Nano-diamond high-strength supporting composite material as well as preparation method and application of nano-diamond high-strength supporting composite material

Abstract

The invention provides a nano-diamond high-strength supporting composite material and a preparation method and application thereof, the nano-diamond high-strength supporting composite material comprises a substrate, a polymer layer and a porous layer which are arranged in sequence; the porous layer comprises a nano-diamond array and an electrode active material layer; the nano-diamond array is arranged on the polymer layer and is embedded by the electrode active material layer. The surface porous layer can dredge ion deposition and improve ion deposition sites; the nano-diamond array serves as a buffer framework and can restrain volume expansion in the aluminum alloying process, the integrity of the overall structure is kept, and electrode pulverization is effectively relieved. The surface of the diamond array is coated with an electrode active material layer, and a continuous electronic path is provided; and the two layers also form a compact interlayer bonding structure, so that stress can be effectively dispersed, the adhesive force of the porous surface layer is improved, interface fracture and stripping of the porous surface layer are avoided, and the performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond thin films, and particularly relates to a high-strength support composite material with nanodiamonds, a preparation method thereof, and an application thereof. Background Art

[0002] Lithium-ion batteries have become one of the most important secondary batteries at present due to their high energy density, long cycle life, and good safety performance. They dominate in fields such as consumer electronics, electric vehicles, and energy storage systems. With the continuous improvement of application requirements, the improvement of the anode material has become one of the key factors for enhancing the overall performance of the battery. The aluminum metal anode shows the potential to improve the energy density of the battery and reduce costs due to its high theoretical specific capacity, abundant resources, and good thermal conductivity, and is widely used in the field of lithium-ion batteries. However, its severe volume expansion greatly reduces the cycle stability and safety of the battery during charge and discharge.

[0003] Regarding the modification of the aluminum anode of lithium-ion batteries, researchers have proposed various methods. For example, methods such as mechanical ball milling, chemical synthesis, or vapor deposition are used to nanometerize aluminum powder or aluminum anode materials. After nanometerization, the specific surface area of the nanometer particles of the material is large and they are prone to aggregation, resulting in particle agglomeration, which may reduce the uniformity and cycle stability of the electrode. Coating a protective or conductive coating, such as a carbon material, a metal oxide, or other functional materials, on the surface of the aluminum anode to form an artificial interface layer to improve the stability and conductivity of the aluminum surface. However, if the coating deposition is uneven or the bonding with the substrate is insufficient, the coating will peel off due to volume changes during the cycle, thus greatly reducing the improvement effect. At the same time, although the coating material can play a protective role, it may not have a high specific capacity itself. If it is too thick, it will dilute the energy density of the overall anode; alloying with other metals (such as silicon, tin, lithium, etc.) enables the aluminum anode to form stable compounds during charge and discharge, thereby reducing the severe expansion and contraction of a single metal in terms of volume change and improving the cycle life at the same time. However, alloying often reduces the theoretical specific capacity of the aluminum anode. After introducing other components, the overall specific capacity is the weighted average of each component part, which may be lower than the high theoretical value of pure aluminum. Forming a uniform and stable alloy phase requires strict control of process parameters. Otherwise, local structural inhomogeneity or phase separation is likely to occur, affecting the long-term stability of the electrode. Some alloying processes require high temperatures or special atmospheres, presenting certain challenges in large-scale production.

[0004] The related art discloses an aluminum electrode with a diamond layer on its surface. A layer of diamond is deposited on one side of an aluminum foil substrate as the negative electrode material of a lithium-ion battery. The diamond layer is used to prevent the volume expansion caused by the insertion and extraction of lithium ions in the aluminum electrode, and to avoid the pulverization of the electrode. However, the deposition of diamond on the surface of the aluminum foil will hinder the efficient transport of ions in the negative electrode, resulting in a relatively large internal resistance of the overall battery, thereby affecting the discharge efficiency and rate performance of the battery. When growing diamond on an aluminum substrate by CVD, relatively high temperatures and special environmental conditions are often required. Although there is a substrate cooling device and the aluminum foil will not show a melting phenomenon, the temperature range required for diamond growth is between 500°C and 640°C. At high temperatures, thermal damage may be introduced to the aluminum foil or microstructural defects such as Figure 1 as shown, thus affecting the uniformity of the coating and the performance of the overall electrode. SUMMARY OF THE INVENTION

[0005] In order to overcome at least one of the above technical problems existing in the prior art, one of the objectives of the present invention is to provide a high-strength support composite material with nanodiamond.

