / or current) threshold has not yet been reached, except at the expiry of the said period, o a new step of measuring the voltage (or current) at the terminals of the cell, o a new measurement of the time flowing to from the moment of inversion, where the comparison of the newly measured voltage (and / or current) with a second voltage (and / or a second current) of threshold may have the same amplitude as the first voltage ( and / or the first current) of threshold but of inverted polarity, where the inversion of the current (and / or the voltage) with the application of a court ant (and / or a voltage) of the same amplitude as the initial amplitude but of reversed polarity with respect to the current of the preceding cycle, when the measured voltage (and / or current) reaches or exceeds the voltage (and / or falls below the threshold current) before the expiration of said period or if the threshold voltage (and / or current) has not yet been reached, except at the expiry of said period, o then again the measurements of voltage (and / or current) and time, comparisons and inversions of current (and / or voltage).
En outre, après l'obtention d'un dépôt présentant les caractéristiques souhaitées, on applique un courant continu afin de permettre aux ions restants, s'il y en a, de diffuser vers une interface polymère-électrode pour être réduit. Ledit polymère échangeur d'ions pourra être une membrane échangeuse d'ions.In addition, after obtaining a deposit having the desired characteristics, a direct current is applied to allow the remaining ions, if any, to diffuse to a polymer-electrode interface to be reduced. The ion exchange polymer may be an ion exchange membrane.
Ladite membrane échangeuse d'ions pourra être une membrane NAFION ® développée par la société Dupont de Nemours.Said ion exchange membrane may be a NAFION ® membrane developed by the company Dupont de Nemours.
Ladite membrane échangeuse d'ions pourra être une membrane FLEMION® développée par la société ASAHI.Said ion exchange membrane may be a FLEMION® membrane developed by ASAHI.
Ledit métal pourra être un des métaux suivants ou toute combinaison de mélange de ces métaux : platine, iridium, or, rhodium, ruthénium, palladium, argent, vanadium, chrome, fer, nickel, cobalt, cuivre, zinc, étain, antimoine, plomb, bismuth.Said metal may be one of the following metals or any combination of these metals: platinum, iridium, gold, rhodium, ruthenium, palladium, silver, vanadium, chromium, iron, nickel, cobalt, copper, zinc, tin, antimony, lead , bismuth.
La durée d'imprégnation du polymère par une solution d'ions métalliques étant dépendante de la nature de l'ion, elle pourra être optimisée en mesurant son coefficient de diffusion dans la membrane et en modélisant l'échange entre les ions labiles du polymère et les ions métalliques.The duration of impregnation of the polymer by a solution of metal ions being dependent on the nature of the ion, it can be optimized by measuring its diffusion coefficient in the membrane and by modeling the exchange between the labile ions of the polymer and the metal ions.
La détermination de la période d'inversion de l'onde est basée sur différents critères tels que l'épaisseur de la membrane - dans le cas d'une membrane Nafion® le nombre de moles de sulfonates par gramme de membrane -, la nature du sel métallique, le temps de diffusion du sel métallique notamment en fonction de la nature du sel, de la température et de la pression.The determination of the inversion period of the wave is based on various criteria such as the thickness of the membrane - in the case of a membrane Nafion® the number of moles of sulfonates per gram of membrane - the nature of the membrane. metal salt, the diffusion time of the metal salt in particular depending on the nature of the salt, the temperature and the pressure.
La valeur de la tension (ou du courant) de seuil pourra dépendre de la valeur d'amplitude en courant (ou en tension) choisie pour la succession d'ondes. La relation entre cette tension (ou ce courant) de seuil et l'amplitude de courant (ou de tension) vient de la courbe courant-tension de référence caractéristique du métal utilisé : à une intensité de courant I correspond une tension E, ainsi si l'on impose I et - I (ou E et -E), on pose comme tension maximum ou tension de seuil E et -E (ou comme courant minimum ou courant de seuil I et - I). L'amplitude en courant (ou en tension) pourra être constante ou variable.The value of the threshold voltage (or current) may depend on the amplitude value in current (or voltage) chosen for the succession of waves. The relationship between this threshold voltage (or current) and the current (or voltage) amplitude comes from the reference current-voltage characteristic curve of the metal used: at a current intensity I corresponds a voltage E, so if one imposes I and - I (or E and -E), one poses as maximum voltage or threshold voltage E and -E (or as minimum current or current of threshold I and - I). The current amplitude (or voltage) may be constant or variable.
L'amplitude en courant (ou en tension) pourra dépendre de plusieurs tels que la nature du métal, la température, la pression.The current amplitude (or voltage) may depend on several such as the nature of the metal, temperature, pressure.
La forme du signal en courant (ou en tension) pourra également être par exemple carrée, gaussienne...The shape of the current signal (or voltage) may also be square, Gaussian for example ...
L'application du courant (ou de la tension) aux bornes de la cellule et les inversions de courant (ou de tension) pourront être réalisés par un générateur de courant, constant ou non, alternatif (ou un générateur de tension, constante ou non, alternative).The application of the current (or voltage) to the terminals of the cell and the reversals of current (or voltage) can be achieved by a current generator, constant or not, alternating (or a voltage generator, constant or not alternative).
Le dépôt se déroule de la façon suivante :The deposit takes place as follows:
Au début, beaucoup d'ions sont présents à l'interface électrode-membrane, le courant mesuré est en dessous de la valeur fixée, la tension aux bornes de la cellule augmente rapidement et la tension de seuil est alors rapidement atteinte. Ainsi, les inversions de courant sont rapides ce qui permet de réduire les ions en phase métallique au moment où ils sont localisés à l'interface polymère-électrode.At the beginning, many ions are present at the electrode-membrane interface, the measured current is below the fixed value, the voltage across the cell increases rapidly and the threshold voltage is quickly reached. Thus, the current inversions are fast, which makes it possible to reduce the ions in the metallic phase at the moment when they are located at the polymer-electrode interface.
Au fur et à mesure de la formation du dépôt, la tension nécessaire pour respecter la valeur de courant fixée diminue, les durées d'inversion augmentent pour permettre de renouveler les ions à l'interface électrode- polymère mais elles doivent être au minimum égales à la période d'inversion déterminée pour empêcher une diffusion trop profonde des ions vers l'intérieur de la membrane, cette diffusion étant accélérée par le champ électrique.Du fait que la concentration en ions diminue, la diffusion des ions à l'intérieur du polymère demeure sensiblement constante (à un faible taux).As the deposit is formed, the voltage required to respect the fixed current value decreases, the inversion times increase to allow the ions to be renewed at the electrode-polymer interface, but they must be at least equal to the inversion period determined to prevent too deep diffusion of the ions towards the inside of the membrane, this diffusion being accelerated by the electric field. As the concentration of ions decreases, the diffusion of the ions inside the polymer remains substantially constant (at a low rate).
