A LiTaOCl4 material, its preparation method and application

Abstract

This invention discloses a LiTaOCl4 material, its preparation method, and its applications. The preparation method includes the following steps: Step 1: Using anhydrous LiOH and TaCl5 as raw materials, amorphous LiTaOCl4 material is synthesized by solid-state ball milling; Step 2: The amorphous LiTaOCl4 material is placed in a vacuum-sealed quartz tube, and the quartz tube is heated to 200–400°C and held for 150–300 min in a tube furnace, followed by rapid cooling with liquid nitrogen; Step 3: The rapidly cooled quartz tube is again heated to 100–300°C and held for 100–300 min in a tube furnace, and after natural cooling to room temperature, it is ground to obtain the LiTaOCl4 material. This invention provides the application of the described LiTaOCl4 material as a solid electrolyte in all-solid-state lithium batteries. The preparation method of this invention has good reproducibility, and the LiTaOCl4 material exhibits high ionic conductivity.

Description

Technical Field

[0001] This invention relates to a LiTaOCl4 material, its preparation method, and its applications. Background Technology

[0002] All-solid-state lithium batteries (ASSLBs) have garnered considerable interest due to their high energy density and potential for improved safety. Solid electrolytes (SEs) are a key component of ASSLBs, and halide solid electrolytes, as an important branch, have received significant attention. To address the issue of insufficient ionic conductivity in halide solid electrolytes, oxygen doping to form oxyhalide solid electrolytes can effectively improve their ionic conductivity, contributing to better commercial applications.

[0003] LiTaOCl4, due to its high ionic conductivity and excellent electrochemical performance, has broad application prospects in the field of all-solid-state batteries. Currently, the heat treatment process for LiTaOCl4 materials suffers from limitations in improving ionic conductivity and poor reproducibility. This invention constructs a new crystal structure for LiTaOCl4 material through a special heat treatment, which significantly improves the ionic conductivity of LiTaOCl4 material with good reproducibility, providing a better foundation for subsequent modification and innovation of LiTaOCl4 materials. Summary of the Invention

[0004] To address the limitations of existing heat treatment processes for LiTaOCl4 materials in improving ionic conductivity and their poor repeatability, this invention proposes a method for preparing LiTaOCl4, a novel LiTaOCl4 material with a new structure, and its applications. This preparation method offers good repeatability, and the LiTaOCl4 material exhibits high ionic conductivity.

[0005] The technical solution of the present invention will be described in detail below.

[0006] In a first aspect, the present invention provides a method for preparing LiTaOCl4 material, comprising the following steps:

[0007] Step 1: Amorphous LiTaOCl4 material was synthesized by solid-state ball milling using anhydrous LiOH and TaCl5 as raw materials.

[0008] Step 2: Place the amorphous LiTaOCl4 material in a vacuum-sealed quartz tube, place the quartz tube in a tube furnace and heat it to 200-400℃ at a rate of 5-20℃ / min, hold it at that temperature for 150-300min, and then rapidly cool the quartz tube with liquid nitrogen.

[0009] Step 3: Place the rapidly cooled quartz tube back into the tube furnace and heat it to 100-300℃ at a rate of 5-20℃ / min. Hold the temperature for 100-300min. After naturally cooling to room temperature, remove the product and grind it to obtain LiTaOCl4 material.

[0010] Step 1 of the present invention can be implemented according to the operating steps reported in the existing literature. Specifically, the following steps can be adopted: (a) Take commercial anhydrous LiOH and TaCl5 and mix them thoroughly in an agate mortar in a glove box filled with argon gas according to the stoichiometric ratio of LiTaOCl4.

[0011] (b) The mixed material obtained in step (a) is placed in a zirconia jar with zirconia balls at a ball-to-powder mass ratio of 10–20:1 (preferably 15:1) and ball milled in an environment filled with an inert gas (such as argon) to obtain a LiTaOCl4 ball-milled sample, i.e., amorphous LiTaOCl4. Preferably, the ball milling conditions are: a ball milling speed of 400–600 rpm (more preferably 500 rpm) and a ball milling time of 30–50 h (more preferably 40 h).

[0012] Preferably, in step 2, the heating rate is 5-20℃ / min, and the temperature is maintained at 300℃ for 3 hours.

[0013] Preferably, in step 3, the heating rate is 5-20℃ / min, and the temperature is heated to 150-250℃ and held for 2 hours, more preferably heated to 200℃ and held for 2 hours.

