Battery with improved electrolyte and improved electrodes

Abstract

The description relates to a battery device comprising: - electrodes comprising an anode and a cathode; and - an electrolyte, between the electrodes, comprising a crystalline material having the composition M2B2O5.x(HOH).y(NOH), where M and N are alkaline elements or hydrogen, or mixtures of alkaline elements or hydrogen, B is titanium, O and H denote the elements oxygen and hydrogen, respectively, and x and y are between 0 and 4 and denote the presence of H+, OH-, N+ ions, which are capable of migrating into the crystalline material. In particular, at least one type of ion from among H+, OH-, N+ and M+ is movable so as to migrate into the crystalline material towards at least one of the electrodes, and the at least one of the electrodes is made of a material capable of carrying out a chemical interaction with at least one of the H+, OH-, M+ and N+ ions.

Description

Description Title: Battery with improved electrolyte and electrodes technical field

[0001] This disclosure relates to the field of batteries, both in the form of cells or fuel cells and rechargeable batteries. Previous technique

[0002] Document WO-2018 / 060656 presented a particularly promising material for forming the electrolyte of a supercapacitor. This material is a solid crystalline structure with an A2B2O5 structure, where A can be an alkali metal and B can be titanium. The performance of this material led the inventors named in this document to consider its application as a battery, which is discussed in the aforementioned document (specifically, page 12, lines 15-30, with reference to Figure 8).

[0003] Nevertheless, the embodiment presented aims to consider the entire electrolyte attached to the two electrodes as a "pseudo-battery" in the sense that the electrical discharge ("rapid, on the order of a few minutes, then relatively slow thereafter, on the order of a few hours") could not be perfectly controlled and jackets of piezoelectric elements PZ1, PZ2, PZ3, etc. remained necessary to mechanically constrain or relax the material in order to block or release the electrical charges.

[0004] Typically, the materials intended for the electrodes were carbon, or a metal such as copper, silver, gold, or platinum, simply to ensure electron collection. Summary

[0005] This disclosure improves the situation.

[0006] It proposes to keep a similar material for the electrolyte but to improve the materials chosen for the electrodes in order to better manage the charge / discharge of the device and to increase the energy density that can be stored, by involving a controlled chemical interaction between the material of an electrode and ions that can move in the material of the electrolyte.

[0007] Thus, a battery device is being considered, comprising: - electrodes comprising an anode and a cathode, and - an electrolyte, between the electrodes, comprising a crystalline material of composition M2B2O5.x(HOH).y(NOH), where M and N are alkali metals or hydrogen, or mixtures of alkali metals or hydrogen, B is titanium, O and H denote the elements oxygen and hydrogen respectively, and x and y are between 0 and 4 and indicate the presence of H+ ions + , OH-, N +, capable of migrating in the crystalline material, a device in which at least one of the ions among H + OFT, N + and M + is mobile to migrate within the crystalline material towards at least one of the electrodes, and said at least one of the electrodes is made of a material capable of undergoing a chemical interaction with at least one of said H ions + , OH-, N + and M + .

[0008] The term "chemical interaction" as used above refers to the intercalation of an ion migrating towards the electrode, or a chemical reaction between this ion and the electrode material. Thus, the aforementioned chemical interaction includes one of the following: - an intercalation of at least one of the H ions + , OH-, N + and M + in said at least one of the electrodes, and - a chemical reaction (typically electrochemical) involving at least one of the H+ ions + , OH-, N +and M + with the material of said at least one of the electrodes.

[0009] In the device described in the aforementioned document WO-2018 / 060656, migrating ionic species accumulated near the electrodes, generating a charge buildup that enabled the collection, storage, and release of electrical energy, albeit in a purely electrostatic form. Therefore, the amount of energy stored in the device constructed according to the teachings of document WO-2018 / 060656 remained limited by the electrostatic nature of the storage.

[0010] Here, the chemical interaction with the electrode allows for more efficient control of the charge / discharge, and increases the energy storage density.

[0011] The prior art cited above did not provide for electrodes to be composed of materials specifically designed to intercalate ions or to undergo electrochemical reactions with migrating ionic species. Thus, the migrating species in the electrolyte (namely, in particular OH-, H2) were not taken into account. + , O 2 ) can react chemically with the materials that make up the electrodes or become intercalated within them.

