An additive, a method for manufacturing the same, a battery element, a battery, a battery pack, and an electric device

Abstract

The application provides an additive, a preparation method of the additive, a battery element, a battery, a battery pack and an electric device. The additive provided by the embodiment of the application comprises a base body and a crown ether group grafted on the base body; the specific surface area of the additive is 20 m 2 / g~600 m 2 / g, and the base body is electrochemically inert. The additive provided by the embodiment of the application can improve the mass transfer efficiency inside the battery and effectively adsorb metal impurities generated in the battery cycle process, and can effectively improve the service life of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an additive and its preparation method, battery elements, batteries, battery packs, and electrical devices. Background Technology

[0002] Due to their rechargeable and rechargeable characteristics, rechargeable batteries have significant advantages in terms of economy, environmental protection and convenience, and are widely used in portable electronic devices and new energy vehicles.

[0003] To improve the energy density of rechargeable batteries, their electrodes often have high compaction and areal density, which drastically reduces the battery's internal mass transfer efficiency, increases internal resistance, and shortens battery life. Furthermore, the positive electrode material in rechargeable batteries is highly susceptible to the dissolution of metallic impurities during cycling, leading to gas generation and further shortening battery life.

[0004] Therefore, how to effectively adsorb metallic impurities to improve battery life is a problem that urgently needs to be solved in the preparation of secondary batteries. Summary of the Invention

[0005] This invention provides an additive and its preparation method, a battery element, a battery, a battery pack, and an electrical device. The additive of this invention can improve the internal mass transfer efficiency of the battery and effectively adsorb metal impurities generated during battery cycling, thereby effectively improving the battery life.

[0006] This invention provides an additive comprising a matrix and a crown ether group grafted onto the matrix;

[0007] The specific surface area of ​​the additive is 20 m². 2 / g ~600 m 2 / g;

[0008] The matrix is ​​electrochemically inert.

[0009] In some embodiments of the present invention, the Dv50 of the additive is 100nm~800nm;

[0010] And / or, the grafting rate of the crown ether group on the matrix is ​​0.0001% to 50%; preferably 5% to 30%.

[0011] In some embodiments of the present invention, the matrix includes at least one of a metal oxide matrix, a non-metal oxide matrix, and a metal phosphide matrix.

[0012] In some embodiments of the present invention, the matrix comprises a metal oxide matrix, which includes one or more of aluminum oxide matrix, tin oxide matrix, cobalt oxide matrix, and titanium oxide matrix;

[0013] And / or, the matrix comprises a non-metallic oxide matrix, wherein the non-metallic oxide matrix comprises a silicon oxide matrix;

[0014] And / or, the matrix comprises a metal phosphide matrix, wherein the metal phosphide matrix comprises one or more of aluminum phosphate matrix and iron phosphate matrix;

[0015] And / or, the crown ether group includes one or more of 12-crown-4, 15-crown-5, 18-crown-6, 21-crown-7, 2.2.1-cryptoether, 2.2.2-cryptoether, azacrown ether group, thiocrown ether group, selenocrown ether group, dibenzo-12-crown-4, dibenzo-15-crown-5, dibenzo-18-crown-6, dibenzo-21-crown-7, dibenzo-24-crown-8, and carboxylic acid-18-crown-6.

[0016] Some embodiments of the present invention include a grafting group connecting the crown ether group to the matrix, wherein the grafting group includes at least one of amide, amino, and urea groups.

[0017] This invention also provides a method for preparing the additive as described above, comprising the following steps:

[0018] The additive is obtained by polymerizing the matrix precursor and the crown ether precursor.

[0019] The specific surface area of ​​the matrix precursor is 20 m². 2 / g ~600 m 2 / g.

[0020] In some embodiments of the present invention, the method for preparing the matrix precursor includes the following steps:

[0021] The matrix raw material is subjected to a first modification treatment using a first modifier to obtain the matrix precursor;

[0022] Wherein, the first modifier includes a first grafting reactive group; preferably, the first modifier includes one or more of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-(methacryloyloxy)propyltri(2-methoxyethoxy)silane.

