Gel Electrolyte Lithium-Ion Battery Containing Ionic Polymer and Preparation Method

Abstract

The present invention relates to the field of lithium-ion batteries, and particularly to a gel electrolyte lithium-ion battery containing an ionic polymer and a preparation method thereof. The gel electrolyte lithium-ion battery containing an ionic polymer according to the present invention includes a positive electrode, a negative electrode, a separator, and an electrolyte. Among them, at least one of the positive electrode, the negative electrode, or the separator contains an ionic polymer, and in the ionic polymer, M w / M a ≥2, where M w is the weight-average molecular weight of the ionic polymer, and M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein. The M a is 100-2000 g / mol. The gel electrolyte lithium-ion battery of the present invention can adopt the traditional production process, avoiding the problems of complex process, unstable electrolyte, and difficulty in wetting the electrodes caused by adding a gel polymer or its precursor to the electrolyte in the prior art, and can meet the requirements of high energy density batteries.

Description

Technical Field

[0001] The present invention relates to the field of lithium-ion batteries, and particularly to a gel electrolyte lithium-ion battery containing an ionic polymer and a preparation method thereof. Background Art

[0002] In lithium-ion batteries, replacing traditional liquid electrolytes with gel electrolytes has two advantages: one is to prevent the leakage of the electrolyte solution and reduce the volatilization of the electrolyte solvent, thereby improving safety performance; the other is to reduce the contact between the electrolyte solution and the surface of the active material, thereby inhibiting the decomposition of the electrolyte solution, improving the high-temperature performance of the battery, extending the battery life, and also being beneficial to improving safety performance.

[0003] There are two types of ways to use gel electrolytes in lithium-ion batteries: one is to add a partially crystalline polymer to the electrolyte precursor to form a viscous liquid and coat it on the electrode sheet, and then extract the low-boiling solvent in the electrolyte precursor so that the polymer and the electrolyte form a physically cross-linked gel. The representative polymer is the copolymer P(VDF-co-HFP) of vinylidene fluoride and hexafluoropropylene, and the commercial company is Sony; the other is to add a precursor containing a monomer or oligomer with multiple double-bond functional groups and an initiator to the electrolyte solution, then inject the electrolyte solution into a dry battery cell, and then initiate the polymerization of the double bonds by heating or ultraviolet light irradiation to convert the electrolyte solution into a chemically cross-linked gel, that is, the so-called in-situ curing method. The representative monomer or oligomer is various monomers or oligomers containing acrylate or methacrylate groups, and the representative commercial company is Samsung.

[0004] In the above technologies, the types of polymers that can be selected in the first type are very few, and the only successful example is the PVDF copolymer used by Sony. However, this technology has two major problems: one is that the process is complex and the cost is high; the other is that the gel electrolyte basically does not contain low-boiling solvents, resulting in low conductivity of the electrolyte, which limits the rate performance and low-temperature performance of the battery. The second type of technology has more types of monomers or oligomers that can be selected, but this technology also has two major problems: one is that the electrolyte solution is prone to gelation and can only be stored at low temperatures for a short time; the other is that the electrolyte solution containing monomers or oligomers has a high viscosity, resulting in difficulty for the electrolyte solution to fully infiltrate the pores in the electrode, which does not meet the requirements of high-energy-density batteries for low-porosity electrodes. Summary of the Invention

[0005] Problems to be Solved by the Invention: In the prior art, the production process of gel electrolyte lithium-ion batteries is complex, the electrolyte solution is unstable, it is difficult to fully infiltrate the electrode, and the preparation cost is high, which cannot meet the production requirements of high-energy-density batteries.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] The present invention provides a gel electrolyte lithium-ion battery comprising an ionic polymer, which includes a positive electrode, a negative electrode, a separator and an electrolyte. Among them, at least one of the positive electrode, the negative electrode or the separator contains an ionic polymer, and in the ionic polymer, M w / M a ≥2, where M w is the weight-average molecular weight of the ionic polymer, and M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and M a is 100 - 2000 g / mol.

[0008] Preferably, in the ionic polymer, M w / M a is 2 - 2000, preferably 2 - 1000, more preferably 2 - 500.

[0009] Preferably, M a is 100 - 1000 g / mol.

[0010] Preferably, at 25 - 60 °C, the swelling degree of the ionic polymer in the electrolyte is greater than 50%, preferably the swelling loss rate of the ionic polymer in the electrolyte < 5%, more preferably the swelling degree is 50 - 500%.

[0011] Preferably, the positive electrode includes a current collector and a positive electrode material coated on the current collector; preferably, the positive electrode material includes a positive electrode active material and an ionic polymer; more preferably, based on the total solid weight of the positive electrode material, the content of the ionic polymer is 1 - 10%;

[0012] and / or, the negative electrode includes a current collector and a negative electrode material coated on the current collector; preferably, the negative electrode material includes a negative electrode active material and an ionic polymer; more preferably, based on the total solid weight of the negative electrode material, the content of the ionic polymer is 1 - 10%;

[0013] and / or, the separator includes a polymer microporous layer and a separator coating material coated on the polymer microporous layer; preferably, the separator coating material includes inorganic particles and an ionic polymer; more preferably, based on the total solid weight of the separator coating material, the content of the ionic polymer is 1 - 80%.

[0014] Preferably, the anionic groups of the ionic polymer are selected from one or more of carboxylate, sulfonate, sulfate and phosphate; preferably, the cations of the ionic polymer are selected from one or more of lithium ion, sodium ion, magnesium ion, calcium ion, barium ion and aluminum ion.

[0015] Preferably, the ionic polymer is selected from one or more of the following polymers: polyethers containing at least 2 anionic groups, polyesters containing at least 2 anionic groups, polyolefins containing at least 2 anionic groups, polycarbonates containing at least 2 anionic groups, and polyamides containing at least 2 anionic groups.

[0016] Preferably, the ionic polymer is selected from one or more of the following polymers:

[0017]

[0018] Wherein, R1-R3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X1-X3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and at least one of X1-X3 is an ionic group, the ionic group includes anionic group and cation, and m and n are both integers from 1 to 5000;

[0019]

[0020] Wherein, R4-R6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X4-X6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and at least one of X4-X6 is an ionic group, the ionic group includes anionic group and cation, and m and n are both integers from 1 to 5000;

[0021]

[0022] Wherein, R7-R 11 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X7-X 10 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and at least one of X7-X 10 is an ionic group, the ionic group includes anionic group and cation, and n is an integer from 1 to 5000;

[0023]

[0024] Wherein, R 12 -R 17Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 11 -X 14 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X 11 -X 14 At least one is an ionic group, and the ionic group includes an anion group and a cation. l, m, and n are all integers from 1 to 5000;

[0025]

[0026] Among them, R 18 -R 20 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 15 -X 17 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X 15 -X 17 At least one is an ionic group, and the ionic group includes an anion group and a cation. m and n are all integers from 1 to 5000;

[0027]

[0028] Among them, R 21 -R 23 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 18 -X 20 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X 18 -X 20 At least one is an ionic group, and the ionic group includes an anion group and a cation. m and n are integers from 1 to 5000;

[0029]

[0030] Among them, R 24 -R 28 Each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 21 -X 25Each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group or an ionic group, and X 21 -X 25 At least one of them is an ionic group, and the ionic group includes an anionic group and a cation, and n is an integer from 1 to 5000.

[0031] Preferably, the polyolefin having at least two anionic groups on the polymer side chain is formed by copolymerizing an ethylenic monomer containing an ionic group and an ethylenic monomer without an ionic group, and the structural formula of the ethylenic monomer containing an ionic group is as follows:

[0032]

[0033] Wherein, R1, R2, and R3 are each independently selected from a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group or a halogen-containing substituted hydrocarbon group, R4 is selected from a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group or a halogen-containing substituted hydrocarbon group, and X is an ionic group, and the ionic group includes an anionic group and a cation.

[0034] Preferably, the ethylenic monomer without an ionic group includes one or more of styrene, methylstyrene, acrylonitrile, acrylate, methacrylate, acrylamide, N-substituted methylacrylamide, vinyl ether, N-vinylpyrrolidone, vinylpyridine, maleic anhydride, maleimide, vinylene carbonate or vinyl ethyl carbonate.

[0035] Preferably, the electrolyte includes an organic solvent and a lithium salt; preferably, the organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and methyl propyl carbonate; more preferably, the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide, and preferably lithium hexafluorophosphate.

[0036] Preferably, the electrolyte further includes one or more of an unsaturated cyclic carbonate, a fluorinated cyclic carbonate, a cyclic sultone and a cyclic sulfate; preferably, the unsaturated cyclic carbonate is selected from vinylene carbonate and / or vinyl ethyl carbonate, and / or the fluorinated cyclic carbonate is selected from at least one of fluorinated ethylene carbonate, trifluoromethyl ethylene carbonate or difluorinated ethylene carbonate, and / or the cyclic sultone is selected from at least one of 1,3-propane sultone, 1,4-butane sultone and allyl-1,3-sultone, and / or the cyclic sulfate is selected from at least one of ethylene sulfate, propylene sulfate, 4-methyl ethylene sulfate.

[0037] The present invention also provides a method for preparing the above gel electrolyte lithium ion battery, which comprises the following steps: forming an electrode core with a positive electrode, a negative electrode and a separator, placing the electrode core in a battery case, then injecting an electrolyte to obtain a semi-finished lithium ion battery, and subjecting the semi-finished lithium ion battery to formation and degassing, and then sealing the liquid injection port of the battery case to obtain the gel electrolyte lithium ion battery.

[0038] The present invention also provides a lithium ion battery electrode, which comprises a current collector and an electrode material coating coated on the current collector, wherein the electrode material coating contains an ionic polymer and an active substance, and in the ionic polymer, M w / M a ≥2, wherein, M w is the weight average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol; preferably, based on the total weight of the solid content of the electrode material, the addition amount of the ionic polymer is 1 - 10%; more preferably, the electrode is a positive electrode or a negative electrode.

