Composite titanium dioxide film as well as preparation method and application thereof

Abstract

The invention provides a composite titanium dioxide film as well as a preparation method and application thereof. The preparation method of the composite titanium dioxide film comprises the following steps: performing co-sputtering treatment on a titanium dioxide target material and an energy density contribution main body element target material in an inert atmosphere, and growing the composite titanium dioxide film on a substrate. According to the preparation method of the composite titanium dioxide thin film, a titanium dioxide target material and an energy density contribution main body element target material are directly deposited by adopting a co-sputtering method to form the composite titanium dioxide thin film. The grown composite titanium dioxide film has the characteristic of small interface resistance, irreversible side reaction between electrolyte and an energy density contribution main body can be reduced and prevented, the generation of solid electrolyte membranes (SEI) is reduced, the stress of periodic volume change is reduced, and the structural stability in the lithium ion embedding / removing process is maintained. In addition, the preparation method effectively ensures that the grown composite titanium dioxide thin film is stable in chemical performance.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical power sources, and in particular relates to a composite titanium dioxide film and a preparation method and application thereof. Background Art

[0002] As a transition metal oxide, titanium dioxide is widely used in the fields of pigment production, ointment processing, water decomposition, photocatalytic elements, photoelectric conversion, energy storage, etc. due to its stability and non-toxicity in wide bandgap semiconductor materials. In addition to the stable anatase and rutile crystal structures in the tetragonal system, it also contains brookite structure, and the first two are the most commonly used crystal forms. Since the successful preparation of nanotubes, not only their one-dimensional nanostructure has unique excellent performance in electron transmission compared to the disordered stacking structure of nanoparticles, but also compared with other one-dimensional nanostructures such as nanowires and nanofibers, they have a relatively large specific surface area. Therefore, it can replace nanoparticles and play an important role and advantage in many application fields. It has achieved remarkable research results and considerable development prospects in solar cells, photocatalysis, lithium batteries, etc.

[0003] Among them, lithium batteries have become one of the most promising energy storage systems today and have been widely used due to their high capacity, high energy density, low cost, long cycle life, and high operating voltage. Among them, the performance of electrode materials directly determines the performance of lithium-ion batteries.

[0004] Since titanium dioxide has the characteristics of large lithium insertion capacity, low toxicity and low energy consumption, good stability, large specific capacity, good cycle stability, no side reactions, and high environmental protection, titanium dioxide has obvious advantages as a negative electrode material and is a very excellent raw material for lithium batteries. At present, high-voltage lithium-ion secondary batteries are made by utilizing the high safety, stability, high temperature resistance and long life of titanium dioxide. However, the current public reports on the use of titanium dioxide as a negative electrode material are almost to load titanium dioxide onto a material with an adsorption effect, such as loading titanium dioxide onto carbon nanotubes to avoid the collapse of carbon nanotube electrodes, and inhibiting the formation of solid electrolyte interface (SEI) layers and lithium dendrites on the negative electrode. However, the negative electrode cannot effectively improve and enhance the initial charge and discharge efficiency, specific capacity, and cycle performance of lithium batteries. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and to provide a composite titanium dioxide film and a preparation method thereof, so as to solve the technical problem that the existing titanium dioxide is almost used in a loading manner as a negative electrode material, resulting in unsatisfactory electrochemical properties such as charge and discharge efficiency, specific capacity and cycle.

[0006] Another object of the present invention is to provide an electrode sheet and an application of the electrode sheet to solve the technical problems of existing titanium dioxide-containing electrode sheets having unsatisfactory electrochemical properties such as charge and discharge efficiency, specific capacity, and cycle performance.

[0007] In order to achieve the purpose of the present invention, one aspect of the present invention provides a method for preparing a composite titanium dioxide film. The method for preparing a composite titanium dioxide film comprises the following steps: A titanium dioxide target and an energy density contributing main element target are co-sputtered in an inert atmosphere to grow a composite titanium dioxide film on a substrate.

[0008] Another aspect of the present invention provides a composite titanium dioxide film, which is grown by the composite titanium dioxide film preparation method of the present invention.