[0012] This implementation provides the battery device, as described herein, with the microscopic faradaic mechanisms typically found in battery, cell, or fuel cell devices, enabling precise control of charging and discharging. Specifically, the energy density is improved by adding intercalation, ion absorption, or electrochemical reaction mechanisms to the surface of the electrodes used, as well as by expanding the range of migrating species in the electrolyte. The electrode materials were then selected to match the migrating species in the electrolyte, thus enabling the fabrication of a rechargeable battery, cell, or fuel cell device.

[0013] The solid electrolyte can be in the form of single crystals, ceramics, pressed powders, membranes, or thin films. Its general formula is M2Ti2O5.x(H2O) or M2Ti2O5.x(NOH), where M is one or more alkali metals (and / or hydrogen); N is one or more alkali metals (and / or hydrogen); and x can be equal to 0. This electrolyte material is denoted "MTO" below for brevity.

[0014] Electrode materials can be in solid, liquid, or gaseous form, as explained below.

[0015] In a typical embodiment, the battery device may include an anode made of a material containing a metal hydride, for a chemical reaction with migrating ions of the OH- type.

[0016] Alternatively, the anode can be made of a material containing at least one element from Zinc, Iron and Aluminium (or even sodium or lithium), for a chemical reaction with migrating OH- type ions.

[0017] Alternatively, the anode can be made from a material containing dihydrogen, for a chemical reaction with migrating ions of the OH- type.

[0018] As for the cathode, it can contain a mixture of oxygen and water.

[0019] For example, the cathode can be made of a material containing Nickel oxohydroxide (NiOOH).

[0020] Alternatively, the cathode may contain silver oxide (AgO).

[0021] In such an embodiment, the cathode can initially be made of a material containing silver (Ag), and silver oxide (AgO) can then form at an interface with the electrolyte, typically when the cathode is left in ambient air (in particular to provide the aforementioned mixture of oxygen and water), in accordance with the embodiment described later with reference to Figure 6.

[0022] In one particular embodiment, the device can exploit migrating H+ ions + and OH- in the electrolyte, and include: - a cathode made of a material containing silver and intercalating OH- ions, and - an anode made of a material with an M2B3O7 type structure where M is an alkali element or mixtures of alkali elements, B is titanium, and O is oxygen, to intercalate the H ions + .

[0023] Alternatively, the device may include: - a cathode made of a material containing silver and intercalating OH- ions, and - an anode made of a material containing graphite and intercalating H+ ions + .

[0024] Alternatively, in a battery device where x=0 and M and / or N include at least one element from among sodium and lithium, the device may include: - an anode made of a material containing one of the following elements: sodium and lithium (for example, in metallic form), and - a cathode allowing the incorporation of sodium and / or lithium ions.

[0025] For example, such a cathode can be made of a material such as graphite and a structure of the type M2B3O7, where M' is an alkali element or mixtures of alkali elements, B is titanium, and O is oxygen, to intercalate the migrating M ions + and / or N + .

[0026] In one or more embodiments presented above, the anode material and the electrolyte material can be deposited successively as thin films. respective (this implementation being typically easy to implement when the anode is made of an M2B3O7 structural material).

[0027] In one or more of the embodiments presented above, at least the anode is encapsulated in a resin-type material or equivalent to be airtight and moisture-proof.

[0028] In addition, the entire device (anode, electrolyte and cathode) can be encapsulated in a resin-type material or equivalent to be airtight and moisture-proof.

[0029] When the electrode materials are in solid form or when one of the electrodes is simply made of ambient air (for example the cathode in some embodiments presented above), it is then possible to make a so-called "all-solid" battery.

[0030] More generally, the choice of materials for the anode and cathode can be made as follows: the value of the standard redox potential of the couple involved at the anode (E0a) must be lower than the value of the standard redox potential of the couple involved at the cathode (E0c). Depending on the choice of electrodes, it is then possible to classify the designs by the nature of the migrating species within the electrolyte.

[0031] In an embodiment exploiting the migration of OH- ions, the electrolyte material will create highly mobile OH- hydroxide ions by spontaneous hydration.

[0032] In this case, for example when manufacturing a rechargeable battery, it may be advantageous to choose: - a metal hydride (such as MgH2 for example) as an anode material, and - Nickel oxohydroxide (NiOOH) as the cathode material.

