Conductive composite, method for producing same, solid-state accumulator, battery, and vehicle

Abstract

The invention relates to a conductive composite (1) comprising an electrically conductive carrier material which has pores (2) and which is provided at least partially with a lithiophilic material (3) inside the pores (2). The conductive composite according to the invention is characterized in that the carrier material is formed by carbon-based fibers.

Description

[0001] Conductive composite, method for its production, solid-state accumulator,

[0002] Battery and vehicle

[0003] The invention relates to a conductive composite of the type defined in more detail in the preamble of claim 1, a method for its production, a solid-state accumulator with such a conductive composite, a battery comprising such a solid-state accumulator, and a vehicle with such a battery.

[0004] Solid-state batteries, also known as all-solid-state batteries (ASSBs), offer significant potential for increasing performance compared to conventional lithium-ion batteries. However, several hurdles must be overcome, particularly regarding the use of pure lithium for electrode formation.

[0005] Power collectors are created.

[0006] Lithium metal anodes undergo significant volume changes during the charging and discharging of a corresponding battery. This compromises the stability and safety of the battery or accumulator. Solid-state batteries, in particular, present the problem that only a relatively small amount of space is available to compensate for these volume changes. Furthermore, the resulting expansion and contraction increase the risk of individual battery components separating from one another.

[0007] Due to its low reduction potential, lithium metal undergoes undesirable reactions during continuous charging and discharging, leading to the formation of so-called "dead" lithium. This process promotes the growth of lithium metal dendrites both on the metal surface and within the grain boundaries of the solid electrolyte, increasing the risk of sudden internal short circuits. The formation and growth of these lithium deposits is also known as lithium plating.

[0008] Furthermore, the production of lithium current collectors or electrodes, especially those manufactured as thin films with a thickness of less than 100 pm, is challenging. The thinner the film needs to be, the more complex and therefore more expensive the manufacturing process becomes.

[0009] From US patent 2021 / 0408523, an anode for a solid-state battery or solid-state accumulator and a method for manufacturing the anode are known. The solid-state accumulator comprises a cathode layer, an anode layer, and a solid electrolyte located between the cathode and anode layers. The anode layer includes an anode collector and a lithium distribution layer on the anode collector. The lithium distribution layer, in turn, comprises a metal capable of bonding with or alloying with lithium. The lithium distribution layer connects the anode collector to the solid electrolyte.

[0010] Furthermore, US patent 2023 / 0361311 discloses a current collector for electrochemical cells that transports lithium ions. The current collector comprises a current collector substrate and a lithophilic material, comprising an element from the group consisting of indium, lead, bismuth, gold, and combinations thereof. By using a suitable lithophilic material, i.e., a substance that tends to form compounds or alloys with lithium, the bond between the current collector and the lithium is improved, thus counteracting delamination and a decrease in cell performance.

[0011] Furthermore, US patent 2023 / 0045571 Al discloses a negative electrode coated with a lithophilic material and a method for manufacturing the electrode. The negative electrode comprises a current collector, which in turn includes a porous structure having internal pores or a through-hole extending from an upper surface to a lower surface of the current collector. A lithophilic material is applied to the surface of the porous structure. The portion of the negative electrode's current collector facing the positive electrode of a corresponding battery is free of the lithophilic material. The negative electrode and current collector presented in the patent are characterized by improved short-circuit performance due to reduced lithium dendrite growth.

[0012] Furthermore, DE 200 10080 Ul discloses a solid-state ionic battery. The battery comprises a solid electrolyte and an electrode, comprising a material with a carbon nanostructure, in particular in the form of nanofibers. The battery can be lithium-based.

[0013] The present invention is based on the objective of providing means by which it is possible to further improve solid-state accumulators compared to the prior art.

[0014] According to the invention, this problem is solved by a conductive composite having the features of claim 1, a method for its production having the features of claim 7, and a solid-state battery having the features of claim 10. Advantageous embodiments and further developments, as well as a battery comprising such a solid-state battery and a vehicle with such a battery, are described in the dependent claims.

