Nanometer multilayer structure Mo2N-BN nitride film and preparation method and application thereof

Abstract

The invention relates to a nano multilayer structure Mo2N-BN nitride thin film and a preparation method and application thereof, and relates to the technical field of thin film materials and surface science, and the thin film is prepared by preparing a face-centered cubic structure Mo2N thin film on a substrate through a pulse multi-arc ion plating technology in a nitrogen atmosphere and under a heating condition. And preparing the hexagonal BN film by a radio frequency magnetron sputtering technology. The thin film prepared by the method has the characteristics of high film-substrate bonding strength, high hardness, high electronic impedance and good wettability, can well improve the interface problem of metal lithium / solid electrolyte, improves the transmission kinetics of lithium ions at the interface and inhibits the growth of lithium dendrites, and has a relatively good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thin film materials and surface science, and particularly relates to a nano-multilayer structure Mo2N-BN nitride film and a preparation method and application thereof. BACKGROUND

[0002] All-solid-state lithium metal batteries have outstanding advantages such as high safety and high energy density, and are considered as one of the important development directions of next-generation power and energy storage battery technologies. In all-solid-state lithium metal batteries, lithium metal is used as a negative electrode material, and its main function is to provide lithium ions. During the discharge process, lithium metal loses electrons, and lithium ions are transported to the positive electrode through the solid electrolyte, and the process is reversed during the charging process. The interface problem between the metal lithium / solid electrolyte, such as high interface impedance and lithium dendrite, has seriously limited the development of all-solid-state lithium metal batteries. How to solve the interface problem between the metal lithium / solid electrolyte, improve the transport dynamics of lithium ions at the interface, and inhibit the growth of lithium dendrites is a problem that needs to be solved in the field of all-solid-state batteries.

[0003] From the microscopic mechanism, the high interface impedance is mainly due to the poor wettability of lithium on the surface of the solid electrolyte, and the ideal face / face contact between the metal lithium and the solid electrolyte becomes an actual point / face contact, which leads to a small effective contact area and an increase in overall impedance. In addition, the weak electronic conductivity in the solid electrolyte is another reason for the growth of lithium dendrites, which can lead to the direct precipitation and growth of lithium dendrites from the inside of the solid electrolyte.

[0004] The surface composite film of the solid electrolyte can improve the transport dynamics of lithium ions at the interface and inhibit the growth of lithium dendrites, but the film-base bonding strength is not high, and the performance of the thin film is not good, which leads to the fact that the interface problem between the metal lithium / solid electrolyte cannot be further effectively solved. Therefore, the present application provides a nano-multilayer structure Mo2N-BN nitride film and a preparation method and application thereof. SUMMARY

[0005] The present application is aimed at the above-mentioned problems, and provides a nano-multilayer structure Mo2N-BN nitride film and a preparation method and application thereof.

[0006] The present application achieves the above-mentioned purposes through the following technical solutions: As a first aspect of the present application, the present application provides a nano-multilayer structure Mo2N-BN nitride film, which is obtained by sequentially preparing a face-centered cubic structure Mo2N film on a substrate using a pulse multi-arc ion plating technology and preparing a hexagonal BN film using a radio frequency magnetron sputtering technology under the conditions of a nitrogen atmosphere and heating.

[0007] As a further optimization scheme, the nanometer multilayer structure Mo2N-BN nitride film is composed of face-centered cubic structure Mo2N film and hexagonal BN film alternately, and the thickness ratio of the single layer of the face-centered cubic structure Mo2N film and the hexagonal BN film is 1-4:2-6.

[0008] As a second aspect of the present application, the present application also provides a preparation method of the nanometer multilayer structure Mo2N-BN nitride film as described in any of the above, specifically comprising the following steps: The substrate is installed on the sample table of the magnetron-multiple-arc composite film coating machine, the metal molybdenum target is installed on the multiple-arc ion plating cathode, the boron nitride target is installed on the magnetron sputtering cathode, and the distance between the metal molybdenum target, the boron nitride target and the substrate is adjusted; The machine is started to vacuumize, the substrate is heated, argon is introduced, the working pressure is set, and the substrate, the metal molybdenum target and the boron nitride target are respectively sputter cleaned; Nitrogen is introduced, the nitrogen flow is set to 40-100 sccm, the working gas pressure is controlled to be 0.5-1.0 Pa, the sample table rotation speed is controlled to be 5-30 rpm, the bias voltage is set to be-200 V, the multiple-arc target sputtering current is 100-150 A, the face-centered cubic structure Mo2N film is prepared, the magnetron target sputtering voltage is set to be 300-600 V, and the hexagonal B-N film is prepared; The film deposition time is 30-90 min, and after the deposition is completed, the obtained film is subjected to cooling treatment.