[0033] To make another type of battery: - a metal such as Zinc (or Iron or Aluminum, or a mixture) can be used at the anode, and - Silver oxide (AgO), or even an O2 - H2O mixture, can be used as a cathode material.

[0034] To build a fuel cell: - Dihydrogen can be used as an anode material, and - a mixture of O2 and H2O can be used as a cathode material.

[0035] Furthermore, the generation of a mixed migration of both hydroxide ions OH' and hydrogen ions H + is possible and can be advantageously exploited.

[0036] Indeed, by including oxygen vacancies in the structure of the electrolyte material, it is possible to cause the dissociation of water vapor into H₂ + and OH-. These two species can then migrate independently of each other, so that the following electrode choices are possible.

[0037] A silver cathode, for example (Ag), can react electrochemically with OH- ions, typically. At the anode, intercalation or electrochemical reaction with H+ ions occurs. + maybe ensured by graphite-based compounds, or by a solid material similar to that of the electrolyte, such as A2Ti3U7, where A can be an element such as sodium Na, potassium K, or rubidium Rb, or any type of material capable of intercalating H + .

[0038] This design has the advantage of growing on a suitable substrate a first electrode (anode) of type fcTiaO? for example, having the property of intercalating protons, then the solid electrolyte afterwards, for example K2I2O5, easy to grow on the anode given the proximity of the crystalline phases (and lattice agreement for example), and finally a layer of Ag or graphite which does not pose any problem of deposition or interface on the solid electrolyte, to form the cathode.

[0039] This achievement solves a problem frequently encountered in the field of all-solid-state batteries, which is the quality of the electrode / electrolyte interface when the two materials have crystallographic structures that are too different.

[0040] The migration of other species present in the electrolyte, such as Na + , can be exploited.

[0041] Adding sodium to the chemical formula of MTO yields, for example, the material A2B2O5(NaOH) or A2-xNa x B2O5 which have Na+ ions in their structure + with high mobility.

[0042] Thus, for a rechargeable battery: - the anode material may contain metallic sodium, and - The cathode material may comprise a graphite-based compound, or A2Ti3U7 with A being [Na, K, Rb], or other types of materials that may intercalate Na +

[0043] Depending on the migrating ion species, other applications are of course possible. For example, for exploiting the migration of lithium ions (Li₂O₇²⁻). + By adding lithium to the chemical formula of the electrolyte material, one can obtain the material A2B2O5(LiOH) or A2-xLixB2O5, each possessing Li ions + with high mobility in its structure.

[0044] For a rechargeable battery, the same approach is possible: - as anode material, metallic lithium, and - as a cathode material, a graphite-based compound, or A2Ti3U7 with A being [Na, K, Rb] or other types of materials that can intercalate Li + . Brief description of the drawings

[0045] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1

[0046] [Fig. 1] shows the crystallographic structure of an MTO electrolyte material according to one embodiment. Fig. 2

[0047] [Fig. 2] shows the incorporation of a water molecule into such a material. Fig. 3

[0048] [Fig. 3] shows the thermodynamic energy gain as a function of a percentage of hydration of the sites of the material structure, which shows that the more water molecules there are, the more stable they are. Fig. 4

[0049] [Fig. 4] shows a comparison between electrode arrangements in a "parallel" mode of the material (left figure) or in a "transverse" mode (right figure). Fig. 5

[0050] [Fig. 5] shows a battery-type device, the electrolyte of which is based on the aforementioned MTO material, according to one embodiment. Fig. 6

[0051] [Fig. 6] shows an embodiment of such a device in which the electrodes are based on zinc and silver (oxidizing at the interface with the electrolyte). Fig. 7

[0052] [Fig. 7] shows a prior art device within the meaning of document WO-2018 / 060656, comprising identical electrodes, gold in the embodiment example. Fig. 8

[0053] [Fig. 8] shows a comparison of the electrical performance of the devices in Figures 6 and 7. Description of the implementation methods

[0054] The use of materials from the M2Ti2O5 family (or "MTO" hereafter) with M = [Li, Na, K, Rb, H...] or a combination of these elements (with a structure similar to that described in document WO-2018 / 060656, and particularly Rb2Ti2O5 and K2Ti2O5) as a solid electrolyte for all-solid-state energy storage devices is described below. More generally, the compound family with the formula M2Ti2O5 + i, where x is greater than or equal to 2 and M = [Li, Na, K, Rb], is considered here to offer such properties.

