FOIL-LIKE FUNCTIONAL MATERIAL AND METHOD FOR THE PRODUCTION THEROF

Abstract

A foil-like functional material (1) providing a predefined function and may be used for targeted physical, chemical, physicochemical, biological, technical and technological purposes, and in which is arranged a support medium (2), which comprises a total support volume, has a cross-sectional extent (7) of 100 m, like a matrix, and is formed from linear support elements (3a) and node-like support elements (3b), which form the substance components of the support medium (2) and pass through the total support volume to form a strip-like extent with interconnected partial volumes (5), situated therein and spanned by support elements (3) close by. The support elements (3) are sheathed with a first functional substance (4) which provides a first function. The remaining volume of the total support volume is filled with one second functional substance (6) which differs from the first function.

Claims

1. A foil-like functional material (1) fulfilling at least one predetermined function and can be used for physical, chemical, physicochemical and biological applications, in which a foil-like support medium (2) made of at least one construction material and comprising a total support volume with a cross-sectional extent (7)100 m is arranged, which is regarded as a matrix and is formed of linear support elements (3a), having a first dimension, and two second dimensions, the second dimensions being smaller than the first dimension, with the ratio of the first dimension to the two second dimensions being at least 50:1 and the ratio of the two second dimensions to one another being not less than 1:5 and not greater than 5:1, and node-shaped support elements (3b) which form the material components of the support medium (2) and penetrate the total support volume, to a band-shaped extent with interconnected partial volumes (5) of the total support volume spanned by neighboring support elements (3), wherein the linear support elements (3a) have distances from one another at least in sections, which are greater than 5:1 in relation to the first of the two second dimensions of the linear support elements (3a), wherein the linear support elements (3a) and the node-shaped support elements (3b) are sheathed with a first functional material (4) fulfilling a first function, and wherein the remaining volume of the total support volume formed by the interconnected partial volumes (5) is filled with at least one second functional material (6), which fulfills a second function that differs from the first function.

2. The foil-like functional material (1) according to claim 1, wherein at least one second functional material (6) covers the top side and/or the bottom side of the support medium (2).

3. The foil-like functional material (1) according to claim 1, wherein the line-shaped support elements (3a) of the support medium (2) are interwoven mutually perpendicular warp threads and weft threads forming a fabric.

4. The foil-like functional material (1) according to claim 1, wherein the first functional material (4) is a metal.

5. The foil-like functional material (1) according to claim 1, wherein the support medium (2) is a glass-fiber woven tape or a carbon-fiber woven tape or a mineral-woo-fiber woven tape or a polymer-fiber woven tape or a wire woven tape.

6. The foil-like functional material (1) according to claim 1, wherein at least one second functional material (6) comprises one of the substance mixtures selected from the group lithium/nickel oxide, lithium/manganese oxide, lithium/cobalt oxide and lithium/iron phosphate and optionally further additives, preferably carbon black.

7. A method for producing a foil-like functional material (1) according to claim 1, comprising the following steps: sheathing support elements (3) of a support medium (2) by applying to the support elements (3) a first functional material (4) which fulfills a first function, and filling the remaining volume of the total support volume formed by the interconnected partial volumes (5) with at least one second functional material (6) which fulfills a second function that differs from the first function.

8. The method according to claim 7, wherein the sheathing of the support elements (3) is carried out by metallizing the support elements (3).

9. The method according to claim 7, wherein the support medium (2) is a fabric tape.

10. The method according to claim 9, wherein the support medium (2) is one of a glass-fiber fabric tape, a carbon-fiber fabric tape, a mineral-wool-fiber fabric tape and a wire fabric tape.

11. The method according to claim 10, wherein the metallization of the support elements (3) is performed by physical vapor deposition of metal in a vacuum coating system or by thermal spraying or by hot dipping the support medium (2) in a molten metal bath.

12. The method according to claim 8, wherein the metallization of the support elements (3) is performed by chemical metal coating in a two-stage process, with the metallization of the support elements (3) comprising the steps of: seeding process, and metal coating process.

13. The method according to claim 8, wherein the metallization of the support elements (3) is performed by chemical metal coating in a three-stage process, with the metallization of the support elements (3) comprising the steps of: seeding process, metal coating process, and metal layer reinforcement process.

