DE102011079379A1 - Active material, useful for an electrode of a galvanic element, preferably battery for supplying power to the medical implant, which is used for cardiac therapy, comprises metal compounds - Google Patents

Abstract

Active material comprises metal compounds (I). Active material comprises metal compounds of formula (M1 xCu n - x / 2P 2O 5 + n) (I). M1 : monovalent metal e.g. silver; and x, n : greater than 1 to 6, where n is greater than x. Independent claims are included for: (1) the metal compounds (I); (2) producing the active material comprising providing a mixture comprising the starting materials of copper oxide (CuO), a thermally decomposable salt containing phosphate ions comprising diammonium hydrogenphosphate, and a silver compound in a stoichiometry that is appropriate for the desired composition, homogenizing the mixture, providing a single-step or multi-step thermal treatment of the mixture, where the number, the particular duration, and the particular temperature of the steps of the thermal treatment are selected such that the material is formed, and optionally homogenizing the thermally treated mixture; (3) a mixture comprising the active material and one or more conductive additives and/or binding agents, and optionally one or more dispersing agents; and (4) a galvanic element, preferably battery for supplying power to a medical implant with electronic components, comprising an electrode comprising the mixture, the active material or (I).

Description

The present invention relates to a material, in particular an active material for an electrode of a galvanic element, a method for producing this material, a mixture for producing an electrode for a galvanic element and a galvanic element, in particular a battery, and a medical implant comprising such Battery. Another aspect of the present invention relates to a chemical compound of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) and the preparation and use of such chemical compounds.

For powering a medical implant with electronic components, e.g. a pacemaker, with a wireless, preferably bi-directional remote data transmission, galvanic elements, e.g. Batteries required, on the one hand have a high capacity and on the other hand allow the removal of a high discharge current (in mA range). High capacity prolongs the life of the medical implant, reducing the number of surgical procedures needed to replace the battery or implant. An at least short-term removal of a high discharge current (current pulse) is necessary for remote data transmission.

Human medical implants for cardiac therapy are programmed during the implantation process. The programming is conventionally carried out by a programming head, which must be positioned immediately above the implant. Since this programming head can not be sterilized for use in the OR, it must be embedded in a sterile sheath. In order to avoid the expense for the sterile introduction of a programming head into the OR, in a new generation of medical implants for cardiac therapy, the programming of the implant is to take place via radio signals. For this wireless programming, a particularly high power density of the battery of the implant at the beginning of the discharge is required. In order to achieve these high power densities, the voltage of the battery used for the power supply must be as high as possible and its internal resistance as low as possible.

Galvanic elements, e.g. Batteries are electrochemical energy storage and energy converters. The basic components of a galvanic element are a first electrode comprising or consisting of a first active material, a second electrode comprising or consisting of a second active material and an electrolyte connecting the two electrodes. Upon discharge, the stored chemical energy is generated by an electrochemical redox reaction comprising the oxidation of a first active material to release electrons at a first electrode (anode, negative electrode relative to the discharge process) and reduction of a second active material to receive electrons at a second electrode Electrode (cathode, positive electrode with respect to the discharge process) is converted into electrical energy, so that the galvanic element current can be removed.

The capacitance (amount of current that can be removed), the voltage, the internal resistance and other parameters of galvanic elements are significantly influenced by the composition of the active materials used in the electrodes. Active materials are understood to be exclusively those constituents of the electrodes of the galvanic element which oxidize (at the anode) or are reduced (at the cathode) during discharge of the galvanic element and supply electric current through these electrode reactions. In this case, the active material of the cathode may comprise one or more reducible substances and / or the active material of the anode may comprise one or more oxidizable substances.

In addition to the above-defined active materials, the electrodes of galvanic elements usually contain other constituents which do not participate in the current-supplying electrode reactions and therefore do not contribute to the capacitance of the galvanic element, but are required for the reliable operation of the galvanic element, e.g. electronically conductive additives for increasing the electronic conductivity within the electrode, and / or binders for increasing the strength of the electrode.

From the pamphlets DE 10 2006 021 158 A1 . DE 10 2005 059 375 A1 . EP 2 017 910 and US 4,260,668 For example, a battery having a positive electrode containing copper oxyphosphate as an active material is known. The publication US 4,448,864 discloses a lithium manganese dioxide battery whose positive electrode contains manganese dioxide as well as copper oxyphosphate. Such batteries are suitable, inter alia, for the power supply of medical implants. Due to the development tendencies described above, especially in medical implants for cardiac therapy, however, it is necessary to increase the voltage of such galvanic elements, in particular in the initial stage of the discharge process, and the load capacity on discharge by current pulses.

• – Me ist ein einwertiges Metall, z.B. Silber
• – 1 < x ≤ 6
• – 1 < n ≤ 6
• – n > x

This object is achieved by a material, in particular an active material for an electrode of a galvanic element, wherein the material according to the invention comprises or consists of one or more compounds of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) for formula (I):

• - Me is a monovalent metal, eg silver
• - 1 <x ≤ 6
• - 1 <n ≤ 6
• - n> x

In the one or more compounds of the composition (I), the monovalent metal Me is preferably silver.

In the compound or compounds of the composition (I), x is preferably equal to 2.

In the compound or compounds of the composition (I), n is preferably equal to 3 or 4.

A particularly preferred material according to the invention comprises a compound (I) having the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a compound (I) having the composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib).

In addition to one or more compounds of composition (I) as defined above, an active material for an electrode of a galvanic element according to the invention may comprise one or more further chemical compounds which are electrochemically reduced during the discharge process, e.g. Manganese dioxide.