[0023] In some embodiments of the present invention, the preparation method of the crown ether precursor includes the following steps:

[0024] The crown ether raw material is subjected to a second modification treatment using a second modifier to obtain the crown ether precursor;

[0025] The second modifier includes a second grafted reactive group; preferably, the second modifier includes one or more of carboxylic acid modifiers, acyl chloride modifiers, epoxy modifiers, and isocyanate modifiers.

[0026] In some embodiments of the present invention, the polymerization reaction includes: performing a condensation reaction between a second graft reactive group in the crown ether precursor and a first graft reactive group in the matrix precursor to obtain the additive;

[0027] Preferably, the polymerization reaction temperature is 20℃~30℃;

[0028] Preferably, the polymerization reaction takes place over a period of 12 to 60 hours.

[0029] This invention also provides a battery element comprising the additives described above, or additives prepared by the method described above.

[0030] In some embodiments of the present invention, the battery element includes a positive electrode, and the positive electrode includes the additive;

[0031] And / or, the battery element includes a negative electrode, the negative electrode including the additive;

[0032] And / or, the battery element includes a separator, the separator including the additive;

[0033] And / or, the battery element includes an electrolyte, the electrolyte including the additive, preferably the matrix of the additive being an alumina matrix.

[0034] In some embodiments of the present invention, the battery element includes an element substrate and a functional coating disposed on at least one side of the element substrate. The functional coating includes the additive, and the mass percentage of the additive in the functional coating is 0.001wt%-70wt%; preferably 1wt%-8wt%.

[0035] This invention also provides a battery, including the battery element described above.

[0036] This invention also provides a battery pack comprising at least two batteries as described above.

[0037] This invention also provides an electrical device, including the battery or battery pack described above.

[0038] The additives and their preparation methods, battery elements, batteries, battery packs, and electrical devices provided in this invention include a matrix and crown ether groups grafted onto the matrix, and the specific surface area of ​​the additive is controlled to be 20 m². 2 / g ~600 m 2 / g; The matrix is ​​electrochemically inert. By adding the additives of this embodiment to the battery, the strong electron-withdrawing ability of the CO bond in the crown ether group, compared with ordinary ethers, allows the large-ring cavity structure of the crown ether to more efficiently identify and complex metal impurities through size matching principles, effectively adsorbing metal impurities generated during battery cycling, and accelerating the desolvation of active metal ions, thereby improving the liquid phase transport efficiency of active metal ions in the negative electrode, and thus effectively improving the internal gas generation problem and the problem of increased internal resistance of the battery caused by metal impurities; by controlling the specific surface area of ​​the additive, the problem of side reactions with the electrolyte can be improved and the additive can have a strong liquid retention capacity, which greatly improves the amount of electrolyte retained in the electrode, providing a more complete liquid phase transport pathway for the transport of active metal ions. In addition, the matrix of this embodiment is electrochemically inert and will not consume active metal ions in the battery, which is beneficial to maintaining the battery life. Therefore, the system interaction of the crown ether group and the additive with the above-mentioned specific surface area can reduce the liquid phase diffusion resistance of the electrode, improve the liquid phase transport efficiency of active metal ions, and thus improve the battery life. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] Currently, rechargeable batteries suffer from low internal liquid phase mass transfer efficiency, which severely impacts battery life. Through long-term research, the inventors discovered that the cause of this problem lies in the drastic increase in electrode compaction density and areal density in pursuit of higher energy density rechargeable batteries. This prevents the electrolyte from fully penetrating the electrodes, hindering the mass transfer efficiency of active metal ions within the electrodes.

[0041] To address these issues, existing technologies have attempted to use electrolyte retention agents (such as polymers) to increase the amount of electrolyte retained in the electrode, thereby reducing the liquid phase diffusion resistance of the electrode to some extent. However, the improvement effect of this method is not satisfactory, and the above method does not provide an effective solution to the problem of metal impurity dissolution during battery cycling, making it difficult to improve battery life.

[0042] Therefore, the inventors aimed to improve the battery's lifespan by taking into account both the mass transfer efficiency and the problem of metal impurities.

[0043] Based on this, embodiments of the present invention provide an additive comprising a matrix and crown ether groups grafted onto the matrix; the additive has a specific surface area of ​​20 m². 2 / g ~600 m 2 / g, the matrix is ​​electrochemically inert.

