A copper antimony selenium thin film for all-solid-state thin film lithium ion battery and a preparation method thereof

Abstract

The application provides a copper antimony selenium thin film for a full solid-state thin film lithium ion battery and a preparation method, and belongs to the technical field of thin film solid-state lithium ion batteries and manufacturing thereof. The specific operation steps are as follows: firstly, a CuSbSe2 precursor is prepared by using a mechanical ball milling method and is vacuum calcined, then a layer of CuSbSe2 is evaporated on a current collector by using a vacuum evaporation method, and finally, heat annealing is performed on the CuSbSe2 thin film in a rapid annealing furnace under the condition of 300-600 DEG C for 30-90 seconds, thereby forming the CuSbSe2 thin film. The process of evaporating first and then annealing can enhance the bonding force between the thin film and the substrate, and improve the purity of the thin film layer, and the preparation process is simple and the cost is low. The CuSbSe2 negative electrode thin film has excellent charge-discharge specific capacity and cycle stability, has a wide development prospect in the field of solid-state thin film batteries, and is suitable for further popularization and application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of all-solid-state thin film lithium ion batteries and their manufacturing, and particularly relates to a copper antimony selenide (CuSbSe2) negative electrode thin film and a preparation method thereof. BACKGROUND

[0002] All-solid-state thin film lithium ion batteries (ASSTFB) have significant advantages in electric vehicles and energy storage systems, especially in terms of fast charging and low temperature performance. With the miniaturization of microelectronic devices, the demand for compact and efficient power sources has increased, and ASSTFB has become an ideal choice due to its high energy density and safety. The development prospects of ASSTFB are broad, and it is expected to be widely used in intelligent devices, medical implants, and wearable technology fields.

[0003] Negative electrode materials play a crucial role in thin film lithium ion batteries. They not only directly affect the energy density and power density of the battery, but also determine the cycle stability and overall performance of the battery. The high specific surface area and good electronic conductivity of the negative electrode thin film help to improve the charging and discharging efficiency of the battery, and the thin film structure is beneficial to improve the mechanical stability and thermal stability of the battery. In addition, the uniformity and consistency of the thin film negative electrode are essential to ensure the reliability of the battery under various working conditions. Currently, common thin film negative electrode materials include lithium titanate and silicon-based materials. Although lithium titanate negative electrode materials have the advantages of fast charging and discharging speed, high cycle number, and high safety, their specific capacity is relatively low. The theoretical specific capacity of silicon-based materials is as high as 4200 mAh / g, but during the charging and discharging process, silicon will undergo severe volume expansion, leading to battery capacity attenuation and coulombic efficiency decline. Therefore, the development of a negative electrode with high specific capacity and high stability is of great significance for the development of all-solid-state thin film lithium ion batteries suitable for harsh environments such as industry and military.

[0004] CuSbSe2 has a theoretical specific capacity of about 470 mAh / g and excellent cycle performance, making it one of the candidates for lithium ion battery negative electrode thin films. Currently, the main method for preparing CuSbSe2 thin films is multi-step magnetron sputtering, which has high cost, slow deposition rate, and complex process steps. SUMMARY

[0005] Therefore, the application provides a CuSbSe2 thin film and a preparation method thereof, which enhances the ion and electron transport properties of the CuSbSe2 thin film and improves the overall performance of the battery.

[0006] The application achieves the above technical effects by adopting the following technical solutions:

[0007] A preparation method of an all-solid-state thin film lithium ion battery, specifically comprising the following steps:

[0008] Step 1, mechanical ball milling to prepare CuSbSe2 precursor material;

[0009] Step 2, the CuSbSe2 precursor material is placed in a vacuum sintering furnace for calcination;

[0010] Step 3, after the current collector is ultrasonically cleaned in a solution, it is placed in an oven for drying;

[0011] Step 4, the calcined CuSbSe2 precursor material is used as an evaporation source to deposit a CuSbSe2 amorphous thin film on the current collector by vacuum evaporation technology;

[0012] Step 5, the CuSbSe2 amorphous thin film material is subjected to rapid thermal annealing in an inert atmosphere to obtain a crystallized CuSbSe2 thin film.

