Thermally conductive filler for cables and method for its preparation

Abstract

The application discloses a heat-conducting filler for cables and a preparation method thereof, and belongs to the technical field of materials. According to the preparation method, MXenes material is first subjected to aggregation and alkalization treatment under the action of lye to form modified nanosheet MXenes material with a special structure, then after freeze-drying and annealing treatment, directional conversion of functional groups in the material occurs, and a three-dimensional porous structure is finally formed, so that the finally obtained product has a large heat dissipation area and an efficient heat transfer path, and has excellent heat dissipation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to a heat-conducting filler for cables and a preparation method thereof. Background Art

[0002] Conductive cables are widely used in the current new energy sector. As new energy technologies evolve, higher demands are placed on the heat dissipation performance of conductive cables. Currently, most conductive cables use thermally conductive fillers composed of micron- or nanometer-sized ceramic powders such as aluminum oxide, aluminum nitride, and silicon nitride. However, due to the upper limit on filler loading in conductive cables, the heat dissipation performance of these ceramic powders cannot be fully utilized. Furthermore, introducing high levels of thermally conductive fillers into conductive cables can severely impair the product's mechanical and electrical properties, and even stability.

[0003] MXenes are a new type of two-dimensional nanomaterial, typically prepared by etching. Composed of transition metal carbides, nitrides, or carbonitrides a few atomic layers thick, they possess high specific surface area, high thermal conductivity, and superior mechanical properties. Currently, they are primarily used in energy storage and, in theory, are well-suited to replacing traditional ceramic powders as heat-dissipating fillers for cables. However, in practical applications, MXenes suffer from heavy stacking between nanosheets or the formation of self-supporting structures, resulting in low specific surface area or poor dispersion, making them incapable of achieving good thermal conductivity. Furthermore, MXenes prepared by etching exhibit poor thermal conductivity due to structural and compositional defects, making it difficult to achieve the same heat dissipation levels as traditional ceramic powders. Summary of the Invention

[0004] Based on the defects of the existing technology, the purpose of the present invention is to provide a method for preparing thermally conductive fillers for cables. First, the MXenes material is precipitated and alkalized under the action of alkaline solution to form a modified nanosheet MXenes material with a special structure. Subsequently, after freeze-drying and annealing, the functional groups in the material undergo directionally transformed, and a three-dimensional porous structure is finally formed. The final product has a large heat dissipation area and an efficient heat transfer path, and has an excellent heat dissipation effect.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing a thermally conductive filler for a cable comprises the following steps:

[0007] (1) Etching, cleaning, ultrasonically dispersing, and centrifuging the precursor material to obtain a MXenes material suspension;

[0008] (2) adding an alkaline solution to the MXenes suspension and stirring until flocculent precipitation occurs, allowing the mixture to stand, separating the solid, washing, and freeze-drying to obtain a modified MXenes material; the concentration of the alkaline solution is ≥5 mol / L;

[0009] (3) The modified MXenes material is annealed to obtain the thermal conductive filler for the cable.

[0010] The difference between the thermally conductive filler for cables described in the present invention and the preparation method of traditional MXenes materials is that the MXenes material is prepared in advance and then an alkaline solution is introduced for stirring and standing treatment. During this process, the cations in the alkaline solution will cause the nanosheet structure in the MXenes material to rapidly aggregate and precipitate through electrostatic action, while forming a special three-dimensional porous structure, which greatly increases the heat dissipation area of ​​the resulting product and optimizes the heat transfer path. At the same time, hydroxide ions will undergo functional group substitution on the surface of the MXenes material. After freeze-drying and annealing treatment, the hydroxide ions on the surface of the material will be converted into oxygen-containing groups, which greatly increases the phonon scattering probability of the material, and the thermal conductivity of the thermally conductive filler for cables finally prepared is significantly improved.

[0011] If the alkaline solution is not modified during the product preparation process, or the concentration of the alkaline solution is low and the degree of modification is low, the heat dissipation of the product may not be improved. On the other hand, if annealing is not performed after alkaline solution treatment, there will be a large number of hydroxide ions on the surface of the product, which cannot be converted into oxygen-containing groups with a gain effect. Instead, the thermal conductivity of the product will deteriorate. All processing steps at each stage are indispensable.

