Composite manganese oxide film as well as preparation method and application thereof

Abstract

The invention provides a composite manganese oxide film as well as a preparation method and application thereof. The preparation method of the composite manganese oxide film comprises the following steps: co-sputtering a manganese oxide target material and an energy density contribution main body element target material in an inert atmosphere, and growing the composite manganese oxide film on a substrate. According to the preparation method of the composite manganese oxide thin film, a manganese oxide 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 manganese oxide thin film. According to the invention, the growth of the composite manganese oxide thin film is realized, so that the grown composite manganese oxide thin film has the characteristics of small interface resistance and large specific surface area, the generation of solid electrolyte membranes (SEI) can be reduced, the stress of periodic volume change is reduced, and the structural stability in the lithium ion intercalation / deintercalation process is maintained. In addition, the preparation method effectively ensures that the grown composite manganese oxide 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 manganese oxide compound film and a preparation method and application thereof. Background Art

[0002] 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 the electrode material directly determines the performance of the lithium-ion battery.

[0003] Manganese oxide compounds such as manganese dioxide and lithium manganate have long been used as positive electrode materials due to their good electrochemical properties. For example, manganese dioxide has the advantages of high theoretical specific capacitance and energy density, abundant resources, low price and environmental friendliness. Moreover, the electrode made of manganese dioxide mainly follows the energy storage mechanism of Faraday pseudocapacitance, which achieves energy storage and release through highly reversible chemical adsorption and desorption or redox reaction within a certain potential on the electrode surface and around the electrolyte liquid surface. Therefore, it is considered to be a very promising electrode material. Lithium manganate has the advantages of low raw material cost, abundant sources, high ionic conductivity and electronic conductivity, high power density, good thermal stability, excellent room temperature rate performance and environmental friendliness. It is regarded as one of the most promising positive electrode materials and has received extensive attention from researchers.

[0004] However, in actual applications, it was found that these manganese oxide compounds also have certain defects, such as low electronic conductivity, small specific surface area, poor cycle stability, etc. Lithium manganese oxide has a low capacity during use, which limits its commercial application.

[0005] In order to solve the above-mentioned shortcomings of manganese oxide compounds, the structure and performance of lithium manganate are currently improved mainly through bulk doping and surface coating, which invisibly increases the cost of manganese oxide compounds. In addition, most manganese oxide compounds are prepared by first preparing a positive electrode slurry with a conductive agent and a binder, and then coating to obtain a positive electrode sheet. It is precisely because of the presence of the binder that the internal resistance of the corresponding positive electrode sheet prepared is relatively large, and the active layer containing manganese oxide compounds has fallen off, resulting in the initial charge and discharge efficiency and specific capacity of the lithium battery and the cycle performance is not ideal, which needs to be improved. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and to provide a composite manganese oxide compound film and a preparation method thereof, so as to solve the technical problems that the existing manganese oxide compound has high cost and the active layer is formed by coating, resulting in unsatisfactory electrochemical properties such as charge and discharge efficiency and specific capacity of the formed positive electrode sheet and cycle.

[0007] Another object of the present invention is to provide an electrode sheet and an application of the electrode sheet to solve the technical problems that the existing electrode sheets containing manganese oxides have unsatisfactory electrochemical properties such as charge and discharge efficiency, specific capacity and cycle performance.

[0008] In order to achieve the purpose of the present invention, one aspect of the present invention provides a method for preparing a composite manganese oxide compound thin film. The method for preparing a composite manganese oxide compound thin film comprises the following steps: A manganese oxide target and an energy density contributing main element target are co-sputtered in an inert atmosphere to grow a composite manganese oxide film on a substrate.

[0009] Another aspect of the present invention provides a composite manganese oxide compound thin film, which is grown by the composite manganese oxide compound thin film preparation method of the present invention.

[0010] Another aspect of the present invention provides an electrode sheet, which includes a current collector, and a composite manganese oxide film is bonded to the surface of the current collector, wherein the composite manganese oxide film is grown on the current collector according to the preparation method of the present invention.

[0011] 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.

[0012] Compared with the prior art, the preparation method of the composite manganese oxide film of the present invention directly deposits the manganese oxide 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 manganese oxide matrix, thereby forming a larger surface area in the composite manganese oxide film for lithium ions to accommodate, giving the composite manganese oxide film the characteristic of small interface resistance, and increasing the specific surface area of ​​the material. Moreover, after the composite manganese oxide film is used as the negative electrode film layer, the manganese oxide matrix contained therein can effectively prevent the electrolyte from directly contacting the nanoscale energy density contributing main element, can reduce and prevent the irreversible side reaction between the electrolyte and the energy density contributing main element, reduce the generation of solid electrolyte membrane (SEI), reduce the stress of periodic volume change, maintain the structural stability during the lithium ion insertion / extraction process, and give the composite film material good high rate performance and good safety performance. In addition, the film layer is grown by co-sputtering method, and its conditions are easy to control, which effectively ensures that the chemical properties of the grown composite manganese oxide compound film are stable and efficient, and is suitable for large-scale industrial production.

