Ceramic / carbon multiphase structure thin film material and preparation method and application thereof

Abstract

The invention discloses a ceramic / carbon multiphase structure thin film material and a preparation method and application thereof, and relates to the technical field of ceramic material preparation. The preparation method of the ceramic / carbon multiphase structure thin film material comprises the following steps: taking a ceramic material as a sputtering target material, carrying out magnetron sputtering on a substrate containing a paraffin oil layer on the surface, and forming a first composite film on the substrate, the first composite membrane comprises a polymer gel membrane formed by cross-linking paraffin oil and a ceramic membrane positioned on the polymer gel membrane; immersing the substrate containing the first composite membrane on the surface into petroleum ether, standing for 2-12 hours, and stripping off the substrate to obtain a second composite membrane; and sintering the second composite film in an inert atmosphere to obtain the ceramic / carbon multiphase structure film material. Limited sintering of ceramic material particles is achieved through the polymer gel film, crystal grains are refined, the sintering temperature is reduced, and energy is saved.

Description

Technical Field

[0001] This invention relates to the field of ceramic material preparation technology, and in particular to a ceramic / carbon multiphase structure thin film material, its preparation method and application. Background Technology

[0002] In recent decades, two-dimensional materials have become a research hotspot due to their enormous application potential in electrodes, high-capacity batteries, superconducting devices, and catalysts. However, traditional solid-substrate-dependent preparation methods have significant limitations: oxide films have poor diffusivity, excessive adhesion between the film and the substrate makes non-destructive peeling difficult, and lattice matching requirements easily lead to defects such as dislocations and cracks. Therefore, there is an urgent need to develop new, universal, and economical thin-film manufacturing technologies. Liquid substrates (such as gold and silicone oil) have attracted attention as alternatives. Their lack of lattice constraints avoids dislocations and grain boundary defects, while the dynamic relaxation characteristics of the liquid interface can effectively release internal stress in the film, reducing cracks and pores. Among these, paraffin oil stands out due to its high boiling point, low molecular crosslinking degree, and excellent fluidity. It can be uniformly spread over a large area in a vacuum and is easily soluble in organic solvents, facilitating its convenient separation from the film as a sacrificial layer.

[0003] In the fabrication processes of ceramics, semiconductors, and high-performance thin film materials, sintering is a crucial step that directly affects the material's density, grain boundary structure, and performance stability. Traditional sintering techniques (such as pressureless sintering and hot pressing) rely on high-temperature environments (typically >1000℃) to drive atomic migration and achieve particle bonding, resulting in significant drawbacks such as high energy consumption and grain coarsening. Grain coarsening increases grain boundary defects in ceramics, promotes crack initiation, and leads to increased brittleness and a significant decrease in strength. Coarse grains can also cause uneven thermal properties, such as differences in the coefficient of thermal expansion, inducing internal stress. To reduce sintering temperatures, the industry has attempted to introduce nanoparticles or additives, but bottlenecks remain.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] Based on the shortcomings of the prior art, the purpose of this invention is to provide a ceramic / carbon multiphase structure thin film material, its preparation method and application, aiming to solve the problems of high sintering temperature and grain coarsening in the preparation of ceramic materials by existing sintering methods.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a ceramic / carbon multiphase thin film material, comprising the following steps:

[0008] Using ceramic material as a sputtering target, magnetron sputtering is performed on a substrate containing a paraffin oil layer on the surface to form a first composite film on the substrate. The first composite film includes a polymer gel film formed by crosslinking paraffin oil and a ceramic film located on the polymer gel film.

[0009] The substrate containing the first composite film on its surface was immersed in petroleum ether and left to stand for 2 to 12 hours. The substrate was then peeled off to obtain the second composite film.

[0010] The second composite film was sintered in an inert atmosphere to obtain a ceramic / carbon multiphase thin film material.

[0011] Optionally, the ceramic material includes Nb2O5, TiNb2O7, AlN, or MoS2.

[0012] Optionally, when the chemical composition of the ceramic material contains oxygen, the process parameters for magnetron sputtering are as follows:

[0013] Argon flow rate is 30–60 sccm, oxygen flow rate is 3–7 sccm, sample stage rotation speed is 10–15 rpm, gas pressure is 3–5 Pa, sputtering chamber pressure is 0.9–1.1 Pa, sputtering power is 80–100 W, and deposition time is 2–8 h.

[0014] When the chemical composition of the ceramic material does not contain oxygen, the process parameters for magnetron sputtering are as follows:

[0015] The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the gas pressure is 3–5 Pa, the sputtering chamber pressure is 0.9–1.1 Pa, the sputtering power is 80–100 W, and the deposition time is 2–8 h.