Une fois la durée de dépôt atteinte, les inversions sont arrêtées au profit d'une onde continue afin de permettre aux ions restants s'il y en a de diffuser vers une interface polymère-électrode pour être réduit. Selon un premier avantage, le procédé selon l'invention permet d'augmenter le nombre de nuclei avant d'entamer leur croissance. Le dépôt ainsi obtenu est très localisé, très rugueux. Il comporte des nano-grains de métal percolants, en forme de choux fleur caractéristique d'une croissance selon un modèle fractal et il est quasi bidimensionnel avec une épaisseur comprise entre 0,01 et 10 microns et de préférence entre 0,01 et 0,1 micron, voire inférieure à 0,01 microns.Once the deposition time is reached, the inversions are stopped in favor of a continuous wave to allow the remaining ions, if any, to diffuse to a polymer-electrode interface to be reduced. According to a first advantage, the process according to the invention makes it possible to increase the number of nuclei before starting their growth. The deposit thus obtained is very localized, very rough. It comprises cauliflower-shaped percolating metal nano-grains characteristic of a growth according to a fractal model and is almost two-dimensional with a thickness of between 0.01 and 10 microns and preferably between 0.01 and 0, 1 micron or less than 0.01 microns.
Pour une électrode considérée, ces inversions d'onde correspondent à une succession d'alternances négatives ou courant cathodique pendant lesquelles a lieu la réduction des ions en métal et d'alternances positives ou courant anodique pendant lesquelles a lieu l'oxydation de la surface du dépôt métallique formé à l'alternance négative précédente.For an electrode considered, these wave inversions correspond to a succession of negative alternations or cathodic current during which the metal ions and positive alternations or anodic current during which the oxidation of the surface of the metal deposit formed at the previous negative half cycle.
Par conséquent, en début d'alternance négative, la réduction des cations métalliques se fait sur des nuclei oxydés en surface à l'alternance positive précédente ; on constate que cela favorise la formation de nouveaux nuclei plutôt qu'une croissance du nuclei support d'où la formation d'une structure fractale.Consequently, at the beginning of negative alternation, the reduction of the metal cations is done on nuclei oxidized at the surface at the previous positive half cycle; it is found that this favors the formation of new nuclei rather than a growth of the support nuclei, hence the formation of a fractal structure.
Par ailleurs, pour des raisons thermodynamiques et cinétiques, l'épaisseur de la couche d'oxyde est plus faible à la base des nuclei. Ainsi, l'énergie de germination de nouveaux nuclei doit être plus faible à la base plutôt qu'au sommet ce qui favorise une croissance latérale plutôt qu'axiale et, par conséquent, un dépôt peu épais et très rugueux.Moreover, for thermodynamic and kinetic reasons, the thickness of the oxide layer is lower at the base of the nuclei. Thus, the nucleation energy of new nuclei must be lower at the base rather than at the top which favors lateral rather than axial growth and, consequently, a thin and very rough deposit.
Selon un troisième avantage, le dépôt métallique pourra être effectué symétriquement sur les différentes faces d'un polymère ainsi les cellules pourront fonctionner dans les deux sens par inversion de polarité ce qui est un atout important en cas d'empoisonnement et de perte de performances au cours du temps. Selon un quatrième avantage, le dépôt étant électrochimique, sa localisation est identique à celle où s'effectue Pélectrolyse de l'eau ce qui permet de minimiser la quantité de métal utilisée.According to a third advantage, the metal deposition can be carried out symmetrically on the different faces of a polymer so the cells can operate in both directions by polarity inversion which is an important asset in case of poisoning and loss of performance at course of time. According to a fourth advantage, since the deposit is electrochemical, its location is identical to that in which the electrolysis of the water is carried out, which makes it possible to minimize the quantity of metal used.
Selon un cinquième avantage, le polymère pourra être re-imprégné dans une solution d'ions métalliques identiques ou différents.According to a fifth advantage, the polymer may be re-impregnated in a solution of the same or different metal ions.
Selon un sixième avantage, la solution pourra contenir des ions métalliques différents afin d'effectuer une codéposition simultanée de plusieurs métaux. Cette codéposition pourra être par exemple une codéposition de platine et de ruthénium, le complexe ainsi formé étant plus stable alors qu'un dépôt de ruthénium même suivi ou précédé d'un dépôt de platine se dégrade très rapidement. Dans ce cas, la tension (et/ou le courant de seuil) sera déterminée selon la courbe courant-tension de l'alliage de métaux.According to a sixth advantage, the solution may contain different metal ions in order to perform a simultaneous codéposition of several metals. This codeposition may for example be a platinum and ruthenium codeposition, the complex thus formed being more stable whereas a ruthenium deposit itself followed or preceded by a platinum deposition is degraded very rapidly. In this case, the voltage (and / or the threshold current) will be determined according to the current-voltage curve of the metal alloy.
L'étape d'imprégnation du polymère est très importante car elle doit être rapide et très vite suivie du rinçage du polymère puis du dépôt par électrolyse sinon les ions ont le temps de commencer à diffuser vers l'intérieur de la membrane.The impregnation stage of the polymer is very important because it must be fast and very quickly followed by the rinsing of the polymer and the electrolysis deposit, otherwise the ions have time to start diffusing towards the inside of the membrane.
A cet effet, le procédé selon l'invention pourra être mis en œuvre dans son intégralité dans un dispositif comportant une cellule séparée en deux compartiments par une membrane polymère, ces deux compartiments comprenant chacun une entrée et une sortie de liquide de façon à imprégner la membrane, à la rincer puis à lancer directement l'électrodéposition. On évite ainsi toute manipulation coûteuse en temps et donc préjudiciable à un dépôt optimal.For this purpose, the method according to the invention can be implemented in its entirety in a device comprising a cell separated into two compartments by a polymer membrane, these two compartments each comprising an inlet and a liquid outlet so as to impregnate the membrane, rinsing it and directly starting the electrodeposition. This avoids any expensive handling time and therefore detrimental to optimal deposition.
Ce dispositif pourra très facilement permettre de mettre en œuvre un dépôt dissymétrique par introduction dans chaque compartiment de solutions de sels métalliques différents par exemple de platine et d'iridium en vue de l'électrolyse de l'eau pour alimenter en hydrogène des piles à combustible. Dans le cas d'un dépôt dissymétrique, le procédé selon l'invention fonctionne en prenant en compte les propriétés des deux ions en imposant deux tensions (et/ou deux courants) de seuil en fonction de l'alternance et du dépôt métallique concerné.This device can very easily make it possible to implement an asymmetrical deposit by introducing into each compartment solutions of different metal salts, for example platinum and iridium, for the electrolysis of water to supply hydrogen fuel cells . In the case of an asymmetrical deposit, the method according to the invention operates by taking into account the properties of the two ions by imposing two threshold voltages (and / or two currents) as a function of the alternation and the metal deposit concerned.