[0006] Another objective of the present invention is to provide a preparation method of the above-mentioned high-strength support composite material with nanodiamond.

[0007] Another objective of the present invention is to provide an application of the above-mentioned high-strength support composite material with nanodiamond In order to achieve the above objectives, the technical solutions adopted by the present invention are as follows: The first aspect of the present invention provides a high-strength support composite material with nanodiamond, including a substrate, a polymer layer, and a porous layer arranged in sequence; the porous layer includes a nanodiamond array and an electrode active material layer; the nanodiamond array is arranged on the polymer layer and is embedded by the electrode active material layer.

[0008] According to some embodiments of the first aspect of the present invention, the thickness of the electrode active material layer is less than the average particle size of the nanodiamond.

[0009] According to some embodiments of the first aspect of the present invention, in the nanodiamond array, the nanodiamond is spherical and / or quasi-spherical; the average particle size of the nanodiamond is 20 - 2000 nm.

[0010] According to some embodiments of the first aspect of the present invention, the thickness of the electrode active material layer is 50 - 600 nm.

[0011] According to some embodiments of the first aspect of the present invention, the amount of polymer in the polymer layer provided on the substrate is 3×10 -6 ~3×10 -4 g / cm 2。

[0012] According to some embodiments of the first aspect of the present invention, the amount of the nanodiamond array provided on the polymer layer is 1×10 -9 ~1×10 -7 g / cm 2 。

[0013] According to some embodiments of the first aspect of the present invention, the material of the polymer layer includes at least one of polydimethyldiallylammonium chloride, polyvinyl alcohol, polystyrene, poly(lactic acid-glycolic acid) copolymer, and polyacrylamide.

[0014] According to some embodiments of the first aspect of the present invention, the electrode active material includes at least one of sodium, potassium, calcium, aluminum, tin, zinc, antimony, bismuth, germanium, silicon, titanium, and magnesium.

[0015] According to some embodiments of the first aspect of the present invention, the material of the substrate includes at least one of aluminum, copper, zinc, gold, silver, nickel, titanium, platinum, stainless steel, molybdenum, tungsten, niobium, tantalum, graphene, carbon fiber cloth, and carbon nanotubes.

[0016] The second aspect of the present invention provides a negative electrode of a secondary battery, including an active functional material layer, and the active functional material layer includes the high-strength supported composite material with nanodiamonds.

[0017] The third aspect of the present invention provides a method for preparing the high-strength supported composite material with nanodiamonds, including the following steps: After depositing a polymer layer on a substrate, deposit a nanodiamond array, and sputter an electrode active material layer to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength supported composite material with nanodiamonds.

[0018] According to some embodiments of the first aspect of the present invention, the method for preparing the high-strength supported composite material with nanodiamonds includes the following steps: Place the substrate in a polymer solution to deposit a polymer layer, then place it in a nanodiamond suspension to deposit a nanodiamond array, and magnetron sputter an electrode active material layer to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength supported composite material with nanodiamonds.

[0019] The fourth aspect of the present invention provides a secondary battery, including the high-strength supported composite material with nanodiamonds or the negative electrode of the secondary battery. Description of the Drawings

[0020] Figure 1 is a diagram of the deformation of the substrate caused by CVD growth of diamond in the prior art.

[0021] Figure 2Schematic diagram of the preparation process of the composite material of the present invention.

[0022] Figure 3 Schematic diagram of the structure of the composite material of the present invention.

[0023] Figure 4 XRD patterns of the aluminum foil and the composite material in Example 1 of the present invention.

[0024] Figure 5 Charge-discharge curves of the full cell when the composite material in Example 1 of the present invention is used as the negative electrode material.