[0016] Optionally, a pre-sputtering step is included before magnetron sputtering; when the chemical composition of the ceramic material contains oxygen, the pre-sputtering process parameters are as follows:

[0017] Argon flow rate is 30-60 sccm, oxygen flow rate is 3-7 sccm, sample stage rotation speed is 10-15 rpm, sputtering power is 80-100 W, and deposition time is 5-10 min;

[0018] When the chemical composition of the ceramic material does not contain oxygen, the pre-sputtering process parameters are as follows:

[0019] The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the sputtering power is 80–100 W, and the deposition time is 5–10 min.

[0020] Optionally, the sintering step specifically includes:

[0021] At 2–5℃·min-1 The temperature is increased to the sintering temperature at a certain rate, and sintered at the sintering temperature for 1 to 3 hours, wherein the sintering temperature is 600 to 950°C.

[0022] Optionally, the step of immersing a substrate containing the first composite film on its surface in petroleum ether, allowing it to stand for 2–12 hours, and then peeling off the substrate to obtain the second composite film specifically includes:

[0023] The substrate containing the first composite film is placed in a container, and then petroleum ether is poured in until it covers the surface of the first composite film. After standing for 2 to 12 hours, the petroleum ether is poured out, and then anhydrous ethanol is poured in until it covers the ceramic film. After standing for 5 to 30 minutes, the second composite film is peeled off from the substrate.

[0024] In a second aspect, the present invention provides a ceramic / carbon multiphase structure thin film material, wherein it is prepared by the preparation method of the present invention as described above.

[0025] A third aspect of the present invention provides an application of the ceramic / carbon multiphase structure thin film material of the present invention as described above in the field of lithium-ion batteries.

[0026] In a fourth aspect, the present invention provides a negative electrode sheet, comprising a current collector and a dressing layer located on the surface of the current collector, the dressing layer comprising a negative electrode material obtained by grinding the ceramic / carbon multiphase structure thin film material of the present invention as described above.

[0027] A fifth aspect of the present invention provides a lithium-ion battery, comprising a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the negative electrode is the negative electrode of the present invention as described above.

[0028] Beneficial Effects: This invention utilizes the interaction between high-energy plasma and liquid paraffin oil during magnetron sputtering to form an in-situ polymer gel film (i.e., a polymer gel template) composed of a three-dimensional cross-linked network. The dynamic liquid-solid interface characteristics of this polymer gel film can effectively regulate the migration rate of deposited particles and inhibit grain agglomeration caused by surface diffusion. The confinement effect of the polymer gel film ensures that the deposited particles are uniformly distributed at the atomic scale. During inert atmosphere sintering, the three-dimensional cross-linked network in the polymer gel film forms a continuous barrier, hindering atomic diffusion paths, inhibiting grain boundary migration, and reducing grain growth kinetics, thereby achieving grain refinement. In addition, the three-dimensional cross-linked network in the polymer gel film can reduce the diffusion activity energy of ceramic material particles, thereby lowering the sintering temperature. After subsequent sintering, the polymer gel film generates a uniform carbon layer (porous carbon). The strong interaction between the carbon layer and the ceramic phase (such as covalent / ionic bonding, electronic coupling, and mechanical interlocking) inhibits grain boundary migration, forming a ceramic / carbon multiphase structure thin film material. Therefore, the method provided by this invention can refine grains, reduce sintering temperature, and save energy. This invention effectively solves the problems of high sintering temperature (high energy consumption) and grain coarsening in existing sintering methods for preparing ceramic materials. The method provided by this invention promotes the development of material preparation towards low defects, high precision, and multifunctionality, offering a new path for the manufacturing of high-performance thin films and structural components in ceramics, semiconductors, and other fields, combining process innovation with application value. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process for ceramic / carbon multiphase thin film materials.

[0030] Figure 2 The figures show the characterization results of the TiNb2O7 / carbon multiphase thin film material prepared in Example 1, where (a) is the XRD pattern and (b) is the Raman spectrum.

[0031] Figure 3 The figures show the characterization results of the Nb2O5 / carbon multiphase thin film material prepared in Example 2, where (a) is the XRD pattern and (b) is the Raman spectrum.

[0032] Figure 4 The figures show the characterization results of the AlN / carbon multiphase thin film material prepared in Example 3, where (a) is the XRD pattern and (b) is the Raman spectrum.

[0033] Figure 5 The figures show the characterization results of the MoS2 / carbon multiphase thin film material prepared in Example 4, where (a) is the XRD pattern and (b) is the Raman spectrum.

