Solid electrolyte, solid lithium ion battery and preparation method of solid electrolyte and solid lithium ion battery

Abstract

The invention belongs to the field of solid-state batteries, and particularly relates to a solid-state electrolyte with a wide electrochemical window and a solid-state lithium ion battery. According to the solid electrolyte, the metal oxyhalide and the lithium-containing zeolite are subjected to ball milling, so that the solid electrolyte with relatively high ionic conductivity and a wide electrochemical window is obtained. The solid-state electrolyte is prepared into a solid-state electrolyte membrane, the solid-state electrolyte membrane, a positive electrode and a negative electrode are assembled into a solid-state lithium battery, an ionic liquid electrolyte and a polymer monomer are added, and the solid-state lithium battery is obtained through in-situ polymerization. A polymer network exists in the solid-state lithium battery, so that the lithium ion transmission performance in the positive electrode, the negative electrode and the solid-state electrolyte and the interface transmission performance of lithium ions in the positive electrode, the negative electrode and the solid-state electrolyte can be effectively improved, and the solid-state lithium battery has higher discharge capacity and better cycling stability performance.

Description

Technical Field

[0001] The present invention belongs to the field of solid-state batteries, and particularly relates to a solid electrolyte with a wide electrochemical window and a solid-state lithium-ion battery. Background Art

[0002] With the advancement of the country's "dual carbon" goal, the popularity of electric vehicles has increased rapidly, and the demand for power batteries has increased sharply. At the same time, with the development of the low-altitude economy, the demand for power batteries for drones and the like has also increased rapidly. The transportation field has high requirements for the energy density of power batteries, but high energy density means high safety hazards. Therefore, it is an inevitable trend to develop high-safety solid-state batteries to replace traditional liquid batteries. Currently, solid electrolytes represented by sulfides have the prospect of industrialization due to their high lithium-ion conductivity. However, such solid electrolytes have disadvantages such as poor air stability, high cost, and narrow electrochemical windows. Moreover, such solid electrolytes also have poor elasticity and require a large pressure to be applied during use, and their industrialization still faces great challenges. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a solid electrolyte with a wide electrochemical window.

[0004] Another purpose of the present invention is to provide a solid-state lithium battery with a wide electrochemical window.

[0005] In order to achieve the above purposes, the present invention is implemented by adopting the following technical solutions:

[0006] A solid electrolyte, characterized in that it is obtained by ball-milling and mixing a lithium-containing zeolite and a metal halogen oxide; the lithium-containing zeolite is obtained by subjecting a sodium-containing zeolite to lithium ion exchange and performing vacuum dehydration treatment;

[0007] The molar ratio of lithium to metal halogen oxide in the lithium-containing zeolite is 1 to 3:1;

[0008] The chemical formula of the lithium-containing zeolite is Li2Al2Si 2+x O 8+2x , where 0 ≤ x ≤ 3;

[0009] The metal in the metal halogen oxide is selected from at least one of Bi, Al, Fe, V, In, Cr, Sc, La, and Sm;

[0010] The rotation speed of the ball milling is not less than 400 rpm.

[0011] Experiments have shown that after ball-milling and compounding metal haloxides and lithium-containing zeolites at a speed of not less than 400 rpm, the lithium-ion conductivity of lithium-containing zeolites can be significantly improved. At the same time, vacuum dehydration treatment is also carried out during the preparation process of lithium-containing zeolites to increase the lithium-ion conductivity in lithium-containing zeolites. In addition, the solid electrolyte has the characteristic of a wide electrochemical window, and its electrochemical window is wider than 0.05 - 4.6 V, and can even reach up to 4.8 V, far higher than that of general solid electrolytes which are only in the range of 0.1 - 4.5 V. At the same time, the lithium-ion conductivity of the solid electrolyte is above 1.0×10 -4 S / cm.

[0012] Preferably, the rotation speed of the ball-milling is 400 - 600 rpm, and the ball-milling time is 8 - 25 hours. Experiments have found that under these conditions, the obtained solid electrolyte has better ion conductivity.

[0013] More preferably, the ball-milling time is preferably 10 - 20 hours.

[0014] Preferably, the temperature of the vacuum dehydration treatment is 300 - 500 °C.

[0015] Preferably, the time of the vacuum dehydration is 1 - 10 hours.

[0016] Preferably, the lithium-containing zeolite is a lithium aluminosilicate-type zeolite, and its chemical formula is Li2Al2Si 2+x O 8+2x , where 0 ≤ x ≤ 3.