[0014] The preparation method of the LiTaOCl4 material of the present invention preferably consists of steps 1 to 3.

[0015] Secondly, the present invention provides a LiTaOCl4 material prepared according to the preparation method described in the first aspect. This LiTaOCl4 solid electrolyte material has a partially crystalline structure.

[0016] Thirdly, the present invention provides the application of the LiTaOCl4 material described in the second aspect as a solid electrolyte in all-solid-state lithium batteries.

[0017] Compared with the prior art, the beneficial effects of this invention are mainly reflected in:

[0018] 1) This invention uses amorphous LiTaOCl4 material as the substrate medium and synthesizes a new LiTaOCl4 powder under special heat treatment. Compared with amorphous LiTaOCl4 material, the obtained new LiTaOCl4 powder has higher ionic conductivity.

[0019] 2) The preparation process of the present invention is simple, highly reproducible, and produces no wastewater or waste gas, making it easy to implement on an industrial scale. Attached Figure Description

[0020] Figure 1 These are XRD comparison images of LiTaOCl4 prepared in Examples 1, 2, and 3 and amorphous LiTaOCl4, where BM represents the amorphous LiTaOCl4 material prepared in Example 1. The XRD patterns show that the main diffraction peak angle of the LiTaOCl4 material synthesized in this invention is 11.4°, which is different from the LiTaOCl4 materials reported previously.

[0021] Figure 2 These are EIS comparison images of LiTaOCl4 prepared in Examples 1, 2, and 3 and amorphous LiTaOCl4.

[0022] Figure 3 This is a SEM image of LiTaOCl4 prepared in Example 2. Specific implementation methods

[0023] The technical solution of the present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through conventional technical means or commercially available.

[0025] Example 1

[0026] 2.151 g of TaCl5 powder (99.9% purity) and 0.144 g of LiOH powder (99.9% purity) were placed in an agate mortar and manually ground for 10 min. The ground powder was then transferred to a zirconia vacuum ball mill jar, and 30 g of zirconia grinding beads with a diameter of 5 mm were added. After sealing, the jar was ball-milled at 500 rpm for 40 h in an argon-filled environment. After ball milling, the resulting amorphous LiTaOCl4 initial sample was collected (its XRD pattern is shown in [reference needed]). Figure 1 The product was placed in a quartz tube, vacuum sealed, and heated to 300°C in a tube furnace at a heating rate of 5°C / min, and held at that temperature for 3 hours. After holding, the vacuum quartz tube was immediately removed and immersed in a beaker containing liquid nitrogen. After cooling, it was heated again in the tube furnace at the same heating rate to 150°C, held for 2 hours, and after normal cooling, the product was ground to obtain LiTaOCl4 material. Its XRD pattern is shown below. Figure 1 .

[0027] Solid-state mold batteries were fabricated using the LiTaOCl4 material powder obtained in Example 1 according to the following method.

[0028] Weigh 100 mg of LiTaOCl4 powder sample and press it into a solid disc with a diameter of 1 cm. Place the disc between two stainless steel rods and assemble it into a mold battery in a glove box filled with argon gas. Figure 2 The image shows the EIS curves of the corresponding battery tested in the frequency range of 0.1–100000 Hz and with a voltage amplitude of 5 mV. According to the formula for calculating ionic conductivity: σ = L / (R × A) (L: thickness; R: resistance; A: cross-sectional area), the ionic conductivity of the LiTaOCl4 material in Example 1 of this invention is 1.01 × 10⁻⁶. -2 S cm -1 .

[0029] Example 2

[0030] 2.151g of TaCl5 powder and 0.144g of LiOH powder were placed in an agate mortar and manually ground for 10 minutes. The ground powder was then transferred to a zirconia vacuum ball mill jar, and 30g of zirconia grinding beads with a diameter of 5mm were added. After sealing, the jar was ball-milled at 500 rpm for 40 hours in an argon-filled environment. After ball milling, the resulting amorphous LiTaOCl4 initial sample was collected, placed in a quartz tube, vacuum sealed, and heated to 300℃ in a tube furnace at a heating rate of 5℃ / min, and held for 3 hours. After the holding period, the vacuum quartz tube was immediately removed and immersed in a beaker containing liquid nitrogen. After cooling, it was heated again in the tube furnace at the same heating rate to 200℃, held for 2 hours, and after normal cooling, the product was ground to obtain LiTaOCl4 material. Its XRD pattern is shown below. Figure 1 SEM image (see) Figure 3 . Figure 3 The synthesized LiTaOCl4 exhibits an inhomogeneous particle morphology, indicating that it is not a fully crystalline structure, but rather a partially crystalline structure.