[0009] As a further optimization scheme, in the step (1), the distance between the metal molybdenum target, the boron nitride target and the substrate is respectively 80 mm and 120 mm.

[0010] As a further optimization scheme, in the step (2), the vacuumization is to 8×10 -4 Pa, the substrate is heated to 300-500℃, the argon flow is set to be 60-90 sccm, and the working pressure is controlled to be 1.0-1.5 Pa.

[0011] As a further optimization scheme, the step (3) is specifically: the sputtering bias voltage is set to be 500-1000 V, the sputtering time is 10 min, the substrate is sputter cleaned, the multiple-arc target sputtering current is set to be 70-120 A, the magnetron target pulse sputtering power is 90-120 W, the sputtering time is controlled to be 5-10 min, and the metal molybdenum target and the boron nitride target are sputter cleaned.

[0012] As a further optimization scheme, in the step (4), the cooling treatment is to cool the obtained film to below 100℃ under vacuumization, and then to cool to room temperature under natural vacuum.

[0013] As a third aspect of the present application, the present application also provides an application of the nano-multilayer structure Mo2N-BN nitride film as described in any of the above in the preparation of a solid-state electrolyte.

[0014] As a fourth aspect of the present application, the present application also provides a thin film composite solid-state electrolyte comprising the nano-multilayer structure Mo2N-BN nitride film as described in any of the above, and the substrate is a solid-state electrolyte.

[0015] As a further optimization, the solid-state electrolyte is lithium lanthanum zirconium tantalum oxide.

[0016] The present application has the following beneficial effects: The present application uses a method combining pulsed multi-arc ion plating and radio frequency magnetron sputtering to prepare a nano-multilayer structure Mo2N-BN nitride film composed of face-centered cubic molybdenum nitride (fcc-Mo2N) and hexagonal boron nitride (h-BN), uses the good wettability of Mo-N and Li to improve the interface contact between Li and the solid-state electrolyte, uses the electronic insulation of h-BN and the ultra-high elastic modulus generated by the fcc-Mo2N / h-BN nano-multilayer structure to inhibit the generation of lithium dendrites, and uses the high ionization rate of the multi-arc ion plating technology to improve the bonding strength between the film and the substrate. The prepared film has a high film-substrate bonding strength of 50-80 N, a high hardness of 36-45 GPa, a high electronic impedance (10 4 -10 5 Ω·cm), good wettability (wetting angle about 12 degrees), and makes the solid-state electrolyte have a more optimal cycle number. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural characterization of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 1 of the present application (in the figure, (a) is a cross-sectional TEM image; (b) is a surface SEM morphology); Figure 2 is a hardness comparison of the nano-multilayer structure Mo2N-BN nitride films prepared in Examples 1-3 of the present application with different thickness ratios; Figure 3 is a film-substrate bonding strength comparison of the nano-multilayer structure Mo2N-BN nitride films prepared in Examples 1-3 of the present application with different thickness ratios; Figure 4 is a comparison of the battery application experimental results of the nano-multilayer structure Mo2N-BN nitride films prepared in Examples 1-3 of the present application with different thickness ratios. DETAILED DESCRIPTION

[0018] The application will be further described in conjunction with the accompanying drawings. It is necessary to point out here that the following specific embodiments are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0019] The method used in the application is a conventional method known to those skilled in the art, and if no specific conditions are indicated, it is carried out according to conventional conditions or the conditions recommended by the manufacturer. If no manufacturer of the materials or instruments is indicated, they are all products that can be obtained by market purchase.

[0020] In the following examples, the solid electrolyte used is tantalum-doped lithium lanthanum zirconium oxide (LLZTO), but the application is not limited thereto.