[0017] More specifically, the lithium-containing zeolite can be prepared by the following method: Select a sodium-containing zeolite, such as Na2Al2Si 2+x O 8+2x , where 0 ≤ x ≤ 3. Then soak it in a lithium-ion exchanger solution. The lithium-ion exchanger can be a water-soluble lithium salt, and the specific types can be LiCl, LiNO3 or Li2SO4, etc. In the lithium-ion exchanger solution, the concentration of lithium ions is 1 - 10 mol / L.

[0018] Preferably, the temperature during the soaking is 20 - 80 °C. Preferably, the soaking time is 1 - 10 hours.

[0019] Preferably, the average particle size of the lithium-containing zeolite is 100 - 500 nanometers, and the specific surface area is 300 - 800 m 2 / g.

[0020] The metal haloxide is a well-known substance in the art, and its structure can be abbreviated as AOB, where A represents a metal and B represents a halogen element. The metal haloxide can be prepared by a solid-phase method or a liquid-phase method.

[0021] Taking BiOCl as an example, it is prepared by a hydrothermal reaction of Bi(NO3)3 and KCl solution at 140 - 200 °C for 5 - 20 hours. Taking FeOCl as an example, it can be prepared by calcining FeCl3·6H2O in air at 210 - 250 °C for 1 - 5 hours.

[0022] A solid-state lithium-ion battery includes a silicon-based negative electrode, the solid electrolyte, a positive electrode, and a polymer network and an ionic liquid electrolyte distributed throughout the battery.

[0023] Preferably, the polymer network is formed from acrylate monomers.

[0024] Preferably, the acrylate monomer is an acrylate monomer with 8 or fewer carbon atoms, more preferably an acrylate monomer with 6 or fewer carbon atoms. Specifically, it can be ethyl acrylate, methyl methacrylate, methyl acrylate, methyl methoxyacrylate, or ethyl methoxyacrylate, etc.

[0025] After polymerization, acrylate monomers with fewer carbon atoms are more likely to form hydrogen bond interactions with N, S, and F ions in bis(trifluoromethanesulfonyl)imide anions.

[0026] Preferably, the silicon-based negative electrode is selected from elemental silicon, silicon monoxide, lithium-silicon alloy, or silicon-carbon composite.

[0027] More specifically, the lithium-silicon alloy is selected from LiSi, Li 12 Si7, Li7Si3, Li 13 Si4, Li 15 Si4 or Li 22 Si5.

[0028] More specifically, the silicon in the silicon-carbon composite is selected from elemental silicon, silicon monoxide, or lithium-silicon alloy, and the silicon content in the silicon-carbon composite is 5 - 50 wt%.

[0029] Preferably, the ionic liquid electrolyte includes an ionic liquid and a lithium salt.

[0030] Preferably, the anion of the ionic liquid is selected from bis(trifluoromethanesulfonyl)imide anion; the cation of the ionic liquid is selected from one or more of pyrrole-based, piperidine-based, or imidazole-based cations.

[0031] Preferably, the lithium salt can be one or more of LiPF6, LiClO4, LiBF4, LiTFSI, LiFSI, LiBOB, or LiDFOB. More preferably, the lithium salt is more preferably LiTFSI.

[0032] The N, S, and F ions in the bis(trifluoromethanesulfonyl)imide anion in the ionic liquid and lithium salt can form hydrogen bond interactions with the hydrogen atoms in the methyl or methylene groups of the polyacrylate to form a polymer network. The formation of this polymer network can promote the dissociation of the lithium salt, thereby increasing the lithium ion conductivity and lithium ion transference number of the polymer network. Since the polymer network is formed in the last step of preparing the solid-state lithium ion battery, the polymer network will be dispersed throughout the battery, including in the pores of the positive electrode, silicon-based negative electrode, and solid electrolyte, as well as at the interfaces between the solid electrolyte and the positive and negative electrodes, thereby improving the lithium ion transport performance in the positive and negative electrodes and the lithium ion transport performance at the interfaces between the positive and negative electrodes and the solid electrolyte.

[0033] Preferably, the concentration of the lithium salt in the ionic liquid electrolyte is 1 to 3 mol / L.

[0034] The preparation method of the solid-state lithium ion battery includes the following steps:

[0035] Prepare the negative electrode film;

[0036] Prepare the solid electrolyte and make it into a solid electrolyte film;

[0037] Prepare the positive electrode film;

[0038] Stack, encapsulate the negative electrode film, solid electrolyte film, and positive electrode film, and then inject the ionic liquid electrolyte, the polymer monomer for forming the polymer network, and the initiator, and obtain the solid-state lithium ion battery through in-situ polymerization reaction.