[0013] The electrode sheet of the present invention is formed by growing a composite manganese oxide 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 manganese oxide 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), reduce the stress of the periodic volume change, and maintain the structural stability during the lithium ion insertion / extraction process. It also has a large rate performance and good safety performance.

[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 the lithium ion battery or supercapacitor has high rate performance, good safety performance, good cycle performance, extended cycle life, and high safety performance. The supercapacitor containing the electrode sheet of the present invention has low 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 manganese oxide 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 manganese oxide compound thin film electrode material provided in Example 7 of the present invention at 150 mA / g for the first cycle, the 30th cycle, and the 100th cycle; Figure 3 It is a comparison diagram of the first charge and discharge curves of lithium ion batteries of composite manganese oxide 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 lithium ion battery 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 manganese oxide thin film electrode material obtained in Example 7 of the present invention at 3000 mA / g; Figure 5 This is a coulombic efficiency diagram of a lithium-ion battery containing a composite manganese oxide thin film electrode material obtained in Example 7 of the present invention at 3000 mA / g; DETAILED DESCRIPTION Embodiment 1

[0016] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound 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 manganese dioxide powder in the tray, and use a 5-ton unidirectional press to unidirectionally dry press to obtain a manganese dioxide powder target; S12: The manganese 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 substrate-target distance is 50 mm. In a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar, a MnO2-Si composite film with a thickness of 1 μm is prepared by a co-sputtering method with a power ratio of MnO2:Si=2:1. During the deposition, the substrate is kept at 300°C. The composite manganese oxide film prepared in Example 1 was subjected to XRD analysis, and its XRD pattern is shown in FIG. Figure 1 shown. Embodiment 2

[0017] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound film is prepared according to a method comprising the following steps: S11: Weigh a certain amount of manganese monoxide 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 manganese monoxide ceramic target; S12: The manganese monoxide ceramic target prepared in step S11 and the purchased nickel ceramic target with a purity of 99.999% are used as sputtering sources on a Japanese 304 stainless steel substrate with a substrate-target distance of 50 mm in a high-purity nitrogen and oxygen atmosphere of 1.0×10-2 mbar. A MnO-Ni composite thin film with a thickness of 1 μm was prepared by co-sputtering in a mixed atmosphere of MnO:Ni=4:1 power ratio in a mixed atmosphere of MnO:Ni=4:1; during the deposition, the substrate was kept at 400°C. Embodiment 3

[0018] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound 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 manganese trioxide powder in the tray, and use a 5-ton unidirectional press to perform unidirectional dry pressing to obtain the manganese trioxide powder target; S12: The manganese trioxide powder target prepared in step S11 and a purchased tin ceramic target with a purity of 99.999% are used as sputtering sources. On a Japanese 304 stainless steel substrate, the substrate-target distance is 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 Mn2O3:Sn=1:4 is used to prepare a Mn2O3-Sn composite film with a thickness of 1 μm; during deposition, the substrate is maintained at 200°C. Embodiment 4

[0019] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound film is prepared according to a method comprising the following steps: S11: Weigh a certain amount of lithium manganate 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 lithium manganate ceramic target; S12: The lithium manganese oxide ceramic target prepared in step S11 and the purchased titanium ceramic target with a purity of 99.999% are used as sputtering sources. On a Japanese 304 stainless steel substrate, the substrate-target distance is 50 mm. In a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar, a LiMn2O4-Ti composite film with a thickness of 1 μm is prepared by co-sputtering with a power ratio of LiMn2O4-Ti=4:1; during deposition, the substrate is maintained at 300°C. Embodiment 5

[0020] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound 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 lithium permanganate powder in the tray, and use a 5-ton unidirectional press to unidirectionally dry press to obtain the lithium permanganate powder target; S12: The lithium permanganate powder target prepared in step S11 and the purchased zinc ceramic target with a purity of 99.999% are used as sputtering sources. On a Japanese 304 stainless steel substrate, the substrate-target distance is 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 is used to prepare a TiO2-Zn composite film with a thickness of 1 μm; during deposition, the substrate is maintained at 500°C. Embodiment 6

[0021] This embodiment 1 provides a composite manganese oxide compound film and a preparation method thereof. The composite manganese oxide compound 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 sprinkle the mixed powder of manganese dioxide and lithium manganate on the tray, and use a 5-ton unidirectional press to perform unidirectional dry pressing to obtain a manganese dioxide / lithium manganate powder target; S12: The manganese dioxide / lithium manganate powder target prepared in step S11 and a purchased cobalt ceramic target with a purity of 99.999% are used as sputtering sources. On a Japanese 304 stainless steel substrate, the substrate-target distance is 60 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 (MnO2 / LMO):Co=1:2 is used to prepare a (MnO2 / LMO)-Co composite film with a thickness of 1 μm; during deposition, the substrate is maintained at 700°C.