[0012] Preferably, the precursor material is at least one of Ti3AlC2, Ti2AlC, V4AlC3, and V2AlC.

[0013] Preferably, the etching treatment in step (1) is performed by soaking the precursor material in an etching solution, and the etching solution includes hydrochloric acid and lithium fluoride;

[0014] More preferably, during the soaking, the etching solution is stirred at 40-50° C. for 45-50 hours until bubbles no longer form.

[0015] More preferably, the etching solution is a mixture of hydrochloric acid and lithium fluoride, the mass concentration of the hydrochloric acid is 35-40%, and the ratio of the volume of the hydrochloric acid to the mass of the lithium fluoride is (20-30) mL:1 g.

[0016] The MXenes material prepared by the etching method has a low degree of re-stacking and self-support in its lamellar structure, but its own heat dissipation is poor. The method described in the present invention further gives the MXenes material obtained by the etching method a material structure and surface functional groups with high heat dissipation through alkali immersion coagulation, freeze drying and annealing processes, and the material obtained by the above-mentioned preferred etching process has a better effect of further modification.

[0017] Preferably, in step (2), the concentration of the MXenes material suspension is 5-8 g / L.

[0018] Preferably, the alkaline solution is at least one of a sodium hydroxide solution and a potassium hydroxide solution.

[0019] More preferably, the concentration of the alkaline solution is 6-9 mol / L.

[0020] More preferably, the volume ratio of the MXenes material suspension to the alkaline solution is (0.8~1.2):(0.8~1.2).

[0021] When a low-concentration alkaline solution is used to modify MXenes materials, it not only fails to optimize the structure and surface functional groups of the MXenes materials, but may even destroy the structure of the MXenes materials to a certain extent due to oxidation. However, when a high-concentration alkaline solution within the above preferred range is selected for modification, since the dissolved oxygen content in the solution itself is low and it will passivate the MXenes materials, it can optimize the structure and functional groups while ensuring that the structure is not damaged.

[0022] Preferably, in step (2), the standing time is 8 to 12 hours.

[0023] After the flocculent precipitate is formed, the resulting material is further placed in an alkaline solution for alkalinization treatment. The fluorine groups on the surface of the MXenes material are replaced by hydroxide groups. At the same time, the structure of the MXenes material will not be destroyed during the process, and a three-dimensional porous structure is gradually formed.

[0024] Preferably, the annealing treatment in step (3) is performed under an inert atmosphere.

[0025] More preferably, the temperature during the annealing treatment is 300-400° C., and the time is 8-12 hours.

[0026] The annealing process under the above-mentioned preferred conditions can more effectively convert the -F groups and -OH groups on the surface of the original MXenes material into -O groups, thereby improving the thermal conductivity of the product. At the same time, the material structure is more dispersed and the overall heat dissipation effect is better.

[0027] Another object of the present invention is to provide a thermally conductive filler for a cable prepared by the method for preparing the thermally conductive filler for a cable.

[0028] Another object of the present invention is to provide a conductive cable, comprising the thermally conductive filler for the cable of the present invention.

[0029] Preferably, the conductive cable includes a photovoltaic cable or an EV charging cable.

[0030] The thermally conductive filler for cables described in the present invention has ideal heat dissipation performance due to its special three-dimensional porous structure and the arrangement of surface functional groups. After a sample containing this product is continuously heated at 180°C for 1 hour, the temperature of the sample can be maintained below 70°C, with excellent heat dissipation effect. At the same time, it is essentially a modified MXenes material with a specific gravity much lower than traditional ceramic powder. Therefore, it is very suitable for various types of conductive cables that have high requirements for heat dissipation performance but the filler filling amount cannot be too high.

[0031] The beneficial effect of the present invention is that the present invention provides a method for preparing a thermally conductive filler for a cable. First, the MXenes material is precipitated and alkalized under the action of an alkaline solution to form a modified nanosheet MXenes material with a special structure. Subsequently, after freeze-drying and annealing, the functional groups in the material undergo a directionally transformed, and a three-dimensional porous structure is finally formed. The final product has a large heat dissipation area and an efficient heat transfer path, and has an excellent heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a photo of the suspension prepared by the preparation method described in Example 1 of the present invention;

[0033] Figure 2 The real-time temperature diagram of the product obtained in Example 1 of the present invention during the heating test, wherein the left figure a is the test result diagram at a heating setting temperature of 90°C, and the right figure b is the test result diagram at a heating setting temperature of 180°C;

