An ionic battery composite material, a preparation method and application thereof

Abstract

The application discloses an ionic battery composite material and a preparation method and application thereof, and relates to the technical field of battery materials. The application wraps nano-flower tin disulfide with high-conductivity nano-boron carbide, and the obtained boron carbide-tin disulfide composite is wrapped in cut multi-walled carbon nanotubes, so that the interface impedance is reduced, more electronic transmission tunnels are provided, the boron carbide-tin disulfide composite can accommodate the volume change of the material itself in the ion deintercalation process, the serious volume expansion effect of tin disulfide as a negative electrode material in the charging and discharging process is overcome, and the damage of the electrode structure is prevented. The ionic battery composite material disclosed by the application is applied to the negative electrode of an ionic battery, can effectively improve the specific capacity and capacity retention rate of the battery, enhances the cycle stability of the battery work, and prolongs the service life of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to an ion battery composite material, its preparation method, and its application. Background Technology

[0002] Compared to lithium-ion batteries, potassium-ion batteries have become a new research hotspot in energy storage technology due to their simpler battery design, cheaper materials and manufacturing processes, and the greater abundance and lower cost of potassium resources. The principle of potassium-ion batteries is similar to that of lithium-ion batteries, using potassium ions instead of lithium ions for charge transfer. Electrode materials, as the core components of potassium-ion batteries, determine their performance, and the negative electrode material plays a crucial role in improving their performance.

[0003] Tin disulfide has advantages such as high specific capacity, low price and non-toxicity, and can be used to prepare negative electrode materials for ion batteries. However, tin disulfide has poor conductivity. When used as a composite material for potassium-ion batteries, it will have a severe volume expansion effect during frequent charge and discharge, which will lead to excessively rapid capacity decay and shortened cycle life of potassium-ion batteries.

[0004] The prior art discloses a multi-walled carbon nanotube confined tin disulfide material. This material has a carbon nanotube structure. As a good conductor of electrons, the multi-walled carbon nanotubes overcome the poor conductivity of tin disulfide and, to a certain extent, confine the volume expansion of tin disulfide during charge and discharge. However, its confinement effect is limited, the capacity retention rate of the material is still low, and the cycle stability is poor. After 50 cycles, the capacity retention rate is about 31.28%. Summary of the Invention

[0005] To overcome the shortcomings of existing tin disulfide as a negative electrode material, which suffers from severe volume expansion during charge and discharge, resulting in low battery capacity retention, this invention provides an ion battery composite material. By combining specific components and designing the structure of tin disulfide, the volume expansion effect of tin disulfide as a negative electrode material during charge and discharge is overcome, effectively solving the problems of rapid battery capacity depletion and poor cycle performance.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned ion battery composite material.

[0007] Another object of the present invention is to provide the application of the above-mentioned ion battery composite material in the preparation of ion battery anode.

[0008] Another object of the present invention is to provide a potassium-ion battery.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] An ion battery composite material, the ion battery composite material comprising a carbon support and a boron carbide-tin disulfide composite material encapsulated in the carbon support;

[0011] The carbon support is a diced multi-walled carbon nanotube;

[0012] The boron carbide-tin disulfide composite contains tin disulfide with a nanoflower-like structure, and boron carbide is wrapped around the surface of the nanoflower-like tin disulfide.

[0013] The boron carbide-tin disulfide composite contains 5-20% boron carbide by mass.

[0014] It should be noted that:

[0015] The boron carbide-tin disulfide composite of this invention contains 5-20% boron carbide by mass. Boron carbide has strong resistance to general corrosion and can provide good active areas for the battery. Coating a layer of boron carbide onto the surface of the nano-flower-like tin disulfide increases the degree of defects in the material, providing more active sites for ion storage and improving the conductivity of the material. The gaps in the nano-flower-like layered structure of tin disulfide can also increase the ion storage space. By controlling the content of both, excessive coating of the nano-flower-like tin disulfide with boron carbide can be avoided, which would reduce the ion storage space provided by the layered gaps of the nano-flower-like tin disulfide. However, the degree of defects increased by boron carbide is limited, while tin disulfide itself has poor conductivity and a severe volume expansion effect. Composite boron carbide with nano-flower-like tin disulfide alone cannot effectively reduce interfacial impedance, provide more electron transport tunnels, and has limited mitigation of the volume expansion effect.