14. A foil-like functional material (1) fulfilling at least one predetermined function and can be used for physical, chemical, physicochemical and biological applications, in which a foil-like support medium (2) made of at least one construction material and comprising a total support volume with a cross-sectional extent (7)100 m is arranged, which is regarded as a matrix and is formed of linear support elements (3a), and node-shaped support elements (3b) which form the material components of the support medium (2) and penetrate the total support volume, to a band-shaped extent with interconnected partial volumes (5) of the total support volume spanned by neighboring support elements (3), wherein the linear support elements (3a) and the node-shaped support elements (3b) are sheathed with a first functional material (4) fulfilling a first function, and wherein the remaining volume of the total support volume formed by the interconnected partial volumes (5) is filled with at least one second functional material (6), which fulfills a second function that differs from the first function.

Description

[0083] Further details, features and advantages of embodiments of the invention result from the following description of exemplary embodiments with reference to the appended drawings, which show in:

[0084] FIG. 1: a basic schematic diagram of a foil-like functional material in cross section,

[0085] FIG. 2A: a schematic diagram of a simplest design of a matrix,

[0086] FIG. 2B: a schematic diagram of a matrix in a more disordered design than shown in FIG. 2A,

[0087] FIG. 2C: a scanning electron micrograph of an expanded polytetrafluoroethylene foilePTFEas an embodiment of a matrix as a support medium of a foil-like functional material,

[0088] FIG. 2D: a schematic diagram of a single-layer fabric as an embodiment of a support medium of a foil-like functional material,

[0089] FIG. 2E: a schematic diagram of a single-layer knitted fabric as an embodiment of a support medium of a foil-like functional material,

[0090] FIG. 2F: a scanning electron micrograph of a textile braid as an embodiment of a support medium of a foil-like functional material,

[0091] FIG. 3A: a basic schematic diagram of a foil-like functional material with a glass fabric in cross section,

[0092] FIG. 3B: a basic schematic diagram of an electrode foil according to the prior art in cross section,

[0093] FIG. 3C: a more detailed schematic diagram of a foil-like functional material in cross section,

[0094] FIG. 4A: a schematic diagram of an anode foil of an aluminum electrolytic capacitor with a glass fabric as a support medium in cross section,

[0095] FIG. 4B: a scanning electron micrograph of an anode foil of aluminum-electrolytic capacitor as representative of a functional foil according to the prior art in cross section,

[0096] FIG. 5A: a scanning electron micrograph of a conventional electrode for lithium-ion-batteries according to the prior art in cross section

[0097] FIG. 5B a schematic diagram of a foil-like electrode for lithium-ion-batteries with a textile support medium whose support elements are sheathed with aluminum, in cross-section, and

[0098] FIG. 6 a schematic diagram of a foil-like graphite electrode for lithium-ion-batteries with a copper-plated steel wire mesh as the support medium in cross-section.

[0099] FIG. 1 shows the basic structure of a foil-like functional material 1 in cross section. The foil-like functional material 1 has a support medium 2 consisting of a construction material and is formed as a matrix, the support elements 3 of which are designed as linear support elements 3a and as node-shaped support elements 3b and are sheathed with a first functional material 4 that fulfills a first function. Partial volumes 5 are spanned by the support elements 3a, 3b and filled with a second functional material 6, which performs at least one second function that differs from the first function. Depending on the application, the foil-like functional material 1 can also be referred to as foil-like electrode material 1 or as foil-like anode material 1 or as anode foil 1, or as foil-like cathode material 1 or as cathode foil 1, wherein the top and/or bottom side of the foil-like functional material 1 is then completely covered with the second functional material 6.

[0100] FIG. 2A shows schematically a simple basic embodiment of a support medium 2. Line-shaped support elements 3a and node-shaped support elements 3b are only located in mutually perpendicular planes. The support elements 3a and 3b span open partial volumes 5 which are interconnected and open on all sides. The support medium 2 is shaped foil-like, i.e. its x- and y-dimensions are much greater than its dimension in the z-direction, which is referred to as the cross-sectional extent 7 of the support medium 2. This condition always applies in the context of this invention, even if not always clearly illustrated in the figures. A support medium 2 is always constructed of two different types of support elements 3a and 3b, which include all structural elements contained in the support medium 2 and consist of the construction material. Linear support elements 3a are, for example, yarns in textiles or polymer threads in expanded polymers or linear structures, molecular fibers, spun fibers, textile fibers, filaments or other linear structures. Node-shaped support elements 3b are, for example, crossed threads of warp yarns and weft yarns in textile fabrics, intertwined filaments, a compact concentration of thread-like elements of the construction material, a point-shaped collection of elements of the construction material, for example in expanded polymers, three-dimensional fabric piles of the construction material and the like. The support elements 3 span interconnected partial volumes 5 which are open laterally and in particular toward the top and the bottom of the support medium 2. In the special case of the support medium 2 in FIG. 2A, the line-shaped support elements 3a and the node-shaped support elements 3b are always located in mutually perpendicular parallel planes.