[0009] Another aspect of the present invention provides an electrode sheet, which includes a current collector, and a composite titanium dioxide film is bonded to the surface of the current collector, wherein the composite titanium dioxide film is grown on the current collector according to the preparation method of the present invention.

[0010] Another aspect of the present invention provides the use of the electrode sheet of the present invention, which is used in the preparation of lithium-ion batteries or supercapacitors.

[0011] Compared with the prior art, the preparation method of the composite titanium dioxide film of the present invention directly deposits the titanium dioxide target and the energy density contributing main element target by co-sputtering. In this way, the nanoscale energy density contributing main element is embedded in the titanium dioxide matrix, thereby forming a larger surface area in the composite titanium dioxide film for lithium ions to accommodate, giving the composite titanium dioxide film the characteristic of small interface resistance. Moreover, after the composite titanium dioxide film is used as the negative electrode film layer, the titanium dioxide matrix contained therein can effectively prevent the direct contact between the electrolyte and the nanoscale energy density contributing main element, can reduce and prevent the irreversible side reaction between the electrolyte and the energy density contributing main body, reduce the generation of the solid electrolyte membrane (SEI), reduce the stress of the periodic volume change, and maintain the structural stability of the lithium ion embedding / ejection process. In addition, the co-sputtering method is used to grow and form the film layer, and its conditions are easy to control, which effectively ensures that the chemical properties of the grown composite titanium dioxide film are stable, and the composite titanium dioxide film is given good high rate performance, good safety performance, high efficiency, and is suitable for industrial large-scale production.

[0012] Therefore, the composite titanium dioxide film of the present invention has a small interface resistance, and the titanium dioxide matrix contained therein can effectively prevent the direct contact between the electrolyte and the main elements contributing to the nano-scale energy density, reduce and prevent the irreversible side reactions between the electrolyte and the main elements contributing to the energy density, reduce the generation of the solid electrolyte membrane (SEI), and then reduce the stress of the periodic volume change, while maintaining the structural stability during the lithium ion insertion / extraction process.

[0013] The electrode sheet of the present invention is formed by growing a composite titanium dioxide film directly on the current collector using the preparation method of the present invention. Therefore, the electrode sheet has a small internal resistance, and the composite titanium dioxide film contained therein can effectively prevent the direct contact between the electrolyte and the main element contributing to the nano-scale energy density, reduce and prevent the irreversible side reaction between the electrolyte and the main element contributing to the energy density, reduce the generation of the solid electrolyte membrane (SEI), and then reduce the stress of the periodic volume change, while maintaining the structural stability during the lithium ion insertion / extraction process.

[0014] Due to the advantages of the electrode sheet of the present invention, the lithium ion conduction rate of the lithium ion battery containing the electrode sheet of the present invention is high, the structural stability and the capacity retention rate are high, the lithium ion battery is endowed with high initial charge and discharge efficiency and good cycle performance of the lithium ion battery or supercapacitor, the cycle life is extended, and the safety performance is high. The supercapacitor containing the electrode sheet of the present invention has a small internal resistance, fast charge and discharge, and excellent energy storage performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an XRD diagram of the composite titanium dioxide thin film material provided in Example 1 of the present invention; Figure 2 The charge and discharge curves of the lithium ion battery containing the composite titanium dioxide thin film electrode material provided in Example 7 of the present invention at 150 mA / g for the first cycle, the 50th cycle, and the 100th cycle; Figure 3 It is a comparison diagram of the first charge and discharge curves of lithium ion batteries containing composite titanium dioxide thin film electrode materials provided in Examples 8, 9, 10, 11 and 12 of the present invention at 150 mA / g; wherein, curve 1 is the first charge and discharge curve of the lithium ion battery obtained in Example 8, curve 2 is the first charge and discharge curve of the composite titanium dioxide thin film electrode material obtained in Example 9, curve 3 is the first charge and discharge curve of the lithium ion battery obtained in Example 10, curve 4 is the first charge and discharge curve 1 of the lithium ion battery obtained in Example 11, and curve 5 is the first charge and discharge curve of the lithium ion battery obtained in Example 12; Figure 4 This is a cycle performance diagram of a lithium ion battery containing a composite titanium dioxide thin film electrode material obtained in Example 7 of the present invention at 3000 mA / g; Figure 5 This is a diagram of the coulombic efficiency of a lithium-ion battery containing a composite titanium dioxide thin film electrode material at 3000 mA / g obtained in Example 7 of the present invention. DETAILED DESCRIPTION Embodiment 1

