Preparation method of gel quasi-solid electrolyte and gel quasi-solid electrolyte and lithium ion battery

Abstract

The application provides a preparation method of a gel quasi-solid electrolyte and the gel quasi-solid electrolyte and a lithium ion battery, and relates to the technical field of electrochemistry. The preparation method of the gel quasi-solid electrolyte comprises the following steps: mixing polyether polyol, isocyanate, a catalyst and inorganic fillers, and obtaining a gel intermediate after reaction; soaking the gel intermediate in fluorine-containing organic matter to obtain a capped intermediate; wherein the fluorine-containing organic matter is selected from one or more of fluorine-containing acid anhydride, fluorine-containing isocyanate and fluorine-containing acyl halide; and soaking the capped intermediate in an electrolyte to obtain the gel quasi-solid electrolyte after swelling. The preparation method of the gel quasi-solid electrolyte provided by the application is simple in operation and convenient to prepare, and can prepare the gel quasi-solid electrolyte with high liquid absorption rate and high voltage resistance.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, specifically to a method for preparing gel quasi-solid electrolytes and to gel quasi-solid electrolytes and lithium-ion batteries. Background Technology

[0002] As a crucial component of lithium-ion batteries, the electrolyte is a key factor influencing battery performance. Currently, commonly used liquid electrolytes in lithium-ion batteries contain flammable organic solvents, which are prone to leakage during long-term use, leading to serious safety issues. To improve the safety of lithium-ion batteries, one approach is to use solid-state electrolytes instead of liquid electrolytes. Solid-state electrolytes can also effectively suppress the formation and growth of lithium metal anode dendrites, making them promising for application in lithium metal batteries and further improving battery energy density and safety performance.

[0003] Currently, solid electrolytes mainly include polymer electrolytes and inorganic solid electrolytes. Polymer electrolytes primarily include systems based on polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA). Comparatively, the main disadvantages of polymer electrolytes are lower room-temperature ionic conductivity and a narrower electrochemical window. Inorganic solid electrolytes include sulfide solid electrolytes and oxide solid electrolytes. The main disadvantages of inorganic solid electrolytes include poor interface between the electrolyte and electrode and poor processability.

[0004] To address the aforementioned issues, gel quasi-solid electrolytes have attracted widespread attention. These typically consist of a polymer matrix, an electrolyte, and additives. Gel quasi-solid electrolytes combine the advantages of liquid and solid electrolytes. The polymer matrix, formed through physical or chemical processes, can effectively adsorb the electrolyte, reducing the risk of leakage. Simultaneously, gel quasi-solid electrolytes can balance performance indicators such as ionic conductivity, interfacial compatibility with electrodes, and cycle stability, exhibiting excellent overall performance. However, currently reported gel quasi-solid electrolytes have low liquid uptake rates, and adsorbing the electrolyte requires a considerable mass of polymer matrix, inevitably reducing the battery's energy density. Furthermore, existing gel quasi-solid electrolytes have narrow electrochemical windows, are not resistant to high voltages, and are prone to decomposition in electrodes (especially ternary cathode materials). Therefore, developing gel quasi-solid electrolytes with high liquid uptake rates and high voltage tolerance is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a gel quasi-solid electrolyte. This method is simple to operate, convenient to prepare, and can produce a gel quasi-solid electrolyte with high liquid absorption rate and high voltage tolerance.

[0006] Another objective of this invention is to provide a gel quasi-solid electrolyte with high liquid absorption rate, good high voltage tolerance, and excellent overall performance.

[0007] Another object of the present invention is to provide a lithium-ion battery.

[0008] The technical problem solved by this invention is achieved by the following technical solution:

[0009] Methods for preparing gel quasi-solid electrolytes include:

[0010] A gel intermediate is obtained by mixing polyether polyol, isocyanate, catalyst and inorganic filler and reacting.

[0011] A gel intermediate is immersed in a fluorinated organic compound to obtain a capping intermediate; wherein the fluorinated organic compound is selected from one or more of fluorescent anhydrides, fluorinated isocyanates, and fluorinated acyl halides; and

[0012] The end-capping intermediate was immersed in the electrolyte and swollen to obtain a gel quasi-solid electrolyte.

