Preparation method of electrolyte, negative electrode and current collector integrated structure of lithium solid-state battery

Abstract

The invention discloses a preparation method of an electrolyte, negative electrode and current collector integrated structure of a lithium solid-state battery, and belongs to the technical field of lithium ion batteries. The method comprises the following steps: coating a negative electrode with a lithium solid-state battery electrolyte solution with the thickness of 100-500 microns, and carrying out vacuum drying in a vacuum oven at 80 DEG C for 12 hours to obtain a lithium solid-state battery electrolyte, negative electrode and current collector integrated structure; the electrolyte solution, the negative electrode and the current collector all contain two-dimensional materials. According to the lithium solid-state battery electrolyte provided by the invention, a two-dimensional material additive is added into a commercial solid-state electrolyte, so that the mechanical property and the ionic conductivity of the electrolyte are effectively improved. According to the lithium solid-state battery electrolyte, the negative electrode and the current collector integrated structure prepared by the invention, the problem of poor rate capability of a traditional graphite negative electrode material can be effectively improved, and a high-rate lithium solid-state battery can be realized due to a firm and stable lithium ion transmission path and interface performance of the lithium solid-state battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and in particular relates to a method for preparing an integrated structure of a lithium solid-state battery electrolyte, a negative electrode and a current collector. Background Art

[0002] Compared to lithium-ion batteries, all-solid-state batteries offer advantages in safety, energy density, lifespan, and fast charging. Commercial liquid lithium batteries currently suffer from low energy density and poor safety, causing widespread concern. In contrast, all-solid-state batteries offer both high safety and high energy density, making them an inevitable trend in energy transition. Solid-state electrolytes, as carriers for ion transport, have been extensively researched, and developing solid-state electrolytes with excellent mechanical and electrochemical properties is key to achieving high-performance all-solid-state batteries.

[0003] MXenes exhibit a range of remarkable properties due to their unique structure and tunable surface chemical functional groups. Their application in electrochemical energy storage has garnered particular attention, particularly for supercapacitor applications. MXenes possess excellent mechanical flexibility, energy density, and electrochemical performance, making them particularly suitable electrode materials for supercapacitors.

[0004] At present, the research on solid electrolytes is mainly divided into inorganic solid electrolytes and polymer solid electrolytes. Inorganic solid electrolytes have large electrode interface impedance and immature processing technology, and there are still many limitations in their application areas. Polymer solid electrolytes have good contact with the electrode interface and are easy to process, which has obvious advantages in realizing the industrialization of high-energy-density solid-state lithium batteries. Compared with polyethylene oxide (PEO), polyacrylonitrile (PAN), polycarbonate (PC), and polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF) and polyvinylidene fluoride hexafluoropropylene copolymer (PVDF-HFP) materials have better dielectric constants, chemical stability and higher mechanical strength, making them more suitable as research objects for solid electrolytes for lithium batteries.

[0005] Graphite is currently the most widely used negative electrode material for lithium batteries. It stores lithium ions through a layered structure and has high safety and stability. The theoretical specific capacity of graphite negative electrodes is about 372mAh / g, and the actual reversible specific capacity has reached 340-360mAh / g. However, graphite negative electrodes are prone to producing lithium dendrites under fast charging conditions, affecting the safety and cycle performance of the battery. At the same time, although the theoretical specific capacity of silicon negative electrodes is extremely high, they still have disadvantages such as severe volume expansion, poor conductivity, low initial charge and discharge efficiency, difficult processing, poor low-temperature performance, and easy collapse and deformation.