[0016] Cleaving multi-walled carbon nanotubes (MWCNTs) involves cutting the sides of MCCNTs axially at a specific temperature. The resulting MCCNTs contain graphene obtained through this axial cutting, increasing the specific surface area and providing more active sites for the attachment of boron carbide-tin disulfide composites. The presence of cleaved MCCNTs improves the integrity and conductivity of the ion battery composite material. The provided active sites can also be used to store ions, such as potassium ions, in the battery. Furthermore, it increases electron transport tunnels, effectively mitigating volume expansion and thus improving the material's electrochemical performance. On the other hand, it facilitates the uniform dispersion of the boron carbide-tin disulfide composite, preventing stacking and ensuring sufficient contact between the composite material and the electrolyte. This shortens the electron or ion transport distance, enhances conductivity, and effectively mitigates volume expansion of the negative electrode material during charging and discharging, thereby preventing structural damage.

[0017] The integrity refers to the fact that the carbon support provides a growth framework for tin disulfide and boron carbide, and its own toughness can also provide space for the expansion effect of tin disulfide, making it less likely for the material structure to collapse.

[0018] This invention encapsulates nano-flower-shaped tin disulfide with boron carbide nanoparticles, resulting in a boron carbide-tin disulfide composite exhibiting a nano-flower-like structure. This composite is encapsulated within diced multi-walled carbon nanotubes, significantly reducing interfacial impedance while providing more ion storage space and electron transport tunnels. This enhances the material's conductivity and allows the ion battery composite to accommodate volume changes during ion (e.g., potassium ion) insertion / extraction processes, overcoming volume expansion effects, preventing electrode structure damage, thereby improving battery capacity retention, enhancing cycle stability, and extending battery life.

[0019] Furthermore, this invention combines boron carbide and nano-flower-like tin disulfide, and then encapsulates them in diced multi-walled carbon nanotubes. The resulting ion battery composite material not only has strong conductivity and excellent catalytic performance, but also improves the transmission performance and durability of rechargeable batteries.

[0020] Specifically, the multi-walled carbon nanotubes cut in this invention are oxidized multi-walled carbon nanotubes that have undergone acid oxidation treatment.

[0021] Oxidative dicing of multi-walled carbon nanotubes refers to cutting multi-walled carbon nanotubes along their axial direction by reaching a certain temperature and oxidation intensity under strong acid conditions. The surface of the diced multi-walled carbon nanotubes treated with acid oxidation will have more hydrophilic groups, which can effectively prevent metal agglomeration, provide more active sites, and further reduce the volume expansion effect.

[0022] As the walls of carbon nanotubes are gradually opened, the C-C bonds and carbon conjugated structures at the opened walls are gradually broken, and the graphitization of the de-chained multi-walled carbon nanotubes (MWCNTs) gradually weakens. The strong oxidative de-chaining process creates edge structures while also introducing vacancy defects (which are beneficial for the insertion and extraction of charging and discharging ions) and oxygen-containing groups (which increase hydrophilicity) into the carbon substrate structure.

[0023] Specifically, the boron carbide particles have a particle size of 40–80 nm.

[0024] The particle size of boron carbide affects the uniformity of the mixture of boron carbide and tin disulfide, the effective specific surface area of ​​the boron carbide-tin disulfide composite, and the synergistic effect between boron carbide and tin disulfide. To further enhance the synergistic effect between boron carbide and tin disulfide, the particle size of boron carbide was limited.

[0025] Preferably, the boron carbide particles have a particle size of 50–60 nm.

[0026] Specifically, the mass ratio of boron carbide, tin disulfide and carbon support is 1:(9-10):(13-15).

[0027] The mass ratio of boron carbide, tin disulfide, and carbon support affects the conductivity, ionic active sites, and expansion effect of ion battery composite materials. By controlling the mass ratio of the three, the specific capacity and cycle stability of the battery can be further improved.

[0028] Preferably, the boron carbide-tin disulfide composite contains 8-15% boron carbide by mass.

[0029] Specifically, the average length of the cut multi-walled carbon nanotubes is 10–30 μm, the average inner diameter is 5–10 nm, and the average outer diameter is 20–30 nm.

