CN116826161A - Solid electrolyte and preparation method thereof, lithium-ion battery - Google Patents

Abstract

The present application relates to a solid electrolyte, a preparation method thereof, and a lithium-ion battery, and belongs to the technical field of lithium-ion batteries. A solid electrolyte, including a substrate and a metal source, the metal source is loaded on the surface of the substrate; the substrate includes a polymer electrolyte or an inorganic electrolyte; the metal source includes at least one of Li, In, Pt, Sn, Cu, Mg, Au and Zn kind. This application loads a suitable metal source, such as Li, In, Pt, Sn, Cu, Mg, Au and Zn, etc., on the surface of the substrate to form a thin metal layer on the surface of the substrate. This thin metal layer can make Li dendrites The morphology changes to spherical deposition, thereby reducing the degree of damage to the electrolyte and thereby improving the interface stability between the solid electrolyte and lithium metal.

Description

Solid electrolyte and preparation method thereof, lithium-ion battery

Technical field

The present application relates to the technical field of lithium-ion batteries, and in particular to a solid electrolyte and a preparation method thereof, and a lithium-ion battery.

Background technique

Solid electrolytes have excellent safety, stability, and mechanical properties in lithium-ion batteries, but there are currently some challenges. The reaction between the solid lithium ion electrolyte and lithium metal may lead to the deterioration of battery performance. This is mainly due to the irreversible chemical reaction between some solid electrolytes and lithium metal, producing by-products that have a negative impact on the battery. On the other hand, some solid-state electrolytes that are relatively stable to lithium metal may also be penetrated by lithium dendrites, causing battery short circuit; such as PEO-LISTFI, LLZO and Li ₂ OHBr, etc.

In order to improve the stability of the interface between solid electrolyte and lithium metal, composite electrolyte and surface interface modification are currently mainly used. Surface interface modification usually involves the in-situ or ex-situ formation of a protective layer on the interface between the electrolyte and lithium, such as alloys, inorganic ion conductors, etc. Composite electrolytes are mainly used in polymer electrolytes, such as adding fillers such as LLZTO to PEO-LISTFI. Composite inorganic electrolytes often rely on the melting or film-forming properties of the electrolyte. Furthermore, the composite electrolyte approach may degrade electrolyte properties such as mechanical properties and electrical conductivity.

In solid-state lithium-ion batteries, dendrites often form on the surface of the lithium anode, causing damage to the electrolyte interface. Traditional methods mainly protect the electrolyte by blocking dendrites, but cannot stabilize the electrolyte-lithium metal interface from the perspective of changing dendrite morphology. Some surface modification methods require higher equipment or material costs and more complex operations, such as using atomic layer deposition (ALD) to build an interface layer or sputtering noble metals such as Au and Pt on the electrolyte surface. Some reported electrolyte surface modification methods may significantly change the thickness and mass of the material, thereby reducing the energy density of the battery.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the embodiments of the present application includes providing a solid electrolyte to improve the stability of the interface between the solid electrolyte and lithium metal.

In a first aspect, embodiments of the present application provide a solid electrolyte, including a substrate and a metal source. The metal source is loaded on the surface of the substrate; the substrate includes a polymer electrolyte or an inorganic electrolyte; and the metal source includes Li, In, Pt, Sn, and Cu. , at least one of Mg, Au, Al and Zn.

This application loads a suitable metal source, such as Li, In, Pt, Sn, Cu, Mg, Au and Zn, etc., on the surface of the substrate to form a thin metal layer on the surface of the substrate. This thin metal layer can make Li dendrites The shape changes into spherical deposits. Since spherical Li deposition is more rounded and has no obvious sharp parts than columnar or mossy deposition, it causes less damage to the electrolyte or separator. Therefore, by loading a suitable metal source on the surface of the substrate to change the shape of Li dendrites into spherical deposition, the degree of damage to the electrolyte can be reduced, thereby improving the interface stability between the solid electrolyte and lithium metal, thereby improving the performance and reliability of the battery.