[0044] The additives in this invention can enhance the liquid phase mass transfer capability of the electrode and effectively adsorb metal impurities generated during battery cycling, thereby effectively improving battery life.

[0045] The inventors analyzed that the additives in the embodiments of the present invention can improve the liquid phase mass transfer capability of the electrode and effectively adsorb metal impurities generated during battery cycling because: First, the additives in the embodiments of the present invention include a matrix that does not consume active metal ions (i.e., it has electrochemical inertness; the matrix material in the embodiments of the present invention does not undergo reversible redox reactions within the battery operating voltage window, does not participate in or participates less in charge storage, and does not or rarely interacts with active metal ions (such as Li⁺) in intercalation / deintercalation reactions), which is beneficial to maintaining the energy density of the battery. At the same time, the specific surface area of ​​the additive is controlled, which can simultaneously improve the problem of side reactions with the electrolyte and make the additive have a strong liquid retention capacity, which greatly improves the amount of electrolyte retained in the electrode, providing a more complete liquid phase transport pathway for the transport of active metal ions. Therefore, it can reduce the liquid phase diffusion resistance of the electrode, making the electrode have higher kinetics, which can reduce the internal resistance of the battery and improve the battery life. Furthermore, the additives in this embodiment of the invention include crown ether groups. Compared to ordinary ethers, the macrocyclic cavity structure of crown ethers can more efficiently identify and complex metal impurities through size matching principles. This effectively adsorbs metal impurities generated during battery cycling, inhibits the deposition of metal impurities on the negative electrode, effectively improves the battery gas generation problem caused by metal impurities, and extends battery life. The CO bond in the crown ether group has a strong electron-withdrawing ability, which can attract solvated active metal ions, accelerate the desolvation of active metal ions, improve the liquid phase transport efficiency of active metal ions in the negative electrode, reduce the battery's internal resistance, and extend battery life. Therefore, the additives in this embodiment of the invention can simultaneously improve the liquid phase mass transfer capability of the electrode and address the problem of increased metal impurity concentration during battery cycling, thereby effectively improving the battery's internal resistance and internal gas generation problem, and thus extending battery life.

[0046] In detail, the substrate of the present invention is electrochemically inert to active metal ions. Electrochemical inertness means that during battery cycling, the substrate does not consume active metal ions in the battery and does not participate in the insertion / extraction of active metal ions in the active materials of the positive and negative electrodes of the battery. Therefore, it can reduce the consumption of active metal ions in the battery and improve the cycle life of the battery.

[0047] The electrochemical inertness of the matrix in this invention is characterized by the volume change of the additive during battery cycling. If the additive consumes active metal ions, its volume will increase. Specifically, the electrochemical inertness of the matrix can be characterized using conventional testing methods and instruments. For example, XRD can be used to characterize the additive at different charge-discharge levels during battery cycling. If the structure of the additive does not change or the structural change does not exceed 1% during battery cycling (specifically characterized by the volume change rate), then the matrix can be proven to have electrochemical inertness.

[0048] For example, the specific surface area of ​​the additive can be 20 m². 2 / g、50 m 2 / g, 100 m 2 / g、200 m 2 / g、300m 2 / g、400 m 2 / g、500 m 2 / g、600 m 2 / g or a range consisting of any two of them.

[0049] In some embodiments of the present invention, the crown ether group in the additive can be detected by conventional testing methods and instruments in the art. For example, mass spectrometry (MS) can be used for detection. In a specific embodiment, the battery can be completely discharged and disassembled to obtain the positive electrode sheet (taking the positive electrode active material layer of the positive electrode sheet including the above-mentioned additive as an example). The positive electrode sheet is immersed in water to make the binder fail, and then the positive electrode active material layer is separated from the positive electrode current collector to obtain the positive electrode active material layer. The above positive electrode active material layer is heated at 300°C~400°C to remove the conductive agent and obtain a solid sample. Then, the above solid sample is placed in dilute acid to dissolve the positive electrode active material, and after washing and filtering, the additive is obtained. Mass spectrometry analysis can be used to detect the molecular ion peak of the sample (the above-mentioned additive) at [M+H]⁺=m / z 265, where [M+H]⁺ represents the protonated molecular ion formed after a neutral molecule captures a proton, and m / z 265 means that the mass-processed charge ratio is 265 (specifically, the characteristic molecular ion peak of the 18-crown-6 group in the mass spectrum).