[0034] Figure 3 The real-time temperature diagram of the product obtained in Comparative Example 1 of the present invention during the heating test, wherein the left figure a is the test result diagram when the heating temperature is set to 90°C, and the right figure b is the test result diagram when the heating temperature is set to 180°C;

[0035] Figure 4 The real-time temperature diagram of the product obtained in Comparative Example 2 of the present invention during the heating test, wherein the left figure a is the test result diagram when the heating temperature is set to 90°C, and the right figure b is the test result diagram when the heating temperature is set to 180°C;

[0036] Figure 5The real-time temperature diagram of the product obtained in Comparative Example 3 of the present invention during the heating test, wherein the left figure a is the test result diagram when the heating temperature is set to 90°C, and the right figure b is the test result diagram when the heating temperature is set to 180°C;

[0037] Figure 6 The real-time temperature diagram of the product obtained in Comparative Example 4 of the present invention during the heating test, wherein the left figure a is the test result diagram when the heating temperature is set to 90°C, and the right figure b is the test result diagram when the heating temperature is set to 180°C;

[0038] Figure 7 This is a physical picture of the product obtained in Example 1 of the present invention;

[0039] Figure 8 The figures are physical pictures of the products obtained in the comparative examples of the present invention, wherein the upper left figure a is a physical picture of the product obtained in comparative example 1, the upper right figure b is a physical picture of the product obtained in comparative example 2, the lower left figure c is a physical picture of the product obtained in comparative example 3, and the lower right figure d is a physical picture of the product obtained in comparative example 4;

[0040] Figure 9 This is a scanning electron microscope image of the product obtained in Example 1 of the present invention;

[0041] Figure 10 These are scanning electron microscope images of the products obtained in each comparative example of the present invention, wherein the upper left figure a is a scanning electron microscope image of the product obtained in comparative example 1, the upper right figure b is a scanning electron microscope image of the product obtained in comparative example 2, the lower left figure c is a scanning electron microscope image of the product obtained in comparative example 3, and the lower right figure d is a scanning electron microscope image of the product obtained in comparative example 4. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples. Its purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise all fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all conventional common reagents and instruments unless otherwise specified.

[0043] Example 1

[0044] An embodiment of a thermally conductive filler for a cable and a preparation method thereof according to the present invention comprises the following steps:

[0045] (1) 2 g of the precursor material Ti3AlC2 was placed in an etching solution obtained by mixing 50 mL of 36% mass concentration hydrochloric acid and 2 g of lithium fluoride for etching until no bubbles were generated in the mixture. The mixture was then stirred at 150 rpm at 45 °C for 48 h. The solid was filtered and washed with deionized water. 200 mL of deionized water was ultrasonically dispersed for 1 h. The suspension was then collected by centrifugation at 2000 rpm to obtain a MXenes material suspension. The suspension was irradiated with light, as shown in FIG. Figure 1 As shown, it can be seen that the suspension has Tyndall effect and the material has good suspension properties;

[0046] (2) Take 50 mL of the MXenes material suspension separately, add 50 mL of 6 mol / L potassium hydroxide solution into it and stir until flocculent precipitation appears. Let it stand for 10 hours for alkalization treatment, separate the solid, wash with deionized water, and freeze-dry at -55 ° C and -0.06 MPa for 24 hours to obtain the modified MXenes material;

[0047] (3) The modified MXenes material is annealed at 400° C. for 12 h in an argon atmosphere to obtain the thermal conductive filler for the cable.

[0048] Example 2

[0049] The embodiment of a thermally conductive filler for a cable and a preparation method thereof according to the present invention differs from Example 1 only in that the precursor material Ti3AlC2 is replaced by Ti2AlC.

[0050] Example 3

[0051] The embodiment of a thermally conductive filler for a cable and a preparation method thereof according to the present invention differs from Example 1 only in that the precursor material Ti3AlC2 is replaced by V2AlC.

[0052] Example 4

[0053] The embodiment of the thermal conductive filler for cables and the preparation method thereof according to the present invention is different from Example 1 only in that the concentration of the potassium hydroxide solution is 7.5 mol / L.