[0015] A conductive composite of the generic type, comprising a porous, electrically conductive carrier material which is at least partially provided within the pores with a lithiophilic material, is further developed according to the invention by forming the carrier material with carbon-based fibers. Current collectors for electrodes of solid-state batteries or corresponding electrodes themselves can be manufactured from the conductive composite. The use of carbon-based fibers as the carrier material for the lithiophilic material gives the conductive composite outstanding properties. For example, the volume change during charging and discharging of a corresponding solid-state battery can be reduced to a minimum. Furthermore, corresponding electrodes can be manufactured with minimal effort, thus reducing costs.The energy density and safety of a corresponding solid-state battery can be increased or improved by using the conductive composite according to the invention to form the respective electrodes. The reduction of lithium is limited to the immediate vicinity of the carbon-based fibers. This allows the problems described above in connection with the use of lithium-metal electrodes to be at least mitigated or even completely eliminated.

[0016] An advantageous further development of the conductive composite according to the invention provides that the lithiophilic material is arranged exclusively within the pores of the carbon-based fibers. This results in lithium plating, or the growth of pure lithium, occurring exclusively within the pores of the carbon-based fibers. This further reduces the volume change during charging and discharging of a solid-state battery comprising the conductive composite. Consequently, energy density and safety can be further improved. This is based on the fact that, during the charging of a corresponding solid-state battery, lithium ions are extracted from the lithiophilic material within the pores of the carbon-based fibers, reacting or alloying to form solid lithium exclusively within the pores.

[0017] The starting material used, namely the aforementioned carbon-based fibers, is widely available and inexpensive. Due to this good availability, economies of scale can be exploited, enabling large-scale industrial production of corresponding solid-state accumulators, electrodes, or current collectors based on the conductive composite according to the invention. The conductive composite according to the invention thus functions as both a current collector and the active material of the corresponding electrode. This eliminates the need for additional costly components, such as copper foils, as current collectors. Consequently, manufacturing costs can be reduced even further.

[0018] Solid-state batteries, which have electrodes or current collectors made of the conductive composite according to the invention, are also characterized by a high gravimetric energy density. With a porosity of 40% of the carbon-based fibers, a specific capacity of the anode section of approximately 970 mAh / g can be achieved. With a porosity of 50%, an increase to approximately 1400 mAh / g is even possible. The expected capacity exceeds that of conventional anodes based on copper current collectors many times over, which typically only achieve a specific capacity of around 255 mAh / g. Furthermore, the volumetric energy density of solid-state batteries, which have electrodes or current collectors made of the conductive composite according to the invention, can also be increased.Thanks to the use of the conductive composite according to the invention, volumetric energy densities on the order of 1300 mAh / cm² are achieved. 3 possible. However, when using pure graphite, only volumetric energy densities on the order of 570 mAh / cm³ are achievable. 3 Possible. Volumetric energy density is a critical factor in the context of battery-electric vehicles. Corresponding solid-state batteries can therefore be manufactured with a smaller installation volume for the same capacity, allowing for more cells in the vehicle or a reduction in the vehicle's overall weight for the same capacity.

[0019] According to a further advantageous embodiment of the conductive composite according to the invention, the carbon-based fibers are formed by carbon nanofibers. This allows the advantageous effects already described above to be further enhanced.

[0020] A further advantageous embodiment of the conductive composite according to the invention further provides that the carbon nanofibers have a diameter of 15 pm, an electrical conductivity of 170 S / cm and / or a specific surface area of ​​120 m². 2 / g. The highest performance improvements were achieved by using appropriate carbon nanofibers to form the conductive composite according to the invention. The diameter, electrical conductivity, and specific surface area of ​​the carbon nanofibers can vary within the tolerances achievable with conventional measurement methods.