• – eine oder mehrere Verbindungen der Zusammensetzung Cu_mP₂O_5+m (II) wobei für die Formel (II) gilt: 1 < m ≤ 6
• – sowie optional eine oder mehrere weitere Substanzen, die beim Entladevorgang elektrochemisch reduziert werden, wie z.B. Mangandioxid.

In its preferred embodiments, the active material according to the invention contains, in addition to one or more compounds of the above-defined composition (I)

• - One or more compounds of composition Cu _m P ₂ O _{5 + m} (II) wherein for the formula (II): 1 <m ≤ 6
• - And optionally one or more other substances that are electrochemically reduced during the discharge process, such as manganese dioxide.

In a preferred embodiment, the material according to the invention consists of one or more compounds of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) as defined above and one or more compounds of the composition Cu _m P ₂ O _{5 + m} (II ) as defined above.

Among the compounds of the composition (II), those having a high copper content are preferred because of their high theoretical capacity and high solid density. Particularly preferred is the compound of the composition (II) with m equal to 4, Cu ₄ P ₂ O ₉ (IIa).

The active material according to the invention preferably comprises at least one continuous phase and at least one disperse phase.

In these preferred embodiments, the material according to the invention comprises a continuous phase of the composition Cu _m P ₂ O _{5 + m} (II) as defined above and one or more disperse phases of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) or consists of a continuous phase of the composition Cu _m P ₂ O _{5 + m} (II) as defined above and one or more disperse phases of the composition Me _x Cu _{nx / 2} P ₂ O _5-n (I) as defined above.

In a particularly preferred embodiment, the material according to the invention comprises a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a disperse phase of the composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib) or consists of a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a disperse phase of Composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib).

The composition of the respective phases can be identified by X-ray analysis (XRD).

In the material according to the invention, the proportion of silver in the disperse phase of composition (Ia) or (Ib) is preferably 1 mol% to 10 mol%, preferably 5 mol%, based on the content of copper in the continuous phase of the composition ( IIa).

The above-described preferred materials according to the invention comprising or consisting of a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a disperse phase of the composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib) are obtainable via a solid state synthesis, wherein as starting materials copper oxide CuO, a compound of the selected monovalent metal (preferably an oxide or a thermally decomposable salt, eg AgNO ₃ , Ag ₂ CO ₃ ), and a Phosphate ion-containing thermally decomposable salt, eg diammonium hydrogenphosphate (NH ₄ ) ₂ HPO _{4 are used} in a stoichiometry corresponding to the desired composition.

The materials according to the invention, in particular their preferred embodiments, are suitable for use as active material for an electrode of a galvanic element or as part of a mixture according to the invention for producing an electrode for a galvanic element.

• – Me ist ein einwertiges Metall, z.B. Silber
• – 1 < x ≤ 6
• – 1 < n ≤ 6
• – n > x.

A further aspect of the present invention relates to a chemical compound of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) where the following applies for the formula (I):

• - Me is a monovalent metal, eg silver
• - 1 <x ≤ 6
• - 1 <n ≤ 6
• - n> x.

In the compound of the composition (I), the monovalent metal Me is preferably silver.

In the compound of the composition (I), x is preferably equal to 2.

In the compound of the composition (I), n is preferably equal to 3 or 4.

A particularly preferred compound according to the invention has the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia). Another particularly preferred compound according to the invention has the composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib).

The compounds according to the invention are obtainable by solid-state synthesis, using as educts copper oxide CuO, a compound of the selected monovalent metal (preferably an oxide or a thermally decomposable salt, eg AgNO ₃ , Ag ₂ CO ₃ ), and a phosphate ion-containing thermally decomposable salt, For example, diammonium hydrogen phosphate (NH ₄ ) ₂ HPO _{4 can be used} in a stoichiometry corresponding to the desired composition.

The compounds of the invention Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), in particular their preferred embodiments of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib), are suitable for use as an active material for an electrode of a galvanic element and as a constituent of an active material according to the invention for an electrode of a galvanic element or as part of a mixture according to the invention for producing an electrode of a galvanic element.

• – Bereitstellen einer Mischung umfassend die Edukte – Kupferoxid CuO – ein Phosphat-Ionen enthaltendes thermisch zersetzbares Salz, z.B. Diammoniumhydrogenphosphat (NH₄)₂HPO₄ – eine Silberverbindung (vorzugsweise ein Oxid oder ein thermisch zersetzbares Salz, z.B. AgNO₃, Ag₂CO₃) in einer der gewünschten Zusammensetzung entsprechenden Stöchiometrie
• – Homogenisieren der Mischung,
• – ein- oder mehrstufiges thermisches Behandeln der Mischung, wobei die Anzahl, die jeweilige Dauer und die jeweilige Temperatur der Stufen der thermischen Behandlung so gewählt sind, dass die gewünschte erfindungsgemäße Verbindung der Zusammensetzung Ag₂Cu₂P₂O₈ (Ia) und Ag₂Cu₃P₂O₉ (Ib) bzw. das gewünschte erfindungsgemäße Material aus einer kontinuierlichen Phase der Zusammensetzung Cu₄P₂O₉ (IIa) und einer dispersen Phase der Zusammensetzung Ag₂Cu₂P₂O₈ (Ia) oder Ag₂Cu₃P₂O₉ (Ib) gebildet wird,
• – ggf. Homogenisieren der thermisch behandelten Mischung.