[0006] Copper foil is the primary material for battery anode current collectors due to its excellent conductivity, soft texture, and high stability. However, copper's high density also affects the battery's energy density. While polymer-composite copper foil can effectively address this problem, existing technology is still immature. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems of low energy density of existing lithium-ion batteries, low theoretical specific capacity of existing graphite negative electrodes, easy collapse and deformation of silicon negative electrodes, poor interface performance and mechanical properties of existing solid-state electrolytes, poor cycle stability and rate performance of existing solid-state batteries, and high impedance of existing solid-state batteries. A method for preparing an integrated structure of lithium solid-state battery electrolyte, negative electrode and current collector is provided, which improves the safety performance, energy density and mechanical properties of the battery.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, comprising: coating a lithium solid-state battery electrolyte solution on the negative electrode with a thickness of 100-500 μm in a glove box, and vacuum drying the solution at 80° C. in a vacuum oven for 12 hours to obtain an integrated structure of the lithium solid-state battery electrolyte, negative electrode and current collector; the electrolyte solution, negative electrode and current collector all contain two-dimensional materials.

[0010] Furthermore, the two-dimensional material is one or more of MXene (Ti3C2), graphene, silicene, germanene, molybdenum disulfide (MoS2), two-dimensional graphitic carbon nitride (g-C3N4), layered double hydroxides (LDHs), boron nitride (BN), covalent organic frameworks (COFs) or titanium nitride (Ti2N).

[0011] Furthermore, the specific steps of preparing the negative electrode are:

[0012] Step 1: Add the dense two-dimensional material as the negative electrode active material, a binder, and a conductive agent in a mass ratio of 6:3:1 into 2.5 ml of N-methylpyrrolidone (NMP), and stir at room temperature for more than 24 hours to obtain a two-dimensional material negative electrode solution;

[0013] Step 2: Apply the two-dimensional material negative electrode solution to a thickness of 200 μm on the two-dimensional material negative electrode current collector, and dry it in a vacuum oven at 80° C. for 12 hours to obtain a lithium solid-state battery negative electrode.

[0014] Furthermore, in step 1, the adhesive has a molecular weight of 1.1×10 6 The conductive agent is conductive carbon black (SuperP).

[0015] Furthermore, in step 2, the two-dimensional material negative electrode current collector is a 95 vol% two-dimensional material aqueous dispersion that is centrifuged, and a large sheet of two-dimensional material with better bottom conductivity and mechanical properties is coated on a glass plate with 500 nm to obtain a high-quality two-dimensional material negative electrode current collector.

[0016] Furthermore, the preparation method of the electrolyte solution comprises the following steps:

[0017] Step 1: Place the lithium salt in a vacuum oven and dry it for one week, wherein the vacuum oven temperature is set to 50-80°C;

[0018] Step 2: placing the dried lithium salt obtained in step 1 into a glove box; wherein the water and oxygen values ​​in the glove box are all less than 0.01 ppm;

[0019] Step 3: In a glove box, dissolve the solid-state battery polymer material in an aprotic polar solvent and stir at room temperature for 6 hours to obtain a polymer electrolyte solution;

[0020] Step 4: In a glove box, add the two-dimensional material additive to the polymer electrolyte solution obtained in step 3, and stir to mix evenly to obtain a two-dimensional material additive solvent;

[0021] Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, stir at room temperature for 6 hours, and obtain a lithium solid-state battery electrolyte solution.

[0022] Furthermore, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) with a molecular weight of 287.08, lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), and lithium bis(oxalatoborate) (LiBOB); the solid-state battery polymer material is one or more of polyvinylidene fluoride-hexafluoropropylene PVDF-HFP with a molecular weight of 400,000, PEO, PVC, PEG, PVA, PVDF, PAN-PVA, and PAN-PEG; and the aprotic polar solvent is N,N-dimethylformamide or N-methylpyrrolidone (NMP).

[0023] Furthermore, the electrolyte solution includes 34 wt % of lithium salt, 61 wt % of solid-state battery polymer material, and 5 wt % of two-dimensional material additive.

[0024] Furthermore, in step 4, the stirring time is 3-6 hours and the temperature is 20-40°C.

[0025] The beneficial effects of the present invention compared to the prior art are:

[0026] 1. The present invention proposes a lithium solid-state battery electrolyte, which effectively improves the mechanical properties and ionic conductivity of the electrolyte by adding two-dimensional material additives to commercial solid-state electrolyte.