[0021] According to a further advantageous embodiment of the conductive composite according to the invention, the lithiophilic material is formed by a metal or semimetal configured to form an alloy or compound with lithium. This further restricts the lithium plating to the area within the pores of the carbon-based fibers or to the area immediately adjacent to the carbon-based fiber. Preferably, the lithiophilic material is formed by at least one of the following substances: gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, and / or zinc. Zinc or zinc compounds are particularly preferred as the lithiophilic material. This has yielded the best results regarding the performance improvements of corresponding solid-state batteries.

[0022] A process according to the invention for producing a conductive composite described above is characterized by the following process steps:

[0023] - Deposition of the lithiophilic material on the surface of the carbon-based fibers, such that the lithiophilic material is deposited on the carbon-based fibers both within the pores and on the outer sheath of the fibers; and

[0024] - selective removal of the lithiophilic material from the outer shell of the carbon-based fibers, leaving the lithiophilic material on the surface within the pores.

[0025] All conventional deposition methods can be used to deposit the lithiophilic material onto the surface of carbon-based fibers, preferably carbon nanofibers. However, chemical vapor deposition is particularly preferred. This method achieves a particularly reliable wetting of the surface of the carbon-based fibers with the lithiophilic material.

[0026] All established material removal methods can be used to selectively remove the lithiophilic material from the outer shell of carbon-based fibers. Etching is particularly preferred for this purpose. This allows for a highly targeted removal of the lithiophilic material from the outer shell of the carbon-based fibers, ensuring that the material is reliably removed from the outer shell while remaining within the pores.

[0027] A solid-state battery of this type, comprising a first electrode containing at least a portion of lithium, a second electrode, and a solid electrolyte arranged between the first and second electrodes, comprises, according to the invention, a second electrode which in turn comprises a conductive composite as described above. The advantages for solid-state batteries arising from the use of electrodes comprising the conductive composite according to the invention have already been described in detail above. Such solid-state batteries are also referred to in technical circles as "anode-free" or "anodeless," since the provision of the usual components used to form anodes can be dispensed with.

[0028] According to an advantageous embodiment of the solid-state battery according to the invention, the first electrode is configured as the anode and the second electrode as the cathode. Preferably, the designation of the anode and cathode refers to the process of discharging the battery or solid-state battery. In this context, the anode represents the negative terminal and the cathode the positive terminal. However, it would also be possible to provide the conductive composite according to the invention in the first electrode or the anode, which will be discussed in more detail below.

[0029] A further advantageous embodiment of the solid-state battery according to the invention provides that the pores of the carbon-based fibers are free of lithium in a discharged state of the battery. The discharged state of the battery can be present immediately after its manufacture. Alternatively, the solid-state battery can be charged and then discharged to achieve this discharged state. Thanks to the use of the conductive composite according to the invention for forming corresponding electrodes or current collectors, it is possible to avoid metallic accumulations of lithium in an electrode made from the conductive composite when the battery is discharged. This, in turn, further improves the performance and safety of the solid-state battery.

[0030] A further advantageous embodiment of the solid-state battery according to the invention provides that the first electrode is configured as the cathode, wherein the active material of the first electrode has the following chemical equation: LiaNibCocMdC , where M is selected from the group consisting of: manganese, aluminum, magnesium and zirconium, and wherein the following ratios are maintained: 0.8 < a < 1.2; 0.8 < b < 1.0; 0.0 < c < 0.2; and 0.0 < d < 0.2. When using the conductive composite according to the invention for forming electrodes, this facilitates not only the production of so-called half-cells, but also the production of full cells.

[0031] In this case, the first electrode can be either the anode or the cathode.

[0032] According to a further advantageous embodiment of the solid-state battery according to the invention, the solid electrolyte is selected from a group consisting of: sulfide-based electrolytes, oxide-based electrolytes, and halide-based electrolytes. By selecting the appropriate electrolyte, the physical properties of the solid-state battery can be specifically tailored to the respective application. Furthermore, all common solid electrolytes can be used, which enables particularly flexible manufacturing of the solid-state battery according to the invention. If a particular group of materials is unavailable, an available group can be used.

