High-temperature-resistant long-life lithium-ion or sodium-ion battery and preparation method therefor

Abstract

A high-temperature-resistant long-life lithium-ion or sodium-ion battery and a preparation method therefor. The lithium-ion battery or the sodium-ion battery comprises a positive electrode, a negative electrode, a separator and an electrolyte. The positive electrode comprises a current collector and a positive electrode coating material loaded on the current collector, and the positive electrode coating material comprises a positive electrode active substance containing a transition metal and a polymer containing a coordination group, wherein the coordination groups can be coordinated with the transition metal ions in the positive electrode active substance, and the polymer containing the coordination group has a swelling degree of 5-50% in the electrolyte at 25-60ºC. By coordinating the coordination groups of the polymer with the transition metal ions, the polymer can be firmly adsorbed on the surface of the positive electrode active substance, forming a stable protective layer, inhibiting the oxidation of the electrolyte and the dissolution of transition metal ions, and thus greatly improving the high temperature performance and safety of the lithium-ion battery or the sodium-ion battery.

Description

A high-temperature-resistant, long-life lithium-ion or sodium-ion battery and its preparation method Technical Field

[0001] The present invention relates to the fields of lithium ion batteries and sodium ion batteries, and in particular to a high-temperature resistant and long-life lithium ion battery or sodium ion battery and a preparation method thereof. Background Art

[0002] Lithium batteries, due to their high energy density, have been widely used in portable electronic devices such as mobile phones, tablets, and laptops, as well as in new energy vehicles and energy storage applications. Sodium batteries have also attracted considerable attention due to their low cost, high energy density, and excellent high- and low-temperature performance. High-energy-density lithium-ion batteries typically utilize transition metal oxide cathode active materials, such as lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium iron phosphate. Sodium-ion batteries also commonly utilize transition metal oxide cathode active materials, such as sodium nickel oxide, sodium cobalt oxide, sodium manganese oxide, sodium nickel iron manganese oxide, and sodium copper iron manganese oxide, due to their high operating potential and high specific capacity. However, the transition metal ions on the surface of these transition metal oxide cathode active materials exhibit certain instabilities, which can lead to oxidative decomposition in the electrolyte. Furthermore, the transition metal ions themselves can be corroded and dissolved into the electrolyte by trace amounts of hydrogen fluoride in the electrolyte, both of which can degrade battery performance. Specifically, oxidative decomposition of the electrolyte consumes electrolyte, reducing cycle life, and also generates gas, causing battery swelling and posing a safety hazard. Transition metal ions dissolved in the electrolyte migrate to the negative electrode and are reduced, damaging the negative electrode SEI, leading to a decrease in cycling performance. The reduced transition metals may even form dendrites that pierce the separator, causing a short circuit and posing a serious safety hazard. This performance degradation and safety risk caused by the oxidative decomposition of the electrolyte and the dissolution of transition metal ions are particularly prominent at high temperatures or at a charge cutoff voltage above 4.3V.

[0003] Therefore, certain specific additives such as 1.3-propane sultone or 1.3-propylene sultone are usually added to the electrolyte of lithium-ion batteries or sodium-ion batteries. These additives can decompose on the surface of the positive electrode active material to form a certain protective layer, inhibiting the decomposition of the electrolyte and the dissolution of transition metal ions. However, this method has a disadvantage. We cannot allow these additives to act only on the positive electrode. They will also be reduced to form SEI on the negative electrode. The negative electrode SEI formed by these additives usually has a high impedance problem, which will lead to the deterioration of the charging performance of lithium-ion batteries or sodium-ion batteries, and even cause the formation of lithium / sodium dendrites on the negative electrode surface during charging, posing a serious safety hazard. Summary of the Invention

[0004] The problem to be solved by the present invention is: In lithium-ion batteries or sodium-ion batteries using transition metal oxide positive electrode active materials, there are problems of oxidative decomposition of the electrolyte and dissolution of transition metal ions into the electrolyte on the surface of the positive electrode active material, which will lead to deterioration of battery performance and may cause safety hazards. This performance deterioration and safety risks caused by oxidative decomposition of the electrolyte and dissolution of transition metal ions are particularly prominent at high temperatures or at a charging cut-off voltage of 4.3V or above.

[0005] In view of the above problems, the object of the present invention is to provide a lithium ion battery or a sodium ion battery and a preparation method thereof.

[0006] In order to solve the above problems, the technical solutions of the present invention are as follows:

[0007] In the first aspect, the present application provides a lithium-ion battery or a sodium-ion battery, which includes a positive electrode, a negative electrode, a separator and an electrolyte, wherein the positive electrode includes a current collector and a positive electrode coating material loaded on the current collector, the positive electrode coating material includes a positive electrode active substance containing a transition metal and a polymer containing a coordination group, wherein the coordination group can coordinate with the transition metal ions in the positive electrode active substance, and at 25-60°C, the swelling degree of the polymer containing the coordination group in the electrolyte is 5-50%.

[0008] In some embodiments of the present application, the coordinating group contains one or more of cyano, carbonyl, pyridyl, pyrazinyl, pyrimidinyl, furyl, pyrrolyl, thienyl, thiazolyl and oxazolyl.

[0009] In some embodiments of the present application, the coordination group contains two or more atoms that can coordinate with the same transition metal ion.

[0010] In some embodiments of the present application, the ligand group includes one or more of the following structures:

[0011] wherein R1 is selected from one of 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; R2 and R4 are each independently selected from one of 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; R3 is selected from one of 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 is selected from S, NH or O; and X2 is selected from S or O.

[0012] In some embodiments of the present application, the polymer containing a coordination group is selected from one or more of polyolefins, polyesters, polyamides, polyurethanes and polyimides.

[0013] In some embodiments of the present application, the content of the polymer containing a coordination group is 0.1-10%, preferably 0.2-5%, more preferably 0.2-2%, and further preferably 0.5-2%, based on the total weight of the solid content of the positive electrode coating material loaded on the current collector.

[0014] In some embodiments of the present application, the transition metal is selected from one or more of nickel, cobalt, manganese, copper and iron.

[0015] In some embodiments of the present application, the electrolyte includes an organic solvent; preferably, the organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate and propyl propionate;

[0016] Preferably, in the lithium battery, the electrolyte further comprises a lithium salt, and the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide, or,

[0017] In the sodium battery, the electrolyte further comprises a sodium salt, and the sodium salt is selected from one or more of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium bis(trifluoromethylsulfonyl)imide and sodium bis(trifluoromethylsulfonyl)imide.

[0018] In some embodiments of the present application, the electrolyte further comprises one or more of unsaturated cyclic carbonates, fluorinated cyclic carbonates, cyclic sultones, and cyclic sulfates;

[0019] Preferably, the unsaturated cyclic carbonate is selected from vinylene carbonate and / or vinyl ethylene carbonate, and / or the fluorinated cyclic carbonate is selected from at least one of fluorinated ethylene carbonate, trifluoromethyl ethylene carbonate or bisfluoroethylene carbonate, and / or the cyclic sultone is selected from at least one of 1,3-propane sultone, 1,4-butane sultone and propenyl-1,3-sultone, and / or the cyclic sulfate is selected from at least one of vinyl sulfate, propenyl sulfate and 4-methylvinyl sulfate.

[0020] In a second aspect, the present application also provides a method for preparing the above-mentioned lithium-ion battery or sodium-ion battery, the preparation method comprising forming a battery core with a positive electrode, a negative electrode and a separator, placing the battery core in a battery casing, and then injecting an electrolyte to obtain a semi-finished lithium-ion battery or a semi-finished sodium-ion battery, forming and exhausting the semi-finished lithium-ion battery or semi-finished sodium-ion battery, and then sealing the liquid injection port of the battery casing to obtain a lithium-ion battery or sodium-ion battery.

[0021] The positive electrode is obtained by coating a positive electrode coating material on a current collector, drying, rolling and cutting. The positive electrode coating material is obtained by mixing the polymer containing the coordination group with a solvent and then mixing it with a positive electrode active material, a conductive agent and a binder.

[0022] In a third aspect, the present application also provides a positive electrode coating material, which comprises a positive electrode active material containing a transition metal and a polymer containing a coordination group; preferably, the positive electrode coating material also contains a conductive agent and a binder.

[0023] In a fourth aspect, the present application also provides a method for preparing the above-mentioned positive electrode coating material, which comprises mixing the polymer containing the coordination group with a solvent and then mixing it with a positive electrode active material, a conductive agent and a binder.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention adds a polymer containing a coordinating group to the positive electrode material. The coordinating group in the polymer can coordinate with the transition metal ions on the surface of the positive electrode active material, so that the polymer containing the coordinating group can be firmly adsorbed on the surface of the active material to form a stable protective layer, inhibiting the oxidation of the electrolyte and the dissolution of the transition metal ions, thereby significantly improving the high-temperature performance of the lithium-ion battery or sodium-ion battery and improving the safety of the lithium-ion battery or sodium-ion battery. At the same time, the polymer containing the coordinating group has a low swelling degree in the electrolyte (swelling degree less than 50%). Thus, the protective layer formed by the polymer containing the coordinating group can effectively inhibit the oxidative decomposition of the electrolyte and the dissolution of the transition metal ions on the surface of the positive electrode active material, thereby improving the service life and safety of the battery. Moreover, the polymer containing the coordinating group has a certain ionic conductivity after swelling in the electrolyte, allowing lithium ions or sodium ions to be embedded in the positive electrode active material through the protective layer or to be released from the positive electrode active material and then enter the electrolyte through the protective layer. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and technical effects of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described. The embodiments described below are part of the embodiments of the present application, not all of them. In combination with the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In order to better understand the above technical solution, this application is further described in detail below.