[0021] Example 1 The nanometer multilayer structure Mo2N-BN nitride film provided in the present embodiment is prepared by a method combining pulse multi-arc ion plating and radio frequency magnetron sputtering, and the specific steps include: Cut the LLZTO into a Φ10×1 mm wafer to obtain a substrate, and load the substrate into a magnetron-multi-arc composite film plating machine; Install the Mo target on the multi-arc ion plating cathode, and adjust the distance between the Mo target and the substrate to 80 mm; Install the BN target on the magnetron sputtering cathode, and adjust the distance between the BN target and the substrate to 120 mm; Turn on the machine, first vacuumize to 8×10 -4 Pa, and then heat the substrate to 300-500℃, preferably 350℃ in the present embodiment; Introduce argon gas, and set the argon gas flow rate to 60-90 sccm to control the working pressure to 1.0 Pa; Turn on the pulse bias power supply, and set the sputtering bias to 500-1000V, preferably 500V in the present embodiment, and the sputtering time to 10 min to perform sputtering cleaning on the substrate; Turn on the sputtering power supply, and set the multi-arc target sputtering current to 70-120A, preferably 70A in the present embodiment, and the magnetron target pulse sputtering power to 90-120W, preferably 120W in the present embodiment, and control the sputtering time to 8 min to perform sputtering cleaning on the Mo target and the BN target; Turning off other sputtering power, nitrogen gas is introduced, the nitrogen gas flow is set to 40-100 sccm, preferably 50 sccm in this embodiment, the working pressure is controlled to 0.5-1.0 Pa, preferably 1.0 Pa in this embodiment, the bias power, multi-arc target sputtering power and magnetron sputtering power are turned on, the bias voltage is set to -200 V, the multi-arc target sputtering current is set to 70 A, the face-centered cubic structure Mo2N film is prepared, the magnetron sputtering voltage is set to 300-600 V, preferably 300 V in this embodiment, the hexagonal BN film is prepared, and the film deposition time is 30-90 min, preferably 30 min in this embodiment; The rotation speed of the sample table is controlled to 10 rpm; After sputtering, the sputtering and heating power are turned off, the aeration is stopped, the obtained sample is cooled to below 100℃ under the condition of vacuum pumping by a molecular pump, the molecular pump is turned off, the power is turned off, and the sample is taken out after natural cooling to room temperature, thereby preparing the nano-multilayer structure Mo2N-BN nitride film on the solid electrolyte LLZTO.

[0022] The nano-multilayer structure Mo2N-BN nitride film obtained in Example 1 is characterized.

[0023] Figure 1 (a) is a cross-sectional TEM image of the nano-multilayer structure Mo2N-BN nitride film, it can be seen that the film presents a multilayer structure, the total thickness is 100 nm, and the thickness ratio of the single-layer Mo2N film to the BN film is 4 nm / 6 nm.

[0024] Figure 1 (b) is a surface SEM morphology image of the nano-multilayer structure Mo2N-BN nitride film.

[0025] Example 2 The nano-multilayer structure Mo2N-BN nitride film provided in this embodiment is prepared by a method combining pulsed multi-arc ion plating and radio frequency magnetron sputtering, and the specific steps include: The LLZTO is cut into a Φ10×1 mm wafer to obtain a substrate, and the substrate is loaded into a magnetron-multi-arc composite plating film machine; The Mo target is installed on the multi-arc ion plating cathode, and the distance between the Mo target and the substrate is adjusted to 80 mm; The BN target is installed on the magnetron sputtering cathode, and the distance between the BN target and the substrate is adjusted to 120 mm; The machine is started, and the vacuum is first pumped to 8×10 -4 Pa, and then the substrate is heated to 350℃; Argon gas is introduced, the argon gas flow is set to 60-90 sccm, and the working pressure is controlled to 1.0 Pa; Turn on the pulse bias power supply, set the sputtering bias to 500 V, and sputter for 10 min to clean the substrate; Turn on the sputtering power supply, set the multi-arc target sputtering current to 70 A, the magnetron target pulse sputtering power to 120 W, and control the sputtering time to 8 min to sputter clean the Mo target and BN target; Turn off other sputtering power supplies, introduce nitrogen gas, set the nitrogen gas flow to 50 sccm, control the working pressure to 1.0 Pa, turn on the bias power supply, multi-arc target sputtering power supply, and magnetron target sputtering power supply; set the bias to -200 V, the multi-arc target sputtering current to 70 A, prepare a face-centered cubic structure Mo2N thin film, set the magnetron target sputtering voltage to 300 V, prepare a hexagonal B-N thin film, and the thin film deposition time is 30 min; Control the rotation speed of the sample stage to be 20 rpm; After sputtering, turn off the sputtering and heating power supplies, stop the gas supply, and cool the obtained sample to below 100 ℃ under vacuum pumping, turn off the molecular pump and power supply, and cool to room temperature under natural vacuum, then take out the sample, i.e. a nano-multilayer structure Mo2N-BN nitride thin film is prepared on the solid electrolyte LLZTO, and structure characterization shows that the thickness ratio of the single-layer Mo2N thin film to the BN thin film is 2 nm / 3 nm.

