CN116240494A - Magnesium-based ternary hydrogen storage alloy film and preparation method thereof - Google Patents

Abstract

The invention discloses a magnesium-based ternary hydrogen storage alloy thin film and a preparation method thereof. The magnesium-based ternary hydrogen storage alloy thin film structure includes a magnesium-based ternary alloy layer, a catalytic layer and a surface covering layer arranged in sequence. The element composition of the magnesium-based ternary alloy layer is Mg ₈₀ Ni ₁₆ V ₄ . The elemental composition of the catalytic layer and the surface covering layer is Pd. The method co-sputters and co-deposits a Mg-Ni alloy target and a high-purity V target on a pretreated substrate by physical vapor deposition (PVD), interspersed with sputtering deposition of a high-purity Pd target to obtain a Pd catalytic layer , and finally deposit a layer of Pd on the surface of the film as a surface covering layer to encapsulate the film. The magnesium-based ternary hydrogen storage alloy film prepared by the invention has the advantages of simple preparation process, low cost, and reversible hydrogen absorption and desorption at low temperature. Its hydrogen absorption and desorption can be carried out at 150°C, and the reversible hydrogen storage capacity can reach more than 3.8wt.% after activation at 150°C. Compared with pure magnesium for hydrogen storage (the lowest hydrogen desorption temperature of pure magnesium is about 400°C), its dehydrogenation temperature is significantly lower.

Description

A kind of magnesium-based ternary hydrogen storage alloy thin film and preparation method thereof

technical field

The invention relates to the field of solid-state hydrogen storage, in particular to a magnesium-based ternary hydrogen storage alloy film and a preparation method thereof.

Background technique

Magnesium hydride (MgH ₂ ) remains one of the most promising candidates for hydrogen storage due to its high theoretical hydrogen storage capacity, reversibility, reasonable price, earth-abundant reserves, and environmental friendliness. However, due to its high thermodynamic stability and extremely poor kinetic properties, the application prospects of pure magnesium for hydrogen storage are facing great difficulties. In the past decades, many methods have been adopted to improve the hydrogen storage properties of pure magnesium, among which alloying and catalyst addition are two commonly used methods. For the addition of catalysts, numerous studies have shown that transition metals (TM) and their hydrides can improve the hydrogen storage of pure Mg by providing active nucleation sites for the nucleation of α-Mg and fast channels for the diffusion of H atoms, respectively. performance. For alloying, Mg ₂ Ni alloy is a typical representative, and the enthalpy of formation of its hydride Mg ₂ NiH ₄ is significantly reduced to -64.5kJ/mol relative to pure MgH ₂ , which means that compared to pure MgH ₂ , Mg _{2 NiH4} can release hydrogen gas at lower temperature. On the basis of the Mg ₂ Ni alloy, in order to further improve its hydrogen storage properties, a lot of research has been done on the partial substitution of A-side and B-side elements through alloying. For example, the dehydrogenation activation energy and cycle stability of Mg ₂ Ni can be reduced and improved by alloying with Ti and Cr respectively [Wang X.,TuJ., Zhang X., et al.The Chinese Journal of Nonferrous Metals,12 (2002) 907-911.] [Liang G., Huot J., Boily S., et al. J. Alloys Compd. 282(1999) 286-290.].

In addition to the commonly used mechanical alloying, thin film technology has also been widely used in the research of magnesium-based hydrogen storage materials due to its advantages of precise control of material composition, interface and grain size. For example, Tan et al [Tan X., Danaie M., Kalisvaart WP, et al.Int.J.Hydrogen Energy 36(2011) 2154-2164.] prepared Mg-15at.%Ni film by magnetron sputtering , which can release more than 4.5wt.% of hydrogen at 200°C. In addition, good hydrogen absorption kinetics were also found in the Mg ₈₄ Ni ₁₆ /Pd film, which can absorb hydrogen and saturate within 45s, which is mainly due to the increase of Mg ₂ Ni in the Mg ₈₄ Ni ₁₆ /Pd film. The hydrogen diffusion rate is determined and additional interfacial energy is introduced [Liu T., Cao Y., XinG., et al. Dalton Trans.42(2013) 13692.]. These works show that thin-film technology is an effective method to study the hydrogen storage properties of Mg-based alloys. However, the above-mentioned Mg2Ni alloy and Mg84Ni16/Pd film still have defects such as high hydrogen desorption starting temperature, insufficient low-temperature hydrogen desorption capacity, and poor cycle stability.