[0039] In this application, the binder used for preparing the negative electrode film, solid electrolyte film, and positive electrode film is preferably a fluoropolymer binder. More specifically, the binder is polytetrafluoroethylene. Polytetrafluoroethylene can be shear fibrillated, which is beneficial for film formation and bonding.

[0040] More specifically, the negative electrode film includes a silicon-based negative electrode material, a binder, and a conductive agent. More preferably, the weight ratio of the silicon-based negative electrode material, binder, and conductive agent is 90 to 96:0.1 to 5:1 to 5.

[0041] Preferably, the thickness of the negative electrode film is 10 to 100 μm. Under this condition, the cycle life and energy density of the battery can be taken into account.

[0042] Preferably, in the solid electrolyte film, the weight ratio of the solid electrolyte to the fluoropolymer is 0.1 to 5:100.

[0043] Preferably, the thickness of the solid electrolyte film is 10 to 100 μm. Under this condition, the cycle life and energy density of the battery can be taken into account.

[0044] Preferably, the positive electrode film comprises a positive electrode material, a binder, a conductive agent, and the above-mentioned solid electrolyte. More preferably, the weight ratio of the positive electrode material, the binder, the conductive agent, and the solid electrolyte is 80-95:0.1-5:1-5:1-10.

[0045] Preferably, the conductive agent of the positive electrode film and the negative electrode film can be a commonly used conductive agent in the art. Common examples are graphene, acetylene black, Super P, carbon nanotubes, and carbon nanofibers.

[0046] Preferably, the positive electrode material can be a commonly used material in the art. For example, commercial spinel lithium manganate, spinel nickel manganese lithium, lithium manganese phosphate, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt phosphate, lithium vanadium phosphate, lithium cobalt oxide, nickel cobalt aluminum-based layered material, nickel cobalt manganese-based layered material, or lithium-rich manganese-based layered material.

[0047] Preferably, the weight ratio of the ionic liquid electrolyte to the acrylate monomer is 2-4:1.

[0048] Preferably, the total weight ratio of the ionic liquid electrolyte and the acrylate monomer to the solid electrolyte weight is 0.1-0.5:1.

[0049] The addition amount of the initiator can refer to the prior art.

[0050] Preferably, the temperature of the in-situ polymerization reaction is 50-80 °C.

[0051] Preferably, the time of the in-situ polymerization reaction is 30-120 minutes.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention discloses a solid electrolyte. By ball-milling a metal halide oxide with a lithium-containing zeolite, a solid electrolyte with a wide electrochemical window is obtained. At the same time, the solid electrolyte has a low cost and excellent air stability, that is, when the zeolite-based solid electrolyte is exposed to air, no alkaline substances will form on the surface. A solid electrolyte film is made from the solid electrolyte, assembled with a positive electrode and a negative electrode into a solid-state lithium battery, and an ionic liquid electrolyte and a polymer monomer are added. A solid-state lithium battery is obtained by in-situ polymerization. There is a polymer network in the solid-state lithium battery, which can effectively improve the lithium ion transportability in the positive and negative electrodes and the solid electrolyte, and the interfacial transportability of lithium ions between the positive and negative electrodes and the solid electrolyte. And the solid-state lithium battery has a higher discharge capacity and better cycle stability. Description of the Drawings

[0054] Figure 1 TEM photograph of the solid electrolyte with a wide electrochemical window prepared in Example 1;

[0055] Figure 2 The impedance spectrum of the wide electrochemical window solid electrolyte prepared in Example 1;

[0056] Figure 3 The charge and discharge curve of the solid-state lithium-ion battery prepared in Example 1;

[0057] Figure 4 This is a cycle life diagram of the solid-state lithium-ion battery prepared in Example 1;

[0058] Figure 5 This is a cycle life diagram of the solid-state lithium-ion battery prepared in Comparative Example 1. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with specific examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0060] Example 1

[0061] Preparation of solid electrolyte:

[0062] Aladdin reagent Na2Al2Si 2.5 O9·nH2O zeolite (commercially available) was ion exchanged in a 5 mol / L LiCl aqueous solution. The average particle size of the zeolite was 400 nm and the specific surface area was 650 m 2 / g, the ion exchange temperature was 60°C, the ion exchange time was 4 hours, and then 400 ℃ Vacuum dehydration to obtain Li2Al2Si 2.5 O9.

[0063] Li2Al2Si 2.5 O9 and FeOCl are compounded by ball milling to obtain zeolite solid electrolyte, in which Li2Al2Si 2.5 The molar ratio of O9 to FeOCl is 1:1, the ball milling speed is 500 rpm, and the ball milling time is 10 hours. The microstructure of the solid electrolyte is shown in Figure 1 The ionic conductivity was 1.2×10 -4 S / cm, see Figure 2 The electrochemical window of the solid electrolyte was measured to be 0.05-4.7 V by linear sweep voltammetry (scan rate 0.1 mV / s).