[0026] Example 3 The nano-multilayer structure Mo2N-BN nitride thin film provided by the present embodiment is prepared by a method combining pulse multi-arc ion plating and radio frequency magnetron sputtering, and the specific steps include: Cut the LLZTO into Φ10*1 mm round pieces and load them into a magnetron-multi-arc composite plating film machine; Install the Mo target on the multi-arc ion plating cathode, and adjust the distance between the Mo target and the substrate to 80 mm; Install the BN target on the magnetron sputtering cathode, and adjust the distance between the BN target and the substrate to 120 mm; Turn on the machine, first pump to 8*10 -4 Pa, then heat the substrate to 350 ℃; Introduce argon gas, set the argon gas flow to 60-90 sccm, and control the working pressure to 1.0 Pa; Turn on the pulse bias power supply, set the sputtering bias to 500 V, and sputter for 10 min to clean the substrate; Turn on the sputtering power supply, set the multi-arc target sputtering current to 70 A, the magnetron target pulse sputtering power to 120 W, and control the sputtering time to 8 min to sputter clean the Mo target and BN target; Turning off other sputtering power, nitrogen is introduced, the nitrogen flow is set to 50 sccm, the working pressure is controlled to 1.0 Pa, the bias power, multi-arc target sputtering power and magnetron sputtering power are turned on, the bias voltage is set to -200 V, the multi-arc target sputtering current is set to 70 A, the face-centered cubic structure Mo2N film is prepared, the magnetron sputtering voltage is set to 300 V, and the hexagonal B-N film is prepared; the film deposition time is 30 min; The rotation speed of the sample table is controlled to 30 rpm; After sputtering, the sputtering and heating power are turned off, the aeration is stopped, the obtained sample is cooled to below 100 DEG C under the condition of vacuum pumping by a molecular pump, the molecular pump is turned off, the power is turned off, and the sample is taken out after being cooled to room temperature under natural vacuum, thereby the nano-multilayer structure Mo2N-BN nitride film is prepared on the solid electrolyte LLZTO, and the structure characterization shows that the thickness ratio of the Mo2N film to the BN film is 1 nm / 2 nm.

[0027] Firstly, the nano-multilayer structure Mo2N-BN nitride film prepared in Examples 1 to 3 is subjected to performance tests of the bonding strength with the solid electrolyte LLZTO and the film hardness in sequence.

[0028] The results are shown in Table 1. Figures 2-3 As shown in Table 1, the bonding strength of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 1 with the solid electrolyte LLZTO is 69 N, the film hardness is 39 GPa, the bonding strength of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 2 with the solid electrolyte LLZTO is 74 N, the hardness is 41 GPa, and the bonding strength of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 3 with the solid electrolyte LLZTO is 78 N, the hardness is 45 GPa.

[0029] Secondly, the nano-multilayer structure Mo2N-BN nitride film prepared in Examples 1 to 3 is subjected to performance tests of the electronic resistivity and the wettability in sequence. The results show that the nano-multilayer structure Mo2N-BN nitride films prepared in Examples 1 to 3 all have high impedance and good wettability, the electronic resistivity of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 1 is 2 x 10 4 Ω·cm, the wettability angle is 12 degrees, the electronic resistivity of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 2 is 8 x 10 4 Ω·cm, the wettability angle is 12 degrees, and the electronic resistivity of the nano-multilayer structure Mo2N-BN nitride film prepared in Example 3 is 4 x 10 5 Ω·cm, the wettability angle is 12 degrees.