[0050] In the additives of this invention, the specific surface area of ​​the additives can be detected using conventional testing methods and instruments in the art. For example, it can be tested using the BET method. Specifically, the battery can be completely discharged and disassembled to obtain the positive electrode sheet (taking the positive electrode active material layer containing the above-mentioned additive as an example). The positive electrode sheet is immersed in water to deactivate the binder. Then, the positive electrode active material layer is separated from the positive electrode current collector to obtain the positive electrode active material layer. The positive electrode active material layer is heated at 300℃~400℃ to remove the conductive agent and obtain a solid sample. The solid sample is then placed in dilute acid to dissolve the positive electrode active material. After washing and filtering, the additive is obtained. 0.1 g of the sample (the above-mentioned additive) can be placed in a Tristar II specific surface area and porosity analyzer with the following parameters set: degassing at 300℃ for 12 h, nitrogen adsorption at 77.35 K for 10 min, and then the specific surface area of ​​the additive can be obtained.

[0051] In detail, the matrix in the embodiments of the present invention refers to a material with a carbon content of less than 10%. For example, the matrix in the embodiments of the present invention can be a material whose core does not contain carbon elements but has a carbon coating layer. The crown ether group in the embodiments of the present invention can be directly grafted onto the matrix, or it can be grafted onto the matrix through other grafting groups.

[0052] In some embodiments of the present invention, when the Dv50 of the substrate is 1nm~800nm, the liquid retention capacity of the substrate and the problem of side reactions with the electrolyte can be further improved, which is conducive to better improving the liquid phase mass transfer capacity of the electrode and more effectively improving the internal resistance of the battery.

[0053] For example, the Dv50 of the substrate in the embodiments of the present invention can be a range of 1nm, 10nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm ​​or any combination thereof.

[0054] In the additives of this invention, the particle size can be detected using conventional testing methods and instruments in the art. For example, it can be tested using the PSA-LD laser diffraction particle size analysis method. Specifically, the battery can be completely discharged and disassembled to obtain the positive electrode sheet (taking the positive electrode active material layer containing the above-mentioned additive as an example). The positive electrode sheet is immersed in water to deactivate the binder. Then, the positive electrode active material layer is separated from the positive electrode current collector to obtain the positive electrode active material layer. The positive electrode active material layer is heated at 300℃~400℃ to remove the conductive agent and obtain a solid sample. The solid sample is then placed in dilute acid to dissolve the positive electrode active material. After washing and filtering, the additive is obtained. 3 g of the sample (the above-mentioned additive) can be placed in a Mastersizer 3000 laser diffraction particle size analyzer, and the additive can be dispersed in water. Spots are taken every 10 seconds, and the results are measured. This process is repeated three times, and the average value is taken to obtain the particle size of the additive.

[0055] In some embodiments of the present invention, the grafting rate of the crown ether group on the non-carbon material matrix is ​​0.0001% to 50%. More specifically, the grafting rate of the crown ether group on the matrix means that the crown ether group is directly or indirectly attached to the matrix. When the grafting rate of the crown ether group on the non-carbon material matrix is ​​within the above range, it can better improve the adsorption of metal impurities generated during battery cycling, and also better enhance the liquid-phase diffusion ability of active metal ions, thereby more effectively reducing the internal resistance of the battery.

[0056] For example, the grafting rate of the crown ether group on the matrix can be in the range of 0.0001%, 0.01%, 0.1%, 1%, 5%, 10%, 20%, 30%, 40%, 50%, or any combination thereof. Preferably, it is 5% to 30%.

[0057] In the additives of this invention, the grafting rate of crown ether groups on the matrix can be detected using conventional testing methods and instruments in the art. For example, it can be detected by thermogravimetric analysis (TGA). In one specific embodiment, the following method can be used for detection: Take 2 g of sample (additive), weigh its original weight as W1, keep it at 200℃~400℃ for 1-2 h, and record the weight of the product after the heat treatment as W2. The grafting rate = (W1-W2) / W1. To calculate the grafting rate more accurately, the thermogravimetric curve data of the ungrafted matrix can be tested and calibrated to jointly calculate the thermogravimetric ratio. In the embodiments of this invention, the matrix includes at least one of metal oxide matrix, non-metal oxide matrix, and metal phosphide matrix. This is beneficial for better improving the liquid phase mass transfer capability of the battery, thereby better reducing the internal resistance of the battery.