The preferred compounds of the invention described above and the preferred materials of the invention described above are preferably obtainable by the process of solid-state synthesis. A process for producing a compound according to the invention or an active material according to the invention comprises the steps:

• - Providing a mixture comprising the starting materials - copper oxide CuO - a phosphate ion-containing thermally decomposable salt, eg diammonium hydrogenphosphate (NH ₄ ) ₂ HPO ₄ - a silver compound (preferably an oxide or a thermally decomposable salt, eg AgNO ₃ , Ag ₂ CO ₃ ) in a stoichiometry corresponding to the desired composition
• Homogenizing the mixture,
• - One or more stages of thermal treatment of the mixture, wherein the number, the respective duration and the respective temperature of the stages of the thermal treatment are selected so that the desired compound of the invention composition of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib) or the desired material according to the invention from a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) or Ag ₂ Cu ₃ P ₂ O ₉ (Ib) is formed,
• - If necessary, homogenizing the thermally treated mixture.

In principle, the reactants are mixed as homogeneously as possible and then thermally treated at sufficiently high temperatures and over a sufficiently long period of time. During this process, one or more compounds of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) are defined as above, in particular Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or Ag ₂ Cu ₃ P ₂ O ₉ (Ib) produced, depending on the composition of the mixture comprising the starting materials and temperature and duration of the thermal treatment compounds of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) either in each case as a pure phase or as a disperse phase in a continuous phase of the composition Cu _m P ₄ O _{5 + m} (II), in particular Cu ₄ P ₂ O ₉ (IIa) are obtained. If necessary, the resulting reaction mixture is homogenized after the thermal treatment.

The thermal treatment of the homogenized mixture comprising the starting materials in a porcelain, corundum or quartz glass crucible is preferably carried out. Typically, the thermal treatment comprises several, especially three, stages, wherein the temperature of the thermal treatment increases from the first to the last, especially from the first to the third stage, but is kept constant during a treatment stage.

The first stage of the thermal treatment preferably comprises annealing the homogenized mixture comprising the educts at a temperature in the range from 120 to 200 ° C., preferably 160 ° C., over a period of from 20 to 60 hours, preferably 48 hours. Preferably, the second step of the thermal treatment comprises annealing the homogenized mixture comprising the starting materials at a temperature in the range from 250 to 350 ° C, preferably 290 ° C, over a period of 20 to 60 hours, preferably 48 hours. Temperature and duration of the third stage of the thermal treatment depend on the composition of the desired compound of the invention Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) or according to the desired composition and amount of the disperse phase of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) in a material according to the invention.

In order to obtain a material according to the invention which comprises or consists of a disperse phase of the composition Me _x Cu _{nx / 2} P ₂ O _5-n (I) and a continuous phase of the composition Cu _m P ₂ O _5-m (II) the last stage of the thermal treatment is carried out at a temperature in the range of 600 to 800 ° C for a period of 10 to 20 days, the mixture being homogenized every one to every fifth day (preferably every third day).

• – einer ersten Stufe bei 160°C für 48 Stunden
• – einer zweiten Stufe bei 290°C für 48 Stunden
• – einer dritten Stufe bei 750°C für 16 Tage.

For example, the preparation of an active material according to the invention having a silver content of 1 mol% comprises a three-stage thermal treatment with

• A first stage at 160 ° C for 48 hours
• A second stage at 290 ° C for 48 hours
• - a third stage at 750 ° C for 16 days.

• – einer ersten Stufe bei 160°C für 48 Stunden
• – einer zweiten Stufe bei 290°C für 48 Stunden
• – einer dritten Stufe bei 750°C für 13 Tage.

For example, the preparation of an active material according to the invention with a silver content of 5 mol% comprises a three-stage thermal treatment with

• A first stage at 160 ° C for 48 hours
• A second stage at 290 ° C for 48 hours
• - a third stage at 750 ° C for 13 days.

• – einer ersten Stufe bei 160°C für 48 Stunden
• – einer zweiten Stufe bei 290°C für 48 Stunden
• – einer dritten Stufe bei 700°C für 14 Tage.

For example, the preparation of an active material according to the invention having a silver content of 10 mol% comprises a three-stage thermal treatment with

• A first stage at 160 ° C for 48 hours
• A second stage at 290 ° C for 48 hours
• - a third stage at 700 ° C for 14 days.

The composition of the phases formed can be identified by X-ray diffraction (XRD).

In order to obtain a compound of the invention Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), as a pure phase, the last stage of the thermal treatment is carried out at a temperature in the range of 600 to 670 ° C over a period of 5 to 15 days, preferably 12 days, homogenizing the mixture every 1 to 5 days (preferably every 3 days).

• – einer ersten Stufe bei 160°C für 48 Stunden
• – einer zweiten Stufe bei 290°C für 48 Stunden
• – einer dritten Stufe bei 600°C für 5 bis 15 Tage (vorzugsweise 12 Tage).

For example, the preparation of the compound of the invention Ag ₂ Cu ₂ P ₂ O ₈ (Ia) comprises a three-stage thermal treatment with

• A first stage at 160 ° C for 48 hours
• A second stage at 290 ° C for 48 hours
• A third stage at 600 ° C for 5 to 15 days (preferably 12 days).

• – eine erste Stufe bei 160°C für 48 Stunden
• – eine zweite Stufe bei 290°C für 48 Stunden
• – eine dritte Stufe bei 670°C für 5 bis 15 Tage (vorzugsweise 12 Tage).

For example, the preparation of the compound Ag ₂ Cu ₃ P ₂ O ₉ (Ib) according to the invention comprises a three-stage thermal treatment

• A first stage at 160 ° C for 48 hours
• A second stage at 290 ° C for 48 hours
• A third stage at 670 ° C for 5 to 15 days (preferably 12 days).