[0101] Reference is made to a support medium 2 if the support medium 2 extends in three dimensions. Accordingly, reference is already made to a support medium 2 when all support elements 3 are practically in a single plane, which however no longer represents a two-dimensional area, but has a three-dimensional extent.

[0102] FIG. 2B shows a schematic diagram of a more disordered arrangement of a support medium 2 compared to the support medium 2 from FIG. 2A, representing one of the more typical forms of a support medium 2 for a foil-like functional material. This schematic diagram is intended to show that a support medium 2 need not have an ordered structure. The distribution of the linear support elements 3a and the node-shaped support elements 3b can in fact be disordered. Also, in the case of FIG. 2B, the support elements 3a and 3b span interconnected open partial volumes 5 which are open on all sides.

[0103] FIG. 2C shows a scanning electron micrograph, hereinafter referred to as SEM, in a plan view of an expanded polytetrafluoroethylene foil, also referred to as ePTFE, as a support medium 2. Line-shaped support elements 3a and node-shaped support elements 3b are disordered. The line-shaped beam elements 3a are oriented molecular fibers, whereas the node-shaped support elements 3b represent point-shaped clusters of polytetrafluoroethylene material components. The oriented molecular fibers, i.e. the line-shaped support elements 3a and the node-shaped support elements 3b, span partial volumes 5. The partial volumes 5 are interconnected.

[0104] FIG. 2D shows schematically a support medium 2 in the form of a textile fabric. The linear support elements 3a are yarns, threads or wires, which are referred to as warp threads and weft threads. The node-shaped support elements 3b are those areas where warp threads and weft threads cross. The support medium 2 in the form of a textile fabric in FIG. 2D is an example of all the support elements 3 located essentially in a single plane, although the support medium 2 has a three-dimensional extent. Open partial volumes 5 are spanned between the linear support elements 3a, the warp threads and the weft threads and their crossing points, namely the node-shaped support elements 3b. The distance resulting from the crossing of warp thread and weft thread corresponds to the cross-sectional extent 7 of the support medium 2.

[0105] FIG. 2E shows a schematic diagram of a top view of a textile knitted fabric as support medium 2. Such foil-like textile structures can be industrially produced from thread systems by forming stitches on a knitting machine; they therefore are part of knitwear. In this case, the linear support elements 3a are textile threads, the node-shaped support elements 3b are formed by intertwined threads. Open partial volumes 5 are spanned between the linear support elements 3a formed by textile threads, and their intertwined portions of the textile threads, i.e. the node-shaped support elements 3b. The distance resulting from the intertwined superimposed portions of the textile threads corresponds to the cross-sectional dimension 7 of the support medium 2.

[0106] FIG. 2F depicts an SEM of a plan view of a mesh as a support medium 2. The linear support elements 3a are formed from textile threads, the node-shaped support elements 3b are formed from crossings or accumulations of textile threads. In this example, the distribution of the linear support elements 3a and the node-shaped support elements 3b is stochastic. Open partial volumes 5 are spanned between several intersecting textile threads, the node-shaped support elements 3b, and a relatively large number of textile threads, i.e. the linear support elements 3a.

[0107] FIG. 3A shows schematically a foil-like functional material 1, consisting of a textile support medium 2, in cross section. The linear support elements 3a, the textile warp threads and weft threads and their crossing areas, the node-shaped support elements 3b of the textile support medium 2, a textile fabric, are sheathed by a first functional material 4, which fulfills a first function. The partial volumes 5 are filled with a second functional material 6, which fulfills at least one second function that differs from the first function. The top side and bottom side of the support medium 2 are covered with the second functional material 6. The support medium 2 is a glass fabric, the basic structure of which is shown in FIG. 2D. A first functional material 4, which fulfills a first function, is applied both to the linear support elements 3a and to the node-shaped support elements 3b. The first functional material 4 envelops the linear and the node-shaped support elements 3a and 3b. D.sub.A denotes the cross-sectional extent 7 of the support medium 2, whose support elements 3 are sheathed with the first functional material 4.