Contents of the invention

The first object of the present invention is to provide a magnesium-based ternary hydrogen storage alloy film, which has a low hydrogen desorption initiation temperature, excellent hydrogen desorption capacity at low temperature and good cycle stability.

In order to achieve the purpose of the above invention, the magnesium-based ternary hydrogen storage alloy thin film of the present invention is characterized in that it comprises a magnesium-based ternary alloy layer, a catalytic layer, a magnesium-based ternary alloy layer and a surface covering layer arranged in sequence.

The elemental composition of the magnesium-based ternary alloy layer is Mg ₈₀ Ni ₁₆ V ₄ , the matrix is mainly composed of ultrafine nano-crystals of Mg and V, and Mg ₂ Ni(V) solid solution phase is evenly distributed in the matrix.

Further, the elemental composition of the magnesium-based ternary alloy layer is preferably Mg ₈₀ Ni ₁₆ V _{4 .}

The main component of the catalytic layer and the surface covering layer is Pd.

Further, the total thickness of the magnesium-based ternary alloy layer is 300 nm, the thickness of the catalytic layer is 1 nm, and the thickness of the surface covering layer is 10 nm.

The second object of the present invention is to provide a method for preparing the above-mentioned magnesium-based ternary hydrogen storage alloy film, which specifically includes the following steps:

A. Carry out surface pre-cleaning treatment to the substrate;

B. Using the radio frequency magnetron sputtering method on the substrate after the above pretreatment, after pre-sputtering, adjust the sputtering power, sputtering time, argon flow rate, turntable temperature, and turntable speed of the target during sputtering Parameter formal sputtering deposition of magnesium-based ternary alloy layer;

C, using the DC magnetron sputtering method to in-situ sputter deposition catalyst layer on the magnesium-based ternary alloy layer;

D, repeating step B, sputtering deposition magnesium-based ternary alloy layer on catalytic layer;

E, using the DC magnetron sputtering method to in-situ sputter the surface covering layer on the magnesium-based ternary alloy layer;

Wherein, the base material selected in the above steps is glass, silicon wafer or aluminum foil.

In step A, the specific steps of the pretreatment are as follows:

Place the substrate in deionized water for ultrasonic cleaning, take it out and then place it in acetone for ultrasonic cleaning, then take it out and place it in ethanol for ultrasonic cleaning, and finally dry it with nitrogen gas. The parameters of temperature, time, and ultrasonic power in ultrasonic cleaning were 50°C, 15min, and 75%, respectively.

In steps B, C, D, and E, during formal sputtering, the pressure in the magnetron sputtering chamber is lower than 5×10 ^-3 Pa after pre-evacuation; the argon used is high-purity argon (argon purity ≥ 99.999%), the input argon flow rate is 80ml/min, and the chamber pressure rises to 0.8Pa after filling with argon; the range of the turntable temperature T is: 40°C<T<45°C, and the turntable speed is 10r/min . When depositing the magnesium-based ternary alloy layer, the elemental composition of the Mg-Ni alloy target used is Mg ₈₀ Ni ₂₀ , and the sputtering powers of the Mg-Ni alloy target and the V target are 120-180W and 25-75W respectively. The total time for target co-deposition and co-sputtering is 14min; when depositing the catalytic layer and the surface covering layer, the purity of the Pd target used is ≥99.99%, the sputtering power of the Pd target is constant at 50W, and the sputtering time is 5s and 48s.