[0013] Further, in step 1, the process parameters of mechanical ball milling are as follows: the rotation speed is 200-400 rpm; and the time is 6-12 h.

[0014] Further, in step 1, the raw materials for mechanical ball milling are Cu powder, Sb powder and Se powder, and the stoichiometric ratio is Cu:Sb:Se=1:1:2.

[0015] Further, in step 2, the process parameters of the vacuum sintering furnace are as follows: the vacuum degree needs to reach 1×10 -3 ~5 Pa; the calcination temperature is 200-500℃; and the time is 0.5-3 h.

[0016] Further, in step 3, the current collector is any one or a mixture of multiple of steel sheet, steel foil, stainless steel sheet, copper sheet, copper foil and foamed copper; and the oven temperature is 45-55℃.

[0017] Further, in step 3, the current collector is sequentially cleaned with acetone, anhydrous ethanol and deionized water; and the cleaning time is 15-30 min.

[0018] Further, in step 4, the process parameters of the vacuum evaporation are as follows: the vacuum degree needs to reach 2×10 -4 ~7×10 -4 Pa; the temperature of the current collector is room temperature 25℃; the distance between the evaporation source and the current collector is 7-12 cm; the current applied to the tungsten boat is 60-80 A; the rotation speed of the substrate tray is 3-10 rpm; and the evaporation time is 15-30 min.

[0019] Further, in step 5, the inert atmosphere is helium, neon, argon or krypton.

[0020] Further, the temperature of the rapid thermal annealing in step 5 is 300-600 DEG C, and the time is 30-90 s.

[0021] The CuSbSe2 negative electrode thin film prepared by the preparation method.

[0022] Compared with the prior art, the application first proposes a method for preparing a CuSbSe2 thin film by using a material obtained by ball-milling Cu powder, Sb powder and Se powder as an evaporation source, and using vacuum evaporation combined with rapid thermal annealing. The method is simple and easy to implement, and has the following advantages:

[0023] ① The three raw materials are non-toxic or low-toxic, easy to obtain and low in cost;

[0024] ② The ball-milling method is simple in process, does not cause environmental pollution, and is high in safety.

[0025] ③ The amorphous CuSbSe2 thin film prepared by vacuum evaporation is uniform in thickness, dense in structure, suitable for complex geometric shapes and fine structures; moreover, the thin film deposition rate is fast, the production efficiency is improved, and the preparation cost is reduced. The evaporation process does not cause environmental pollution, which is conducive to environmental protection.

[0026] ④ The rapid thermal annealing technology can crystallize the amorphous material in a very short time, significantly reduce the stress and defects in the thin film, improve the crystal quality and charge transport efficiency of the thin film; at the same time, the thermal budget can be reduced, and the energy consumption and the influence on the environment are reduced. Therefore, the method proposed by the application provides an efficient, low-cost and excellent-performance solution for manufacturing CuSbSe2 negative electrode thin films for full-solid-state thin film lithium ion batteries. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The structure diagram of the vacuum evaporation equipment used for preparing the CuSbSe2 thin film of the application.

[0028] Figure 2 The XRD diffraction pattern of the CuSbSe2 thin film prepared in Example 1 of the application.

[0029] Figure 3 The SEM image of the CuSbSe2 thin film prepared in Example 1 of the application.

[0030] Figure 4 The cycle charge-discharge curve (0.5 C) of the CuSbSe2 thin film prepared in Example 1 of the application.

[0031] Figure 5 The cycle charge-discharge curve (0.5 C) of the CuSbSe2 thin film prepared in Example 2 of the application.

[0032] Figure 6 Cycling charge-discharge curve (0.5 C) of CuSbSe2 thin film prepared for Example 3 of the present application.