[0108] D.sub.vfFM denotes the thickness of the foil-like functional material 1, the top and bottom sides of which are coated with the second functional material 6.

[0109] FIG. 3B shows as a comparison to the foil-like functional material 1 shown in FIG. 3A a cross section of a conventional electrode foil according to the prior art with a metal foil 2 or a metalized foil, preferably a metalized polymer foil, as the support medium 2. The same functional material 6 with which the open partial volumes 5 the foil-like functional material 1 shown in FIG. 3A are filled and with which the top and bottom sides have been adherently coated, is applied on both sides of the support medium 2. D.sub.TF corresponds here to the thickness of the metal foil 2, which both acts as a support medium and has the function to charging and discharging the charge carriers. D.sub.VF corresponds to the thickness of the electrode foil. The thickness D.sub.VF of the electrode foil from FIG. 3B corresponds to the thickness D.sub.VfFM of the foil-like functional material 1 from FIG. 3A that was coated on both sides with the second functional material 6. D.sub.vfFM is hence equal to D.sub.VF.

[0110] FIG. 3C shows in cross section a detailed schematic diagram of the foil-like functional material 1 shown in FIG. 3A. The second functional material 6 fulfills at least one active and at least one non-active function. The second functional material 6 has open pores 8 as its inner structure, which however do not correspond to the partial volumes 5.

[0111] In principle, the foil-like functional material 1 according to the invention is distinguished by a large volume or mass fraction of the second functional material 6 in relation to the total volume or the total mass of the foil-like functional material 1. This is of important for the use of the foil-like functional material 1, because a large proportion of the total volume or the total mass of the foil-like functional material 1 is thus taken up by the second functional material 6, which fulfills an active function.

[0112] FIG. 4A shows an anode foil 1 for an aluminum-illustrated electrolytic capacitor in cross-section, i.e. a foil-like functional material 1 in an application as an electrode, wherein the support medium 2 is a glass fabric, as shown in FIG. 2D. The support elements 3 are sheathed with aluminum as the first functional material 4. Depending on the electrode type, the layer thickness can be in a range from 0.2 m to 4 m. Highly porous aluminum is introduced into the partial volumes 5 as the second functional material 6. The highly porous aluminum is also disposed on the top and bottom sides of the support medium 2. As seen in the enlarged detail shown on the right-hand side of FIG. 4A, the highly porous aluminum consists of a highly porous aluminum body 9 and of aluminum oxide layers 10 which have formed on the surfaces of the highly porous aluminum body 9, as well as open pores 8. Open pores 8 in the second functional material 6 are used to retain an electrolyte when the foil-like functional material 1 is used as an electrode of an electrical energy store. The aluminum oxide layer 10 representing the dielectric-layer of the aluminum electrolytic capacitor was generated on the surface of the highly porous aluminum body 9 by anodic oxidation. The highly porous aluminum body fulfills a non-active function, namely to charging and discharging charge carriers. The aluminum oxide layer 10 fulfills the active function of storing the charge carriers, i.e. charge carrier storage as a characteristic function of the application of the foil-like functional material 1 as the anode foil 1 for an aluminum-electrolytic capacitor. The open pores 8 are filled with an electrolyte and hence fulfill a non-active function by providing the volume for the electrolyte. The highly porous aluminum is preferably introduced into the partial volumes 5 and applied to the top and bottom sides of the support medium 2 by vacuum coating processes.

[0113] The quantity of aluminum, as the first functional material 4 sheathing the support elements 3, must be sized to meet the electrical wiring requirements, generally corresponding to an aluminum layer with a thickness between 0.2 m and 4 m. To ensure these requirements, for example, a glass fabric with twenty-two warp threads and weft threads per centimeter is used as the support medium 2. The fabric is flattened. The compression creates warp threads and weft threads with a width of 180 m and a thread height of 15.5 m. The first functional material 4 has been applied to these threads in the form of an aluminum layer, which has excellent electrical conduction properties. The support medium is thus metallized with the first functional material 4, i.e. aluminum, wherein the layer thickness of the aluminum applied to and sheathing the warp- and weft threads is on average about 2.5 m. This results in a cross-sectional extent 7 of the metallized support medium 2 of 36 m. Highly porous aluminum was deposited as the second functional material in the partial volumes 5 of the metallized support medium 2, i.e. in the mesh spaces of the glass fabric. Highly porous aluminum, each with a thickness of 32 m, was also deposited on the top and bottom sides of the foil-like functional material 1. The total thickness of the anode foil 1 is 100 m.