[0027] 2. The integrated structure of the lithium solid-state battery electrolyte, negative electrode and current collector prepared by the present invention can effectively improve the poor rate performance of traditional graphite negative electrode materials. Its strong and stable lithium ion transmission path and interface performance enable high-rate lithium solid-state batteries to be realized.

[0028] 3. The present invention proposes a method for preparing a lithium solid-state battery electrolyte, which has a simple process, is easy to implement, and can be directly matched with emerging improvement schemes between electrodes.

[0029] 4. This invention proposes an integrated structure of a lithium-solid-state battery electrolyte, anode, and current collector, which effectively improves the electrolyte's lithium-ion transport capacity, enhances mechanical and interfacial properties, and suppresses the growth of lithium dendrites. A CR2032 lithium-solid-state battery (a lithium half-cell with a two-dimensional material as the negative electrode active material) fabricated based on this invention can achieve a capacity of 206.64 mAh / g at a 5C rate and only decays by 24% after 1500 charge and discharge cycles, compared to a commercial graphite anode capacity decay of up to 60%. This demonstrates that lithium-solid-state batteries fabricated based on this invention can meet the high capacity, high rate, long life, and low decay requirements of electronic devices.

[0030] 5. The proposed lithium-solid-state battery 2D material anode and electrolyte structure containing 2D material additives effectively improve the electrolyte's ionic conductivity, ultimately significantly increasing the battery's cycle capacity. Compared to commercial graphite anodes, the discharge specific capacity is increased by 160%.

[0031] 6. The present invention proposes a method for preparing an integrated lithium solid-state battery electrolyte, negative electrode and current collector. The process is simple, easy to implement, and can be directly matched with other emerging improvement solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 TG curves of the homemade electrolyte containing 5% by weight of the two-dimensional material additive and a commercial electrolyte (i.e., the two-dimensional material content is 0 wt%) in Example 1 of the present invention (the ordinate indicates the percentage of weight lost during the heating process to the total weight of the sample);

[0033] Figure 2 TGA curves of the homemade electrolyte containing 5% by weight of the two-dimensional material additive and the commercial electrolyte (i.e., the two-dimensional material content is 0 wt%) in Example 1 of the present invention (the ordinate refers to the rate at which the sample loses weight during the heating process);

[0034] Figure 3This is a graph showing the lithium ion migration number test results of a homemade electrolyte containing 5% by weight of the two-dimensional material additive in Example 1 of the present invention.

[0035] Figure 4 Graph showing the lithium ion migration number test results of the commercial electrolyte (i.e., the content of the two-dimensional material is 0 wt%) in Example 1 of the present invention.

[0036] Figure 5 This is a tensile test performance diagram of the homemade electrolyte and the commercial electrolyte with a two-dimensional material additive content of 5 wt% in Example 1 of the present invention.

[0037] Figure 6 Graphs showing cycle testing at 5C rate for lithium half-cells in Example 1 of the present invention using a homemade electrolyte and a commercial electrolyte containing 5 wt% of a two-dimensional material additive, respectively.

[0038] Figure 7 These are rate test graphs for lithium half-cells using a homemade electrolyte and a commercial electrolyte with a two-dimensional material additive content of 5 wt% in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0040] By incorporating two-dimensional materials into solid-state battery polymer materials, this invention produces a solid electrolyte with excellent mechanical properties and high ionic conductivity. This effectively improves the interfacial properties between the positive and negative electrodes, effectively inhibiting the growth of lithium dendrites. It also forms a unique ion pathway with the positive and negative electrodes, improving ion transmission efficiency.

[0041] By using two-dimensional materials as the negative electrode active material, the present invention improves cycle stability and theoretical specific capacity due to the isotropy and high ion attachment sites of two-dimensional materials. Furthermore, the dense SEI film formed during the activation process effectively inhibits the growth of lithium dendrites, significantly improving the battery's rate performance.