[0033] A battery of this type, comprising at least two individual cells, is further developed according to the invention in that each individual cell is formed by a solid-state accumulator as described above. Thus, several solid-state accumulators according to the invention can be connected to form a battery. The individual cells can be selectively connected in parallel and / or in series with each other. This allows a desired voltage and capacity to be set for the battery. The battery is a secondary battery.

[0034] A vehicle according to the invention has such a battery as described above. The battery is particularly preferably used to operate an electric drive unit. In this context, the battery can also be referred to as a traction battery. The vehicle can be any road vehicle such as a car, truck, van, bus, or the like. Generally, it can also be a rail vehicle, watercraft, or aircraft.

[0035] As mentioned at the outset, thanks to the use of the conductive composite according to the invention for forming corresponding electrodes or current collectors for solid-state batteries, it becomes possible to increase the capacity of a corresponding battery while maintaining the same volume, or conversely, to reduce the volume while maintaining the same capacity. This allows the overall weight of the vehicle to be reduced or the maximum achievable range of the vehicle to be increased.

[0036] Further advantageous embodiments of the conductive composite and the solid-state accumulator according to the invention also result from the exemplary embodiments which are described in more detail below with reference to the figures.

[0037] This shows:

[0038] Fig. 1 shows a schematic representation of carbon nanofibers used in a conductive composite according to the invention to form electrodes or current collectors, at various stages during production and in use;

[0039] Fig. 2 shows a schematic representation of a current collector in use, comprising carbon nanofibers, wherein the carbon nanofibers of a first current collector have no coating and those of a second current collector are coated with zinc within the pores;

[0040] Fig. 3 shows a schematic representation of a deposition process according to the invention of a lithiophilic material onto carbon nanofibers by means of chemical vapor deposition;

[0041] Fig. 4 shows a schematic representation of a process sequence according to the invention for the partial removal of the lithiophilic material exclusively from the outer shell of the carbon nanofibers;

[0042] Fig. 5 shows a schematic representation of a manufacturing process according to the invention for half-cells, comprising an electrode and a conductive composite according to the invention;

[0043] Fig. 6 shows a schematic representation of a manufacturing process according to the invention for full cells, comprising an electrode, having a conductive composite according to the invention;

[0044] Fig. 7 shows several diagrams illustrating the voltage profiles and cyclic power dissipation of solid-state batteries comprising electrodes made of different materials.

[0045] Material; and Fig. 8 a table showing various parameters of solid-state accumulators, which include electrodes made of different materials.

[0046] Figure 1 shows carbon nanofibers 4 used to form a conductive composite 1 according to the invention. Figure 1a) shows pristine carbon nanofibers 4. The carbon nanofibers 4 preferably have a diameter of 15 pm, an electrical conductivity of 170 S / cm and / or a specific surface area of ​​120 m². 2 / g. Instead of carbon nanofibers 4, all conventional carbon-based fibers can be used. However, the corresponding fibers must have pores.

[0047] 2.

[0048] In a first step for the production of the conductive composite 1 according to the invention, a lithiophilic material 3 is deposited on the surface of the corresponding fibers. All conventional deposition methods can be used for this purpose, particularly the one shown in the figure.

[0049] 3. Chemical vapor deposition, also known as CVD.

[0050] Figure 1b) shows such a carbon nanofiber 4 whose surface is completely covered with lithiophilic material 3. The lithiophilic material 3 is deposited not only on the outer shell 5 of the carbon nanofiber 4, but also on the surface within the pores 2.

[0051] Subsequently, the lithiophilic material 3 is removed from the outer shell 5 of the respective fiber. Figure 1c) shows such a fiber. The partial removal of the lithiophilic material 3 from the outer shell 5 of the fibers is particularly preferably carried out by means of an etching process as shown in Figure 4. Etching makes it particularly reliable to remove the lithiophilic material 3 from the outer shell 5 of the carbon nanofibers 4 and to leave it on the surface within the pores 2.