The purpose of the pre-sputtering in step B is to eliminate the oxide layer and other impurities on the surface of the target and prepare for the subsequent formal sputtering. The argon gas flow rate, turntable temperature and turntable rotation speed during pre-sputtering are the same as the above-mentioned formal sputtering. The difference is that the sputtering baffle is adjusted to cover the target during pre-sputtering to prevent impurities sputtered during pre-sputtering from depositing on the substrate. The sputtering power of Mg-Ni alloy target and V target used in pre-sputtering is 75W, and the sputtering time is 300s.

The present invention has the following advantages:

(1) The preparation of Mg-Ni-V ternary alloy thin films by radio frequency magnetron sputtering has the advantages of simple operation process, stable process conditions, easy control and high preparation efficiency. In addition, the introduction of V can form the _VH2 phase after hydrogenation and the VH phase upon dehydrogenation. Because the electronic interaction between V and H atoms is stronger than that between Mg and H atoms, the existence of VH phase will weaken the bonding between Mg and H atoms, which will help the formation of α-Mg phase at the MgH ₂ /VH interface. The addition of Ni helps to form Mg ₂ Ni, provides a fast channel for the diffusion of H atoms, and promotes the hydrogen absorption and desorption process of the film.

(2) The D-Mg ₈₀ Ni ₁₆ V ₄ film with the best performance has an initial hydrogen desorption temperature of 37°C and a peak hydrogen desorption temperature of 196°C. The hydrogenated D-Mg ₈₀ Ni ₁₆ V ₄ film released 2.2 wt.% hydrogen within 6 h during the first dehydrogenation cycle at 150 °C, and its reversible hydrogen storage capacity increased to 3.87 wt.%. The Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film without Pd catalytic interlayer has a slightly lower onset and peak hydrogen desorption temperature than the D-Mg ₈₀ Ni ₁₆ V ₄ film with Pd catalytic interlayer, about 41℃ and 207°C. In addition, the hydrogenated Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer without Pd catalytic interlayer can release 1.48wt.% hydrogen within 10h at 150℃. The excellent hydrogen storage performance of the D-Mg ₈₀ Ni ₁₆ V ₄ film can be attributed to the existence of the VH/V phase which weakens the Mg-H/Ni-H bonding strength, making MgH ₂ /Mg ₂ NiH ₄ available at a lower temperature The hydrogen desorption rate of the film is also accelerated under the desorption of H, while Ni is used as a catalyst.

(3) The D-Mg ₈₀ Ni ₁₆ V ₄ film prepared by radio frequency magnetron sputtering has excellent hydrogen storage performance, which can be used to prepare Mg-Ni-TM (TM is a transition metal element) with excellent hydrogen storage performance. ) Ternary alloys provide guidance.

Description of drawings

Figure 1 is a schematic structural view of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film (a) and the D-Mg ₈₀ Ni ₁₆ V ₄ film (b) prepared in Example 1 and 2 of the present invention.

Fig. 2 is an XRD pattern of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film prepared in Example 1 of the present invention.

Fig. 3 is an XRD pattern of the D-Mg ₈₀ Ni ₁₆ V ₄ film prepared in Example 2 of the present invention.

Figure 4 is the SEM image of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film and the D-Mg ₈₀ Ni ₁₆ V ₄ film prepared in Examples 1 and 2 of the present invention, where a and c are Mg ₈₀ Ni ₁₆ V ₄ / The surface and cross-sectional SEM images of the Pd monolayer film, b and d are the surface and cross-sectional SEM images of the D-Mg ₈₀ Ni ₁₆ V ₄ film, respectively.

Figure 5 is the HRTEM image and selected area electron diffraction image of the D-Mg ₈₀ Ni ₁₆ V ₄ thin film prepared in Example 2 of the present invention (the selected area is the area in the black circle, emphasizing the calibration of the Mg ₂ Ni(V) solid solution phase) .