[0042] The present invention dehydrates the two-dimensional material ink to form a film with a density of 4.5g / cm 2 The conductivity of the two-dimensional material film is only half of that of copper, while the difference is not much. Therefore, using the two-dimensional material film as the negative electrode current collector can greatly improve the energy density of the battery.

[0043] The present invention adds two-dimensional materials to the negative electrode, current collector and electrolyte at the same time, which has the following advantages: (1) It can form a unique lithium ion transmission path, not only because the conductivity of the two-dimensional material is higher than that of the polymer-based electrolyte, but also because the three are closely connected and the interface contact is seamless, which greatly improves the performance of lithium ion transmission; (2) The two-dimensional material used as the negative electrode active material greatly improves the discharge specific capacity (such as Figure 4 As shown in the figure, the discharge current of the two-dimensional material is larger than that of the graphite negative electrode at the same rate, and lithium dendrites are more likely to form. Therefore, a strong electrolyte is needed as a support. The high mechanical strength of the two-dimensional material makes it difficult for lithium dendrites to penetrate, thereby improving the high-rate performance of the solid-state battery. (3) The two-dimensional material as a current collector can actually make up for the lack of two-dimensional material as a negative electrode active material. At the same time, it can be regarded as a negative electrode (the current collector is the negative electrode), so it can effectively improve the energy density of the battery. As mentioned above, the combination of the three is indispensable and is a necessary structure for realizing high-rate lithium solid-state batteries.

[0044] In the present invention, the electrolyte is mainly based on commercial solid-state battery polymer materials (including but not limited to PEO, PVC, PEG, PVA, PVDF, PVDF-HFP, PAN-PVA, PAN-PEG, etc.), to which two-dimensional materials are added (including but not limited to MXene (Ti3C2), graphene, silicene, germanene, molybdenum disulfide (MoS2), two-dimensional graphite carbon nitride (g-C3N4), layered double hydroxides (LDHs), boron nitride (BN), covalent organic frameworks (COFs), titanium nitride (Ti2N), etc.); the negative electrode and current collector are mainly based on the above-mentioned two-dimensional materials, and the three are integrated into one, which effectively improves the ionic conductivity, mechanical strength and lithium ion transfer number of the electrolyte.

[0045] In the present invention, the additive is a two-dimensional material with excellent physical and chemical properties. Due to its good lithium affinity and conductivity, the high-rate long-cycle performance of the battery is significantly improved. At the same time, its strong mechanical properties inhibit the growth of lithium dendrites and improve the cycle stability of the battery. The commercial solid-state battery polymer material is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). Its good film-forming properties make it an excellent material for preparing electrolyte membranes. Compared with traditional polymer electrolytes, it can reduce the crystallinity of PVDF and weaken the reaction activity of -F, which is conducive to absorbing more electrolyte and improving the interface stability between the electrode and the electrolyte. The commercial lithium salt is lithium bis(trifluoromethanesulfonyl imide), which has high electrochemical stability and conductivity, and has no corrosive effect on the aluminum current collector at higher voltages, thereby effectively improving the cycle performance of the battery.

[0046] Example 1:

[0047] A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, wherein the specific steps of preparing the anode are:

[0048] Step 1: Add Ti3C2 as the negative electrode active material, a commercial binder, and a commercial conductive agent in a mass ratio of 6:3:1 to 2.5 ml of N-methylpyrrolidone (NMP), with a total solute amount of 0.5-1.5 g, and stir at room temperature for more than 24 hours to obtain a Ti3C2 negative electrode solution;

[0049] Step 2: Apply the Ti3C2 negative electrode solution to a thickness of 200 μm on the Ti3C2 negative electrode current collector, and dry it in a vacuum oven at 80°C for 12 h to obtain the Ti3C2 negative electrode for the lithium solid-state battery.