[0028] In a first aspect, in a specific embodiment of the present application, the present invention provides a lithium-ion battery or a sodium-ion battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode comprises a current collector and a positive electrode coating material supported on the current collector, the positive electrode coating material comprising a positive electrode active material containing a transition metal and a polymer containing a ligand group, wherein the ligand group is capable of coordinating with the transition metal ions in the positive electrode active material, and the polymer containing the ligand group has a swelling degree of 5-50% in the electrolyte at 25-60° C. The reason for controlling the swelling degree within the above range is that when the swelling degree is too low, the ionic conductivity of the polymer layer is low, resulting in a large internal resistance of the battery, and when the swelling degree is too high, the polymer layer cannot effectively inhibit side reactions between the electrolyte and the surface of the active material, thereby failing to significantly improve high-temperature performance and safety.

[0029] In some embodiments of the present application, the coordinating group comprises one or more of a cyano group, a carbonyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a furyl group, a pyrrolyl group, a thienyl group, a thiazolyl group and an oxazolyl group.

[0030] In some embodiments of the present application, the coordination group comprises two or more atoms capable of coordinating with the same transition metal ion.

[0031] In some embodiments of the present application, the ligand is composed of two or three adjacent functional groups selected from cyano, carbonyl, pyridyl, pyrazinyl, pyrimidinyl, furyl, pyrrolyl, thienyl, thiazolyl and oxazolyl, and the functional groups are in a suitable spatial arrangement so that the oxygen atoms and / or nitrogen atoms on these functional groups can coordinate with the same transition metal ion. Examples of the ligand include any of the following structures: a structure with a cyano and / or carbonyl group on or adjacent to the ring of pyridine, bipyridine, pyrimidine, pyrazine or furan, a structure containing two adjacent cyano groups, a structure containing adjacent cyano and carbonyl groups, and a structure containing two adjacent carbonyl groups.

[0032] It should be noted that the term "adjacent" refers to the position where the oxygen atom or nitrogen atom on the functional group can achieve coordination with the same transition metal ion, and may be adjacent or non-adjacent.

[0033] In some embodiments of the present application, the ligand group includes one or more of the following structures:

[0034] wherein R1 is selected from one of 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; R2 and R4 are each independently selected from one of 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; R3 is selected from one of 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 is selected from S, NH or O; and X2 is selected from S or O.

[0035] It should be noted that the wavy line in the molecular formula described herein represents the connection with the polymer chain, R1 is a substituent group on the aromatic ring, and when R1 is hydrogen, it indicates that the position is not substituted by a substituent group.

[0036] The advantage of using the above-mentioned coordination group is that this coordination group is a multidentate ligand that can form a more stable coordination effect with the transition metal ion (as shown in Formula 24), so that the polymer containing the coordination group can be more stably adsorbed on the surface of the positive electrode active material particles, which is conducive to forming a more complete and stable protective layer, thereby more effectively inhibiting the decomposition reaction of the electrolyte on the surface of the positive electrode active material.

[0037] wherein R1 is selected from one of hydrogen, hydrocarbon, halogenated hydrocarbon, oxygen-containing substituted hydrocarbon, nitrogen-containing substituted hydrocarbon, phosphorus-containing substituted hydrocarbon or sulfur-containing substituted hydrocarbon, and M n+ For transition metal ions.

[0038] In some embodiments of the present application, the polymer containing a coordination group is selected from one or more of polyolefins, polyesters, polyamides, polyurethanes and polyimides.

[0039] In this application, polyolefins, polyesters, polyamides, polyurethanes and polyimides are classified according to the difference in main chain structure.

[0040] Among them, the synthesis route of polyolefins can be: obtained by free radical polymerization of monomers containing carbon-carbon double bonds under the action of an initiator. Common monomers containing carbon-carbon double bonds include acrylonitrile, acrylate, methacrylate, cyanoacrylate, N-vinyl pyrrolidone, vinyl pyridine, N,N-dimethylacrylamide, etc.

[0041] The synthetic routes of polyester are divided into two categories. The main chain of one category is obtained by ring-opening polymerization of lactone monomers initiated by polyols or polycarboxylic acids or hydroxycarboxylic acid-containing initiators. The synthetic routes are respectively to use polyols or polycarboxylic acids or hydroxycarboxylic acid-containing compounds as initiators to initiate ring-opening polymerization of lactone monomers to obtain polyester polyols or polyester polyacids or polyesters containing multiple hydroxyl groups and carboxylic acids at the same time. Representative polyols include ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, inositol, etc. Representative polycarboxylic acids include succinic acid, triacylglycerol, trimesic acid, butane tetracarboxylic acid, etc. Carboxylic acids, pyromellitic acid, etc. Representative initiators containing hydroxycarboxylic acids include glycolic acid, malic acid, citric acid, tartaric acid, etc. Representative lactone monomers include glycolide, lactide, δ-valerolactone, ε-caprolactone, etc.; the other type of main chain is obtained by the condensation reaction of diacid monomers and diol monomers, and its synthesis route is to obtain polyester polyols by the condensation reaction of diacid monomers and diol monomers. Representative diacids include succinic acid, adipic acid, terephthalic acid, etc., and representative diols include ethylene glycol, 1,3-propylene glycol, 1,6-hexanediol, etc.

[0042] The synthesis routes of polyamides are divided into two categories. The main chain of one category is obtained by ring-opening polymerization of caprolactam monomers initiated by alkali metals or water to obtain polyamides with amino groups and carboxylate groups at both ends. Representative alkali metal initiators include sodium hydroxide and sodium methoxide. The main chain of the other category is obtained by condensation polymerization of dibasic acid monomers and diamine monomers. Its synthesis route is to obtain polyamide by condensation polymerization of dibasic acid monomers and diamine monomers. Representative dibasic acids include succinic acid, adipic acid, terephthalic acid, etc., and representative diamines include ethylenediamine, hexamethylenediamine, polyetheramine, p-phenylenediamine, etc.

[0043] The synthesis route of polyimide can be to first react a dibasic acid anhydride and a diamine to form polyamic acid, and then perform an imidization reaction at high temperature to obtain it. Representative dibasic acid anhydrides include 4,4'-biphenyl ether dianhydride, bisphenol A diether dianhydride, 4,4'-carbonyl diphthalic anhydride, etc. Representative diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, polyetheramine, etc.

[0044] The synthesis route of polyurethane can be a polyurethane generated by the reaction of diols and diisocyanates. Representative diols include polyethylene glycol, terminal hydroxyl polycaprolactone, and terminal hydroxyl polyester oligomers obtained by polycondensation of diols and dibasic acids. Representative diisocyanates include hexamethylene diisocyanate and toluene diisocyanate.

[0045] In some embodiments of the present application, the polymer containing a coordination group includes, but is not limited to, one or more of polyolefin 1, polyolefin 2, polyolefin 3, polyolefin 4, polyolefin 5, polyolefin 6, polyolefin 7, polyolefin 8, polyolefin 9, polyolefin 10, polyolefin 11, polyolefin 12, polyolefin 13, polyolefin 14, polyolefin 15, polyolefin 16, polyolefin 17, polyolefin 18, polyolefin 19, polyolefin 20, polyolefin 21, polyolefin 23, polyester 1, polyester 2, polyester 3, polyester 4, polyester 5, polyester 6, polyester 7, polyamide 1, polyamide 2, polyamide 3, polyamide 4, polyamide 5, polyurethane 1, and polyimide 1, preferably one or more of polyolefin 1, polyolefin 2, polyolefin 3, polyolefin 10, polyolefin 11, polyolefin 13, polyester 1, polyester 2, polyester 3, polyester 6, polyester 7, polyamide 1, polyamide 2, polyurethane 1, and polyimide 1. For details of the above polymers, please refer to the description of the embodiments.

[0046] In some embodiments of the present application, the content of the polymer containing a ligand group is 0.1-10%, preferably 0.2-5%, more preferably 0.2-2%, and even more preferably 0.5-2%, based on the total weight of the solid content of the positive electrode coating material supported on the current collector. The reason for selecting the above preferred range of polymer addition is that: if the polymer content is too low, the polymer cannot effectively cover the surface of the active material, and the effect of improving high-temperature performance and safety is not significant; if the polymer content is too high, on the one hand, it affects ion transport, increases the internal resistance of the battery, and on the other hand, it reduces the energy density of the battery.

[0047] In some embodiments of the present application, the polymer containing a coordinating group has a swelling degree of 5-45% in the electrolyte at 25-60°C, and preferably a swelling loss rate of less than 2%. When the swelling degree of the polymer containing a coordinating group is controlled within the range of the present invention, the protective layer formed by the polymer containing a coordinating group can effectively inhibit the oxidative decomposition of the electrolyte and the dissolution of transition metal ions. At the same time, after swelling in the electrolyte, the polymer containing a coordinating group has a certain ionic conductivity, allowing lithium ions or sodium ions to be embedded in the positive electrode active material through the protective layer or to be released from the positive electrode active material and then enter the electrolyte through the protective layer.

[0048] It should be noted that the swelling degree described in the present invention refers to the ratio of the mass difference before and after the polymer containing the coordination group is immersed in the electrolyte to the mass of the polymer before immersion. The specific test method is: the polymer containing the coordination group is made into a circular thin film sheet with a thickness of 30μm and a size of 16mm*16mm, the mass of the film is weighed, the film is immersed in 10g of electrolyte, and the film is sealed and stored at a certain temperature (for example, 60°C). Every 8 hours, the film is taken out, the electrolyte on the surface is wiped off, the thickness is measured and weighed, and then it is put back into the electrolyte and sealed and continued to be stored at a certain temperature (for example, 60°C) until the thickness and mass of the film remain unchanged after three consecutive tests. It is considered that the polymer sheet containing the coordination group has reached a swelling equilibrium state. The swelling degree is calculated according to the following formula:

[0049] In the above formula, m0 represents the mass of the polymer membrane containing the coordination group before immersion in the electrolyte, and m1 represents the mass of the polymer membrane containing the coordination group when the swelling equilibrium is reached after immersion in the electrolyte.

