FR3031625A1 - METHOD FOR MANUFACTURING A NEGATIVE ELECTRODE BY COMPRESSION OF A METAL PASTE AND FOAM FOR AN ELECTRIC ENERGY STORAGE DEVICE - Google Patents

Abstract

A method of manufacturing a negative electrode (EN) for an electrical energy storage device (DS) comprises a first step of pressing a paste containing a first alkali metal against a porous foam containing a second metal, for obtaining a first intermediate element in which the first alkali metal is impregnated into pores of the second metal, a second step of heating the first intermediate element to pyrolize its non-metallic compounds and obtain a second intermediate element, a third step of treating the second intermediate element; second intermediate element to define a first portion (P1), poor in first alkali metal and adapted to the diffusion of an electrolyte, and a second portion (P2), rich in first alkali metal and defining an active zone, and a fourth step of impregnating the second portion (P2) of a basic gel containing a conductive polymer anionic.

Description

TECHNICAL FIELD The invention relates to devices for storing electric energy of the so-called alkaline-air metal type. , and the manufacture of negative electrodes for equipping such devices. As known to those skilled in the art, an electrical energy storage device of the so-called alkaline-air type, such as for example an aluminum-air cell (denoted Al-air), is an alkaline electrochemical generator based on a controlled reaction, between the alkali metal (for example aluminum) and oxygen (or O 2), generally present in the air, which produces electricity. It will be noted that it constitutes an electrochemical storage and not an electrochemical converter because the aluminum (or alkali metal) is included in the core of each cell of the Al-air cell and is gradually consumed (the Al-air cell ceases to discharge current when useful aluminum is consumed in full). Its autonomy is therefore conditioned by the amount of useful aluminum that includes each of its cells.

Schematically, an Al-air cell consists of a negative electrode consisting of a solid aluminum plate, a plane air positive electrode and consisting of several layers of porous carbon allowing the reduction of the oxygen contained in the air, and a liquid alkaline electrolyte (such as KOH liquid potash) flowing between the negative and positive electrodes. The electrochemical reaction taking place at the positive electrolyte electrode interface during a discharge consists of a reduction of oxygen: O 2 + 2H 2 O + 4e = 40H- (standard potential E 0 = 0.4 V / ENH). It is the solubilized oxygen which is reduced and not the 02 in the form of gas. The oxygen is distributed from the outside as a gas and diffuses in the diffusion layer (or GDL ("Gas Diffusion Layer")) of the positive electrode, up to the active layer of the latter (place of reduction electrochemical), which comprises catalysts (such as, for example, Pt and MnOx) distributed on the porous carbon. The electrochemical reaction taking place at the negative electrode-electrolyte interface during a discharge consists of an oxidation of aluminum: Al 5 + 30H- = Al (OH) 3 + 3e- (standard potential E ° = -2, 31 V / ENH). During a discharge, the aluminum of the negative electrode is gradually consumed according to an electrochemical oxidation which leads to the formation of aluminum hydroxides Al (OH) 3. In a strongly basic medium, these hydroxides are present in the form of Al (OH) 4- aluminate ions, which polymerize when concentrated. This leads to the formation of a reaction product having the consistency of a gel. This results in an overall balance sheet: 4AI + 302 + 6H20 = 4A1 (OH) 3, which in theory makes it possible to obtain a standard no-load voltage of 2.7 V for each cell.

In theory this type of electrical energy storage device has a very high energy density (typically 6 to 8 kWh / kg for each cell), which is much higher than that offered by existing batteries (in particularly those of the Li-ion type). However, there are a number of limitations in that they currently have actual energy densities that are much lower than those predicted by the theory (typically 1 to 2 kWh / kg for each cell). Indeed, the electrolyte flows on the surface of the electrodes in the manner of a cascade of water, which induces a more or less homogeneous distribution of the electrolyte on the active surface of the electrodes and the need to respect a positioning particular device during its integration into a system, such as a vehicle. In addition, the circulating electrolyte closed loop, it is gradually loaded aluminates, and can quickly become the consistency of a molasses that complicates the interventions within the device.