[0022] Comparative Example 1 This embodiment 1 provides a manganese oxide compound film and a preparation method thereof. The manganese oxide compound 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 sprinkle the mixed powder of manganese dioxide and lithium manganate on the tray, and use a 5-ton unidirectional press to perform unidirectional dry pressing to obtain a manganese dioxide / lithium manganate powder target; S12: The prepared manganese dioxide / lithium manganate powder target was used as a sputtering source. On a Japanese 304 stainless steel substrate, the substrate-target distance was 40 mm. In a mixed atmosphere of high-purity argon and oxygen at 1.0×10-2 mbar, a MnO2 / LMO film with a thickness of 1 μm was sputtered. During the deposition, the substrate was maintained at 300°C.

[0023] Examples 6 to 12 and Comparative Example 2 The stainless steel substrate containing the composite manganese oxide film provided in each of the above-mentioned embodiments 1 to 6 is used as the positive electrode, and the stainless steel substrate containing the MnO2 / LMO film provided in the comparative example 1 is used as the positive electrode, 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.

[0024] Each lithium-ion battery was subjected to the following relevant electrochemical test conditions: the charge and discharge voltage was 0.01V to 3V.

[0025] Relevant electrochemical test results of each lithium-ion battery: The lithium ion battery provided in Example 7 has a first discharge capacity of 1330mah / g and a charge capacity of 1288mah / g at a rate of 150mA / g. The charge and discharge curves of the lithium ion battery provided in Example 7 at 150mA / g for the first cycle, the 30th cycle, and the 100th cycle 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.

[0026] The lithium ion battery provided in Example 8 has an initial discharge specific capacity of 988 mA / g and a discharge specific capacity of 952 mA / g at a rate of 150 mA / g.

[0027] The lithium ion battery provided in Example 9 has an initial discharge specific capacity of 1039 mAh / g and a discharge specific capacity of 1007 mAh / g at a rate of 150 mA / g.

[0028] The lithium ion battery provided in Example 10 has an initial discharge capacity of 1033 mA / g and a discharge capacity of 999 mA / g at a rate of 150 mA / g.

[0029] The lithium-ion battery provided in Example 11 has an initial discharge specific capacity of 932 mAh / g and a discharge specific capacity of 912 mAh / g at a rate of 150 mAh / g.

[0030] The lithium-ion battery provided in Example 12 has an initial discharge specific capacity of 1148 mA / g and a discharge specific capacity of 885 mA / g at a rate of 150 mA / g.

[0031] The lithium-ion battery provided in Comparative Example 2 has an initial discharge specific capacity of 210 mA / g and a discharge specific capacity of 199 mA / g at a rate of 150 mA / g.

[0032] 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.

[0033] 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 manganese oxide film provided in Examples 1 to 6 are significantly better than the lithium-ion batteries with simple manganese oxide electrodes. The battery has high initial charge and discharge efficiency and good cycle performance, and the charge and discharge performance is stable.

[0034] 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 manganese oxide film, It is characterized in that The steps include: A manganese oxide target and an energy density contributing main element target are co-sputtered in an inert atmosphere to grow a composite manganese oxide film on a substrate.

2. The preparation method according to claim 1, Features: The energy density contributing main element target material includes at least one single target or alloy target of silicon, tin, titanium, vanadium, aluminum, gold, silver, copper, molybdenum, and cobalt, or at least one compound target of silicon, tin, titanium, vanadium, aluminum, gold, silver, copper, molybdenum, and cobalt; and / or The sputtering power of the co-sputtering process satisfies that the ratio of the power of sputtering the manganese oxide 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, Features: During the co-sputtering process, the temperature of the substrate is controlled to be 200° C.-700° 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, Features: The manganese oxide target is prepared according to the following method: The manganese oxide compound is mixed with an organic binder in proportion, and then the pressure is increased to the design pressure at a pressure increase rate of 40-60 MPa / min for molding, and then the pressure is released at a rate of 10-30 MPa / 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 3-6 hours; and then heated to 800-1200°C at a rate of 1-5°C / min for sintering; and / or Laying the manganese oxide compound powder on the surface of the substrate, and then dry pressing the manganese oxide compound powder; and / or The manganese oxide target material is at least one of manganese monoxide, manganese dioxide, manganese trioxide, lithium manganate, lithium permanganate, and lithium-rich lithium manganate.

5. The preparation method according to claim 4, Features: The dry pressing treatment is to directly apply pressure to the manganese oxide compound powder using a 5-ton unidirectional pressure.

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

7. A composite manganese oxide film, Features: The composite manganese oxide film is grown according to the preparation method according to any one of claims 1-6.

8. An electrode sheet comprising a current collector, Features: A composite manganese oxide film is also combined on the surface of the current collector. The composite manganese oxide 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, Features: The thickness of the composite manganese oxide 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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