Synthesis method of low-cost chlorine-rich argyrodite electrolyte

Abstract

The invention provides a low-cost synthesis method of a chlorine-rich argyrodite electrolyte. Raw materials Li2O, P2S5 and LiCl are placed in a high-speed ball mill according to a certain proportion to be evenly mixed, the ball milling time is 2-48 h, after ball milling is completed, an electrolyte powder precursor is pressed into blocks under a certain pressure (10-1000 Mpa), then the blocks are sealed in a vacuum quartz tube to be subjected to follow-up annealing treatment, and the electrolyte powder is obtained. And grinding the blocky electrolyte subjected to annealing treatment in a mortar to obtain the final electrolyte marked as Li < 6-x > PS2 < 2.5 > O < 2.5-x > Cl < 1 + x >. The invention provides a low-cost chlorine-rich argyrodite electrolyte and application thereof in a solid-state lithium battery. The method is simple in process, low in cost, good in reproducibility and excellent in performance.

Description

Technical Field

[0001] This invention belongs to the field of solid electrolytes, specifically relating to a low-cost method for synthesizing a chloride-rich silver-germanium ore electrolyte. Background Technology

[0002] In the early 1990s, Sony first discovered and developed a lithium-ion battery using carbon materials as the negative electrode and LiCoO2 as the positive electrode. During charging and discharging, no metallic lithium is present; only lithium ions are present, hence the name lithium-ion battery. With technological advancements, the energy density of lithium-ion batteries has significantly improved compared to the original models, and their applications have become increasingly widespread. However, this has also brought more safety concerns. Commercial lithium-ion batteries use liquid organic electrolytes and graphite negative electrodes, which present safety risks and low energy density issues, becoming pressing problems to be solved. On the other hand, solid-state batteries, using highly conductive inorganic solid electrolytes, can not only solve the safety problems of traditional lithium-ion batteries but also improve battery energy density, potentially alleviating range anxiety in electric vehicles.

[0003] There are currently no reports on the use of lithium sources to replace expensive lithium sulfide in the preparation of silver-germanium sulfide electrolytes and their application in solid-state lithium batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a low-cost synthesis method for a chloride-rich silver-germanium ore electrolyte.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A low-cost method for synthesizing a chloride-rich silver-germanium ore electrolyte includes the following steps: The raw materials Li₂O, P₂S₅, and LiCl were prepared according to the molecular formula Li 6-x PS 2.5 O 2.5-x Cl 1+x x=0-1, and the mixture is prepared by proportioning and placed in a high-speed ball mill for uniform mixing. After ball milling, the obtained electrolyte powder precursor is pressed into blocks under a certain pressure, and then sealed in a vacuum quartz tube for subsequent annealing. The annealed block electrolyte is then ground in a mortar to obtain the chloride-sulfur silver-germanium ore electrolyte Li. 6-x PS 2.5 O 2.5-x Cl 1+x .

[0006] Furthermore, the ball milling speed is 500-2000 rpm, and the ball milling time is 2-48 hours.

[0007] Furthermore, the pressure is 10 MPa-1000 MPa.

[0008] Furthermore, the annealing temperature is 100-900℃, and the time is 2-200h.

[0009] Furthermore, the chloride-rich silver-germanium ore electrolyte was obtained by the method described above.

[0010] Furthermore, the application of the aforementioned chloride-rich silver-germanium ore electrolyte in solid-state lithium batteries.

[0011] The advantages of this invention are: This invention provides a low-cost chloride-sulfur silver-germanium ore electrolyte and its application in solid-state lithium batteries. The method is simple, inexpensive, reproducible, and has excellent performance. Attached Figure Description

[0012] Figure 1 XRD pattern of the material; Figure 2 Impedance diagram of the material; Figure 3 For Li 5.3 PS 2.5 O 1.8 Cl 1.7 Scanning electron microscope image of the material; Figure 4 For Li 5.3 PS 4.3 Cl 1.7 Scanning electron microscope image of the material; Figure 5 The circuit performance diagram of the NCM811 half-cell is shown. Figure 6 The graph shows the cycle performance of the NCM811 half-cell. Detailed Implementation

[0013] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are provided below for detailed description. Unless otherwise specified, the methods of the present invention are conventional methods in the art.