Furthermore, in practice the no-load voltage is of the order of 1.2 V due to overvoltages which, moreover, induce losses of power and energy. These overvoltages occur mainly at the level of the negative electrode because it is massive (aluminum plate), and therefore its surface in contact with the electrolyte is not totally homogeneous (presence of impurities and of dust), which induces an inhomogeneous progressive consumption, an impossibility of using it integrally, and a progressive weakening. In addition, aluminate gels are gradually formed on the negative electrode during discharges, and these aluminate gels are partially washed away by the circulating aqueous electrolyte, which makes it more and more viscous and therefore induces a progressive fouling of the pumps that circulate it and therefore poorer anionic conductivity and poorer thermal property. This results in an acceleration of performance losses and therefore a reduction in the service life. Finally, the Al-air cells are not rechargeable because of the respective constitutions of the positive air electrode and the negative electrode. Indeed, the air positive electrode being composed of porous carbon its recharge would be to oxidize the OH- ions to O2 in a reverse reaction to the reduction of oxygen present above, which would induce premature aging due to a rapid embrittlement. In addition, the refills should induce a reduction of aluminum aluminate gel, which is thermodynamically very difficult to obtain and therefore practically unrealizable. The invention is therefore particularly intended to improve the situation. In particular, it proposes a method for producing a negative electrode for equipping an electrical energy storage device, and comprising: a first step in which a paste containing a first alkali metal is pressed against a porous foam containing a second metal, to obtain a first intermediate element in which the first alkali metal is impregnated in pores of the second metal, - a second step in which the first intermediate element is heated in order to pyrolize chemical and organic compounds it comprises a third step in which the second intermediate element is treated in order to define a first portion, which is poor in the first alkali metal and which defines a diffusion zone for an electrolyte, and a second portion, rich in first alkali metal and defining an active zone, and - a fourth step in which the second part of a basic gel containing an anionic conductive polymer is impregnated to obtain the negative electrode.

This makes it possible to simplify and facilitate the implementation of the manufacturing steps of the negative electrode, and thus to induce a reduction in costs, but also to significantly increase the intrinsic performances (power density and energy density). maximum) and the service life of the negative electrodes.

The manufacturing method according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular: the first alkali metal may be aluminum; the paste may result from a mixture of a powder containing aluminum and nickel, an ammonium salt, and a chemically amorphous polymeric binder containing water; in the third step, the second intermediate element can be treated according to a method known as Raney; the second metal may be nickel; In the first step cold pressing can be carried out; in the second step, the first intermediate element can be heated at a temperature of between about 360 ° C. and about 440 ° C., for a duration of between about 50 minutes and about 140 minutes.

The invention also proposes an electrical energy storage device comprising at least one cell comprising a negative electrode produced by means of a manufacturing method of the type of the one presented above and supplied with electrolyte, a positive electrode. air-fed air and water, and an anionic membrane interposed closely between the negative electrode and positive air electrode. For example, the air positive electrode of each cell may comprise porous carbon. Furthermore, this device may comprise at least two cells mounted in series with the interposition of at least one bipolar plate which provides electrical and thermal conduction and which is arranged to supply electrolyte to the negative electrodes of the neighboring cells and to air 10 and water the air positive electrodes of these neighboring cells. Other features and advantages of the invention will be apparent from the following detailed description and the accompanying drawings, in which: Figure 1 schematically illustrates in a perspective view the pressing of a paste; against a porous foam, intended to produce a first intermediate element during the first step of the manufacturing method according to the invention, FIG. 2 schematically illustrates, in a perspective view, the heating of the first intermediate element of FIG. to produce a second intermediate element in the second step of the manufacturing method according to the invention, Figure 3 schematically illustrates, in a perspective view, the treatment of the second intermediate element of Figure 2 to produce a third element. intermediate in the third step of the manufacturing method according to the invention, FIG. 4 schematically illustrates, in a e perspective view, the impregnation of the second portion of the third intermediate element of Figure 2 to produce a negative electrode in the fourth step of the manufacturing method according to the invention, and Figure 4 schematically and functionally illustrates , in a sectional view, an exemplary embodiment of an electrical energy storage device according to the invention.