[0064] Preparation of solid-state lithium-ion batteries:

[0065] S1 Preparation of the negative electrode film:

[0066] Mix silicon carbide containing 8 wt% silicon, polytetrafluoroethylene, and acetylene black in a weight ratio of 95:1.5:3.5, and obtain the negative electrode film through shear dispersion and roll pressing. The thickness of the negative electrode film is 50 microns.

[0067] S2 Preparation of the solid electrolyte film:

[0068] Mix the above solid electrolyte with polytetrafluoroethylene and prepare the solid electrolyte film using the dry method; wherein, the weight ratio of the solid electrolyte to polytetrafluoroethylene is 100:1.

[0069] S3 Preparation of the positive electrode film:

[0070] Mix LiNi 0.83 Co 0.10 Mn 0.07 O2 cathode material, polytetrafluoroethylene, Super P, and the above solid electrolyte by dry mixing in a weight ratio of 90:1:4:5, and obtain the positive electrode film through shear dispersion and roll pressing.

[0071] S4 Preparation of the solid-state lithium-ion battery:

[0072] Stack and encapsulate the negative electrode film, the solid electrolyte film, and the positive electrode film, then inject an ionic liquid electrolyte, ethyl acrylate monomer, and azobisisobutyronitrile initiator, and perform an in-situ polymerization reaction at 60°C for 60 minutes to obtain the solid-state lithium-ion battery.

[0073] In the ionic liquid electrolyte, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, the lithium salt is LiTFSI, and the concentration of the lithium salt in the ionic liquid electrolyte is 1 mol / L.

[0074] The weight ratio of the ionic liquid electrolyte to the ethyl acrylate monomer is 3:1, the total weight of the ionic liquid electrolyte and the ethyl acrylate monomer to the weight of the solid electrolyte is 0.3:1, and the weight ratio of the initiator to the ethyl acrylate monomer is 1:100. The relationship between the usage amount of the ionic liquid and the battery capacity is that the usage amount of the ionic liquid per Ah of battery capacity is 1 gram.

[0075] Perform constant current-constant voltage charge and discharge at room temperature on the solid-state lithium-ion battery prepared in Example 1 within the voltage range of 2.5 to 4.25V. The charge and discharge process is as follows: first, charge at a constant current of 0.5C to 4.25V and then at a constant voltage until the current is lower than 0.02C (1C is defined as 200 mA / g), and then discharge at a current of 0.2C to 2.5V. The discharge capacity is 161.8 mAh / g, as shown in Figure 3After charge-discharge activation under the above conditions, constant current-constant voltage charge-discharge is then carried out at a current of 1C. The charge-discharge process is as follows: first, constant current charge to 4.25V at a current of 1C and then constant voltage until the current is lower than 0.02C, and then discharge to 2.5V at a current of 1C. After 500 cycles, the capacity retention rate is 92.0%, as shown in Figure 4 。

[0076] Example 2

[0077] Preparation of solid electrolyte:

[0078] Na2Al2Si of Aladdin reagent 2.5 O9·nH2O zeolite (commercially available) is ion-exchanged in a 5mol / L aqueous LiCl solution. Among them, the average particle size of the zeolite is 400 nanometers, the specific surface area is 650m 2 / g, the ion-exchange temperature is 60°C, the ion-exchange time is 4 hours, and then it is dehydrated under 400 ℃ vacuum to obtain Li2Al2Si3O 10 。Li2Al2Si3O 10 is ball-milled and compounded with BiOCl. The ball-milling speed is 500rpm and the ball-milling time is 10 hours to obtain a zeolite solid electrolyte. Among them, the molar ratio of Li2Al2Si3O 10 to BiOCl is 0.5:1. After testing by alternating current impedance spectroscopy (frequency range 0.01~100000Hz, bias voltage 5mV), the ionic conductivity is 1.4×10 -4 S / cm. The electrochemical window of the solid electrolyte is measured to be 0.1~4.6V by linear sweep voltammetry (scan rate 0.1mV / s).

[0079] Preparation of solid-state lithium-ion battery:

[0080] S1 Preparation of negative electrode film:

[0081] Silicon-carbon containing 6wt% silicon, polytetrafluoroethylene and carbon nanotubes are mixed in a weight ratio of 94:2:4, and a negative electrode film is obtained by shear dispersion and roll pressing. The thickness of the negative electrode film is 62 microns.