[0034] Figure 6The images are TEM images of the thin film materials obtained in Example 1 and Comparative Example 1, where (a) is the TiNb2O7 / carbon multiphase structure thin film material prepared in Example 1, and (b) is the TiNb2O7 thin film material prepared in Comparative Example 1.

[0035] Figure 7 The graph shows the cycle performance of lithium-ion batteries based on the TiNb2O7 / carbon multiphase thin film material prepared in Example 1 and the TiNb2O7 thin film material prepared in Comparative Example 1 at a temperature of -10°C and a charge / discharge current of 5C.

[0036] Figure 8 The graph shows the cycle performance of lithium-ion batteries based on the TiNb2O7 / carbon multiphase thin film material prepared in Example 1 and the TiNb2O7 thin film material prepared in Comparative Example 1 at a temperature of -20°C and a charge / discharge current of 1C. Detailed Implementation

[0037] This invention provides a ceramic / carbon multiphase structure thin film material, its preparation method, and its applications. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] If the embodiments of the present invention involve descriptions such as "first" or "second", such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0040] To overcome the bottlenecks of traditional processes, this invention employs confined sintering technology. Its core lies in precisely controlling the sintering process through physical or chemical means (such as mold constraint and nanoscale spatial confinement) to suppress abnormal grain growth and reduce internal stress. In this invention, the polymer gel film formed by the interaction of paraffin oil and plasma, consisting of a three-dimensional network structure, plays a crucial role in this technological evolution. This polymer gel film, through dynamic liquid-solid interface regulation of the migration and assembly behavior of deposited particles, forms a stable confined environment, providing a feasible path to reduce the sintering temperature of ceramic materials and suppress grain coarsening. This unique advantage of paraffin oil further promotes the innovation of confined sintering technology. The formed three-dimensional network structure acts as a framework, restricting the migration and growth of ceramic particles, achieving three-dimensional confined sintering. Specifically, embodiments of this invention provide a method for preparing ceramic / carbon multiphase structure thin film materials, wherein, as... Figure 1 As shown, it includes the following steps:

[0041] S1. Using ceramic material as a sputtering target, magnetron sputtering is performed on a substrate containing a paraffin oil layer on the surface to form a first composite film on the substrate. The first composite film includes a polymer gel film formed by crosslinking paraffin oil and a ceramic film located on the polymer gel film.

[0042] S3. Immerse the substrate containing the first composite film on its surface into petroleum ether, let it stand for 2 to 12 hours, and then peel off the substrate to obtain the second composite film.

[0043] S4. The second composite film is sintered in an inert atmosphere to obtain a ceramic / carbon multiphase thin film material.

[0044] This invention utilizes the interaction between high-energy plasma and liquid paraffin oil during magnetron sputtering to form an in-situ polymer gel film (i.e., a polymer gel template) composed of a three-dimensional cross-linked network. The dynamic liquid-solid interface characteristics of this polymer gel film can effectively regulate the migration rate of deposited particles and suppress grain agglomeration caused by surface diffusion. The confinement effect of the polymer gel film ensures that the deposited particles are uniformly distributed at the atomic scale. During inert atmosphere sintering, the three-dimensional cross-linked network in the polymer gel film forms a continuous barrier, hindering atomic diffusion paths, inhibiting grain boundary migration, and reducing grain growth kinetics, thereby achieving grain refinement. In addition, the three-dimensional cross-linked network in the polymer gel film can reduce the diffusion activity energy of ceramic material particles, thereby lowering the sintering temperature. After subsequent sintering, the polymer gel film generates a uniform carbon layer (porous carbon). The strong interaction between the carbon layer and the ceramic phase (such as covalent / ionic bonding, electronic coupling, and mechanical interlocking) inhibits grain boundary migration, forming a ceramic / carbon multiphase thin film material. This ceramic / carbon multiphase thin film material includes a carbon layer and ceramic particles dispersed within the carbon layer; that is, the carbon layer is a continuous matrix and a continuous phase, while the ceramic particles are dispersed as a discontinuous second phase, thus forming a ceramic / carbon multiphase thin film material. Therefore, the method provided by this invention can refine grains, reduce sintering temperature, and save energy. This invention effectively solves the problems of high sintering temperature (high energy consumption) and grain coarsening in existing sintering methods for preparing ceramic materials. The method provided by this invention promotes the development of material preparation towards low-defect, high-precision, and multifunctional directions, providing a new path for the manufacturing of high-performance thin films and structural components in ceramics, semiconductors, and other fields, combining process innovation with application value.