[0013] Optionally, in some embodiments of the present invention, the reaction temperature is 20–80°C and the reaction time is 30–120 min.

[0014] Optionally, in some embodiments of the present invention, the soaking time of the gel intermediate in fluorinated organic matter is 4–12 h; and / or

[0015] The immersion time of the end-capping intermediate in the electrolyte is 4 to 12 hours.

[0016] Optionally, in some embodiments of the present invention, before mixing the polyether polyol, isocyanate, catalyst and inorganic filler, the process further includes vacuum dehydration of the polyether polyol for 1.5 to 2.5 hours.

[0017] Optionally, in some embodiments of the present invention, the hydroxyl functionality of the polyether polyol is 2 to 6; and / or

[0018] The molecular weight of the polyether polyol is 400–20000; and / or

[0019] The hydroxyl value of polyether polyols is 10–400 mg KOH / g.

[0020] Optionally, in some embodiments of the present invention, the fluoroanhydride is selected from one or more of trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluorobutyric anhydride, nonafluorovalerate anhydride, perfluorohexanoic anhydride, perfluoroheptanoic anhydride, tetrafluorosuccinic anhydride, and trifluoromethanesulfonic anhydride; the fluorinated isocyanate is selected from one or more of 2-fluoro-5-trifluoromethylphenyl isocyanate, 4-trifluoromethylbenzyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate, and pentafluorophenyl isocyanate; and the fluorinated acyl halide is selected from one or more of 2-fluorobenzoyl chloride, 3-fluorobenzoyl chloride, tetrafluorobenzoyl chloride, pentafluorobenzoyl chloride, and ethylhexafluoroglutaryl chloride; and / or

[0021] Isocyanates are selected from one or more of diisocyanates and triisocyanates; and / or

[0022] The catalyst is selected from one or more of dibutyltin dilaurate, triethylamine, stannous octoate, and dimorpholine diethyl ether; and / or

[0023] The inorganic filler is selected from one or more of alumina, silicon dioxide, titanium dioxide, zinc oxide, and garnet.

[0024] Optionally, in some embodiments of the present invention, the molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of the isocyanate is 1:0.5-2; and / or

[0025] The sum of the masses of the polyether polyol and the isocyanate is the additive mass, and the mass of the catalyst is 0.5% to 2% of the additive mass; and / or

[0026] The total mass is the sum of the masses of polyether polyol, isocyanate, catalyst and inorganic filler, with the inorganic filler accounting for 5% to 80% of the total mass.

[0027] Optionally, in some embodiments of the present invention, the end-capping intermediate is immersed in the electrolyte multiple times, and the electrolyte is replaced between each two immersions.

[0028] In addition, the gel quasi-solid electrolyte is prepared by the above-described method for preparing gel quasi-solid electrolytes.

[0029] In addition, the lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is prepared by the above-described method for preparing a gel quasi-solid electrolyte, or the electrolyte is the above-described gel quasi-solid electrolyte.

[0030] Compared to existing technologies, this invention offers the following advantages: This method utilizes the crosslinking reaction of multifunctional, high-molecular-weight polyether polyols with isocyanates. Under conditions where an inorganic filler serves as the "quasi-solid" core and a catalyst is used for catalysis, the substances complement each other, reacting to generate a gel intermediate. In subsequent preparation, the prepared gel intermediate is immersed in a fluorinated organic compound. This operation effectively capsifies and passivates unreacted active groups on the gel intermediate structure, ensuring that the resulting gel quasi-solid electrolyte has the ability to withstand high voltages. The gel quasi-solid electrolyte obtained through this method exhibits advantages such as high ionic conductivity and good wettability at the electrode interface. Furthermore, the polyether segments within it have excellent affinity for the electrolyte, resulting in a high liquid absorption rate, reaching 300–1100% compared to existing technologies. Thus, it can be seen that, with the same amount of electrolyte, the amount of polymer matrix used in the gel quasi-solid electrolyte in this scheme is effectively reduced. When the gel quasi-solid electrolyte is applied to the battery, the energy density of the battery can be significantly improved, while safety and cycle performance can also be improved.