Ce dispositif permet également un temps d'imprégnation différent pour chaque face de la membrane par exemple, pour obtenir un dépôt similaire (épaisseur..) sur chaque face dans le cas de deux solutions d'ions différents, les deux temps se terminant en même temps.This device also allows a different impregnation time for each side of the membrane for example, to obtain a similar deposit (thickness ..) on each face in the case of two different ion solutions, the two times ending at the same time. time.
Enfin, ce dispositif permet une régénération in situ des cellules.Finally, this device allows an in situ regeneration of the cells.
Des modes d'exécution de l'invention seront décrits ci-après, à titre d'exemples non limitatifs, avec référence aux dessins annexés dans lesquels :Embodiments of the invention will be described below, by way of non-limiting examples, with reference to the accompanying drawings in which:
La figure 1 est une représentation d'un dispositif mettant en œuvre le procédé selon l'invention ;FIG. 1 is a representation of a device implementing the method according to the invention;
La figure 2 est une représentation d'un profil de concentration à l'intérieur d'une membrane échangeuse d'ions après imprégnation,FIG. 2 is a representation of a concentration profile inside an ion exchange membrane after impregnation,
La figure 3 est une représentation d'une succession d'ondes en courant appliquée aux bornes de la cellule en fonction du temps ;Figure 3 is a representation of a succession of current waves applied across the cell as a function of time;
La figure 4 est une représentation de la réponse en tension de la cellule en fonction du temps ;Fig. 4 is a representation of the voltage response of the cell as a function of time;
La figure 5 est une représentation de la tension en fonction de la densité de courant selon le type de dépôt réalisé.FIG. 5 is a representation of the voltage as a function of the current density according to the type of deposit produced.
L'exemple de la figure 1 illustre un dispositif permettant de mettre en œuvre le procédé d'électrodéposition d'un métal sur un polymère échangeur d'ions selon l'invention : Une membrane NAFION® 1100 c'est-à-dire avec un poids équivalent de 1100 correspondant à 1100 moles de sulfonates par gramme de membrane est préalablement introduite une demi-heure dans un mélange bouillant d'eau et d'acide sulfurique H2SO4 suprapur 1M puis une heure dans de l'eau bouillante de résistivité 18 MΩ.cm afin de la nettoyer en surface et à la saturer en eau.The example of FIG. 1 illustrates a device making it possible to implement the process for electroplating a metal on an ion exchange polymer according to the invention: A NAFION® 1100 membrane, that is to say with an equivalent weight of 1100 corresponding to 1100 moles of sulphonates per gram of membrane, is first introduced for half an hour in a boiling mixture of water and sulfuric acid H 2 SO 4 suprapur 1M then one hour in boiling water with resistivity 18 MΩ.cm in order to clean it on the surface and to saturate it with water.
La membrane est alors positionnée dans une cellule CU qu'elle sépare en deux compartiments C1 , C2, ces compartiments comportent chacun une arrivée et une sortie de liquide.The membrane is then positioned in a cell CU that separates it into two compartments C1, C2, these compartments each having an inlet and a liquid outlet.
On fait alors circuler dans chaque compartiment, pendant quinze minutes, une solution de concentration 10~2 M en sels de platine tétramine [Pt(NH3)^CI2 de façon à obtenir un profil de concentration P1 (Figure 2) puis cette solution est remplacée par de l'eau pure.A solution of concentration of 10 ~ 2 M platinum tetramine salts [Pt (NH 3 ) ^ CI 2 is then circulated in each compartment for fifteen minutes so as to obtain a concentration profile P1 (FIG. 2) and then this solution. is replaced by pure water.
La membrane est située entre deux plaques de titane poreux A1 , A2 (ou des fils de platine en spirale) alimentées en série et situées de part et d'autre de la membrane par rapport à un potentiel de référence (masse) correspondant au potentiel de référence d'un générateur de courant G.The membrane is located between two porous titanium plates A1, A2 (or spiral platinum wires) fed in series and located on both sides of the membrane with respect to a reference potential (mass) corresponding to the potential of reference of a current generator G.
Par conséquent, le générateur de courant G, un mesureur de tension MV situé entre le générateur G et la cellule CU et la plaque A2 sont référencés par rapport au potentiel de référence (masse).Therefore, the current generator G, a voltage meter MV located between the generator G and the cell CU and the plate A2 are referenced with respect to the reference potential (mass).
Le générateur de courant G est programmable en intensité, en sens du débit et quant à la forme de l'enveloppe du signal généré. Ses commandes sont respectivement Cdlnt, Cdlnv et CdEnv.The current generator G is programmable in intensity, in the direction of flow and in the form of the envelope of the generated signal. Its commands are respectively Cdlnt, Cdlnv and CdEnv.
Le calculateur CA reçoit les informations suivantes : - une tension mesurée par rapport à la masse CtrIV,The computer CA receives the following information: a voltage measured with respect to the mass CtrIV,
- un courant traversant Ctrll,a current crossing Ctrll,
- une enveloppe du signal de tension déterminée CtrIE (carrée, gaussienne...). La valeur de courant choisie I = +/- 30 mA correspond sur la courbe courant- tension du platine à une valeur de +/- 2,5 volt qui est fixée comme tension de seuil, ce qui doit correspondre à un dépôt avec une densité de courant de 20 mA/cm2.an envelope of the determined tension signal CtrIE (square, Gaussian, etc.). The selected current value I = +/- 30 mA corresponds on the current-voltage curve of the platinum to a value of +/- 2.5 volt which is fixed as the threshold voltage, which must correspond to a deposit with a density current of 20 mA / cm 2 .
Les mesures de tension sont réalisées toutes les deux secondes.Voltage measurements are performed every two seconds.
La durée maximale entre deux inversions de polarité est fixée à 1 minute.The maximum duration between two polarity inversions is set to 1 minute.
Le calculateur CA commande la mise en route du générateur de courant G et l'application, à partir d'un temps to, aux amenées de courant A1 , A2, d'un courant d'amplitude initiale prédéterminée I = + 30 mA de manière à réaliser une réduction électrochimique des ions localisés à l'interface de la membrane et de l'amenée de courant A1 , cette réduction engendrant un accroissement de la tension aux bornes de la cellule CU. La valeur de courant I est maintenue constante. La tension augmente simultanément. La mesure de la tension est prise par le mesureur de tension MV et l'information correspondante CtrIV est prise en compte par le calculateur CA qui compare la tension mesurée avec la première tension prédéterminée + 2,5 V et le temps mesuré avec la période d'inversion prédéterminée.The computer CA controls the start of the current generator G and the application, from a time to, to the current leads A1, A2, of a predetermined initial amplitude current I = + 30 mA. to perform an electrochemical reduction of the ions located at the interface of the membrane and the current supply A1, this reduction generating an increase in the voltage across the cell CU. The current value I is kept constant. The voltage increases simultaneously. The measurement of the voltage is taken by the voltage meter MV and the corresponding information CtrIV is taken into account by the computer CA which compares the measured voltage with the first predetermined voltage + 2.5 V and the measured time with the period d predetermined inversion.