[0045] In this invention, a substrate containing a first composite film is immersed in petroleum ether and left to stand for 2 to 12 hours. This standing time ensures that the polymer gel film near the substrate is fully dissolved, while the polymer gel film near the ceramic film remains undissolved. This achieves the separation of the entire film from the substrate, while the undissolved polymer gel film remains on the ceramic film (i.e., the second composite film is composed of the ceramic film and the remaining polymer gel film after dissolution in petroleum ether). The presence of the polymer gel film achieves the purpose of confined sintering and grain control.

[0046] Under suitable magnetron sputtering conditions, paraffin oil (mainly composed of long-chain alkanes) can polymerize and form a three-dimensional cross-linked network through plasma bombardment (specifically, high-energy particles within the plasma), thereby forming a polymer gel film. This process relies on the bombardment of paraffin oil molecules by high-energy particles in the plasma, causing them to fragment, ionize, or excite, and subsequently form a cross-linked structure through free radical reactions. Furthermore, this process requires suitable pressure, time, and temperature to promote the cross-linking reaction; therefore, achieving this effect necessitates specific sputtering process conditions.

[0047] In step S1, in some embodiments, the substrate is a ceramic substrate, such as an Al2O3 substrate. Before use, the ceramic substrate is ultrasonically cleaned with ultrapure water and anhydrous ethanol for 5 to 30 minutes (e.g., 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, etc.) and then dried.

[0048] In some embodiments, the ceramic material includes Nb2O5, TiNb2O7, AlN, or MoS2, but is not limited thereto.

[0049] In some embodiments, the purity of the ceramic material is 99.9%.

[0050] In some embodiments, when the chemical composition of the ceramic material contains oxygen (e.g., the ceramic material is Nb2O5 or TiNb2O7), the process parameters for the magnetron sputtering are as follows:

[0051] The argon flow rate is 30–60 sccm (e.g., 30 sccm, 40 sccm, 50 sccm, or 60 sccm), the oxygen flow rate is 3–7 sccm (e.g., 3 sccm, 4 sccm, 5 sccm, 6 sccm, or 7 sccm), the sample stage rotation speed is 10–15 rpm (e.g., 10 rpm, 11 rpm, 12 rpm, 13 rpm, 14 rpm, or 15 rpm), the gas pressure is 3–5 Pa (e.g., 3 Pa, 4 Pa, or 5 Pa), the sputtering chamber pressure is 0.9–1.1 Pa (e.g., 0.9 Pa, 1 Pa, or 1.1 Pa), the sputtering power is 80–100 W (e.g., 80 W, 85 W, 90 W, 95 W, or 100 W), and the deposition time is 2–8 h (e.g., 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, or 8 h).

[0052] When the chemical composition of the ceramic material does not contain oxygen (e.g., the ceramic material is AlN or MoS2), the process parameters for magnetron sputtering are as follows:

[0053] The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the gas pressure is 3–5 Pa, the sputtering chamber pressure is 0.9–1.1 Pa, the sputtering power is 80–100 W, and the deposition time is 2–8 h.

[0054] In some implementations, a pre-sputtering step is also included before magnetron sputtering;

[0055] When the chemical composition of the ceramic material contains oxygen, the pre-sputtering process parameters are as follows:

[0056] Argon flow rate is 30-60 sccm, oxygen flow rate is 3-7 sccm, sample stage rotation speed is 10-15 rpm, sputtering power is 80-100 W, and deposition time is 5-10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc.).

[0057] When the chemical composition of the ceramic material does not contain oxygen, the pre-sputtering process parameters are as follows:

[0058] The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the sputtering power is 80–100 W, and the deposition time is 5–10 min.

[0059] After pre-sputtering, the paraffin oil on the surface of the paraffin oil layer is cross-linked to form a three-dimensional polymer gel composed of a three-dimensional cross-linked network. Subsequently, in the magnetron sputtering process, ceramic material particles are first embedded into the three-dimensional cross-linked network, which is more conducive to achieving subsequent confined sintering.

[0060] In some implementations, the sintering step specifically includes:

[0061] At 2–5℃·min -1 (For example, it can be 2℃·min) -1 3℃·min -1 4℃·min -1 or 5℃·min -1 The temperature is increased to the sintering temperature at a rate of (etc.), and sintered at the sintering temperature for 1 to 3 hours (e.g., 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours, etc.). The sintering temperature is 600 to 950°C (e.g., 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, or 950°C, etc.).

[0062] At 2–5℃·min -1 By rapidly increasing the temperature to the sintering temperature, the moisture and volatiles inside the material can be slowly expelled, avoiding cracking or the formation of pores caused by rapid heating.