Fig. 6 is the TPD-MS data of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film and the D-Mg ₈₀ Ni ₁₆ V ₄ thin film prepared in Examples 1 and 2 of the present invention.

Figure 7 is the hydrogen desorption kinetic curves of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film and the D-Mg ₈₀ Ni ₁₆ V ₄ film prepared in Examples 1 and 2 of the present invention, and the D-Mg prepared in Example 2 of the present invention Hydrogen desorption cycle curves of ₈₀ Ni ₁₆ V ₄ films.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but the implementation manners of the present invention are not limited thereto.

Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the protection scope of the present invention.

For the hydrogen storage performance test method of the magnesium-based ternary hydrogen storage alloy film, QIC-20 (TPD-MS) is used to test the hydrogen desorption temperature of the hydrogenated sample; HyEnergy PCTPro 2000 is used to test the hydrogen desorption and cycle desorption performance of the sample.

The test method for the hydrogen release temperature of the hydrogenated sample is: put the deposited sample in a reactor and fill it with 3MPa hydrogen, raise the temperature to 150°C for 3 hours, take out the sample after air cooling, and then place it in a quartz tube. Connect the quartz tube containing the hydrogenated sample to the trachea, and continuously flow argon through the trachea for 20 minutes of scrubbing to reduce the water and oxygen content during the test. After the gas washing is completed, continue to pass in argon gas to start the temperature rise desorption test, in which the starting temperature of the sample is room temperature, the heating rate is 2°C/min, and the end point temperature is 450°C.

The test method of hydrogen desorption kinetic performance is as follows: put about 20mg of the deposited sample in the sample rod, vacuumize the sample after installation, fill it with 3MPa hydrogen and raise the temperature, and the heating rate is 5°C/min. When the temperature rises to 150°C, keep it warm for 3 hours. Then, the hydrogen desorption kinetic performance test was started at 150°C, and the hydrogen desorption initial hydrogen pressure was 0 bar.

The test method for the kinetic performance of the hydrogen desorption cycle is: put about 20 mg of the deposited sample in the sample rod, vacuumize the sample and raise the temperature after the sample is installed, and the heating rate is 5°C/min. When the temperature rises to 150°C, the kinetic performance test of the hydrogen desorption cycle begins. The hydrogen absorption pressure is 3MPa, the hydrogen absorption time is 3h, and the hydrogen desorption initial hydrogen pressure is 0bar.

Example 1:

Preparation of Mg ₈₀ Ni ₁₆ V ₄ /Pd Monolayer Film

Specifically include the following steps:

A. Carry out surface pre-cleaning treatment to the substrate;

B. Using radio frequency magnetron sputtering method on the substrate after the above pretreatment, after pre-sputtering, adjust the sputtering power, sputtering time, argon flow rate, turntable temperature, turntable speed, etc. of the target during sputtering Process parameters Formal sputtering deposition of magnesium-based ternary alloy layer;

C, using the DC magnetron sputtering method to in-situ sputter the surface covering layer on the magnesium-based ternary alloy layer;

Among them, the substrate materials selected according to different test requirements in the above steps are glass substrates for XRD tests, silicon wafers for SEM and TEM tests, and aluminum foil for hydrogen storage performance tests.

In step A, the specific steps of the pretreatment are as follows:

Place the substrate in deionized water for ultrasonic cleaning, take it out and then place it in acetone for ultrasonic cleaning, then take it out and place it in ethanol for ultrasonic cleaning, and finally dry it with nitrogen gas. The parameters of temperature, time, and ultrasonic power in ultrasonic cleaning were 50°C, 15min, and 75%, respectively.