[0039] The present invention also provides a lithium ion battery separator, which comprises a polymer multi-microporous layer and a separator coating material coated on the polymer multi-microporous layer, wherein the separator coating material comprises inorganic particles and an ionic polymer, and in the ionic polymer, M w / M a ≥2, wherein, M w is the weight average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol; preferably, based on the total weight of the solid content of the separator coating material, the dosage of the ionic polymer is 1 - 80%, and further preferably, the polymer multi-microporous layer is a polyolefin microporous membrane or a non-woven fabric.

[0040] Advantages of the present invention:

[0041] (1) The present invention adds an ionic polymer with M w / M a ≥2 to the positive electrode, negative electrode or separator. After contacting with the electrolyte, the ionic polymer can absorb the electrolyte and swell to form a gel electrolyte, which can follow the traditional production process, reduce the complexity of the preparation process, reduce the production equipment cost, and avoid the problems of complex process, unstable electrolyte and difficult wetting of the electrode caused by adding a gel polymer or its precursor to the electrolyte in the prior art, and can meet the requirements of high energy density batteries;

[0042] (2) The ionic polymer used in the present invention is a polymer containing two or more anionic groups, and the ratio of the mass of the ionic polymer to the number of moles of anionic groups therein is 100 - 2000 g / mol, so that the swelling degree of the ionic polymer in the electrolyte is controlled within a suitable range, thereby enabling the gel electrolyte to have good conductivity, fully exerting the effect of the gel electrolyte, and at the same time not causing the polymer to swell too much in the electrolyte or even dissolve and lose its function. Detailed Embodiment

[0043] To make the objectives, technical solutions, and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. The following described embodiments are some embodiments of the present invention, rather than all embodiments. Combining the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0044] To better understand the above technical solutions, the present invention is further described in detail below.

[0045] In the present invention, the ionic polymer is added to the positive electrode, negative electrode, or separator. After the ionic polymer contacts the electrolyte, it can absorb the electrolyte and swell to form a gel electrolyte, which can follow the traditional production process, avoiding the problems of complex process, unstable electrolyte, and difficulty in wetting the electrode caused by adding the gel polymer or its precursor to the electrolyte in the prior art. The ionic groups contained in the ionic polymer are beneficial to improving the ionic conductivity, helping to form physical cross-linking to form a gel, and being beneficial to making the gel electrolyte battery have a high energy density and excellent charge-discharge cycle performance on the basis of exerting the above-mentioned various beneficial effects of the gel electrolyte.

[0046] In a specific embodiment of the present invention, the present invention provides a gel electrolyte lithium-ion battery containing an ionic polymer, including a positive electrode, a negative electrode, a separator, and an electrolyte. Among them, at least one of the positive electrode, negative electrode, or separator contains the ionic polymer, and in the ionic polymer, M w / M a ≥2, where M w is the weight-average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol.

[0047] It can be understood that M w / M a ≥2 in the ionic polymer, indicating that the ionic polymer molecule structure contains at least 2 anionic groups on average.

[0048] In some preferred embodiments of the present invention, in the ionic polymer, M w / M a is 2 - 2000, preferably 2 - 1000, more preferably 2 - 500.

[0049] Regarding the above-mentioned ionic polymer, a physical cross-linked structure can be formed by the aggregation of ionic groups. By controlling the content of the anionic groups therein within the above-mentioned appropriate range, it not only ensures that the formed gel electrolyte has good ionic conductivity, but also does not lose its function due to excessive swelling or even dissolution of the gel electrolyte in the electrolyte solution. That is, when the ionic groups of the above-mentioned ionic polymer are excessive, the swelling degree may be too low to form a gel, and when they are too few, the swelling may be too large or even dissolve.

[0050] In some preferred embodiments of the present invention, the M a is 100 - 1000 g / mol.

[0051] When the ratio of the mass of the ionic polymer to the number of moles of the anionic groups (M a ) contained therein is less than 100 g / mol, the content of the ionic groups is too high, there are too many physical cross-linking points, and the swelling degree of the polymer in the electrolyte solution is very small, reducing the conductivity of the formed gel electrolyte; while when the ratio of the mass of the ionic polymer to the number of moles of the anionic groups contained therein is greater than 2000 g / mol, the content of the ionic groups is too low, and the polymer swells too much or even dissolves in the electrolyte solution and loses its function.

[0052] In some preferred embodiments of the present invention, at 25 - 60 °C, the swelling degree of the ionic polymer in the electrolyte solution is greater than 50%, preferably the swelling loss rate < 5%, more preferably the swelling degree is 50 - 500%, further preferably the swelling degree is 50% - 300%, and even more preferably the swelling degree is 100% - 200%. When the swelling degree is lower than 50%, the conductivity of the gel electrolyte formed by the polymer is very low, the internal resistance of the battery increases, thereby affecting the charge and discharge rate performance and low-temperature cycle performance of the battery; when the swelling degree is higher than 500%, the mechanical properties of the above-mentioned ionic polymer become poor, and it may even dissolve in the electrolyte solution and lose the function of the gel electrolyte.

[0053] It should be noted that the molecular weight of the ionic polymer described in the present invention is the absolute molecular weight of the ionic polymer measured by gel permeation chromatography - multi-angle laser light scattering (GPC - MALLS).

[0054] The ratio of the mass of the ionic polymer described in the present invention to the number of moles of the anionic groups contained therein (M a) The concentration of metal cations in the ionic polymer is tested by an inductively coupled plasma optical emission spectrometer (ICP-OES), and then the ratio of the mass of the ionic polymer to the number of moles of anionic groups therein (g / mol) is calculated by a formula.

[0055]

[0056] In the above formula, C i is the concentration of metal cations in the polymer tested by ICP-OES, with the unit of g / kg, M i is the relative atomic mass of the corresponding metal cation, n i is the valence state of the metal cation. For example, for Li + and Na + then n i is 1, for Mg 2+ and Ca 2+ then the corresponding n i is 2, for Al 3+ then the corresponding n i is 3.

[0057] The degree of swelling described in the present invention refers to the ratio of the mass difference of the ionic polymer before and after soaking in the electrolyte to the mass of the polymer before soaking. The specific test method is as follows: The ionic polymer is made into a circular film with a thickness of 30 μm and a size of 16 mm * 16 mm, the mass of the film is weighed, the film is soaked in 10 g of the electrolyte, sealed and stored at a certain temperature. The film is taken out every 8 h, the electrolyte on the surface is wiped off, the thickness and weight are measured, and then it is put back into the electrolyte, sealed and continued to be stored at this temperature until the thickness and mass of the film remain unchanged for three consecutive tests, then it is considered that the ionic polymer film reaches the swelling equilibrium state. The degree of swelling is calculated according to the following formula:

[0058]

[0059] In the above formula, m0 represents the mass of the ionic polymer film before soaking in the electrolyte, and m1 represents the mass of the ionic polymer film after reaching the swelling equilibrium after soaking in the electrolyte.

[0060] The swelling loss rate described in the present invention refers to the ratio of the mass loss caused by the dissolution of part of the polymer into the electrolyte during the swelling of the ionic polymer to the mass of the polymer before swelling. The specific test method is as follows: The ionic polymer is made into a circular thin film with a thickness of 30 μm and a size of 16 mm * 16 mm, and the mass of the film is weighed. The film is immersed in 10 g of the electrolyte, sealed and stored at 60 °C. The film is taken out every 8 h, the electrolyte on the surface is wiped off, the thickness and mass are measured, and then it is put back into the electrolyte, sealed and continued to be stored at 60 °C until the thickness and mass of the film remain unchanged for three consecutive tests. The electrolyte in the film is removed by soaking with the solvent dimethyl carbonate (DMC), and then it is placed in an oven to be completely dried, and the mass of the remaining film after drying is weighed. The swelling loss rate is calculated according to the following formula:

[0061]

[0062] In the above formula, m0 represents the mass of the ionic polymer film before soaking in the electrolyte, with the unit of g, and m2 represents the mass of the remaining ionic polymer film after soaking in the electrolyte and then washing and drying, with the unit of g.

[0063] In some preferred embodiments of the present invention, the ionic group includes anionic groups and cations. The anionic group is selected from one or more of carboxylate, sulfonate, sulfate, and phosphate groups; preferably, the cation of the ionic group is selected from one or more of lithium ion, sodium ion, magnesium ion, calcium ion, barium ion, and aluminum ion. Polymers containing carboxylate, sulfonate, sulfate, and phosphate groups are easy to prepare and are stable in air. In particular, the combination of carboxylate, sulfonate, sulfate, and phosphate anions with cations such as lithium ion is relatively tight and will not dissolve in the electrolyte, and can form physical cross-linking points together with the cations. The cation is one or more of lithium ion, sodium ion, magnesium ion, calcium ion, barium ion, and aluminum ion. When the cation is lithium ion (Li + ), the lithium ion can be partially dissociated in the electrolyte, which is beneficial to improving the lithium ion conductivity of the gel electrolyte; when the cation is Na + , although it does not contribute to the lithium ion conductivity, it will not have a negative impact on the performance of the lithium ion battery; when the cation is Mg 2+ and Ca 2+ and other divalent ions or Al 3+ and other trivalent ions, it can combine with 2 or 3 anions and is difficult to dissociate in the electrolyte, which is more beneficial to forming physical cross-linking points and will not have a negative impact on the performance of the lithium ion battery.

[0064] In some preferred embodiments of the present invention, the anionic group is connected to the end group or side chain of the ionic polymer, that is, the anionic group is connected to the ionic polymer chain through a chemical bond, so that the anionic group will not migrate in the electric field, which is beneficial to increasing the lithium ion transference number of the formed gel electrolyte.