[0082] S2 Preparation of solid electrolyte film:

[0083] The above solid electrolyte is mixed with polytetrafluoroethylene, and a solid electrolyte film is prepared by a dry method; among them, the weight ratio of the solid electrolyte to polytetrafluoroethylene is 100:1.5.

[0084] S3 Preparation of positive electrode film:

[0085] The LiCoO2 cathode, polytetrafluoroethylene, carbon nanotubes, and the above-mentioned solid electrolyte are dry-mixed in a weight ratio of 89:1.5:3.5:6, and are shear-dispersed and roll-pressed to obtain a cathode film.

[0086] S4 Preparation of a solid-state lithium-ion battery:

[0087] The negative electrode film, the solid electrolyte film, and the positive electrode film are laminated and encapsulated, and then an ionic liquid electrolyte, methyl methacrylate monomer, and azobisisobutyronitrile initiator are injected. A solid-state lithium-ion battery is obtained by in-situ polymerization at 60 °C for 60 minutes.

[0088] In the ionic liquid electrolyte, the ionic liquid is 1-propyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the lithium salt is LiTFSI, and the lithium salt concentration is 3 mol / L.

[0089] In the ionic liquid electrolyte, the weight ratio of the ionic liquid electrolyte to the methyl methacrylate monomer is 2:1, and the total weight of the ionic liquid electrolyte and the methyl methacrylate monomer to Li2Al2Si3O 10 is 0.1:1, and the weight ratio of the initiator to the methyl methacrylate monomer is 1:100. The relationship between the usage amount of the ionic liquid and the battery capacity is that the usage amount of the ionic liquid per Ah battery capacity is 0.7 grams.

[0090] According to the method of Example 1, the battery is subjected to a constant current-constant voltage test at room temperature in the voltage range of 2.5 to 4.3 V (1C is defined as 160 mA / g). The discharge capacity is 146.1 mAh / g, and the capacity retention rate is 94.3% after 500 cycles.

[0091] Example 3

[0092] Preparation of a solid electrolyte:

[0093] The Na2Al2Si 2.5 O9·nH2O zeolite (commercially available) of Aladdin reagent is subjected to ion exchange in a 5 mol / L aqueous LiCl solution. Among them, the average particle size of the zeolite is 400 nanometers, the specific surface area is 650 m 2 / g, the ion exchange temperature is 60 °C, the ion exchange time is 4 hours, and then it is vacuum dehydrated at 400 ℃ to obtain Li2Al2Si2O8. Li2Al2Si2O8 and BiOBr are ball-milled and compounded. The ball-milling speed is 500 rpm, and the ball-milling time is 10 hours to obtain a zeolite solid electrolyte. The molar ratio of Li2Al2Si2O8 to BiOBr is 1.5:1. After testing by AC impedance spectroscopy (frequency range 0.01 to 100000 Hz, bias voltage 5 mV), the ionic conductivity is 1.0×10 -4S / cm. The electrochemical window of the solid electrolyte was measured to be 0.1 - 4.65 V using linear sweep voltammetry (scan rate 0.1 mV / s).

[0094] Preparation of solid-state lithium-ion battery:

[0095] S1 Preparation of negative electrode film:

[0096] Silicon carbide containing 10 wt% silicon, polytetrafluoroethylene, and nanofiber carbon were mixed in a weight ratio of 95.5:1.5:3, and the negative electrode film was obtained through shear dispersion and roll pressing. The thickness of the negative electrode film was 58 microns.

[0097] S2 Preparation of solid electrolyte film:

[0098] The above solid electrolyte was mixed with polytetrafluoroethylene, and a solid electrolyte film was prepared using the dry method; among them, the weight ratio of the solid electrolyte to polytetrafluoroethylene was 100:2.

[0099] S3 Preparation of positive electrode film:

[0100] Li 1.2 Ni 0.18 Mn 0.62 The Li 1.2 Ni 0.18 Mn 0.62 O2 positive electrode, polytetrafluoroethylene, nanofiber carbon, and the above solid electrolyte were dry-mixed in a weight ratio of 89:1:4.5:5.5, and the positive electrode film was obtained through shear dispersion and roll pressing.

[0101] S4 Preparation of solid-state lithium-ion battery:

[0102] The negative electrode film, solid electrolyte film, and positive electrode film were laminated and encapsulated, and then an ionic liquid electrolyte, methyl methacrylate monomer, and azobisisobutyronitrile initiator were injected, and a solid-state lithium-ion battery was obtained through in-situ polymerization at 60°C for 60 minutes.