In some embodiments of the present application, the polymer electrolyte includes at least one of PEO-LISTFI, polyacrylonitrile, polyethyl acrylate, and polyvinyl alcohol.

In some embodiments of the present application, the inorganic electrolyte includes Li ₂ OHBr, Li ₃ N, Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₂ AlTi ₂ (PO4) ₃ , Li ₃ PS ₄ , Li ₂ B ₄ O ₇ and At least one of Li ₂ AlGe ₂ (PO ₄ ) ₃ .

In some embodiments of the present application, the substrate includes PEO-LISTFI electrolyte sheets or Li ₂ OHBr electrolyte sheets.

In some embodiments of this application, the preparation method of the PEO-LISTFI electrolyte sheet includes: dispersing PEO and LiTFSI in acetonitrile and stirring to obtain a mixed solution; pouring the mixed solution onto a silica gel sheet and drying to form a PEO-LISTFI electrolyte sheet .

In some embodiments of the present application, in PEO and LiTFSI, the molar ratio of EO units to lithium ions is (10-20):1. By setting the molar ratio of EO units to lithium ions in PEO and LiTFSI to (10-20):1, lithium ions can be well dissolved and transported in the electrolyte, thereby improving the ionic conductivity of the electrolyte.

In some embodiments of the present application, the stirring conditions include: the stirring temperature is 60-90°C, and the stirring time is 12-24 hours. Controlling the stirring temperature to 60-90°C and the stirring time to 12-24h can fully mix PEO and LiTFSI to form a uniform mixed solution, so that the polymer and lithium salt can be evenly distributed, thereby improving the uniformity and stability of the electrolyte. Consistency; also improves battery performance by improving the ionic conductivity of the electrolyte and reducing internal resistance.

In some embodiments of the present application, drying conditions include: drying temperature is 80-90°C, and drying time is 12-24 hours. Within this range of dry conditions, the formation of bubbles and pores in the electrolyte can be reduced, and the density and stability of the electrolyte can be improved.

In some embodiments of this application, the preparation method of Li ₂ OHBr electrolyte sheets includes: placing the starting materials LiOH and LiBr in a container, grinding the starting materials using zirconia balls to obtain powder; Carry out tableting and heat preservation treatments in sequence to obtain Li ₂ OHBr electrolyte tablets.

In some embodiments of the present application, the mass ratio of zirconia balls to starting materials is (10-40):1. Control the mass ratio of zirconia balls to starting materials to (10-40):1, so that it has sufficient mechanical energy transfer and grinding effect, thereby obtaining fine and uniform powder. The content of zirconia balls within this mass ratio range is more conducive to accelerating the grinding process, reducing the size of powder particles, and improving the uniformity and stability of the powder.

In some embodiments of the present application, the heat preservation treatment includes: the heat preservation temperature is 210-230°C, and the heat preservation time is 10-20 hours. Within the above temperature and time range, on the basis that the reaction is fully carried out, the reaction rate can be accelerated, the preparation time can be shortened, the production efficiency can be improved, and pure and uniform Li ₂ OHBr electrolyte sheets can be formed, making the structure and performance of the electrolyte sheets stable.

In a second aspect, embodiments of the present application provide a method for preparing the above-mentioned solid electrolyte, which includes: using magnetron sputtering technology to deposit a metal source on the surface of a substrate; wherein the sputtering gas includes argon; the sputtering power is 5-15W; sputtering time is 50-600s; sputtering pressure is 2-15Pa.

This preparation method uses magnetron sputtering technology to uniformly deposit a metal source on the surface of a substrate. During the preparation process, by controlling parameters such as the composition, power, time and pressure of the sputtering gas, the properties and properties of the deposited metal thin layer can be accurately controlled. Thickness enables precise control of solid electrolyte. Moreover, the preparation method is applicable to different types of electrolytes, including polymer electrolytes and inorganic electrolytes. This means that the most suitable electrolyte material can be selected according to specific application requirements and the corresponding solid electrolyte can be prepared. In short, this preparation method enables flexible preparation of different types of electrolytes, and has the advantages of high purity, high control accuracy, good film uniformity, and high preparation efficiency.