Preferably, the mixture is homogenized after each stage of the thermal treatment and, if necessary, comminuted. After completion of the thermal treatment, the mixture is homogenized again and optionally comminuted.

The material according to the invention, in particular in its preferred embodiments, is suitable for use as active material for an electrode of a galvanic element, in particular for a (based on the discharge process) positive electrode (cathode) of a galvanic element. During the discharge process, ions of the monovalent metal Me, e.g. Silver reduced to the elemental metal and in the course of the discharge copper ions to metallic copper. Lithium ions are stored in the crystal lattice of the positive electrode active material during discharge.

The inventive method for producing an active material for an electrode of a galvanic element based on a solid state synthesis with a reaction mixture in which the reactants are homogeneously distributed, a material is available which has a high degree of dispersity. In the production of electrodes comprising the active material according to the invention, it is therefore not necessary to take technical measures in order to avoid, during processing, separation of the components of the active material, e.g. by their different density could be caused to avoid. Due to the homogeneous distribution of the components within the active material according to the invention, the discharge of the electrode is homogeneous.

It is assumed that in the preferred active materials according to the invention, owing to the molecular dispersion of the compound Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), in particular Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or Ag ₂ Cu ₃ P ₂ O ₉ (Ib), in which a continuous phase-forming compound of composition Cu _m P ₂ O _5-m (II), in particular Cu ₄ P ₂ O ₉ (IIa), defect structures arise, which in comparison to Structure of the known from the prior art active material Cu _m P ₂ O _{5 + m} (II) facilitate the mobility of ions in the lattice structure of the active material according to the invention. However, the present invention is not bound to this theory.

• (i) ein erfindungsgemäßes Aktivmaterial wie oben beschrieben oder eine oder mehrere erfindungsgemäße Verbindungen der Zusammensetzung Me_xCu_n-x/2 P₂O_5+n (I) wie oben beschrieben, vorzugsweise eine oder beide Verbindungen der Gruppe bestehend aus Ag₂Cu₂P₂O₈ (Ia) und Ag₂Cu₃P₂O₉ (Ib), sowie
• (ii) ein oder mehrere leitfähige Additive und/oder
• (iii) ein oder mehrere Bindemittel sowie
• (iv) optional ein oder mehrere Dispergiermittel oder besteht aus den Komponenten (i), (ii) und/oder (iii) und optional (iv).

Another aspect of the present invention relates to a mixture for producing an electrode for a galvanic element. The mixture according to the invention for producing an electrode for a galvanic element comprises:

• (i) an active material according to the invention as described above or one or more compounds according to the invention of the composition Me _x Cu _{nx / 2P 2} O _{5 + n} (I) as described above, preferably one or both compounds of the group consisting of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib), as well as
• (ii) one or more conductive additives and / or
• (iii) one or more binders as well
• (iv) optionally one or more dispersing agents or consists of components (i), (ii) and / or (iii) and optionally (iv).

The mixture according to the invention can be present, for example, as a solid mixture (without dispersant (iv) or as a dispersion in a typically liquid dispersant (iv).

As conductive additives (ii), electronically conductive materials are used which do not participate in the current-supplying electrode reaction. The function of the conductive additive or conductive additives (ii) is to increase the electronic conductivity within the electrode and to make electronic contact to the arrester (typically a metallic grid or metallic foil incorporated in the electrode) or to connect the electrode improve. This is achieved by a uniform, finely dispersed distribution of a particulate conductivity additive in the active material, so that the particles of the conductive additive (ii) electronically conductive contacts between the particles of the inventive Form active material or the compound of the invention or between particles of the active material according to the invention or the compound of the invention and the arrester or terminal. As a result, the ohmic resistance of the electrode and thus the internal resistance of the galvanic element is reduced overall.

In the mixture of the present invention, the conductive additive or conductive additives are preferably selected from the group consisting of graphite, carbon black, graphite expandate, carbon fibers and metal powders.

In order to achieve a homogeneous, finely dispersed distribution of the conductive additive or of the conductive additives (ii) in the active material or the compound according to the invention and reliable electronic contacting within the electrode, it is preferred to use combinations of conductive additives of different particle size and shape, e.g. Graphite expandate in combination with spherical or platelet-shaped graphite or carbon fibers in combination with spherical or platelet-shaped graphite.

The amount of the conductive additive or additives (ii) should be chosen so that on the one hand an effective reduction of the internal resistance is achieved, but on the other hand, the proportion of the active material according to the invention or the compound according to the invention is not reduced so that the capacity of the galvanic element unacceptably reduced becomes. Preferably, the content of the conductive additive or of the conductive additives (ii) in the total mass of the mixture according to the invention in the range of 0.1 to 20 wt.%, Preferably from 3 to 10 wt.%.

The function of the binder or binders (iii) is to increase the integrity of the constituents of the electrode and thus the mechanical strength of the electrode. Suitable binders are, for example, polymers. In the mixture of the invention, the binder or binders are preferably selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), polyolefins, polyethylene oxide (PEO), polyethylene (PE), polypropylene (PP), polyacrylates and ethylene-propylene Diene monomer (EPDM).

The amount of binder or binders (iii) should be chosen such that on the one hand the required mechanical strength is achieved, but on the other hand the proportion of active material according to the invention or the compound according to the invention is not reduced so much that the capacity of the galvanic element is unacceptably reduced. The content of the binder or of the binder (iii) in the total mass of the mixture according to the invention is preferably in the range from 0 to 12% by weight, preferably from 1 to 8% by weight.