[0103] In the ionic liquid electrolyte, the ionic liquid was N-propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, the lithium salt was LiTFSI, and the lithium salt concentration was 2 mol / L.

[0104] The weight ratio of the ionic liquid electrolyte to the methyl methacrylate monomer was 4:1, the total weight ratio of the ionic liquid electrolyte and the methyl methacrylate monomer to the weight of Li2Al2Si2O8 was 0.5:1, and the weight ratio of the initiator to the methyl methacrylate monomer was 1:100. The relationship between the usage amount of the ionic liquid and the battery capacity was that the usage amount of the ionic liquid per Ah battery capacity was 1.1 grams.

[0105] According to the method of Example 1, the battery was subjected to a constant current-constant voltage test at room temperature in the voltage range of 2.5 to 4.6 V (1C is defined as 250 mA / g). The discharge capacity was 209.1 mAh / g, and the capacity retention rate was 90.2% after 500 cycles.

[0106] Example 4

[0107] Preparation of solid electrolyte:

[0108] Na2Al2Si of Aladdin reagent 2.5 O9·nH2O zeolite was ion-exchanged in 5 mol / L aqueous LiCl solution. The average particle size of the zeolite was 400 nm, the specific surface area was 650 m 2 / g, the ion-exchange temperature was 60 °C, the ion-exchange time was 4 hours, the ball-milling speed was 500 rpm, the ball-milling time was 10 hours, and then it was dehydrated under 400 ℃ vacuum to obtain Li2Al2Si 3.5 O 11 . Li2Al2Si 3.5 O 11 was ball-milled and compounded with ScOCl to obtain a zeolite solid electrolyte. The molar ratio of Li2Al2Si 3.5 O 11 to ScOCl was 0.6:1. After testing by AC impedance spectroscopy (frequency range 0.01 to 100000 Hz, bias voltage 5 mV), the ionic conductivity was 1.8×10 -4 S / cm. The electrochemical window of the solid electrolyte was measured to be 0.07 to 4.8 V by linear sweep voltammetry (scan rate 0.1 mV / s).

[0109] Preparation of solid-state lithium-ion battery:

[0110] S1 Preparation of negative electrode film:

[0111] Silicon-carbon containing 9 wt% silicon, polytetrafluoroethylene and Super P were mixed in a weight ratio of 94.5:1.5:4, and the negative electrode film was obtained by shear dispersion and rolling. The thickness of the negative electrode film was 54 μm.

[0112] S2 Preparation of solid electrolyte film:

[0113] The above solid electrolyte was mixed with polytetrafluoroethylene, and a solid electrolyte film was prepared by the dry method; among them, the weight ratio of the solid electrolyte to polytetrafluoroethylene was 100:1.5.

[0114] S3 Preparation of positive electrode film:

[0115] LiNi 0.7 Co 0.15 Mn0.15 The O2 cathode, polytetrafluoroethylene, carbon nanotubes and the above solid electrolyte are dry-mixed in a weight ratio of 91:1:3:5, and are subjected to shear dispersion and roll pressing to obtain a cathode film.

[0116] S4 Preparation of a solid-state lithium-ion battery:

[0117] The negative electrode film, the solid electrolyte film and the positive electrode film are laminated and encapsulated, and then an ionic liquid electrolyte, ethyl methacrylate monomer and azobisisobutyronitrile initiator are injected, and in-situ polymerization is carried out at 60 °C for 60 minutes to obtain a solid-state lithium-ion battery.

[0118] In the ionic liquid electrolyte, the ionic liquid is N-butyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide salt, the lithium salt is LiTFSI, and the lithium salt concentration is 1.5 mol / L.

[0119] The weight ratio of the ionic liquid electrolyte to the ethyl methacrylate monomer is 2.5:1, and the total weight of the ionic liquid electrolyte and the ethyl methacrylate monomer to Li2Al2Si 3.5 O 11 is 0.2:1, and the weight ratio of the initiator to the ethyl methacrylate monomer is 1:100. The relationship between the usage amount of the ionic liquid and the battery capacity is that the usage amount of the ionic liquid per Ah battery capacity is 0.9 grams.

[0120] According to the method of Example 1, the battery is subjected to room-temperature constant current-constant voltage test in the voltage range of 2.5 to 4.3 V (1C is defined as 200 mA / g), where the discharge capacity is 158.7 mAh / g, and the capacity retention rate is 90.7% after 500 cycles.

[0121] Comparative Example 1

[0122] FeOCl is not added to the solid electrolyte. That is, Li2Al2Si 2.5 O9 after vacuum dehydration is ball-milled in the same manner, and its ionic conductivity is 1.1×10 -6 S / cm. The electrochemical window of the solid electrolyte is measured by linear sweep voltammetry (scanning rate 0.1 mV / s) to be 0.2 to 4.2 V.