[0063] In some embodiments, the step of immersing a substrate containing the first composite film on its surface in petroleum ether, allowing it to stand for 2–12 hours, and then peeling off the substrate to obtain the second composite film specifically includes:

[0064] The substrate containing the first composite film is placed in a container, and then petroleum ether is poured in until it covers the surface of the first composite film. After standing for 2 to 12 hours (e.g., 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours), the petroleum ether is poured out, and then anhydrous ethanol is poured in until it covers the ceramic film. After standing for 5 to 30 minutes (e.g., 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes), the second composite film is peeled off from the substrate.

[0065] In this embodiment, residual petroleum ether can be removed by standing in anhydrous ethanol for 5 to 30 minutes.

[0066] This invention also provides a ceramic / carbon multiphase structure thin film material, which is prepared using the preparation method described above.

[0067] This invention also provides an application of the ceramic / carbon multiphase structure thin film material described above in the field of lithium-ion batteries.

[0068] In some embodiments, the ceramic / carbon multiphase material is ground during application.

[0069] This invention also provides a negative electrode sheet, which includes a current collector and a dressing layer located on the surface of the current collector. The dressing layer includes a negative electrode material, which is obtained by grinding the ceramic / carbon multiphase structure thin film material of this invention as described above.

[0070] In some embodiments, the dressing layer further includes a conductive agent (such as conductive carbon black, conductive graphite, etc.) and a binder (such as polyvinylidene fluoride, carboxymethyl cellulose, etc.).

[0071] This invention also provides a lithium-ion battery, which includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the negative electrode is the negative electrode as described above.

[0072] The present invention will be further described below through specific embodiments.

[0073] In the following embodiments, the magnetron sputtering equipment used was purchased from Beijing Genesis Weina Technology Co., Ltd., and the model is MSP-3200 magnetron sputtering equipment.

[0074] Example 1

[0075] This invention provides a method for preparing a TiNb2O7 / carbon multiphase thin film material, which specifically includes the following steps:

[0076] 1) Preparation of liquid substrate

[0077] A circular Al2O3 ceramic plate with a diameter of 100 mm was ultrasonically cleaned with ultrapure water for 10 min, then ultrasonically cleaned with anhydrous ethanol for 10 min. After that, it was placed in a vacuum drying oven to dry. After it was completely dry, it was taken out and allowed to cool to room temperature. Then, 1 mL of paraffin oil was dropped onto the Al2O3 ceramic plate with a pipette. The paraffin oil was then spread evenly on the Al2O3 ceramic plate with a dropper to form a paraffin oil layer with a thickness of 0.127 mm.

[0078] 2) Thin film sputtering

[0079] An Al2O3 ceramic plate with a paraffin oil layer on its surface was placed on a sample platform and fed into the sputtering chamber using a robotic arm. A dual-target system (both TiNb2O7 targets with a purity of 99.9%) was used. The platform rotation speed was then adjusted to 15 rpm to ensure more uniform film sputtering. The process continued until the pressure inside the sputtering chamber reached 9 × 10⁻⁶. -4 When the pressure reaches 5 Pa, turn off the vacuum gauge power supply, then introduce argon gas at a flow rate of 40 sccm and oxygen gas at a flow rate of 5 sccm. After 15 minutes, adjust the pressure valve to make the pressure in the sputtering chamber reach 5 Pa.

[0080] Subsequently, sputtering was initiated after setting the sputtering power to 100W and the deposition time to 6 hours. After initiation, the pressure valve was adjusted to achieve a pressure of 1 Pa within the sputtering chamber, and pre-sputtering was performed for 10 minutes (argon flow rate 40 sccm, oxygen flow rate 5 sccm, stage speed 15 rpm, sputtering power 80W). Then, formal sputtering commenced (sputtering power 100W, deposition time 6 hours, argon flow rate 40 sccm, oxygen flow rate 5 sccm, stage speed 15 rpm). After sputtering, the stage speed and gas switches were turned off. The sample was then removed using a robotic arm, yielding the first composite film consisting of a polymer gel film and a TiNb2O7 film attached to the ceramic plate.