[0065] The ionic polymer of the present invention is selected from one or more of polyethers, polyesters, polyolefins, polycarbonates or polyamides. It should be noted that polyethers, polyesters, polyolefins, polycarbonates or polyamides are mainly classified according to the different main chain structures. For example, the structural formula of polyethers includes but is not limited to Formula 1, the structural formula of polyesters includes but is not limited to Formula 2 or Formula 3, the structural formula of polyolefins includes but is not limited to Formula 4, the structural formula of polycarbonates includes but is not limited to Formula 5, and the structural formula of polyamides includes but is not limited to Formula 6 or Formula 7;

[0066]

[0067] Wherein, R1-R3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, and X1-X3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and at least one of X1-X3 is an ionic group. The ionic group includes an anionic group and a cation, and m and n are both integers from 1 to 5000;

[0068]

[0069] Wherein, R4-R6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, and X4-X6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and at least one of X4-X6 is an ionic group. The ionic group includes an anionic group and a cation, and m and n are both integers from 1 to 5000;

[0070]

[0071] Wherein, R7-R 11 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, and X7-X 10 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X7-X 10At least one is an ionic group, and the ionic group includes an anionic group and a cation, where n is an integer from 1 to 5000;

[0072]

[0073] Among them, R 12 -R 17 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, or a sulfur-containing substituted hydrocarbon group, and X 11 -X 14 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group, or an ionic group, and X 11 -X 14 at least one is an ionic group, and the ionic group includes an anionic group and a cation, and l, m, and n are all integers from 1 to 5000;

[0074]

[0075] Among them, R 18 -R 20 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, or a sulfur-containing substituted hydrocarbon group, and X 15 -X 17 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group, or an ionic group, and X 15 -X 17 at least one is an ionic group, and the ionic group includes an anionic group and a cation, and m and n are both integers from 1 to 5000;

[0076]

[0077] Among them, R 21 -R 23 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, or a sulfur-containing substituted hydrocarbon group, and X 18 -X 20 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group, or an ionic group, and X 18 -X 20 at least one is an ionic group, and the ionic group includes an anionic group and a cation, and m and n are both integers from 1 to 5000;

[0078]

[0079] Wherein, R 24 -R 28 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, or a sulfur-containing substituted hydrocarbon group, X 21 -X 25 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group, or an ionic group, and at least one of X 21 -X 25 is an ionic group, the ionic group including an anionic group and a cation, and n is an integer from 1 to 5000.

[0080] According to the present invention, an ionic polymer of a polyether, polyester, polycarbonate, or polyamide having two or more anions on the end group is usually synthesized by end group modification. The most typical synthesis route is to first synthesize a polyether with a hydroxyl or carboxyl end group, a polyester with a hydroxyl or carboxyl end group, a polycarbonate with a hydroxyl end group, or a polyamide with an amine or carboxyl end group, and then convert the above end groups into the desired ionic groups.

[0081] For example, the typical synthesis route of a polyether-based ionic polymer is divided into two steps:

[0082] The first step is to obtain a polyether polyol by ring-opening polymerization of an epoxy monomer initiated by a polyol. Representative polyols include ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, etc., and representative epoxy monomers include ethylene oxide, propylene oxide, 1,3-dioxolane, 1,4-dioxane, etc.

[0083] The second step is to replace the hydroxyl group of the polyether polyol with an ionic group. Typical reactions are as follows:

[0084] (1)

[0085] (2)

[0086] (3)

[0087] (4)

[0088] For another example, polyester-based ionic polymers are divided into two categories. The main chain of one category is obtained by ring-opening polymerization of a lactone monomer initiated by a polyol, and its typical synthesis route is also divided into two steps:

[0089] The first step is to obtain a polyester polyol by ring-opening polymerization of a lactone monomer initiated by a polyol. Representative polyols include ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, etc., and representative lactone monomers include lactide, δ-valerolactone, ε-caprolactone, etc.

[0090] The second step is to replace the hydroxyl groups of the polyester polyol with ionic groups, and the synthesis reaction is the same as the method described in the second step of the synthesis of polyether ionic polymers.

[0091] Another type of main chain is obtained by the polycondensation reaction of diacid monomers and diol monomers, and its synthesis route is divided into two steps:

[0092] The first step is to obtain a polyester polyol by the polycondensation reaction of diacid monomers and diol monomers. Representative diacids include succinic acid, adipic acid, etc., and representative diols include ethylene glycol, 1,3-propanediol, 1,6-hexanediol, etc.

[0093] The second step is to replace the hydroxyl groups of the polyester polyol with ionic groups, and the synthesis reaction is the same as the method described in the second step of the synthesis of polyether ionic polymers.

[0094] The synthesis route of polycarbonate ionic polymers is also divided into two steps:

[0095] The first step is to obtain a polycarbonate polyol by the ring-opening polymerization of cyclic carbonate monomers initiated by polyols. Representative polyols include ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, etc., and representative cyclic carbonate monomers include ethylene carbonate, propylene carbonate, etc.

[0096] The second step is to replace the hydroxyl groups of the polyester polyol with ionic groups, and the synthesis reaction is the same as the method described in the second step of the synthesis of polyether ionic polymers.

[0097] In addition, monomers containing ionic groups themselves can also be used for polymerization to obtain the required polymers containing ionic groups. Typical examples include the polycondensation reaction of a diacid containing an ionic group shown by the following formula with a diol or a diamine to obtain the corresponding polyester or polyamide containing an ionic group.

[0098] (1)

[0099] (2)

[0100] Here, R1 and R2 are each independently selected from alkylene, haloalkylene, or oxygen-containing substituted alkylene, nitrogen-containing substituted alkylene, phosphorus-containing substituted alkylene, or sulfur-containing substituted alkylene, X1 and X2 are ionic groups, including the above-mentioned anionic groups and cations, and n is an integer from 1 to 5000. The number of carbon atoms of the above-mentioned alkyl groups is not particularly limited as long as it can meet the application requirements of the present invention.

[0101] According to the present invention, the synthesis route of the polyolefin ionic polymer with two or more anions on the polymer side chain is to copolymerize the olefin monomer containing ionic groups and the olefin monomer without ionic groups under the action of an initiator. The structural formula of the olefin monomer containing ionic groups is shown as follows;

[0102]

[0103] Among them, R1, R2, and R3 are each independently selected from a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group, or a halogen-containing substituted hydrocarbon group. R4 is selected from a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group, or a halogen-containing substituted hydrocarbon group. X is an ionic group, including an anion group and a cation.

[0104] The olefin monomer without ionic groups includes one or more of styrene, methylstyrene, acrylonitrile, acrylate, methacrylate, acrylamide, N-substituted methylacrylamide, vinyl ether, N-vinylpyrrolidone, vinylpyridine, maleic anhydride, maleimide, vinylene carbonate, and vinyl ethylene carbonate.

[0105] According to the present invention, the ionic polymer includes, but is not limited to, one or more of the following polymers:

[0106]

[0107]

[0108] According to the present invention, the positive electrode includes, but is not limited to, one or more of polyester 1, polyester 2, polyolefin 2, polyolefin 3, polycarbonate 1, polycarbonate 2, and polyamide 1;

[0109] And / or, the negative electrode includes, but is not limited to, one or more of polyether 1, polyether 5, polyolefin 1, polyamide 2, and polyamide 3;

[0110] And / or, the separator includes, but is not limited to, one or more of polyether 2, polyether 3, polyether 6, polyolefin 1, and polyolefin 4;

[0111] According to the present invention, based on the total weight of the positive electrode material solids, the positive electrode material includes, but is not limited to, one or more of 0-2% of polyester 1, 0-1% of polyester 2, 0-3% of polyolefin 2, 0-3% of polyolefin 3, 0-10% of polycarbonate 1, 0-5% of polycarbonate 2, and 0-2.5% of polyamide 1;

[0112] And / or, based on the total weight of the negative electrode material solids, the negative electrode material includes, but is not limited to, one or more of 0-4% of polyether 1, 0-8% of polyether 5, 0-10% of polyolefin 1, 0-4% of polyamide 2, and 0-5% of polyamide 3;

[0113] And / or, based on the total weight of the separator coating material solids, the separator coating material includes, but is not limited to, one or more of 0-20% of polyether 2, 0-8% of polyether 3, 0-80% of polyether 6, 0-80% of polyolefin 4, and 0-60% of polyolefin 1. Preferably, the separator coating material contains one or more of 4-20% of polyether 2, 0-8% of polyether 3, 1-80% of polyether 6, 1-80% of polyolefin 4, and 0-60% of polyolefin 1.

[0114] In some preferred embodiments of the present invention, the electrolyte includes an organic solvent and a lithium salt; preferably, the organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and methyl propyl carbonate; preferably ethylene carbonate and / or ethyl methyl carbonate, and more preferably the volume ratio of ethylene carbonate to ethyl methyl carbonate is 2-4:6-8; further preferably, the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, and lithium bis(fluorosulfonyl)imide, preferably lithium hexafluorophosphate, and more preferably, based on the volume of the electrolyte, the concentration of lithium hexafluorophosphate is 1-2 mol / L.

[0115] In some preferred embodiments of the present invention, the electrolyte further includes one or more of an unsaturated cyclic carbonate, a fluorinated cyclic carbonate, a cyclic sultone, and a cyclic sulfate. Preferably, the unsaturated cyclic carbonate is selected from vinylene carbonate and / or ethyl vinyl carbonate, and / or the fluorinated cyclic carbonate is selected from at least one of fluorinated ethylene carbonate, trifluoromethyl ethylene carbonate, or difluorinated ethylene carbonate, and / or the cyclic sultone is selected from at least one of 1,3-propane sultone, 1,4-butane sultone, and allyl-1,3-sultone, and / or the cyclic sulfate is selected from ethylene sulfate and / or 4-methyl ethylene sulfate; more preferably, based on the weight of the electrolyte, the electrolyte includes 1-2% of vinylene carbonate and 0.5-1.5% of 1,3-propane sultone.