[0055] On a microscopic level, the MTO material is characterized by a lamellar structure with ionic bonds between the Ti2O5 planes 2- and Rb2 2+ The material is lamellar and cleavable along the planes located between the Rb atoms.

[0056] The unhydrated or weakly hydrated material is likely to conduct ionic species such as H+, K+, Rb+, Na+, Li+ depending on the chemical formula of the compound which may combine several cations in its composition such as (Na,K)2Ti2O5.

[0057] In addition to this, there are the possibilities offered by the hydrated MTO material, which is indeed a very hygroscopic material, especially in its powdered form, and possesses the property to spontaneously adsorb water vapor. Ab initio simulations using the density functional method have shown that this molecular water preferentially organizes itself into channels along the crystallographic direction corresponding to the b-axis. The water incorporates itself into the structure by creating hydrogen bonds with the apical oxygens of the perovskite structure as shown in Figures 1 and 2, corresponding to the most probable configuration according to the simulations.

[0058] Adding a water molecule to this configuration thus represents an energy change at T=0 of -0.5 EV (PBEsol method) or -0.25 (HSE method).

[0059] Figure 1 illustrates the insertion of a water molecule, forming very strong hydrogen bonds, within the molecular structure of the material. This structure contains Rb atoms (one atom shown in the upper right of Figure 1), oxygen atoms (one atom shown in the center of Figure 1), hydrogen atoms (two of which are shown to the right of the central oxygen atom in Figure 1), and titanium atoms (Ti) (lower right of Figure 1). This structure, with the general formula MTO, is referred to here more specifically as "RTO," the M atom in the general formula being an Rb atom. Figure 1 thus illustrates the incorporation of a water molecule into the RTO (or more generally MTO) structure, creating two very short hydrogen bonds with the apical oxygen atoms of the structure.Furthermore, simulations show that the energy gained by adding a water molecule to the structure increases with the number of water molecules in the same chain, as illustrated in Figures 2 and 3 discussed later, which favors the creation of chains of water molecules that can give rise in particular to a Grotthus-type proton conduction mechanism in water.

[0060] More generally, the migrating entities within the intercalated water can be one of the following species: OH- and / or M+ with M = [H, Li, Na, K, Rb] and / or O 2- .

[0061] The hydrophilic nature of MTO promotes water absorption.

[0062] As illustrated in Figure 2 for the MTO material with M=Rb, the water molecules arrange themselves in the MO planes (01 designating the apical oxygens of the structure). The molecules organize themselves into chains in the ab planes (forming channels), preferentially oriented with the ab planes parallel to the deposition substrate (the so-called "parallel" orientation), or with the ac planes parallel to the plane of the substrate (the so-called "transverse" orientation), as illustrated respectively on the left and right of Figure 4, in which the lines represent the ab planes of the lamellar compound.

[0063] Typically, Figure 3 shows the thermodynamic energy gain at temperature T=0 as a function of the percentage of hydration of the sites of the structure.

[0064] The MTO materials mentioned above can then be used as a solid electrolyte (and therefore ionically conductive), for example in micrometric or nanometric, planar and crystalline fabrications where the electrolyte consists of a thin layer of MTO deposited on a substrate S such as an integrated circuit by deposition technologies such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition), including, for example, sputtering, pulsed laser ablation, atomic layer deposition, molecular beam epitaxy, deposition by Reactive plasma, or others. The MTO layer is preferentially monocrystalline and / or microcrystalline in regions.

[0065] The electrolyte can alternatively consist of thin layers of MTO obtained by exfoliating sheets from a millimeter-sized crystal. This nanometer-thick sheet (up to a few hundred nm) can then be transferred onto an integrated circuit where it naturally adopts a parallel orientation.

[0066] With reference to Figure 5, in both cases, electrodes A and B are deposited (using vacuum deposition techniques) either on each side of the MTO thin layer in the case of the parallel orientation, or above and below the layer in the case of the transverse orientation, so that ionic conduction occurs preferentially in the crystallographic plane ab (double arrow in Figure 5).

[0067] A controlled hydration step of the thin film can be implemented before or after electrode deposition and before any encapsulation step. Finally, an encapsulant (e.g., silicone, epoxy resin, or a tropicalizing agent, a polyurethane compound, or others) can be deposited over the entire assembly to "lock in" a chosen hydration level of the device.