[0025] Figure 6 Comparison chart of the long cycle performance of the full cell when the composite material in Example 1 of the present invention and the material in Comparative Example 1 are used as the negative electrode materials.

[0026] Reference numerals: 1, nanodiamond; 2, aluminum layer; 3, polymer layer; 4, substrate. Detailed implementation manners

[0027] The following further describes the specific implementation of the present invention in detail in conjunction with the drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. The reagents or instruments used without indicating the manufacturer can be obtained as conventional products through commercial purchase.

[0028] An embodiment of the first aspect of the present invention relates to a composite material with high-strength support of nanodiamonds, including a substrate, a polymer layer, and a porous layer arranged in sequence; the porous layer includes a nanodiamond array and an electrode active material layer; the nanodiamond array is arranged on the polymer layer and is embedded by the electrode active material layer.

[0029] According to the embodiment of the first aspect of the present invention, it has at least the following beneficial effects: In the present invention, the surface porous layer can conduct ion deposition and increase ion deposition sites; among them, the nanodiamond array has high hardness and mechanical strength, and as a buffer skeleton, it can inhibit the volume expansion during the aluminization process, maintain the integrity of the overall structure, and effectively alleviate electrode pulverization. Then, an electrode active material layer is coated on the surface of the diamond array to provide a continuous electron path; the embedding of the nanodiamond array by the electrode active material layer can also repair the conductive problem between the nanometer and the substrate; the two also form a dense interlayer bonding structure, which can effectively disperse stress, improve the adhesion of the porous surface layer, avoid interface fracture and peeling of the porous surface layer, thereby improving the performance.

[0030] According to some embodiments of the first aspect of the present invention, the thickness of the polymer layer is 50 - 600 nm.

[0031] According to some embodiments of the first aspect of the present invention, the amount of polymer in the polymer layer disposed on the substrate is 3×10 -6 ~3×10 -4 g / cm 2 .

[0032] According to some embodiments of the first aspect of the present invention, in the nano-diamond array, the nano-diamonds are spherical and / or quasi-spherical; the average particle size of the nano-diamonds is 20~2000 nm; such as 80~1500 nm, 100~1200 nm, 300~1000 nm.

[0033] According to some embodiments of the first aspect of the present invention, the amount of the nano-diamond array disposed on the polymer layer is 1×10 -9 ~1×10 -7 g / cm 2 .

[0034] According to some embodiments of the first aspect of the present invention, the thickness of the electrode active material layer is less than the average particle size of the nano-diamonds. This structure makes the surface of the composite material present a porous structure with a disordered array, improves the specific surface area of the composite material, increases the active sites, and plays a role in guiding ion transport to a certain extent. The high-strength support of the nano-diamonds inhibits volume expansion, greatly improving its cycle stability and safety.

[0035] According to some embodiments of the first aspect of the present invention, the thickness of the electrode active material layer is 50~600 nm.

[0036] According to some embodiments of the first aspect of the present invention, the material of the polymer layer includes at least one of polydimethyldiallylammonium chloride, polyvinyl alcohol, polystyrene, poly(lactic-co-glycolic acid), and polyacrylamide.

[0037] According to some embodiments of the first aspect of the present invention, the electrode active material includes at least one of sodium, potassium, calcium, aluminum, tin, zinc, antimony, bismuth, germanium, silicon, titanium, and magnesium.

[0038] According to some embodiments of the first aspect of the present invention, the material of the substrate includes at least one of aluminum, copper, zinc, gold, silver, nickel, titanium, platinum, stainless steel, molybdenum, tungsten, niobium, tantalum, graphene, carbon fiber cloth, and carbon nanotubes. In the present invention, when the substrate material and the electrode active material are the same, the two have excellent electron affinity and can also provide a continuous electron path.

[0039] An embodiment of the second aspect of the present invention relates to a negative electrode of a secondary battery, including an active functional material layer, and the active functional material layer includes the composite material with high-strength support of nano-diamonds described above.