[0016] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: Use a copper plate with a diameter of 70 mm as a tray for the powder target, evenly spread the rutile titanium dioxide powder in the tray, and use a 5-ton unidirectional press to perform unidirectional dry pressing to obtain a titanium dioxide powder target; S12: The titanium dioxide powder target prepared in step S11 and a purchased silicon ceramic target with a purity of 99.999% are used as sputtering sources. On a Japanese 304 stainless steel substrate, the distance between the substrate and the target is 50 mm. In a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Si=2:1 is used to prepare a TiO2-Si composite film with a thickness of 1 μm; during deposition, the substrate is maintained at 300°C.

[0017] The composite titanium dioxide film prepared in Example 1 was subjected to XRD analysis, and its XRD pattern is as follows: Figure 1 shown. Embodiment 2

[0018] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: Weigh a certain amount of titanium dioxide powder, add 5% concentration of polyvinyl alcohol and stir until the powder has a certain viscosity, then put the powder into a metal mold, increase the pressure to the design pressure at a pressure increase rate of 50MPa / min and maintain the pressure for a period of time, then release the pressure at a rate of 30MPa / min, and take it out from the metal mold to obtain a blank; put the blank into a muffle furnace, increase the temperature to 600°C at 1°C / min, keep it warm for 5h, then increase the temperature to 950°C at 5°C / min, and keep it warm for 10h, so as to obtain a titanium dioxide ceramic target; S12: The prepared titanium dioxide ceramic target and the purchased nickel ceramic target with a purity of 99.999% were used as sputtering sources. The distance between the substrate and the target was 50 mm. In a mixed atmosphere of high-purity nitrogen and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Ni=4:1 was used to prepare a TiO2-Ni composite film with a thickness of 1 μm. During the deposition, the substrate was kept at 400°C. Embodiment 3

[0019] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: Use a copper plate with a diameter of 70 mm as a tray for the powder target, evenly spread the brookite titanium dioxide powder in the tray, and use a 5-ton unidirectional press to perform unidirectional dry pressing to obtain a titanium dioxide powder target; S12: The prepared titanium dioxide powder target and the purchased tin ceramic target with a purity of 99.999% were used as sputtering sources. The distance between the substrate and the target was 50 mm. In a mixed atmosphere of high-purity ammonia and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Sn=1:4 was used to prepare a TiO2-Sn composite film with a thickness of 1 μm. During the deposition, the substrate was kept at 200°C. Embodiment 4

[0020] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: After mixing rutile and anatase titanium dioxide powders in a molar ratio of 1:1, add 5% polyvinyl alcohol and stir until the powder has a certain viscosity, then put the powder into a metal mold, increase the pressure to the design pressure at a pressure increase rate of 50MPa / min and maintain the pressure for a period of time, then release the pressure at a rate of 30MPa / min, and take it out of the metal mold to obtain a blank. Put the blank into a muffle furnace, increase the temperature to 600℃ at 1℃ / min, keep it warm for 5h, then increase the temperature to 950℃ at 5℃ / min, keep it warm for 10h, and obtain a titanium dioxide ceramic target; S12: The prepared titanium dioxide ceramic target and the purchased manganese ceramic target with a purity of 99.999% were used as sputtering sources. The distance between the substrate and the target was 50 mm. In a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Mn=4:1 was used to prepare a TiO2-Mn composite film with a thickness of 1 μm. During the deposition, the substrate was kept at 300°C. Embodiment 5