[0081] 3) Film post-treatment

[0082] An Al2O3 ceramic plate with the first composite film on its surface was placed in a 150mm diameter petri dish. Petroleum ether was then slowly poured into the petri dish until it completely submerged the surface of the first composite film. To prevent the petroleum ether from evaporating, the petri dish was placed in a freezer and sealed with plastic wrap. After standing for 12 hours (this standing time ensures that the polymer gel film near the Al2O3 ceramic plate is fully dissolved, while the polymer gel film near the TiNb2O7 film remains undissolved), the film was separated from the Al2O3 ceramic plate. The remaining petroleum ether in the petri dish was then poured into waste liquid, and anhydrous ethanol was slowly poured into the petri dish until it completely submerged the TiNb2O7 film. The mixture was then left to stand for 30 minutes. The film was then removed with tweezers, washed with anhydrous ethanol and deionized water, and dried to obtain the second composite film (composed of the TiNb2O7 film and the remaining polymer gel film after dissolution).

[0083] The second composite membrane was placed in an alumina crucible, then placed in a tube furnace, and nitrogen gas was introduced at 5°C / min. -1 The temperature was increased to 900℃, and then sintered at 900℃ for 3 hours under a nitrogen atmosphere to obtain a TiNb2O7 / carbon multiphase structure thin film material (composed of a carbon layer and TiNb2O7 particles dispersed therein).

[0084] X-ray diffraction (XRD) pattern and Raman spectrum of TiNb2O7 / carbon multiphase thin film material are shown below. Figure 2 As shown in the XRD pattern, the diffraction peaks of the TiNb₂O₇ / carbon composite thin film material highly coincide with those on the PDF card, indicating that the crystal phase of the prepared thin film material is the pure TiNb₂O₇ phase, without any impurities. The Raman spectrum shows that at 1342 cm⁻¹... -1 and 1596cm -1 Characteristic peaks of carbon D and G bands appeared nearby, corresponding to the disordered graphite structure and graphite sp in the TiNb2O7 / carbon multiphase thin film material, respectively. 2 The presence of carbon atoms proves that carbon is present in the TiNb2O7 / carbon multiphase thin film material prepared after annealing.

[0085] Example 2

[0086] This embodiment provides a method for preparing Nb2O5 / carbon multiphase thin film material, which differs from Example 1 only in that:

[0087] Both targets are Nb2O5 targets with a purity of 99.9%;

[0088] The specific sputtering process parameters are the same as in Example 1.

[0089] The second composite membrane (composed of an Nb₂O₅ membrane and the remaining polymer gel membrane after dissolution) was placed in an alumina crucible, then placed in a tube furnace, and nitrogen gas was introduced at 5 °C·min. -1 The temperature was increased to 700℃, and then sintered at 700℃ for 3 hours under a nitrogen atmosphere to obtain an Nb2O5 / carbon multiphase structure thin film material (composed of a carbon layer and Nb2O5 particles dispersed therein).

[0090] XRD patterns and Raman spectra of Nb2O5 / carbon multiphase thin film materials are shown below. Figure 3 As shown in the XRD pattern, the diffraction peaks of the Nb₂O₅ / carbon multiphase structure thin film material highly coincide with those on the PDF card, indicating that the crystal phase of the prepared thin film material is the pure Nb₂O₅ phase, without any impurity phases. Raman spectroscopy shows that at 1342 cm⁻¹... -1 and 1596cm -1 Characteristic peaks of carbon D and G bands appeared nearby, corresponding to the disordered graphite structure and graphite sp in the Nb2O5 / carbon multiphase thin film material, respectively. 2 The presence of carbon atoms proves that carbon is present in the Nb2O5 / carbon multiphase thin film material obtained after annealing.

[0091] Example 3

[0092] This invention provides a method for preparing an AlN / carbon multiphase thin film material, which differs from Example 1 only in that:

[0093] Both targets are AlN targets with a purity of 99.9%;

[0094] No oxygen is required during the sputtering process; other specific sputtering process parameters are the same as in Example 1.

[0095] The second composite membrane (composed of an AlN membrane and the remaining polymer gel membrane after dissolution) was placed in an alumina crucible, then placed in a tube furnace, and nitrogen gas was introduced at 5 °C·min. -1 The temperature was increased to 950℃, and then sintered at 950℃ for 3 hours under a nitrogen atmosphere to obtain an AlN / carbon multiphase thin film material (composed of a carbon layer and AlN particles dispersed therein).

[0096] XRD patterns and Raman spectra of AlN / carbon composite thin film materials are as follows: Figure 4 As shown in the figure. The XRD pattern shows that the diffraction peaks of the AlN / carbon composite thin film material highly coincide with those on the PDF card, indicating that the crystal phase of the prepared thin film material is the pure AlN phase, without any impurities. The Raman spectrum shows that at 1342 cm⁻¹... -1 and 1596cm -1Characteristic peaks of carbon D and G bands appeared nearby, corresponding to the disordered graphite structure and graphite sp in the AlN / carbon multiphase thin film material, respectively. 2 The presence of carbon atoms proves that carbon is present in the AlN / carbon composite thin film material obtained after annealing.