[0114] The support medium 2 metallized with aluminum as the first functional material 4 occupies a volume of 0.00156 cm.sup.3 per square centimeter of the base area of the anode foil 1. The total volume of the anode foil 1 per square centimeter base area is 0.01 cm.sup.3. The volume fraction of the support medium 2 and the first functional material is thus approximately 15.6%, the volume fraction of the second functional material 6, namely the highly porous aluminum, is approximately 84.4%.

[0115] Conversely, in a conventional anode foil 1, the support medium 2 takes up a considerably larger proportion of the total volume of the anode foil 1. A possible embodiment of such a conventional anode foil 1 according to the prior art is shown in cross section in FIG. 4B. This anode foil 1 has been prepared from a high-purity aluminum foil by electrochemical etching, with the interior part remaining unprocessed. This proportion represents the support medium 2 of the anode foil 1. In a conventional anode foil 1 having a thickness of 100 m, as shown in the SEM in FIG. 4B, the thickness of the support medium 2, which was not electrochemically etched, is about 28.6 m and the electrochemically etched area is about 71.4 m, which corresponds to a thickness of this area of about 35.7 m per side. The anode foil 1 is created after a so-called forming process, i.e. an electrochemical or anodic oxidation. The support medium 2 performs the support function and is at the same time responsible for charging and discharging charge carriers. The electrochemically etched area performs the actual capacitor function, i.e. the storage of charge carriers. The ratio of the thickness D.sub.TF between the support medium 2 and the layer performing the actual capacitor function can be estimated to be approximately one to two and a half, i.e. 1 to 2.5.

[0116] The support medium 2 of the conventional anode foil 1 occupies a volume of 0.00286 cm.sup.3 per square centimeter. This corresponds to approximately 28.6% of the total volume of the conventional anode foil 1 according to the prior art. The area of the conventional anode foil 1 performing the capacitor function occupies a volume of 0.0032 cm.sup.3 per square centimeter of base area. This corresponds to approximately 71.4% of the total volume. In contrast, with the solution according to the invention, 84.4% of the total volume is available for performing the capacitor function, i.e. for storing charge carriers.

[0117] In the case of the anode foil 1 for an aluminum-electrolytic capacitor, the proportion of the volume of the second functional material 6 available for fulfilling the capacitor function can be further increased up to 94% by further reducing for example the number of warp threads and weft threads, or in place by using of threads having a diameter of 4 m instead of threads having a diameter of 5 m.

[0118] FIG. 5A shows an SEM of a cathode 1 of a lithium-ion-cell according to the prior art in cross section. The term cathode is always to be understood in the context of discharging the cell. The electrode is one of the so-called lithium-metal-oxide-electrodes. Such a conventional cathode 1 consists of an intrinsically, electrically poorly conductive active material such as, for example, lithium and nickel oxide, lithium and manganese oxide, lithium and cobalt oxide or lithium and iron phosphate, as well as a number of additives, that fulfills non-active functions as a functional material. Carbon black is an important additive for producing electrical conductivity. An aluminum foil is used here as the support medium 2.

[0119] The anode of a lithium-ion battery, which is not shown here, is made of graphite and is therefore referred to as a graphite electrode. The support medium 2 for the cathode, which is also referred to as a current collector, is an aluminum foil 2 and a copper foil for the unillustrated anode. The support medium 2 in the application shown in FIG. 5A, is also an aluminum foil with a thickness of 30 m. The use of such an aluminum foil is to be regarded as state of the art. Furthermore, solutions exist in the prior art, wherein the support medium 2 is an aluminum foil with a thickness of 15 m. The aim is to use 10 m thick aluminum foils as the support medium 2. The total thickness of the cathode foil is approximately 194 m.