[0033] Figure 7 Cycling charge-discharge curve (0.5 C) of CuSbSe2 powder prepared for Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] Example 1, a preparation method of a copper antimony selenium thin film for a full solid thin film lithium ion battery

[0036] Step 1, Cu powder, Sb powder and Se powder with a molar ratio of 1:1:2 were mixed and placed in a ball mill jar, and anhydrous ethanol was added as a process control agent. The rotation speed of the ball mill was set to 240 rpm, and the time was 8 h. After ball milling, the ball mill jar was placed in a 45 °C drying box, and after drying, a CuSbSe2 precursor was obtained.

[0037] Step 2, the precursor was placed in a vacuum sintering furnace, the calcination temperature was set to 400 °C, and the time was 1 h, and a CuSbSe2 powder material was obtained.

[0038] Step 3, the stainless steel current collector was ultrasonically cleaned, and acetone solution was used to remove residual grease, anhydrous ethanol was used to remove residual acetone, and deionized water was used to remove ethanol residue. Then it was placed in a 45 °C drying box for 12 hours to remove residual moisture.

[0039] Step 4, a high vacuum four-source evaporation film coater as shown in Figure 1 was used for thin film evaporation. Open the vacuum evaporation equipment cavity, open the metal source shutter 5, take out the tray 3 and the tungsten boat 4, polish the impurities on the tray 3 and the tungsten boat 4 with sandpaper, and then wipe them clean with alcohol. Place the cleaned stainless steel current collector on the tray 3, and evenly place the CuSbSe2 powder on the tungsten boat 4 to ensure uniform heating of the powder during heating. Place the tray 3 on the rotating base 2 and fix it. Set the distance between the substrate and the evaporation source to 10 cm, the substrate tray rotation speed to 5 rpm, close the metal source shutter 5, and close the cavity. The cavity vacuum degree is extracted to 5 × 10 -4 Pa, open the tray rotation, open the metal source shutter 5, open the tungsten boat 4 control power, adjust the evaporation current to 80 A, and the evaporation time is 25 min.

[0040] Step 5, the stainless steel current collector on which the thin film is evaporated is placed in a rapid annealing furnace, annealed at 500 °C in an argon atmosphere for 30 s, to obtain a CuSbSe2 thin film.

[0041] The CuSbSe2 thin film prepared in Example 1 is subjected to XRD characterization, and the results are shown in FIG. 2. All peaks of the negative electrode material can be matched with the standard pattern, the thin film growth is preferentially oriented in <020>, and belongs to the Pnma(62) space group.

[0042] The CuSbSe2 thin film prepared in Example 1 is subjected to SEM characterization, and the results are shown in FIG. 3. The negative electrode material presents stacked nanorods.

[0043] The CuSbSe2 thin film prepared in Example 1 is subjected to cyclic charge and discharge test at 0.5 C, and the results are shown in FIG. 4. Figure 4 The discharge specific capacity reaches 1294.35 mAh·g -1 , the charge specific capacity reaches 1259.13 mAh·g -1 , the first coulombic efficiency is 97.28 %, and the capacity retention rate after 200 cycles is 91.22 %, indicating that the method can prepare a CuSbSe2 negative electrode thin film with excellent electrochemical performance.

[0044] Example 2, a preparation method of a copper antimony selenium thin film for a full solid-state thin film lithium ion battery

[0045] Compared with Example 1, in the preparation of the CuSbSe2 thin film, the annealing temperature in the rapid thermal annealing process is adjusted to 400 °C. The remaining steps are the same as those in Example 1.

[0046] The CuSbSe2 negative electrode thin film prepared in Example 2 is subjected to cyclic charge and discharge test at 0.5 C, and the results are shown in FIG. 5. Figure 5

[0047] Example 3, a preparation method of a copper antimony selenium thin film for a full solid-state thin film lithium ion battery

[0048] Compared with Example 1, in the preparation of the CuSbSe2 thin film, the annealing temperature in the rapid thermal annealing process is adjusted to 600 °C. The remaining steps are the same as those in Example 1.