[0050] This embodiment also provides a lithium solid-state battery electrolyte, including 34 wt% of a commercial lithium salt, 61 wt% of a commercial solid-state battery polymer material, and 5 wt% of a two-dimensional material additive, wherein the commercial lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the commercial solid-state battery polymer material is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and the two-dimensional material additive is Ti3C2.

[0051] The above-mentioned method for preparing the lithium solid-state battery electrolyte, negative electrode and current collector comprises the following steps:

[0052] Step 1: Dry the commercial lithium salt in a vacuum oven for one week at a temperature of 50-80°C.

[0053] Step 2: Place the dried lithium salt obtained in step 1 into a glove box, wherein the water and oxygen values ​​in the glove box are less than 0.01 ppm.

[0054] Step 3: In a glove box, dissolve the commercial solid-state battery polymer material in 4 g of commercial aprotic polar solvent N,N-dimethylformamide (DMF) and stir at room temperature for 6 h to obtain a commercial polymer electrolyte solution.

[0055] Step 4: In a glove box, add the two-dimensional material additive to the commercial polymer electrolyte solution obtained in step 3, stir and mix evenly, and obtain a two-dimensional material additive solvent; wherein the mass percentage of the commercial solid-state battery polymer material in step 3 is 61wt%, and the mass percentage of the two-dimensional material additive is 5wt%;

[0056] Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, and stir at room temperature for 6 hours to obtain a lithium solid-state battery electrolyte solution; wherein the mass percentage of lithium salt is 34wt%;

[0057] Step 6: In a glove box, apply the lithium solid-state battery electrolyte solution to a thickness of 200 μm on the Ti3C2 negative electrode of the lithium solid-state battery, and dry it in a vacuum oven at 80°C for 12 hours to obtain a lithium solid-state battery electrolyte, negative electrode and current collector.

[0058] Figure 1 and Figure 2 The weight change and weight change rate of the electrolyte during temperature increase are shown, respectively. It can be seen that the temperature at which the weight changes primarily increases from approximately 305°C to 320°C after the addition of the two-dimensional material. These test results indicate that the addition of the two-dimensional material additive significantly improves the thermal stability and ignition point of the electrolyte, contributing to improved battery safety and stability.

[0059] Figure 3 and Figure 4 The comparison results show that the lithium ion migration number of the homemade electrolyte is higher than that of the commercial electrolyte, and the impedance of the battery before and after polarization is also lower than that of the commercial electrolyte. From the test results, it can be concluded that the electrolyte with the addition of two-dimensional material additives has improved the ionic conductivity and lithium ion mobility, which is beneficial to improving the ionic conductivity and cycle capacity of the battery. Figure 3 and Figure 4 This compares the lithium-ion transference number (LIM). A high LIM primarily indicates more efficient lithium-ion transfer within the battery, significantly improving the battery's fast-charging capability, energy density, and power density while reducing polarization during charge and discharge. This metric reflects the contribution of lithium ions to the total ionic conductivity of the electrolyte. A higher value (approaching 1) indicates a more optimized charge transfer efficiency.

[0060] The two electrolytes were cut into 10×10×60 mm strips and subjected to tensile tests. Figure 5 From the figure, it can be observed that the strain of the homemade electrolyte with 5wt% two-dimensional material exceeds 200%, while the strain of the commercial electrolyte is only 90%, indicating that the introduction of two-dimensional material additives can significantly improve the mechanical properties of the electrolyte.

[0061] Figure 5 The stress-strain curve obtained from a tensile test reflects the stiffness of the electrolyte: the greater the slope of the line in the elastic phase, the higher the material's stiffness; strength: the tensile strength (the highest point of the curve) and yield strength determine the material's load-bearing capacity; and plasticity: the total strain value or elongation corresponding to the breaking point reflects the material's ability to deform; the larger the value, the better the plasticity. It can be seen that the homemade electrolyte's stiffness, strength, and plasticity are all superior to commercial electrolytes.