[0040] According to the embodiments of the second aspect of the present invention, it has at least the following beneficial effects: When the high-strength supported nanodiamond composite material of the present invention is used as the negative electrode active functional material of a secondary battery, no additional conductive agent and binder are required, which improves the overall electrochemical performance and energy density of the electrode. In the present invention, the high-strength supported nanodiamond composite material has high mechanical strength, stable structure, and improved ion transport efficiency, significantly improving the rate performance, cycle life, and safety of the battery.

[0041] The embodiment of the third aspect of the present invention relates to a preparation method of the high-strength supported nanodiamond composite material, including the following steps: After depositing a polymer layer on a substrate, a nanodiamond array is deposited, and an electrode active material layer is sputtered to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength supported nanodiamond composite material.

[0042] According to some embodiments of the first aspect of the present invention, the preparation method of the high-strength supported nanodiamond composite material includes the following steps: placing the substrate in a polymer solution to deposit a polymer layer, then placing it in a nanodiamond suspension to deposit a nanodiamond array, and magnetron sputtering an electrode active material layer to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength supported nanodiamond composite material.

[0043] According to some embodiments of the first aspect of the present invention, in the deposition of the polymer layer, the mass concentration of the polymer solution is 1-50 wt%; the deposition time is 1-30 min.

[0044] According to some embodiments of the first aspect of the present invention, in the deposition of the nanodiamond array, the mass concentration of the nanodiamond suspension is 0.1-50 wt%; the deposition time is 1-30 min.

[0045] According to some embodiments of the first aspect of the present invention, the nanodiamond suspension is prepared by ultrasonic dispersing nanodiamond powder in water; the ultrasonic dispersion time is 10-30 min.

[0046] According to some embodiments of the first aspect of the present invention, in the magnetron sputtering of the electrode active material layer, the process parameters of the magnetron sputtering include: the chamber pressure is 5×10 -3 Pa, argon is introduced, the gas flow rate is 5-100 sccm (such as 10-90 scccm), the sputtering power of the electrode active material target is 10-120 W, the sputtering time is 5-90 min, the substrate bias voltage is 0-30 V (such as 5-25 V), and the substrate rotation speed is 0-20 rpm (such as 3-15 rpm).

[0047] According to some embodiments of the first aspect of the present invention, the method for preparing the high-strength supported composite material with nanodiamond further includes a step of pre-treating the substrate. The specific operation of the pre-treatment includes alkali-washing the substrate and then successively ultrasonic washing it in ethanol and deionized water. The alkali-washing includes alkali-washing in a sodium hydroxide solution with a concentration of 1-5 wt% to remove the surface oxide film. The time for ultrasonic washing is 3-10 minutes.

[0048] Embodiments of the fourth aspect of the present invention relate to a secondary battery, including the high-strength supported composite material with nanodiamond or the negative electrode of the secondary battery described above.

[0049] Example 1 In this example, a composite material is prepared. Figure 2 The preparation flow chart of the material is shown, and the specific process is as follows: Preparation of nanodiamond suspension: Weigh 0.3 g of nanodiamond powder with a particle size of 500 nm and place it in 300 mL of deionized water. Ultrasonically disperse it for 20 minutes to obtain a uniformly dispersed nanodiamond suspension with a mass fraction of 10%.

[0050] Substrate pre-treatment: Take an aluminum foil with a purity ≥ 99.9% and a thickness of 20 μm, and alkali-wash it with a sodium hydroxide solution with a mass fraction of 3% to remove the surface oxide film. Immerse the aluminum foil after removing the oxide layer in ethanol and deionized water successively and ultrasonically wash it for 5 minutes, and then dry it with nitrogen. Place the cleaned substrate in a 10 wt% PDDAC (poly(diallyldimethylammonium chloride)) solution and immerse it. After standing for 10 minutes, rinse it with deionized water and dry it with nitrogen.

[0051] Preparation of nanodiamond@aluminum substrate: Immerse the dried substrate in the nanodiamond suspension. After standing for 10 minutes, rinse it with deionized water and dry it at 60 °C for 1 hour, denoted as NDs@Al composite material.