[0052] Figure 1 shows only a single fiber of the conductive composite 1. A multitude of these fibers can be present, for example, in the form of a powder or granules. This powder or granules can be pressed into more or less stable or solid layers. Electrodes or current collectors for solid-state batteries can be manufactured from such layers. Other manufacturing processes besides pressing are also possible. Figure 11 shows a single fiber of the conductive composite 1 according to the invention in a current collector or an electrode of such a solid-state battery after a charging process. As Figure 11 shows, the so-called lithium plating, or the formation of solid lithium Li, takes place exclusively within the pores 2 of the respective fiber. This results from the fact that the lithiophilic material 3 is arranged exclusively on the surface of the carbon nanofibers 4 within the pores 2.A solid-state battery comprising electrodes which in turn have the conductive composite 1 according to the invention is characterized by outstanding properties. Since the lithium plating is limited exclusively to the area within the pores 2, the increase or decrease in volume during charging and discharging can be reduced to a minimum. In addition, the gravimetric energy density and volumetric energy density can be improved. The corresponding solid-state battery can also be manufactured cost-effectively.

[0053] Figure 2 shows, in subfigures a) and b), two electrodes or current collectors with a layered structure. In each case, a layer 201 of corresponding carbon-based fibers, preferably carbon nanofibers 4, is arranged between a copper foil 202 and a nickel foil 203. In Figure 2a), the carbon nanofibers 4 are in their natural state or pristine condition. In Figure 2b), however, the conductive composite 1 is shown, i.e., corresponding carbon nanofibers 4 coated with the lithiophilic material 3, wherein the deposition of the lithiophilic material 3 is limited exclusively to the surface area within the pores 2. Zinc is particularly preferably used as the lithiophilic material 3. Figure 2 shows the respective current collectors after lithium plating.As can be seen in Figure 2, the current collector in Figure 2b) is characterized by a significantly lower increase in thickness compared to the current collector shown in Figure 2a).

[0054] Figure 3 illustrates a specific embodiment for coating carbon nanofibers 4 with zinc by chemical vapor deposition. Specifically, hollow or porous carbon nanofibers 4 with a fiber diameter of 15 pm, an electrical conductivity of 170 S / cm, and a specific surface area of ​​120 m² are described. 2 / g is used as the base material for the anode current collector of a solid-state battery. The carbon nanofibers 4 are positioned in powder form on a powder holder 6 in a CVD chamber 7. An inert atmosphere is created in the CVD chamber 7. This inert atmosphere is heated to a specific temperature. A diethylzinc solution in toluene with a concentration of 1.5 M is evaporated as a liquid precursor for zinc deposition using a bubbler 9 with a nitrogen gas flow rate of 100 sccm at a pressure of 1 Torr for one hour. This evaporated precursor is introduced into an aluminum oxide tube 8, which is heated to a temperature above 450°C. Subsequently, the zinc catalyst is deposited onto the carbon nanofibers 4 according to a specific chemical equation. The chemical equation is:

[0055] Zn(C2H5)2-> Zn + C2H6+ C2H4

[0056] Figure 3 shows, in addition to the bubbler 9, two heating elements 10 for heating the aluminium oxide tube 8.

[0057] Figure 4 illustrates the process for the partial removal of the lithiophilic material 3 from the carbon nanofibers 4. 100 ml of sodium hydroxide (NaOH) with a concentration of 1 M at a temperature of 80°C is used as the etchant for a 0.5 g sample of the carbon nanofibers 4. The etchant is prepared in step 401. To remove the lithiophilic material 3, preferably the zinc catalyst, from the outer surface of the carbon nanofibers 4, a vacuum pump is used to draw the etchant through the sample of carbon nanofibers 4 coated with the lithiophilic material 3 within a time interval of 1.5 seconds. For this purpose, in step 402, the etchant is placed together with the sample into a suitable container. In step 403, the etchant is drawn through the sample using the vacuum pump. The sample is then washed at least once with deionized water.In step 404, the sample is rinsed with deionized water, preferably three times. The rinsed sample is then stirred in a container full of deionized water. This is shown in step 405. Preferably, the stirring is carried out at a rotational speed of 200 rpm for 10 minutes. Subsequently, in step 406, a drying process is carried out at 80°C for two hours. Optionally, steps 404 to 406 can be repeated at least a second time, as indicated by step 407. The conductive composite 1 is obtained as a result. The lithiophilic material 3 is located on the surface of the fibers within the pores 2, but not on the remaining surface. Figure 5 illustrates a process for producing a half-cell comprising an electrode or current collector, containing the conductive composite 1 according to the invention.The following work steps must be carried out in a pure argon atmosphere, which is characterized by an extremely low water content, in particular less than 0.1 ppm.