[0031] The preparation method of the gel quasi-solid electrolyte provided in this solution is simple to operate and convenient to prepare. It can produce gel quasi-solid electrolytes with high liquid absorption rate and good high voltage tolerance. The electrolyte has excellent overall performance. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the ionic conductivity performance of the gel quasi-solid electrolyte provided in Example 1 of the present invention;

[0034] Figure 2 This is a schematic diagram of the cycle performance of the lithium-ion battery provided in Embodiment 1 of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The technical solutions provided by this invention will be described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this invention, the term "comprising" means "including but not limited to". Various embodiments of this invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range.

[0037] An embodiment of the present invention provides a method for preparing a gel quasi-solid electrolyte, comprising:

[0038] A gel intermediate is obtained by mixing polyether polyol, isocyanate, catalyst and inorganic filler and reacting.

[0039] A gel intermediate is immersed in a fluorinated organic compound to obtain a capping intermediate; wherein the fluorinated organic compound is selected from one or more of fluorescent anhydrides, fluorinated isocyanates, and fluorinated acyl halides; and

[0040] The end-capping intermediate was immersed in the electrolyte and swollen to obtain a gel quasi-solid electrolyte.

[0041] The hydroxyl groups of polyether polyols and the isocyanate groups of isocyanates undergo a cross-linking reaction under the conditions of inorganic fillers and catalysts to generate a gel intermediate. The inorganic filler constructs a "quasi-solid-state" core, whose functions include: improving the mechanical properties of the resulting gel quasi-solid-state electrolyte; enhancing the safety of batteries using the gel quasi-solid-state electrolyte; and suppressing lithium dendrite formation, thereby improving the cycle stability of batteries using the gel quasi-solid-state electrolyte. Immersing the gel intermediate in a fluorinated organic solution can cap unreacted active groups on the gel intermediate structure, thus ensuring that the subsequently obtained gel quasi-solid-state electrolyte has the ability to withstand high voltages.

[0042] It should be noted that the term "fluorine-containing" as used above primarily indicates that the corresponding compound contains fluorine atoms. For example, "fluorine-containing anhydride" means an anhydride containing fluorine atoms.

[0043] After obtaining the gel intermediate through the reaction, it can be dried before immersing it in a fluorinated organic compound. Drying the obtained gel intermediate provides the necessary conditions for subsequent immersion in the fluorinated organic compound. Drying methods include vacuum drying, atmospheric pressure drying, and microwave drying, with vacuum drying being preferred. The drying temperature is 40–60°C, and the drying time is 2–6 hours.

[0044] It should be noted that the term "immersion" in fluorinated organic matter refers only to the intermediate being in a fluorinated organic environment and does not restrict the specific actions taken. That is, the intermediate can be placed directly in the fluorinated organic matter, or the fluorinated organic matter can be injected into the container containing the intermediate, thus achieving the goal of placing the intermediate in a fluorinated organic environment.

[0045] The gel intermediate can be immersed in a fluorinated organic compound under a protective gas environment, thus avoiding adverse effects from external conditions. The protective gas can be selected from one or more of nitrogen and inert gases (such as argon). When immersing the gel intermediate in the fluorinated organic compound, it can be immersed in a fluorinated organic compound with a catalyst added. This catalyst catalyzes the reaction between the unreacted active groups in the gel intermediate and the fluorinated organic compound. Furthermore, the catalyst can be selectively chosen based on the specific fluorinated organic compound. For example, when immersing a gel intermediate containing hydroxyl groups in a hydrofluoric anhydride, a pyridine catalyst can be selected; when immersing a gel intermediate containing hydroxyl groups in a fluorinated isocyanate, an organotin catalyst can be selected; and when immersing a gel intermediate containing hydroxyl groups in a fluorinated acyl halide, an organic base catalyst can be selected. When immersing the gel intermediate in the fluorinated organic compound with the added catalyst, the gel intermediate can be submerged in a mixture containing the catalyst and the fluorinated organic compound, or the mixture can be added to the container containing the gel intermediate.