[0052] Preparation of aluminum coating@nanodiamond@aluminum substrate: Place the pre-treated nanodiamond@aluminum substrate in the vacuum chamber of a magnetron sputtering device, and take an aluminum target with a purity ≥ 99.999%. Pump the chamber pressure to 5×10 -3 Pa, introduce argon gas, the gas flow rate is 40 sccm, the aluminum target sputtering power is 60 W, the substrate bias voltage is 10 V, and the substrate rotation speed is 10 rpm, denoted as Al@NDs@Al composite material.

[0053] Figure 3 It is a schematic structural diagram of the composite material.

[0054] Figure 4: This is the XRD spectrum of the Al@NDs@Al composite material in Example 1. It can be seen that the Al@NDs@Al composite material is a composite material with an aluminum coating on the surface of nanodiamond after magnetron sputtering. Compared with aluminum foil, it has the peak of metallic aluminum and the peak of nanodiamond, and the (111) peak is at 43.9°.

[0055] Comparative Example 1 This comparative example prepares a composite material, which differs from Example 1 in that it does not contain an aluminum coating, and the remaining preparation steps are the same as those of Example 1.

[0056] Example 2 This embodiment prepares a battery, and the specific process is as follows: The Al@NDs@Al composite material after magnetron sputtering in Example 1 and the NDs@Al composite material obtained in Comparative Example 1 were cut into negative electrode sheets of appropriate size and placed in a glove box for standby use. The positive electrode sheet of the battery adopts a graphite positive electrode. The preparation process is as follows: expandable graphite, Surper P (conductive carbon black), and PVDF (polytetrafluoroethylene) are weighed in a mortar in a ratio of 8:1:1, and then fully ground and then NMP (N-methylpyrrolidone solvent) is added. The slurry is quickly ground into a uniform slurry; the slurry is evenly coated on the surface of the aluminum foil, and the surface density of the electrode sheet is controlled to be 10 mg / cm 2 , vacuum dried at 80℃ for 12 h, cut the dried electrode sheets into pieces of suitable size, weigh them and place them in a glove box for later use. Preparation of diaphragm: Cut the glass fiber paper into suitable size, dry them in a drying oven and place them in a glove box as diaphragms for later use. Preparation of electrolyte: In a glove box with argon atmosphere, weigh 4M LiPF6 and add it to 10mL ethyl methyl carbonate (EMC) solvent, add 2% vinylene carbonate (VC), and stir evenly until LiPF6 is completely dissolved. Battery assembly: In a glove box with argon atmosphere, stack the negative electrode and diaphragm prepared above in sequence, add an appropriate amount of electrolyte, then put in the positive electrode piece, encapsulate it in the battery shell, and complete the assembly.

[0057] The electrochemical performance of the prepared secondary battery was tested using the NEWARE battery testing system. The test results are as follows: Figure 5 , Figure 6 shown.

[0058] Figure 5 This is the charge and discharge curve of the full battery when the material of Example 1 is used as the negative electrode material.

[0059] Figure 6 This is a comparison chart of the long cycle performance of the full battery when the material of Example 1 and the material of Comparative Example 1 are used as negative electrode materials.

[0060] The results of electrochemical performance tests show that the Al@NDs@Al composite anode has higher cycling stability. When cycled at a high rate of 5C, the capacity retention rate reaches 81% after 2000 cycles, which is 320% higher than that of the NDs@Al composite anode without an aluminum coating (capacity retention rate of 80% after 620 cycles), as shown in Figure 5 .

[0061] Examples 3 - 18 Examples 3 - 18 are the same as Example 1 in all steps and the reagent materials used, except that the aluminum foil is replaced with different substrate materials. At the same time, the lithium-based dual-ion batteries of Examples 3 - 18 are subjected to electrochemical performance tests and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0062] Table 1

[0063] As can be seen from the table, when depositing diamond layers and aluminum coatings on different substrate materials, the prepared batteries are significantly superior to the comparative examples in terms of specific capacity and cycle number. Among them, the battery using aluminum foil as the substrate shows the best performance in both specific capacity and cycle number. This may be attributed to the fact that the PVD aluminum layer and the aluminum substrate are isomorphous. During the sputtering process, high-energy ions not only clean the substrate surface but also promote the "embedding" of coating atoms and the formation of metal bonds, enabling the aluminum coating and the aluminum substrate to achieve a firm bond at the atomic scale. At the same time, ion-assisted deposition further enhances the chemical affinity, significantly reduces the interfacial resistance, and improves the bonding strength, thus endowing the composite anode with the best electrochemical performance.