In a third aspect, embodiments of the present application provide a lithium-ion battery including the above-mentioned solid electrolyte.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a physical diagram of the original electrolyte and modified electrolyte in the embodiment of the present application;

Figure 2 is an SEM image of the solid electrolyte PEO-In in Example 1 of the present application;

Figure 3 is an SEM image of the solid electrolyte Li ₂ OHBr-In in Example 2 of the present application;

Figure 4 is a comparison chart of the cycle charge and discharge test results of lithium batteries made of PEO-In and PEO-LISTFI electrolyte sheets without sputtered metal sources provided in Example 1 of the present application;

Figure 5 is a comparison chart of the cycle charge and discharge test results of lithium batteries made of Li2OHBr-In and Li2OHBr electrolyte sheets without sputtered metal sources provided in Example 2 of the present application;

Figure 6 is a comparison chart of the test results of lithium batteries made of PEO-In and PEO-LISTFI electrolyte sheets without sputtered metal sources provided in Example 1 of the present application under different charging and discharging conditions;

Figure 7 is a comparison chart of the test results of lithium batteries made of Li2OHBr-In and Li2OHBr electrolyte sheets without sputtered metal sources provided in Example 2 of the application under different charging and discharging conditions;

Figure 8 is a comparison chart of the long cycle test voltage distribution of lithium batteries made of PEO-In and PEO-LISTFI electrolyte sheets without sputtered metal sources provided in Example 1 of the present application;

Figure 9 is a comparison chart of the long cycle test voltage distribution of lithium batteries made of Li2OHBr-In and Li2OHBr electrolyte sheets without sputtered metal sources provided in Example 2 of the present application;

Figure 10 is an SEM image of the solid electrolyte PEO-LISTFI without sputtered metal source provided in Comparative Example 5 of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

Solid-state lithium batteries use solid-state electrolytes, which have excellent performance in terms of safety, stability and mechanical properties. However, a large amount of solid-state lithium-ion electrolytes will react when interacting with Li metal, leading to the production of products that deteriorate battery performance, such as sulfides and halides, which have been hotly debated recently. On the other hand, for some solid-state electrolytes, although they are stable enough for Li metal, they may be penetrated by Li dendrites generated by Li deposition at the negative electrode during operation of lithium batteries or lithium-ion batteries, causing the battery to short circuit. . These solid electrolytes include PEO-LISTFI, LLZO, Li ₂ OHBr, etc.

The deposition forms of Li dendrites are generally divided into three types: columnar, mossy and spherical. Among them, columnar and mossy Li dendrites may penetrate the solid electrolyte and cause serious harm to solid-state batteries. The spherically deposited Li dendrites cause minimal damage to the electrolyte or separator, and have little impact on the performance of solid-state batteries. Solid-state lithium batteries face challenges in the matching between electrolyte and Li metal. It is necessary to find solid-state electrolyte materials that can simultaneously meet high safety, excellent stability, and good mechanical properties. Such an electrolyte can effectively suppress the occurrence of deterioration reactions and prevent Li dendrites from penetrating, thereby improving the performance and reliability of solid-state batteries.

The embodiments of the present application provide a solid electrolyte. The preparation of the solid electrolyte includes: using magnetron sputtering technology to remove metal sources such as Li, In, Pt, Sn, Cu, Mg, Au, Al and Zn in an argon environment. deposited on the surface of the substrate. Among them, the sputtering power is 5-15W; the sputtering time is 50-600s; the sputtering pressure is 2-15Pa. In the embodiment of the present application, the above-mentioned substrate includes polymer electrolyte or inorganic electrolyte, such as PEO-LISTFI, polyacrylonitrile, polyethyl acrylate, polyvinyl alcohol, Li ₂ OHBr, Li ₃ N, Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₂ AlTi ₂ (PO4) ₃ , Li ₃ PS ₄ , Li ₂ B ₄ O ₇ and at least one of Li ₂ AlGe ₂ (PO ₄ ) ₃ . The above-mentioned electrolyte can be selected as the substrate according to the actual situation, and this application does not limit this.