[0030] The length and inner and outer diameter of the multi-walled carbon nanotubes being cut affect the specific surface area, active site density, and vacancy defects of the carbon support. By controlling the range of these three factors, the conductivity of the composite material can be further improved, and more active sites can be provided.

[0031] This invention specifically protects a method for preparing the above-mentioned ion battery composite material, comprising the following steps:

[0032] The boron carbide-tin disulfide composite was obtained by thoroughly mixing nano-flower-like tin disulfide with boron carbide. Cut multi-walled carbon nanotubes were then added and thoroughly mixed to obtain an ion battery composite material.

[0033] Specifically, the nano-flower-shaped tin disulfide and boron carbide are mixed by wet ball milling, with the ball milling parameters being intermittent ball milling for 30-60 minutes and the ball milling time being 24-48 hours.

[0034] The 30-60 min intermittent ball milling refers to milling for 30-60 minutes and then stopping for 30-60 minutes.

[0035] Wet ball milling produces more uniform mixing, while dry ball milling is prone to accumulation; intermittent ball milling can avoid excessive temperature and prevent oxidation of the machine or materials.

[0036] Specifically, the boron carbide-tin disulfide composite is mixed with the cleaved multi-walled carbon nanotubes by wet ball milling, with the ball milling parameters being 30-60 min intermittent ball milling and a ball milling time of 24-48 h; more specifically, 30 min intermittent ball milling and a ball milling time of 24 h.

[0037] Because the particle size of the ion battery composite material is small, in order to avoid the loss of the ion battery composite material during filtration, vacuum filtration or centrifugation, the wet ball milling is followed by freeze drying, and the specific drying time is 48 to 72 hours.

[0038] Specifically, the preparation method of the nano-flower-like tin disulfide includes the following steps:

[0039] After the tin source and sulfur source are mixed evenly, they are fully reacted under heating conditions of 175-185℃. After cooling, they are soaked in water, and after solid-liquid separation, the solid is dried to obtain nano-flower-shaped tin disulfide.

[0040] The above-described preparation method of this invention can yield nano-flower-like tin disulfide. The reaction temperature affects the structure of the nano-flower-like tin disulfide. For example, it affects the thickness of the grains perpendicular to the crystal plane; a smaller thickness results in a smaller distance between the interior and surface of the crystal, which increases the electron transfer rate from the interior to the surface of the tin disulfide nanocrystal. Temperature also affects the density of active sites in the generated nano-flower-like tin disulfide; controlling the temperature can increase the density of active sites, which is more conducive to providing ionic active sites.

[0041] Specifically, the mass ratio of the tin source to the sulfur source is (1-1.2):(0.5-1).

[0042] Solid-liquid separation can be carried out by centrifugation. After centrifugation, the liquid is washed alternately with deionized water and ethanol, and then dried.

[0043] Specifically, the tin source is tin dichloride dihydrate, and the sulfur source is thiourea.

[0044] Specifically, the tin source and sulfur source are mixed by grinding, specifically grinding into a uniform grayish-white powder mixture, with a grinding time of not less than 30 minutes.

[0045] Specifically, the water used for soaking after cooling is deionized water, and the soaking time is 10 hours.

[0046] This invention particularly protects the application of the above-mentioned ion battery composite material in the preparation of ion battery anodes.

[0047] In the ion battery composite material of the present invention, the carbon support encapsulates the boron carbide-coated nano-flower-like tin disulfide sphere composite, which can improve the integrity and conductivity of tin disulfide and alleviate the volume expansion effect during charging and discharging. The ion battery anode prepared by this method has high specific capacity, high capacity retention rate and good cycle stability.

[0048] The present invention also protects a potassium-ion battery, wherein the negative electrode of the potassium-ion battery comprises the above-mentioned ion battery composite material.

[0049] The ion battery composite material described in this invention, when applied to the negative electrode of an ion battery, can effectively improve the specific capacity and capacity retention rate of the battery, enhance the cycle stability of the battery, and extend the battery's service life.

[0050] Specifically, the method for preparing the potassium-ion battery includes the following steps:

[0051] The above-mentioned ion battery composite material is mixed with acetylene black and binder to form a negative electrode material slurry. The negative electrode material slurry is coated on a copper foil substrate and dried to obtain an electrode sheet. The battery is assembled in an inert atmosphere, with potassium sheet as counter electrode, glass microfiber as separator, and KPF6 as electrolyte.

