A semi-gel electrolyte and its preparation method

Abstract

The present invention belongs to the field of lithium ion batteries, and discloses a semi-gel electrolyte and a preparation method thereof. The present invention is a method for forming "inorganic-organic" modified particles by chemical reaction of inorganic particles whose surfaces are polluted by air with ordinary organic liquids. The particles have a long chain structure, and the poor contact and unusable inorganic particles caused by the original pollution can form a dense and uniform interface lithium migration channel in the composite electrolyte after modification. The semi-gel electrolyte prepared by the present invention has higher lithium ion conductivity, good high-voltage stability and cycle stability, and can reach an actual specific capacity of 155.1mAh / g at 0.5C, accounting for 91.2% of the theoretical specific capacity (170mAh / g). Embodiments 1 and 3 can maintain more than 138mAh / g after 100 cycles, and are an excellent electrolyte that can be widely used in polymer gel batteries.

Description

Technical Field

[0001] The present invention belongs to the field of lithium ion batteries, and in particular relates to a semi-gel electrolyte and a preparation method thereof. Background Art

[0002] Lithium-ion batteries are a type of secondary battery (rechargeable battery) widely used in many fields. The presence of an electrolyte allows lithium ions to move between the positive and negative electrodes, enabling the battery to function. As lithium-ion battery manufacturing technology has gradually improved, some lithium-ion batteries have been developed using solid electrolytes, namely gel electrolytes or semi-gel electrolytes. In Chinese patent publication CN112670566 A, Wang Peng et al. disclose a polymer-matrix electrolyte composed of multiple organic matrices, lithium salts, and plasticizers. The electrolyte consists of four main components: a main monomer that provides a transmission channel, a softener that increases the flexibility of the polymer chain, a cross-linker that improves mechanical strength, and a high-voltage stabilizer that provides high-voltage stability. The optimal material achieves a capacity retention rate of 96.3% after 200 cycles of Coulomb cycling at room temperature and 0.5°C. However, it requires additional support from PAN non-woven fabric, which is susceptible to dehydrocyanation and reaction with lithium, forming a thick passivation layer that affects performance. In Chinese patent publication CN114300742 A, the corresponding solid electrolyte uses an appropriate amount of inorganic additives in addition to the organic matrix, but the ionic conductivity is insufficient, at only 0.9 mS / cm. Furthermore, in both patents, the organic polymer and inorganic additives are only physically combined by stirring, which has limited effectiveness.

[0003] Therefore, the present invention modifies the semi-gel electrolyte by adding inorganic substances to improve the comprehensive performance of the semi-gel electrolyte. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a semi-gel electrolyte.

[0005] Another object of the present invention is to provide a semi-gel electrolyte prepared by the above method.

[0006] The purpose of the present invention is achieved through the following solutions:

[0007] A method for preparing a semi-gel electrolyte comprises the following steps:

[0008] (1) Mixing metal oxides with cyclic organic liquids to generate inorganic-organic particles;

[0009] (2) dissolving the first lithium salt in the organic monomer, adding a softener and an initiator, and stirring and mixing to form a solution A;

[0010] (3) dissolving the second lithium salt in the plasticizer, adding an organic ligand and a surface stabilizer, stirring and dissolving at 35-50° C., cooling to room temperature and stirring, adding the inorganic-organic particles and / or inorganic particles, ultrasonically dispersing them uniformly, and continuing stirring to form solution B;

[0011] (4) Slowly dripping the solution B into the stirring solution A until all the solution is added, continuing to stir at room temperature, and casting on a polytetrafluoroethylene mold to initiate in-situ polymerization to form a film while controlling the viscosity to a certain level without gelation;

[0012] (5) After the film is formed, it is cooled and cut into pieces to obtain a semi-gel electrolyte membrane.