By adjusting the sputtering power to 5-15W, the sputtering time to 50-600s, and the sputtering pressure to 2-15Pa, the deposition amount of the metal source on the substrate surface and the thickness of the thin layer can be accurately controlled, so that the final result is covered with metal. The thickness of the thin layer of electrolyte is essentially the same as the thickness of the original electrolyte. The thickness of the metal thin layer formed by sputtering in this application is 100-500nm. That is to say, the thickness and quality of the electrolyte material will not be changed through the control of the above sputtering conditions, nor will the energy density of the battery be affected. In addition, under the above sputtering conditions, the metal source can be deposited uniformly and well combined with the substrate, thereby improving the stability of the interface between the solid electrolyte and lithium metal. This helps reduce reactions between the solid electrolyte and lithium metal, reducing battery performance degradation.

The embodiments of this application use PEO-LISTFI electrolyte sheets or Li ₂ OHBr electrolyte sheets as the substrate. Among them, the preparation method of PEO-LISTFI electrolyte sheet includes: dispersing PEO and LiTFSI (Macklin, 99%) in acetonitrile to obtain a mixture; in PEO and LiTFSI, the molar ratio of EO units to lithium ions is set to (10- 20):1; Then stir the mixture at 60-90°C for 12-24h until a uniform mixed solution is formed; then pour the mixed solution onto a silica gel sheet at 80°C, and then dry at 80-90°C for 12- 24h, and cut into discs with a diameter of 16mm to obtain PEO-LISTFI electrolyte sheets. The preparation method of Li ₂ OHBr electrolyte sheets includes: putting the starting materials LiOH (Aladdin, 98%) and LiBr (Macklin, 99%) into a 40mL zirconia tank, and using zirconia balls to grind the starting materials , to obtain powder; wherein, the mass ratio of zirconia balls to starting materials is (10-40):1; then the powder is pressed into discs with a diameter of 7mm and a thickness of 0.6mm and then kept at 210-230°C for 10 -20h to obtain Li ₂ OHBr electrolyte sheet. As an example, in PEO and LiTFSI, the molar ratio of EO units to lithium ions includes but is not limited to 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1 , 17:1, 18:1, 19:1, 20:1.

In the preparation of PEO-LISTFI electrolyte sheets, by controlling the molar ratio of EO units to lithium ions in PEO and LiTFSI and setting it to (10-20):1, on the one hand, the EO unit content within this ratio range can increase the polymer The flexibility and mobility of the chain are conducive to the movement of lithium ions; on the other hand, it can increase the stability and chemical resistance of the electrolyte. Therefore, by setting the molar ratio of EO units to lithium ions in PEO and LiTFSI to (10-20):1, lithium ions can be well dissolved and transported in the electrolyte, thereby improving the ionic conductivity of the electrolyte. Furthermore, controlling the stirring temperature to 60-90°C and the stirring time to 12-24h can fully mix PEO and LiTFSI to form a uniform mixed solution, so that the polymer and lithium salt can be evenly distributed, thereby improving the electrolyte performance. Uniformity and consistency; also improves battery performance by improving the ionic conductivity of the electrolyte and reducing internal resistance. Further, pour the mixed solution on a silica gel sheet at 80°C, and control the drying temperature to 80-90°C and the drying time to 12-24h. Within the above pouring and drying conditions, bubbles and pores in the electrolyte can be reduced. formation, improving the density and stability of the electrolyte. Moreover, using a silica gel sheet as the base can make the electrolyte sheet have better flatness and smoothness, which is beneficial to subsequent experiments and applications. Finally, it is cut into 16mm diameter discs to facilitate battery assembly and testing.