In steps B and C, during formal sputtering, the pressure in the magnetron sputtering chamber after pre-evacuation is lower than 5×10 ^-3 Pa; the argon used is high-purity argon (argon purity ≥ 99.999%), The input argon flow rate is 80ml/min, and the chamber pressure rises to 0.8Pa after filling with argon; the range of the turntable temperature T is: 40°C<T<45°C, and the turntable speed is 10r/min. When depositing the magnesium-based ternary alloy layer, the elemental composition of the Mg-Ni alloy target used is Mg ₈₀ Ni ₂₀ , the sputtering powers of the Mg-Ni alloy target and the V target are 120W and 25W respectively, and the two targets are co-deposited 1. The total time of co-sputtering is 14min; when depositing the surface covering layer, the purity of the Pd target used is ≥99.99%, the sputtering power of the Pd target is constant at 50W, and the sputtering time is 48s.

The purpose of the pre-sputtering in step B is to eliminate the oxide layer and other impurities on the surface of the target and prepare for the subsequent formal sputtering. The argon flow rate, turntable temperature and turntable rotation speed during pre-sputtering are the same as the argon flow rate, turntable temperature and turntable rotation speed described in formal sputtering. The difference is that the sputtering baffle is adjusted to cover the target during pre-sputtering to prevent impurities sputtered during pre-sputtering from depositing on the substrate. The sputtering power of the Mg-Ni alloy target and the V target used in the pre-sputtering is the same as 75W, and the sputtering time is also 300s.

Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film is used for X-ray powder diffraction (XRD, PANalytical Empyrean), the test conditions are: using Cu-Kα rays, the power is 45KV×40mA, the step size is 0.02°, and the test range is 25～ 70°, only Pd diffraction peaks appear as a result, as shown in Figure 2.

In order to verify the existence of Mg, Ni and V, a pure Mg ₈₀ Ni ₁₆ V ₄ monolayer film was prepared without Pd plating as a comparative example for XRD testing, and the diffuse scattering peaks of Mg and V appeared as a result, as shown in Figure 2.

Using a scanning electron microscope (SEM, TESCAN GAIA3) to observe the scanning image of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film, the results show that the surface of the film is mainly composed of circular island-shaped nanoparticles with a particle size of about 24nm, as shown in Figure 4 . The TPD-MS test was performed on the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film, and the test results showed that the onset and peak hydrogen desorption temperatures were 41°C and 207°C, respectively, as shown in Figure 6. In addition, the hydrogen desorption performance of the Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film was tested, and the test results showed that the hydrogenated Mg ₈₀ Ni ₁₆ V ₄ /Pd monolayer film without the addition of Pd catalyst layer could be released at 150 ° C for 10 h 1.48wt.% hydrogen is released, as shown in Figure 7.

Example 2:

The preparation method of D-Mg ₈₀ Ni ₁₆ V ₄ film specifically comprises the following steps:

A. Carry out surface pre-cleaning treatment to the substrate;

B. Using the radio frequency magnetron sputtering method on the substrate after the above pretreatment, after pre-sputtering, adjust the sputtering power, sputtering time, argon flow rate, turntable temperature, and turntable speed of the target during sputtering Parameter formal sputtering deposition of magnesium-based ternary alloy layer;

C, using the DC magnetron sputtering method to in-situ sputter deposition catalyst layer on the magnesium-based ternary alloy layer;

D, repeating step B, sputtering deposition magnesium-based ternary alloy layer on catalytic layer;

E, using the DC magnetron sputtering method to in-situ sputter the surface covering layer on the magnesium-based ternary alloy layer;

Among them, the substrate materials selected according to different test requirements in the above steps are glass substrates for XRD tests, silicon wafers for SEM and TEM tests, and aluminum foil for hydrogen storage performance tests.

In step A, the specific steps of the pretreatment are as follows:

Place the substrate in deionized water for ultrasonic cleaning, take it out and then place it in acetone for ultrasonic cleaning, then take it out and place it in ethanol for ultrasonic cleaning, and finally dry it with nitrogen gas. The parameters of temperature, time, and ultrasonic power in ultrasonic cleaning were 50°C, 15min, and 75%, respectively.