[0013] The metal oxide in step (1) is a complex metal oxide that has been left in the air for more than 1 day and has been contaminated;

[0014] Preferably, the surface of the metal oxide contains lithium hydroxide and / or lithium carbonate;

[0015] Preferably, the metal oxide is selected from at least one of lithium lanthanum zirconium tantalum oxide (LLZTO), lithium lanthanum tantalum oxide (LLTO), and lithium lanthanum zirconium oxide (LLZO);

[0016] Further preferably, the metal oxide particle size is between 200nm-10um;

[0017] The organic liquid in step (1) is ethylene carbonate (EC), vinylene carbonate (VC), sulfolene (BS) or one or more of the above organic liquids with single or multiple halogen (except F) substituted organic compounds;

[0018] The mass ratio of the oxide to the organic liquid in step (1) is 2:1-1:10;

[0019] Preferably, the mixing in step (1) refers to mixing and reacting at 70-100° C. for 18-30 hours;

[0020] The first lithium salt in step (2) includes any one or more of lithium bis(trifluoromethylimide) (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate;

[0021] The organic monomer in step (2) includes any one or more of acrylic acid (AA), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), vinylene carbonate (VC), acrylonitrile (AN), sulfone (BS) or mono- or poly-halogenated compounds (X=F, Cl, Br, I) of the above molecules;

[0022] The concentration of the first lithium salt in step (2) is 0.5-1 mol / L, wherein the first lithium salt concentration is based on the concentration of the lithium salt dissolved in the organic monomer, that is, the molar concentration of the first lithium salt after dissolving in the organic monomer;

[0023] The softener in step (2) includes one or more of polyethylene glycol diacrylate (PEGDA), polyethylene glycol monoacrylate (PMGDA), etc.;

[0024] Preferably, the molecular weight of the softener is 200-800;

[0025] More preferably, the molecular weight of the softener is any one of 200, 400, 600 or 800;

[0026] The amount of the softener added in step (2) is 0.5-5.0% of the mass fraction of the organic monomer; the initiator is preferably azobisisobutyronitrile (AIBN), and the amount of the initiator added is 0.1%-2% of the mass fraction of the organic monomer and the softener;

[0027] Preferably, the solution A in step (2) is a thin oily liquid;

[0028] The plasticizer in step (3) is preferably succinonitrile (SN);

[0029] In step (3), the second lithium salt includes any one or more of lithium bis(trifluoromethylimide) (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate;

[0030] Preferably, the dissolution temperature in step (3) is greater than or equal to the melting point of the plasticizer; the surface stabilizer in step (3) is preferably fluoroethylene carbonate (FEC);

[0031] Preferably, the amount of the surface stabilizer is 5-8% of the mass of the plasticizer;

[0032] The organic ligand in step (3) is polyethylene glycol (PEG) and / or polyethylene oxide (PEO);

[0033] Preferably, the organic ligand is polyethylene glycol with a molecular weight of 200-800, and / or polyethylene oxide with a molecular weight of 500,000-600,000;

[0034] More preferably, the molecular weight of the polyethylene glycol is any one of 200, 400, 600 or 800, and the molecular weight of the polyethylene oxide is 500,000 or 600,000;

[0035] The mass ratio of the plasticizer to the organic complexing agent in step (3) is (2-10):1;

[0036] In step (3), the mass ratio of the organic monomer in solution A to the plasticizer in solution B is (3-5):2;

[0037] In step (3), the concentration of the second lithium salt is 0.5-1 mol / L; the concentration of the second lithium salt is based on the concentration of the lithium salt dissolved in the plasticizer and the organic ligand, that is, the molar concentration of the second lithium salt after dissolving in the plasticizer and the organic ligand, and when the plasticizer is solid, its volume is the volume of the liquid formed at the corresponding melting point temperature;

[0038] Preferably, the stirring and dissolving in step (3) refers to stirring until the liquid is clear;

[0039] In step (3), the mass ratio of the amount of "inorganic-organic" added to the organic complexing agent is 1:2-1:6, or the inorganic particles are added with a total mass fraction of 0.5%-12.5%;

[0040] The inorganic particles include any one or more of silicon dioxide, aluminum oxide, or the complex metal oxides mentioned in step (1);

[0041] Preferably, the inorganic particles are of nanometer or micrometer size;

[0042] The viscosity in step (4) is 600-1000 mPa·s;

[0043] The polymerization temperature in step (4) is 70-80° C., and the polymerization time is 2-16 h.

[0044] The above methods are all carried out in a protective atmosphere.