[0120] FIG. 5B shows schematically the application of a foil-like functional material 1 as a cathode 1 in a lithium-ion-cell in cross-section. The foil-like functional material 1 has a three-dimensional textile fabric as the support medium 2 in the form of a glass fabric, with 18 warp threads and 18 weft threads per centimeter. The warp and weft threads of the linear support elements 3a have an approximately round cross section with a diameter of approximately 35 m. The areas where the warp threads and the weft threads intersect form the node-shaped support elements 3b. Aluminum is applied as a first functional material 4 to sheath the support elements 3a and 3b. The layer thickness of the applied aluminum is approximately 7 m. The partial volumes 5 of the metallized support medium 2, i.e. the mesh spaces 5 between the warp threads and the weft threads, are filled with the second functional material 6. Top-and bottom sides of the foil-like functional material 1 are each coated with the second functional material 6 having a thickness of 55 m. The second functional material 6 consists of a mixture of lithium-iron phosphate, conductive carbon black, solvents, binders and additives. The novel cathode 1 was calendared. Calendaring refers to a process where the foil-like functional material 1 is passed sequentially through the gaps between a plurality of superimposed heated and polished rollers, which causes compression and solidification of the foil-like functional material 1, i.e. the cathode 1. The thickness D.sub.VfFM of the cathodes 1 after these processes is 194 m, allowing an easy comparison with the prior art solution shown in FIG. 5A.

[0121] The support medium 2 in the form of an aluminum foil of the cathode 1 according to the prior art shown in FIG. 5A has a volume of 0.003 cm.sup.3 per square centimeter. This corresponds to approximately 15.5% of the total volume of the cathode 1. The second functional material 6 applied to both sides of the support medium 2 takes up a volume of 0.0164 cm.sup.3 per square centimeter of base area. This corresponds to approximately 84.5% of the total volume.

[0122] When using a 15 m thick aluminum foil as a support medium 2, the volume of the second functional material 6 would be approximately 0.018 cm.sup.3. This would correspond to approximately 92.3% of the total volume of the cathode 1. When using a 10 m thick aluminum foil as the support medium 2, the volume of the second functional material 6 would be approximately 0.0184 cm.sup.3. This would correspond to approximately 94.85% of the total volume of the cathode 1.

[0123] With the solution of a cathode 1 shown in FIG. 5B using a foil-like functional material, the volume of the support medium 2, the support elements 3 of which are sheathed with the first functional material 4, takes up approximately 4.7% of the total volume of the cathode 1. Thus, the proportion of the volume of the second functional material 6 is approximately 95.3% of the total volume of the cathode 1. In comparison, with a solution from the prior art shown in FIG. 5A, even when using a 10 m thick aluminum foil as the support medium 2, which has thus far not been technically feasible, only a proportion of the second functional material 6 of the total volume of the cathode 1 of at most 94.85% is possible.

[0124] FIG. 6 shows schematically in cross-section an anode 1 of a lithium-ion-cell using a foil-like functional material. The anode 1 has a steel wire mesh as the support medium 2, with twenty warp wires and twenty weft wires per centimeter. Warp and weft threads are therefore monofilaments and have a diameter of about 15 m. A compact copper layer with a thickness of approximately 4 m is applied on and sheathes the support elements 3 (wires as linear support elements 3a and their crossing points as node-shaped support elements 3b) as the first functional material 4. The partial volumes 5 spanned by the support elements 3 are filled with the second functional material 6. The top and bottom sides of the foil-like functional material 1 are each coated with the second functional material 6 with a thickness of 75 m. The second functional material is graphite with open pores. The anode 1 was calendared, as is also customary in the prior art. The thickness D.sub.VfFM of the anode 1 is 188 m after calendaring.

[0125] An anode for a lithium-ion-accumulator according to the prior art comparable to the anode 1 shown in FIG. 6 consists of graphite adherently applied to a copper foil. When using a 15 m thick copper foil, this foil takes up a volume of 0.0015 cm.sup.3 per square centimeter of anode base. This corresponds to approximately 8.0% of the total volume of the anode. The graphite, i.e. the second functional material 6, adherently applied to the copper foil, occupies a volume of 0.0173 cm.sup.3 per square centimeter of anode base area. This corresponds to approximately 92.0% of the total volume of the anode. When using a 6 m thick copper foil, this foil takes up a volume of 0.0006 cm.sup.3 per square centimeter of anode base area. This corresponds to approximately 3.2% of the total volume of the anode. The graphite, i.e. the second functional material 6, adherently applied to the copper foil, occupies a volume of 0.0182 cm.sup.3 per square centimeter of anode base area. This corresponds to approximately 96.8% of the total volume of the anode.

[0126] In comparison, with the solution shown in FIG. 6, the support medium 2, whose support elements 3 are sheathed with a compact copper layer having a thickness of approximately 4 m, occupies a volume of approximately 0.0002 cm.sup.3 per square centimeter of anode base, which accounts for about 1.1% of the total volume of the anode. The second functional material 6, i.e. the graphite, takes up a volume of approximately 0.0186 cm.sup.3 per square centimeter of anode base area. The proportion of the second functional material 6 in the total volume of the anode 1 is thus 98.9%.