[0058] Three cell body parts are prepared, as shown in step 501. In step 502, the lower and middle parts are joined, and 0.15 g of solid electrolyte is introduced into the central bore. The upper cell body part is then placed on top and tightened to compress the solid electrolyte. This is shown in step 503. The cell body parts are then pressed together for 10 seconds at a pressure of 10 MPa, as shown in step 504. The part that will later form the negative terminal is then opened, and 0.08 g of lithium is introduced into the middle cell body part. Preferably, this is a Li-In powder. This is done in step 505. Subsequently, in step 506, the powder is covered with a nickel foil. The cell body is closed and then pressed for three minutes at a pressure of 60 MPa in step 507.Now, the opposite side of the cell body, which will later form the positive electrode, is opened and 0.015 g of the conductive composite 1 sample is inserted. This is done in step 508. In step 509, the sample is also covered with a nickel foil. Finally, in step 510, the entire cell body is inserted into a suitable cell press and compressed. Preferably, the press is tightened with a torque of 70 Nm.

[0059] For the half-cell thus produced, the conductive composite 1 according to the invention is used as the cathode material, i.e., to form the working electrode. The aforementioned In-Li powder serves as the anode material, i.e., as the counter or reference electrode.

[0060] Figure 6 illustrates the process for manufacturing a complete cell. Here, three cell body parts are also prepared in step 601. In step 602, the central bore is filled with 0.15 g of the solid electrolyte. In step 603, the bore is closed and the top part of the cell body is rotated to distribute the solid electrolyte powder evenly. In step 604, a pressure of 10 MPa is applied to the cell body for 10 seconds. In step 605, the side of the cell body that will later represent the positive electrode is removed, and the cathode material is added according to a target NP ratio. The removed cell body part is reinserted and tightened in step 606. In step 607, a pressure of 40 MPa is applied for three minutes. Now, the opposite side of the cell body is opened, and another sample of 0.015 g of the conductive composite 1 is added to the opening. This is done in step 608.In step 609, the filled opening is closed and the corresponding cell body part is rotated to flatten the sample. In step 610, a nickel foil is placed onto the compressed conductive composite 1. In step 611, the assembled cell body is reinserted into a cell press and compressed with a torque of preferably 70 Nm. In this case, the cathode is made of LiNbOa (LNO) coated with NCM811. The anode comprises, or is formed by, the current collector containing the conductive composite 1.

[0061] Figures 7 and 8 illustrate the advantages of using the conductive composite 1 according to the invention for forming electrodes or current collectors of solid-state batteries. Figure 7 shows various diagrams. Subfigures 7a) to c) show the initial voltage profiles of corresponding cells. Subfigures d) to f) show the discharge capacity of the respective cells over several charge and discharge cycles. Figures 7a) and d) were measured on a cell whose current collector contains a layer of untreated or pristine carbon nanofibers 4. Figures 7b) and e) were measured on a cell whose current collector comprises carbon nanofibers 4 coated with the lithiophilic material 3 both within the pores 2 and on the outer shell 5.Figures 7c) and f) were measured on a cell whose current collector comprises the conductive composite 1 according to the invention, i.e. carbon nanofibers 4 which are provided with the lithiophilic material 3 exclusively within the pores 2.