The invention aims in particular to provide a method for enabling the manufacture of a negative electrode EN, itself intended to equip a DS electrical energy storage device. In what follows, it is considered, by way of non-limiting example, that the DS electrical energy storage device is intended to equip a vehicle, possibly of automotive type. But the invention is not limited to this application. It concerns any system, device, installation or building that can be equipped with at least one electrical energy storage device. Thus, it concerns vehicles (land, sea 10 (or fluvial), and air), facilities (including those of industrial type), and buildings (buildings, houses and theaters). The method of manufacturing negative electrodes EN according to the invention comprises four steps. In a first step, illustrated in FIG. 1, a PA paste containing a first alkali metal is pressed against an MP porous foam containing a second metal, in order to obtain a first intermediate element E1 in which the first alkali metal is impregnated in pores of the second metal. In what follows, it is considered, by way of non-limiting example, that the first alkali metal is aluminum (AI). But the invention is not limited to this type of alkali metal. It concerns indeed any alkali metal that can be part of a negative electrode EN to participate in an electrochemical oxidation reaction to participate in the production of electricity. In this case, the PA paste may result from a mixture of a powder containing aluminum and nickel (Ni), an ammonium salt, and a chemically amorphous polymeric binder containing the water. The aluminum content must be high because it is the latter (AI) that will be consumed in future electrochemical oxidation reactions. For example, the ammonium salt, which is here intended to promote porosity, may be ammonium bicarbonate.

Also for example, the chemically amorphous polymeric binder may be PTFE (polytetrafluoroethylene). It will be noted that the respective concentrations of the different elements constituting the paste PA can be modulated according to the compactness desired for the desired use. Moreover, PA paste can be easily prepared with mechanical mixers. Furthermore, it is considered in the following, by way of non-limiting example, that the second metal is nickel. But the invention is not limited to this type of metal. It relates in fact to any metal that may be part of a porous foam intended to serve as a support, particularly internally (in its pores), for particles of first alkali metal. The porous foam MP nickel may be pure nickel or an alloy derived from, for example, stainless steel or inconel O. Nickel-based materials are advantageous to use because they are very resistant to corrosion. aqueous and acid-base, and when in the form of a porous foam, they can be easily compressed keeping their porous character (including when using a mechanical press (or a "roller") , and allow easy control of their thickness after compression.Nickel-based metals are very good thermal and electrical conductors.The dimensions of the porous foam MP depend on the desired surface area and the desired thickness. For example, and not limitation, this thickness may be between about 0.1 mm and about 10 mm.It will be noted that in the first step the pressing is preferably cold, by example by means of a mechanical press (whose action is shown by the arrows Fl and F1 'in Figure 1).

It will be understood that the pressing operation is intended to penetrate the mixture containing (here) the Al-Ni alloy within the pores of the porous foam MP. This Al-Ni alloy shrinks and adheres strongly to the nickel foam, and thus the PA paste is evenly distributed throughout the volume of the pressed nickel foam. The amount of PA paste required per given volume of porous foam MP depends on the desired surfaces and thicknesses for the negative electrode EN at the end of the manufacturing process. In the end, the first intermediate element El may optionally have a thickness ten times smaller (or even more) 3031625 8 than that presented by the porous foam MP before pressing. In a second step, illustrated in FIG. 2, the first intermediate element E1 is heated in order to pyrolize the chemical and organic compounds that it comprises and to obtain a second intermediate element E2 comprising the metals (contained in the first intermediate element El). To do this, one can, for example, use an exhaust recovery furnace. For example, and not limited to, the first intermediate element E1 can be heated to a temperature of between about 360 ° C and about 440 ° C, and for a time of between about 50 minutes and about 140 minutes. In practice, an optimal temperature and duration are chosen according to the operating conditions (such as, for example, the quantity of pulp PA, the composition of the pulp PA, the thickness of the porous foam MP and the constitution of the latter (MP )). By way of example, it can be heated to about 400 ° C for about 90 minutes. These values are well adapted to the example that is considered here. Indeed, PTFE has a melting temperature of 327 ° C, ammonium bicarbonate has a melting temperature of the order of 35 ° C to 60 ° C while nickel and aluminum have melting temperatures above 1000 ° C (and therefore are not denatured by the above pyrolysis temperatures). It will be noted that the second intermediate element E2, which results from the heating of the first intermediate element E1, contains almost only the metals (here Al and Ni), and the Al-Ni alloy is found finely distributed in the pores of the matrix. based on nickel resulting from pressing. This second intermediate element E2 is a very good electrical and thermal conductor and has a very good resistance to acid-base corrosion because its matrix is nickel-based. In a third step, illustrated in FIG. 3, the second intermediate element E2 is treated in order to define a first part P1, poor in first alkali metal and which defines a diffusion zone for an electrolyte, and a second part P2, rich first alkali metal and which defines an active zone for an electrochemical oxidation reaction of the first alkali metal (here aluminum). At the end of this treatment, a third intermediate element E3 is obtained. When the second intermediate element E2 is aluminum-based, it can be treated in the third step by implementing a method called Raney, well known to those skilled in the art. This method of selective corrosion attack is well adapted to obtaining a first portion P1, poor in first alkali metal (here aluminum) and defining a diffusion zone for the future electrolyte, and a second part P2, rich in first alkali metal and defining an active zone for the electrochemical oxidation reactions of the first alkali metal.