[0014] Example 1 Synthesis of electrolyte materials: The raw materials Li₂O, P₂S₅, and LiCl are synthesized according to the chemical formula Li 5.3 PS 2.5 O 1.8 Cl 1.7 The mixture was prepared according to the specified proportions and placed in a high-speed ball mill for 2 hours. After ball milling, the electrolyte powder precursor was pressed into blocks under a pressure of 10 MPa and then sealed in a vacuum quartz tube for subsequent annealing at 500℃ for 6 hours. The annealed electrolyte blocks were then ground in a mortar to obtain the final electrolyte, denoted as Li. 5.3 PS 2.5 O 1.8Cl 1.7 .

[0015] Assembly of the full cell: The positive electrode, the obtained electrolyte, and conductive carbon were mixed in a mass ratio of 65:30:5 and ground in a mortar to obtain a positive electrode composite material. The full cell uses the above-mentioned positive electrode composite material as the positive electrode and a lithium-indium alloy as the negative electrode, together with the electrolyte prepared above, to form a full cell.

[0016] Figure 1 This is the XRD pattern of the material. The chloride-rich phase of the silver-germanium sulfide electrolyte Li... 5.3 PS 4.3 Cl 1.7 Lithium chloride impurities are prone to appear, and the chlorine-rich silver-germanium ore electrolyte prepared by using Li2O instead of Li2S as a raw material has higher crystallinity. Figure 2 This is the impedance diagram of the material. When using Li2O to replace Li2S as a raw material, on the one hand, the cost of raw materials can be significantly reduced, and on the other hand, oxygen ions and sulfur ions belong to the same group, so oxygen can partially replace sulfur, and the conductivity can be maintained without a significant decrease.

[0017] Figure 3 and Figure 4 These are scanning electron microscope (SEM) images of the materials. The SEM images show that the materials exhibit a bulky particle morphology. The particle size of the material prepared using Li₂S is approximately 10-20 μm, while the particle size of the material prepared using Li₂O is approximately 3-5 μm. This demonstrates that the particle size of the electrolyte has been reduced.

[0018] Figure 5 and Figure 6 This is a cycle performance graph for an NCM811 half-cell. It shows the performance using Li... 5.3 PS 2.5 O 1.8 Cl 1.7 The assembled half-cell achieved 173.3 mA hg at a current of 0.1 C. −1 It exhibits a high initial discharge capacity and retains 82.8% of its capacity after 80 cycles. This performance surpasses that of materials using Li. 5.3 PS 4.3 Cl 1.7 The control cell for the electrolyte only provided 161.8 mA hg. −1 The initial capacity is low, with a capacity retention of only 76.5%, and coulombic efficiency instability occurs after 60 cycles. This demonstrates the limitations of using Li. 5.3 PS 2.5 O 1.8 Cl 1.7 The assembled NCM811 half-cell exhibited excellent cycle performance, demonstrating the applicability of this electrolyte.

[0019] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A low-cost method for synthesizing a chloride-rich silver-germanium ore electrolyte, characterized in that, Includes the following steps: The raw materials Li₂O, P₂S₅, and LiCl were prepared according to the molecular formula Li 6-x PS 2.5 O 2.5-x Cl 1+x x=0-1, and the mixture is prepared by proportioning and placed in a high-speed ball mill for uniform mixing. After ball milling, the obtained electrolyte powder precursor is pressed into blocks under a certain pressure, and then sealed in a vacuum quartz tube for subsequent annealing. The annealed block electrolyte is then ground in a mortar to obtain the chloride-sulfur silver-germanium ore electrolyte Li. 6-x PS 2.5 O 2.5-x Cl 1+x .

2. The method according to claim 1, characterized in that, The ball mill speed is 500-2000 rpm.

3. The method according to claim 1, characterized in that, The ball milling time is 2-48 hours.

4. The method according to claim 1, characterized in that, The pressure is 10 MPa-1000 Mpa.

5. The method according to claim 1, characterized in that, The annealing temperature is 100-900℃ and the time is 2-200h.

6. The chloride-rich silver-germanium ore electrolyte obtained by the method according to any one of claims 1-5.

7. The application of the chloride-rich silver germanium ore electrolyte as described in claim 6 in solid-state lithium batteries.

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