[0046] It should also be noted that immersing the end-capping intermediate in the electrolyte means that the end-capping intermediate is in an electrolyte environment, and does not restrict the operation. That is, the fluorinated end-capping intermediate can be placed in the electrolyte, or the electrolyte can be injected into the container containing the end-capping intermediate, thereby achieving the purpose of placing the end-capping intermediate in an electrolyte environment.

[0047] In some embodiments, the reaction temperature for obtaining the gel intermediate is 20–80°C, and the reaction time is 30–120 min. Appropriate reaction temperature and time are beneficial to the reaction.

[0048] In some embodiments, the gel intermediate is soaked in fluorinated organic matter for 4–12 hours. Appropriate soaking time is beneficial for the formation of the capping intermediate.

[0049] In some embodiments, the immersion time of the end-capping intermediate in the electrolyte is 4–12 hours. Under this time condition, the end-capping intermediate can fully absorb and displace the electrolyte, and fully swell.

[0050] In some embodiments, before mixing the polyether polyol, isocyanate, catalyst, and inorganic filler, the process further includes vacuum dehydration of the polyether polyol for 1.5–2.5 h. Dehydration of the polyether polyol can improve the industrial battery performance of the resulting gel quasi-solid electrolyte when used in batteries. Considering the boiling point of water, vacuum dehydration is preferably carried out at a temperature above 100°C to obtain better dehydration results. More preferably, vacuum dehydration can be carried out at a temperature of 100–120°C.

[0051] In some embodiments, the hydroxyl functionality of the polyether polyol can be 2 to 6.

[0052] In some embodiments, the molecular weight of the polyether polyol can be 400 to 20,000.

[0053] In some embodiments, the hydroxyl value of the polyether polyol can be 10 to 400 mg KOH / g.

[0054] Polyether polyols that meet the above requirements are particularly suitable for preparing gel quasi-solid electrolytes.

[0055] In some embodiments, the fluoroanhydride is selected from one or more of trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluorobutyric anhydride, nonafluorovalerate anhydride, perfluorohexanoic anhydride, perfluoroheptanoic anhydride, tetrafluorosuccinic anhydride, and trifluoromethanesulfonic anhydride; the fluorinated isocyanate is selected from one or more of 2-fluoro-5-trifluoromethylphenyl isocyanate, 4-trifluoromethylbenzyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate, and pentafluorophenyl isocyanate; and the fluorinated acyl halide is selected from one or more of 2-fluorobenzoyl chloride, 3-fluorobenzoyl chloride, tetrafluorobenzoyl chloride, pentafluorobenzoyl chloride, and ethylhexafluoroglutaryl chloride.

[0056] In some embodiments, the isocyanate is selected from one or more of diisocyanates and triisocyanates. Specifically, the diisocyanate may be selected from one or more of hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polydiphenylmethane diisocyanate (PM200, PM400, etc.), and lysine diisocyanate (LDI); the triisocyanate may be selected from triphenylmethane triisocyanate.

[0057] In some embodiments, the catalyst used for mixing with inorganic fillers, etc., may be selected from one or more of dibutyltin dilaurate, triethylamine, stannous octoate, and dimorpholine diethyl ether.

[0058] In some embodiments, the inorganic filler may be selected from one or more of alumina, silica, titanium dioxide, zinc oxide, and garnet. The particle size of the inorganic filler may be 100–1000 nm.

[0059] In some embodiments, the molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of the isocyanate is 1:0.5 to 2. Since both the polyether polyol and the isocyanate can be selected from a variety of specific substances, the ratio of hydroxyl to isocyanate groups can be controlled. The preferred molar ratio of hydroxyl to isocyanate groups is 1:1. For example, if the hydroxyl functionality of the polyether polyol is 3 and the isocyanate group functionality of the isocyanate is 2, then the molar ratio of the polyether polyol to isocyanate is 2:3.

[0060] In some embodiments, the sum of the masses of the polyether polyol and the isocyanate is the additive mass, and the mass of the catalyst is 0.5% to 2% of the additive mass. At this dosage, the catalyst exhibits a good promoting effect.