[0123] The solid electrolyte is used to replace the S2 solid electrolyte film in Example 1 and the solid electrolyte in S4 of Example 1 in the same method. The solid-state lithium battery prepared is subjected to electrochemical testing under the same conditions as in Example 1, and the discharge capacity is 122.3 mAh / g, and the capacity retention rate after 500 cycles is 82.5%. See Figure 5 .

[0124] Comparative Example 2

[0125] When preparing the solid electrolyte, Li2Al2Si 2.5 O9·nH2O is not dehydrated. After ball milling by the same method, the ionic conductivity of the solid electrolyte is measured to be 2.2×10 -6 S / cm. The electrochemical window of the solid electrolyte is measured to be 0.12 - 4.55 V by linear sweep voltammetry (scan rate 0.1 mV / s).

[0126] The S2 solid electrolyte membrane of Example 1 and the solid electrolyte in S4 of Example 1 are replaced with this solid electrolyte by the same method. The solid-state lithium battery prepared is electrochemically tested under the same conditions as Example 1, and the discharge capacity is 132.8 mAh / g, and the capacity retention rate after 500 cycles is 83.4%.

[0127] Comparative Example 3

[0128] The method for preparing the solid electrolyte is the same as that of Example 1, except that the molar ratio of Li2Al2Si 2.5 O9 to FeOCl is 2:1. After testing, the ionic conductivity is 2.5×10 -5 S / cm. The electrochemical window of the solid electrolyte is measured to be 0.1 - 4.33 V by linear sweep voltammetry (scan rate 0.1 mV / s).

[0129] The S2 solid electrolyte membrane of Example 1 and the solid electrolyte in S4 of Example 1 are replaced with this solid electrolyte by the same method. The solid-state lithium battery prepared is electrochemically tested under the same conditions as Example 1, and the discharge capacity is 134.0 mAh / g, and the capacity retention rate after 500 cycles is 84.1%.

[0130] Comparative Example 4

[0131] The method for preparing the solid electrolyte is the same as that of Example 1, except that the molar ratio of Li2Al2Si 2.5 O9 to FeOCl is 0.2:1. After testing, the ionic conductivity is 2.8×10 -6 S / cm. The electrochemical window of the solid electrolyte is measured to be 0.35 - 4.51 V by linear sweep voltammetry (scan rate 0.1 mV / s).

[0132] The S2 solid electrolyte membrane of Example 1 and the solid electrolyte in S4 of Example 1 are replaced with this solid electrolyte by the same method. The solid-state lithium battery prepared is electrochemically tested under the same conditions as Example 1, and the discharge capacity is 128.9 mAh / g, and the capacity retention rate after 500 cycles is 79.3%.

[0133] Comparative Example 5

[0134] The solid electrolyte is the same as that in Example 1.

[0135] The difference is that when preparing the solid-state lithium-ion battery, no ionic liquid electrolyte is added to the positive electrode, but a lithium salt is directly added, and the dosage of the lithium salt is the same as that in Example 1.

[0136] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1, with a discharge capacity of 125.5 mAh / g and a capacity retention rate of 82.8% after 500 cycles.

[0137] Comparative Example 6

[0138] The solid electrolyte is the same as that in Example 1.

[0139] The difference is that when preparing the solid-state lithium-ion battery, the weight ratio of the ionic liquid electrolyte to the ethyl acrylate monomer in the positive electrode is 1:1, that is, the dosage of ethyl acrylate remains unchanged, and the addition of the ionic liquid electrolyte is reduced.

[0140] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1, with a discharge capacity of 144.4 mAh / g and a capacity retention rate of 84.3% after 500 cycles.

[0141] Comparative Example 7

[0142] The solid electrolyte is the same as that in Example 1.

[0143] The difference is that when preparing the solid-state lithium-ion battery, the total weight of the ionic liquid electrolyte and the ethyl acrylate monomer in the positive electrode is in a weight ratio of 0.05:1 to Li2Al2Si 2.5 O9. That is, the dosage of the solid electrolyte is kept unchanged, and the dosages of the ionic liquid electrolyte and the ethyl acrylate monomer are reduced.

[0144] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1, with a discharge capacity of 138.7 mAh / g and a capacity retention rate of 83.7% after 500 cycles.

[0145] Comparative Example 8

[0146] The solid electrolyte is the same as that in Example 1.