The mixture for producing an electrode for a galvanic element is a dry mixture or a dispersion. To prepare a mixture according to the invention are the o.g. Ingredients (i), (ii) and / or (iii) and optionally (iv) and further additives (e.g., magnesium oxide, lithium carbonate) are provided according to their respective proportions of the total mass of the mixture and mixed homogeneously.

The mixture according to the invention, in particular in its preferred embodiments, is suitable for producing an electrode for a galvanic element according to the invention.

• a) Bereitstellen einer erfindungsgemäßen Mischung (wie oben beschrieben) zur Herstellung einer Elektrode für ein galvanisches Element
• b) Verfestigen der in Schritt a) bereitgestellten Mischung.

The production of an electrode for a galvanic element according to the invention comprises the steps

• a) providing a mixture according to the invention (as described above) for producing an electrode for a galvanic element
• b) solidifying the mixture provided in step a).

In step b), the solidification of the mixture according to the invention provided in step a) can be carried out, for example, by means of uniaxial, biaxial or isostatic pressing. Particularly preferably, the solidification of the mixture provided in step a) or of the active material provided in step a) takes place by means of a stamp-die process. Optionally, a drying step may be followed by step b), eg vacuum drying. Preferably, the vacuum drying is carried out for at least 8 hours at 80 to 340 ° C, preferably at temperatures between 120 ° C and 180 ° C. If the solidified product obtained in step b) does not yet have the desired shape for use as an electrode, the solidified and optionally dried product can be brought into the desired shape by further processing steps, for example cutting. For further details of the preparation of the electrodes, reference is made to the documents DE 10 2006 021 158 A1 . DE 10 2005 059 375 A1 and EP 2 017 910 refer.

As an alternative method for producing the electrodes, coating methods with dispersions are suitable. For this purpose, a mixture according to the invention is prepared by (i) dispersing an active material according to the invention or one or more compounds according to the invention with one or more conductive additives (ii) and / or one or more binders (iii) in a dispersant (iv). The present invention in the form of a dispersion mixture is applied by means of a wet coating process, for example by roller coating, knife coating, printing or casting as a wet film on an electronically conductive support, usually a metal foil, and solidified in this way. The wet film is then dried and optionally compressed, for example by calendering.

• – eine erfindungsgemäße Mischung (wie oben beschrieben) oder
• – ein erfindungsgemäßes Aktivmaterial (wie oben beschrieben) oder
• – eine oder mehrere erfindungsgemäße Verbindungen der Zusammensetzung Me_xCu_n-x/2 P₂O_5+n (I) wie oben beschrieben, vorzugsweise eine oder beide Verbindungen der Gruppe bestehend aus Ag₂Cu₂P₂O₈ (Ia) und Ag₂Cu₃P₂O₉ (Ib),

Another aspect of the present invention relates to a galvanic element, preferably a battery, in particular for powering a medical implant with electronic components. The galvanic element according to the invention comprises an electrode, in particular a (based on the discharge process) positive electrode (cathode) consisting of or comprising

• A mixture according to the invention (as described above) or
• - An inventive active material (as described above) or
• One or more compounds according to the invention of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) as described above, preferably one or both compounds of the group consisting of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib),

Preferably, the active material of the second, (based on the discharge process) negative electrode (anode) contains metallic lithium or consists thereof. Alternatively, alloys of lithium can be used.

In the case of lithium as the active material for the anode of the galvanic element according to the invention, the electrolyte is typically an anhydrous solution of a lithium compound, e.g. a lithium salt, in a nonaqueous organic solvent or in a mixture of nonaqueous organic solvents. The lithium salts used are preferably salts with chemically less or non-reactive anions. Examples thereof are lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium tetrachloroaluminate, lithium tetrafluoroborate or lithium perchlorate.

The solvents used are preferably compounds which have a high solubility for the lithium salt to be used in the electrolyte, do not react chemically or only slightly with the electrode materials and do not bring the electrode material into solution. Examples of typical solvents in electrolytes of lithium batteries are propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, 2-methyltetrahydrofuran, dioxolane, γ-butyrolactone, acetonitrile, digylme, 1,2-dimethoxyethane, dimethylformamide. Preferred solvents are e.g. Dimethoxyethane, ethylene carbonate and propylene carbonate. A particularly preferred electrolyte is a 1 molar solution of lithium perchlorate in a mixture of 1,2-dimethoxyethane, ethylene carbonate and propylene carbonate (4: 4: 2).

The galvanic element according to the invention, in particular in its preferred embodiments, can for example be used to power a medical implant containing electronic components. For example, the medical implant is selected from the group consisting of cardiac pacemakers, defibrillators, sensors for measuring, recording and transmitting physiological data, neurostimulators, orthopedic implants, dosing pumps and implants with metering or valve function.

Preferably, the galvanic element according to the invention forms a battery, which in turn preferably forms part of a medical implant, e.g. a pacemaker or a heart stimulator.

A further aspect of the present invention therefore relates to a medical implant, in particular a medical implant for cardiac therapy, e.g. a pacemaker or a heart stimulator, comprising a galvanic element according to the invention, preferably a battery according to the invention.

The use of a material according to the invention as described above or a compound according to the invention as described above as active material or as constituent of an active material for an electrode, especially the (relative to the discharge process) positive electrode (cathode) of a galvanic element allows various improvements over known from the prior art galvanic elements with copper oxyphosphate as the active material.