[0068] Alternatively, the electrolyte can consist of bulk MTO in crystalline form and can thus be composed of one or more oriented single crystals (stacked perpendicular to the crystallographic planes ab) aggregated together in a polymer matrix (epoxy resin, silicone, or polyurethane compound). A controlled hydration step of the crystals can be implemented before encapsulation in the matrix.

[0069] Two electrodes A and B are deposited on each side of the encapsulated single crystals, such that ionic conduction takes place in the crystallographic plane ab, as illustrated by the double arrow in Figure 5.

[0070] Alternatively, the creation of a bulk device can utilize MTO embedded in an encapsulant, with the MTO material then taking a crystalline form in membranes, ceramics, or other materials. For example, the electrolyte can consist of MTO crystals mixed with at least one organic or aqueous solvent (e.g., methyl-2-pyrrolidinone, water, ethanol, or others). A fluorinated compound dispersed in the solvent (e.g., polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or others) can also be added to increase the mechanical stability of the fabrication. The size of the MTO crystals can range from several millimeters to a few hundred nanometers. The volume percentage of MTO can range from 60% to 98%, depending on the solvent chosen. A controlled hydration step can be considered before mixing the powder with the solvent.Depending on the solvent chosen for the fabrication of the device, the duration of the mixing process can extend over several tens of hours and include annealing steps that can reach up to 150°C. Depending on the purpose of the fabrication, the mixture can then be deposited on a non-adhesive substrate (such as a Teflon film) or on an electron-collecting electrode, which can typically interact with ions (for example, Zinc, Gold, Silicon, Sodium, and / or Lithium, metallic ions, or even silver oxide AgO, or others), as detailed below.

[0071] For this purpose, deposition methods can include, for example, inkjet injection, spin-coat deposition, and Dr. Blade deposition. A drying stage can then take several tens of hours at a temperature of up to 150°C. After solvent evaporation, a film with a thickness ranging from a few micrometers to several millimeters is obtained. Subsequently, if the film has been deposited on one electrode, then the other electrode can be placed on top of the film. If the film has been deposited on a non-adhesive substrate, then two electrodes are placed on either side of the film. The film can then be encapsulated with its electrodes, the encapsulation providing good mechanical strength, as well as airtightness and moisture resistance.

[0072] In one embodiment, the electrolyte consists of an MTO ceramic compacted at 10 tons for 2 hours at 150°C and sintered at 800°C for 10 hours. Alternatively, a mass fraction of 2 to 5% PTFE (polytetrafluoroethylene) can be added to the MTO powder to make the ceramic stronger without the sintering step. The electrodes are then deposited with a polymer-solvent-material mixture (8% PVDF: polyvinylidene; 84% solvent: 1-methyl-2-pyrrolidinone; 8% material) and dried for several hours at a temperature between 25 and 80°C. It is also possible to place the powders composing electrodes A and B in the press system to produce the electrodes simultaneously with the ceramic.

[0073] The choice of electrodes for the different geometries of energy storage devices described above must be made according to the migrating species in the electrolyte and the type of device chosen. In the setups considered, MTO material is used as a solid electrolyte placed between an anode made of a material with a standard redox couple E0 a and a cathode made of a material having a standard redox couple E0 c , with E0 a <E0 c .

[0074] Various examples for making the anode and cathode are presented below. An asymmetry can be created between the cathode and the anode by encapsulating one of the electrodes and leaving the other electrode "exposed to the air", which creates the possibility of supplying oxygen or water vapor to the device from only one side and which leads to supercapacitance effects.

[0075] The conduction of OH- ions can be exploited in a metal-air battery-type (non-rechargeable) setup. Materials that can be used as anodes include metallic zinc (Zn), metallic iron (Fe), metallic aluminum (Al), or a metallic alloy composed of at least two of the materials mentioned above.

[0076] An example of a redox reaction occurring at the anode is:

[0078] Examples of materials that can be used as cathodes include: - silver oxide: AgO, or - a mixture of N2 / O2 / H2O gases: ambient air can typically be used (with a humidity level above 5% and below 95%, an oxygen (O2) level above 15% and below 25%, a nitrogen (N2) content greater than 75% and less than 85%), so examples of redox reactions occurring at the cathode might be:

[0080] AgO + H2O + 2 e- → Ag + 2 OH'

[0081] Other designs may utilize a NiMH (Nickel-Metal Hydride) battery assembly. Materials that can be used as anodes include, for example: - alloys of type AB_5, for example based on rare earth (La, Ce, Nd, Pr), such as LaNi5 and derivatives, or alloys including elements among Ni, Co, Mn, Al, Mg, Zr, C, Co, Fe, Ti.