Puis, le calculateur CA commande l'inversion du courant avec l'application d'un courant de même amplitude que l'amplitude initiale mais de polarité inversée, soit I = - 30 mA, de manière à réaliser une réduction électrochimique des ions localisés à l'interface de la membrane et de l'amenée de courant A2, lorsque la tension mesurée atteint ou dépasse la tension de seuil avant l'expiration de ladite période ou si la tension de seuil n'a pas encore été atteinte sinon au moment de l'expiration de ladite période.Then, the computer CA controls the inversion of the current with the application of a current of the same amplitude as the initial amplitude but of reversed polarity, ie I = -30 mA, so as to achieve an electrochemical reduction of the ions located at the interface of the membrane and of the current supply A2, when the measured voltage reaches or exceeds the threshold voltage before the expiry of said period or if the threshold voltage has not yet been reached, except at the moment of the expiry of that period.
Les inversions de courant s'enchaînent selon le même processus tant qu'il y a une diminution de l'amplitude de l'enveloppe du signal de tension, cette diminution étant corrélée à l'augmentation du dépôt. Le calculateur CA calcule la variation de l'amplitude et lorsqu'elle tend vers zéro, le calculateur CA envoie au générateur G une commande pour imposer un courant continu pour permettre aux sels, s'il y en a, de migrer vers une des interfaces membrane-électrode afin d'être réduits. Enfin, le calculateur CA provoque l'arrêt du générateur de courant G.The current inversions follow the same process as long as there is a decrease in the amplitude of the envelope of the voltage signal, this decrease being correlated with the increase in the deposition. The calculator CA calculates the variation of the amplitude and when it tends towards zero, the computer CA sends to the generator G a command to impose a direct current to allow the salts, if any, to migrate to one of the membrane-electrode interfaces in order to be reduced. Finally, the computer CA causes the shutdown of the current generator G.
II est à noter que l'information correspondant au courant appliqué par le générateur G aux bornes de la cellule (Ctrll) est prise en compte par le calculateur CA (vérification de bon fonctionnement de l'électrolyse).It should be noted that the information corresponding to the current applied by the generator G to the terminals of the cell (Ctr11) is taken into account by the computer CA (verification of the proper functioning of the electrolysis).
En cas de dysfonctionnement détecté à partir des informations CtrIV, Ctrll, le calculateur provoque également l'arrêt du générateur de courant G.In the event of a malfunction detected from the information CtrIV, Ctrll, the computer also causes the shutdown of the current generator G.
La succession d'ondes alternatives appliquée pendant le dépôt est représentée sur la figure 3 et la réponse du système en tension aux bornes des amenées de courant sur la figure 4, chaque point correspondant à une mesure de la tension.The succession of alternating waves applied during the deposition is represented in FIG. 3 and the response of the system in voltage across the current leads in FIG. 4, each point corresponding to a measurement of the voltage.
Le dépôt métallique évolue en fonction des inversions et les réactions électrochimiques aux interfaces membrane/amenées de courant :The metallic deposition evolves as a function of inversions and electrochemical reactions at membrane interfaces / current leads:
Lorsqu'une amenée de courant est soumise à une alternance positive (courant anodique), il se produit la décomposition de l'eau selon : H2O → 1/2 O2 + 2 H+ + 2 eWhen power supply is subjected to a positive alternation (anode current), the water decomposition occurs according to: H 2 O → 1/2 O 2 + 2 H + + 2 e
Pendant ce temps, sur l'autre amenée de courant, il se produit deux réductions en parallèle :Meanwhile, on the other current supply, two reductions occur in parallel:
• la réduction des protons selon : H+ + 1 e → ΛA H2 • the reduction of protons according to: H + + 1 e → Λ AH 2
• la réduction du sel selon : Pt2+ + 2 e → Pf• reduction of salt according to: Pt 2+ + 2 e → Pf
En terme de courant, la seconde réduction est négligeable devant la première.In terms of current, the second reduction is negligible in front of the first.
Pour imposer le courant prédéterminé à une température de 25°C, le générateur de courant G doit au moins imposer + 1 ,23 volt ou - 1 ,23 volt selon le sens de l'alternance en courant, ce qui correspond à la tension minimum de décomposition de l'eau et environ 0,2 volt par électrode en surtension plus une chute ohmique dans la membrane. Par conséquent, lors de l'inversion, la tension croît très vite avant de tendre vers un palier. Mais pendant la durée d'une alternance donnée, il se forme un peu d'hydrogène H2 d'un côté et un peu d'oxygène O2 de l'autre qui restent piégés au voisinage des amenées de courant.To impose the predetermined current at a temperature of 25 ° C, the current generator G must at least impose + 1, 23 volts or - 1, 23 volts in the direction of alternating current, which corresponds to the voltage minimum of water decomposition and about 0.2 volts per overvoltage electrode plus an ohmic drop in the membrane. Therefore, during the inversion, the voltage increases very quickly before reaching a landing. But during the duration of a given alternation, a small amount of hydrogen H 2 is formed on one side and a little oxygen O 2 on the other which remain trapped in the vicinity of the current leads.
A l'inversion suivante, le courant initial provient de la recombinaison inverse de l'électrolyse : l'hydrogène H2 donne des protons H+ et l'oxygène O2 est réduit en eau : la tension remonte finalement lentement. Puis, au fur et à mesure des alternances, la surface en platine de chaque face augmente, les surtensions diminuent et la tension monte de moins en moins vite vers une valeur d'équilibre de plus en plus basse. Progressivement, la tension de seuil n'est plus atteinte avant la fin de la période d'inversion.At the next inversion, the initial current comes from the inverse recombination of electrolysis: the hydrogen H 2 gives protons H + and the oxygen O 2 is reduced in water: the tension finally slowly rises again. Then, as and when alternating, the platinum surface of each side increases, overvoltages decrease and the voltage increases less and less quickly to a lower and lower equilibrium value. Gradually, the threshold voltage is no longer reached before the end of the inversion period.
La comparaison entre des dépôts réalisés selon un procédé classique sans modulation des durées d'inversion et des dépôts réalisés selon le procédé objet de l'invention est effectuée grâce à des courbes de tension (V) en fonction de la densité de courant (mA.cm"2) de la figure 5. Cette comparaison montre que le procédé permet de baisser la tension requise pour obtenir une densité de courant supérieure.The comparison between deposits made according to a conventional method without modulation of the inversion times and deposits made according to the method of the invention is performed by means of voltage curves (V) as a function of the current density (mA. cm "2 ) of Figure 5. This comparison shows that the method allows to lower the voltage required to obtain a higher current density.
L'invention ne se limite pas aux exemples précédemment décrits.The invention is not limited to the examples described above.
En effet, on pourra également envisager d'imposer des inversions de tension selon un courant de seuil.Indeed, it will also be possible to consider imposing voltage inversions according to a threshold current.
Le courant ou la tension appliqués pourront avoir une amplitude variable. La forme du signal pourra également être par exemple carrée, gaussienne... The applied current or voltage may have a variable amplitude. The signal form can also be square, Gaussian for example ...