[0045] The present invention prepares solutions A and B separately and then slowly pours solution B into solution A, resulting in a semi-gel electrolyte with high lithium ion conductivity, good high-voltage stability, and cyclic stability. However, if solutions A and B are initially mixed and stirred, the liquid in solution B will not participate in the reaction, which would prolong the time it takes for the organic monomers to form oligomers at a certain concentration and increase the amount of initiator required. Furthermore, the collisions between the organic monomers in solution A are too random, leading to an increased distribution of oligomers. Furthermore, nanometer-scale inorganic particles tend to aggregate and stratify in liquids with low viscosity. Combined with these factors, membranes prepared by initially mixing solutions A and B exhibit poor performance. Furthermore, after reaching a certain viscosity, contact between the inorganic particles must overcome the surface potential of the mucus, making aggregation difficult. Therefore, solutions A and B must be prepared separately from the beginning. A comparison of the performance of Example 1 and Comparative Example 2 reveals that Comparative Example 2 is less stable than Example 1, further demonstrating the necessity of preparing solutions A and B separately.

[0046] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0047] (1) The semi-gel electrolyte prepared by the present invention has high lithium ion conductivity, good high-voltage stability and cycle stability. At 0.5C, it can reach an actual specific capacity of 155.1 mAh / g, and the coulombic efficiency accounts for 91.2% of the theoretical specific capacity (170 mAh / g). Examples 1 and 3 can maintain above 138 mAh / g after 100 cycles. It is an excellent electrolyte and can be widely used in polymer gel batteries.

[0048] (2) The present invention forms "inorganic-organic" modified particles with a long-chain structure by chemically reacting inorganic particles with organic liquids, so that inorganic particles that were originally contaminated and had poor contact and could not be used can form dense and uniform interfacial lithium migration channels in the composite electrolyte after modification; the present invention modifies the semi-gel electrolyte through physical and chemical reactions, thereby improving the lithium ion conductivity, high-voltage stability and cycle stability of the semi-gel electrolyte.

[0049] (3) The "inorganic-organic" particles described in the present invention, due to their end group specificity and long chain segment structure, can connect the polymerized polymer and the dispersed inorganic particles, avoiding the risk of phase separation and the formation of "channel traps" for lithium ions. "Channel traps" will cause the electrolyte membrane to easily form local lithium accumulation in the inorganic particle portion during charge and discharge, while the organic polymer chain segment has no lithium salt for ions to flow, resulting in a decrease in electrochemical performance. Therefore, the "inorganic-organic" particles in the electrolyte membrane of the present invention act as "channel hubs", allowing lithium ions to be transported as far as possible to the other electrode for reduction, thereby maintaining a good level of performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The first-cycle interface impedance diagram of the electrolyte membranes prepared in Comparative Examples 1 and 2 and Examples 1 and 3 in lithium symmetric batteries;

[0051] Figure 2 The electrolyte membranes prepared in Comparative Examples 1 and 2 and Examples 1 and 3 were tested for battery performance after 100 cycles at 0.5C coulombic cycles with lithium iron phosphate: carbon black: PVDF = 8:1:1 as the positive electrode and lithium sheet as the negative electrode. DETAILED DESCRIPTION

[0052] The present invention will be described in further detail below with reference to the Examples and accompanying drawings, but the embodiments of the present invention are not limited thereto. Where specific conditions are not specified in the Examples, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0053] Unless otherwise specified, all reagents used in the examples can be purchased from the market.

[0054] The reactions in the examples and comparative examples were all carried out in an argon atmosphere.

[0055] Example 1 (with "inorganic-organic particles", without inorganic particles, separate solutions A and B)

[0056] The synthesis method of "inorganic-organic particles" (EC-LLZTO) is as follows: 0.16612g (0.19mmol) of LLZTO with a particle size of 2.26μm, which has been contaminated by air (humidity: 65%, temperature: 25°C) for 12 hours, and 0.91259g (10.36mmol) of EC are weighed into a small bottle, stirred at 100°C for 24 hours, and then cooled.