[0082] An example of a redox reaction occurring at the anode could then be: H2O + M + e~, where M is a metallic element originally present as a metal hydride MH (such as TiH2 or MgH2).

[0084] Examples of materials that can be used as cathodes include: - Nickel oxohydroxide (NiOOH), or - a mixture of metal oxide (Ni-Co-Mg), or - a Ni-Co-Al alloy.

[0085] An example of a redox reaction occurring at the cathode might be:

[0087] For the exploitation of proton conduction, materials that can be used as an anode (negative electrode) can include, for example: - WO3, MoOs, TiO2, H2Ti3O?, H2TieOi3, H2Tii2O25 and other derivatives by substitution.

[0088] Examples of materials that can be used as a cathode (positive electrode) include: - a metallic oxide: RuO2, MnO2, V2O5, PbU2 - a protonated metal oxide: HCOO2 - materials with a structure analogous to Prussian blue ("Prussian Blue Analog materials" or "PBA"), for example AxM[Fe(CN)e]y.zH2O - or even organic materials, for example PEDOT or HATN.

[0089] For the exploitation of Li ion conduction +Examples of materials that can be used as anodes (negative electrodes) include: - derivatives of graphite carbon: carbon nanotubes, graphene, mesoporous carbon, etc. - metallic lithium (Li).

[0090] Examples of materials that can be used to form the cathode (positive electrode) include: - lithia-containing metal oxides, for example LiCoO2 - lithium intercalation compounds (e.g., a metal oxide mixture (Ni-Co-Mg), a Ni-Co-Al alloy, Prussian Blue PBA structural materials, etc.).

[0091] For the exploitation of Na ion conduction + Examples of materials that can be used to form the anode (negative electrode) include: - carbon derivatives (graphite, carbon nanotubes, graphene, mesoporous carbon, etc.), - metallic sodium (Na), - sodium alloys: Sodium-Tin (Na-Sn), Sodium-Lead (Na-Pb), Sodium-Bismuth (Na-Bi), - alloys of sodium and intercalated transition metals: Na-Mn-O, Na-Cr-S, Na-Ti-S, - Tin-based compounds: SnO2, SnSb, - layered titanium oxides of the form Na2Ti3O?, Na4Ti50i2, NaTi2(PO4)3 from the electrolyte material family and depositable as a solid thin film, - sodium or vanadium oxide: NaV2O5

[0092] Examples of materials that can be used at the cathode (positive electrode) include: - structural materials such as Prussian blue PBA, - TiSe2 - Na, Fe or Ni phosphate: NaFePC, NaNiPO4 - Sodium oxide, manganese: NaMnO2 - Sodium, nickel, manganese oxide: Na(NiMn)O2 - Sodium oxide, Cobalt or Chromium: NaCoO2, NaCrO2 - Sodium oxide, nickel, Cobalt: Na(NiCo)O2 - Sodium oxide, copper: NaCuO2. Comparative examples

[0093] Figure 6 illustrates an example of the implementation of a device as defined in this description, of which: - the electrolyte comprises the MTO material obtained by implementing the above process from a single crystal or polycrystals compacted in a solvent and then dried between two electrodes, - the anode is made of a zinc-containing material (Zn) and encapsulated in a resin (E) to prevent oxidation, and - the cathode is made of a material containing silver Ag initially, but without being encapsulated, so that the silver oxidizes spontaneously in the open air and in contact with the MTO, so that the material of the cathode is actually silver oxide AgO, and the rest of the initial material Ag serves to efficiently conduct the charges to the cathode wire Fc (made for example of silver, like the anode wire Fa).

[0094] A device in the sense of the prior art (Figure 7) was produced under strictly the same conditions, of which: - the electrolyte comprises the MTO material obtained under the same conditions (from a single crystal or polycrystals compacted in a solvent and then dried, between two electrodes), - the anode and cathode are made of the same material containing gold (excellent conductor but blocking to ions), the anode being encapsulated in a resin E to be in the same experimental conditions as in the device of figure 6, the anode and cathode wires being made of silver, as before.