[0049] The CuSbSe2 negative electrode thin film prepared in Example 2 is subjected to cyclic charge and discharge test at 0.5 C, and the results are shown in FIG. 5. Figure 6

[0050] ​​Cu, Sb, and Se powders in a stoichiometric ratio of 1:1:2 were ground in a mortar for 30 minutes, and then the resulting mixture was ground in a 2×10⁻⁶ mortar. - 2 The powder was sealed in a vacuum quartz tube under a pressure of Pa. The quartz tube was then heated to 810°C at a heating rate of 2°C / min and held isothermally for 150 h to obtain CuSbSe2 powder.

[0051] Figure 7 The cyclic charge-discharge curves of the CuSbSe2 powder anode prepared for Comparative Example 1 at a current density of 0.5 C are shown.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a copper antimony selenide thin film for an all-solid-state thin film lithium ion battery, characterized by, The CuSbSe2 thin film is used as a negative electrode thin film, and the thin film is prepared by the following method, specifically comprising the following steps: Step 1, mechanical ball milling to prepare CuSbSe2 precursor material, and the raw materials for mechanical ball milling are Cu powder, Sb powder and Se powder; Step 2, placing the CuSbSe2 precursor material into a vacuum sintering furnace for calcination; Step 3, placing the current collector into a solution for ultrasonic cleaning, and then placing the current collector into an oven for drying; Step 4, using the calcined CuSbSe2 precursor material as an evaporation source, and using a vacuum evaporation technology to deposit CuSbSe2 amorphous thin film on the current collector; Step 5, performing rapid thermal annealing on the CuSbSe2 amorphous thin film material in an inert atmosphere to obtain a crystallized CuSbSe2 negative electrode thin film, and the CuSbSe2 negative electrode thin film presents stacked nanorods.

2. The method for preparing copper antimony selenium thin film for all-solid-state thin film lithium ion battery according to claim 1, characterized in that, In the step 1, the process parameters of mechanical ball milling are as follows: the rotating speed is 200-400 rpm, and the time is 6-12 h.

3. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. In the step 1, the stoichiometric ratio of Cu powder, Sb powder and Se powder is Cu:Sb:Se=1:1:

2.

4. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. The process parameters of the vacuum sintering furnace in step 2 are as follows: vacuum degree 1×10 -3 5 Pa; calcination temperature 200-500℃; and time 0.5-3 h.

5. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. In the step 3, the current collector is any one or a mixture of multiple of the following: steel sheet, steel foil, stainless steel sheet, copper sheet, copper foil and foamed copper, and the temperature of the oven is 45-55 °C.

6. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. In the step 3, the current collector sequentially passes through acetone, anhydrous ethanol and deionized water for cleaning, and the cleaning time is 15-30 min.

7. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. The process parameters of vacuum evaporation in step 4: the vacuum degree needs to reach 2x10 -4 ~7x10 -4 Pa; the temperature of the current collector is room temperature 25℃; the distance between the evaporation source and the current collector is 7~12 cm; the current applied to the tungsten boat is 60~80 A; the rotation speed of the substrate tray is 3~10 rpm; the evaporation time is 15~30 min.

8. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. In the step 5, the inert atmosphere is helium, neon, argon or krypton.

9. The method of claim 1, wherein the copper antimony selenium thin film is prepared by a process comprising: depositing a copper thin film on a substrate; depositing an antimony thin film on the copper thin film; and depositing a selenium thin film on the antimony thin film. In the step 5, the temperature of the rapid thermal annealing is 300-600 °C, and the time is 30-90 s.

10. A copper antimony selenide thin film for an all-solid-state thin film lithium ion battery, characterized by, The CuSbSe2 negative electrode thin film is prepared by the preparation method of any one of claims 1-9.

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