[0058] In some embodiments of the present invention, the matrix includes a metal oxide matrix, which includes one or more of aluminum oxide matrix, tin oxide matrix, cobalt oxide matrix, and titanium oxide matrix. This is more conducive to improving the liquid retention capacity of the additive, thereby better improving the liquid phase mass transfer capacity of the battery and further reducing the internal resistance of the battery.

[0059] In some embodiments, the matrix includes a non-metallic oxide matrix, which includes a silicon oxide matrix. This is more conducive to improving the liquid retention capacity of the additive, thereby better improving the liquid phase mass transfer capability of the battery and thus better reducing the internal resistance of the battery.

[0060] In some embodiments, the matrix includes a metal phosphide matrix, which includes one or more of aluminum phosphate matrix and iron phosphate matrix. This is more conducive to improving the liquid retention capacity of the additive, thereby better improving the liquid phase mass transfer capacity of the battery and thus better reducing the internal resistance of the battery.

[0061] When the matrix of the present invention has the above composition, it is more conducive to improving the liquid retention capacity of the additives, thereby better improving the liquid phase mass transfer capacity of the battery, and further reducing the internal resistance of the battery.

[0062] The present invention does not limit the composition of the crown ether group. For example, the crown ether group may be a substituted or unsubstituted oxygen atom crown ether group, or a substituted or unsubstituted heteroatom crown ether group.

[0063] In detail, in one specific embodiment, the crown ether group includes substituted or unsubstituted oxygen-atom crown ether groups, wherein the oxygen-atom crown ether group means a cyclic macrocyclic polyether group formed by an oxygen atom and a methylene group. When the crown ether group includes a substituent, any hydrogen atom of the methylene group in the aforementioned oxygen-atom crown ether group can be substituted, and the substituent can be, for example, an alkyl, phenyl, or carboxyl group.

[0064] In some embodiments, the crown ether group includes substituted or unsubstituted heteroatom crown ether groups, where the oxygen atom in the cyclic structure of the aforementioned oxygen atom crown ether group is replaced by other heteroatoms, such as nitrogen atoms, sulfur atoms, etc. When the crown ether group includes substituents, any hydrogen atom of the methylene group in the aforementioned heteroatom crown ether group can be substituted, and the substituents can be, for example, C1-C10 alkyl, phenyl, or carboxyl groups.

[0065] In some embodiments, when the crown ether group includes one or more of 12-crown-4, 15-crown-5, 18-crown-6, 21-crown-7, 2.2.1-cryptoether, 2.2.2-cryptoether, azacrown ether group, thiocrown ether group, selenocrown ether group, dibenzo-12-crown-4, dibenzo-15-crown-5, dibenzo-18-crown-6, dibenzo-21-crown-7, dibenzo-24-crown-8, and carboxylic acid-18-crown-6, the additive's ability to adsorb metal impurities is further enhanced. Simultaneously, it can better improve the liquid-phase diffusion ability of active metal ions, better reduce the battery's internal resistance, and better improve the battery's gas generation problem, thereby further improving the battery's lifespan.

[0066] In some embodiments of the present invention, the grafting group between the crown ether group and the matrix includes at least one of amide group, amino group, and urea group, which can better control the grafting rate of the crown ether group on the matrix, further improve the adsorption capacity of the additive for metal impurities and the liquid phase diffusion capacity of active metal ions, better reduce the internal resistance of the battery and better improve the problem of battery gas generation, and is more conducive to improving the battery life.