In the preparation of Li ₂ OHBr electrolyte sheets, the mass ratio of zirconia balls to starting materials is controlled to (10-40):1, so that it has sufficient mechanical energy transfer and grinding effect, thereby obtaining fine and uniform powder. body. The content of zirconia balls within this mass ratio range is more conducive to accelerating the grinding process, reducing the size of powder particles, and improving the uniformity and stability of the powder. Further, pressing the powder into discs with a diameter of 7 mm and a thickness of 0.6 mm is beneficial to forming consistent and regular electrolyte sheets. Within the above diameter and thickness range, the uniformity and stability of the electrolyte sheet can be improved, and the mechanical strength and durability of the electrolyte sheet can be improved, making it more suitable for practical application scenarios. In addition, the shape of the wafer facilitates subsequent battery assembly and testing. Furthermore, adjusting the holding temperature to 210-230°C and the holding time to 10-20 hours can promote the reaction, allowing LiOH and LiBr to react to form Li ₂ OHBr electrolyte. Within the above temperature and time range, on the basis that the reaction is fully carried out, the reaction rate can be accelerated, the preparation time can be shortened, the production efficiency can be improved, and pure and uniform Li ₂ OHBr electrolyte sheets can be formed, making the structure and performance of the electrolyte sheets stable.

Embodiments of the present application also provide a lithium-ion battery, including the above-mentioned solid electrolyte.

The features and performance of the present application will be described in further detail below in conjunction with examples.

Example 1

This embodiment provides a solid electrolyte, including the following preparation steps:

(1) Preparation of PEO-LISTFI electrolyte sheets

Disperse polyethylene oxide (PEO) and LiTFSI (Macklin, 99%) in acetonitrile to obtain a mixture. The molar ratio of EO units to lithium ions is set to 15:1, and the concentration of PEO in acetonitrile is 0.36g/mL. ; Stir the mixture in a sealed bottle at 85°C for 12h until a uniform solution is formed, then cast it on a silica gel sheet at 80°C, dry it at XX°C for XXh, and then cut it into discs with a diameter of 16mm. , that is, PEO-LISTFI electrolyte tablets are obtained.

(2) Sputtering metal source on PEO-LISTFI electrolyte sheet

Using magnetron sputtering technology in an argon environment, using In as the target material, In is sputtered onto the surface of the PEO-LISTFI electrolyte sheet to obtain PEO-In; the sputtering power is 10.5W; the sputtering time is 600s ;The sputtering pressure is 12Pa. The solid electrolyte after sputtering metallic In is shown in Figure 1.

Example 2

This embodiment provides a solid electrolyte, including the following preparation steps:

(1) Preparation of Li ₂ OHBr electrolyte sheets

Put the starting materials LiOH (Aladdin, 98%) and LiBr (Macklin, 99%) into a 40 mL zirconia tank, and use zirconia balls to grind the starting materials to obtain powder; wherein, zirconia balls and The mass ratio of the starting materials is 10:1; then the powder is pressed into a disc with a diameter of 7mm and a thickness of 0.6mm and then kept at 210°C for 12h to obtain a Li ₂ OHBr electrolyte sheet.

(2) Sputtering metal source on Li ₂ OHBr electrolyte sheet

Using magnetron sputtering technology in an argon environment, using In as the target material, In is sputtered onto the surface of the PEO-LISTFI electrolyte sheet to obtain Li ₂ OHBr-In; the sputtering power is 10.5W; the sputtering time is 600s; the sputtering pressure is 12Pa. The solid electrolyte after sputtering metallic In is shown in Figure 1.

Example 3

The PEO-LISTFI electrolyte sheets and Li ₂ OHBr electrolyte sheets used in Examples 3-16 were prepared using the same preparation method as in Example 1 and Example 2 above.

The difference between Examples 3-16 lies in the electrolyte sheet used and the metal source for sputtering. Please see Table 1 for details.

Table 1

Group electrolyte tablets metal source Group electrolyte tablets metal source Example 3 PEO-LISTFI Pt Example 10 Li ₂ OHBr Pt Example 4 PEO-LISTFI Sn Example 11 Li ₂ OHBr Sn Example 5 PEO-LISTFI Cu Example 12 Li ₂ OHBr Cu Example 6 PEO-LISTFI Mg Example 13 Li ₂ OHBr Mg Example 7 PEO-LISTFI Au Example 14 Li ₂ OHBr Au Example 8 PEO-LISTFI Zn Example 15 Li ₂ OHBr Zn Example 9 PEO-LISTFI Ag, Al Example 16 Li ₂ OHBr Ag, Al

Example 17

This embodiment is basically the same as Embodiment 1, except that the sputtering time is 50 seconds.