[0116] In some preferred embodiments of the present invention, the positive electrode comprises a current collector and a positive electrode material coated on the current collector. The current collector can be various current collectors well-known to those skilled in the art, such as aluminum foil, carbon-coated aluminum foil, aluminum-coated polymer film. The above positive electrode material comprises the above ionomer and a positive electrode active material. Based on the total weight of the solid content of the positive electrode material, the content of the ionomer is 1-10%. It can be understood that the above positive electrode material further comprises a positive electrode conductive agent and a binder. The above positive electrode active material includes, but is not limited to, one or more of lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4). The positive electrode conductive agent includes, but is not limited to, one or more of carbon black conductive agent, carbon nanotube (CNT), SP-Li, flake graphite, Ketjen black, VGCF, CNF. The binder includes, but is not limited to, one or more of polyvinylidene fluoride (PVDF), homopolymer of vinylidene fluoride (VF2) and polyvinylidene fluoride copolymer, copolymer of vinylidene fluoride (VF2) / hexafluoropropylene (HFP).

[0117] In some preferred embodiments of the present invention, the negative electrode comprises a current collector and a negative electrode material coated on the current collector. The current collector can be various current collectors well-known to those skilled in the art, such as copper foil, carbon-coated copper foil, copper-coated polymer film. The above negative electrode material comprises the above ionomer and a negative electrode active material. Based on the total weight of the solid content of the negative electrode material, the content of the ionomer is 1-10%. It can be understood that the above negative electrode material further comprises a negative electrode conductive agent and a binder. The above negative electrode active material includes, but is not limited to, artificial graphite (C) or mesophase carbon microspheres. The conductive agent includes, but is not limited to, one or more of carbon black conductive agent, carbon nanotube (CNT), SP-Li, conductive graphite, flake graphite, Ketjen black, VGCF, CNF. The above binder includes, but is not limited to, one or more of styrene-butadiene rubber latex (SBR), sodium carboxymethyl cellulose (CMC), polyacrylic acid polymers (PAA).

[0118] In some preferred embodiments of the present invention, the separator includes a polymer microporous layer and a separator coating material coated on the polymer microporous layer; the above-mentioned separator coating material includes the above-mentioned ionic polymer and inorganic particles; based on the total weight of the solid content of the separator coating material, the content of the ionic polymer is 1-80%. It can be understood that the above-mentioned separator coating material also includes a binder, and the binder includes but is not limited to one or more of polyvinylidene fluoride (PVDF), styrene-butadiene rubber latex (SBR), and sodium carboxymethyl cellulose (CMC); the inorganic particles include but are not limited to at least one of ceramic powder, alumina, boehmite, calcium carbonate, hydrotalcite, montmorillonite, spinel, titanium dioxide, silicon dioxide, zirconium dioxide, magnesium oxide, calcium oxide, beryllium oxide, magnesium hydroxide, calcium hydroxide, and silicon carbide.

[0119] It should be noted that the positive electrode material solid content, negative electrode material solid content, or separator coating material solid content used as the content basis above refers to the solid components in the positive electrode material, negative electrode material, or separator coating except for the solvent.

[0120] In some preferred embodiments of the present invention, the preparation method of the above-mentioned positive electrode includes coating the slurry obtained by mixing the above-mentioned positive electrode materials on the current collector, and then drying to obtain a lithium-ion battery positive electrode.

[0121] In some preferred embodiments of the present invention, the preparation method of the above-mentioned negative electrode includes coating the slurry obtained by mixing the above-mentioned negative electrode materials on the current collector, and then drying to obtain a lithium-ion battery negative electrode.

[0122] In some preferred embodiments of the present invention, the preparation method of the above-mentioned separator includes coating the slurry obtained by mixing the above-mentioned separator coating material on the polymer microporous layer, and then drying to obtain a lithium-ion battery separator.

[0123] The present invention also provides a lithium-ion battery electrode, which includes a current collector and an electrode material coated on the current collector, wherein the electrode material includes an ionic polymer, an active substance, a conductive agent, and a binder, and in the ionic polymer, M w / M a ≥2, where M w is the weight average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of the anionic groups contained therein, and the M a is 100-2000 g / mol. Preferably, based on the total weight of the solid content of the electrode material, the addition amount of the ionic polymer is 1-10%.

[0124] It should be understood that the electrode includes a positive electrode or a negative electrode. When the electrode is a positive electrode, the electrode material refers to the positive electrode material, and the active material refers to the positive electrode active material; when the electrode is a negative electrode, the electrode material refers to the negative electrode material, and the active material refers to the negative electrode active material.

[0125] The present invention also provides a separator for a lithium-ion battery, which includes a polymer microporous layer and a separator coating material coated on the polymer microporous layer, wherein the separator coating material includes an ionic polymer, inorganic particles, and a binder, and in the ionic polymer, M w / M a ≥2, where M w is the weight-average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol. Preferably, based on the total weight of the solids of the separator coating material, the addition amount of the ionic polymer is 1 - 80%.

[0126] The present invention also provides a method for preparing the above lithium-ion battery, which includes the following steps: forming a battery core with a positive electrode, a negative electrode, and a separator, placing it in a battery case, then injecting an electrolyte to obtain a semi-finished lithium-ion battery, forming and exhausting the semi-finished lithium-ion battery, and then sealing the liquid injection port of the battery case to obtain a lithium-ion battery, wherein at least one of the positive electrode, the negative electrode, or the separator contains the above ionic polymer.

[0127] The following further elaborates on this application in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate this application and not to limit the scope of this application.

[0128] The raw materials or reagents used in the present invention are all purchased from mainstream manufacturers in the market. Those without indicating the manufacturer or the concentration are all raw materials or reagents of analytical purity grade that can be obtained conventionally. As long as they can play the expected role, there is no special limitation. The instrument and equipment used in this embodiment are all purchased from major manufacturers in the market. As long as they can play the expected role, there is no special limitation. For those not indicating the specific technology or conditions in this embodiment, they are carried out according to the technology or conditions described in the literature in this field or according to the product specification.

[0129] Reagents: Oxalic acid, ethylene glycol, p-toluenesulfonic acid, LiOH, azobisisobutyronitrile, benzoyl peroxide, stannous octoate, acrylonitrile, methyl acrylate, vinylsulfonic acid, methacrylic acid, methoxypolyethylene glycol methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl methacrylate phosphate, 1,3-propane sultone, propylene carbonate monomer, N,N-dimethylformamide, polyethylene glycol PEG400, polyethylene glycol PEG2000, polyethylene glycol PEG400, Na2SO3, NaOH, pentaerythritol, caprolactone, sulfuric acid, thionyl chloride, sodium carboxymethyl cellulose, N-methylpyrrolidone, decaglycerol, triethylene glycol, methyl methacrylate, benzoyl peroxide, acrylamide, butyl acrylate, p-styrenesulfonic acid, chlorosulfonic acid, trimesic acid, hexamethylenediamine, pyromellitic acid, 2,4-diaminobenzenesulfonic acid, etc. are all from Shanghai Macklin Biochemical Co., Ltd;

[0130] LiNi 0.8 Co 0.1 Mn 0.1 O2 is from Hubei Rongbai Lithium Battery Materials Co., Ltd;

[0131] Conductive agent (Super Li), PVDF binder ( 5130) is from SOLVAY (SHANGHAI) Co., Ltd;

[0132] Artificial graphite is from Tianjin BETRAY New Energy Technology Co., Ltd;

[0133] Styrene-butadiene rubber latex (SBR) (solid content 50%), alumina powder, polyethylene porous film, lithium hexafluorophosphate, ethylene carbonate (EC), ethyl methyl carbonate (EMC), vinylene carbonate are from Shanghai Macklin Biochemical Co., Ltd.

[0134] Hereinafter, the present invention will be described more specifically by way of examples and comparative examples, but the technical scope of the present invention is not limited to these examples. It should be noted that all percentages, parts, and ratios used in the present invention are based on mass unless otherwise specified.

[0135] The preparation examples of various ionic polymers are described below.

[0136] Preparation Example 1 of Polyether

[0137] Add 760 g of decaglycerol (1 mol), 200 g of an aqueous LiOH solution (concentration 10 wt%), and 1000 g of water to a reaction kettle. Stir well and dissolve at room temperature. Then add 640 g of acrylonitrile (AN, 12 mol). The molar ratio of decaglycerol to AN is 1:12. React at 40 °C for 20 h, then raise the temperature to 90 °C and reflux for 9 h. A large amount of alkaline gas is generated and collected with an acidic aqueous solution. Then add the remaining 2680 g of the aqueous LiOH solution for neutralization. The total molar ratio of LiOH to AN added twice is 1:1. After the reaction, vacuum dry to obtain polyether 1 containing lithium carboxylate, with the structural formula as follows:

[0138]

[0139] Preparation Example 2 of Polyether

[0140] Add 1000 g of polyethylene glycol PEG2000 (0.5 mol), 1 g of Mg(OH)2, and 1500 g of water to a reaction kettle. Stir well and dissolve at room temperature. Then add 53 g of acrylonitrile (AN, 1 mol). The molar ratio of PEG2000 to AN is 1:2. React at 40 °C for 20 h, then raise the temperature to 90 °C and reflux for 9 h. A large amount of alkaline gas is generated and collected with an acidic aqueous solution. Then add magnesium carbonate (0.5 mol, 42 g) in an amount equimolar to PEG2000 for neutralization reaction, and dissolve while reacting. After the reaction, vacuum dry to obtain polyether 2 containing magnesium carboxylate groups, with the structural formula as follows:

[0141]

[0142] Preparation Example 3 of Polyether

[0143] Under the condition of 80 °C, slowly drop 23.8 g of thionyl chloride (0.2 mol) into 40 g of polyethylene glycol PEG400 (0.1 mol). The molar ratio of PEG400 to thionyl chloride is 1:2. A large amount of gas is generated. Lead the gas to a NaOH aqueous solution for neutralization. After reacting for 18 h, cool the reaction solution to room temperature and slowly drop it into 250 g of an aqueous Na2SO3 solution (10 wt%). The molar ratio of PEG400 to Na2SO3 is 1:2. After the dropping is completed, react at 65 °C for 5 h. Dissolve the product in acetonitrile, remove the unreacted inorganic salts, and vacuum dry. After drying, obtain polyether 3 containing sodium sulfonate groups, with the structural formula as follows:

[0144]

[0145] Preparation Example 4 of Polyether

[0146] Add 50 g of polyethylene glycol PEG(M n(5000, 0.01 mol) was dissolved in NMP solution. Then, 2.44 g of 1,3 - propane sultone PS (0.02 mol) was added to the NMP solution of polyethylene glycol. The molar ratio of PEG to PS was 1:2. The reaction was carried out at 40 °C for 24 h. Then, an equivalent amount of LiOH aqueous solution (10 wt%) to PS was added for neutralization. After removing the solvent NMP and water, and drying under vacuum, a polyether 4 containing lithium sulfonate groups was obtained. The structural formula is as follows:

[0147]

[0148] Preparation Example 5 of Polyether

[0149] 300 g of triethylene glycol (2 mol), 15 g of LiOH aqueous solution (10 wt%) and 500 g of water were added to a reaction kettle and stirred well to dissolve at room temperature. Then, 212 g of acrylonitrile (AN, 4 mol) was added. The molar ratio of triethylene glycol to AN was 1:2. The reaction was carried out at 40 °C for 20 h, then the temperature was raised to 90 °C and refluxed for 9 h. A large amount of alkaline gas was generated and collected with an acidic aqueous solution. Then, 945 g of LiOH aqueous solution was added for neutralization. After the reaction, it was dried under vacuum to obtain a polyether 5 containing lithium carboxylate groups. The structural formula is as follows:

[0150]

[0151] Preparation Example 6 of Polyether

[0152] Under nitrogen protection, 23.3 g of chlorosulfonic acid (0.2 mol) was added to the NMP solution of 60 g of dry polyethylene glycol PEG600 (0.1 mol). The molar ratio of PEG600 to chlorosulfonic acid was 1:2. The mixed solution was stirred and reacted at 100 °C, generating a large amount of gas. The gas was led to a NaOH aqueous solution for neutralization. After reacting for 18 h, the reaction solution was cooled to room temperature and slowly dropped into 48 g of LiOH aqueous solution (10 wt%). The molar ratio of PEG600 to LiOH was 1:2. After removing the solvent NMP and water, and drying under vacuum, a polyether 6 containing lithium sulfate groups was obtained. The structural formula is as follows:

[0153]

[0154] Preparation Example 1 of Polyester

[0155] Add 495 g of oxalic acid (5.5 mol) and 310 g of ethylene glycol (5 mol) to the reaction kettle. The molar ratio of oxalic acid to ethylene glycol is 1.1:1. Then add 3 g of p-toluenesulfonic acid as a catalyst, evacuate, react at 160 °C for 10 h. After stopping the reaction, add acetonitrile to dissolve, and then add an aqueous solution of LiOH to adjust the pH to 7.0. Evacuate and dry to obtain the final product, polyester 1 containing carboxylic lithium groups, with the structural formula as follows:

[0156]

[0157] Preparation Example 2 of Polyester

[0158] Add 13.6 g of dried pentaerythritol (0.1 mol) and 183 g of caprolactone monomer (1.6 mol) to the reaction kettle. Then add 150 g of the solvent N,N-dimethylformamide (DMF) and 0.6 g of the catalyst sulfuric acid, and react at 110 °C for 24 h. After stopping the reaction, carry out a sulfonation reaction. At 80 °C, slowly dropwise add 48 g of thionyl chloride (0.4 mol) to the polymer solution, generating a large amount of gas. Lead the gas to an aqueous solution of NaOH for neutralization. After reacting for 18 h, cool the reaction solution to room temperature, and dropwise add it to 504 g of an aqueous solution of Na2SO3 (10 wt%). After the addition is completed, react at 65 °C for 5 h, remove the unreacted inorganic salts, evacuate and dry. The final product obtained after drying is star-shaped polyester 2 containing sodium sulfonate groups, with the structural formula as follows:

[0159]

[0160] Preparation Example 1 of Polyolefin

[0161] Add 16.4 g of azobisisobutyronitrile (AIBN, 0.1 mol), 1500 g of methoxypolyethylene glycol methacrylate (MPEGMA300, 5 mol), and 311 g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS, 1.5 mol) to the reaction kettle. The molar ratio of AIBN, MPEGMA300 to AMPS is 1:50:15. Then add 1.5 kg of N-methylpyrrolidone (NMP) as a solvent, and react at 70 °C under nitrogen protection for 10 h. Stop the reaction, add an aqueous solution of LiOH until the pH is adjusted to 7.0, evacuate and dry to obtain polyolefin 1 containing lithium sulfonate groups, with the structural formula as follows:

[0162]

[0163] Preparation Example 2 of Polyolefin

[0164] 32.8 g of azobisisobutyronitrile (AIBN, 0.2 mol), 636 g of acrylonitrile (AN, 12 mol), 400 g of methyl methacrylate (MMA, 4 mol) and 344 g of methacrylic acid (MAA, 4 mol) were added to a reaction kettle. The molar ratio of AIBN, AN, MMA and MAA was 1:60:20:20. Then 1.2 kg of N-methylpyrrolidone (NMP) was added as a solvent, and the reaction was carried out at 70 °C under nitrogen protection for 10 h. The reaction was stopped, and an aqueous LiOH solution was added until the pH was adjusted to 7.0. Vacuum drying was carried out to obtain polyolefin 2 containing lithium carboxylate groups, and the structural formula was as follows:

[0165]

[0166] Preparation Example 3 of Polyolefin

[0167] 2.42 g of benzoyl peroxide (BPO, 0.01 mol), 852 g of acrylamide (AM, 12 mol), 2304 g of butyl acrylate (BA, 18 mol) and 1830 g of styrene sulfonic acid (SSA, 10 mol) were added to a reaction kettle. The molar ratio of BPO, AN, BA and SSA was 1:1200:1800:1000. Then 4 kg of N-methylpyrrolidone (NMP) was added as a solvent, and the reaction was carried out at 80 °C under nitrogen protection for 10 h. The reaction was stopped, and an aqueous LiOH solution was added until the pH was adjusted to 7.0. Vacuum drying was carried out to obtain polyolefin 3 containing lithium sulfonate groups, and the structural formula was as follows:

[0168]

[0169] Preparation Example 4 of Polyolefin

[0170] 4.84 g of benzoyl peroxide (BPO, 0.02 mol), 198 g of methyl acrylate (MA, 2.3 mol), 173 g of vinyl sulfonic acid (SVA, 1.6 mol) and 22.8 g of 2-hydroxyethyl methacrylate phosphate (HEMAP, 0.1 mol) were added to a reaction kettle. The molar ratio of BPO, MA, SVA and HEMAP was 1:115:80:5. Then 600 g of N-methylpyrrolidone (NMP) was added as a solvent, and the reaction was carried out at 80 °C under nitrogen protection for 10 h. The reaction was stopped, and an aqueous LiOH solution was added until the pH was adjusted to 7.0. Vacuum drying was carried out to obtain polyolefin 4 containing lithium sulfonate groups, and the structural formula was as follows:

[0171]

[0172] Preparation Example 1 of Polycarbonate

[0173] 6.2 g of dried ethylene glycol (0.1 mol) and 204 g of propylene carbonate monomer (2 mol) were added to a reaction kettle. The molar ratio of ethylene glycol to propylene carbonate was 1:20. Then, 100 g of solvent N,N-dimethylformamide (DMF) and 0.5 g of catalyst stannous octoate were added. The reaction was carried out at 90 °C under nitrogen protection for 12 h. After the reaction was stopped and cooled to 0 °C, 23.3 g of chlorosulfonic acid HSO₃Cl (0.2 mol) was added. The molar ratio of chlorosulfonic acid to ethylene glycol was 2:1. After reacting overnight, an appropriate amount of aqueous LiOH solution was added until the pH was adjusted to 7.0, and then vacuum drying was carried out to obtain polycarbonate 1 containing lithium sulfate groups, and the structural formula is as follows:

[0174]

[0175] Preparation Example 2 of Polycarbonate

[0176] 31 g of dried ethylene glycol (0.5 mol) and 264 g of ethylene carbonate monomer (3 mol) were added to a reaction kettle. The molar ratio of ethylene glycol to ethylene carbonate was 1:6. Then, 130 g of solvent N,N-dimethylformamide (DMF) and 7.5 g of catalyst stannous octoate were added. The reaction was carried out at 90 °C under nitrogen protection for 12 h. After the reaction was stopped and cooled to 0 °C, 116.5 g of chlorosulfonic acid HSO₃Cl (1 mol) was added. The molar ratio of chlorosulfonic acid to ethylene glycol was 2:1. After reacting overnight, an appropriate amount of aqueous LiOH solution was added until the pH was adjusted to 7.0, and then vacuum drying was carried out to obtain polycarbonate 2 containing lithium sulfate groups, and the structural formula is as follows:

[0177]

[0178] Preparation Example 1 of Polyamide

[0179] 212.2 g of dried trimesic acid (1.01 mol) and 116.2 g of hexamethylenediamine (1 mol) were added to a reaction kettle. The molar ratio of trimesic acid to hexamethylenediamine was 1.01:1. The reaction was carried out under vacuum at 250 °C for 12 h. After the reaction was stopped, water was added for dissolution, and at the same time, an aqueous LiOH solution was added until the pH was adjusted to 7.0, and then vacuum drying was carried out. The final product obtained after drying was polyamide 1 containing carboxyl lithium groups, and the structural formula is as follows:

[0180]

[0181] Preparation Example 2 of Polyamide

[0182] 513.4 g of dried pyromellitic acid (2.02 mol) and 120 g of ethylenediamine (2 mol) were added to a reaction kettle. The molar ratio of pyromellitic acid to ethylenediamine was 1.01:1. The reaction was carried out under vacuum at 250 °C for 12 h. After the reaction was stopped, water was added for dissolution, and at the same time, an aqueous LiOH solution was added until the pH was adjusted to 7.0. Then, vacuum drying was carried out. The final product obtained after drying was polyamide 2 containing carboxyl lithium groups, and the structural formula was as follows:

[0183]

[0184] Preparation Example 3 of Polyamide

[0185] 295.2 g of dried adipic acid (2.02 mol) and 376.4 g of 2,4-diaminobenzenesulfonic acid (2 mol) were added to a reaction kettle. The molar ratio of adipic acid to 2,4-diaminobenzenesulfonic acid was 1.01:1. The reaction was carried out under vacuum at 250 °C for 12 h. After the reaction was stopped, water was added for dissolution, and at the same time, an aqueous LiOH solution was added until the pH was adjusted to 7.0. Then, vacuum drying was carried out. The final product obtained after drying was polyamide 3 containing lithium sulfonate and carboxyl lithium groups, and the structural formula was as follows:

[0186]

[0187] The following method was used to test the performance of the ionic polymer, and the measurement results are shown in Table 1.