[0054] Example 5

[0055] The embodiment of the thermal conductive filler for cables and the preparation method thereof according to the present invention is different from Example 1 only in that the concentration of the potassium hydroxide solution is 9 mol / L.

[0056] Comparative Example 1

[0057] A thermally conductive filler for a cable and a preparation method thereof, which differs from Example 1 only in that the preparation method of the thermally conductive filler for a cable comprises the following steps:

[0058] 2g precursor material Ti3AlC2 was placed into an etching solution prepared by mixing 50 mL of 36% mass concentration hydrochloric acid and 2g lithium fluoride, and etching was performed until no bubbles were generated in the resulting mixture. Subsequently, stirring was performed at 150 rpm at 45°C for 48 h, the solid was filtered, and then washed with deionized water, 200 mL of deionized water was ultrasonically dispersed for 1 h, and then collected by centrifugation at a rate of 2000 rpm to obtain a MXenes material suspension, and freeze-drying was performed at -55°C and -0.06 MPa for 24 h to obtain the heat-conducting filler for cables.

[0059] Comparative Example 2

[0060] A heat-conducting filler for cables and a preparation method thereof, which differ from those of Example 1 only in that the preparation method of the heat-conducting filler for cables comprises the following steps:

[0061] (1) 2g precursor material Ti3AlC2 was placed into an etching solution prepared by mixing 50 mL of 36% mass concentration hydrochloric acid and 2g lithium fluoride, and etching was performed until no bubbles were generated in the resulting mixture. Subsequently, stirring was performed at 150 rpm at 45°C for 48 h, the solid was filtered, and then washed with deionized water, 200 mL of deionized water was ultrasonically dispersed for 1 h, and then collected by centrifugation at a rate of 2000 rpm to obtain a MXenes material suspension, and freeze-drying was performed at -55°C and -0.06 MPa for 24 h to obtain a modified MXenes material.

[0062] (2) The modified MXenes material was annealed at 400°C for 12 h under an argon atmosphere to obtain the heat-conducting filler for cables.

[0063] Comparative Example 3

[0064] A heat-conducting filler for cables and a preparation method thereof, which differ from those of Example 1 only in that the preparation method of the heat-conducting filler for cables comprises the following steps:

[0065] 2 g of the precursor material Ti3AlC2 was placed in an etching solution obtained by mixing 50 mL of 36% mass concentration hydrochloric acid and 2 g of lithium fluoride for etching until no bubbles were generated in the obtained mixture. The mixture was then stirred at 45°C at a speed of 150 rpm for 48 hours, the solid was filtered, and then washed with deionized water. 200 mL of deionized water was ultrasonically dispersed for 1 hour, and then centrifuged at 2000 rpm to obtain a MXenes material suspension. Subsequently, 50 mL of the MXenes material suspension was taken separately, 50 mL of a 6 mol / L potassium hydroxide solution was added thereto, and the mixture was stirred until a flocculent precipitate appeared. The mixture was allowed to stand for 10 hours for alkalization treatment, the solid was separated, washed with deionized water, and freeze-dried at -55°C and -0.06 MPa for 24 hours to obtain the thermal conductive filler for the cable.

[0066] Comparative Example 4

[0067] A thermally conductive filler for a cable and a preparation method thereof, the difference from Example 1 being that the concentration of the potassium hydroxide solution is 3 mol / L.

[0068] Effect Example 1

[0069] In order to verify the use effect of the thermal conductive filler for cable of the present invention, the thermal conductive filler for cable of each embodiment and comparative example was processed into a test sample. The processing method was as follows: 30 mg of the thermal conductive filler was taken, cold pressed into a sheet using a tablet press, and trimmed into 3×3 cm 2 The test was carried out on a square specimen with a compression load of 5 MPa and a loading time of 5 min.

[0070] The samples were then heated in an oven at 90°C and 180°C for 1 hour. The real-time temperature of the samples was recorded every 5 minutes. The maximum real-time temperature of the samples in each period was finally recorded and statistically analyzed. The results are shown in Table 1.

[0071] Table 1

[0072]

[0073] From the results, it can be seen that the thermally conductive filler for cables of the present invention has ideal thermal conductivity. After heating at 90°C for 1 hour, the test sample can basically maintain a temperature of about 40°C, and after heating at 180°C for 1 hour, it can basically maintain a temperature of about 60°C.

