High-conductivity cuprous halide doped chlorine-rich argyrodite electrolyte as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of materials, and particularly relates to a high-conductivity cuprous halide doped chlorine-rich argyrodite electrolyte as well as a preparation method and application thereof. The preparation method comprises the following steps: putting raw materials Li2S, P2S5, LiCl and CuX (X = F, Cl, Br and I) into a high-speed ball mill according to a certain proportion, uniformly mixing, and after ball milling is completed, pressing an electrolyte powder precursor into blocks under a certain pressure (10-1000 Mpa); sealing in a vacuum quartz tube for subsequent annealing treatment, and grinding the blocky electrolyte subjected to annealing treatment in a mortar to obtain the final electrolyte marked as LPSI-(CuX) z. The method is simple in process, low in cost, good in reproducibility and excellent in performance.

Description

Technical Field

[0001] The invention belongs to the technical field of materials, and in particular relates to a high-conductivity cuprous halide-doped chlorine-rich argyrodite electrolyte, a preparation method and an application thereof. Background Art

[0002] In the early 1990s, Sony first discovered and developed a lithium battery with carbon material as the negative electrode and LiCoO2 as the positive electrode. During the charging and discharging process of this battery, there is no metallic lithium, only lithium ions, which is also called a lithium-ion battery. With the development of technology, the energy density of lithium-ion batteries has been much higher than that of the original lithium-ion batteries, and its application range is becoming more and more extensive, but with it comes more safety hazards. Commercial lithium-ion batteries use liquid organic electrolytes and graphite negative electrodes, which have safety hazards and low energy density, becoming a problem that needs to be solved urgently. On the other hand, the use of high-conductivity inorganic solid electrolytes in solid-state batteries can not only solve the safety problems of traditional lithium-ion batteries, but also increase the energy density of the battery, which is expected to solve the range anxiety of electric vehicles. Summary of the invention

[0003] The present invention aims to provide a cuprous halide doped electrolyte, a preparation method and application in a solid-state lithium battery. The method has simple process, low cost, good reproducibility and excellent performance.

[0004] To achieve the above object, the present invention adopts the following technical solution: The synthesis of the cuprous halide doped electrolyte comprises the following steps: (1) The raw materials Li2S, P2S5, LiCl and CuX (X = F, Cl, Br, I) are mixed in a certain proportion of the molecular formula Li 5.4- x PS 4.4 Cl 1.6-x (CuX) Z Ratio, Z=0~1, mixed evenly in a high-speed ball mill, the ball milling time is 2-48h; (2) After ball milling, the electrolyte powder precursor is pressed into a block under a certain pressure (10 MPa-1000 MPa); (3) The block is then sealed in a vacuum quartz tube for subsequent annealing at a temperature of 100°C-1000°C for a time of 1h-168h. The annealed block electrolyte is ground in a mortar to obtain the final electrolyte, which is recorded as LPSCl-(CuX) z .

[0005] Assembly of the full battery: The positive electrode, the obtained electrolyte and the conductive carbon are mixed in a certain proportion and ground in a mortar to obtain a positive electrode composite material. The full battery uses the above positive electrode composite material as the positive electrode and the lithium indium alloy as the negative electrode to form a full battery with the above prepared electrolyte.

[0006] The significant advantages of the present invention are: Simple doping not only improves the ionic conductivity but also reduces the particle size of the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 - is the XRD pattern of the two prepared electrolyte materials; Figure 2 is the electrolyte impedance diagram; Figure 3 This is a scanning electron microscope image of the electrolyte before doping; Figure 4 This is a scanning electron microscope image of the electrolyte after doping; Figure 5 is the cycle performance diagram. DETAILED DESCRIPTION

[0008] In order to further disclose but not limit the present invention, the present invention is further described in detail below with reference to examples.

[0009] Example 1 The synthesis of the cuprous halide doped electrolyte comprises the following steps: (1) The raw materials Li2S, P2S5, LiCl and CuX (X = F, Cl, Br, I) are mixed in a certain proportion of the molecular formula Li 5.4- x PS 4.4 Cl 1.6-x (CuX) Z Ratio, Z=0~1, placed in a high-speed ball mill and mixed evenly, the ball milling time is 2-48h; (2) After ball milling, the electrolyte powder precursor is pressed into a block under a certain pressure (10 MPa-1000 MPa); (3) The block is then sealed in a vacuum quartz tube for subsequent annealing at 510°C for ten hours. The annealed block electrolyte is ground in a mortar to obtain the final electrolyte, which is recorded as LPSCl-(CuX) z .

[0010] Assembly of the full battery: The positive electrode, the obtained electrolyte and the conductive carbon were mixed in a certain mass ratio of 50:45:5, and the positive electrode composite material was obtained by grinding in a mortar. The full battery used the above positive electrode composite material as the positive electrode and the lithium indium alloy as the negative electrode, and the above prepared electrolyte to form a full battery.

[0011] Figure 1 The XRD diagram of the material is shown in the figure. Figure 2 is the impedance diagram, Figure 3 and Figure 4 It is a scanning electron microscope. The chlorine-rich phase of the argyrodite electrolyte is prone to lithium chloride impurities. Figure 1 The peak in the middle box corresponds to the impurity peak of lithium chloride. In the electrolyte after copper halide replacement doping, the peak of lithium chloride is reduced or disappeared. In addition, cuprous ions are close to the radius of lithium ions and can partially replace lithium, thereby improving the ionic conductivity of the electrolyte. From the scanning electron microscope image, it can be seen that the material presents a block-like particle morphology. The particle size before doping is about 5-10um, and the particle size after doping is about 3-5um. This proves that the doping of cuprous halide can reduce the particle size of the electrolyte. Figure 5 : This is a cycle performance diagram of the NCM811 half-cell assembled with the electrolyte. It can be seen that the cycle performance of the NCM811 half-cell is excellent, proving that this electrolyte has certain applicability.

[0012] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a high-conductivity cuprous halide-doped chlorine-sulfur-rich argyrogermanite electrolyte, characterized in that: The following steps are involved: (1) The raw materials Li2S, P2S5, LiCl and CuX are mixed according to the molecular formula Li 5.4-x PS 4.4 Cl 1.6-x (CuX) Z Ratio, Z = 0~1, placed in a high-speed ball mill and mixed evenly, X is any one of F, Cl, Br, I; (2) After ball milling, the electrolyte powder precursor is pressed into a block under a certain pressure; (3) The block is then sealed in a vacuum quartz tube for subsequent annealing. The annealed block electrolyte is ground in a mortar to obtain the final electrolyte, which is recorded as LPSCl-(CuX) z , z=0~1.

2. The cuprous halide-doped argyrodite electrolyte according to claim 1, characterized in that: The ball milling time in step (1) is 2-48 hours.

3. The cuprous halide-doped chlorine-rich argyrodite electrolyte according to claim 1, characterized in that: The pressure in step (2) is 10 MPa-1000 MPa.

4. The cuprous halide doped chlorine-rich argyrodite electrolyte according to claim 1, characterized in that: The annealing conditions of step (3) are: annealing temperature is 100°C-1000°C, and annealing time is 1h-168h.

5. The cuprous halide-doped argyrogermanite electrolyte obtained by the preparation method according to any one of claims 1 to 4.

6. Application of the cuprous halide doped chlorine-rich argyrodite electrolyte as claimed in claim 5 in a solid-state lithium battery.

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