[0031] Solid-state mold batteries were fabricated using the LiTaOCl4 material powder obtained in Example 2 according to the following method.

[0032] Weigh 100 mg of LiTaOCl4 powder sample and press it into a solid disc with a diameter of 1 cm. Place the disc between two stainless steel rods and assemble it into a mold battery in a glove box filled with argon gas. Figure 2 The image shows the EIS curves of the corresponding battery tested in the frequency range of 0.1–100000 Hz and with a voltage amplitude of 5 mV. According to the formula for calculating ionic conductivity: σ = L / (R × A) (L: thickness; R: resistance; A: cross-sectional area), the ionic conductivity of the LiTaOCl4 material in Example 2 of this invention is 1.42 × 10⁻⁶. -2 S cm -1 .

[0033] Example 3

[0034] 2.151g of TaCl5 powder and 0.144g of LiOH powder were placed in an agate mortar and manually ground for 10 minutes. The ground powder was then transferred to a zirconia vacuum ball mill jar, and 30g of zirconia grinding beads with a diameter of 5mm were added. After sealing, the jar was ball-milled at 500 rpm for 40 hours in an argon-filled environment. After ball milling, the resulting amorphous LiTaOCl4 initial sample was collected, placed in a quartz tube, vacuum sealed, and heated to 300℃ in a tube furnace at a heating rate of 5℃ / min, and held for 3 hours. After the holding period, the vacuum quartz tube was immediately removed and immersed in a beaker containing liquid nitrogen. After cooling, it was heated again in the tube furnace at the same heating rate to 250℃, held for 2 hours, and after normal cooling, the product was ground to obtain LiTaOCl4 material. Its XRD pattern is shown below. Figure 1 .

[0035] Solid-state mold batteries were fabricated using the LiTaOCl4 material powder obtained in Example 3 according to the following method.

[0036] Weigh 100 mg of LiTaOCl4 powder sample and press it into a solid disc with a diameter of 1 cm. Place the disc between two stainless steel rods and assemble it into a mold battery in a glove box filled with argon gas. Figure 2 The image shows the EIS curves of the corresponding battery tested in the frequency range of 0.1–100000 Hz and with a voltage amplitude of 5 mV. According to the formula for calculating ionic conductivity: σ = L / (R × A) (L: thickness; R: resistance; A: cross-sectional area), the ionic conductivity of the LiTaOCl4 material in Example 3 of this invention is 1.00 × 10⁻⁶. -2 S cm -1 .

Claims

1. A method for preparing LiTaOCl4 material, characterized in that: The preparation method includes the following steps: Step 1: Amorphous LiTaOCl4 material was synthesized by solid-state ball milling using anhydrous LiOH and TaCl5 as raw materials. Step 2: Place the amorphous LiTaOCl4 material in a vacuum-sealed quartz tube, place the quartz tube in a tube furnace and heat it to 200-400℃ at a rate of 5-20℃ / min, hold it at that temperature for 150-300min, and then rapidly cool the quartz tube with liquid nitrogen. Step 3: Place the rapidly cooled quartz tube back into the tube furnace and heat it to 100-300℃ at a rate of 5-20℃ / min. Hold the temperature for 100-300min. After naturally cooling to room temperature, remove the product and grind it to obtain LiTaOCl4 material.

2. The preparation method according to claim 1, characterized in that: In step 2, the heating rate is 5-20℃ / min, and the temperature is maintained at 300℃ for 3 hours.

3. The preparation method according to claim 1, characterized in that: In step 3, the heating rate is 5-20℃ / min, and the temperature is heated to 150-250℃ and held for 2 hours.

4. The preparation method according to claim 3, characterized in that: In step 3, heat to 200℃ and keep warm for 2 hours.

5. The preparation method according to claim 1, characterized in that: The preparation method of the LiTaOCl4 material consists of steps 1 to 3.

6. A LiTaOCl4 material prepared by the preparation method according to any one of claims 1-5.

7. The application of the LiTaOCl4 material as described in claim 6 as a solid electrolyte in all-solid-state lithium batteries.

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