[0074] In contrast, the thermal conductivity of the comparative examples is not ideal. Whether heated at 90°C or 180°C, the maximum real-time temperature thereof is significantly lower than that of the examples.

[0075] The statistical data of the test samples of Example 1 and Comparative Examples 1 to 4 were summarized, and the results are as follows:Figures 2-6 As shown, it can be seen that when the heating program is set at 90°C, since the heating temperature is close to the real-time temperature of the sample, the thermal conductive filler has an obvious heat dissipation effect, so the real-time temperature of the environment fluctuates to a certain extent in different time periods, but the real-time temperature of the sample is basically stable, indicating that the thermal conductive filler in each sample begins to dissipate heat at the initial stage of heating and the heat dissipation rate is relatively stable. At 180°C, both the ambient temperature and the real-time temperature of the sample are relatively stable. The real-time temperature of the samples processed with the comparative thermal conductive filler is much higher than that of the sample obtained in Example 1.

[0076] The products obtained from Example 1 and Comparative Examples 1 to 4 were observed, and the results were as follows: Figure 7 and 8 As shown, it can be seen that the thermal conductive filler for cable obtained in Example 1 has high looseness and is in a highly dispersed powder state, while the MXenes material in the product of Comparative Example 1, which has not been treated with alkaline solution for modification and annealing, showed obvious agglomeration during freeze-drying, and the product was in block form. Even subsequent crushing and grinding could not optimize the microscopic agglomerated self-supporting structure, so the thermal conductivity of the product was low; the product of Comparative Example 2 was annealed on the basis of Comparative Example 1, but the morphology was not significantly different from that of the product of Comparative Example 1, indicating that alkaline solution treatment is the key to product structure optimization; the product of Comparative Example 3 was treated with alkaline solution, so it has good dispersibility; although the product of Comparative Example 4 was modified and annealed with alkaline solution, it still had a block morphology. The main reason is that the low concentration of alkaline solution not only cannot optimize the structure of the MXenes material, but also converts part of the Ti in the material into TiO2 due to the oxidation reaction, thereby destroying the material structure. A self-supporting structure appeared in the product, and white TiO2 particles existed on the surface.

[0077] Furthermore, the products obtained in Example 1 and Comparative Examples 1 to 4 were observed using a scanning electron microscope. The results are as follows: Figure 9 and 10As shown, it can be seen that at the microscopic scale, the product obtained in Example 1 has an ideal three-dimensional porous structure, which is attributed to the treatment step of coagulation modification of the MXenes material in an alkaline solution, while the product obtained in Comparative Example 1 also has a three-dimensional porous structure, but the three-dimensionality is slightly weaker. The main reason is that the product in Comparative Example 1 is freeze-dried during preparation. During this process, water molecules form ice crystal templates, thereby giving the product a certain three-dimensional porous structure; similarly, the product in Comparative Example 2 is also freeze-dried, so its morphology is similar to that of Comparative Example 1; the product in Comparative Example 3 is not annealed compared to the product in Example 1, and is similar to the product in Example 1 from the microscopic morphology, indicating that the annealing treatment is mainly for regulating the surface functional groups of the product, while the regulation range of the morphology structure is small; although the product in Comparative Example 4 also presents a certain three-dimensional porous structure, the three-dimensional sense is low, the spacing between the nanosheet layers is small, and a small amount of white particles appear on the surface of the nanosheet layer, which corresponds to the actual picture.

[0078] In order to further study the effects of alkaline solution treatment and annealing treatment on the chemical composition of the products in the product preparation method of the present invention, the products of Example 1 and Comparative Examples 1 to 4 were subjected to elemental content analysis and XPS analysis (peak fitting to confirm the functional group distribution, where the larger the relative area, the greater the proportion of functional group distribution on the product surface). The results are shown in Tables 2 and 3.