[0095] Thus, this embodiment, as shown in Figure 6, exploits the migration of OH- ions reacting chemically with the Zn anode according to an equation of the type:

[0097] At the AgO cathode, the ambient air naturally contains water vapor (H2O) and oxygen (O2), so the chemical equations are of the type:

[0099] AgO + H2O + 2 e- → Ag + 2 OH-

[0100] Figure 8 illustrates a comparison of the results and cyclovoltametric curves of the devices in Figures 6 and 7.

[0101] The device in Figure 6 represents a significant improvement over the prior art device (Figure 7). In Figure 8, redox peaks (dashed line) demonstrate the presence of electrochemical reactions that control the charging and discharging of the device. Capacitance is improved by a factor of 10, and energy density by a factor of 20. Furthermore, the observed reversibility in the device's electrical discharge / charge makes it a promising candidate for the fabrication of rechargeable batteries.

[0102] The performance of a device as described herein may be further enhanced with very thin layers of electrodes and electrolyte that can be stacked, allowing for greater densification and improved device performance per unit area.

Claims

Claims

1. Battery device, comprising: - electrodes comprising an anode and a cathode, and - an electrolyte, between the electrodes, comprising a crystalline material of composition M2B2O5.x(HOH).y(NOH), where M and N are alkali or hydrogen elements or mixtures of alkali or hydrogen elements, B is titanium, O and H denote respectively the elements oxygen and hydrogen, and x and y are between 0 and 4 and denote a presence of H ions + , OH-, N + , capable of migrating in the crystalline material, device in which at least one of the ions among H + , OH-, N + and M + is mobile to migrate in the crystalline material towards at least one of the electrodes, and said at least one of the electrodes is made of a material capable of operating a chemical interaction with at least one of said H ions + , OH-, N + and M + .

2. Device according to claim 1, comprising an anode made of a material comprising a metal hydride, for a chemical reaction with migrating ions of OH- type. [Claim s] Device according to claim 1, comprising an anode made of a material comprising at least one element among Zinc, Iron and Aluminum, for a chemical reaction with migrating ions of OH- type.

4. Device according to claim 1, comprising an anode made of a material comprising dihydrogen, for a chemical reaction with migrating ions of the OH- type.

5. Device according to one of the preceding claims, in which the cathode comprises a mixture of oxygen and water.

6. Device according to one of the preceding claims, in which the cathode is made of a material comprising nickel oxohydroxide (NiOOH).

7. Device according to one of claims 1 to 5, in which the cathode comprises silver oxide (AgO).

8. A device according to claim 7, wherein the cathode is made of a material comprising silver (Ag), and wherein silver oxide (AgO) forms at an interface with the electrolyte.

9. Device according to one of claims 5 to 8, in which the cathode is left in the ambient air.

10. A device according to claim 1, wherein the migrating ions in the electrolyte are H + and OH-, the device comprising: - a cathode made of a material containing silver and intercalating the OH- ions, and - an anode made of a material having a structure of type M2B3O7 where M is an element alkali or mixtures of alkali elements, B from titanium, and O from the element oxygen, to intercalate the H ions + .

11. A device according to claim 1, wherein the migrating ions in the electrolyte are H + and OH-, the device comprising: - a cathode made of a material containing silver and intercalating the OH- ions, and - an anode made of a material containing graphite and intercalating the H ions + .

12. Device according to claim 1, in which x=0 and M and / or N comprise at least one element from sodium and lithium, the device comprising: - an anode made of a material comprising one element from sodium and lithium respectively, and - a cathode allowing the incorporation of sodium and / or lithium ions.

13. Device according to claim 12, in which the cathode is made of a material among graphite and a structure of type M 2B3O7 where M' is an alkali element or mixtures of alkali elements, B titanium, and O the oxygen element, to intercalate the migrating ions M + and / or N + .

14. Device according to one of the preceding claims, in which the anode material and the electrolyte material are deposited successively in the form of respective thin layers.

15. Device according to one of the preceding claims, in which the at least one anode is encapsulated in a resin-type material to be airtight and moisture-proof.

16. A device according to any preceding claim, wherein the entire device is encapsulated in a resin-like material to be airtight and moisture-proof.

Images