[0067] The embodiments of this invention can use conventional testing methods and instruments to characterize the grafted groups. For example, X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance (NMR) can be used to characterize the grafted groups. In specific implementation, the battery can be completely discharged and disassembled to obtain the positive electrode sheet (taking the positive electrode active material layer containing the above-mentioned additives as an example). The positive electrode sheet is immersed in water to deactivate the binder. Then, the positive electrode active material layer is separated from the positive electrode current collector to obtain the positive electrode active material layer. The positive electrode active material layer is heated at 300°C to 400°C to remove the conductive agent and obtain a solid sample. Then, the solid sample is placed in dilute acid to dissolve the positive electrode active material. After washing and filtering, the additives are obtained. One gram of sample can be taken into a Thermo Fisher Scientific-Escalab 250Xi / 250Xi+ instrument and scanned using an Al Kα (1486.6 eV) X-ray source. The full spectrum is then scanned, and the characteristic peak of the amide bond at N1s is detected (judgment method: use XPS to test whether the characteristic peak of the amide bond appears at 400.5 eV at N1s) to detect the grafting groups in the additive. Alternatively, 200 mg of the sample (the above additive) can be taken into a Magnetic Resonance (200–500 MHz) instrument, selecting 400–900 MHz (1H frequency), MAS probe, spectral width: -200ppm–200ppm, scan count: 2000–4000 times. The characteristic peak at a shift of 170ppm in the C spectrum of the additive (if the grafting group is an amide group) is then detected to detect the grafting groups in the additive.

[0068] This invention also provides a method for preparing the above-mentioned additive, comprising the following steps: subjecting a crown ether precursor, including a matrix precursor, to a polymerization reaction to obtain the additive; wherein the specific surface area of ​​the matrix precursor is 20 m². 2 / g ~600 m 2 / g.

[0069] The present invention, through the above-described method for preparing additives, can produce additives with good adsorption capacity for metal impurities and low liquid phase impedance. This is beneficial for reducing the internal resistance of the battery and improving the problem of gas generation, thereby improving battery life. The additives prepared by the above method have the following composition: the additives include a matrix and crown ether groups grafted onto the matrix; the specific surface area of ​​the additives is 20 m². 2 / g ~600 m 2 / g.

[0070] In this embodiment of the invention, the crown ether group can be directly attached to the matrix through a polymerization reaction, or it can be attached to the matrix through a polymerization reaction by other graft groups.

[0071] In some embodiments of the present invention, the matrix precursor is prepared by a method comprising the following steps: subjecting the matrix raw material to a first modification treatment using a first modifier to obtain a matrix precursor comprising a first grafting reactive group; wherein the first modifier comprises the first grafting reactive group. The matrix precursor obtained by the above method comprises the first grafting reactive group. Through the above treatment, the embodiments of the present invention enable crown ether groups to be better grafted onto the matrix.

[0072] In some embodiments of the present invention, when the first modifier includes an amino modifier, the first modification treatment has higher reactivity and is more conducive to the grafting reaction.

[0073] In this embodiment of the invention, the processing temperature, processing time, and molar ratio of the matrix raw material to the first modifier for the first modification treatment are not specifically limited and can be selected according to the actual situation.

[0074] In some embodiments of the present invention, the matrix raw material can be a non-carbon material raw material, which may include at least one of metal oxides, non-metal oxides, and metal phosphides, and can be determined based on the selection of the matrix in the additive. The selection of metal oxides, non-metal oxides, and metal phosphides is as described above and will not be repeated here. For example, if the matrix is ​​a metal oxide matrix, then the matrix raw material is a metal oxide; the same applies to non-metal oxides and metal phosphides.

[0075] In some embodiments of the present invention, the matrix raw material is further dried before the first modification treatment to remove moisture. The embodiments of the present invention do not impose special limitations on the drying temperature and time, which can be selected according to actual conditions. For example, the drying time can be 8 hours to 16 hours, and the drying temperature can be 200°C to 400°C.

[0076] In some embodiments of the present invention, when the amino modifier includes one or more of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-(methacryloyloxy)propyltri(2-methoxyethoxy)silane, the polymerization reaction has higher reactivity and is more conducive to the synthesis of additives.

[0077] In some embodiments of the present invention, the first modification treatment can be carried out in a solvent. For example, the solvent for the first modification treatment can be toluene.

[0078] In some embodiments of the present invention, the crown ether precursor is prepared by a method comprising the following steps: subjecting the crown ether raw material to a second modification treatment using a second modifier to obtain the crown ether precursor; wherein the second modifier includes a second grafting reactive group. The crown ether precursor obtained by the above preparation method includes the second grafting reactive group. Through the above treatment, the crown ether groups can be better grafted onto the matrix in the embodiments of the present invention.