[0062] Figure 6 This is a graph of cycle number-discharge specific capacity under 5C (high rate), which proves that the integrated structure has high discharge specific capacity and stable cycle. Figure 7It reflects the discharge specific capacity of the battery at different rates, and the results show that the integrated structure has better rate performance.

[0063] Example 2:

[0064] A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, wherein the specific steps of preparing the anode are:

[0065] Step 1: Add graphene as the negative electrode active material, a commercial binder, and a commercial conductive agent in a mass ratio of 6:3:1 to 2.5 ml of N-methylpyrrolidone (NMP), with a total solute amount of 0.5-1.5 g, and stir at room temperature for more than 24 hours to obtain a graphene negative electrode solution;

[0066] Step 2: Apply the graphene negative electrode solution to a thickness of 200 μm on the Ti3C2 negative electrode current collector, and dry it in a vacuum oven at 80°C for 12 h to obtain a lithium solid-state battery graphene negative electrode.

[0067] This embodiment provides a lithium solid-state battery electrolyte, including 34 wt% of a commercial lithium salt, 61 wt% of a commercial solid-state battery polymer material, and 5 wt% of a two-dimensional material additive, wherein the commercial lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the commercial solid-state battery polymer material is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and the two-dimensional material additive is graphene.

[0068] The present invention also provides a method for preparing the above-mentioned lithium solid-state battery electrolyte, which specifically comprises the following steps:

[0069] Step 1: Dry the commercial lithium salt in a vacuum oven for one week at a temperature of 50-80°C.

[0070] Step 2: Place the dried lithium salt obtained in step 1 into a glove box, wherein the water and oxygen values ​​in the glove box are less than 0.01 ppm.

[0071] Step 3: In a glove box, dissolve the commercial solid-state battery polymer material in 4 g of commercial aprotic polar solvent N,N-dimethylformamide (DMF) and stir at room temperature for 6 h to obtain a commercial polymer electrolyte solution.

[0072] Step 4: In a glove box, add the two-dimensional material additive to the commercial polymer electrolyte solution obtained in step 3, stir and mix evenly, and obtain a two-dimensional material additive solvent; wherein the mass percentage of the commercial solid-state battery polymer material in step 3 is 61wt%, and the mass percentage of the two-dimensional material additive is 5wt%;

[0073] Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, and stir at room temperature for 6 hours to obtain a lithium solid-state battery electrolyte solution; wherein the mass percentage of lithium salt is 34wt%;

[0074] Step 6: In a glove box, apply the lithium solid-state battery electrolyte solution to a thickness of 200 μm on the lithium solid-state battery graphene negative electrode, and dry it in a vacuum oven at 80° C. for 12 hours to obtain the lithium solid-state battery electrolyte, negative electrode and current collector.

[0075] Example 3:

[0076] A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, wherein the specific steps of preparing the anode are:

[0077] Step 1: Add silicene as the negative electrode active material, a commercial binder, and a commercial conductive agent in a mass ratio of 6:3:1 to 2.5 ml of N-methylpyrrolidone (NMP), with a total solute amount of 0.5-1.5 g, and stir at room temperature for more than 24 hours to obtain a silicene negative electrode solution;

[0078] Step 2: Apply the silicene negative electrode solution to a thickness of 200 μm on the Ti3C2 negative electrode current collector, and dry it in a vacuum oven at 80°C for 12 h to obtain a lithium solid-state battery silicene negative electrode.

[0079] This embodiment provides a lithium solid-state battery electrolyte, including 34 wt% of a commercial lithium salt, 61 wt% of a commercial solid-state battery polymer material, and 5 wt% of a two-dimensional material additive, wherein the commercial lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the commercial solid-state battery polymer material is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and the two-dimensional material additive is silicene.

[0080] The present invention also provides a method for preparing the above-mentioned lithium solid-state battery electrolyte, which specifically comprises the following steps:

[0081] Step 1: Dry the commercial lithium salt in a vacuum oven for one week at a temperature of 50-80°C.