Example 18

This embodiment is basically the same as Embodiment 1, except that the sputtering time is 300 s.

Comparative example 1

This comparative example is basically the same as Example 1, except that the sputtering time is 40 seconds.

Comparative example 2

This comparative example is basically the same as Example 1, except that the sputtering time is 700 s.

Comparative example 3

This comparative example is basically the same as Example 1, except that the sputtered metal is Fe.

Comparative example 4

This comparative example is basically the same as Example 1, except that the sputtered metal is Pd.

Comparative example 5

This comparative example is basically the same as Example 1, except that no metal is sputtered.

Test example 1

In this test example, the solid electrolytes provided in Example 1, Example 2, and Comparative Example 5 were characterized by SEM. The test results are shown in Figures 2, 3, and 10. Figure 2 shows the PEO-In surface provided in Example 1. Li deposition state. Figure 3 shows the Li deposition state on the surface of Li ₂ OHBr-In provided in Example 2. Figure 10 shows the Li deposition state on the surface of solid electrolyte PEO-LISTFI provided in Comparative Example 5.

As can be seen from Figures 2 and 3, spherical Li deposition appears on the surfaces of both PEO-In and Li ₂ OHBr-In. It can be seen from Figure 10 that when PEO-LISTFI does not sputter any metal, the surface of PEO-LISTFI has mossy deposits.

Test example 2

In this test example, the solid electrolytes provided in Examples 1-16 and Comparative Examples 1-5 were used to prepare corresponding batteries, and the electrochemical properties of the above batteries were tested, including:

1. First cycle discharge specific capacity measurement: discharge gram capacity at 0.2C (1C=170mA/g) to the lower limit voltage.

2. Coulombic efficiency: (each cycle) first discharge capacity/first charge capacity.

The test results of the above items are shown in Table 2.

Table 2

Group First cycle discharge specific capacity (mAh/g) Coulomb efficiency (%) Example 1 159.8 96.65 Example 2 142.1 93.42 Example 3 155.2 95.85 Example 4 146.5 93.10 Example 5 150.2 95.10 Example 6 148.5 94.81 Example 7 154.0 95.22 Example 8 145.2 92.89 Example 9 155.5 95.8 Example 10 138.4 92.10 Example 11 125.9 90.12 Example 12 132.6 91.01 Example 13 129.2 90.86 Example 14 136.2 91.05 Example 15 126.8 89.6 Example 16 137.9 91.89 Comparative example 1 130.1 95.01 Comparative example 2 132.3 94.22 Comparative example 3 123.2 84.2 Comparative example 4 129.5 85.5 Comparative example 5 107.7 94.96

By comparing Examples 1, 17-18 and Comparative Examples 1-2, it can be seen that when the sputtering time is 50-600s, the effect of the full battery assembled from the solid electrolyte is better; the sputtering time is too short, and the metal infiltration Poor performance, resulting in low specific capacity and Coulombic efficiency of the battery; too long sputtering time and large metal layer thickness will affect battery performance and reduce specific capacity and Coulombic efficiency.

By comparing Example 1, Comparative Example 3 and Comparative Example 4, the sputtered metals are Fe and Pt respectively. It can be seen that the discharge capacity and Coulombic efficiency of the first cycle are both lower than In. By comparing Examples 1-9 and Comparative Example 5, it can be seen that after the metal source defined in this application is sputtered on the surface of the PEO-LISTFI electrolyte sheet, the electrochemical performance of the assembled battery is better.