The Raney method applied to the example considered here is described below. The Al-Ni alloy is selectively dissolved according to a leaching reaction corresponding in a simplified manner to the following formula: NiAl (s) + OH- (aq) + H20 (1) = Ni Raney + A102- (aq) + 3 / 2H 2 (g) where (s) denotes the solid phase, (aq) denotes the aqueous phase, (I) denotes the liquid phase, and (g) denotes the gas phase. Preferably, the basic attack is carried out with a concentrated solution and in excess of alkali hydroxide (typically 20 to 30% by weight for sodium hydroxide). Indeed, for low pH the formed aluminates precipitate in the form of bayerite which blocks access to the porosity and covers the surface of the negative electrode EN. The temperature at which the leaching of the Al-Ni alloy takes place should be in the order of 70 ° C to 100 ° C to avoid negatively impacting the specific surface area of Raney nickel (Ni Raney) Raney). . It will be noted that part of the hydrogen gas (H2) formed in the above formula is absorbed in the microporosity of Raney nickel.

The dissolution of the aluminum can be controlled in the thickness of the second intermediate element E2 as a function of the height of the part which is immersed in the sodium hydroxide. The concentration of hydroxide (OH-) and the soaking time influencing the progress of leaching, it is possible to obtain Raney nickels with specific surfaces and amounts of aluminum higher or lower. For example, the first part P1 of the second intermediate element E2 can be dipped in a highly concentrated aqueous solution of sodium hydroxide (typically 5 to 10 M NaOH), in order to minimize the amount of aluminum remaining in the pores while keeping an acceptable porosity to ensure good diffusion of hydroxides in the heart of the future CS cell in operation. The second part P2 of the second intermediate element E2 can be soaked in a concentrated alkaline solution (typically sodium hydroxide or concentrated potassium hydroxide). This second part P2 being intended to be the active layer of the negative electrode EN (rich in aluminum), the leaching parameters used to treat it are modified compared to those used for the first part P1.

To do this, it is possible to reduce the soaking time or even the concentration of hydroxide ions. After each leaching it is preferable to rinse with water the second intermediate element E2, in order to remove all traces of sodium hydroxide and aluminate, and then to dry it at about 200 ° C. to reduce all traces of water.

It will be appreciated that if the porosity of the second portion P2 of the second intermediate element E2 is initially sufficient, it may not be leached. It will also be noted that it is preferable to handle, under an inert atmosphere, the third intermediate element E3 resulting from the treatment of the second intermediate element E2, so as to avoid any risk of ignition in contact with the air and not to oxidize the part. Raney nickel (because it would reduce the active surface of the catalytic layer due to the formation of a passivation layer of electrically non-conductive oxides blocking the pores).

It will also be noted that the first portion P1 of the third intermediate element E3 can partially corrode over time due to the presence of hydroxide ions in a zone containing a small amount of aluminum. However, this has no effect on the electrical conductivity nor on the physicochemical properties of the first part P1 since nickel is largely in the majority. It will also be noted that the first portion P1 of the third intermediate element E3 may be optionally abraded so as to optimize the electrical contacts with a bipolar plate of its future cell CS (acting as current collector and distribution of hydroxide ions ). However, such an abrasion must be mastered so as to allow efficient diffusion of the hydroxide ions from the outside to the second portion P2 of the third intermediate element E3. In a fourth step, illustrated in FIG. 4, the second portion P2 of the third intermediate element E3 is impregnated with a basic gel that contains an anionic conducting polymer, in order to obtain a negative electrode EN ready to be integrated in a CS cell. a device 1 o DS electrical energy storage. This fourth step also preferably takes place under an inert atmosphere. The basic gel may be a gel of a strongly basic ionomer solution of an anionic conductive polymer, such as, for example, styrene, alkyl or polyvinyl alcohol. Note that the impregnation of the only second part P2 can be done by different techniques, such as for example by spraying or coating. Furthermore, the impregnation is preferably in liquid form to be effective in a maximum of pores.