[0052] Among them, the counter electrode, the diaphragm, and the electrolyte are existing conventional equipment. The counter electrode is not limited to potassium sheets, the diaphragm is not limited to glass microfiber, and the electrolyte is not limited to KPF6.

[0053] Specifically, the adhesive is polyvinylidene fluoride (PVDF).

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] This invention provides a composite material for ion batteries. By encapsulating nano-flower-shaped tin disulfide with boron carbide nanoparticles, the resulting boron carbide-tin disulfide composite is encapsulated in diced multi-walled carbon nanotubes, which significantly reduces interfacial impedance, provides more ion storage space and electron transport tunnels, improves the conductivity of the material, and enables the boron carbide-tin disulfide composite to well accommodate the volume changes of the material itself during ion insertion and extraction. This overcomes the severe volume expansion effect that occurs when tin disulfide is used as a negative electrode material during charge and discharge, and prevents damage to the electrode structure.

[0056] The ion battery composite material described in this invention, when applied to the negative electrode of an ion battery, can effectively improve the specific capacity and capacity retention rate of the battery, enhance the cycle stability of the battery, and extend the battery's working life. The specific capacity is above 125 mAh / g, and the capacity retention rate can be maintained at more than 37% after 100 cycles. Attached Figure Description

[0057] Figure 1 This is a SEM image of the ion battery composite material from Example 1.

[0058] Figure 2 The image shows the XRD pattern of the ion battery composite material of Example 1.

[0059] Figure 3 The image shows a SEM image of the nanoflower-like tin disulfide prepared in Example 2.

[0060] Figure 4 The graph shows the cycle performance of the potassium-ion battery prepared from the ion battery composite material in Example 1.

[0061] Figure 5 An equivalent circuit diagram fitted to the AC impedance spectrum in electrochemical impedance spectroscopy. Detailed Implementation

[0062] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0063] Example 1

[0064] An ion battery composite material, the ion battery composite material comprising a carbon support and a boron carbide-tin disulfide composite;

[0065] The carbon support is an oxidatively cleaved multi-walled carbon nanotube;

[0066] The boron carbide-tin disulfide composite has a nanoflower-like structure;

[0067] The boron carbide-tin disulfide composite contains 9.42% boron carbide by mass.

[0068] The average particle size of the boron carbide particles is 50 nm.

[0069] The mass ratio of boron carbide, tin disulfide, and carbon support is 1:9.62:13.68;

[0070] The oxidized and cleaved multi-walled carbon nanotubes have a length of 20 μm, an inner diameter of 10 nm, and an outer diameter of 30 nm.

[0071] The above-mentioned oxidative cutting of multi-walled carbon nanotubes is obtained by conventional oxidative cutting of commercially available multi-walled carbon nanotubes.

[0072] Example 2

[0073] An ion battery composite material, with the same structure and composition as in Example 1, with differences shown in Table 1.

[0074] Table 1. Parameters of Ion Battery Composite Materials

[0075]

[0076]

[0077] Example 12

[0078] An ion battery composite material, with the same structure and composition as in Example 1, except that the oxidized and cleaved multi-walled carbon nanotubes have a length of 10 μm, an inner diameter of 5 nm, and an outer diameter of 20 nm.

[0079] Example 13

[0080] An ion battery composite material, with the same structure and composition as in Example 1, except that the oxidized and cleaved multi-walled carbon nanotubes have a length of 30 μm, an inner diameter of 10 nm, and an outer diameter of 30 nm.

[0081] Example 14

[0082] A method for preparing the ion battery composite material described in Example 1 includes the following steps:

[0083] 0.0625g of nano-flower-shaped tin disulfide and 0.0125g of boron carbide were placed in a ball mill containing deionized water and ball milled intermittently for 30 minutes. After 24 hours, the ball milling was continued for another 24 hours after oxidizing and cutting multi-walled carbon nanotubes to obtain the ion battery composite material.

[0084] The method for preparing the nano-flower-like tin disulfide is as follows:

[0085] 2.25g of tin dichloride dihydrate and 1.9g of thiourea were placed in an agate mortar, mixed evenly, and ground into a creamy white powder mixture for 30 minutes. The mixture was then placed in a 50mL corundum crucible without a lid and reacted in a forced-air drying oven at 180℃ for 2 hours. After cooling, the mixture was soaked in distilled water for 10 hours, and then washed repeatedly by centrifugation with deionized water and ethanol to separate and extract the solid. Finally, it was dried in air at 80℃ to obtain yellow nano-flower-like tin disulfide.