During the discharge process, first the ions of the monovalent metal Me are reduced to the elemental metal, eg silver, and in the further course of the discharge the copper ions become metallic copper. The discharge of silver ions occurs at a higher voltage than the discharge of the copper ions. By varying the proportion of the compound or compounds having the composition Me _x Cu _{nx / 2} P ₂ O _5-n (I), in particular Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or Ag ₂ Cu ₃ P ₂ O. ₉ (Ib) in the preferred active materials according to the invention described above, it is possible to set the amount of current (capacitance) which can be taken from a galvanic element at the higher voltage than the discharge of the copper ions. Particularly preferred embodiments of the galvanic element according to the invention have a voltage of approximately 3.4 V at the beginning of the discharge over a resistance of 100 kOhm. The elemental metal, eg silver, formed in the initial stage of the discharge process by reducing the ions of the monovalent metal improves the electronic conductivity Contacting within the electrode, so that their ohmic resistance and thus the internal resistance of the galvanic element is reduced overall. The elemental metal formed upon discharge thus acts similarly to the conductive additives (ii) described above, but has the advantage that it is formed by a reaction which itself contributes to the capacitance of the galvanic element. Moreover, the electrical resistivity of the elemental metal formed upon discharge is lower than the resistivity of the carbonaceous additives commonly employed.

Thanks to the high voltage and the rapid drop of the internal resistance at the beginning of the discharge process of a galvanic element according to the invention, the high power density desired in particular for use in the power supply of medical implants can be realized at the beginning of the discharge process.

It is assumed that in the preferred active materials according to the invention, because of the molecular dispersion of the compound of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), especially Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or Ag ₂ Cu ₃ P ₂ O ₉ (Ib) are formed in the continuous phase forming compound of composition Cu _m P ₂ O _5-m (II), especially Cu ₄ P ₂ O ₉ (IIa) defect structures, which in comparison to the structure of known from the prior art active material Cu _m P ₂ O _5-m (II) facilitate the mobility of ions in the lattice structure of the active material according to the invention. It is thereby achieved that, even after complete discharge of the silver, the voltage during the discharge of the copper ions is higher than in the case of a galvanic element whose cathode as active material Cu _m P ₂ O _{5 + m} (II) without a disperse compound of composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), especially Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or Ag ₂ Cu ₃ P ₂ O ₉ (Ib). However, the present invention is not bound to this theory.

Both in the initial stage of the discharge process (discharge of the ions of the monovalent metal) and in the stage of discharge of the copper ions relatively high voltage and the reduced internal resistance of the galvanic element according to the invention allow high load capacity in pulse discharge. The voltage of a galvanic element according to the invention remains always high enough during a load by current pulses, which are typical for the data telemetry to external transmitters and receivers, so that a full functionality of the electronic components of the implant is ensured. This is particularly important if the implant is to transmit and receive data wirelessly via RF telemetry during the implantation process, ie at the beginning of the discharge of the galvanic element. Therefore, the high initial load capacity of the galvanic element according to the invention by current pulses at the same time high voltage represents another important for use for power supply medical implants technical advantage.

embodiments

Other features, advantages and applications of the present invention will become apparent from the following described embodiments and comparative examples in conjunction with the figures.

The figures show:

1 Cell voltage of various inventive batteries (with a cathode according to the embodiment 1, 2 or 3) and a non-inventive battery (with a cathode according to the comparative example) as a function of the withdrawn amount of current (capacity) when discharged through a load of 100 kOhm.

2 Cell voltage of various inventive batteries (with a cathode according to the embodiment 1, 2 or 3) and a non-inventive battery (with a cathode according to the comparative example) as a function of the withdrawn amount of current (capacity) at pulse discharge (pulse current 2 mA / cm ² , Pulse duration 2 s).

3 Internal resistance of various inventive batteries (with a cathode according to the embodiment 1, 2 or 3) and a non-inventive battery (with a cathode according to the comparative example) depending on the amount of electricity drawn (capacity).

4 Cell voltage of two batteries according to the invention (with a cathode according to the embodiment 4 or 5) and a battery not according to the invention (with a cathode according to the comparative example) as a function of the withdrawn amount of current (capacity) at discharge over a load of 100 kOhm.

5 Cell voltage of two batteries according to the invention (cathode according to the embodiment 4 or 5) and a non-inventive battery (with a cathode according to the comparative example) as a function of the withdrawn amount of current (capacity) at pulse discharge (pulse current 2 mA / cm ² , pulse duration 2s).

6 Internal resistance of two batteries of the invention (with a cathode according to the embodiment 4 or 5) and a non-inventive battery (with a cathode according to the comparative example) as a function of the amount of electricity drawn (capacity).

For the embodiments and comparative examples, galvanic elements were produced in the form of batteries with the following structure: Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Comparative example Active material of the cathode continuous: Cu ₄ P ₂ O ₉ disperse: Ag ₂ Cu ₂ P ₂ O ₈ (1 mol% Ag) continuous: Cu ₄ P ₂ O ₉ disperse: Ag ₂ Cu ₂ P ₂ O ₈ (5 mol% Ag) continuous: Cu ₄ P ₂ O ₉ disperse: Ag ₂ Cu ₂ P ₂ O ₈ (10 mol% Ag) Ag ₂ Cu ₃ P ₂ O ₉ Ag ₂ Cu ₂ P ₂ O ₈ Cu ₄ P ₂ O ₉ Conductive additives of the cathode Graphite (3% by weight) and carbon fibers (2% by weight) Binding means of the cathode Polytetrafluoroethylene (3% by weight) electrolyte 1 molar solution of LiClO ₄ in a mixture of 1,2-dimethoxyethane, ethylene carbonate and propylene carbonate (4: 4: 2). anode lithium

The proportions (in% by weight) of the conductive additives and the binder of the cathodes refer to the total mass of active material, conductive additives and binders of the respective cathode.