Test example 3

This test example uses the solid electrolytes provided in Example 1 and Example 2 as well as Li ₂ OHBr electrolyte sheets and PEO-LISTFI electrolyte sheets without sputtered metal sources to prepare corresponding lithium batteries. The above batteries are subjected to the following electrochemical performance tests:

1. Cyclic charge and discharge test, use 0.2C (1C=170mA/g) for charge and discharge in the first five cycles, and use 0.5C for the rest. The cycle charge and discharge performance diagrams shown in Figure 4 and Figure 5 are obtained. Figure 4 is a comparison chart of the cycle charge and discharge test results of lithium batteries made of PEO-In and PEO-LISTFI electrolyte sheets without sputtered metal sources provided in Example 1;

Figure 5 is a comparative chart of cycle charge and discharge test results of lithium batteries made of Li ₂ OHBr-In and Li ₂ OHBr electrolyte sheets without sputtered metal sources provided in Example 2.

2. Test under different charging and discharging conditions, that is, start charging and discharging for 30 minutes each from a current density of 0mA/ ^cm2 , and then increase the critical current or limit current density by increasing 0.1mA/ ^cm2 per hour (each cycle). (CCD) test, the CCD test comparison chart shown in Figure 6 and Figure 7 is obtained. Figure 6 is a comparison chart of the test results of lithium batteries made of PEO-In and PEO-LISTFI electrolyte sheets without sputtered metal sources provided in Example 1 under different charging and discharging conditions; Figure 7 is a comparison of Li provided in Example 2 Comparison of the test results of lithium batteries made of ₂ OHBr-In and Li ₂ OHBr electrolyte sheets without sputtered metal sources under different charge and discharge conditions.

3. The long cycle test voltage distribution of charging and discharging at 0.1mA/ ^cm2 for 30 minutes each. The test results are shown in Figures 8 and 9. Figure 8 is a comparison chart of the long cycle test voltage distribution of lithium batteries made of PEO-In provided in Example 1 and PEO-LISTFI electrolyte sheets without sputtered metal sources; Figure 9 is a comparison chart of Li ₂ OHBr-In provided in Example 2 Comparison of the long-cycle test voltage distribution of lithium batteries made from Li ₂ OHBr electrolyte sheets without sputtered metal sources.

In Figures 4 and 5, LFP/PEO/Li is a lithium battery assembled from the original PEO-LISTFI electrolyte sheets, and LFP/PEO-In/Li is a lithium battery assembled from the solid electrolyte PEO-In provided in Example 1. LFP/Li ₂ OHBr/Li is a lithium battery assembled from original Li ₂ OHBr electrolyte sheets, and LFP/Li ₂ OHBr-In/Li is a lithium battery assembled from the solid electrolyte Li ₂ OHBr-In provided in Example 2. As can be seen from Figure 4, the first-cycle discharge specific capacities of LFP/PEO/Li and LFP/PEO-In/Li are 107.7mAh/g and 159.8mAh/g respectively, and the Coulombic efficiencies are 94.96% and 96.65% respectively; After nearly 30 charge and discharge cycles, the Coulombic efficiency of LFP/PEO/Li dropped sharply. At the 40th cycle, the discharge specific capacity of LFP/PEO/Li was 149.2mAh/g, and the Coulombic efficiency was 77.78, while LFP/PEO The specific capacity of -In/Li in the 40th cycle is 153.7mAh/g and the Coulombic efficiency is 99.99%. Until the 155th cycle, LFP/PEO/Li and LFP/PEO-In/Li can contribute 101mAh/g and 139.3mAh/ respectively. g specific capacity. In addition, as shown in Figure 5, the cycle charge and discharge test results of LFP/Li ₂ OHBr/Li and LFP/Li ₂ OHBr-In/Li also show great differences. When the first cycle charge specific capacity is the same, the two The discharge capacities of LFP/Li 2 OHBr/Li were 137.6mAh/g and 142.1mAh/g respectively. During the subsequent charge and discharge process, LFP/Li ₂ OHBr/Li showed poor cycle performance. Its capacity dropped sharply after 25 cycles until 29 cycles. The battery has expired, but LFP/Li ₂ OHBr-In/Li has the ability to cycle stably for more than 50 cycles.