Claims

Revendications claims
1. Procédé d'électrodéposition d'un métal sur un polymère échangeur d'ions pour l'obtention de cellules à électrodes-électrolyte polymère solide, caractérisé en ce qu'il comprend :1. A process for electroplating a metal on an ion-exchange polymer for obtaining solid polymer electrolyte-electrolyte cells, characterized in that it comprises:
- une phase d'imprégnation du polymère (M) par une solution d'ions métalliques pendant une période donnée de façon à ne faire entrer qu'un nombre d'ions nécessaires et suffisants pour effectuer le dépôt, ladite période étant déterminée en fonction de la profondeur de diffusion des ions tolérée,a phase of impregnation of the polymer (M) with a solution of metal ions during a given period so as to enter only a number of ions necessary and sufficient to effect the deposit, said period being determined as a function of the ion diffusion depth tolerated,
- une séquence permettant d'obtenir une succession d'ondes alternatives et dans laquelle chacun des cycles comprend les opérations suivantes : o l'application, à partir d'un temps to, aux électrodes (A1 , A2) de la cellule (CU) d'un courant (et/ou d'une tension) d'amplitude initiale prédéterminée présentant une première polarité de manière à réaliser une réduction électrochimique des ions localisés à l'interface du polymère (M) et de l'une desdites électrodes (A1), cette réduction engendrant un accroissement de la tension (et/ou une diminution du courant) aux bornes de la cellule CU, o la mesure de la tension (et/ou du courant) aux bornes de la cellule, o la mesure du temps s'écoulant à partir de l'instant t0, o la comparaison de la tension (et/ou du courant) mesurée avec une première tension (et/ou un premier courant) prédéterminée, o la comparaison du temps mesuré avec une période d'inversion prédéterminée, o l'inversion du courant (et/ou de la tension) à partir d'un instant t' avec l'application d'un courant (et/ou d'une tension) de même amplitude que l'amplitude initiale mais de polarité inversée, lorsque la tension (et/ou le courant) mesurée atteint ou dépasse la tension (et/ou s'abaisse au-dessous du courant) de seuil avant l'expiration de ladite période si la tension (et/ou le courant) de seuil n'a pas encore été atteinte sinon au moment de l'expiration de ladite période, o une nouvelle étape de mesure de la tension (ou du courant) aux bornes de la cellule, o une nouvelle mesure du temps s'écoulant à partir de l'instant t' d'inversion, o la comparaison de la tension (et/ou du courant) nouvellement mesurée avec une deuxième tension (et/ou un deuxième courant) de seuil pouvant présenter une même amplitude que la première tension (et/ou le premier courant) de seuil mais de polarité inversée, o l'inversion du courant (et/ou de la tension) avec l'application d'un courant (et/ou d'une tension) de même amplitude que l'amplitude initiale mais de polarité inversée par rapport au courant du cycle précédent, lorsque la tension (et/ou le courant) mesurée atteint ou dépasse la tension (et/ou s'abaisse au- dessous du courant) de seuil avant l'expiration de ladite période ou si la tension (et/ou le courant) de seuil n'a pas encore été atteinte sinon au moment de l'expiration de ladite période, o puis de nouveau les mesures de tension (et/ou de courant) et de temps, les comparaisons et les inversions de courant (et/ou de tension).a sequence making it possible to obtain a succession of alternative waves and in which each of the cycles comprises the following operations: the application, from a time to, to the electrodes (A1, A2) of the cell (CU) a current (and / or a voltage) of predetermined initial amplitude having a first polarity so as to achieve an electrochemical reduction of the ions located at the interface of the polymer (M) and one of said electrodes (A1 ), this reduction generating an increase in the voltage (and / or a decrease in current) at the terminals of the cell CU, where the measurement of the voltage (and / or the current) at the terminals of the cell, where the measurement of time flowing from the instant t 0 , where the comparison of the measured voltage (and / or current) with a predetermined first voltage (and / or a first current), where the comparison of the measured time with a period of predetermined inversion, where the inversion of the current (and / or the one) from a moment t 'with the application of a current (and / or a voltage) of the same amplitude as the initial amplitude but of inverted polarity, when the voltage (and / or the current) measured reaches or exceeds the threshold voltage (and / or falls below the current) before the expiry of that period if the voltage (and / or threshold current has not yet been reached, except at the expiry of said period, o a new step of measuring the voltage (or current) at the terminals of the cell, o a new measurement of the time s' flowing from the moment of inversion, where the comparison of the newly measured voltage (and / or current) with a second voltage (and / or a second current) of threshold may have the same amplitude as the first one. voltage (and / or the first current) threshold but inverted polarity, o the inversion of the current (and / or voltage) with the application of a current (and / or voltage) of the same amplitude that the initial amplitude but of reversed polarity with respect to the current of the preceding cycle, when the measured voltage (and / or current) reaches or exceeds the threshold voltage (and / or lowers below the current) before the expiration of said period or if threshold voltage (and / or current) has not yet been reached otherwise at the time of expiration of said period, o then again the voltage (and / or current) and time measurements, the comparisons and the current (and / or voltage) inversions.
2. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce qu'il comprend, en outre, après le dépôt présentant les caractéristiques souhaitées, l'application d'un courant continu afin de permettre aux ions restants s'il y en a de diffuser vers une interface polymère-électrode pour être réduits.2. electroplating process according to claim 1, characterized in that it comprises, in addition, after the deposit having the desired characteristics, the application of a direct current to allow the remaining ions if there are any to diffuse to a polymer-electrode interface to be reduced.
3. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que ledit polymère échangeur d'ions est une membrane échangeuse d'ions (M). 3. electrodeposition process according to claim 1, characterized in that said ion exchange polymer is an ion exchange membrane (M).