In the active materials of the cathodes of Embodiments 1 to 3, a phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) corresponding to the stated percentage of silver is finely dispersed in a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) , The percentage (in mol%) of the respective active material of silver refers to the content of the copper contained in the active material compound (IIa). During the discharge process, the metal ions of both compounds, (Ia) and (IIa), are reduced.

• – Bereitstellen einer Mischung der Edukte Kupferoxid, Diammoniumhydrogenphosphat und Silbernitrat in stöchiometrischen Mengen gemäß der gewünschten Zusammensetzung, wobei die zu ersetzenden Kupfer-Ionen durch die ladungsäquivalente Menge an Silber-Ionen substituiert werden
• – Homogenisieren der Mischung
• – Tempern der homogenisierten Mischung für 48 Stunden bei 160°C in Porzellan-, Korund- oder Quarzglastiegel
• – Homogenisieren und gegebenenfalls Zerkleinern der Mischung
• – Tempern für 48 Stunden bei 290°C
• – Homogenisieren und gegebenenfalls Zerkleinern der Mischung
• – weiteres Tempern bei 600°C bis 800°C für 10 bis 20 Tage zum Erhalt eines Materials der gewünschten Zusammensetzung, insbesondere – für einen Silbergehalt von 1 mol%: 16 Tage bei 750°C (Ausführungsbeispiel 1) – für einen Silbergehalt von 5 mol%: 13 Tage bei 750°C (Ausführungsbeispiel 2) – für einen Silbergehalt von 10 mol%: 14 Tage bei 700°C (Ausführungsbeispiel 3) dabei in allen Fällen Homogenisieren der Mischung an jeden bis jeden fünften Tag (vorzugsweise jeden dritten Tag)
• – nach Abschluss der thermischen Behandlung nochmaliges Homogenisieren und gegebenenfalls Zerkleinern der Mischung.

The active materials of the cathodes of Embodiments 1 to 3 are produced by a method comprising the following steps:

• Providing a mixture of the educts copper oxide, diammonium hydrogen phosphate and silver nitrate in stoichiometric amounts according to the desired composition, wherein the copper ions to be replaced are substituted by the charge-equivalent amount of silver ions
• - Homogenizing the mixture
• - Annealing the homogenized mixture for 48 hours at 160 ° C in porcelain, corundum or quartz glass crucibles
• - Homogenizing and optionally comminuting the mixture
• - annealing for 48 hours at 290 ° C
• - Homogenizing and optionally comminuting the mixture
• - further annealing at 600 ° C to 800 ° C for 10 to 20 days to obtain a material of the desired composition, in particular - for a silver content of 1 mol%: 16 days at 750 ° C (Example 1) - for a silver content of 5 mol%: 13 days at 750 ° C (Embodiment 2) - for a silver content of 10 mol%: 14 days at 700 ° C (Embodiment 3) in all cases homogenizing the mixture every one to every fifth day (preferably every third day )
• - After completion of the thermal treatment, repeated homogenization and optionally comminution of the mixture.

• – Bereitstellen einer Mischung umfassend die Edukte z.B. Kupferoxid, Diammoniumhydrogenphosphat und Silbernitrat in stöchiometrischen Mengen gemäß der Summenformel der gewünschten Phase
• – Homogenisieren der Mischung
• – Tempern der homogenisierten Mischung für 48 Stunden bei 160°C in einem Porzellan-, Korund- oder Quarzglastiegel
• – Homogenisieren und gegebenenfalls Zerkleinern der Mischung
• – Tempern für 48 Stunden bei 290°C
• – Homogenisieren und gegebenenfalls Zerkleinern der Mischung
• – weiteres Tempern zum Erhalt der kontinuierlichen Phase – mit der Zusammensetzung (Ia) bei 600°C für 5 bis 15 Tage (vorzugsweise 12 Tage) bzw. – mit der Zusammensetzung (Ib) bei 670°C für 5 bis 15 Tage (vorzugsweise 12 Tage), dabei in beiden Fällen Homogenisieren der Mischung an jeden bis jeden fünften Tag (vorzugsweise an jeden dritten Tag)
• – nach Abschluss der thermischen Behandlung nochmaliges Homogenisieren und gegebenenfalls Zerkleinern der Mischung.

The pure phase with the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) or Ag ₂ Cu ₃ P ₂ O ₉ (Ib), which forms the active material of the cathode in the cathode of the embodiment 4 and 5, according to a Method comprising the following steps:

• - Providing a mixture comprising the starting materials such as copper oxide, diammonium hydrogen phosphate and silver nitrate in stoichiometric amounts according to the empirical formula of the desired phase
• - Homogenizing the mixture
• - Annealing the homogenized mixture for 48 hours at 160 ° C in a porcelain, corundum or quartz glass crucible
• - Homogenizing and optionally comminuting the mixture
• - annealing for 48 hours at 290 ° C
• - Homogenizing and optionally comminuting the mixture
• - further annealing to obtain the continuous phase - with the composition (Ia) at 600 ° C for 5 to 15 days (preferably 12 days) or - with the composition (Ib) at 670 ° C for 5 to 15 days (preferably 12 In both cases, homogenizing the mixture on each and every fifth day (preferably every third day)
• - After completion of the thermal treatment, repeated homogenization and optionally comminution of the mixture.