[0050] The swelling loss rate mentioned in this application refers to the ratio of the mass loss caused by the partial dissolution of the polymer into the electrolyte when the polymer containing the coordination group swells in the electrolyte to the mass of the polymer before swelling. The specific test method is: the polymer containing the coordination group 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, and the film is sealed and stored at a certain temperature (for example, 60 ° C). The film is taken out every 8 hours, the electrolyte on the surface is wiped off, the thickness is measured and weighed, and then it is put back into the electrolyte and sealed and continued to be stored at a certain temperature (for example, 60 ° C) until the thickness and mass of the film remain unchanged after three consecutive tests, the excess electrolyte and lithium salt on the film are rinsed off with solvent dimethyl carbonate (DMC), and it is completely dried in an oven. The mass of the remaining film after drying is weighed, and the swelling loss rate is calculated according to the following formula:

[0051] In the above formula, m0 represents the mass of the polymer membrane containing coordination groups before immersion in the electrolyte, and the unit is g; m2 represents the mass of the polymer membrane containing coordination groups remaining after immersion in the electrolyte and then washing and drying, and the unit is g.

[0052] In some embodiments of the present application, the electrolyte includes an organic solvent. Preferably, the non-aqueous organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate and propyl propionate.

[0053] In some embodiments of the present application, in the lithium battery, the electrolyte further comprises a lithium salt, and the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide, or

[0054] In the sodium battery, the electrolyte further comprises a sodium salt, and the sodium salt is selected from one or more of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium bis(trifluoromethylsulfonyl)imide and sodium bis(trifluoromethylsulfonyl)imide.

[0055] In some embodiments of the present application, the electrolyte further comprises 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 ethylene carbonate, and / or the fluorinated cyclic carbonate is selected from at least one of fluorinated ethylene carbonate, trifluoromethyl ethylene carbonate or bisfluoroethylene carbonate, and / or the cyclic sultone is selected from at least one of 1,3-propane sultone, 1,4-butane sultone and propenyl-1,3-sultone, and / or the cyclic sulfate is selected from at least one of vinyl sulfate, propenyl sulfate and 4-methylvinyl sulfate.

[0056] In some embodiments of the present application, the positive electrode includes a current collector and a positive electrode coating material loaded on the current collector. The current collector can be various current collectors familiar to those skilled in the art, such as aluminum foil, carbon-coated aluminum foil, and aluminum-plated polymer film; the positive electrode coating material includes a positive electrode active substance containing a transition metal and the above-mentioned polymer containing a coordination group.

[0057] In the present application, the transition metal in the positive electrode active material is selected from one or more of nickel, cobalt, manganese, copper and iron.

[0058] It is understood that the above-mentioned positive electrode coating material also includes a positive electrode conductor and a binder; the above-mentioned positive electrode active material is not limited to lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2, where x≥0, y≥0, x+y≤1.0), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), sodium nickel iron manganese oxide (NaNi x Fe y Mn 1-x-y O2, where x≥0, y≥0, x+y≤1.0), sodium copper iron manganate (Na 0.9 Cu x Fe y Mn 1-x-yO2, wherein x≥0, y≥0, x+y≤1.0); the positive electrode conductive agent includes but is not limited to one or more of carbon black, carbon nanotubes (CNTs), flake graphite, Ketjen black, and VGCF; the binder includes but is not limited to one or more of polyvinylidene fluoride (PVDF), copolymers of vinylidene fluoride (VF2), and polyimide.

[0059] In some embodiments of the present application, the negative electrode includes a current collector and a negative electrode coating 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, and copper-plated polymer film; the negative electrode coating material includes a negative electrode active substance.

[0060] It is understandable that the above-mentioned negative electrode coating material also includes a negative electrode conductor and a binder; the above-mentioned negative electrode active material includes but is not limited to artificial graphite (C), silicon carbon, silicon oxygen or mesophase carbon microspheres; the conductive agent includes but is not limited to one or more of carbon black, carbon nanotubes (CNT), flake graphite, Ketjen black, and VGCF; the binder includes but is not limited to one or more of styrene-butadiene rubber emulsion (SBR), sodium carboxymethyl cellulose (CMC), and polyacrylic acid polymer (PAA).

[0061] In some embodiments of the present application, the separator includes a polymer porous membrane and a separator coating material coated on the polymer porous membrane; the separator coating material includes inorganic particles.

[0062] It can be understood that the above-mentioned insulator coating material also includes a binder, which includes but is not limited to one or more of polyvinylidene fluoride (PVDF), styrene-butadiene rubber emulsion (SBR), and sodium carboxymethyl cellulose (CMC); the inorganic particles include but are not limited to at least one of alumina, boehmite, calcium carbonate, hydrotalcite, montmorillonite, spinel, titanium dioxide, silicon dioxide, zirconium oxide and silicon carbide.

[0063] In a second aspect, the present invention also provides a method for preparing the above-mentioned lithium ion battery or sodium ion battery, comprising the following steps: forming a battery core with a positive electrode, a negative electrode, and a separator, placing the battery core in a battery housing, and then injecting an electrolyte to obtain a semi-finished lithium ion or semi-finished sodium ion battery; forming and exhausting the semi-finished lithium ion or semi-finished sodium ion battery, and then sealing the liquid injection port of the battery housing to obtain a lithium ion battery or sodium ion battery;

[0064] The positive electrode is obtained by coating a positive electrode coating material on a current collector, drying, rolling and cutting. The positive electrode coating material is obtained by mixing the above-mentioned polymer containing coordination groups with a solvent and then mixing it with a positive electrode active material, a conductive agent and a binder.

[0065] In some embodiments of the present application, the content of the above-mentioned polymer containing a coordination group is 0.1-10%, preferably 0.2-5%, more preferably 0.2-2%, and further preferably 0.5-2%, based on the total weight of the solid content of the positive electrode coating material loaded on the current collector.

[0066] In a third aspect, the present application also provides a positive electrode coating material, which comprises a positive electrode active material containing a transition metal and a polymer containing a coordination group; preferably, the positive electrode coating material also contains a conductive agent and a binder.

[0067] In a fourth aspect, the present application also provides a method for preparing the above-mentioned positive electrode coating material, which comprises mixing the above-mentioned polymer containing a coordination group with a solvent and then mixing it with a positive electrode active material, a conductive agent and a binder.

[0068] The present application will be further described below with reference to the following examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application.

[0069] The raw materials or reagents used in this application are all purchased from the mainstream manufacturers in the market. The manufacturer or concentration is not specified. They are all analytically pure raw materials or reagents that can be routinely obtained. As long as the desired effect can be achieved, there are no particular restrictions. The instruments and equipment used in the present embodiment are all purchased from the main manufacturers in the market. As long as the desired effect can be achieved, there are no particular restrictions. In the present embodiment, the specific technology or conditions are not specified. The technology or conditions described in the document in this area or the product instructions are used.

[0070] Reagents:

[0071] Azobisisobutyronitrile, polyethylene glycol methyl ether methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, N-methylpyrrolidone, boric acid, oxalic acid, acrylonitrile, methyl methacrylate, acrylamide, 2-picolinic acid, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, 2-pyrazine formate, N,N-dimethylformamide, 6-cyanonicotinic acid, dibenzoyl peroxide, maleic anhydride, butyl acrylate, tert-butyl acrylate, hydroxyethyl methacrylate, 2,2-bipyridine-5-carboxylic acid, N,N-dimethylacrylamide, ethyl cyanoacrylate, 2-aminopyridine, cyanoacetic acid, 2- Hydroxypyridine, pyromellitic acid, δ-valerolactone, succinic acid, ethylene glycol, oxalic acid, acetonitrile, hexamethylenediamine, pentamethylenediamine, 2,5-furandicarboxylic acid, thiophene-2-carboxylic acid, 2,5-thiophenedicarboxylic acid, furoic acid, tetrabutyl titanate, 2,3-pyridinedicarboxylic anhydride, 2,3-pyrazine dianhydride, 4,4'-diaminodiphenyl ether, adipic acid, ε-caprolactone, toluene-2,4-diisocyanate, 4,4'-diphenyl ether dianhydride, 4-vinylpyridine, 4,6-diaminopyrimidine, benzidine disulfonic acid, and ethyl methacrylate were purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0072] 5-Cyano-furan-2-carboxylic acid, oxazole-5-carboxylic acid, and 2-methylthiazole-5-carboxylic acid were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0073] 5-Vinylpyridinium carboxylate and allylsulfonic acid were purchased from Shenzhen Chuangxin Biotechnology Co., Ltd.;

[0074] 4-Vinylpyridin-2-amine was purchased from Shenzhen Zhenqiang Biotechnology Co., Ltd.;

[0075] 2-Vinylpyrazine and 5-cyanothiophene-2-carboxylic acid were purchased from Beijing Bailingwei Technology Co., Ltd.;

[0076] 5-Cyanothiazole-2-carboxylic acid and 1H-pyrrole-2,5-dicarboxylic acid were purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd.;

[0077] Polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O2 was purchased from Hubei Rongbai Lithium Battery Materials Co., Ltd.;

[0078] Conductive agent PVDF binder Purchased from SOLVAY (SHANGHAI) Co., Ltd.

[0079] Artificial graphite was purchased from Tianjin Better New Energy Technology Co., Ltd.

[0080] Hereinafter, the present application will be described in more detail using various preparation examples, embodiments, and comparative examples, but the technical scope of the present application is not limited to these examples. It should be noted that, unless otherwise specifically stated, all percentages, parts, and ratios used in the present application are based on mass.

[0081] Preparation Example 1

[0082] 1. Add 16.4 g of azobisisobutyronitrile (AIBN, 0.1 mol), 385 g of tert-butyl acrylate (tBA, 3 mol), and 622 g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS, 3 mol) to a reactor. The molar ratio of AIBN, tBA, and AMPS is 1:30:30. Then, add 2 kg of N-methylpyrrolidone (NMP) as a solvent. React at 70 ° C under nitrogen protection for 10 hours, and then stop the reaction.

[0083] 2. Add 186g of boric acid (3mol) and 270g of oxalic acid (3mol) to a flask with a molar ratio of boric acid to oxalic acid of 1:1. Then add 1kg of NMP as a solvent and react at 100°C while vacuuming to remove the water produced by the reaction. Stop the reaction after 12 hours and test the solid content.