[0064] Examples 19 - 35 Examples 19 - 35 are the same as Example 1 in all steps and the reagent materials used, except that the particle size of the nanodiamonds used is different. At the same time, the lithium-based dual-ion batteries of Examples 19 - 35 are subjected to electrochemical performance tests and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0065] Table 2

[0066] As can be seen from the table, the particle size of nanodiamond has a significant impact on the electrochemical performance of the Al@NDs@Al composite material. The best performance appears when using nanodiamond with a particle size of 500 nm, at which time the specific capacity and cycle number are the highest. When the particle size is in the range of 120 - 1000 nm, the specific capacity and cycle number can still maintain good performance. However, the greater the difference between the particle size and 500 nm, the smaller the cycle number. When the particle size is too small (e.g., below 100 nm), the thickness of the aluminum coating is much larger than that of the nanodiamond layer, and a porous structure will not form on the surface of the composite material, resulting in a decline in the ability to conduct ions for deposition in the battery and affecting the electrochemical performance. When the particle size is too large (e.g., above 1200 nm), as the particle size increases, the distance between nanodiamond particles becomes smaller and the distribution of nanodiamond becomes denser. The aluminum coating can only be deposited on the surface of the diamond layer, and no porous structure can be formed, both of which will lead to a reduction in the electrochemical performance of the electrode structure.

[0067] Examples 36 - 53 Examples 36 - 53 are the same as Example 1 in all other steps and the reagent materials used, except for the mass fraction / immersion time of the PDDAC (poly(diallyldimethylammonium chloride)) solution. At the same time, the lithium-based dual-ion batteries of Examples 36 - 53 were tested for their electrochemical performance and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0068] Table 3

[0069] As can be seen from the table, the mass fraction / immersion time of the poly(diallyldimethylammonium chloride) solution has a significant impact on the electrochemical performance of the Al@NDs@Al composite material. If the mass fraction of poly(diallyldimethylammonium chloride) is too small (e.g., 1 wt%) or the immersion time is too short (e.g., 1 min), there will not be enough adsorption sites on the substrate surface, resulting in too little nanodiamond content on the substrate surface. If the mass fraction is too large (e.g., above 50 wt%) or the solution immersion time is too long (e.g., above 30 min), the polymer layer will be too thick, leading to too high a content of adsorbed nanodiamond and affecting the conductivity of the battery.

[0070] Examples 54 - 73 Examples 54 - 73 are the same as Example 1 in all other steps and the reagent materials used, except for the mass fraction / immersion time of the nanodiamond suspension. At the same time, the lithium-based dual-ion batteries of Examples 54 - 73 were tested for their electrochemical performance and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0071] Table 4

[0072] As can be seen from the table, the mass fraction / immersion time of the nanodiamond suspension has a significant impact on the electrochemical performance of the Al@NDs@Al composite material. Different mass fractions / immersion times of the nanodiamond suspension result in different deposition contents of nanodiamonds on the substrate surface. When the mass fraction is 10% and the immersion time is 10 min (Example 1), the specific capacity and the number of cycles are the highest. When the mass fraction is too low (such as 0.1 wt%) or the immersion time is too short (such as 1 min), the content of nanodiamonds is too low to effectively relieve the volume expansion of the electrode during charge and discharge. Nanodiamonds have good thermal conductivity. When the content is too low, they cannot effectively dissipate heat during high-rate charge and discharge of the battery, resulting in a decrease in lifespan. When the mass fraction is too high (such as above 50 wt%) or the immersion time is too long (such as above 30 min), the content of nanodiamonds is too high. Since nanodiamonds themselves are not conductive, it will increase the internal resistance of the battery and affect the battery performance.