[0079] In some embodiments of the present invention, when the second modifier includes at least one of a carboxylic acid modifier, an acyl chloride modifier, an epoxy modifier, and an isocyanate modifier, the second modification treatment has higher reactivity and is more conducive to the polymerization reaction.

[0080] In this embodiment of the invention, the processing temperature, processing time, and molar ratio of crown ether precursor to second modifier for the second modification treatment are not specifically limited and can be selected according to actual conditions.

[0081] In some embodiments of the present invention, in order to make the second modification treatment more efficient, a catalyst may be added to the second modification treatment, for example, the catalyst may be K2CO3.

[0082] In some embodiments of the present invention, the second modification treatment can be carried out in a solvent. The solvent for the second modification treatment can be N,N-dimethylformamide (DMF).

[0083] In some embodiments of the present invention, the crown ether precursor includes substituted or unsubstituted oxygen crown ether compounds and substituted or unsubstituted heteroatom crown ether compounds, which can be selected according to the specific type of crown ether group in the additive, and will not be elaborated here.

[0084] In one specific embodiment, when the first grafting reaction group is amino (i.e., the first modifier is an amino modifier) ​​and the second grafting reaction group is carboxyl or acyl chloride (i.e., the second modifier is a carboxylic acid modifier or acyl chloride modifier), the grafting group generated after the grafting reaction is an amide group; when the first grafting reaction group is amino (i.e., the first modifier is an amino modifier) ​​and the second grafting reaction group is epoxy (i.e., the second modifier is an epoxy modifier), the grafting group generated after the grafting reaction is a urea group; when the first grafting reaction group is amino (i.e., the first modifier is an amino modifier) ​​and the second grafting reaction group is isocyanate (i.e., the second modifier is an isocyanate modifier), the grafting group generated after the grafting reaction is a urea group.

[0085] In this embodiment of the invention, the crown ether group (provided by a crown ether precursor) is grafted onto the matrix via a second grafting reactive group and a first grafting reactive group. Specifically, the first grafting reactive group and the second grafting group undergo a grafting reaction to generate a grafting group, thereby grafting the crown ether group onto the matrix.

[0086] Preferably, the polymerization reaction temperature is 20℃~30℃, which increases the reactivity of the grafting reaction and is more conducive to its progress. For example, the polymerization reaction temperature can be 20℃, 25℃, 30℃, or any combination thereof.

[0087] In some embodiments, the polymerization reaction time is 12h to 60h, which results in higher polymerization reactivity and is more conducive to the grafting reaction.

[0088] Preferably, the reaction time of the polymerization reaction can be a range of 12h, 20h, 30h, 40h, 50h, 60h, or any combination thereof.

[0089] In some embodiments of the present invention, the polymerization reaction can be carried out in a solvent. The present invention does not impose any special limitations on the choice of solvent and can select one according to actual circumstances. For example, the solvent for the grafting reaction can be DMF.

[0090] To further improve the efficiency of the grafting reaction, in some embodiments of the present invention, a condensing agent may be added to the grafting reaction. The embodiments of the present invention do not impose special limitations on the type and amount of the condensing agent, and can select it according to actual conditions. For example, the condensing agent can be at least one of benzotriazol-1-yl-tetramethylureonium hexafluorophosphate (HATU) or N,N-diisopropylethylamine (DIEA). The molar ratio of the condensing agent to the crown ether precursor can be (0.01~0.5):1.

[0091] It is understandable that, in order to better improve the purity of the additives, the first modification treatment, the second modification treatment, and the grafting reaction can be carried out in an inert atmosphere (such as nitrogen).

[0092] In this embodiment of the invention, the grafting rate of crown ether groups on the matrix can be controlled by controlling the molar ratio of the matrix precursor and the crown ether precursor.

[0093] This invention also provides a battery element comprising the above-described additive, or an additive prepared by the above-described additive preparation method. The battery element of this invention has advantages corresponding to the above-described additive, which will not be elaborated upon here.