In steps B, C, D, and E, during formal sputtering, the pressure in the magnetron sputtering chamber is lower than 5×10 ^-3 Pa after pre-evacuation; the argon used is high-purity argon (argon purity ≥ 99.999%), the input argon flow rate is 80ml/min, and the chamber pressure rises to 0.8Pa after filling with argon; the range of the turntable temperature T is: 40°C<T<45°C, and the turntable speed is 10r/min . When depositing the magnesium-based ternary alloy layer, the elemental composition of the Mg-Ni alloy target used is Mg ₈₀ Ni ₂₀ , the sputtering powers of the Mg-Ni alloy target and the V target are 120W and 25W respectively, and the two targets are co-deposited 1. The total time of sputtering is 14min; when depositing the catalytic layer and the surface covering layer, the purity of the Pd target used is ≥99.99%, the sputtering power of the Pd target is constant at 50W, and the sputtering time is 5s and 48s respectively.

The purpose of the pre-sputtering in step B is to eliminate the oxide layer and other impurities on the surface of the target and prepare for the subsequent formal sputtering. The argon flow rate, turntable temperature and turntable rotation speed during pre-sputtering are the same as the argon flow rate, turntable temperature and turntable rotation speed described in formal sputtering. The difference is that the sputtering baffle is adjusted to cover the target during pre-sputtering to prevent impurities sputtered during pre-sputtering from depositing on the substrate. The sputtering power of the Mg-Ni alloy target and the V target used in the pre-sputtering is the same as 75W, and the sputtering time is also 300s.

D-Mg ₈₀ Ni ₁₆ V ₄ film is used for X-ray powder diffraction (XRD, PANalytical Empyrean), the test conditions are: using Cu-Kα rays, the power is 45KV×40mA, the step size is 0.02°, and the test range is 25-70° , resulting in Pd and Mg ₆ Pd diffraction peaks, as shown in Figure 3. The scanning electron microscope (SEM, TESCAN GAIA3) was used to observe the scanning image of the D-Mg ₈₀ Ni ₁₆ V ₄ film. The results showed that the surface of the film was mainly composed of circular island-shaped nanoparticles with a particle size of about 25 nm, as shown in Figure 4. High-resolution images of D-Mg ₈₀ Ni ₁₆ V ₄ films were observed by transmission electron microscopy (TEM, Talos F200x), and the results showed that the film matrix was mainly composed of ultrafine nanocrystals of Mg and V, in which Mg ₂ Ni(V) was uniformly embedded Phase, as shown in Figure 5. The TPD-MS test was performed on the D-Mg ₈₀ Ni ₁₆ V ₄ film, and the test results showed that the onset and peak hydrogen desorption temperatures after hydrogenation were 37 °C and 196 °C, respectively, as shown in Figure 6. In addition, the hydrogen desorption performance test of D-Mg ₈₀ Ni ₁₆ V ₄ film was carried out. The test results showed that the hydrogenated D-Mg ₈₀ Ni ₁₆ V ₄ film could release hydrogen within 6 hours in the first dehydrogenation cycle at 150°C. 2.2wt.% hydrogen, and after activation, its reversible hydrogen storage capacity can increase to 3.87wt.%, as shown in Figure 7

As mentioned above, the present invention can be better realized, and the above-described embodiments are only partial embodiments of the present invention, and are not used to limit the implementation scope of the present invention; The scope of protection required by the claims of the present invention is covered.

Claims (8)

1. A magnesium-based ternary hydrogen storage alloy film is characterized by comprising a magnesium-based ternary alloy layer and a catalyst which are sequentially arrangedA layer, a magnesium-based ternary alloy layer and a surface covering layer, wherein the element composition of the magnesium-based ternary alloy layer is Mg ₈₀ Ni ₁₆ V ₄ The main components of the catalytic layer and the surface covering layer are Pd.