[0147] The difference is that when preparing the solid-state lithium-ion battery, the ethyl acrylate monomer in the positive electrode is replaced with an equal amount of tetraethylene glycol dimethacrylate monomer.

[0148] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1, with a discharge capacity of 143.5 mAh / g and a capacity retention rate of 84.0% after 500 cycles.

[0149] Comparative Example 9

[0150] The solid electrolyte is the same as that in Example 1.

[0151] The difference is that when preparing the solid-state lithium-ion battery, in the ionic liquid electrolyte of the positive electrode, 1-butyl-3-methylimidazolium tetrafluoroborate is used to replace 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[0152] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1. The discharge capacity was 131.2 mAh / g, and the capacity retention rate after 500 cycles was 83.1%.

[0153] Comparative Example 10

[0154] The solid electrolyte is the same as that in Example 1.

[0155] The difference is that when preparing the solid-state lithium-ion battery, no solid electrolyte is added to the positive electrode.

[0156] The solid-state lithium battery prepared by this method was electrochemically tested under the same conditions as in Example 1. The discharge capacity was 141.9 mAh / g, and the capacity retention rate after 500 cycles was 83.9%.

[0157] Examples 5 to 7 and Comparative Examples 11 to 12

[0158] It is consistent with the solid electrolyte formula of Example 1, but the difference is that the rotation speed and time of ball milling are adjusted. The measured ionic conductivity and electrochemical window data are shown in Table 1.

[0159] Table 1

[0160]

[0161] It can be seen from Comparative Example 11 and Comparative Example 12 that when the rotation speed is too low, it will cause a significant decrease in the ionic conductivity of the solid electrolyte and a decrease in the electrochemical window. The discharge capacity and long-term cycling performance of the solid-state lithium battery assembled with this solid electrolyte under the same conditions as in Example 1 also show a significant decrease.

[0162] It can be seen from Example 7 that if the ball milling time is extended, it may also lead to a decrease in ionic conductivity, thereby causing a decrease in the discharge capacity and long-term cycling performance of the assembled solid-state lithium battery.

[0163] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A solid electrolyte, characterized in that, It is obtained by ball-milling and mixing a lithium-containing zeolite and a metal halogen oxide; the lithium-containing zeolite is obtained by subjecting a sodium-containing zeolite to lithium ion exchange and performing vacuum dehydration treatment; The molar ratio of lithium to the metal halogen oxide in the lithium-containing zeolite is 1 to 3:1; The chemical formula of the lithium-containing zeolite is Li2Al2Si 2+x O 8+2x , where 0 ≤ x ≤ 3; The metal in the metal halogen oxide is selected from at least one of Bi, Al, Fe, V, In, Cr, Sc, La, and Sm; The rotation speed of the ball milling is not less than 400 rpm.

2. The solid electrolyte according to claim 1, characterized in that, The rotation speed of the ball milling is 400 to 600 rpm, and the ball milling time is 8 to 25 hours.

3. The solid electrolyte according to claim 1, characterized in that, The temperature of the vacuum dehydration treatment is 300 to 500 °C.

4. The solid electrolyte according to claim 1, characterized in that, The time of the vacuum dehydration is 1 to 10 hours.

5. The solid electrolyte according to claim 1, characterized in that, The particle size of the lithium-containing zeolite is 100 to 500 nanometers, and the specific surface area is 300 to 800 m 2 / g.

6. A solid-state lithium-ion battery, characterized in that, It includes a silicon-based negative electrode, the solid electrolyte according to any one of claims 1 to 5, a positive electrode, and a polymer network and an ionic liquid electrolyte distributed throughout the battery.

7. The solid-state lithium-ion battery according to claim 6, wherein, The polymer network is formed from acrylate monomers.

8. The solid-state lithium-ion battery according to claim 6, characterized in that, The ionic liquid electrolyte includes an ionic liquid and a lithium salt.

9. The solid-state lithium-ion battery according to claim 8, wherein, The anion of the ionic liquid is selected from bis(trifluoromethanesulfonyl)imide anions; the cation of the ionic liquid is selected from one or more of pyrrole-based, piperidine-based, or imidazole-based cations.

10. The method for preparing a solid-state lithium-ion battery according to any one of claims 6 to 9, characterized in that, It includes the following steps: Preparing a negative electrode film; Preparing the solid electrolyte according to any one of claims 1 to 5 and forming it into a solid electrolyte film; Preparing a positive electrode film; Stacking, encapsulating the negative electrode film, the solid electrolyte film, and the positive electrode film, then injecting the ionic liquid electrolyte, the polymer monomer for forming the polymer network, and an initiator, and performing an in-situ polymerization reaction to obtain the solid-state lithium-ion battery.

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