[0079] Table 2

[0080]

[0081] Table 3

[0082]

[0083] As can be seen from Table 2, the product of Comparative Example 1 was not subjected to alkaline solution modification and annealing treatment, while the product of Example 1 was subjected to the treatment. The relative contents of Ti and C elements of the two products are similar, but the relative amount of O element of the product of Example 1 is significantly increased, and the relative content of F element is significantly reduced, indicating that after the treatment, the fluorine-containing group is replaced by an oxygen-containing group, and the oxygen-containing group after further conversion has a significant gain in the heat dissipation performance of the product. The product of Comparative Example 2 was not subjected to alkaline solution treatment, but only to annealing treatment. The content of each element is close to that of the product of Comparative Example 1, and F element is still detected, indicating that only after the alkaline solution treatment is first performed, The functional groups in the product can be effectively regulated; the product of Comparative Example 3 was not annealed after the alkaline solution treatment. Although the relative contents of the O and F elements showed a certain trend of change, they were far less than those of the product of Example 1; the chemical composition of the product of Comparative Example 4 was quite different from that of the other products. The relative contents of the Ti and C elements were quite different from those of the product of Comparative Example 1, and the relative content of the F element was also reduced, indicating that the MXenes material underwent an obvious oxidation reaction during the low-concentration alkaline solubility treatment. The Ti element was oxidized into white TiO2 particles, and the nanosheet structure of the material was damaged, which is consistent with the test results above.

[0084] In Table 3, the product of Example 1 has fewer Ti-F bonds and Ti-OH bonds than the product of Comparative Example 1, and a higher content of Ti-O bonds. This is mainly because during the alkaline solution treatment, the -F group is replaced by -OH, and then -OH is converted to -O during the annealing treatment. This functional group can inhibit the vibration of Ti and C atoms, thereby inhibiting phonon scattering and improving the thermal conductivity of the product. The relative content of Ti-F bonds in the product of Comparative Example 2 did not change significantly compared to the product of Comparative Example 1, while the Ti-OH bonds and Ti-O bonds changed to a certain extent, indicating that annealing only converts a portion of Ti-OH bonds into Ti-O bonds. The relative content of Ti-F bonds in the product of Comparative Example 3 is low, but the content of Ti-O bonds is still low. Only the content of Ti-OH bonds increases, which does not significantly help improve the thermal conductivity of the product. The functional group bond distribution of the product of Comparative Example 4 is similar to that of Example 1, indicating that low-concentration alkaline solutions will also convert Ti-F bonds, but during the conversion process, the Ti element is oxidized into white TiO2 particles. Although it also contains Ti-O bonds, the material structure is damaged, so the thermal conductivity efficiency is poor.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the present invention.

Claims

1. A method for preparing a thermally conductive filler for a cable, characterized in that: The following steps are involved: (1) Etching, cleaning, ultrasonically dispersing, and centrifuging the precursor material to obtain a MXenes material suspension; (2) Adding alkaline solution to the MXenes suspension and stirring until flocculent precipitation occurs, standing, separating the solid, washing, and freeze-drying to obtain the modified MXenes material; The concentration of the alkaline solution is ≥5 mol / L; the alkaline solution is at least one of a sodium hydroxide solution and a potassium hydroxide solution; (3) Annealing the modified MXenes material to obtain the thermal conductive filler for the cable; the annealing is performed under an inert atmosphere at a temperature of 300-400° C. and for 8-12 hours.

2. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: The precursor material is at least one of Ti3AlC2, Ti2AlC, V4AlC3, and V2AlC.

3. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: The etching treatment in step (1) is performed by soaking the precursor material in an etching solution, wherein the etching solution includes hydrochloric acid and lithium fluoride.

4. The method for preparing a thermally conductive filler for a cable according to claim 3, wherein: The etching solution is a mixture of hydrochloric acid and lithium fluoride, the mass concentration of the hydrochloric acid is 35-40%, and the volume ratio of the hydrochloric acid to the mass ratio of the lithium fluoride is (20-30) mL:1 g.

5. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: In the step (1), the concentration of the MXenes material suspension is 5-8 g / L.

6. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: The concentration of the alkaline solution is 6-9 mol / L.

7. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: The volume ratio of the MXenes material suspension to the alkaline solution is (0.8~1.2): (0.8~1.2).

8. The method for preparing a thermally conductive filler for a cable according to claim 1, wherein: In the step (2), the standing time is 8 to 12 hours.

9. A thermally conductive filler for a cable prepared by the method for preparing a thermally conductive filler for a cable according to any one of claims 1 to 8.

10. A conductive cable, characterized in that: The thermally conductive filler for cables according to claim 9 is included.

11. The conductive cable according to claim 10, wherein: The conductive cable includes a photovoltaic cable or an EV charging cable.

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