[0097] Example 4

[0098] Example 4 of this invention provides a method for preparing a MoS2 / carbon multiphase thin film material, which differs from Example 1 only in that:

[0099] Both targets are MoS2 targets with a purity of 99.9%;

[0100] The sputtering conditions do not require the use of oxygen; other specific sputtering process parameters are the same as in Example 1.

[0101] The second composite membrane (composed of a MoS2 membrane and the remaining polymer gel membrane after dissolution) was placed in an alumina crucible, then placed in a tube furnace, and nitrogen gas was introduced at 5°C / min. -1 The temperature was increased to 600℃, and then sintered at 600℃ for 3 hours under a nitrogen atmosphere to obtain a MoS2 / carbon multiphase structure thin film material (composed of a carbon layer and MoS2 particles dispersed therein).

[0102] XRD patterns and Raman spectra of MoS2 / carbon multiphase thin film materials are as follows: Figure 5 As shown in the figure. The XRD pattern shows that the diffraction peaks of the MoS2 / carbon composite thin film material highly coincide with those on the PDF card, indicating that the crystal phase of the prepared thin film material is the pure MoS2 phase, without any impurities. The Raman spectrum shows that at 1342 cm⁻¹... -1 and 1596cm -1 Characteristic peaks of carbon D and G bands appeared nearby, corresponding to the disordered graphite structure and graphite sp in the MoS2 / carbon multiphase thin film material, respectively. 2 The presence of carbon atoms proves that carbon is present in the MoS2 / carbon multiphase thin film material obtained after annealing.

[0103] Comparative Example 1

[0104] This comparative example provides a method for preparing TiNb2O7 thin film material, which differs from Example 1 only in that:

[0105] Finally, sintering is carried out in an air atmosphere (in an air atmosphere, the polymer gel film undergoes oxidative decomposition, making subsequent confined sintering impossible).

[0106] The transmission electron microscope (TEM) image of the TiNb2O7 / carbon multiphase thin film material prepared in Example 1 is shown below. Figure 6As shown in (a) above, the TEM image of the TiNb2O7 thin film material prepared in Comparative Example 1 is as follows. Figure 6 As shown in (b) above, the material prepared in Example 1 has a smaller grain size and is dispersed in the amorphous medium, exhibiting a continuous network morphology. The material prepared in Comparative Example 1 is not distributed in the medium; its grain size is much larger than that of Example 1, and the grains are closely packed together or have large pores. The difference in morphology and size between the two demonstrates that the confined sintering method provided by this invention has the effect of refining grains.

[0107] The TiNb2O7 / carbon multiphase structure thin film material prepared in Example 1 and the TiNb2O7 thin film material prepared in Comparative Example 1 were ground in a mortar until uniformly dispersed to obtain powder materials, which were respectively denoted as TiNb2O7 / carbon powder material and TiNb2O7 powder material. These were used as negative electrode materials for lithium-ion batteries and assembled into lithium-ion batteries according to the following method:

[0108] (1) TiNb2O7 / carbon powder material, conductive carbon black, and polyvinylidene fluoride were mixed evenly at a ratio of 8:1:1 and placed in a degassing box. Then, a certain amount of N-methylpyrrolidone (the mass ratio of polyvinylidene fluoride to N-methylpyrrolidone was 1:1) was added to the degassing box as a solvent. The degassing box was placed in a degassing machine and mixed for 40 minutes to obtain a slurry. The obtained slurry was evenly coated on the surface of copper foil and dried overnight in an oven at 80°C. Next, the slurry was cut into 12mm diameter circular electrode sheets using a coin cell slicing machine, and the mass of active material in each circular electrode sheet was weighed and calculated.

[0109] A circular electrode sheet is used as the working electrode, a lithium sheet as the counter electrode, a polypropylene porous membrane as the battery separator, and an electrolyte (composed of LiPF6, ethylene carbonate and diethyl carbonate). The battery casing adopts a 2030 type button cell casing as the lithium-ion battery casing. The button cell is assembled in an argon-filled glove box and is referred to as a TiNb2O7 / carbon battery.

[0110] Using the same method described above, a button cell was prepared using TiNb2O7 powder material (obtained by grinding the thin film material in Comparative Example 1), denoted as TiNb2O7 cell.

[0111] Subsequently, the battery was subjected to charge-discharge cycle tests at low temperatures (-10℃, -20℃) and different current densities (1C, 5C). The test results are shown in Table 1. Figure 7 and Figure 8 As shown.