[0021] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: Using a copper plate with a diameter of 70 mm as a tray for the powder target, anatase and brookite titanium dioxide powders were mixed in a molar ratio of 1:1, the mixed powders were evenly spread on the tray, and unidirectional dry pressing was performed using a 5-ton unidirectional press to obtain a titanium dioxide powder target; S12: The prepared titanium dioxide powder target and the purchased zinc ceramic target with a purity of 99.999% were used as sputtering sources. The distance between the substrate and the target was 50 mm. In a mixed atmosphere of high-purity nitrogen and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Zn=2:1 was used to prepare a TiO2-Zn composite film with a thickness of 1 μm. During the deposition, the substrate was kept at 500°C. Embodiment 6

[0022] This embodiment 1 provides a composite titanium dioxide film and a preparation method thereof. The composite titanium dioxide film is prepared according to a method comprising the following steps: S11: After mixing the titanium dioxide powders of rutile and brookite at a molar ratio of 1:1, add 5% concentration of polyvinyl alcohol and stir until the powder has a certain viscosity, then put the powder into a metal mold, increase the pressure to the design pressure at a pressure increase rate of 50MPa / min and maintain the pressure for a period of time, then release the pressure at a rate of 30MPa / min, and take it out of the metal mold to obtain a blank. Put the blank into a muffle furnace, increase the temperature to 700℃ at 1℃ / min, keep it warm for 5h, then increase the temperature to 1000℃ at 5℃ / min, keep it warm for 12h, and obtain a titanium dioxide ceramic target; S12: The prepared titanium dioxide ceramic target and the purchased cobalt ceramic target with a purity of 99.999% were used as sputtering sources. The distance between the substrate and the target was 50 mm. In a mixed atmosphere of high-purity ammonia and oxygen at 1.0×10-2 mbar, a co-sputtering method with a power ratio of TiO2:Co=1:2 was used to prepare a TiO2-Co composite film with a thickness of 1 μm. During the deposition, the substrate was kept at 800°C.

[0023] Comparative Example 1 This embodiment 1 provides a titanium dioxide film and a preparation method thereof. The titanium dioxide film is prepared according to a method comprising the following steps: S11: Use a copper plate with a diameter of 70 mm as a tray for the powder target, evenly spread the titanium dioxide powder in the tray, and use a 5-ton unidirectional press to unidirectionally dry press to obtain the titanium dioxide powder target; S12: The prepared titanium dioxide powder target was used as a sputtering source. A TiO2 film with a thickness of 1 μm was prepared by sputtering on a Japanese 304 stainless steel substrate with a substrate-target distance of 50 mm in a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar. During the deposition, the substrate was maintained at 300°C.

[0024] Examples 7 to 12 and Comparative Example 2 The stainless steel substrates containing the composite titanium dioxide film provided in each of the above-mentioned embodiments 1 to 6 are used as negative electrodes, and the stainless steel substrate containing the titanium dioxide film provided in the comparative example 1 is used as negative electrodes, and lithium-ion batteries are assembled according to the following methods: A button cell was assembled in an argon-filled glove box using lithium sheets as thin film electrodes, an electrolyte concentration of 1 mol / L, and a polypropylene microporous membrane as a battery separator.

[0025] Each lithium-ion battery was subjected to the following relevant electrochemical test conditions: the charge and discharge voltage was 0.01V to 3V.

[0026] Relevant electrochemical test results of each lithium-ion battery: The lithium ion battery provided in Example 7 has a first discharge capacity of 1210mah / g and a charge capacity of 1198mah / g at a rate of 150mA / g. Moreover, the charge and discharge curves of the first, 50th, and 100th cycles of the lithium ion battery provided in Example 7 at 150mA / g are as follows: Figure 2 The cycle performance curve at 3000mA / g is shown in Figure 4 As shown, the Coulomb efficiency curve at 3000mA / g is as follows Figure 5 shown.

[0027] The lithium ion battery provided in Example 8 has an initial discharge specific capacity of 1164 mA / g and a discharge specific capacity of 1121 mA / g at a rate of 150 mA / g.

[0028] The lithium ion battery provided in Example 9 has an initial discharge specific capacity of 1140 mA / g and a discharge specific capacity of 1093 mA / g at a rate of 150 mA / g.