[0082] Step 2: Place the dried lithium salt obtained in step 1 into a glove box, wherein the water and oxygen values ​​in the glove box are less than 0.01 ppm.

[0083] Step 3: In a glove box, a commercial solid-state battery polymer material was dissolved in 4 g of a commercial aprotic polar solvent N,N-dimethylformamide (DMF), and stirred at room temperature for 6 h to obtain a commercial polymer electrolyte solution.

[0084] Step 4: In a glove box, add the two-dimensional material additive to the commercial polymer electrolyte solution obtained in step 3, stir and mix evenly, and obtain a two-dimensional material additive solvent; wherein the mass percentage of the commercial solid-state battery polymer material in step 3 is 61wt%, and the mass percentage of the two-dimensional material additive is 5wt%;

[0085] Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, and stir at room temperature for 6 hours to obtain a lithium solid-state battery electrolyte solution; wherein the mass percentage of lithium salt is 34wt%;

[0086] Step 6: In a glove box, apply the lithium solid-state battery electrolyte solution to a thickness of 200 μm on the lithium solid-state battery silicene negative electrode, and dry it in a vacuum oven at 80° C. for 12 h to obtain a lithium solid-state battery electrolyte, negative electrode and current collector.

[0087] Example 4:

[0088] A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, wherein the specific steps of preparing the anode are:

[0089] Step 1: Add germanium ene as the negative electrode active material, a commercial binder, and a commercial conductive agent in a mass ratio of 6:3:1 to 2.5 ml of N-methylpyrrolidone (NMP), with a total solute amount of 0.5-1.5 g, and stir at room temperature for more than 24 hours to obtain a germanium ene negative electrode solution;

[0090] Step 2: Apply the germanium ene negative electrode solution on the Ti3C2 negative electrode current collector with a thickness of 200 μm, and dry it in a vacuum oven at 80° C. for 12 h to obtain the lithium solid-state battery germanium ene negative electrode.

[0091] This embodiment provides a lithium solid-state battery electrolyte, including 34 wt% of a commercial lithium salt, 56 wt% of a commercial solid-state battery polymer material, and 10 wt% of a two-dimensional material additive, wherein the commercial lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the commercial solid-state battery polymer material is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and the two-dimensional material additive is germanene.

[0092] The present invention also provides a method for preparing the above-mentioned lithium solid-state battery electrolyte, which specifically comprises the following steps:

[0093] Step 1: Dry the commercial lithium salt in a vacuum oven for one week at a temperature of 50-80°C.

[0094] Step 2: Place the dried lithium salt obtained in step 1 into a glove box, wherein the water and oxygen values ​​in the glove box are less than 0.01 ppm.

[0095] Step 3: In a glove box, dissolve the commercial solid-state battery polymer material in 4 g of commercial aprotic polar solvent N,N-dimethylformamide (DMF) and stir at room temperature for 6 h to obtain a commercial polymer electrolyte solution.

[0096] Step 4: In a glove box, add the two-dimensional material additive to the commercial polymer electrolyte solution obtained in step 3, stir and mix evenly, and obtain a two-dimensional material additive solvent; wherein the mass percentage of the commercial solid-state battery polymer material in step 3 is 61wt%, and the mass percentage of the two-dimensional material additive is 5wt%;

[0097] Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, and stir at room temperature for 6 hours to obtain a lithium solid-state battery electrolyte solution; wherein the mass percentage of lithium salt is 34wt%;

[0098] Step 6: In a glove box, apply the lithium solid-state battery electrolyte solution to a thickness of 200 μm on the lithium solid-state battery germanium ene negative electrode, and dry it in a vacuum oven at 80° C. for 12 hours to obtain the lithium solid-state battery electrolyte, negative electrode and current collector.