2. A magnesium-based ternary hydrogen storage alloy film according to claim 1, wherein the matrix of the magnesium-based ternary alloy layer mainly comprises ultrafine nanocrystals of Mg and V, and Mg is uniformly distributed in the matrix ₂ Ni (V) solid solution phase.

3. A magnesium-based ternary hydrogen storage alloy film according to claim 1, wherein the total thickness of the magnesium-based ternary alloy layer is 300nm, the thickness of the catalytic layer is 1nm, and the thickness of the surface coating layer is 10nm.

4. A method for preparing a magnesium-based ternary hydrogen storage alloy film according to any one of claims 1 to 3, wherein the method specifically comprises the following steps:

A. carrying out surface pre-cleaning treatment on the substrate;

B. a radio frequency magnetron sputtering method is adopted to perform formal sputtering deposition of a magnesium-based ternary alloy layer on the pretreated substrate through regulating and controlling sputtering power, sputtering time, argon flow rate, turntable temperature and turntable rotating speed technological parameters of a target material during sputtering after the pre-sputtering;

C. a direct current magnetron sputtering method is adopted to perform in-situ sputtering deposition of a catalytic layer on the magnesium-based ternary alloy layer;

D. repeating the step B, and sputtering and depositing a magnesium-based ternary alloy layer on the catalytic layer;

E. and sputtering a surface coating layer on the magnesium-based ternary alloy layer in situ by adopting a direct current magnetron sputtering method.

5. A method for preparing a magnesium-based ternary hydrogen storage alloy film according to claim 4, wherein the substrate material selected in the step A is glass, silicon wafer or aluminum foil.

6. A method for preparing a magnesium-based ternary hydrogen storage alloy film according to claim 4, wherein in the step a, the pretreatment specifically comprises the following steps:

placing the substrate in deionized water for ultrasonic cleaning, placing the substrate in acetone for ultrasonic cleaning after taking out, then taking out the substrate and placing the substrate in ethanol for ultrasonic cleaning, and finally drying the substrate by using nitrogen, wherein the temperature, time and ultrasonic power parameters in ultrasonic cleaning are respectively 50 ℃,15 minutes and 75 percent.

7. A method for preparing a magnesium-based ternary hydrogen storage alloy film as claimed in claim 4, wherein in step B, C, D, E, the pressure in a magnetron sputtering chamber after forevacuumizing is lower than 5×10 during formal sputtering ^-3 Pa；

The argon is high-purity argon with the purity of more than or equal to 99.999 percent, the flow rate of the input argon is 80ml/min, and the pressure of the chamber is raised to 0.8Pa after the argon is filled;

the temperature range T of the turntable is as follows: the temperature is 40 ℃ and the temperature is less than 45 ℃, and the rotating speed of the turntable is 10r/min;

when the magnesium-based ternary alloy layer is deposited, the adopted Mg-Ni alloy target element comprises Mg ₈₀ Ni ₂₀ The sputtering power of the Mg-Ni alloy target and the V target is 120-180W and 25-75W respectively, and the total codeposition and codeposition time of the two targets is 14min;

when the catalytic layer and the surface covering layer are deposited, the purity of the adopted Pd target is more than or equal to 99.99 percent, the sputtering power of the Pd target is constant at 50W, and the sputtering time is respectively 5s and 48s.

8. A preparation method of a magnesium-based ternary hydrogen storage alloy film is characterized in that in the step B, the purpose of pre-sputtering is to eliminate an oxide layer and other impurities on the surface of a target material, preparation is made for subsequent formal sputtering, and the flow rate of argon, the temperature of a turntable and the rotating speed of the turntable are the same as those of the formal sputtering during the pre-sputtering;

the difference is that the sputtering baffle plate is adjusted to cover the target material during the pre-sputtering, so that the impurities sputtered during the pre-sputtering are prevented from being deposited on the substrate, the sputtering power of the Mg-Ni alloy target and the V target adopted during the pre-sputtering is 75W, and the sputtering time is 300s.

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