[0112] Table 1. Results of constant current charge-discharge tests on TiNb2O7 / carbon battery and TiNb2O7 battery at low temperature.

[0113]

[0114] Table 1 shows that the TiNb2O7 / carbon battery can stably cycle for 8000 cycles at -10℃ and 5C current density, with a specific capacity of 77.0 mAh·g. -1 The capacity retention rate reaches 99.0%. It can stably cycle for 2500 cycles at -20℃ and a 1C current density, and the electrode specific capacity is 155.6 mAh·g. -1 The capacity retention rate can reach 97.6%.

[0115] Figure 7 and Figure 8 This indicates that, as cycling progresses, the discharge specific capacity of the TiNb2O7 / carbon battery based on the thin film material prepared in Example 1 is much higher than that of the TiNb2O7 battery based on the thin film material prepared in Comparative Example 1 at the same number of cycles; and the TiNb2O7 / carbon battery based on the thin film material prepared in Example 1 exhibits superior cycling stability at low temperatures compared to the TiNb2O7 battery based on the thin film material prepared in Comparative Example 1.

[0116] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a ceramic / carbon multiphase thin film material, characterized in that, Includes the following steps: Using ceramic material as a sputtering target, magnetron sputtering is performed on a substrate containing a paraffin oil layer on the surface to form a first composite film on the substrate. The first composite film includes a polymer gel film formed by crosslinking paraffin oil and a ceramic film located on the polymer gel film. The substrate containing the first composite film on its surface was immersed in petroleum ether and left to stand for 2 to 12 hours. The substrate was then peeled off to obtain the second composite film. The second composite film was sintered in an inert atmosphere to obtain a ceramic / carbon multiphase thin film material.

2. The preparation method according to claim 1, characterized in that, The ceramic material includes Nb2O5, TiNb2O7, AlN, or MoS2.

3. The preparation method according to claim 1, characterized in that, When the chemical composition of the ceramic material contains oxygen, the process parameters for magnetron sputtering are as follows: Argon flow rate is 30–60 sccm, oxygen flow rate is 3–7 sccm, sample stage rotation speed is 10–15 rpm, gas pressure is 3–5 Pa, sputtering chamber pressure is 0.9–1.1 Pa, sputtering power is 80–100 W, and deposition time is 2–8 h. When the chemical composition of the ceramic material does not contain oxygen, the process parameters for magnetron sputtering are as follows: The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the gas pressure is 3–5 Pa, the sputtering chamber pressure is 0.9–1.1 Pa, the sputtering power is 80–100 W, and the deposition time is 2–8 h.

4. The preparation method according to claim 1, characterized in that, A pre-sputtering step is also included before magnetron sputtering; When the chemical composition of the ceramic material contains oxygen, the pre-sputtering process parameters are as follows: Argon flow rate is 30-60 sccm, oxygen flow rate is 3-7 sccm, sample stage rotation speed is 10-15 rpm, sputtering power is 80-100 W, and deposition time is 5-10 min; When the chemical composition of the ceramic material does not contain oxygen, the pre-sputtering process parameters are as follows: The argon flow rate is 30–60 sccm, the sample stage rotation speed is 10–15 rpm, the sputtering power is 80–100 W, and the deposition time is 5–10 min.

5. The preparation method according to claim 1, characterized in that, The sintering step specifically includes: At 2–5℃·min -1 The temperature is increased to the sintering temperature at a certain rate, and sintered at the sintering temperature for 1 to 3 hours, wherein the sintering temperature is 600 to 950°C.

6. The preparation method according to claim 1, characterized in that, The steps of immersing a substrate containing the first composite film on its surface into petroleum ether, allowing it to stand for 2–12 hours, and then peeling off the substrate to obtain the second composite film specifically include: The substrate containing the first composite film is placed in a container, and then petroleum ether is poured in until it covers the surface of the first composite film. After standing for 2 to 12 hours, the petroleum ether is poured out, and then anhydrous ethanol is poured in until it covers the ceramic film. After standing for 5 to 30 minutes, the second composite film is peeled off from the substrate.

7. A ceramic / carbon multiphase structure thin film material, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

8. The application of the ceramic / carbon multiphase structure thin film material according to claim 7 in the field of lithium-ion batteries.

9. A negative electrode sheet, characterized in that, It includes a current collector and a dressing layer located on the surface of the current collector, the dressing layer including a negative electrode material, the negative electrode material being obtained by grinding the ceramic / carbon multiphase structure thin film material of claim 7.

10. A lithium-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the negative electrode is the negative electrode as described in claim 9.

Images