It can be seen from Figures 6 and 7 that the lithium batteries prepared by PEO-In and Li ₂ OHBr-In provided in Example 1 and Example 2 respectively did not short-circuit until 0.7mA/cm ² , while those without sputtered metal sources Lithium batteries prepared from Li ₂ OHBr electrolyte sheets and PEO-LISTFI electrolyte sheets experienced short circuit at 0.5 mA/cm ² , indicating that sputtering In on solid electrolytes can greatly improve the material's high current withstand capability.

In Figures 8 and 9, the long cycle test of symmetrical lithium batteries using PEO-LISTFI and Li ₂ OHBr as electrolytes was conducted at 60°C and 100°C respectively. The purpose is to ensure that the multi-electrolyte surface can be observed while charging and discharging the battery within the normal voltage range. Li deposition form. As can be seen from Figures 8 and 9, lithium batteries prepared with exposed PEO-LISTFI electrolyte sheets and Li ₂ OHBr electrolyte sheets were penetrated by lithium dendrites after cycling for 195h and 221h respectively, causing the voltage to drop close to 0V. Short circuit; while lithium batteries prepared from PEO-In and Li ₂ OHBr-In sputtered with In remain stable after 2000 hours of continuous charge and discharge cycles.

The above-described embodiments are part of the embodiments of the present application, but not all of the embodiments. The detailed description of the embodiments of the application is not intended to limit the scope of the application as claimed, but rather to represent selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

Claims (10)

1. A solid electrolyte, characterized in that it includes a substrate and a metal source, and the metal source is loaded on the surface of the substrate; The substrate includes a polymer electrolyte or an inorganic electrolyte; The metal source includes at least one of Li, In, Pt, Sn, Cu, Mg, Au, Al and Zn. 2. The solid electrolyte according to claim 1, wherein the polymer electrolyte includes at least one of PEO-LISTFI, polyacrylonitrile, polyethyl acrylate and polyvinyl alcohol. 3. The solid electrolyte according to claim 2, characterized in that the inorganic electrolyte includes Li ₂ OHBr, Li ₃ N, Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₂ AlTi ₂ (PO4) ₃ , Li ₃ PS _4. At least one of Li ₂ B ₄ O ₇ and Li ₂ AlGe ₂ (PO ₄ ) ₃ . 4. The solid electrolyte according to claim 3, wherein the substrate includes a PEO-LISTFI electrolyte sheet or a Li ₂ OHBr electrolyte sheet. 5. The solid electrolyte according to claim 4, wherein the preparation method of the PEO-LISTFI electrolyte sheet includes: Disperse PEO and LiTFSI in acetonitrile and stir to obtain a mixed solution; pour the mixed solution onto a silica gel sheet and dry to form the PEO-LISTFI electrolyte sheet. 6. The solid electrolyte according to claim 5, wherein in the PEO and the LiTFSI, the molar ratio of EO units to lithium ions is (10-20): 1; Preferably, the stirring conditions include: the stirring temperature is 60-90°C, and the stirring time is 12-24 hours; Preferably, the drying conditions include: drying temperature is 80-90°C, and drying time is 12-24 hours. 7. The solid electrolyte according to claim 4, characterized in that the preparation method of the Li ₂ OHBr electrolyte sheet includes: placing starting materials LiOH and LiBr in a container, using zirconia balls to clean the starting materials Grind to obtain powder; perform tableting and heat preservation treatment on the powder in sequence to obtain the Li ₂ OHBr electrolyte tablet. 8. The solid electrolyte according to claim 7, wherein the mass ratio of the zirconia balls to the starting material is (10-40): 1; Preferably, the heat preservation treatment includes: a heat preservation temperature of 210-230°C and a heat preservation time of 10-20 hours. 9. A method for preparing a solid electrolyte according to any one of claims 1 to 8, characterized in that it includes: depositing a metal source on the surface of the substrate using magnetron sputtering technology; Among them, the sputtering gas includes argon; the sputtering power is 5-15W; the sputtering time is 50-600s; and the sputtering pressure is 2-15Pa. 10. A lithium ion battery, characterized by comprising the solid electrolyte according to any one of claims 1 to 8.