It will also be noted that after the impregnation it is also possible to carry out a crosslinking (or formation of interpenetrating networks) intended to optimize the ion exchange, at the heart of the future CS cell in operation, between the second part P2 of the negative electrode EN and the anionic membrane MA (described later). For this purpose, for example, a chemical crosslinking agent and / or a thermal crosslinking agent may be used. Crosslinking is mainly intended to form interpenetrating networks (similar to a wool ball), to improve the mechanical strength while ensuring good ionic conduction. It will also be noted that in order to facilitate the preferential impregnation of the anionic conductive polymer in the second portion P2 of the third intermediate element E3, the microporosity of the latter (P2) is less than that of the first portion P1 of the third intermediate element E3. It will also be noted that in the embodiment illustrated in non-limiting manner in FIGS. 3 to 5, the thickness of the first portion P1 is smaller than that of the second portion P2. But the opposite situation is also possible if it allows to minimize the overvoltages induced by the diffusion of the electrolyte in a finer porosity. As mentioned above, the invention also proposes using the negative electrodes EN, produced by means of the manufacturing method described above, within CS cells equipping DS electrical energy storage devices. A non-limiting example of an electrical energy storage device DS, according to the invention, is illustrated in FIG. 5. As illustrated, a device (for storing electrical energy) DS, according to the invention, comprises at least one CS cell intended to produce electricity. Each cell CS 15 comprises a negative electrode EN, produced by means of the manufacturing method previously described and supplied with electrolyte, an air positive electrode EP, supplied with air (O 2) and with water (H 2 O), and an anionic membrane MA, interposed closely between the negative electrode EN and the positive air electrode EP. It is important to note that the anionic membrane MA is in contact with the second part P2 of the negative electrode EN, and that the first part P1 of this negative electrode EN is supplied with electrolyte (for example a solution of potassium hydroxide (or KOH)). This results in a solid CS cell "core" that is significantly easier to assemble and store, significantly easier to install in a DS device, and significantly easier to replace. In addition, it allows fairly thin thicknesses (typically 0.5 mm to 1 mm or less) and therefore high compactness. It will also be noted that in the nonlimiting example illustrated in FIG. 5 the device DS comprises only one cell CS. But it could comprise at least two CS cells mounted in series with the interposition of at least one bipolar plate providing electrical and thermal conduction and arranged to supply electrolyte to the negative electrodes EN of neighboring cells and to air and water the positive electrodes. to air EP 3031625 13 of these same neighboring cells. In the case of a unit cell, the electrodes EN and EP are powered by monopolar plates (having a single active distribution face). For example, the positive air electrode EP may comprise porous carbon. More specifically, it may comprise a first subpart P3 made of carbon fiber sheets and defining a diffusion layer (or GDL (Gas Diffusion Layer)), and a second subpart P2 consisting of at least one layer of porous carbon allowing the reduction of the oxygen contained in the air (and thus the seat of the electrochemical reactions). As illustrated, the device DS preferably comprises first and second receptacle R2s. The first receptacle R1 comprises an inlet and an outlet connected to an air and water supply circuit (arrows F2 and F3), and an inner face open and in contact with the first sub-portion P3 of the positive electrode. to air EP to supply the latter (EP) in air and water (arrow F4) and to collect in the latter (EP) the excess air and water (arrow F5). The second receptacle R2 comprises an input and an output connected to an electrolyte supply circuit (arrows F6 and F7), and an inner face open and in contact with the first part P1 of the negative electrode EN to supply the latter. (EN) electrolyte (arrow F8) and to collect in the latter (EN) hydroxide ions OH- (arrow F9). In a CS cell of a multicellular DS device, the hydroxide ions are distributed on the surface of the negative electrode EN, and more precisely on the first portion P1 which is in electrical contact with the anode portion of the bipolar plate. cells. Their circulation is forced on the surface of this negative electrode EN. The first part P1 is hydrophobic (because it is made of metal (Ni)), which limits the risks of flooding. Part of the hydroxide ions diffuse through the second part P2 (active layer) which is the seat of the anodic oxidation of aluminum and whose character is more hydrophilic. Structurally, the second portion P2 (active layer) has an active developed surface much larger than a solid aluminum plate for which the active surface is approximately equal to the geometrical surface. As a result, the power density offered is potentially higher with equal amounts of embedded aluminum, and the energy density is also greater because of the greater proportion of accessible aluminum that can be oxidized compared to embedded aluminum. It will also be noted that the electric power delivered by a cell CS can be controlled by acting on the air and hydroxide flows. During a discharge, the positive air electrode EP provides the reduction of O 2 according to the reaction: O 2 + 2H 2 O + 4e = 40H- (standard potential E 0 = 0.4 V / ENH). Note that it is preferable that the air (or the pure oxygen (02)) is moistened to have good reaction kinetics. The hydroxide ions (OH-) produced by this reaction pass through the anionic membrane MA and then into the second part P2 of the negative electrode EN (arrows F10). On the other hand, during a discharge, the finely dispersed aluminum in the second part P2 is oxidized according to the reaction: Al + 30H- = Al (OH) 3 + 3e- (standard potential E ° = -2.31 V / ENH). The aluminates formed are present in the form of aluminate ions Al (OH) 4- because the environment is strongly basic. These aluminate ions are "trapped" in the polymer structure and remain largely in the second part P2, where they tend to polymerize. A small amount of formed aluminate ions can be entrained by the circulating electrolyte via the first part P1 (diffusion layer), where it can be mainly "trapped". Thus, few aluminate ions circulate in the electrolyte supply circuit, which considerably limits the progressive pollution of the latter. In order to prevent the negative electrode EN from gradually charging with aluminate ions, which could lead to a reduction in the porosities of its diffusion layer P1 and active layer P2, and consequently to reduce the performance, it is possible to carry out occasionally load phases. This can in fact make it possible to avoid this progressive loading, or even to allow partial regeneration of the active aluminum, because the aluminate ions formed remain partly in the vicinity of the active sites. The invention offers several advantages, among which: - a simplified management of the electrolyte in the electrical energy storage device due to its circulation via the outside of the cell core, - a simplified maintenance of the storage device of electrical energy, - simplification and ease of implementation of the steps of manufacturing the negative electrode, which leads to a reduction of costs, - an increase in intrinsic performance (maximum power density and maximum energy density ) and the life of the negative electrode, - easier handling because of the solid nature of the heart of each cell, - an improvement in the compactness of the electrical energy storage device due to the solid nature of the heart of each cell, 15 - a good control of the thickness of the negative electrode, which makes it possible to adapt the performances to the targeted application, - a great resistance of the negative electrode to aqueous and acid-base corrosion, a possibility of optimizing the electronic and thermal conductivities of the negative electrode.