4. Procédé d'électrodéposition selon la revendication 3, caractérisé en ce que ladite membrane échangeuse d'ions est une membrane NAFION (marque déposée).4. electroplating process according to claim 3, characterized in that said ion exchange membrane is a NAFION membrane (registered trademark).
5. Procédé d'électrodéposition selon la revendication 3, caractérisé en ce que ladite membrane échangeuse d'ions est une membrane FLEMION (marque déposée).5. electroplating process according to claim 3, characterized in that said ion exchange membrane is a FLEMION membrane (registered trademark).
6. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que ledit métal est un des métaux suivants ou toute combinaison de mélange de ces métaux : platine, iridium, or, rhodium, ruthénium, palladium, argent, vanadium, chrome, fer, nickel, cobalt, cuivre, zinc, étain, antimoine, plomb, bismuth.6. electroplating process according to claim 1, characterized in that said metal is one of the following metals or any combination of these metals: platinum, iridium, gold, rhodium, ruthenium, palladium, silver, vanadium, chromium, iron , nickel, cobalt, copper, zinc, tin, antimony, lead, bismuth.
7. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que la détermination de la période d'inversion de l'onde est basée sur différents critères tels que l'épaisseur de la membrane, la nature du sel métallique, le temps de diffusion du sel métallique notamment en fonction de la nature du sel, de la température et de la pression.7. electroplating process according to claim 1, characterized in that the determination of the inversion period of the wave is based on various criteria such as the thickness of the membrane, the nature of the metal salt, the time of diffusion of the metal salt in particular according to the nature of the salt, the temperature and the pressure.
8. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que la valeur de la tension (ou du courant) de seuil dépend de la valeur d'amplitude en courant (ou en tension) choisie pour la succession d'ondes alternatives.8. electroplating process according to claim 1, characterized in that the value of the threshold voltage (or current) depends on the current amplitude value (or voltage) chosen for the succession of alternative waves.
9. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que l'amplitude en courant (ou en tension) est constante.9. Electroplating process according to claim 1, characterized in that the current amplitude (or voltage) is constant.
10. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que l'amplitude en courant (ou en tension) est variable.10. electroplating process according to claim 1, characterized in that the current amplitude (or voltage) is variable.
11. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que l'application du courant (ou de la tension) aux bornes de la cellule et les inversions de courant (ou de tension) sont réalisés par un générateur de courant alternatif (G) (ou un générateur de tension alternative).11. electroplating process according to claim 1, characterized in that the application of the current (or voltage) to the terminals of the cell and the current reversals (or voltage) are performed by a alternating current generator (G) (or alternating voltage generator).
12. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que le polymère est re-imprégné dans une solution d'ions métalliques identiques.12. electroplating process according to claim 1, characterized in that the polymer is re-impregnated in a solution of identical metal ions.
13. Procédé d'électrodéposition selon la revendication 1, caractérisé en ce que le polymère est re-imprégné dans une solution d'ions métalliques différents.13. electroplating process according to claim 1, characterized in that the polymer is re-impregnated in a solution of different metal ions.
14. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que la solution contient des ions métalliques différents afin d'effectuer une codéposition simultanée de plusieurs métaux.14. electroplating process according to claim 1, characterized in that the solution contains different metal ions in order to perform a simultaneous codéposition of several metals.
15. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que le dépôt métallique est effectué symétriquement sur les différentes faces d'un polymère.15. electroplating process according to claim 1, characterized in that the metal deposition is carried out symmetrically on the different faces of a polymer.
16. Procédé d'électrodéposition selon la revendication 1 , caractérisé en ce que le dépôt métallique est effectué dissymétriquement sur les différentes faces d'un polymère.16. Electroplating process according to claim 1, characterized in that the metal deposition is carried out asymmetrically on the different faces of a polymer.
17. Cellule à électrodes-électrolyte polymère solide obtenue conformément au procédé selon l'une des revendications précédentes, cette cellule comportant un polymère comprenant un dépôt très localisé, très rugueux formé des nano-grains de métal percolants dont la structure répond à un modèle fractal.17. A solid polymer electrolyte-electrolyte cell obtained according to the method according to one of the preceding claims, this cell comprising a polymer comprising a highly localized, very rough deposit formed of percolating metal nano-grains whose structure responds to a fractal model. .
18. Cellule selon la revendication 17, caractérisée en ce que le dépôt a une épaisseur 0,01 et 10 microns et de préférence entre 0,01 et 0,1 micron. 18. Cell according to claim 17, characterized in that the deposit has a thickness of 0.01 and 10 microns and preferably between 0.01 and 0.1 micron.
19. Cellule selon la revendication 17, caractérisée en ce que le dépôt a une épaisseur inférieure à 0,01 micron. 19. Cell according to claim 17, characterized in that the deposit has a thickness of less than 0.01 micron.
EP05850580A 2004-12-20 2005-12-19 Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte Not-in-force EP1838903B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0413586A FR2879626B1 (en) 2004-12-20 2004-12-20 METHOD FOR ELECTRODEPOSITION OF A METAL FOR OBTAINING SOLID POLYMERIC ELECTRODE ELECTROLYTE CELLS
PCT/FR2005/003239 WO2006067337A2 (en) 2004-12-20 2005-12-19 Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte

Publications (2)

Publication Number Publication Date
EP1838903A2 true EP1838903A2 (en) 2007-10-03
EP1838903B1 EP1838903B1 (en) 2010-08-25

Family

ID=34954111

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05850580A Not-in-force EP1838903B1 (en) 2004-12-20 2005-12-19 Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte

Country Status (5)

Country Link
EP (1) EP1838903B1 (en)
AT (1) ATE478982T1 (en)
DE (1) DE602005023214D1 (en)
FR (1) FR2879626B1 (en)
WO (1) WO2006067337A2 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5949696B2 (en) * 2013-08-07 2016-07-13 トヨタ自動車株式会社 Metal film forming apparatus and film forming method
JP5915602B2 (en) 2013-08-07 2016-05-11 トヨタ自動車株式会社 Metal film forming apparatus and film forming method
CN110607466A (en) * 2018-06-14 2019-12-24 Bgt材料有限公司 Method for manufacturing graphene-lead alloy

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH634881A5 (en) * 1978-04-14 1983-02-28 Bbc Brown Boveri & Cie METHOD FOR ELECTROLYTICALLY DEPOSITING METALS.
CH663221A5 (en) * 1984-01-26 1987-11-30 Bbc Brown Boveri & Cie METHOD FOR CONTINUOUSLY COATING A SOLID ELECTROLYTE WITH A CATALYTICALLY ACTIVE METAL.
US6258239B1 (en) * 1998-12-14 2001-07-10 Ballard Power Systems Inc. Process for the manufacture of an electrode for a solid polymer fuel cell