[0086] The preparation methods of the ion battery composite materials described in Examples 2 to 13 are the same as those in Example 14, except that the parameters of boron carbide, tin disulfide, and carbon support are adjusted according to those described in Examples 2 to 13.

[0087] Comparative Example 1

[0088] An ion battery composite material, with the same structure and composition as in Example 1, except that the oxidized and cleaved multi-walled carbon nanotubes are replaced with multi-walled carbon nanotubes.

[0089] The preparation method of the above-mentioned ion battery composite material is the same as that in Example 14, except that the oxidized and cleaved multi-walled carbon nanotubes are replaced with multi-walled carbon nanotubes.

[0090] Comparative Example 2

[0091] An ion battery composite material, with the same structure and composition as in Example 1, differs in that the tin disulfide content in the boron carbide-tin disulfide composite is 98% by mass.

[0092] The preparation method of the above-mentioned ion battery composite material is the same as that in Example 14, except that the amount of nano-flower-shaped tin disulfide used is different.

[0093] Result detection

[0094] The ion battery composite materials of the above embodiments and comparative examples were used to prepare potassium-ion batteries. The preparation method included the following steps:

[0095] The ion battery composite material, acetylene black, and PVDF binder were mixed in a ratio of 8:1:1 and ground evenly in an agate mortar. Then, N-methylpyrrolidone was added and stirred. The resulting slurry was coated on copper foil and dried at 60°C for 12 hours to obtain an electrode sheet. A button cell was assembled in an argon-filled glove box, using a potassium sheet as the counter electrode, glass microfiber as the separator, and KPF6 as the electrolyte. The assembled potassium-ion battery was then subjected to electrochemical performance testing.

[0096] Specific capacity test:

[0097] The potassium-ion batteries described above were tested using the LAND series battery testing system.

[0098] The specific capacity calculation formula is Cm=nZF / M, where n is the number of ions that a stoichiometric energy storage material can store in an energy storage reaction, Z is the number of electrons participating in the energy storage reaction, F is the Faraday constant 96485C / mol, and M is the relative molecular mass of the energy storage material (g / mol). Substituting the corresponding values, the specific capacity can be calculated.

[0099] The formula calculates that the unit of Cm is C / mol (coulomb / molar), which can be converted to mAh / g using the formula 3.6C (coulomb) = 1mAh (milliampere-hour).

[0100] Capacity retention test:

[0101] The battery is at 100 mA·g -1 The specific capacity of a potassium-ion battery after 10 or 100 cycles divided by the specific capacity of the first discharge cycle is the capacity retention rate after 100 cycles; the higher the capacity retention rate, the better the cycle stability.

[0102] Electrochemical impedance spectroscopy:

[0103] The electrochemical impedance spectroscopy of the battery was performed using a CHI600E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). All AC impedances were tested at 25°C, with a frequency of 10mHz to 100kHz and an AC voltage amplitude of 5mV.

[0104] Equivalent circuit for fitting AC impedance spectrum Figure 5 As shown.

[0105] The results are shown in Table 2.

[0106] Table 2. Electrical performance test results of potassium-ion batteries prepared from ion battery composite materials

[0107]

[0108] As shown in Table 2, the potassium-ion battery prepared from the composite material of the present invention exhibits a high specific capacity, exceeding 125 mAh / g, and maintains a capacity retention rate of over 37% after 100 cycles. This indicates that the present invention utilizes boron carbide nanoparticles to encapsulate nano-flower-like tin disulfide, and then further encapsulates the resulting boron carbide-tin disulfide composite within oxidized diced multi-walled carbon nanotubes. This overcomes the volume expansion effect of boron carbide, thereby improving the battery's specific capacity and capacity retention rate. The AC impedance does not exceed 212 Ω, indicating good conductivity. In Comparative Example 1, replacing the diced multi-walled carbon nanotubes with multi-walled carbon nanotubes resulted in a decrease in both the specific capacity and capacity retention rate of the resulting ion battery. This is because multi-walled carbon nanotubes cannot provide more active sites for the boron carbide-tin disulfide composite to attach, making it difficult to further alleviate the volume expansion effect. In Comparative Example 2, the excessively high tin disulfide content also led to a decrease in specific capacity and capacity retention rate. This is because the excessively high tin disulfide content prevents boron carbide from effectively encapsulating the tin disulfide, resulting in a more severe volume expansion effect.