[0084] 3. The NMP solution of the product synthesized in step (2) (116 g of solid product) was added to the polymer solution in step (1), with the molar ratio of the product in step (2) to the polymer in step (1) being 10:1. The reaction was carried out at 100° C., and the water produced by the reaction was continuously removed by vacuuming. The reaction was stopped after 12 hours, and 148 g of lithium carbonate was added. The reaction was stirred at room temperature for 5 hours, and the excess lithium carbonate was filtered off. The filtrate was collected and vacuum dried to obtain a polyolefin 1 containing a coordination group, the structural formula of which is as follows:

[0085] Preparation Example 2

[0086] 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 352 g of acrylamide (EGME, 4 mol) were added to a reactor in a molar ratio of AIBN, AN, MMA and EGME of 1:60:20:20. 1.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and reacted at 70° C. under nitrogen for 10 h. The reaction was stopped, and 492 g of 2-pyridinecarboxylic acid (4 mol) and 18 g of sulfuric acid as a catalyst were added and reacted at 150° C. while vacuuming off the water produced by the reaction. After 10 h, the reaction was stopped, and 150 g of NaOH aqueous solution (solid content 10%) was added to neutralize the sulfuric acid. The water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 2 containing a coordination group, the structural formula of which is as follows:

[0087] Preparation Example 3

[0088] 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 284 g of acrylamide (MA, 4 mol) were added to a reactor in a molar ratio of AIBN, AN, MMA and MA of 1:60:20:20. 1.2 kg of N-methylpyrrolidone (NMP) was added as a solvent and reacted at 70° C. under nitrogen for 10 h. The reaction was stopped, and 496 g of 2-pyrazine formate (4 mol) and 18 g of sulfuric acid as a catalyst were added and reacted at 150° C. while vacuuming off the water produced by the reaction. After 10 h, the reaction was stopped, and 150 g of a NaOH aqueous solution (solid content 10%) was added to neutralize the sulfuric acid. The water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain a polyolefin 3 containing a coordination group, the structural formula of which is as follows:

[0089] Preparation Example 4

[0090] 3.3 g of azobisisobutyronitrile (AIBN, 0.02 mol), 530 g of acrylonitrile (AN, 10 mol), 384 g of butyl acrylate (BA, 3 mol) and 260 g of hydroxyethyl methacrylate (HEMA, 2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA to HEMA of 1:500:150:100. 1.2 kg of N,N-dimethylformamide (DMF) was added as a solvent and reacted at 70° C. under nitrogen for 10 h. The reaction was stopped, and 296 g of 6-cyanonicotinic acid (4 mol) and 20 g of sulfuric acid as a catalyst were added and reacted at 120° C. while removing the generated water under vacuum. After 10 h, the reaction was stopped, and 167 g of NaOH aqueous solution (solid content 10%) was added to neutralize the sulfuric acid. The water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 4 containing a coordination group, the structural formula of which is as follows:

[0091] Preparation Example 5

[0092] 16.4 g of azobisisobutyronitrile (AIBN, 0.1 mol), 212 g of acrylonitrile (AN, 4 mol), 100 g of methyl methacrylate (MMA, 1 mol) and 240 g of 4-vinylpyridin-2-amine (2 mol) were added to a reactor in a molar ratio of AIBN, AN, MMA to 4-vinylpyridin-2-amine of 1:40:10:20. 1 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 cyanoacetic acid (170 g, 2 mol) and 20 g of p-toluenesulfonic acid as a catalyst were added. The reaction was carried out at 150° C. while vacuuming off the generated water. After 10 h, the reaction was stopped, and 46 g of a NaOH aqueous solution (solid content 10%) was added to neutralize the p-toluenesulfonic acid. The water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain a polyolefin 5 containing a coordination group, the structural formula of which is as follows:

[0093] Preparation Example 6

[0094] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 265 g of acrylonitrile (AN, 5 mol), 192 g of butyl acrylate (BA, 1.5 mol) and 65 g of hydroxyethyl methacrylate (HEMA, 0.5 mol) were added to a reactor, with the molar ratio of AIBN, AN, BA and HEMA being 1:500:150:50. 0.8 kg of N-methylpyrrolidone (NMP) was added as a solvent, and the mixture was reacted at 70°C under nitrogen protection for 10 h. The reaction was stopped, and 100 g of 2,2-bipyridine-5-carboxylic acid (0.5 mol) and 15 g of sulfuric acid as a catalyst were added, and the mixture was reacted at 130°C while vacuuming off the water produced by the reaction. The reaction was stopped after 10 h, and 125 g of NaOH aqueous solution (solid content 10%) was added to neutralize the sulfuric acid. The water was removed by rotary evaporation at 80°C, and the insoluble matter was filtered off. The filtrate was collected and dried under vacuum to obtain polyolefin 6 containing a coordination group, the structural formula of which is as follows:

[0095] Preparation Example 7

[0096] 8.2 g of azobisisobutyronitrile (AIBN, 0.05 mol), 106 g of acrylonitrile (AN, 2 mol), 200 g of methyl methacrylate (MMA, 2 mol) and 149 g of 5-vinylpyridine carboxylate (VPA, 1 mol) were added to a reactor in a molar ratio of AIBN, AN, MMA and VPA of 1:40:40:20. 0.5 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70° C. under nitrogen protection for 10 h. The reaction was stopped, and 300 g of a LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups. The mixture was then vacuum dried to obtain polyolefin 7 containing a coordination group, the structural formula of which is as follows:

[0097] Preparation Example 8

[0098] 24.2 g of dibenzoyl peroxide (BPO, 0.1 mol), 530 g of acrylonitrile (AN, 3 mol), 198 g of N,N-dimethylacrylamide (DMAA, 2 mol) and 144 g of acrylic acid (AA, 2 mol) were added to a reactor in a molar ratio of BPO, AN, DMAA and AA of 1:30:20:20. 1.0 kg of N,N-dimethylformamide (DMF) was added as a solvent and reacted at 90° C. under nitrogen for 10 h. The reaction was stopped, and 2-aminopyridine (188 g, 2 mol) and 20 g of p-toluenesulfonic acid as a catalyst were added and reacted at 150° C. while vacuuming off the generated water. After 10 h, the reaction was stopped, and 46 g of NaOH aqueous solution (solid content 10%) was added to neutralize the p-toluenesulfonic acid. Water was removed by rotary evaporation at 80° C., insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 8 containing a coordination group, the structural formula of which is as follows:

[0099] Preparation Example 9

[0100] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 159 g of acrylonitrile (AN, 3 mol), 64 g of butyl acrylate (BA, 0.5 mol) and 195 g of hydroxyethyl methacrylate (HEMA, 1.5 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:300:50:150. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 128 g of cyanoacetic acid (1.5 mol), 12 g of catalyst 4-dimethylaminopyridine (DMAP) and 100 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 9 containing a coordination group, the structural formula of which is as follows:

[0101] Preparation Example 10

[0102] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 26 g of 2-picolinic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 10 containing a coordination group, the structural formula of which is as follows:

[0103] Preparation Example 11

[0104] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 22.6 g of oxazole-5-carboxylic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 11 containing a coordination group, the structural formula of which is as follows:

[0105] Preparation Example 12

[0106] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 28.6 g of 2-methylthiazole-5-carboxylic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 12 containing a coordination group. The structural formula is as follows:

[0107] Preparation Example 13

[0108] 1. Add 16.4 g of azobisisobutyronitrile (AIBN, 0.1 mol), 228 g of ethyl methacrylate (EMA, 2 mol), 216 g of acrylic acid (AA, 3 mol) and 610 g of allyl sulfonic acid (ASA, 5 mol) to a reactor. The molar ratio of AIBN, tBA, AA and ASA is 1:20:30:50. Then add 1.2 kg of N-methylpyrrolidone (NMP) as a solvent. React at 70 ° C under nitrogen protection for 10 hours, and then stop the reaction.

[0109] 2. Add 186g of boric acid (3mol) and 270g of oxalic acid (3mol) to a flask with a molar ratio of boric acid to oxalic acid of 1:1. Then add 1kg of NMP as a solvent and react at 100°C while vacuuming to remove the water produced by the reaction. Stop the reaction after 12 hours and test the solid content.

[0110] 3. The NMP solution of the product synthesized in step (2) (116 g of solid product) was added to the polymer solution in step (1), with the molar ratio of the product in step (2) to the polymer in step (1) being 30:1. The reaction was carried out at 100° C., and the water produced by the reaction was continuously removed by vacuum. The reaction was stopped after 12 h, and 150 g of lithium carbonate was added. The reaction was stirred at room temperature for 5 h, and the excess lithium carbonate was filtered off. The filtrate was collected and vacuum dried to obtain a polyolefin 13 containing a coordination group, the structural formula of which is as follows:

[0111] Preparation Example 14

[0112] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 27.4 g of 5-cyano-furan-2-carboxylic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 14 containing a coordination group, the structural formula of which is as follows:

[0113] Preparation Example 15

[0114] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 30.6 g of 5-cyanothiophene-2-carboxylic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 15 containing a coordination group. The structural formula is as follows:

[0115] Preparation Example 16

[0116] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:80:20:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 30.6 g of 5-cyanothiazole-2-carboxylic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 16 containing a coordination group. The structural formula is as follows:

[0117] Preparation Example 17

[0118] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol) and 25 g of ethyl cyanoacrylate (ECA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN and ECA of 1:80:20. 0.12 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped and the mixture was dried under vacuum to obtain polyolefin 17 containing a coordination group. The structural formula is as follows:

[0119] Preparation Example 18

[0120] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 42 g of acrylonitrile (AN, 0.8 mol), 26 g of butyl acrylate (BA, 0.2 mol) and 8.6 g of methacrylic acid (MAA, 0.1 mol) were added to a reactor in a molar ratio of AIBN, AN, BA to MAA of 1:80:20:10. 0.2 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70° C. under nitrogen for 10 h. The reaction was stopped, and 30 g of a LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups. The mixture was then vacuum dried to obtain polyolefin 18 containing a coordination group, the structural formula of which is as follows:

[0121] Preparation Example 19

[0122] 8.2 g of azobisisobutyronitrile (AIBN, 0.05 mol), 100 g of methyl methacrylate (MMA, 1 mol) and 72 g of acrylic acid (AA, 1 mol) were added to a reactor in a molar ratio of AIBN, MMA and AA of 1:20:20. 0.3 kg of N-methylpyrrolidone (NMP) was added as a solvent. The mixture was reacted at 70° C. under nitrogen protection for 10 h. The reaction was stopped, and 300 g of LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups. The mixture was vacuum dried to obtain polyolefin 19 containing a coordination group, the structural formula of which is as follows:

[0123] Preparation Example 20

[0124] 8.2 g of azobisisobutyronitrile (AIBN, 0.05 mol), 183 g of allylsulfonic acid (ASA, 1.5 mol), 98 g of N,N-dimethylacrylamide (DMAA, 1 mol) and 263 g of 4-vinylpyridine (VP, 2.5 mol) were added to a reactor in a molar ratio of AIBN, ASA, DMAA and VP of 1:30:20:50. 0.8 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped and the mixture was dried under vacuum to obtain polyolefin 20 containing a coordination group, the structural formula of which is as follows:

[0125] Preparation Example 21

[0126] 3.3 g of azobisisobutyronitrile (AIBN, 0.02 mol), 60 g of methyl methacrylate (MMA, 0.6 mol) and 106 g of 2-vinylpyrazine (1 mol) were added to a reactor in a molar ratio of AIBN, MMA and 2-vinylpyrazine of 1:30:50. 0.3 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped and the mixture was dried under vacuum to obtain polyolefin 21 containing a coordination group, the structural formula of which is as follows:

[0127] Preparation Example 22

[0128] 1.7 g of azobisisobutyronitrile (AIBN, 0.01 mol), 27 g of acrylonitrile (AN, 0.5 mol), 102 g of butyl acrylate (BA, 0.8 mol) and 26 g of hydroxyethyl methacrylate (HEMA, 0.2 mol) were added to a reactor in a molar ratio of AIBN, AN, BA and HEMA of 1:50:80:20. 0.5 kg of N-methylpyrrolidone (NMP) was added as a solvent and the mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped, and 26 g of 2-picolinic acid (0.2 mol), 6 g of catalyst 4-dimethylaminopyridine (DMAP) and 42 g of dehydrating agent N,N'-dicyclohexylcarbodiimide (DCC) were added and the mixture was reacted at 80°C for 10 h. The reaction was stopped after 10 h. The insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain polyolefin 22 containing a coordination group. The structural formula is as follows:

[0129] Preparation Example 23

[0130] 16.4 g of azobisisobutyronitrile (AIBN, 0.1 mol) and 315 g of 4-vinylpyridine (VP, 3 mol) were added to a reactor with a molar ratio of AIBN to VP of 1:30. 0.6 kg of N-methylpyrrolidone (NMP) was then added as a solvent. The mixture was reacted at 70°C under nitrogen for 10 h. The reaction was stopped and the mixture was dried under vacuum to obtain polyolefin 23 containing a coordination group. The structural formula is as follows:

[0131] Preparation Example 24

[0132] 354 g of succinic acid (3 mol) and 233 g of ethylene glycol (3.75 mol) were added to a reactor at a molar ratio of succinic acid to ethylene glycol of 1:1.25. 5 g of p-toluenesulfonic acid was then added as a catalyst, the mixture was vacuumed, and the reaction was continued at 160° C. for 10 h. 185 g of 2-pyridinecarboxylic acid (PA, 1.5 mol) was added, and the reaction was continued at 160° C. for 8 h. After the reaction was stopped, N,N-dimethylformamide (DMF) was added to dissolve the mixture, and 4 g of a NaOH aqueous solution (solid content 30%) was added to neutralize the p-toluenesulfonic acid. Water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, the filtrate was collected, and vacuum dried to obtain the final product, polyester 1 containing a coordination group, with the following structural formula:

[0133] Preparation Example 25

[0134] 50.8 g of dried pyromellitic acid (0.2 mol) and 240 g of δ-valerolactone monomer (1.2 mol) were added to a reactor, followed by 300 g of solvent N,N-dimethylformamide (DMF) and 2 g of catalyst sulfuric acid. The mixture was reacted at 110° C. for 12 h, 76 g of 2-hydroxypyridine (0.8 mol) was added, the temperature was raised to 120° C., and the reaction was continued for 6 h. The reaction was stopped, and 6.5 g of NaOH aqueous solution (solid content 25%) was added to neutralize the sulfuric acid. Water was removed by rotary evaporation at 80° C., insoluble matter was filtered off, the filtrate was collected, and vacuum dried to obtain the final product, polyester 2 containing a coordination group, with the following structural formula:

[0135] Preparation Example 26

[0136] 401 g of pyridine-2,6-dicarboxylic acid (2.4 mol) and 124 g of ethylene glycol (2 mol) were added to a reactor at a molar ratio of pyridine-2,6-dicarboxylic acid to ethylene glycol of 1.2:1. 600 g of solvent N-methylpyrrolidone (NMP) and 5 g of catalyst p-toluenesulfonic acid were then added. The reaction was vacuumed and allowed to react at 160° C. for 10 h. The reaction was stopped and 250 g of LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups and p-toluenesulfonic acid. Water was removed by rotary evaporation at 80° C., insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain the final product, polyester 3 containing a coordination group, with the following structural formula:

[0137] Preparation Example 27

[0138] 295 g of succinic acid (2.5 mol) and 124 g of ethylene glycol (2 mol) were added to a reactor at a molar ratio of succinic acid to ethylene glycol of 1.25:1. 5 g of p-toluenesulfonic acid was added as a catalyst, the reaction was carried out under vacuum, and the mixture was reacted at 160° C. for 10 h. 55 g of 4,6-diaminopyrimidine (0.5 mol) was added, and the reaction was continued at 160° C. for 8 h. After the reaction was stopped, N-methylpyrrolidone (NMP) was added to dissolve the mixture, and 6 g of a NaOH aqueous solution (solid content 20%) was added to neutralize the p-toluenesulfonic acid. The mixture was subjected to rotary evaporation at 80° C. to remove water, and the insoluble matter was filtered off. The filtrate was collected and dried under vacuum to obtain the final product, polyester 4 containing a coordination group, with the following structural formula, where n is an integer ≥1:

[0139] Preparation Example 28

[0140] 347 g of oxalic acid (3.75 mol) and 186 g of ethylene glycol (3 mol) were added to a reactor at a molar ratio of oxalic acid to ethylene glycol of 1.25:1. 3 g of p-toluenesulfonic acid was then added as a catalyst. The reaction was carried out under vacuum and allowed to react at 160° C. for 10 h. After the reaction was stopped, acetonitrile was added to dissolve the mixture. A LiOH aqueous solution was then added to adjust the pH to 7.0. The mixture was dried under vacuum. The final product obtained was polyester 5 containing a coordination group, with the structural formula as follows:

[0141] Preparation Example 29

[0142] 390 g of 2,5-furandicarboxylic acid (2.5 mol) and 124 g of ethylene glycol (2 mol) were added to a reactor at a molar ratio of 1.25:1. 200 g of N-methylpyrrolidone (NMP) and 5 g of tetrabutyl titanate were added as a catalyst. The reaction was carried out under vacuum at 170° C. for 10 h. The reaction was stopped, and 300 g of a LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups. Water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain the final product, polyester 6 containing a coordination group, with the following structural formula:

[0143] Preparation Example 30

[0144] 388 g of 1H-pyrrole-2,5-dicarboxylic acid (2.5 mol) and 124 g of ethylene glycol (2 mol) were added to a reactor with a molar ratio of 2,5-furandicarboxylic acid to ethylene glycol of 1.25:1. 200 g of solvent N-methylpyrrolidone (NMP) and 5 g of catalyst tetrabutyl titanate were then added. The mixture was vacuumed and reacted at 170° C. for 10 h. The reaction was stopped and 300 g of LiOH aqueous solution (solid content 8%) was added to neutralize the carboxyl groups. Water was removed by rotary evaporation at 80° C., insoluble matter was filtered off, and the filtrate was collected and dried under vacuum to obtain the final product, polyester 7 containing a coordination group, with the following structural formula:

[0145] Preparation Example 31

[0146] 3.1 g of ethylene glycol (0.05 mol) and 285 g of ε-caprolactone (CL, 2.5 mol) were added to a reactor in a molar ratio of ethylene glycol to ε-caprolactone of 1:50. 2 g of methanesulfonic acid was added as a catalyst, and the mixture was reacted at 100° C. under vacuum for 12 h. After the reaction was stopped, N-methylpyrrolidone (NMP) was added for dissolution. 12.3 g of 2-pyridinecarboxylic acid (0.1 mol) was added, and the temperature was raised to 120° C. and the reaction was continued for 6 h. The reaction was stopped, and 6.5 g of NaOH aqueous solution (solid content 25%) was added to neutralize the sulfuric acid. Water was removed by rotary evaporation at 80° C., the insoluble matter was filtered off, the filtrate was collected, and vacuum dried to obtain the final product, polyester 8 containing a coordination group, with the following structural formula:

[0147] Preparation Example 32

[0148] 278 g of hexamethylenediamine (2.4 mol) and 332 g of terephthalic acid (2 mol) were added to a reactor with a molar ratio of hexamethylenediamine to terephthalic acid of 1.2:1. The mixture was reacted at 250°C under vacuum for 12 h. After stopping the reaction, 2 kg of N-methylpyrrolidone (NMP) was added for dissolution. 60 g of 2,3-pyridinedicarboxylic anhydride (0.4 mol) was then added and reacted at room temperature for 48 h. The mixture was then transferred to a vacuum oven for a gradual temperature increase reaction at 160°C for 1 h, 200°C for 30 min, and 230°C for 30 min. The mixture was then vacuumed to obtain a final product, polyamide 1 containing a coordination group, having the following structural formula:

[0149] Preparation Example 33

[0150] 161 g of adipic acid (1.1 mol) and 109 g of 2,6-diaminopyridine (1 mol) were added to a reactor with a molar ratio of adipic acid to 2,6-diaminopyridine of 1.1:1. The mixture was reacted at 250°C under vacuum for 12 h. 19 g of 2-hydroxypyridine (0.2 mol) and 5 g of sulfuric acid were then added. The reaction was continued at 100°C under vacuum for 6 h. After the reaction was stopped, N-methylpyrrolidone (NMP) was added to dissolve the mixture. 20 g of a NaOH aqueous solution (solid content 20%) was then added to neutralize the sulfuric acid. Water was removed by rotary evaporation at 80°C, insoluble matter was filtered off, the filtrate was collected, and vacuum dried to obtain the final product, polyamide 2 containing a coordination group, with the following structural formula:

[0151] Preparation Example 34

[0152] 183 g of adipic acid (1.25 mol) and 200 g of 4,4'-diaminodiphenyl ether (1 mol) were added to a reactor with a molar ratio of adipic acid to 4,4'-diaminodiphenyl ether of 1.25:1. The mixture was reacted at 250° C. under vacuum for 12 h. 55 g of 3-hydroxyglutaronitrile (0.5 mol) and 5 g of sulfuric acid were then added. The reaction was continued at 100° C. under vacuum for 6 h. After the reaction was stopped, N-methylpyrrolidone (NMP) was added to dissolve the mixture. 20 g of a NaOH aqueous solution (solid content 20%) was then added to neutralize the sulfuric acid. Water was removed by rotary evaporation at 80° C., insoluble matter was filtered off, the filtrate was collected, and vacuum dried to obtain the final product, polyamide 3 containing a coordination group, with the following structural formula:

[0153] Preparation Example 35

[0154] 245 g of pentamethylenediamine (2.4 mol), 312 g of 2,5-furandicarboxylic acid (2 mol) and 5 g of p-toluenesulfonic acid were added to a reactor with a molar ratio of pentamethylenediamine to 2,5-furandicarboxylic acid of 1.2:1. The mixture was reacted at 200°C under vacuum for 12 h. 45 g of furoic acid (0.4 mol) was then added and the reaction was continued at 200°C for 5 h. The reaction was stopped and the product was dissolved in N-methylpyrrolidone (NMP) and precipitated in a large amount of dimethyl carbonate (DMC). The solid was collected and dried under vacuum to obtain a final product, polyamide 4 containing a coordination group, with the following structural formula:

[0155] Preparation Example 36

[0156] 245 g of pentamethylenediamine (2.4 mol), 344 g of 2,5-thiophenedicarboxylic acid (2 mol) and 5 g of p-toluenesulfonic acid were added to a reactor with a molar ratio of pentamethylenediamine to 2,5-thiophenedicarboxylic acid of 1.2:1. The mixture was reacted at 200°C under vacuum for 12 h. 51 g of thiophene-2-carboxylic acid (0.4 mol) was then added and the reaction was continued at 200°C for 5 h. The reaction was stopped and the product was dissolved in N-methylpyrrolidone (NMP) and precipitated in a large amount of dimethyl carbonate (DMC). The solid was collected and dried under vacuum to obtain a final product, polyamide 5 containing a coordination group, with the following structural formula:

[0157] Preparation Example 37

[0158] 167 g of pyridine-2,6-dicarboxylic acid (1 mol) and 74 g of ethylene glycol (1.2 mol) were added to a reactor at a molar ratio of 1:1.2. 100 g of solvent N-methylpyrrolidone (NMP) and 1 g of catalyst tetrabutyl titanate were then added. The mixture was vacuumed and reacted at 160°C for 10 h. The reaction was stopped. 35 g of toluene-2,4-diisocyanate (TDI, 0.2 mol) was then added at a molar ratio of 5:1 of pyridine-2,6-dicarboxylic acid to TDI. The reaction was continued at 60°C for 8 h. The reaction was stopped and the mixture was vacuumed and dried. The final product was polyurethane 1 containing a coordination group, with the following structural formula, where n is an integer ≥1:

[0159] Preparation Example 38

[0160] To a reactor, 310 g of 4,4'-diphenyl ether dianhydride (ODPA, 1 mol) and 361 g of benzidine disulfonic acid (BDSA, 1.05 mol) were added at a molar ratio of 1:1.05. 1.5 kg of N-methylpyrrolidone (NMP) was added as solvent and the mixture was stirred at room temperature for 48 hours. 15 g of 2,3-pyrazine dianhydride (0.1 mol) was then added and the mixture was stirred at room temperature for another 24 hours. The reaction mixture was transferred to a vacuum oven and the temperature was gradually increased to 160°C for 1 hour and 250°C for 1 hour. The mixture was then evacuated to obtain the final product, polyimide 1, containing a coordinating group, with the following structural formula:

[0161] The basic properties of the polymer prepared above were tested using the following method, and the test results are shown in Table 1.

[0162] (1) Molecular weight determination:

[0163] The absolute molecular weight of the polymer was determined by gel permeation chromatography-laser light scattering (GPC-MALLS) using a 1515GPC gel chromatograph from Waters, USA, and a DAWN HELEOS-II light scattering detector from Wyatt, USA.

[0164] (2) Determination of swelling degree:

[0165] The above polymer was made into a circular film with a thickness of 30μm and a size of 16mm*16mm. The mass of the film was weighed and the film was immersed in 10g of electrolyte. After sealing, it was stored at 45℃. The film was taken out every 8 hours, the electrolyte on the surface was wiped off, the thickness was measured and weighed, and then it was put back into the electrolyte and sealed and continued to be stored at 45℃. If the thickness and mass of the film remain unchanged after three consecutive tests, it is considered that the polymer film has reached a swelling equilibrium state. The swelling degree is calculated according to the following formula: the difference in mass before and after immersion in electrolyte / the mass of the film before immersion * 100% is the swelling degree of the polymer.

[0166] In the above formula, m0 represents the mass of the polymer membrane before immersion in the electrolyte, and m1 represents the mass of the polymer membrane when the swelling equilibrium is reached after immersion in the electrolyte.

[0167] The electrolyte was prepared as follows: lithium hexafluorophosphate (LiPF6) was dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC was 3:7) in a glove box with a dew point below -40°C to prepare an electrolyte with a LiPF6 concentration of 1.2 mol / L. Then, 1.5% of the weight of the entire electrolyte, vinylene carbonate (VC) and 1% of 1,3-propane sultone (1,3-PS) were added to obtain the required electrolyte.

[0168] (3) Determination of swelling loss rate

[0169] The above polymer was made into a circular film with a thickness of 30 μm and a size of 16 mm * 16 mm. The mass of the film was weighed and the film was immersed in 10 g of electrolyte. After sealing, it was stored at 45 ° C. The film was taken out every 8 hours, the electrolyte on the surface was wiped off, the thickness was measured and weighed, and then it was returned to the electrolyte and sealed and continued to be stored at 45 ° C until the thickness and mass of the film remained unchanged after three consecutive tests. The excess electrolyte and lithium salt on the film were rinsed with solvent dimethyl carbonate (DMC) and completely dried in an oven. The mass of the remaining film after drying was weighed, and the swelling loss rate was calculated according to the following formula:

[0170] In the above formula, m0 represents the mass of the polymer membrane before soaking in the electrolyte, and the unit is g; m2 represents the mass of the polymer membrane remaining after soaking in the electrolyte and then washing and drying, and the unit is g.

[0171] The electrolyte was prepared as follows: lithium hexafluorophosphate (LiPF6) was dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC was 3:7) in a glove box with a dew point below -40°C to prepare an electrolyte with a LiPF6 concentration of 1.2 mol / L. Then, 1.5% of the weight of the entire electrolyte, vinylene carbonate (VC) and 1% of 1,3-propane sultone (1,3-PS) were added to obtain the required electrolyte.

[0172] Example 1

[0173] 1. Battery production

[0174] 1.1 Preparation of positive electrode plate

[0175] The positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, carbon black conductive agent PVDF binder The positive electrode active material, carbon black conductive agent and binder were mixed in a double planetary mixer at a weight ratio of 96.5:1.5:2. The total weight of the positive electrode active material, carbon black conductive agent and binder was 1 kg. 0.5 kg of N-methylpyrrolidone (NMP) was added and stirred thoroughly. Then, the NMP solution of polyolefin 1 prepared in Preparation Example 1 (solid content 20%) was added. The amount of polyolefin 1 added was 1% based on the total weight of the positive electrode coating material solids. After further stirring, the mixture was filtered through a filter to obtain a positive electrode material slurry with a solid content of 65%. The slurry was then applied to both sides of an aluminum foil with a thickness of 12 μm using an extrusion coater. After baking and hot rolling, a positive electrode plate was obtained. The surface density of the coating on one side of the positive electrode plate was 20 mg / cm 2 .

[0176] 1.2 Preparation of negative plate

[0177] The negative electrode active material artificial graphite, carbon black conductive agent Sodium carboxymethyl cellulose (CMC) was mixed in a weight ratio of 97:1.5:1.5 and then placed in a double planetary mixer. The total weight of the negative electrode active material, carbon black conductive agent, and sodium carboxymethyl cellulose was 1 kg. 0.8 kg of deionized water (DIW) was added and stirred thoroughly. Then, styrene-butadiene rubber emulsion (SBR) with a solid content of 50% and accounting for 1% of the total solid weight of the negative electrode material was added. After further stirring, the mixture was filtered through a filter to obtain a negative electrode material slurry with a solid content of 45%. The slurry was then applied to both sides of a 6 μm thick copper foil using an extrusion coater. After baking and hot roller pressing, the negative electrode plate was obtained. The surface density of the coating on one side of the negative electrode plate was 13 mg / cm 2 .