[0188] (1) Determination of the molecular weight of the ionic polymer:

[0189] The absolute molecular weight of the ionic polymer was determined by gel permeation chromatography - laser light scattering coupling method (GPC - MALLS). The gel chromatography instrument was a 1515 GPC gel chromatography instrument from Waters Corporation, USA, and the light scattering detector was a DAWN HELEOS - II light scattering detector from Wyatt Corporation, USA.

[0190] (2) Determination of the ratio (M a ) of the mass of the ionic polymer to the number of moles of anionic groups contained therein:

[0191] First, the concentration of metal cations in the ionic polymer, such as Li + , Na + , Mg 2+ , Al 3+Etc., and the specific test method is as follows: Accurately weigh 1.0 g of the sample with a 50 mL PTFE beaker, add 3 mL of concentrated nitric acid + 9 mL of hydrochloric acid, heat in a graphite digestion furnace at 150 °C for 30 min, filter and transfer to a 100 mL volumetric flask for volume fixation, and then test with ICP-OES. The model of the ICP-OES instrument used is PQ9000 of Analytik Jena AG, Germany.

[0192] Then, calculate the ratio (g / mol) M of the mass of the ionic polymer to the number of moles of anionic groups therein through the formula. a

[0193]

[0194] In the above formula, C i is the concentration of metal cations in the polymer measured by ICP-OES, with the unit of g / kg, M i is the relative atomic mass of the corresponding metal cation, n i is the valence state of the metal cation. For example, for Li + and Na + then n i is 1, for Mg 2+ and Ca 2+ then the corresponding n i is 2, and for Al 3+ then the corresponding n i is 3.

[0195] (3) Determination of the degree of swelling:

[0196] Prepare the ionic polymer into a circular film with a thickness of 30 μm and a size of 16 mm * 16 mm, weigh the mass of the film, immerse the film in 10 g of electrolyte solution, seal it and store it at 60 °C. Take out the film every 8 h, wipe off the electrolyte solution on the surface, measure the thickness and weigh it, then put it back into the electrolyte solution, seal it and continue to store it at 60 °C until the thickness and mass of the film remain unchanged for three consecutive tests, then it is considered that the ionic polymer film reaches the swelling equilibrium state. Calculate the degree of swelling according to the following formula: The mass difference before and after immersing in the electrolyte solution / the mass of the film before immersion * 100% is the degree of swelling of the polymer.

[0197]

[0198] In the above formula, m0 represents the mass of the ionic polymer film before immersing in the electrolyte solution, and m1 represents the mass of the ionic polymer film after reaching the swelling equilibrium after immersing in the electrolyte solution.

[0199] Among them, the electrolyte is prepared as follows: Lithium hexafluorophosphate (LiPF6) is dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC is 3:7) in a glove box with a dew point lower than -40°C to prepare an electrolyte with a concentration of LiPF6 of 1.2 mol / L. Then, vinylene carbonate (VC) accounting for 1.5% of the total weight of the electrolyte and 1,3 - propane sultone (1,3 - PS) are added to obtain the required electrolyte.

[0200] (4) Measurement of swelling loss rate

[0201] The ionic polymer is made into a circular film with a thickness of 30 μm and a size of 16 mm * 16 mm. The mass of the film is weighed. The film is immersed in 10 g of electrolyte, sealed and stored at 60°C. The film is taken out every 8 h, the electrolyte on the surface is wiped off, the thickness is measured and weighed, and then it is put back into the electrolyte, sealed and continued to be stored at 60°C until the thickness and mass of the film remain unchanged for three consecutive tests. The excess electrolyte and lithium salt on the film are rinsed off with the solvent dimethyl carbonate (DMC), completely dried in an oven, and the mass of the remaining film after drying is weighed. The swelling loss rate is calculated according to the following formula:

[0202]

[0203] In the above formula, m0 represents the mass of the ionic polymer film before immersing in the electrolyte, with the unit of g, and m2 represents the mass of the remaining ionic polymer film after washing and drying after immersing in the electrolyte, with the unit of g.

[0204] Among them, the electrolyte is prepared as follows: Lithium hexafluorophosphate (LiPF6) is dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC is 3:7) in a glove box with a dew point lower than -40°C to prepare an electrolyte with a concentration of LiPF6 of 1.2 mol / L. Then, vinylene carbonate (VC) accounting for 1.5% of the total weight of the electrolyte and 1,3 - propane sultone (1,3 - PS) are added to obtain the required electrolyte.

[0205] Example 1

[0206] 1. Battery fabrication

[0207] 1.1 Preparation of the positive electrode plate

[0208] The positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, carbon black conductive agent (Super Li), PVDF binder ( 5130) Mix and input into a double planetary mixer in a weight ratio of 96.5:1.5:2. The total weight of the positive electrode active material, carbon black conductive agent, and binder is 1 kg. Add 0.5 kg of N-methylpyrrolidone (NMP). After fully stirring evenly, add polyester 1 accounting for 2% of the total weight of the positive electrode material solids. Continue to stir evenly and then filter through a filter screen to obtain the positive electrode material slurry, and the solid content of the slurry is 65%. Then use an extrusion coater to coat the slurry on both sides of an aluminum foil with a thickness of 12 μm. After baking and hot roll pressing, a positive electrode plate is obtained, and the areal density of the single-sided coating of the positive electrode plate is 20 mg / cm 2 , and the thickness of the single-sided coating is 58 μm.

[0209] 12 Preparation of negative electrode plate

[0210] Mix artificial graphite as the negative electrode active material, carbon black conductive agent (Super Li), and sodium carboxymethyl cellulose (CMC) in a weight ratio of 97:1.5:1.5 and input them into a double planetary mixer. The total weight of the negative electrode active material, carbon black conductive agent, and sodium carboxymethyl cellulose is 1 kg. Add 0.8 kg of deionized water (DIW). After fully stirring evenly, add styrene-butadiene rubber latex (SBR) with a solid content of 50% accounting for 1% of the total weight of the negative electrode material solids and polyether 1 accounting for 4% of the total weight of the negative electrode material solids. Continue to stir evenly and then filter through a filter screen to obtain the negative electrode material slurry, and the solid content of the slurry is 45%. Then use an extrusion coater to coat the slurry on both sides of a copper foil with a thickness of 6 μm. After baking and hot roll pressing, a negative electrode plate is obtained, and the areal density of the single-sided coating of the negative electrode plate is 13 mg / cm 2 , and the thickness of the single-sided coating is 79 μm.

[0211] 1.3 Preparation of separator

[0212] Mix alumina powder (D50 is 1.5 μm) and sodium carboxymethyl cellulose (CMC) in a weight ratio of 99.25:0.75 and input them into 1.5 kg of deionized water (DIW). The total weight of the alumina powder and sodium carboxymethyl cellulose (CMC) is 1 kg. Stir and grind in a stirring grinder until the particle size of the alumina is below 2 μm, then transfer it to a stirring tank, and then add styrene-butadiene rubber latex (SBR) with a solid content of 50% accounting for 1.2% of the total weight of the separator coating material solids and polyether 2 accounting for 4% of the total weight of the separator coating material solids. After stirring evenly, filter through a filter screen to obtain the separator coating material slurry, and the solid content of the slurry is 10%. Then coat the slurry on one surface of a polyethylene porous film with a thickness of 9 μm (porosity 45%) by gravure printing. Repeat this step to coat the slurry on the other surface of the polyethylene porous film. After drying, a composite porous separator with a single-sided inorganic coating thickness of 3 μm is obtained. The total thickness of the composite porous separator is 15 μm.

[0213] 1.4 Preparation of Dry Electrochemical Cell

[0214] Cut the above-mentioned positive electrode plate, negative electrode plate, and separator into certain shapes. The size of the active material area on the positive electrode plate is 48 mm × 44 mm, the size of the active material area on the negative electrode plate is 52 mm × 46 mm, and the size of the separator is 56 mm × 50 mm. Moreover, current collector lead-out parts are left on the positive electrode plate and the negative electrode plate respectively. Then stack them layer by layer in the order of negative electrode plate, separator, positive electrode plate, separator, negative electrode plate, … There are a total of 18 positive electrode plates and 19 negative electrode plates, and the outermost layer is the negative electrode plate. Then weld the current collector lead-out parts of the positive electrode plates together with an ultrasonic welder and weld on the positive electrode tab. Weld the current collector lead-out parts of the negative electrode plates together with an ultrasonic welder and weld on the negative electrode tab. In this way, a stacked body is obtained.

[0215] Put the above-mentioned stacked body into a packaging bag made of two aluminum-plastic films after shell punching, and fuse the hot melt adhesive on the electrode tabs with the packaging bag by hot melting. The electrode tabs are led out of the packaging bag, and an airbag and a liquid injection port are left on one side of the packaging bag. In this way, a dry electrochemical cell is obtained.