[0073] Examples 74 - 87 Examples 74 - 87 are the same as Example 1 in all other steps and the reagent materials used, except for the magnetron sputtering deposition time. At the same time, the electrochemical performance of the lithium-based dual-ion batteries of Examples 74 - 87 was tested and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0074] Table 5

[0075] As can be seen from the table, different magnetron sputtering deposition times have a significant impact on the electrochemical performance of the Al@NDs@Al composite material. The magnetron sputtering time determines the thickness of the aluminum coating. If the aluminum coating is too thin (below 50 nm), it may not provide enough electron conduction paths, resulting in a decrease in the overall conductivity of the electrode and affecting the rate performance of the battery. It may not be able to effectively fill the surface irregularities of the nanodiamond layer, resulting in poor interfacial contact, increasing the contact resistance, and affecting the stability of the electrode. An aluminum coating with a thickness too large (above 600 nm) may generate large mechanical stresses due to volume changes during charge and discharge, resulting in coating cracking or peeling, and affecting the cycle stability of the electrode.

[0076] Examples 88 - 98 Examples 88 - 98 are the same as Example 1 in all other steps and the reagent materials used, except for the sputtering power during magnetron sputtering. At the same time, the electrochemical performance of the lithium-based dual-ion batteries of Examples 88 - 98 was tested and compared with the performance of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0077] Table 6

[0078] As can be seen from the table, different magnetron sputtering powers have a significant impact on the electrochemical performance of the Al@NDs@Al composite material. The magnitude of the sputtering power directly affects the deposition rate, microstructure, bonding strength, and internal stress of the aluminum coating, thereby changing the interfacial resistance, conductivity, and cycling stability of the composite anode. At low power (e.g., within 10 W), the energy of the sputtered atoms is insufficient, resulting in a decrease in the deposition rate and a reduction in the film density. The interfacial contact resistance increases, the electron transfer efficiency decreases, and the rate performance of the electrode deteriorates. The kinetic energy of the sputtered particles is low, and it is difficult for the film to form sufficient "embedding" and atomic bonding with the substrate, leading to insufficient bonding strength. After multiple cycles, microcracks or coating peeling are likely to occur, reducing the cycle life. When the power is too high (e.g., above 120 W), the deposition rate increases significantly, and the film exhibits an ultra-high density state. The high density is accompanied by intense ion bombardment and large stress accumulation. The film is more likely to generate microcracks or overall peeling during cycling, resulting in rapid capacity decay.

[0079] Examples 99 - 108 Examples 99 - 108 are the same as Example 1 in all steps and the reagent materials used, except for the argon gas flow rate during magnetron sputtering. At the same time, the electrochemical performance of the lithium-based dual-ion batteries of Examples 99 - 108 was tested and compared with that of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0080] Table 7

[0081] As can be seen from the table, different gas flow rates during magnetron sputtering have a significant impact on the electrochemical performance of the Al@NDs@Al composite material. The magnitude of the argon (Ar) gas flow rate will significantly change the plasma characteristics, film deposition rate, bonding strength, and residual stress, thereby directly affecting the conductivity, interfacial stability, and cycling performance of the electrode. At low flow rates (e.g., below 5 sccm), the concentration of reactants in the deposition area is insufficient, resulting in a decrease in the deposition rate and affecting the growth efficiency and uniformity of the film. At high flow rates (e.g., above 100 sccm), the number of ion bombardments per unit volume is higher, and the cumulative residual compressive stress of the film is greater. When the stress exceeds the crack resistance limit of the film itself, microcracks will occur, reducing the electrochemical performance of the electrode material.

[0082] Examples 109 - 119 Examples 109 - 119 are the same as Example 1 in all steps and the reagent materials used, except for the substrate bias / rotational speed during magnetron sputtering. At the same time, the electrochemical performance of the lithium-based dual-ion batteries of Examples 109 - 119 was tested and compared with that of Example 1 of the present invention. The specific electrochemical performance is shown in the following table.