[0061] In some embodiments, the sum of the masses of the polyether polyol, isocyanate, catalyst and inorganic filler is the total mass, and the mass of the inorganic filler is 5% to 80% of the total mass.

[0062] In some embodiments, after obtaining the gel intermediate and before immersing the gel intermediate in a fluorinated organic compound (or before the aforementioned drying), the method further includes: preparing the gel intermediate into a film with a thickness of 50–500 μm. The film can be prepared by a coating method: coating a film on a substrate such as glass or metal to form a film with a thickness of 50–500 μm.

[0063] In some embodiments, the solvent of the electrolyte used for soaking the end-capping intermediate may be selected from one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, fluoroethylene carbonate, methyl ethyl carbonate, propylene carbonate, vinylene carbonate, propylene sulfite, diethoxymethane, methyl difluoroacetate, ethyl difluoroacetate, and 1,3-dioxocyclopentane. The solute of the electrolyte may be selected from one or more of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, and lithium dioxoborate. Further, the concentration of the solute in the electrolyte may be 0.8–1.5 mol / L.

[0064] In some embodiments, the end-capping intermediate is immersed in the electrolyte multiple times, with the electrolyte being changed between each two immersions. In the case of multiple immersions, each immersion can last from 4 to 12 hours. Removing the end-capping intermediate after immersion, changing the electrolyte, and then immersing it again enhances the replacement of fluorinated organic compounds in the end-capping intermediate by the electrolyte, thereby removing excess fluorinated organic compounds.

[0065] An embodiment of the present invention also provides a gel quasi-solid electrolyte, which is prepared by the above-described method for preparing a gel quasi-solid electrolyte.

[0066] Furthermore, embodiments of the present invention also provide a lithium-ion battery, including a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is prepared by the above-described method for preparing a gel quasi-solid electrolyte, or the electrolyte is the above-described gel quasi-solid electrolyte.

[0067] The positive electrode material can be selected from, but is not limited to, lithium iron phosphate (LFP), ternary materials, lithium cobalt oxide, and lithium manganese oxide; the negative electrode material can be selected from, but is not limited to, graphite, silicon carbide, and lithium metal.

[0068] The structural connections between the positive electrode, the negative electrode, and the electrolyte, such as a gel quasi-solid electrolyte, are well-known in the art and will not be described further here. Similarly, other structures that lithium-ion batteries may include, such as separators, are also well-known in the art and will not be described further here.

[0069] Example 1

[0070] This embodiment provides a method for preparing a gel quasi-solid electrolyte, including:

[0071] At 25°C, dehydrated polyether polyol (molecular weight 3000), hexamethylene diisocyanate, and nano-silica were added to a sample vial and stirred at 800 rpm for 30 min. Then, dibutyltin dilaurate was added, and stirring was continued for 5 min to ensure uniform mixing. The reaction was allowed to proceed for 80 min to obtain a gel intermediate. The gel intermediate was then coated onto a glass substrate to obtain a film with a thickness of 200 μm. The film was then placed in a forced-air drying oven and heated at 60°C for 1 h to complete the drying process.

[0072] The membrane was immersed in a mixture of trifluoroacetic anhydride and DMAP for 6 hours in an argon-filled glove box to obtain a capped intermediate.

[0073] The end-capping intermediate was immersed in the electrolyte for 4 hours, then the electrolyte was changed and the intermediate was immersed for another 4 hours to form a gel quasi-solid electrolyte.

[0074] The polyether polyol was purchased from Dow Chemical Company, brand name VORANOL 3003LM POLYOL, with a hydroxyl functionality of 3, a molecular weight of 3000, and a hydroxyl value of 56 mg KOH / g. The nano-silica had a particle size of 500 nm.

[0075] Regarding the reaction system ratio: the molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of hexamethylene diisocyanate is 1:1; the amount of catalyst (dibutyltin dilaurate) is 1% of the combined mass of the polyether polyol and hexamethylene diisocyanate; and the amount of silica is 20% of the total mass (the sum of the masses of polyether polyol, hexamethylene diisocyanate, nano silica, and dibutyltin dilaurate).