[0030] Finally, the nanolaminate Mo2N-BN nitride thin film prepared in Example 1-3 and the solid electrolyte LLZTO were assembled into a symmetric simulation battery with lithium metal pieces in a glove box, and the charge-discharge cycle test was carried out at 50 ℃ and 50 μA / cm 2 , and the cycle number of the solid electrolyte was obtained. In addition, the solid electrolyte LLZTO without the nanolaminate Mo2N-BN nitride thin film was used as a control group.

[0031] Compared with the control group, it can be seen from Examples 1-3 that after the nanolaminate Mo2N-BN nitride thin film is deposited on the solid electrolyte, the solid electrolyte has a better cycle number (N) Figure 4 ).

[0032] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A nano-multilayered Mo2N-BN nitride thin film, characterized in that, The thin film is prepared by sequentially preparing face-centered cubic structure Mo2N thin film by using pulse multi-arc ion plating technology and preparing hexagonal BN thin film by using radio frequency magnetron sputtering technology under the conditions of nitrogen atmosphere and heating on a substrate.

2. The nanomultilayer Mo2N-BN nitride film according to claim 1, characterized in that, The nano-multilayer structure Mo2N-BN nitride thin film is formed by alternately combining the face-centered cubic structure Mo2N thin film and the hexagonal BN thin film, and the thickness ratio of the single layer of the face-centered cubic structure Mo2N thin film to the hexagonal BN thin film is 1-4:2-6.

3. A method for preparing nanomultilayer Mo2N-BN nitride thin films according to any one of claims 1-2, characterized by, Specifically, the method comprises the following steps: The substrate is installed on a sample table of a magnetron-multi-arc combined film plating machine, a metal molybdenum target is installed on a multi-arc ion plating cathode, a boron nitride target is installed on a magnetron sputtering cathode, and the distances between the metal molybdenum target, the boron nitride target and the substrate are adjusted; The machine is started to perform vacuum pumping, the substrate is heated, argon is introduced, the working pressure is set, and the substrate, the metal molybdenum target and the boron nitride target are respectively subjected to sputter cleaning; Nitrogen is introduced, the nitrogen flow is set to 40-100 sccm, the working gas pressure is controlled to be 0.5-1.0 Pa, the sample table rotation speed is controlled to be 5-30 rpm, the bias voltage is set to be-200 V, the multi-arc target sputtering current is 100-150 A, the face-centered cubic structure Mo2N thin film is prepared, the magnetron target sputtering voltage is set to be 300-600 V, and the hexagonal B-N thin film is prepared; The film deposition time is 30-90 min, and after the deposition is completed, the obtained thin film is subjected to cooling treatment.

4. The method according to claim 3, wherein the method is characterized by, In the step (1), the distances between the metal molybdenum target, the boron nitride target and the substrate are respectively 80 mm and 120 mm.

5. The method according to claim 3, wherein the method is characterized by, In the step (2), vacuum is drawn to 8x10 -4 Pa, the substrate is heated to 300-500 ℃, argon flow is set to 60-90 sccm, and working pressure is controlled to 1.0-1.5 Pa.

6. The method according to claim 3, wherein the method is characterized by, In the step (3), the sputter bias voltage is set to be 500-1000 V, the sputter time is 10 min, the substrate is subjected to sputter cleaning, the multi-arc target sputtering current is set to be 70-120 A, the magnetron target pulse sputtering power is 90-120 W, and the sputter time is controlled to be 5-10 min, and the metal molybdenum target and the boron nitride target are subjected to sputter cleaning.

7. The method according to claim 3, wherein the method is characterized by, In the step (4), the cooling treatment is to cool the obtained thin film to below 100 ℃ under vacuum pumping, and then cool to room temperature under natural vacuum.

8. Application of the nano-multilayer structure Mo2N-BN nitride thin film in the preparation of a solid-state electrolyte.

9. A thin film composite solid state electrolyte characterized by, The nano-multilayer structure Mo2N-BN nitride thin film according to any one of claims 1-2 is included, and the substrate is a solid-state electrolyte.

10. The thin film composite solid state electrolyte of claim 9, wherein, The solid-state electrolyte is lithium lanthanum zirconium tantalum oxide. The solid-state electrolyte is lithium lanthanum zirconium tantalum oxide.

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