[0057] Liquid A part: Weigh BA 2.4950 g (19.47 mmol), AN 0.5626 g (10.60 mmol), VC 1.1336 g (13.17 mmol), PEGDA-400 0.1168 g (0.29 mmol), AIBN 0.0409 g (0.25 mmol), LiTFSI 1.2919 g (4.50 mmol), LiFSI 0.2105 g (1.13 mmol), add to a small bottle, stir at room temperature for 10 min, and then open the lid.

[0058] Solution B: Weigh 2.4625 g (30.75 mmol) of SN, 0.1818 g (1.71 mmol) of FEC, 0.7879 g (1.97 mmol) of PEG400, 0.0415 g of PEO-600000, 1.223 g (4.26 mmol) of LiTFSI, and 0.2003 g (1.07 mmol) of LiFSI. Stir the mixture at 40°C for 20 min, cool to room temperature, and stir for another 30 min. Stop stirring and add the mixture to the cooled EC-LLZTO vial. Ultrasonicate and disperse the mixture evenly. Continue stirring to form solution B.

[0059] Liquid B was slowly added to the stirring liquid A with a pipette. After the addition was complete, it was stirred for 50 minutes and then cast on a polytetrafluoroethylene mold. It was heated at 70°C for 2.5 hours to form a film. After the film was taken out, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0060] The semi-gel electrolyte membrane prepared in this example has a -4 S / cm, the excellent ionic conductivity, the actual specific capacity is stable at 151.3mAh / g, and it maintains a high specific capacity of 138.6mAh / g after 100 cycles.

[0061] Example 2 (without "inorganic-organic particles", with inorganic particles, separate solutions A and B)

[0062] Liquid A part: Weigh BA 2.4950 g (19.47 mmol), AN 0.5626 g (10.60 mmol), VC 1.1336 g (13.17 mmol), PEGDA-400 0.1168 g (0.29 mmol), AIBN 0.0409 g (0.25 mmol), LiTFSI 1.2919 g (4.50 mmol), LiFSI 0.2105 g (1.13 mmol), add to a small bottle, stir at room temperature for 10 min, and then open the lid.

[0063] Solution B: Weigh 2.4625 g (30.75 mmol) of SN, 0.1818 g (1.71 mmol) of FEC, 0.7879 g (1.97 mmol) of PEG400, 0.0415 g of PEO-600000, 1.223 g (4.26 mmol) of LiTFSI, and 0.2003 g (1.07 mmol) of LiFSI. Stir the mixture at 40°C for 20 min, cool the mixture to room temperature, and stir for another 30 min. Stop stirring, add 0.0598 g (0.99 mmol) of 200 nm inorganic particles of SiO2, and disperse the mixture evenly by ultrasonication. Continue stirring to form solution B.

[0064] Liquid B was slowly added to the stirring liquid A with a pipette. After the addition was complete, it was stirred for 50 minutes and then cast on a polytetrafluoroethylene mold. It was heated at 70°C for 2.5 hours to form a film. After the film was taken out, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0065] The ionic conductivity of the semi-gel electrolyte membrane prepared in this example is 4.656×10 -4 S / cm, and the actual specific capacity is stable at 145.23mAh / g.

[0066] Example 3 (with "inorganic-organic particles", with inorganic particles, and separate A and B solutions)

[0067] The synthesis method of “inorganic-organic particles” (EC-LLZTO) is the same as the preparation method in Example 1.

[0068] Liquid A part: Weigh BA 2.4950 g (19.47 mmol), AN 0.5626 g (10.60 mmol), VC 1.1336 g (13.17 mmol), PEGDA-400 0.1168 g (0.29 mmol), AIBN 0.0409 g (0.25 mmol), LiTFSI 1.2919 g (4.50 mmol), LiFSI 0.2105 g (1.13 mmol), and inorganic particles SiO2 with a particle size of 200 nm 0.0585 g (0.97 mmol) were added to a small bottle and stirred at room temperature for 10 min.

[0069] Solution B: Weigh 2.4625 g (30.75 mmol) of SN, 0.1818 g (1.71 mmol) of FEC, 0.7879 g (1.97 mmol) of PEG400, 0.0415 g of PEO-600000, 1.223 g (4.26 mmol) of LiTFSI, and 0.2003 g (1.07 mmol) of LiFSI. Stir at 40°C for 20 min, cool to room temperature, and stir for an additional 30 min. Stop stirring. Add the mixture to the cooled EC-LLZTO vial. Add 0.0598 g (0.99 mmol) of SiO2 with a particle size of 200 nm. Disperse uniformly by ultrasonication. Continue stirring to form Solution B.