[0076] This embodiment also provides a gel quasi-solid electrolyte prepared by the above method, the ionic conductivity of which can be found in [reference needed]. Figure 1 .

[0077] This embodiment also provides a lithium-ion battery, including a positive electrode of ternary material NCM811, a negative electrode of lithium metal, and the aforementioned gel quasi-solid electrolyte. The cycle performance (charge / discharge rate 0.1C) of this lithium-ion battery is described in [reference needed]. Figure 2 ,Depend on Figure 2 It can be seen that the gel quasi-solid electrolyte provided in this embodiment is relatively stable compared to the high-voltage ternary cathode and has excellent long-cycle performance.

[0078] Example 2

[0079] This embodiment provides a method for preparing a gel quasi-solid electrolyte. This method is based on Example 1, except that the polyether polyol material is replaced. The polyether polyol used in this embodiment was purchased from Dow Chemical Company, brand name VORANOL4701POLYOL, with a hydroxyl functionality of 3, a molecular weight of 5000, and a hydroxyl value of 34 mg KOH / g.

[0080] This embodiment also provides a gel quasi-solid electrolyte prepared by the above method.

[0081] Example 3

[0082] This embodiment provides a method for preparing a gel quasi-solid electrolyte. This method is based on Example 1, except that the polyether polyol material is replaced. The polyether polyol used in this embodiment was purchased from Dow Chemical Company, brand name VORANOLCP 6001POLYOL, with a hydroxyl functionality of 3, a molecular weight of 6000, and a hydroxyl value of 28 mg KOH / g.

[0083] This embodiment also provides a gel quasi-solid electrolyte prepared by the above method.

[0084] Example 4

[0085] This embodiment provides a method for preparing a gel quasi-solid electrolyte, including:

[0086] Polyether polyol, toluene diisocyanate, stannous octoate, and titanium dioxide were mixed and reacted at 70°C for 40 min to obtain a gel intermediate, which was then dried under vacuum at 40°C for 5.5 h; and

[0087] The dried gel intermediate was immersed in a mixture of 2-fluoro-5-trifluoromethylphenyl isocyanate and dimethyltin for 8 hours under argon atmosphere to obtain the capped intermediate;

[0088] The end-capping intermediate was immersed in the electrolyte for 10 hours to form a gel quasi-solid electrolyte.

[0089] Among them, the polyether polyol is polyvinyl alcohol, with a hydroxyl functionality of 2, a molecular weight of 8000, and a hydroxyl value of 14 mg KOH / g.

[0090] Regarding the reaction system ratio: the molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of the toluene diisocyanate is 1:1.7; the amount of catalyst (stannous octoate) is 2% of the combined mass of the polyether polyol and the toluene diisocyanate; and the amount of titanium dioxide is 60% of the total mass (the sum of the masses of the polyether polyol, the toluene diisocyanate, the titanium dioxide, and the stannous octoate).

[0091] Example 5

[0092] This embodiment provides a method for preparing a gel quasi-solid electrolyte, including:

[0093] Polyether polyol, diphenylmethane diisocyanate, triethylamine, and titanium dioxide were mixed and reacted at 20°C for 110 min to obtain a gel intermediate. The gel intermediate was then coated onto a metal plate to obtain a film with a thickness of 80 μm. The film was then dried under vacuum at 55°C for 3 h.

[0094] The dried gel intermediate was immersed in a mixture of tetrafluorobenzoyl chloride and diisopropylaminolithium for 6 hours under nitrogen atmosphere to obtain the capped intermediate.

[0095] The end-capping intermediate was immersed in the electrolyte for 5 hours, then the electrolyte was replaced and the immersion time was 4 hours. The electrolyte was replaced again and the immersion time was 4 hours to form a gel quasi-solid electrolyte.

[0096] The polyether polyol has a hydroxyl functionality of 4, a molecular weight of 3000, and a hydroxyl value of 18 mg KOH / g. This polyether polyol can be obtained by addition polymerization with ethylene oxide using pentaerythritol as an initiator.