[0216] 1.5 Preparation of Electrolyte

[0217] Dissolve lithium hexafluorophosphate (LiPF6) in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC is 3:7) in a glove box with a dew point lower than -40°C to prepare an electrolyte with a concentration of LiPF6 of 1.2 mol / L. Then add vinylene carbonate (VC) accounting for 1.5% of the total weight of the electrolyte and 1,3-propane sultone (1,3-PS) of 1% to obtain the required electrolyte.

[0218] 1.6 Preparation of Battery

[0219] Inject the above-mentioned electrolyte into the dry electrochemical cell from the liquid injection port in a glove box with a dew point lower than -40°C. After standing for 24 hours, seal the liquid injection port outside the airbag with a vacuum heat sealer, and at the same time pump out the gas in the electrochemical cell. In this way, an unformed electrochemical cell is obtained. Weigh the weight of the unformed electrochemical cell, and subtract the weight of the dry electrochemical cell to obtain the weight of the injected electrolyte.

[0220] 1.7 Formation of Battery

[0221] Form the electrochemical cell with a charge-discharge device. First, charge it at a constant current of 0.05C to 3.6V, then use a vacuum heat sealer to evacuate, exhaust, seal, and cut off the airbag. Then charge it at a constant current of 0.2C to 4.2V, then charge it at a constant voltage until the current drops to 0.05C, and then discharge it at a constant current of 0.2C to 3.0V. In this way, a well-formed electrochemical cell is obtained, which is the gel electrolyte lithium-ion battery of the present invention.

[0222] 2. Testing of the battery

[0223] 2.1 Testing of the initial discharge capacity

[0224] At room temperature, the formed battery is charged at a constant current of 1C to 4.2V, then charged at a constant voltage until the current drops to 0.05C, and then discharged at a constant current of 1C to 3.0V to obtain the initial discharge capacity (Ah). Then, some of the batteries are subjected to high-temperature storage testing, and the other part of the batteries are subjected to charge-discharge cycle testing.

[0225] 2.2 High-temperature storage testing

[0226] At room temperature, the battery is charged at a constant current of 1C to 4.2V, then charged at a constant voltage until the current drops to 0.05C, and then the battery is transferred to an oven at 60°C for 7 days. After taking out the battery, measure the thickness of the battery and calculate the thickness expansion rate compared with the thickness before high-temperature storage, that is, thickness expansion rate = (battery thickness after high-temperature storage - battery thickness before high-temperature storage) / battery thickness before high-temperature storage * 100%;

[0227] After the battery is cooled to room temperature, it is discharged at a constant current of 1C to 3.0V, and the capacity retention rate is calculated by comparing the obtained discharge capacity with the discharge capacity before high-temperature storage, that is, capacity retention rate = discharge capacity after high-temperature storage / discharge capacity before high-temperature storage * 100%;

[0228] Then, the battery is charged at a constant current of 1C to 4.2V, then charged at a constant voltage until the current drops to 0.05C, and then discharged at a constant current of 1C to 3.0V again. The capacity recovery rate is calculated by comparing the obtained discharge capacity with the discharge capacity before high-temperature storage, that is, capacity recovery rate = discharge capacity after recharging and discharging after high-temperature storage / discharge capacity before high-temperature storage * 100%.

[0229] 2.3 Charge-discharge cycle testing

[0230] At room temperature, the battery is charged at a constant current of 1C to 4.2V, then charged at a constant voltage until the current drops to 0.05C, and then discharged at a constant current of 1C to 3.0V. Such a cycle is repeated 1000 times, and the discharge capacity retention rate is calculated by comparing the last discharge capacity with the first discharge capacity.

[0231] 2.4 Penetration test

[0232] Refer to GB / T 31485-2015 for the testing of the battery penetration safety. A steel needle with a diameter of 8mm penetrates the battery along the direction perpendicular to the electrode plate at a speed of 25mm / s and stays in it, and observe for 1h.

[0233] The above test results are shown in Table 2.

[0234] Example 2

[0235] Except that 3% of polyolefin 2 is added during the production process of the positive electrode plate, 5% of polyether 5 is added during the production process of the negative electrode plate, and 8% of polyether 3 is added during the production process of the separator, the rest is the same as in Example 1.

[0236] Test is carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0237] Example 3

[0238] Except that 2.5% of polyamide 1 is added during the production process of the positive electrode plate, 4% of polyamide 2 is added during the production process of the negative electrode plate, and 50% of polyolefin 1 is added during the production process of the separator, the rest is the same as in Example 1.

[0239] Test is carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0240] Example 4

[0241] Except that 1% of polyester 2 is added during the production process of the positive electrode plate, 1% of polyolefin 1 is added during the production process of the negative electrode plate, and 1% of polyether 6 is added during the production process of the separator, the rest is the same as in Example 1.

[0242] Test is carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0243] Example 5

[0244] Except that 10% of polycarbonate 1 is added during the production process of the positive electrode plate, 10% of polyolefin 1 is added during the production process of the negative electrode plate, and 80% of polyolefin 4 is added during the production process of the separator, the rest is the same as in Example 1.

[0245] Test is carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0246] Example 6

[0247] Except that 3% of polyolefin 3 is added during the production process of the positive electrode plate, 5% of polyamide 3 is added during the production process of the negative electrode plate, and no ionic polymer is added during the production process of the separator, the rest is the same as in Example 1.

[0248] Test is carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0249] Example 7

[0250] Except that 5% of polycarbonate 2 is added during the production process of the positive electrode plate, and no ionic polymer is added during the production processes of the negative electrode plate and the separator, the rest is the same as in Example 1.

[0251] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0252] Example 8

[0253] Except that 8% of polyether 5 is added during the production process of the negative electrode plate, 20% of polyether 2 is added during the production process of the separator, and no ionic polymer is added during the production process of the negative electrode plate, the rest is the same as in Example 1.

[0254] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0255] Example 9

[0256] Except that 5% of polyamide 2 is added during the production process of the negative electrode plate, and no ionic polymer is added during the production processes of the positive electrode plate and the separator, the rest is the same as in Example 1.

[0257] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0258] Example 10

[0259] Except that 60% of polyolefin 1 is added during the production process of the separator, and no ionic polymer is added during the production processes of the positive electrode plate and the negative electrode plate, the rest is the same as in Example 1.

[0260] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0261] Comparative Example 1

[0262] Except that no ionic polymer is added during the preparation processes of the positive electrode plate, the negative electrode plate and the separator, the rest is the same as in Example 1.

[0263] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0264] Comparative Example 2

[0265] Except that 5% of polyether 4 is added during the production process of the negative electrode plate, and no ionic polymer is added during the production processes of the positive electrode plate and the separator, the rest is the same as in Example 1.

[0266] The battery was tested according to the testing method of the battery in Example 1, and the test results are shown in Table 2.

[0267] Comparative Example 3

[0268] Except that 0.5% of polycarbonate 2 is added during the production process of the positive electrode plate, 0.5% of polyolefin 1 is added during the production process of the negative electrode plate, and 0.5% of polyether 3 is added during the production process of the separator, the rest is the same as in Example 1.

[0269] The test was carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0270] Comparative Example 4

[0271] Except that 15% of polycarbonate 2 is added during the production process of the positive electrode plate, 15% of polyolefin 1 is added during the production process of the negative electrode plate, and 15% of polyether 3 is added during the production process of the separator, the rest is the same as in Example 1.

[0272] The test was carried out according to the battery test method in Example 1, and the test results are shown in Table 2.

[0273] Table 1 Basic parameters of ionic polymers

[0274]

[0275] Table 2. Test results of battery performance

[0276]

[0277]

[0278] As can be seen from Table 1, the ionic polymers M w / M a used in Examples 1-10 are in the range of 2.02 - 1004.96, all greater than 2. At 60 °C, the swelling degree of the ionic polymer in the electrolyte is 55 - 250%, all greater than 50%, and the swelling loss rate is less than 5%.

[0279] As can be seen from Table 2, for the lithium-ion batteries obtained by adding the ionic polymer of the present invention to the coating materials of the electrodes or separators in Examples 1-10, the thickness expansion rate during high-temperature storage is 2.9-4.3%, the capacity retention rate during high-temperature storage is 90.3-92.4%, the capacity recovery rate during high-temperature storage is 93.5-95.8%, and the room-temperature cycle capacity retention rate after 1000 cycles is 92.5-93.8%. The results of the nail penetration test show that none of them catch fire or explode. In Comparative Example 1, the ionic polymer of the present invention was not added to either the electrode or the separator. In Comparative Example 2, an ionic polymer that can be mostly dissolved in the electrolyte was added to the negative electrode plate. In Comparative Example 3, less than 1% of the ionic polymer was added to both the electrode and the separator. The high-temperature storage performance of these groups of batteries is worse than that of Example 1, and fire occurs during the nail penetration test. In Comparative Example 4, more than 10% of the ionic polymer was added to the electrode. Although the battery does not catch fire or explode during the nail penetration test, it dives during the cycle. Therefore, for the lithium-ion batteries obtained by adding the ionic polymer of the present invention to the coating materials of the electrode materials or separators, the high-temperature storage performance and safety are significantly improved.

[0280] In summary, in the present invention, the ionic polymer is added to the positive electrode, negative electrode or separator. After the ionic polymer contacts the electrolyte, it can absorb the electrolyte and swell to form a gel electrolyte. The traditional production process can be adopted, avoiding the problems of complex process, unstable electrolyte, and difficulty in wetting the electrode caused by adding the gel polymer or its precursor to the electrolyte in the prior art, and can meet the requirements of high-energy-density batteries. At the same time, using the gel electrolyte instead of the liquid electrolyte can reduce the leakage of the electrolyte, the volatilization of the solvent, and the contact between the electrolyte and the surface of the active material, thereby improving the high-temperature cycle performance and safety performance of the battery, extending the service life of the battery, reducing the risk of battery fire and explosion, and having great application prospects.

[0281] Although this application is disclosed above with preferred embodiments, it is not used to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the protection scope of this application should be subject to the scope defined by the claims of this application. The above are only the preferred embodiments of the implementation of the present invention, and do not impose any formal limitations on the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention need to be included within the protection scope of the present invention.