[0062] The conductive composite 1 according to the invention, i.e., the material in which the lithiophilic catalyst is deposited exclusively within the pores 2 of the carbon nanofibers 4, exhibits remarkable advantages in both initial discharge capacity and efficiency. The discharge capacity profile across the various discharge cycles underscores the superior performance of the conductive composite 1 according to the invention for forming electrodes or current collectors for solid-state batteries. For example, a corresponding cell exhibits the highest capacity retention rate during the seventh cycle. Figure 8 illustrates the results in tabular form. The table shows the results for untreated carbon nanofibers 4 in the first row, for carbon nanofibers 4 fully coated with the lithiophilic material 3 in the second row, and the third row...

[0063] Line for the conductive composite according to the invention 1.

Claims

Patent claims 1. Conductive composite (1) comprising an electrically conductive material having pores (2). Carrier material which is at least partially provided within the pores (2) with a lithiophilic material (3), characterized in that the carrier material is formed by carbon-based fibers.

2. Conductive composite (1) according to claim 1, characterized in that the lithiophilic material (3) is arranged exclusively within the pores (2) of the carbon-based fibers.

3. Conductive composite (1) according to claim 1 or 2, characterized in that the carbon-based fibers are formed by carbon nanofibers (4).

4. Conductive composite (1) according to claim 3, characterized in that the carbon nanofibers (4) have a diameter of 15 pm, an electrical conductivity of 170 S / cm and / or a specific surface area of ​​120 m² 2 exhibit / g.

5. Conductive composite (1) according to one of claims 1 to 4, characterized in that the lithiophilic material (3) is formed by a metal or semimetal which is configured to form an alloy or compound with lithium.

6. Conductive composite (1) according to claim 5, characterized in that the lithiophilic material (3) is formed by at least one of the following substances: gold, platinum, palladium, silicon, silver, aluminium, bismuth, tin and / or zinc.

7. Method for producing a conductive composite (1) according to one of claims 1 to 6, characterized by the following process steps: - Deposition of the lithiophilic material (3) on the surface of the carbon-based fibers, such that the lithiophilic material (3) is deposited on the carbon-based fibers both within the pores (2) and on the outer shell (5) of the fibers; and - selective removal of the lithiophilic material (3) from the outer shell (5) of the carbon-based fibers, leaving the lithiophilic material (3) on the surface within the pores (2).

8. Method according to claim 7, characterized in that the lithiophilic material (3) is deposited on the surface of the carbon-based fibers by means of chemical vapor deposition.

9. Method according to claim 7 or 8, characterized in that the lithiophilic material (3) is selectively removed from the outer shell (5) of the carbon-based fibers by etching.

10. Solid-state battery comprising a first electrode containing at least some lithium, a second electrode and a solid electrolyte arranged between the first and second electrodes, characterized in that the second electrode comprises a conductive composite (1) according to any one of claims 1 to 6.

11. Solid-state accumulator according to claim 10, characterized in that the first electrode is designed as an anode and the second electrode is designed as a cathode.

12. Solid-state accumulator according to claim 10 or 11, characterized in that the pores (2) of the carbon-based fibers are free of lithium in a discharged state of the accumulator.

13. Solid-state accumulator according to claim 10 or 12, wherein the first electrode is configured as a cathode, characterized in that the active material of the first electrode has the following chemical equation: LiaNibCocMdC , wherein M is selected from the group consisting of: manganese, aluminum, magnesium and zirconium, and wherein the following ratios are maintained: 0.8 < a < 1.2; 0.8 < b < 1.0; 0.0 < c < 0.2; and 0.0 < d < 0.

2.

14. Solid-state accumulator according to one of claims 10 to 13, characterized in that the solid electrolyte is selected from a group consisting of: sulfide-based electrolytes, oxide-based electrolytes and halide-based electrolytes.

15. Battery comprising at least two individual cells, characterized in that the individual cells are each formed by a solid-state accumulator according to one of claims 10 to 14.

16. Vehicle, identified by a battery according to claim 15, in particular for operating an electric Drive unit.

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