[0097] Regarding the reaction system ratio: the molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of the diphenylmethane diisocyanate is 1:0.5; the amount of catalyst (triethylamine) is 0.7% of the combined mass of the polyether polyol and diphenylmethane diisocyanate; and the amount of titanium dioxide is 15% of the total mass (the sum of the masses of the polyether polyol, diphenylmethane diisocyanate, titanium dioxide, and triethylamine).

[0098] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a gel quasi-solid electrolyte, characterized in that, include: A gel intermediate is obtained by mixing polyether polyol, isocyanate, catalyst and inorganic filler and reacting. The gel intermediate is immersed in a fluorinated organic compound to obtain a capping intermediate; wherein the fluorinated organic compound is selected from one or more of fluorescent anhydrides, fluorinated isocyanates, and fluorinated acyl halides. as well as The end-capping intermediate was immersed in an electrolyte and swollen to obtain a gel quasi-solid electrolyte.

2. The method for preparing the gel quasi-solid electrolyte according to claim 1, characterized in that, The reaction is carried out at a temperature of 20–80°C for a time of 30–120 min.

3. The method for preparing a gel quasi-solid electrolyte according to claim 1, characterized in that, The gel intermediate is soaked in the fluorinated organic compound for 4–12 hours; and / or The immersion time of the end-capping intermediate in the electrolyte is 4 to 12 hours.

4. The method for preparing the gel quasi-solid electrolyte according to claim 1, characterized in that, Before mixing the polyether polyol, isocyanate, catalyst and inorganic filler, the process further includes vacuum dehydration of the polyether polyol for 1.5 to 2.5 hours.

5. The method for preparing a gel quasi-solid electrolyte according to claim 1, characterized in that, The hydroxyl functionality of the polyether polyol is 2-6; and / or The polyether polyol has a molecular weight of 400 to 20,000; and / or The hydroxyl value of the polyether polyol is 10-400 mg KOH / g.

6. The method for preparing a gel quasi-solid electrolyte according to claim 1, characterized in that, The fluorinated anhydride is selected from one or more of trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluorobutyric anhydride, nonafluorovalerate anhydride, perfluorohexanoic anhydride, perfluoroheptanoic anhydride, tetrafluorosuccinic anhydride, and trifluoromethanesulfonic anhydride; the fluorinated isocyanate is selected from one or more of 2-fluoro-5-trifluoromethylphenyl isocyanate, 4-trifluoromethylbenzyl isocyanate, 3-(trifluoromethyl)phenyl isocyanate, and pentafluorophenyl isocyanate; the fluorinated acyl halide is selected from one or more of 2-fluorobenzoyl chloride, 3-fluorobenzoyl chloride, tetrafluorobenzoyl chloride, pentafluorobenzoyl chloride, and ethylhexafluoroglutaryl chloride; and / or The isocyanate is selected from one or more of diisocyanates and triisocyanates; and / or The catalyst is selected from one or more of dibutyltin dilaurate, triethylamine, stannous octoate, and dimorpholine diethyl ether; and / or The inorganic filler is selected from one or more of alumina, silicon dioxide, titanium dioxide, zinc oxide, and garnet.

7. The method for preparing a gel quasi-solid electrolyte according to claim 1, characterized in that, The molar ratio of the hydroxyl groups of the polyether polyol to the isocyanate groups of the isocyanate is 1:0.5-2; and / or The sum of the masses of the polyether polyol and the isocyanate is the additive mass, and the mass of the catalyst is 0.5% to 2% of the additive mass; and / or The total mass is the sum of the masses of the polyether polyol, the isocyanate, the catalyst, and the inorganic filler, and the mass of the inorganic filler is 5-80% of the total mass.

8. The method for preparing a gel quasi-solid electrolyte according to claim 1, characterized in that, The end-capping intermediate is immersed in the electrolyte multiple times, and the electrolyte is replaced between each two immersions.

9. A gel quasi-solid electrolyte, characterized in that, It is prepared by the method for preparing gel quasi-solid electrolyte according to any one of claims 1 to 8.

10. A lithium-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is prepared by the preparation method of the gel quasi-solid electrolyte according to any one of claims 1 to 8, or the electrolyte is the gel quasi-solid electrolyte according to claim 9.

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