Claims (10)

REVENDICATIONS1. A method of manufacturing a negative electrode (EN) for an electrical energy storage device (DS), characterized in that it comprises a first step in which a paste (PA) containing a first alkali metal is pressed against a porous foam (MP) containing a second metal, to obtain a first intermediate element (El) in which said first alkali metal is impregnated in pores of said second metal, a second step in which said first intermediate element (El) is heated to pyrolizing chemical and organic compounds it comprises and obtaining a second intermediate element (E2) comprising the metals, a third step in which said second intermediate element (E2) is treated in order to define a first part (P1), First alkali metal and defining a diffusion zone for an electrolyte, and a second portion (P2), rich in first alkali metal and defining an active zone, and a fourth step in which said second portion (P2) is impregnated with a basic gel containing an anionic conducting polymer to obtain said negative electrode (EN). 20 2. Method according to claim 1, characterized in that said first alkali metal is aluminum. 3. Method according to claim 2, characterized in that said paste (PA) results from a mixture of a powder containing said aluminum and nickel, an ammonium salt, and a chemically amorphous polymer binder and 25 containing water. 4. Method according to one of claims 2 and 3, characterized in that in said third step is treated said second intermediate element (E2) according to a method called Raney. 5. Method according to one of claims 1 to 4, characterized in that said second metal is nickel. 6. Method according to one of claims 1 to 5, characterized in that in said first step is carried out cold pressing. 7. Method according to one of claims 1 to 6, characterized in that 3031625 17 in said second step is heated said first intermediate element (El) at a temperature between about 360 ° C and about 440 ° C, for a period from about 50 minutes to about 140 minutes. 5 8. An electrical energy storage device (DS), characterized in that it comprises at least one cell (CS) comprising a negative electrode (EN) produced by means of the manufacturing method according to one of claims 1 to 7 and electrolyte fed, an air positive electrode (EP) fed with air and water, and an anionic membrane (AM) interposed closely between said negative electrode (EN) and positive air electrode (EP). 9. Device according to claim 8, characterized in that said positive air electrode (EP) comprises porous carbon. 10. Device according to one of claims 8 and 9, characterized in that it comprises at least two cells (CS) mounted in series with the interposition of at least one bipolar plate providing electrical and thermal conduction and arranged to supply power. electrolyte the negative electrodes (EN) of neighboring cells and in air and water the positive air electrodes (EP) of neighboring cells.