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2006067337A2 *

Also Published As

Publication number Publication date
WO2006067337A2 (en) 2006-06-29
FR2879626A1 (en) 2006-06-23
EP1838903B1 (en) 2010-08-25
ATE478982T1 (en) 2010-09-15
WO2006067337A3 (en) 2007-05-24
DE602005023214D1 (en) 2010-10-07
FR2879626B1 (en) 2007-02-23

Similar Documents

Publication Publication Date Title
Delime et al. Enhancement of the electrooxidation of ethanol on a Pt–PEM electrode modified by tin. Part I: Half cell study
Giordano et al. High performance fuel cell based on phosphotungstic acid as proton conducting electrolyte
Frelink et al. Ellipsometry and dems study of the electrooxidation of methanol at Pt and Ru-and Sn-promoted Pt
Watanabe et al. Electrocatalysis by ad-atoms: Part XIII. Preparation of ad-electrodes with tin ad-atoms for methanol, formaldehyde and formic acid fuel cells
Le Vot et al. Study of the electrochemical oxidation of ammonia on platinum in alkaline solution: Effect of electrodeposition potential on the activity of platinum
Alfred Co-deposited Pt–WO 3 electrodes. Part 1.—Methanol oxidation and in situ FTIR studies
EP2680353B1 (en) Hollow platinum nanoparticles for fuel cells
EP2837051A1 (en) Fuel cell device with electrolytes flowing by means of percolation through electrodes having a porous, three-dimensional structure
EP1838903B1 (en) Method for electroplating a metal to obtain cells with electrodes-solid polymer electrolyte
EP2824219A1 (en) Method for producing a metal foam, metal foam, uses thereof and device including such a metal foam
EP2922987B1 (en) Method for coating the surface of an organic or metal material with particular organic compounds by means of a pulsed-current electrochemical reduction of the diazonium ions of said organic compounds
Takahashi et al. Electrochemically reduced Pt oxide thin film as a highly active electrocatalyst for direct ethanol alkaline fuel cell
EP2768055A1 (en) Bipolar metal plate for fuel cell with proton exchange membrane
FR2624885A1 (en) Electrodes-solid polymeric electrolyte system usable, for example, for the electrolysis of water, and process for its manufacture
EP2702190B1 (en) Process of growth of metallic particles by electrodeposition with in situ inhibition
Genthe et al. Long‐Term Performance of a Zinc–Silver/Air Hybrid Flow Battery with a Bifunctional Gas‐Diffusion Electrode at High Current Density
WO2015024714A1 (en) Active layer/membrane arrangement for a hydrogen production device and assembly comprising said arrangement suitable for a porous current collector and method for producing the arrangement
JP2005105409A (en) Method for manufacturing porous silicon structure and method for manufacturing metal-carrying porous silicon
MacHardy et al. The diffusion coefficient of Cu (II) ions in sulfuric acid–aqueous and methanesulfonic acid–methanol solutions
US20090145781A1 (en) Method of treating nanoparticles using a proton exchange membrane and liquid electrolyte cell
EP2452388B1 (en) Method and device for increasing the lifespan of a proton exchange membrane fuel cell
CH623686A5 (en)
Dennison et al. An electrochemical and optical microscopic study of the reduction of HTeO2+ in aqueous acid solution
Yaniv et al. Electrodeposition and stripping at graphite cloth electrodes in a flow-through cell
Kim et al. Hanging meniscus configuration for characterizing oxygen-reduction electrocatalysts in highly concentrated electrolytes

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20070625

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20080516

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: FRENCH

REF Corresponds to:

Ref document number: 602005023214

Country of ref document: DE

Date of ref document: 20101007

Kind code of ref document: P

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: CABINET MOUTARD

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20100825

LTIE Lt: invalidation of european patent or patent extension

Effective date: 20100825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101225

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101125

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101227

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101126

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20101228

Year of fee payment: 6

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20101206

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101231

26N No opposition filed

Effective date: 20110526

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602005023214

Country of ref document: DE

Effective date: 20110526

REG Reference to a national code

Ref country code: CH

Ref legal event code: PFA

Owner name: UNIVERSITE PARIS-SUD (PARIS XI)

Free format text: UNIVERSITE PARIS-SUD (PARIS XI)#15, RUE GEORGES CLEMENCEAU#91405 ORSAY CEDEX (FR) $ COMPAGNIE EUROPEENNE DES TECHNOLOGIES DE L'HYDROGENE (CETH)#INNOV' VALLEY ENTREPRISES - BATIMENT DO ROUTE DE NOZAY#91460 MARCOUSSIS (FR) -TRANSFER TO- UNIVERSITE PARIS-SUD (PARIS XI)#15, RUE GEORGES CLEMENCEAU#91405 ORSAY CEDEX (FR) $ COMPAGNIE EUROPEENNE DES TECHNOLOGIES DE L'HYDROGENE (CETH)#INNOV' VALLEY ENTREPRISES - BATIMENT DO ROUTE DE NOZAY#91460 MARCOUSSIS (FR)

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20110226

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101219

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20100825

REG Reference to a national code

Ref country code: CH

Ref legal event code: PCAR

Free format text: NEW ADDRESS: RUE DE LYON 75 - 4EME ETAGE, 1203 GENEVE (CH)

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 11

REG Reference to a national code

Ref country code: CH

Ref legal event code: PCAR

Free format text: NEW ADDRESS: BOULEVARD GEORGES-FAVON 3 (1ER ETAGE), 1204 GENEVE (CH)

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 12

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 13

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20201217

Year of fee payment: 16

Ref country code: IT

Payment date: 20201210

Year of fee payment: 16

Ref country code: FR

Payment date: 20201008

Year of fee payment: 16

Ref country code: CH

Payment date: 20201102

Year of fee payment: 16

Ref country code: DE

Payment date: 20201209

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20201013

Year of fee payment: 16

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602005023214

Country of ref document: DE

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20211219

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20211231

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211219

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220701

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211231

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211231

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211231

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211231

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20211219