[0127] A cathode 1 or an anode 1 according to the invention can be produced using a foil-like functional material as follows:

[0128] A textile fabric is used as the support medium 2. The support elements 3, i.e. the warp and weft threads as line-shaped support elements 3a and the intersection area of warp and weft threads as node-shaped support elements 3b, are adherently sheathed commensurate with the application with an electrically conductive metal, for example aluminum or copper, as the first functional material 4. The layer thickness is between 1 m and 4 m. According to the concept of the invention, the support medium 2 renders the mechanical stability of the foil-like functional material 1 while the first functional material 4 fulfills the non-active function of charging and discharging the charge carriers. Nevertheless, the first functional material 4 can also contribute to increasing the mechanical stability of the foil-like functional material 1. The coating of the support elements 3 with the first functional material 4 can be performed using vacuum PVD-processes or thermal spray processes, with a thermal post-treatment, as already described, optionally carried out depending on the implementation of the method, by using the afore-described chemical and electrochemical methods or by hot-dipping the support medium in a molten metal bath, in which case the melting temperature of the metal must be below the temperature which would lead to the destruction of the textile fabric. Subsequently, the partial volumes 5 spanned by the support elements 3 sheathed with the first functional material 4 are filled with the second functional material 6. This produces a foil-like functional material 1, which is subsequently processed into a cathode 1 or anode 1 using methods known from the prior art.

[0129] To produce a cathode 1 or anode 1, the top and bottom sides of the foil-like functional material 1 are coated with the second functional material 6. The second functional material 6 is, for example, a coating compound known from the prior art, referred to as slurry. The second functional material fulfills as an active function storing charge carriers and as a non-active function charging and discharging of charge carriers to/from the storage locations in the second functional material 6. It can also contribute to mechanical stabilization. The coating compounds are stored in a reservoir where the constituents can also be mixed, and is applied on both sides of the foil-like functional material 1 by an application system, i.e. an applicator.

[0130] The processes following the coating, such as drying, can take place in accordance with the prior art.

[0131] A textile fabric suitable as a support medium 2 for a foil-like functional material 1 according to the invention should not necessarily be distinguished by a high density of warp and weft threads, but sufficiently large partial volumes 5 should be spanned by the warp-and weft threads as linear support elements 3a as well as by their crossover points as node-shaped support elements 3b, however under the proviso that the mechanical stability of the textile fabric is sufficiently high for the support function.

[0132] This means that a textile fabric suitable as a support medium 2 need not necessarily have to be characterized by a particularly small cross-sectional dimension 7 or a particularly small mesh size.

[0133] However, in many cases, it is useful to keep the diameter of the filaments, of which yarns for warp threads and weft threads for a support medium 2 are composed, as small as possible in order to keep the volume fraction of the support medium 2 with respect to the total volume of the foil-like functional material 1 sufficiently small, however with the proviso that the mechanical stability of the textile fabric is sufficiently high for the support function.

[0134] An anode foil for an aluminum-electrolytic capacitor will now be described below: The anode foil has a thickness of 100 m. The support medium 2 is a glass fabric (EC5 5.5 1x0 5 5.5 1x0). This glass fabric has a thread density of 22 warp threads and 22 weft threads per cm. The warp threads and weft threads each consist of filaments with a diameter of 5 m , wherein the thread width is 160 m and the thread height is 17.5 m. A 2.5 m thick aluminum layer is applied to the warp threads and weft threads as the first functional material 4. The metallized glass fabric is characterized by the following dimensions: [0135] The cross-sectional extent 7 of the metallized fabric is 0.004 cm, i.e. 40 m. [0136] The meshes of the metallized glass fabric have a size of approximately 0.031 cm0.031 cm. [0137] The metallized glass fabric has a volume of approximately 0.004 cm.sup.3 per cm.sup.2 of the glass fabric base area. [0138] About 38.36% of the volume of the foil-like functional material 1 is taken up by the metallized glass fabric, the sum of the open, interconnected partial volumes 5 spanned by the linear and node-shaped support elements comprises 61.64% of this volume of the foil-like functional material 1.