[0070] Liquid B was slowly added to the stirring liquid A with a pipette. After the addition was complete, it was stirred for 50 minutes and then cast on a polytetrafluoroethylene mold. It was heated at 70°C for 2.5 hours to form a film. After the film was taken out, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0071] The ionic conductivity of the semi-gel electrolyte membrane prepared in this example is 1.066×10 -3 S / cm, the actual specific capacity is stable at 155.1mAh / g, and the actual specific capacity is 143.5mAh / g after 100 cycles.

[0072] Comparative Example 1 (without "inorganic-organic particles" or inorganic particles, and separate solutions A and B)

[0073] Liquid A part: Weigh BA 2.4950 g (19.47 mmol), AN 0.5626 g (10.60 mmol), VC 1.1336 g (13.17 mmol), PEGDA-400 0.1168 g (0.29 mmol), AIBN 0.0409 g (0.25 mmol), LiTFSI 1.2919 g (4.50 mmol), LiFSI 0.2105 g (1.13 mmol), add to a small bottle, stir at room temperature for 10 min, and then open the lid.

[0074] Solution B: Weigh 2.4625 g (30.75 mmol) of SN, 0.1818 g (1.71 mmol) of FEC, 0.7879 g (1.97 mmol) of PEG400, 0.0415 g of PEO-600000, 1.223 g (4.26 mmol) of LiTFSI, and 0.2003 g (1.07 mmol) of LiFSI, add the mixture to a small bottle, stir at 40°C for 20 min, cool to room temperature, and stir for another 30 min. Stop stirring to form solution B.

[0075] Liquid B was slowly added to the stirring liquid A with a pipette. After the addition was complete, it was stirred for 50 minutes and then cast on a polytetrafluoroethylene mold. It was heated at 70°C for 2.5 hours to form a film. After the film was taken out, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0076] The ionic conductivity of the semi-gel electrolyte membrane prepared in this comparative example is 1.028×10 -4 S / cm, and the actual specific capacity is 123.2mAh / g.

[0077] Comparative Example 2 (with "inorganic-organic particles", without inorganic particles, and liquids A and B not separated)

[0078] The synthesis method of “inorganic-organic particles” (EC-LLZTO) is the same as the preparation method in Example 1.

[0079] Weigh BA 2.4950g (19.47mmol), AN 0.5626g (10.60mmol), VC 1.1336g (13.17mmol), PEGDA-400 0.1168g (0.29mmol), AIBN 0.0409g (0.25mmol), SN 2.4625g (30.75mmol), FEC 0.1818g (1.71mmol), PEG400 0.7879g (1.97mmol), PEO-6000000.0415g, LiFSI 0.4107g (2.20mmol), LiTFSI 2.5144 g (8.759 mmol) was added to a bottle containing "inorganic-organic" ("EC-LLZTO") after the reaction was completed and cooled to room temperature. After stirring for 1 hour, it was poured on a polytetrafluoroethylene mold and heated at 70°C for 2.5 hours to form a film. After taking out the film, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0080] The ionic conductivity of the semi-gel electrolyte membrane prepared in this comparative example is 2.462×10 -4 S / cm, and the actual specific capacity is 144.9mAh / g.

[0081] Comparative Example 3 (without "inorganic-organic particles" or inorganic particles, mixture of liquids A and B)

[0082] Weigh BA2.4950g (19.47mmol), AN 0.5626g (10.60mmol), VC 1.1336g (13.17mmol), PEGDA-400 0.1168g (0.29mmol), AIBN 0.0409g (0.25mmol), SN 2.4625g (30.75mmol), FEC0.1818g (1.71mmol), PEG400 0.7879g (1.97mmol), PEO-600000 0.0415g, LiFSI 0.4107g (2.20mmol), LiTFSI 2.5144 g (8.759 mmol) was stirred for 1 h, poured onto a polytetrafluoroethylene mold, and heated at 70°C for 2.5 h to form a membrane. The membrane was taken out and cut with a punch of 16 mm in diameter to obtain the corresponding semi-gel electrolyte membrane.