[0083] Table 8

[0084] As can be seen from the table, different substrate biases / substrate rotation speeds during magnetron sputtering have a significant impact on the electrochemical performance of the Al@NDs@Al composite material. If the substrate bias is too small (e.g., 0 V), the atomic bonding between the film and the substrate will be insufficient, and the finally formed structure will be loose. After multiple charge-discharge cycles, the film is prone to peeling, resulting in accelerated capacity decay. When the substrate bias is too large (e.g., above 30 V), intense ion bombardment introduces a large amount of compressive stress, and microcracks and delamination are likely to occur in the coating, reducing mechanical stability and cycle life. If the substrate rotation speed is too small (e.g., 0 rpm), the center of the deposition surface is thick and the edge is thin, resulting in inconsistent local current density and large fluctuations in electrochemical performance. When the substrate rotation speed is too large (e.g., above 20 rpm), the plasma distribution is unstable under high-speed rotation, and the substrate stays under the target for too short a time, resulting in uneven thickness, reducing mechanical and electrochemical stability, and affecting the overall performance of the electrode.

[0085] The above has described the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments. Within the knowledge scope of those of ordinary skill in the art to which the present invention pertains, various changes can be made without departing from the gist of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A high-strength supported composite material with nanodiamond, characterized in that: It includes a substrate, a polymer layer, and a porous layer arranged in sequence; the porous layer includes a nanodiamond array and an electrode active material layer; the nanodiamond array is disposed on the polymer layer and is embedded in the electrode active material layer.

2. The high-strength supported composite material with nanodiamond according to claim 1, wherein: The thickness of the electrode active material layer is less than the average particle size of the nanodiamonds.

3. The high-strength support composite material with nanodiamond according to claim 1, wherein: In the nanodiamond array, the nanodiamonds are spherical and / or quasi-spherical; the average particle size of the nanodiamonds is 20 - 2000 nm; the thickness of the electrode active material layer is 50 - 600 nm.

4. The high-strength supported composite material with nanodiamond according to claim 1, wherein: The amount of polymer in the polymer layer provided on the substrate is 3×10 -6 ~3×10 -4 g / cm 2 .

5. The high-strength supported composite material with nanodiamond according to claim 1, wherein: The amount of the nanodiamond array provided on the polymer layer is 1×10 -9 ~1×10 -7 g / cm 2 .

6. The high-strength supported composite material with nanodiamond according to claim 1, characterized in that: The high-strength nanodiamond-supported composite material satisfies at least one of the following conditions: (I) The material of the polymer layer includes at least one of polydimethyldiallylammonium chloride, polyvinyl alcohol, polystyrene, poly(lactic-co-glycolic acid), and polyacrylamide; (II) The electrode active material includes at least one of sodium, potassium, calcium, aluminum, tin, zinc, antimony, bismuth, germanium, silicon, titanium, and magnesium; (III) The material of the substrate includes at least one of aluminum, copper, zinc, gold, silver, nickel, titanium, platinum, stainless steel, molybdenum, tungsten, niobium, tantalum, graphene, carbon fiber cloth, and carbon nanotubes.

7. A negative electrode of a secondary battery, including an active functional material layer, and the active functional material layer includes the high-strength nanodiamond-supported composite material according to any one of claims 1 - 6.

8. A method for preparing a high-strength supported composite material with nanodiamond according to any one of claims 1 to 6, characterized in that: It includes the following steps: After depositing a polymer layer on the substrate, deposit a nanodiamond array, and sputter an electrode active material layer to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength nanodiamond-supported composite material.

9. The preparation method of the high-strength supported composite material with nanodiamond according to claim 8, characterized in that: The preparation method of the high-strength nanodiamond-supported composite material includes the following steps: Place the substrate in a polymer solution to deposit a polymer layer, then place it in a nanodiamond suspension to deposit a nanodiamond array, and magnetron sputter an electrode active material layer to embed the nanodiamond array to form a porous layer, thereby obtaining the high-strength nanodiamond-supported composite material.

10. A secondary battery, including the high-strength nanodiamond-supported composite material according to any one of claims 1 - 6 or the negative electrode of the secondary battery according to claim 7.

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