[0139] The partial volumes 5 are filled with highly porous aluminum as the second functional material 6. A foil-like functional material 1 is formed. To form the anode foil, the top and bottom sides of the foil-like functional material 1 are also coated with highly porous aluminum. The anode foil 1 produced in this way is characterized by the following dimensions: [0140] The sum of the volume of the highly porous aluminum, i.e. the second functional material, applied to the top and bottom sides of the foil-like functional material is 0.006 cm.sup.3 per square centimeter of anode foil base area. [0141] The total volume of the highly porous aluminum, i.e. the second functional material which fulfills the function of storing charge carriers characteristic of an electrolytic capacitor, is 0.0085 cm.sup.3 per square centimeter of anode foil base area. [0142] The highly porous aluminum takes up 85% of the total volume of the anode foil.

[0143] In another anode foil for an aluminum-electrolytic capacitor, a glass fabric having warp and weft threads is used is used as a support medium 2. The glass fabric consists of approximately 102 filaments with a diameter of 5 m and with a thread density between 15 to 20 threads per cm. A significant reduction in the cross-sectional dimension 7 is achieved by compressing the thread cross-section and smoothing the thread curvature with biaxial tension. The reduced cross-sectional dimension 7 can be between 25 m to 35 m, with the meshes being within a range from 325 m to 550 m325 m to 550 m. With this anode foil, the proportion of the volume of the foil-like functional material 1 occupied by the metallized glass fabric, i.e. the metallized support medium 2, can be reduced to 13.5%.

[0144] In another anode foil for an aluminum-electrolytic capacitor, a glass fabric having warp and weft threads is used is used as a support medium 2. The glass fabric consists of approximately 51 filaments with a diameter of 4 m and the thread density between 20 to 25 threads per cm. A significant reduction in the cross-sectional dimension 7 is achieved by compressing the thread cross-section and smoothing the thread curvature with biaxial tension. The reduced cross-sectional dimension 7 can be between 10 m and 18 m, with the meshes being within a range of 300 m to 425 m300 m to 425 m. With this anode foil, the proportion of the volume of the foil-like functional material 1 occupied by the metallized glass fabric, i.e. the metallized support medium 2, can be reduced to 5.5%.

[0145] A positive or negative electrode for lithium-ion batteries will now be described below: A textile fabric with a warp and weft consisting of approximately 102 filaments having a diameter of 5 m and a thread density is between 12 to 18 threads per cm was used as a support medium 2. The cross-sectional extent 7 of the support medium 2 can be up to 100 m. The size of the meshes can be within the range of 400 m to 725 m400 m to 725 m. The support elements 3 of the support medium 2, i.e. warp and weft as line-shaped support elements 3a and a crossing area of warp and weft as node-shaped support elements 3b, are adherently sheathed with an electrically conductive metal, aluminum or copper, as the first functional material 4 commensurate with the intended use, for example as positive or negative electrode. The proportion of the volume occupied by the metallized support elements 3 is approximately 6% of the total volume spanned by the support medium 2.

[0146] With yarns consisting of 51 filaments with a diameter of 4 m and having an almost round cross-section, support media 2 can be produced from textile fabrics and have a thread density of between 17 and 22 threads per centimeter, which have a cross-sectional extent 7 of up to 65 m. The size of the meshes is within the range of 425 m to 600 m425 m to 600 m. The proportion of the volume taken up by the metallized support elements 3 is then approximately 3% of the total volume spanned by the support medium 2.

LIST OF REFERENCE SYMBOL

[0147] 1 foil-like functional material, foil-like anode material or anode foil, foil-like cathode material or cathode foil [0148] 1 conventional electrode foil according to the prior art, anode or cathode according to the prior art, foil-like functional material according to the prior art, anode foil for electrolytic capacitors according to the prior art, [0149] 2 support medium [0150] 2 support medium according to the prior art; metal support foil, metallized polymer foil, aluminum foil according to the prior art [0151] 3 support element [0152] 3a linear support element [0153] 3b node-shaped support element [0154] 4 first functional material [0155] 5 partial volumes, mesh space of a fabric [0156] 6 second functional material [0157] 7 cross-sectional extent of the support medium 2 [0158] 8 open pores [0159] 9 aluminum body [0160] 10 aluminum oxide layers [0161] D.sub.A cross-sectional extent of the support medium 2 [0162] D.sub.vfFM thickness of the coated foil-like functional material 1 [0163] D.sub.TF thickness of the support foil 2 [0164] D.sub.VF thickness of the electrode foil