[0083] The ionic conductivity of the semi-gel electrolyte membrane prepared in this comparative example is 8.017×10 -5 S / cm, and the actual specific capacity is 114mAh / g.

[0084] Comparative Example 4 (without "inorganic-organic particles", with inorganic particles, and liquids A and B are not separated)

[0085] Weigh BA 2.4950g (19.47mmol), AN 0.5626g (10.60mmol), VC 1.1336g (13.17mmol), PEGDA-400 0.1168g (0.29mmol), AIBN 0.0409g (0.25mmol), SN 2.4625g (30.75mmol), FEC 0.1818g (1.71mmol), PEG400 0.7879g (1.97mmol), PEO-6000000.0415g, LiFSI 0.4107g (2.20mmol), LiTFSI 2.5144 g (8.759 mmol) and 0.0585 g (0.97 mmol) of SiO2 with a particle size of 200 nm were stirred for 1 hour and then cast on a polytetrafluoroethylene mold. After heating at 70°C for 2.5 hours, a film was formed. After the film was taken out, it was cut with a punch with a diameter of 16 mm to obtain the corresponding semi-gel electrolyte membrane.

[0086] The ionic conductivity of the semi-gel electrolyte membrane prepared in this comparative example is 1.115×10 -4 S / cm, and the actual specific capacity is 120mAh / g.

[0087] Table 1 shows the first-cycle ionic conductivity of the electrolyte membranes prepared in Comparative Examples 1 and 2 and Examples 1 and 3 in 500 μm thick lithium symmetric batteries.

[0088] Comparing Examples 1 and 3 with Comparative Examples 1 and 2, and combining Table 1, Figure 1 and Figure 2 It can be seen that Comparative Example 1 is actually a blank sample (without "inorganic-organic" particles) compared to Comparative Example 2 and Examples 1 and 3, with the highest AC impedance and the lowest ionic conductivity, and the lowest actual specific capacity. The second is Comparative Example 2, which directly mixes "A" and "B" liquids (without separation). By comparing the performance of Examples 1 and 2, the necessity of separating A and B liquids is further confirmed. Obviously, the stability of Comparative Example 2 is worse than that of Example 1. Example 1 is a sample with normal "EC-LLZTO" added, with a specific capacity of 7.059×10 -4 S / cm and a high specific capacity of 138.6 mAh / g after 100 cycles. After further adding 1% of 200 nm silica to the comparative example 1, the ionic conductivity is further improved to 1.066×10 -3 S / cm and an excellent performance of an actual specific capacity of 143.5 mAh / g after 100 cycles.

[0089] Table 1 First-cycle ionic conductivity and specific capacity of various examples

[0090]

[0091] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a semi-gel electrolyte, characterized in that The following steps are involved: (1) Mixing metal oxides with cyclic organic liquids to generate "inorganic-organic" particles; (2) dissolving the first lithium salt in the organic monomer, adding a softener and an initiator, and stirring and mixing to form a solution A; (3) dissolving the second lithium salt in the plasticizer, adding an organic ligand and a surface stabilizer, stirring and dissolving at 35-50°C, cooling to room temperature and stirring, adding the "inorganic-organic" particles and / or inorganic particles, ultrasonically dispersing them uniformly, and continuing to stir to form solution B; (4) Slowly dripping the solution B into the stirring solution A until all the solution is added, continuing to stir at room temperature, and pouring the solution onto a polytetrafluoroethylene mold to initiate in-situ polymerization to form a film while controlling the viscosity to a certain level without gelation; (5) After the film is formed, it is cooled and cut into pieces to obtain a semi-gel electrolyte membrane; The metal oxide in step (1) is selected from at least one of lithium lanthanum zirconium tantalum oxide, lithium lanthanum tantalum oxide, and lithium lanthanum zirconium oxide; The organic liquid in step (1) is ethylene carbonate, vinylene carbonate, cyclobutane sulfone or one or more of the above organic liquids except F and a single or multiple halogen substituted organic compound; The mixing in step (1) refers to mixing and reacting at 70-100°C for 18-30 hours; The inorganic particles in step (3) include any one or more of silicon dioxide, aluminum oxide, or the metal oxides mentioned in step (1).

2. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The metal oxide in step (1) is a complex metal oxide that has been left in the air for more than 1 day and has been contaminated.

3. The method for preparing a semi-gel electrolyte according to claim 2, wherein: The surface of the metal oxide contains lithium hydroxide and / or lithium carbonate.

4. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The particle size of the metal oxide is between 200nm and 10um.

5. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The mass ratio of the metal oxide to the organic liquid in step (1) is 2:1-1:

10.

6. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The first lithium salt in step (2) includes any one or more of lithium bis(trifluoromethylimide), lithium bis(fluorosulfonylimide), lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate; The organic monomers in step (2) include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, vinylene carbonate, acrylonitrile, cyclobutane sulfone or any one or more of the mono- or poly-halogenated compounds of the above molecules.

7. The method for preparing a semi-gel electrolyte according to claim 6, wherein: The halogen in the mono- or poly-halogenated organic monomer is F, Cl, Br or I.

8. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The concentration of the first lithium salt in step (2) is 0.5-1 mol / L, wherein the first lithium salt concentration is based on the concentration of the lithium salt dissolved in the organic monomer, that is, the molar concentration of the first lithium salt after dissolving in the organic monomer; The softener in step (2) includes one or more of polyethylene glycol diacrylate and polyethylene glycol monoacrylate.

9. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The molecular weight of the softener is 200-800.

10. The method for preparing a semi-gel electrolyte according to claim 9, characterized in that: The molecular weight of the softener is any one of 200, 400, 600 or 800.

11. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The amount of the softener added in step (2) is 0.5-5.0% of the mass fraction of the organic monomer; the initiator is azobisisobutyronitrile, and the amount of the initiator added is 0.1%-2% of the mass fraction of the organic monomer and the softener.

12. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: The solution A in step (2) is a thin oily liquid; the plasticizer in step (3) is succinonitrile; The second lithium salt in step (3) includes any one or more of lithium bis(trifluoromethylimide), lithium bis(fluorosulfonylimide), lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate.

13. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: The dissolution temperature in step (3) is greater than or equal to the melting point of the plasticizer.

14. The method for preparing a semi-gel electrolyte according to claim 1, wherein: The surface stabilizer in step (3) is fluoroethylene carbonate.

15. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: The amount of the surface stabilizer is 5-8% of the mass of the plasticizer; The organic ligand in step (3) is polyethylene glycol and / or polyethylene oxide.

16. The method for preparing a semi-gel electrolyte according to claim 15, characterized in that: The organic ligand is selected from polyethylene glycol with a molecular weight of 200-800 and / or polyethylene oxide with a molecular weight of 500,000-600,000.

17. The method for preparing a semi-gel electrolyte according to claim 16, characterized in that: The molecular weight of the polyethylene glycol is any one of 200, 400, 600 or 800, and the molecular weight of the polyethylene oxide is 500,000 or 600,000.

18. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: The mass ratio of the plasticizer to the organic ligand in step (3) is (2-10):1; In step (3), the mass ratio of the organic monomer in solution A to the plasticizer in solution B is (3-5):2; The concentration of the second lithium salt in step (3) is 0.5-1 mol / L; the concentration of the second lithium salt is based on the concentration of the lithium salt dissolved in the plasticizer and the organic ligand, that is, the molar concentration of the second lithium salt after dissolving in the plasticizer and the organic ligand, and when the plasticizer is solid, its volume is the volume of the liquid formed at the corresponding melting point temperature.

19. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: In step (3), the mass ratio of the amount of "inorganic-organic" added to the organic complexing agent is 1:2-1:6, or the inorganic particles are added with a total mass fraction of 0.5%-12.5%.

20. The method for preparing a semi-gel electrolyte according to claim 1, characterized in that: The inorganic particles are of nanometer or micrometer level; The viscosity in step (4) is 600-1000 mPa·s; The polymerization temperature in step (4) is 70-80° C., and the polymerization time is 2-16 h.

21. A semi-gel electrolyte, characterized in that: A semi-gel electrolyte prepared by the method according to any one of claims 1 to 20.

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