[0178] 1.3 Preparation of dry cells

[0179] The above-mentioned positive electrode plate, the above-mentioned negative electrode plate, and a commercially available PE separator with boehmite coating on both sides are cut into a certain shape, wherein the size of the active material area on the positive electrode plate is 48mm×44mm, the size of the active material area on the negative electrode plate is 52mm×46mm, the size of the separator is 56mm×50mm, and a current collector lead-out portion is left on the positive electrode plate and the negative electrode plate respectively; then, they are stacked layer by layer in the order of negative electrode plate, separator, positive electrode plate, separator, negative electrode plate, ..., for a total of 18 positive electrode plates and 19 negative electrode plates, with the outermost layer being the negative electrode plate; then, the current collector lead-out portions of the positive electrode plates are welded together with an ultrasonic welder, and the positive electrode tabs are welded on; the current collector lead-out portions of the negative electrode plates are welded together with an ultrasonic welder, and the negative electrode tabs are welded on, thereby obtaining a laminated body.

[0180] The above-mentioned laminated body is placed in a packaging bag made of two pieces of aluminum-plastic film after shelling, and the hot melt adhesive on the tab is welded to the packaging bag by hot melting. The tab is led out of the packaging bag, and an air bag and a liquid injection port are left on one side of the packaging bag to obtain a dry battery cell.

[0181] 1.4 Preparation of electrolyte

[0182] In a glove box with a dew point below -40°C, lithium hexafluorophosphate (LiPF6) was dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (the volume ratio of EC to EMC was 3:7) to prepare an electrolyte with a LiPF6 concentration of 1.2 mol / L. Then, 1.5% of vinylene carbonate (VC) and 1% of 1,3-propane sultone (1,3-PS) were added to the electrolyte to obtain the required electrolyte.

[0183] 1.5 Preparation of batteries

[0184] In a glove box maintained at a dew point below -40°C, the electrolyte was injected into the dry cell through the injection port. After 24 hours, the injection port on the outside of the airbag was sealed using a vacuum heat sealer, and the gas in the cell was simultaneously extracted. This yielded an unformed cell. The unformed cell was weighed and the weight of the dry cell was subtracted to obtain the weight of the injected electrolyte.

[0185] 1.6 Battery Formation

[0186] The battery cell is formed using a charging and discharging device. First, it is charged to 3.6V at a constant current of 0.05C. Then, it is sealed by vacuum exhausting with a vacuum heat sealer and the airbag is cut off. Then, it is charged to 4.2V at a constant current of 0.2C. Then, it is charged at a constant voltage until the current drops to 0.05C. Then, it is discharged to 3.0V at a constant current of 0.2C. Thus, a formed battery cell is obtained, which is the gel electrolyte lithium ion battery of the present invention.

[0187] 2. Battery testing

[0188] 2.1 First discharge capacity test

[0189] At room temperature, the formed batteries were charged at a constant current of 1C to 4.2V, then charged at a constant voltage until the current dropped to 0.05C. They were then discharged at a constant current of 1C to 3.0V to obtain the initial discharge capacity (Ah). Some batteries were then subjected to high-temperature storage testing, while others were subjected to charge-discharge cycle testing.

[0190] 2.2 Internal resistance test

[0191] Charge the battery to a half-charged state, connect the test fixture to the internal resistance tester, and clamp the positive and negative poles of the battery respectively. Test the AC impedance of the battery at 1KHz, which is the internal resistance of the battery.

[0192] 2.3 High temperature storage test

[0193] The battery was charged at room temperature at a constant current of 1C to 4.2V, and then charged at a constant voltage until the current dropped to 0.05C. The battery was then transferred to a 60°C oven and stored for 7 days. The thickness of the test battery was taken out and the thickness expansion rate was calculated by comparing it 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%;

[0194] After the battery cools to room temperature, discharge it at a constant current of 1C to 3.0V. The obtained discharge capacity is compared with the discharge capacity before high-temperature storage to calculate the capacity retention rate, that is, capacity retention rate = discharge capacity after high-temperature storage / discharge capacity before high-temperature storage * 100%;

[0195] The battery was then charged to 4.2V at a constant current of 1C, then charged at a constant voltage until the current dropped to 0.05C, and then discharged to 3.0V at a constant current of 1C. The resulting discharge capacity was compared with the discharge capacity before high-temperature storage to obtain the capacity recovery rate, i.e., capacity recovery rate = discharge capacity after high-temperature storage after charging and discharging again / discharge capacity before high-temperature storage * 100%.

[0196] 2.4 Charge and discharge cycle test

[0197] The battery was charged to 4.2V at a constant current of 1C at room temperature (25°C) and high temperature (45°C), then charged at a constant voltage until the current dropped to 0.05C, and then discharged to 3.0V at a constant current of 1C. This cycle was repeated for 1000 cycles, and the discharge capacity retention rate was calculated by comparing the last discharge capacity with the first discharge capacity.

[0198] 2.5 Hot box test

[0199] Conduct a battery heating experiment according to GB / T 31485-2015. Place the battery in a temperature chamber and raise the temperature from room temperature to 130°C ± 2°C at a rate of 5°C / min. Maintain this temperature for 30 minutes. If the battery is normal, heat it by 5°C for 30 minutes and observe whether the battery is abnormal. For example, continue heating to 135°C and hold it for 30 minutes, then to 140°C and hold it for 30 minutes, then to 145°C and hold it for 30 minutes, etc., until the battery smokes or burns. Record this temperature, which is the thermal runaway temperature.

[0200] The above test results are shown in Table 2.

[0201] Example 2

[0202] Compared with Example 1, during the production of the positive electrode plate, polyolefin 2 prepared in Preparation Example 2 was used instead of polyolefin 1, and its addition amount accounted for 0.5% of the total weight of the solid content of the positive electrode coating material. Other conditions were the same as in Example 1.

[0203] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0204] Example 3

[0205] Compared with Example 1, during the production of the positive electrode plate, polyolefin 3 prepared in Preparation Example 3 was used instead of polyolefin 1, and its addition amount accounted for 2% of the total weight of the solid content of the positive electrode coating material. Other conditions were the same as in Example 1.

[0206] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0207] Example 4

[0208] Compared with Example 1, during the production of the positive electrode plate, polyester 1 prepared in Preparation Example 24 was used instead of polyolefin 1, and its addition amount accounted for 1.5% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0209] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0210] Example 5

[0211] Compared with Example 1, during the production of the positive electrode plate, polyester 2 prepared in Preparation Example 25 was used to replace polyolefin 1, and its addition amount was 3% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0212] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0213] Example 6

[0214] Compared with Example 1, during the production of the positive electrode plate, polyamide 1 prepared in Preparation Example 32 was used instead of polyolefin 1, and its addition amount was 0.1% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0215] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0216] Example 7

[0217] Compared with Example 1, during the production of the positive electrode plate, polyurethane 1 prepared in Preparation Example 37 was used to replace polyolefin 1, and its addition amount accounted for 0.8% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0218] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0219] Example 8

[0220] Compared with Example 1, during the production of the positive electrode plate, polyimide 1 prepared in Preparation Example 38 was used instead of polyolefin 1, and its addition amount was 1% of the total weight of the solid content of the positive electrode coating material. Other conditions were the same as in Example 1.

[0221] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0222] Example 9

[0223] Compared with Example 1, during the production of the positive electrode plate, polyolefin 10 prepared in Preparation Example 10 was used instead of polyolefin 1, and its addition amount accounted for 2% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0224] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0225] Example 10

[0226] Compared with Example 1, during the production of the positive electrode plate, polyamide 2 prepared in Preparation Example 33 was used instead of polyolefin 1, and its addition amount accounted for 4% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0227] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0228] Example 11

[0229] Compared with Example 1, during the production of the positive electrode plate, polyolefin 13 prepared in Preparation Example 13 was used instead of polyolefin 1. The added amount was 1% of the total weight of the solid content of the positive electrode coating material. Other steps were the same as in Example 1.

[0230] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0231] Example 12

[0232] Compared with Example 1, during the production of the positive electrode plate, polyester 3 prepared in Preparation Example 26 was used to replace polyolefin 1, and its addition amount was 2% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0233] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0234] Example 13

[0235] Compared with Example 1, during the production of the positive electrode plate, polyester 6 prepared in Preparation Example 29 was used to replace polyolefin 1, and its addition amount was 1% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0236] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0237] Example 14

[0238] Compared with Example 1, during the production of the positive electrode plate, polyolefin 11 prepared in Preparation Example 11 was used instead of polyolefin 1, and its addition amount accounted for 0.8% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0239] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0240] Example 15

[0241] Compared with Example 1, during the production of the positive electrode plate, polyester 7 prepared in Preparation Example 30 was used instead of polyolefin 1, and its addition amount accounted for 1.2% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0242] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0243] Example 16

[0244] Compared with Example 1, during the production of the positive electrode plate, polyolefin 18 prepared in Preparation Example 18 was used instead of polyolefin 1, and its addition amount accounted for 3% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0245] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0246] Example 17

[0247] Compared with Example 1, during the production of the positive electrode plate, polyolefin 20 prepared in Preparation Example 20 was used to replace polyolefin 1, and its addition amount was 2% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

[0248] The battery was tested according to the test method of Example 1, and the test results are shown in Table 2.

[0249] Example 18

[0250] Compared with Example 1, during the production of the positive electrode plate, polyimide 1 prepared in Preparation Example 38 was used instead of polyolefin 1, and its addition amount was 0.05% of the total weight of the solid matter of the positive electrode coating material. Other conditions were the same as in Example 1.

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

[0252] Example 19

[0253] Compared with Example 1, during the production of the positive electrode plate, polyamide 2 prepared in Preparation Example 33 was used instead of polyolefin 1, and its addition amount accounted for 6% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

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

[0255] Comparative Example 1

[0256] Except that polyolefin 1 is not added during the production of the positive electrode plate, other aspects are the same as those of Example 1.