• – Trockenes Mischen des Aktivmaterials mit den entsprechenden Mengen der leitfähigen Additive und des Bindemittels zu einer homogenen Mischung
• – Kompaktierung der homogenen Mischung mittels eines Stempel/Matrize-Verfahrens
• – Vakuumtrocknung bei 140–180°C über mindestens 8 Stunden.

The cathodes of Embodiments 1 to 5 and Comparative Example were prepared as follows:

• Dry mixing of the active material with the appropriate amounts of the conductive additives and the binder to form a homogeneous mixture
• - Compaction of the homogeneous mixture by means of a stamp / die process
• - Vacuum drying at 140-180 ° C for at least 8 hours.

The batteries of Embodiments 1 to 5 and Comparative Example 1 were examined with respect to their discharge characteristics in the base load mode with a load of 100 kOhm and pulse mode (pulse current 2 mA / cm ² , pulse duration 2 s). In addition, the change in the internal resistance with the amount of electricity taken (capacity) was followed. The results of these investigations are in the 1 to 6 shown.

In the 1 and 4 It can be seen that the batteries according to the invention of the embodiments 1 to 5 both at the beginning and in the further course of the discharge process have a higher cell voltage than the non-inventive battery of the comparative example. This also applies to the discharge during pulse loading, see 2 and 5. The higher the proportion of the active material of the cathode of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) or Ag ₂ Cu ₃ P ₂ O ₉ (Ib), the greater the capacitance range in which the voltage is not despite pulse loading below 2.6 V decreases.

The 3 and 6 show that the internal resistance of the batteries according to the invention at the beginning of the discharge due to the formed metallic silver drops much faster than in Comparative Example 1.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006021158 A1 [0007, 0058]
• DE 102005059375 A1 [0007, 0058]
• EP 2017910 [0007, 0058]
• US 4260668 [0007]
• US 4448864 [0007]

Claims (14)

Material, in particular active material for an electrode of a galvanic element, comprising - or consisting of one or more compounds of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I), - where: - Me is a monovalent metal, eg silver - 1 <x ≤ 6 - 1 <n ≤ 6 - n> x. The material of claim 1, further comprising one or more compounds of the composition Cu _m P ₂ O _{5 + m} (II) where 1 <m ≤ 6. Material according to claim 1 or 2, characterized in that the material - a continuous phase of the composition Cu _m P ₂ O _{5 + m} (II) as defined in claim 2 and - one or more disperse phases of the composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) as defined in claim 1 or consisting of - a continuous phase of the composition Cu _m P ₂ O _5-m (II) as defined in claim 2 and - one or more disperse phases of composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) as defined in claim 1. Material according to one of claims 1 to 3, characterized in that the material - a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and - a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a disperse phase of the composition comprising Ag ₂ Cu ₃ P ₂ O ₉ (Ib) or from - a continuous phase of the composition Cu ₄ P ₂ O ₉ (IIa) and - a disperse phase of the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and / or a disperse phase of the composition Ag ₂ Cu ₃ P ₂ O ₉ (Ib). Material according to claim 4, characterized in that the proportion of the silver in the disperse phase of the composition (Ia) or (Ib) is 1 mol% to 10 mol%, preferably 5 mol%, based on the content of copper in the continuous phase of the composition (IIa). Use of a material according to one of claims 1 to 5 as active material for an electrode of a galvanic element. Chemical compound of composition Me _x Cu _{nx / 2} P ₂ O _{5 + n} (I) where: - Me is a monovalent metal, eg silver - 1 <x ≤ 6 - 1 <n ≤ 6 - n> x. A chemical compound according to claim 7 having the composition Ag ₂ Cu ₂ P ₂ O ₈ (Ia) or Ag ₂ Cu ₃ P ₂ O ₉ (Ib). Use of a chemical compound as defined in claims 7 and 8 as an active material for an electrode of a galvanic element or as a constituent of an active material, in particular an active material according to any one of claims 1 to 5, for an electrode of a galvanic element. A process for producing a material as defined in any of claims 4 and 5 or a chemical compound as defined in claim 8, comprising the steps of: providing a mixture comprising the starting materials copper oxide CuO a phosphate ion-containing thermally decomposable salt, eg diammonium hydrogen phosphate - a silver compound in a stoichiometry according to the desired composition - homogenizing the mixture, - single or multi-stage thermal treatment of the mixture, wherein the number, the respective duration and the respective temperature of the stages of the thermal treatment are chosen such that a chemical compound such as defined in claim 8 or a material as defined in any one of claims 4 and 5 is defined, - optionally homogenizing the thermally treated mixture. A mixture for producing an electrode for a galvanic element, consisting of or comprising (i) an active material as defined in claims 1 to 5 or one or more compounds as defined in any of claims 7 and 8, preferably one or both compounds of the group consisting from Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib), and (ii) one or more conductive additives and / or (iii) one or more binders and (iv) optionally one or more dispersants. Galvanic element, preferably battery, in particular for powering a medical implant with electronic components, comprising an electrode consisting of or comprising - a mixture as defined in claim 11, or - an active material as defined in claims 1 to 5, or - one or more Compounds as defined in any one of claims 7 and 8, preferably one or both compounds of the group consisting of Ag ₂ Cu ₂ P ₂ O ₈ (Ia) and Ag ₂ Cu ₃ P ₂ O ₉ (Ib). Galvanic element according to claim 14, characterized in that the galvanic element as the second electrode contains an electrode consisting of or containing metallic lithium as the active material. Medical implant, in particular for cardiac therapy, comprising a galvanic element, preferably a battery, according to claim 12 or 13.

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