[0109] Figure 1 The image shows a SEM image of the ion battery composite material from Example 1. As can be seen, tin disulfide grows in a lamellar pattern on cleaved carbon nanotubes, successfully mitigating the weakness of tin disulfide's conductivity. Simultaneously, the partially exposed cleaved carbon nanotubes indicate that the tin disulfide nanosheets exist in a moderate amount on the carbon matrix, allowing the cleaved carbon nanotubes to retain their function of storing ion electrons. In terms of the overall structure, it provides sufficient space for electrolyte permeation, shortens the ion transport path, and enhances ion adsorption capacity and electrochemical properties.

[0110] Figure 2 The XRD pattern of the ion battery composite material in Example 1 shows that the obtained ion battery composite material has characteristic peaks of 28.20°, 32.12°, and 49.96°, which correspond to the (100), (101), and (110) crystal planes of tin disulfide, respectively; and characteristic peaks of 24.50°, 35.96°, and 64.66°, which correspond to the (012), (104), and (105) crystal planes of boron carbide, respectively, indicating that the boron carbide-tin disulfide composite material was successfully prepared.

[0111] Figure 3 The image shows a SEM / TEM image of the nanoflower-like tin disulfide prepared in Example 2. As can be seen, the tin disulfide of the present invention exhibits a nanoflower-like structure, and its lamellar gaps can provide storage space for ions.

[0112] Figure 4The graph shows the cycle performance of the potassium-ion battery prepared from the ion battery composite material in Example 1. As can be seen from the graph, the potassium-ion battery still maintains 95.86% of its capacity retention after 500 cycles at a current density of 100 mA / g. No volume expansion effect of tin disulfide was observed, which proves that boron carbide coating of tin disulfide can alleviate the volume expansion effect of tin disulfide and improve the capacity retention and cycle performance of the battery.

[0113] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A composite material for ion batteries, characterized in that, The ion battery composite material includes a carbon support and a boron carbide-tin disulfide composite encapsulated in the carbon support. The carbon support is a cut multi-walled carbon nanotube obtained by cutting the side of the multi-walled carbon nanotube along the axial direction. The boron carbide-tin disulfide composite contains tin disulfide with a nanoflower-like structure, and boron carbide is wrapped around the surface of the nanoflower-like tin disulfide. The boron carbide-tin disulfide composite contains 5-20% boron carbide by mass.

2. The ion battery composite material as described in claim 1, characterized in that, The boron carbide particles have a particle size of 40–80 nm.

3. The ion battery composite material as described in claim 2, characterized in that, The boron carbide particles have a particle size of 50–60 nm.

4. The ion battery composite material as described in claim 1, characterized in that, The mass ratio of boron carbide, tin disulfide and carbon support is 1:(9-10):(13-15).

5. The ion battery composite material as described in claim 1, characterized in that, The average length of the cut multi-walled carbon nanotubes is 10–30 μm, the average inner diameter is 5–10 nm, and the average outer diameter is 20–30 nm.

6. The ion battery composite material as described in claim 1, characterized in that, The boron carbide The boron carbide content in the tin disulfide complex is 8-15% by mass.

7. A method for preparing the ion battery composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Boron carbide is obtained by thoroughly mixing nano-flower-like tin disulfide with boron carbide. Tin disulfide composites are added to cleaved multi-walled carbon nanotubes and then thoroughly mixed to obtain an ion battery composite material.

8. The preparation method according to claim 7, characterized in that, The preparation method of the nano-flower-like tin disulfide includes the following steps: After the tin source and sulfur source are mixed evenly, they are fully reacted under heating conditions of 175-185℃. After cooling, they are soaked in water, and after solid-liquid separation, the solid is dried to obtain nano-flower-shaped tin disulfide.

9. The application of the ion battery composite material according to any one of claims 1 to 6 in the preparation of the negative electrode of an ion battery.

10. A potassium-ion battery, characterized in that, The negative electrode of the potassium-ion battery comprises the ion battery composite material according to any one of claims 1 to 6.

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