[0029] The lithium ion battery provided in Example 10 has an initial discharge specific capacity of 1099 mA / g and a discharge specific capacity of 1065 mA / g at a rate of 150 mA / g.

[0030] The lithium-ion battery provided in Example 11 has an initial discharge specific capacity of 1134 mA / g and a discharge specific capacity of 1096 mA / g at a rate of 150 mA / g.

[0031] The lithium-ion battery provided in Example 12 has an initial discharge specific capacity of 968 mA / g and a discharge specific capacity of 930 mA / g at a rate of 150 mA / g.

[0032] The lithium-ion battery provided in Comparative Example 2 has an initial discharge specific capacity of 330 mA / g and a discharge specific capacity of 289 mA / g at a rate of 150 mA / g.

[0033] In addition, the comparison curves of the first charge and discharge curves of the lithium ion batteries provided in Examples 8 to 12 at 150 mA / g are as follows: Figure 3 shown.

[0034] Comparing the charge and discharge performance of the lithium ion batteries provided in Examples 7 to 12 and the lithium ion batteries provided in Comparative Example 2, it can be seen that the lithium ion batteries containing the composite titanium dioxide thin films provided in Examples 1 to 6 are significantly better than the lithium ion batteries with pure titanium dioxide negative electrodes. Therefore, the electrochemical test results of each lithium ion battery show that the lithium ion battery has high initial charge and discharge efficiency and good cycle performance, and stable charge and discharge performance.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite titanium dioxide film, characterized in that: The steps include: A titanium dioxide target and an energy density contributing main element target are co-sputtered in an inert atmosphere to grow a composite titanium dioxide film on a substrate.

2. The preparation method according to claim 1, characterized in that: The energy density contributing main element target material includes at least one single target or alloy target of silicon, nickel, cobalt, manganese, zinc, tin, vanadium, gold, silver, copper, and molybdenum, or at least one compound target of silicon, nickel, cobalt, manganese, zinc, tin, vanadium, gold, silver, copper, and molybdenum; and / or The sputtering power of the co-sputtering process satisfies that the ratio of the power of sputtering the titanium dioxide target material to the power of the main element target material contributing to the sputtering energy density is 4:1 to 1:

4.

3. The preparation method according to claim 1, characterized in that: During the co-sputtering process, the temperature of the substrate is controlled to be 200° C.-800° C.; and / or The sputtering atmosphere is a mixed gas atmosphere of at least one of nitrogen, argon, and ammonia and oxygen.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The titanium dioxide target is prepared according to the following method: The titanium dioxide powder is mixed with the organic binder in proportion, and then the pressure is increased to the design pressure at a pressure increase rate of 40-60MPa / min for molding, and then the pressure is released at a rate of 10-30MPa / min to obtain a green blank; the green blank is first heated to 600-800°C at a rate of 1-5°C / min, and kept warm for 3-6h; and then heated to 800-1200°C at a rate of 1-5°C / min for sintering; and / or Laying titanium dioxide powder on the surface of a conductive tray, and then dry-pressing the titanium dioxide powder to obtain a titanium dioxide powder target; and / or The titanium dioxide target material is at least one of rutile, anatase, brookite, and amorphous titanium dioxide, or at least one of titanium monoxide, titanium trioxide, or titanium dioxide trioxide.

5. The preparation method according to claim 4, characterized in that: The dry pressing treatment is to directly apply pressure to the titanium dioxide powder using a 5-ton unidirectional pressure.

6. The preparation method according to any one of claims 1 to 3 and 5, characterized in that: The substrate is a negative electrode current collector of a chemical power source.

7. A composite titanium dioxide film, characterized in that: The composite titanium dioxide film is grown and formed according to the preparation method described in any one of claims 1-6.

8. An electrode sheet, comprising a current collector, characterized in that: A composite titanium dioxide film is also combined on the surface of the current collector, and the composite titanium dioxide film is grown on the current collector according to the preparation method according to any one of claims 1 to 5.

9. The electrode sheet according to claim 8, characterized in that: The thickness of the composite titanium dioxide film is 0.1-10 μm.

10. Use of the electrode sheet according to claim 8 or 9 in a lithium ion battery or a supercapacitor.

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