Claims

1. A gel electrolyte lithium-ion battery comprising an ionic polymer, characterized in that, The invention comprises a positive electrode, a negative electrode, a separator and an electrolyte, wherein at least one of the positive electrode, the negative electrode or the separator comprises an ionic polymer, and the ionic polymer comprises w / M a 2-2000; Among them, M w is the weight-average molecular weight of the ionic polymer, M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol; At 25-60 °C, the swelling degree of the ionic polymer in the electrolyte is 50-500%, and the swelling loss rate of the ionic polymer in the electrolyte <5%; The positive electrode includes a current collector and a positive electrode material coated on the current collector, and the positive electrode material includes a positive electrode active material and the ionic polymer; And / or, the negative electrode includes a current collector and a negative electrode material coated on the current collector, and the negative electrode material includes a negative electrode active material and the ionic polymer; And / or, the separator includes a polymer microporous layer and a separator coating material coated on the polymer microporous layer, and the separator coating material includes inorganic particles and the ionic polymer.

2. The gel electrolyte lithium ion battery according to claim 1, characterized in that M in the ionic polymer w / M a is 2 - 1000.

3. The gel electrolyte lithium ion battery according to claim 2, wherein, M in the ionic polymer w / M a is 2 - 500.

4. The gel electrolyte lithium ion battery according to claim 1, wherein The M a is from 100 to 1000 g / mol.

5. The gel electrolyte lithium ion battery according to claim 1, characterized in that, Based on the total weight of the positive electrode material solids, the content of the ionic polymer is 1-10%; And / or, based on the total weight of the negative electrode material solids, the content of the ionic polymer is 1-10%; And / or, based on the total weight of the separator coating material solids, the content of the ionic polymer is 1-80%.

6. The gel electrolyte lithium ion battery according to claim 1, wherein The anion group of the ionic polymer is selected from one or more of carboxylate, sulfonate, sulfate, and phosphate.

7. The gel electrolyte lithium ion battery according to claim 6, characterized in that, The cation of the ionic polymer is selected from one or more of lithium ion, sodium ion, magnesium ion, calcium ion, barium ion, and aluminum ion.

8. The gel electrolyte lithium ion battery according to claim 1, wherein The ionic polymer is selected from one or more of the following polymers: polyether containing at least 2 anion groups, polyester containing at least 2 anion groups, polyolefin containing at least 2 anion groups, polycarbonate containing at least 2 anion groups, and polyamide containing at least 2 anion groups.

9. The gel electrolyte lithium ion battery according to claim 6, wherein, The ionic polymer is selected from one or more of the following polymers: polyether containing at least 2 anion groups, polyester containing at least 2 anion groups, polyolefin containing at least 2 anion groups, polycarbonate containing at least 2 anion groups, and polyamide containing at least 2 anion groups.

10. The gel electrolyte lithium-ion battery according to any one of claims 1-9, characterized in that, The ionic polymer is selected from one or more of the following polymers: Wherein, R1-R3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, or sulfur-containing substituted hydrocarbon group, and X1-X3 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group, or ionic group, and at least one of X1-X3 is an ionic group, and the ionic group includes an anion group and a cation, and m and n are both integers from 1 to 5000; Wherein, R4-R6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, or sulfur-containing substituted hydrocarbon group, and X4-X6 are each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group, or ionic group, and at least one of X4-X6 is an ionic group, and the ionic group includes an anion group and a cation, and m and n are both integers from 1 to 5000; Among them, R7-R 11 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, or a sulfur-containing substituted hydrocarbon group, X7-X 10 are each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group, or an ionic group, and X7-X 10 at least one of which is an ionic group, the ionic group including an anionic group and a cation, and n is an integer from 1 to 5000; wherein, R 12 -R 17 each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group or a sulfur-containing substituted hydrocarbon group, X 11 -X 14 each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group or an ionic group, and X 11 -X 14 at least one is an ionic group, the ionic group includes an anionic group and a cation, and l, m, and n are all integers from 1 to 5000; wherein, R 18 -R 20 each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 15 -X 17 each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X 15 -X 17 at least one is an ionic group, the ionic group includes anionic group and cation, and m and n are both integers from 1 to 5000; wherein, R 21 -R 23 each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group or sulfur-containing substituted hydrocarbon group, X 18 -X 20 each independently selected from hydrogen, hydrocarbon group, halogenated hydrocarbon group, oxygen-containing substituted hydrocarbon group, nitrogen-containing substituted hydrocarbon group, phosphorus-containing substituted hydrocarbon group, sulfur-containing substituted hydrocarbon group or ionic group, and X 18 -X 20 at least one is an ionic group, the ionic group includes anionic group and cation, and m and n are both integers from 1 to 5000; wherein, R 24 -R 28 each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group or a sulfur-containing substituted hydrocarbon group, X 21 -X 25 each independently selected from hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, an oxygen-containing substituted hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, a phosphorus-containing substituted hydrocarbon group, a sulfur-containing substituted hydrocarbon group or an ionic group, and X 21 -X 25 at least one is an ionic group, the ionic group comprising an anionic group and a cation, and n is an integer from 1 to 5000.

11. The gel electrolyte lithium ion battery according to any one of claims 1-9, characterized in that: The ionic polymer includes a polyolefin having at least two anionic groups on the polymer side chain, wherein the polyolefin is formed by copolymerizing an ethylenic monomer containing an ionic group and an ethylenic monomer without an ionic group, and the structural formula of the ethylenic monomer containing an ionic group is as follows: wherein, R1, R2, and R3 are each independently selected from a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group, or a halogen-containing substituted hydrocarbon group, R4 is selected from a hydrocarbon group, a nitrogen-containing substituted hydrocarbon group, an oxygen-containing substituted hydrocarbon group, or a halogen-containing substituted hydrocarbon group, X is an ionic group, and the ionic group includes an anionic group and a cation. The ethylenic monomer without an ionic group includes one or more of styrene, methylstyrene, acrylonitrile, acrylate, methacrylate, acrylamide, N-substituted methacrylamide, vinyl ether, N-vinylpyrrolidone, vinylpyridine, maleic anhydride, maleimide, vinylene carbonate, or vinyl ethyl carbonate.

12. The gel electrolyte lithium ion battery according to claim 11, wherein The electrolyte includes an organic solvent and a lithium salt.

13. The gel electrolyte lithium ion battery according to any one of claims 1-9, characterized in that, The organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and methyl propyl carbonate.

14. The gel electrolyte lithium ion battery according to claim 13, wherein The lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, and lithium bis(fluorosulfonyl)imide.

15. The gel electrolyte lithium ion battery according to claim 13, wherein The lithium salt is lithium hexafluorophosphate.

16. The gel electrolyte lithium ion battery according to claim 15, wherein The electrolyte includes an organic solvent and a lithium salt.

17. The gel electrolyte lithium ion battery according to claim 10, wherein The electrolyte includes an organic solvent and a lithium salt.

18. The gel electrolyte lithium ion battery according to claim 11, wherein, The electrolyte further includes one or more of an unsaturated cyclic carbonate, a fluorinated cyclic carbonate, a cyclic sultone, and a cyclic sulfate.

19. The gel electrolyte lithium ion battery according to claim 13, characterized in that, The unsaturated cyclic carbonate is selected from vinylene carbonate and / or vinyl ethyl carbonate, 20. The gel electrolyte lithium ion battery according to claim 19, wherein and / or, the fluorinated cyclic carbonate is selected from at least one of fluorinated ethylene carbonate, trifluoromethyl ethylene carbonate, or difluorinated ethylene carbonate, and / or, the cyclic sultone is selected from at least one of 1,3-propane sultone, 1,4-butane sultone, and allyl-1,3-sultone, and / or, the cyclic sulfate is selected from at least one of ethylene sulfate, propylene sulfate, and 4-methyl ethylene sulfate. The method includes the following steps: forming an electrode core with a positive electrode, a negative electrode, and a separator, placing the electrode core in a battery case, then injecting the electrolyte to obtain a semi-finished lithium ion battery, subjecting the semi-finished lithium ion battery to formation and degassing, and then sealing the liquid injection port of the battery case to obtain a gel electrolyte lithium ion battery.

21. The preparation method of the gel electrolyte lithium ion battery according to any one of claims 1-20, characterized in that, At 25-60 °C, the swelling degree of the ionic polymer in the electrolyte is 50-500%, and the swelling loss rate of the ionic polymer in the electrolyte < 5%.

22. A lithium-ion battery electrode, characterized in that, It includes a current collector and an electrode material coating coated on the current collector, wherein the electrode material coating contains an ionic polymer and an active substance, and in the ionic polymer, M w / M a is 2 - 2000, where M w is the weight-average molecular weight of the ionic polymer, and M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein, and the M a is 100 - 2000 g / mol; Based on the total solid weight of the electrode material, the addition amount of the ionic polymer is 1-10%.

23. The lithium-ion battery electrode according to claim 22, characterized in that, The electrode is a positive electrode or a negative electrode.

24. The lithium ion battery electrode according to claim 22, wherein, At 25-60 °C, the swelling degree of the ionic polymer in the electrolyte is 50-500%, and the swelling loss rate of the ionic polymer in the electrolyte < 5%.

25. A lithium-ion battery separator, characterized in that, It includes a polymer microporous layer and a separator coating material coated on the polymer microporous layer, wherein the separator coating material includes inorganic particles and an ionic polymer, and in the ionic polymer, M w / M a is 2 - 2000, where M w is the weight-average molecular weight of the ionic polymer, and M a is the ratio of the mass of the ionic polymer to the number of moles of anionic groups contained therein. The M a is 100 - 2000 g / mol; Based on the total solid weight of the separator coating material, the addition amount of the ionic polymer is 1-80%.

26. The separator for a lithium ion battery according to claim 25, wherein ​ 27. The separator for a lithium ion battery according to claim 25, wherein The polymer microporous layer is a polyolefin microporous membrane or a non-woven fabric.

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