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

[0258] Comparative Example 2

[0259] Compared with Example 1, during the production of the positive electrode plate, polyolefin 23 prepared in Preparation Example 23 was used instead of polyolefin 1, and its addition amount accounted for 2% of the total weight of the solid content of the positive electrode coating material. Other conditions were the same as in Example 1.

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

[0261] Comparative Example 3

[0262] Compared with Example 1, during the production of the positive electrode plate, polyolefin 22 prepared in Preparation Example 22 was used to replace polyolefin 1, and its addition amount was 1% of the total weight of the solid content of the positive electrode coating material. Other conditions were the same as in Example 1.

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

[0264] Comparative Example 4

[0265] Compared with Example 1, during the production of the positive electrode plate, polyester 8 prepared in Preparation Example 31 was used instead of polyolefin 1, and its addition amount accounted for 2% of the total weight of the solid content of the positive electrode coating material. Other factors were the same as in Example 1.

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

[0267] Table 1 Basic parameters for preparing polymers Note: The swelling degree of polyester 8 is “-”, which means that the polymer dissolves during the test.

[0268] Table 2. Battery performance test results

[0269] As can be seen from Table 1, the polymers containing coordination groups used in Examples 1-15 are selected from polymers having one of the structures of Formula 1-Formula 23. The coordination groups in the above polymers are multidentate ligands, which can have a strong coordination effect with the transition metal ions in the positive electrode active material, and the protective layer formed is more stable. The polymers containing coordination groups used in Examples 16-17 can also have a coordination effect with the transition metal ions in the positive electrode active material due to the long distance between the coordination groups or the steric hindrance, but the coordination effect is weaker than that of the polymers having the structures of Formula 1-Formula 23. Moreover, under the condition of 45°C, the swelling degree of these polymers in the electrolyte is between 5% and 50%, and the swelling loss rate is less than 2%.

[0270] As shown in Table 2, compared with Comparative Example 1, which does not include the polymer containing a coordinating group of the present invention, the lithium-ion batteries obtained by adding the polymer containing a coordinating group to the positive electrode coating material in Examples 1-19 all showed significant improvements in initial performance, high-temperature storage, and cycle performance. The lithium-ion batteries obtained in Examples 1-15 had a capacity of approximately 3 Ah, an internal resistance of 6.8-8.9 mΩ, a high-temperature storage thickness expansion rate of 0.2-2.2%, a high-temperature storage capacity retention rate of 96.3-98.1%, a high-temperature storage capacity recovery rate of 97.2-98.9%, a room-temperature cycle capacity retention rate of 92.1-93.8% after 1000 cycles, and a high-temperature cycle capacity retention rate of 88.7-90.8%. Furthermore, the thermal runaway temperature in the hot box test was also 165-180°C. The initial performance, high-temperature storage, and cycle performance of the lithium-ion batteries obtained in Examples 16-17 were inferior to those in Examples 1-15, and the thermal runaway temperature was also slightly lower at 155°C. Compared with Example 8, Example 18 added only 0.05% of polyimide 1 to the positive electrode coating material, and the high-temperature performance, cycle performance, and safety performance of the lithium-ion battery prepared therefrom deteriorated, but were better than those of Comparative Examples 1 and 2. Compared with Example 10, Example 19 added 6% of polyimide 2, and the internal resistance of the battery was significantly increased.

[0271] The positive electrode coating of Comparative Example 1 does not contain the polymer containing the coordination group of the present invention. The initial performance of the lithium-ion battery prepared therefrom is good, but the high-temperature storage and cycle performance are poor. The capacity retention rate is less than 80% after 1000 cycles of high-temperature cycling, and the thermal runaway temperature is 140°C.

[0272] In comparative example 2, polyolefin 23 with a swelling degree of only 2% was added, resulting in a significant increase in the internal resistance of the battery and a low capacity. After 1000 cycles at room temperature, the capacity decayed to less than 80%.

[0273] Comparative Example 3 added polyolefin 22 with a swelling degree of 86%, and Comparative Example 4 added polyester 8 that can be dissolved in the electrolyte. Both groups of batteries showed low capacity. The high-temperature storage and cycle performance were slightly better than those of Comparative Example 1, but significantly lower than those of Examples 1-17, and the thermal runaway temperature did not increase at all.

[0274] In summary, the present invention adds a polymer containing a coordination group to the positive electrode, and the coordination group contained in the polymer coordinates with the transition metal ions of the positive electrode active material, so that the polymer can be adsorbed on the surface of the positive electrode active material. At the same time, the polymer can absorb the electrolyte after contact with the electrolyte to cause low swelling, thereby forming a complete and stable polymer coating layer with a certain ion-conducting effect on the surface of the positive electrode active material, which can more effectively inhibit the decomposition reaction of the electrolyte on the surface of the positive electrode active material. This technology can use the traditional production process, avoiding the problem of complex process and incomplete coating caused by inorganic coating of the positive electrode active material alone in the prior art, and can meet the needs of high energy density and high safety batteries. At the same time, this technology can also inhibit the oxidative decomposition reaction of the electrolyte on the surface of the positive electrode active material and the dissolution of transition metal ions, thereby greatly improving the high temperature performance of the lithium ion battery and improving the safety of the lithium ion battery, and has great application prospects.

[0275] In addition, the polymer containing a coordination group of the present invention is also suitable for sodium ion batteries. The coordination group contained in the polymer coordinates with the transition metal ions of the positive electrode active material of the sodium ion battery, and the polymer can be adsorbed on the surface of the positive electrode active material. At the same time, after the polymer comes into contact with the electrolyte, it can absorb the electrolyte and swell slightly, thereby forming a complete and stable polymer coating layer with a certain ion-conducting effect on the surface of the positive electrode active material, which can more effectively inhibit the decomposition reaction of the electrolyte on the surface of the positive electrode active material, ultimately improving the high-temperature performance of the sodium ion battery and improving the safety of the sodium ion battery.

[0276] Although the present application discloses the preferred embodiments as above, it is not intended to limit the claims. Any person skilled in the art can make a number of possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application. The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A lithium-ion battery or a sodium-ion battery, which comprises a positive electrode, a negative electrode, a separator and an electrolyte. The positive electrode comprises a current collector and a positive electrode coating material loaded on the current collector. The positive electrode coating material comprises a positive electrode active material containing a transition metal and a polymer containing a coordination group. The coordination group can coordinate with the transition metal ions in the positive electrode active material, and at 25-60 °C, the swelling degree of the polymer containing a coordination group in the electrolyte is 5-50%.

2. The lithium-ion battery or sodium-ion battery according to claim 1, wherein the coordination group contains one or more of cyano, carbonyl, pyridyl, pyrazinyl, pyrimidinyl, furyl, pyrrolyl, thienyl, thiazolyl and oxazolyl.

3. The lithium-ion battery or sodium-ion battery according to claim 1 or 2, wherein the coordination group contains two or more atoms capable of coordinating with the same transition metal ion.

4. The lithium-ion battery or sodium-ion battery according to any one of claims 1-3, wherein the coordination group includes one or more of the following structures, Among them, R1 is selected from one of 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. R2 and R4 are each independently selected from one of 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. R3 is selected from one of 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 is selected from S, NH or O. X2 is selected from S or O.

5. The lithium-ion battery or sodium-ion battery according to any one of claims 1-4, wherein the polymer containing a coordination group is selected from one or more of polyolefin, polyester, polyamide, polyurethane and polyimide.

6. The lithium-ion battery or sodium-ion battery according to any one of claims 1-5, based on the total weight of the solid matter of the positive electrode coating material loaded on the current collector, the content of the polymer containing a coordination group is 0.1-10%, preferably 0.2-5%, more preferably 0.2-2%, and further preferably 0.5-2%.

7. The lithium-ion battery or sodium-ion battery according to any one of claims 1-6, wherein the transition metal is selected from one or more of nickel, cobalt, manganese, copper and iron.

8. The lithium-ion battery or sodium-ion battery according to any one of claims 1-7, wherein the electrolyte comprises an organic solvent; Preferably, the organic solvent is selected from one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate and propyl propionate; More preferably, in the lithium battery, the electrolyte further comprises a lithium salt, and the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide; or, In the sodium battery, the electrolyte further comprises a sodium salt, and the sodium salt is selected from one or more of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium bis(trifluoromethylsulfonyl)imide and sodium bis(fluorosulfonyl)imide.

9. The lithium-ion battery or sodium-ion battery according to claim 8, wherein the electrolyte further comprises one or more of an unsaturated cyclic carbonate, a fluorinated cyclic carbonate, a cyclic sultone, and a cyclic sulfate ester; Preferably, the unsaturated cyclic carbonate is selected from vinylene carbonate and / or ethylene 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 ester is selected from at least one of ethylene sulfate, propylene sulfate, and 4-methyl ethylene sulfate.

10. A method for preparing the lithium-ion battery or sodium-ion battery according to any one of claims 1-9, the method comprising forming an electrode assembly by arranging a positive electrode, a negative electrode, and a separator in a battery housing, then injecting an electrolyte to obtain a semi-finished lithium-ion battery or a semi-finished sodium-ion battery, and forming and degassing the semi-finished lithium-ion battery or the semi-finished sodium-ion battery and then sealing the liquid injection port of the battery housing to obtain the lithium-ion battery or the sodium-ion battery, Among them, wherein the positive electrode is obtained by coating a positive electrode coating material on a current collector, followed by drying, rolling, and slitting, and the positive electrode coating material is prepared by mixing the polymer containing a coordination group with a solvent and then mixing with a positive electrode active material, a conductive agent, and a binder.

11. A positive electrode coating material, which comprises a positive electrode active material containing a transition metal and a polymer containing a coordination group; preferably, the positive electrode coating material further contains a conductive agent and a binder.

12. A method for preparing a positive electrode coating material, which comprises mixing the polymer containing a coordination group with a solvent and then mixing with a positive electrode active material, a conductive agent, and a binder.

Images