[0099] Comparison of Examples:

[0100] Example Commercial electrolytes Example 1 Example 2 Example 3 Example 4 strain 90％ 210％ 185％ 205％ 165％ Lithium ion migration number 0.22 0.35 0.33 0.30 0.31 Ionic conductivity 1.03mS / cm 13.8mS / cm 12.5mS / cm 11.6mS / cm 8.9mS / cm Discharge capacity (0.5C) 186 mAh / g 308 mAh / g 297 mAh / g 304 mAh / g 287 mAh / g Discharge capacity (5C) 85 mAh / g 218 mAh / g 224 mAh / g 207 mAh / g 216 mAh / g Flash Point 305 ℃ 320 ℃ 334 ℃ 315 ℃ 335 ℃

Claims

1. A method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector, characterized by: The method comprises: coating a lithium solid-state battery electrolyte solution on a negative electrode with a thickness of 100-500 μm, and vacuum drying the solution at 80° C. in a vacuum oven for 12 hours to obtain an integrated structure of a lithium solid-state battery electrolyte, a negative electrode, and a current collector; the electrolyte solution, the negative electrode, and the current collector all contain two-dimensional materials.

2. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 1, characterized in that: The two-dimensional material is one or more of MXene (Ti3C2), graphene, silicene, germanene, molybdenum disulfide (MoS2), two-dimensional graphitic carbon nitride (g-C3N4), layered double hydroxides (LDHs), boron nitride (BN), covalent organic frameworks (COFs) or titanium nitride (Ti2N).

3. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 1 or 2, characterized in that: The specific steps of preparing the negative electrode are: Step 1: Add the two-dimensional material as the negative electrode active material, a binder, and a conductive agent in a mass ratio of 6:3:1 into N-methylpyrrolidone (NMP), and stir at room temperature for more than 24 hours to obtain a two-dimensional material negative electrode solution; Step 2: Apply the two-dimensional material negative electrode solution on the two-dimensional material negative electrode current collector, and dry it in a vacuum oven at 80° C. for 12 hours to obtain the lithium solid-state battery negative electrode.

4. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 3, characterized in that: In step 1, the adhesive is polyvinylidene fluoride; and the conductive agent is conductive carbon black (SuperP).

5. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 3, characterized in that: In step 2, the two-dimensional material negative electrode current collector is a 95 vol% two-dimensional material aqueous dispersion that is centrifuged, and the bottom large sheet of two-dimensional material is coated on a glass plate with a thickness of 500 nm to obtain a two-dimensional material negative electrode current collector.

6. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 1 or 2, characterized in that: The preparation method of the electrolyte solution comprises the following steps: Step 1: Dry the lithium salt in a vacuum oven for one week, wherein the vacuum oven temperature is set to 50-80°C; Step 2: placing the dried lithium salt obtained in step 1 into a glove box; wherein the water and oxygen values ​​in the glove box are all less than 0.01 ppm; Step 3: In a glove box, dissolve the solid-state battery polymer material in an aprotic polar solvent and stir at room temperature for 6 hours to obtain a polymer electrolyte solution; Step 4: In a glove box, add the two-dimensional material additive to the polymer electrolyte solution obtained in step 3, and stir to mix evenly to obtain a two-dimensional material additive solvent; Step 5: In a glove box, add lithium salt to the two-dimensional material added solvent obtained in step 4, stir at room temperature for 6 hours, and obtain a lithium solid-state battery electrolyte solution.

7. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 6, characterized in that: The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), and lithium bis(oxalatoborate) (LiBOB); the solid-state battery polymer material is one or more of PVDF-HFP, PEO, PVC, PEG, PVA, PVDF, PAN-PVA, and PAN-PEG; and the aprotic polar solvent is N,N-dimethylformamide or N-methylpyrrolidone (NMP).

8. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 6, characterized in that: The electrolyte solution includes 34 wt% of lithium salt, 61 wt% of solid-state battery polymer material, and 5 wt% of two-dimensional material additive.

9. The method for preparing an integrated structure of a lithium solid-state battery electrolyte, anode and current collector according to claim 6, characterized in that: In step 4, the stirring time is 3-6 hours and the temperature is 20-40°C.

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