[0094] In some embodiments of the present invention, the battery element includes at least one of a positive electrode, a negative electrode, and a separator, which can more effectively reduce the internal resistance of the battery and better improve the problem of gas generation in the battery. Preferably, the battery element includes a positive electrode.

[0095] In some embodiments, the battery element includes a positive electrode, which includes the additives described above.

[0096] In some embodiments, the battery element includes a negative electrode sheet, the negative electrode sheet including the above-mentioned additives. Preferably, the matrix of the additives does not include carbon-containing and silicon-containing compounds; preferably, the matrix of the additives includes a metal oxide matrix and a metal phosphide; preferably, the matrix of the additives includes one or more of an aluminum oxide matrix, a tin oxide matrix, a cobalt oxide matrix, a titanium oxide matrix, an aluminum phosphate matrix, and an iron phosphate matrix.

[0097] In some embodiments, the battery element includes a separator, which includes the additives described above.

[0098] In some embodiments, the battery element includes an electrolyte, which includes the additives described above, and the matrix of the additives is preferably an alumina matrix.

[0099] Specifically, when the battery element includes a positive electrode, the aforementioned additive may be included in at least one positive electrode active material layer; when the battery element includes a negative electrode, the aforementioned additive may be included in at least one negative electrode active material layer; when the battery element includes a separator, the aforementioned additive may be included in at least one separator coating on the separator substrate. When the battery element includes an electrolyte, the aforementioned additive may be added to the electrolyte.

[0100] In some embodiments of the present invention, the battery element includes a component substrate and a functional coating disposed on at least one side of the component substrate. The functional coating includes the additives mentioned above. When the mass percentage of the additives in the functional coating is 0.001wt% to 70wt%, the internal resistance of the battery can be reduced more effectively and the problem of battery gas generation can be improved better.

[0101] For example, the mass percentage of the additive in the functional coating can be 0.001 wt%, 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, or any combination thereof. Preferably, it is 1 wt% to 8 wt%.

[0102] In detail, when the battery element of the present invention includes a positive electrode sheet, the above-mentioned functional coating can be a functional coating in which additives are uniformly dispersed in the positive electrode active material layer, that is, the functional coating is the positive electrode active material layer, and the element substrate is the positive electrode current collector; the same applies to the negative electrode sheet.

[0103] Specifically, the battery element includes a positive electrode sheet, which includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, wherein the positive active material layer includes the aforementioned additives.

[0104] In some embodiments, a first positive electrode functional layer is disposed between the positive electrode active material layer and the positive electrode current collector, and the first positive electrode functional layer includes the aforementioned additives.

[0105] In some embodiments, a second positive electrode functional layer is provided on the side of the positive electrode active material layer facing away from the positive electrode current collector, and the second positive electrode functional layer includes the above-mentioned additives.

[0106] When the battery element in this embodiment of the invention is a separator, the above-mentioned functional coating can be a functional coating in which additives are uniformly dispersed in the separator coating, and the element substrate is a separator substrate (e.g., polyethylene, polypropylene, etc.).

[0107] In this embodiment of the invention, the mass percentage of the additive in the functional coating can be detected using conventional testing methods and instruments in the art. For example, it can be tested using the ICP method. Specifically, the Thermo Fisher Scientific ICAP PRO X can be used, and the specific operation is as follows: Take 5g of the additive sample and put it into a sample bottle, add an appropriate amount of aqua regia and heat to dissolve for 20s, filter to obtain the first solution, and after the first solution cools, put it into the sample chamber to test and analyze the element content, obtain the concentration of the corresponding element in the obtained first solution, and thus obtain the content percentage of the corresponding element in the additive material.

[0108] This invention also provides a battery including the above-described battery elements. The battery of this invention has advantages corresponding to the above-described additives, which will not be elaborated here.

[0109] The battery in this embodiment of the invention can be a lithium-ion battery (such as a lithium-ion power battery), a potassium-ion battery, a sodium-ion battery, or other novel energy storage batteries, preferably a lithium-ion battery.

[0110] Specifically, the positive electrode sheet includes a positive current collector and a positive active material layer located on at least one side surface of the positive current collector. Specifically, the positive active material layer can be provided on one side surface in the thickness direction of the positive current collector, or positive active material layers can be provided on both opposite sides surface in the thickness direction of the positive current collector.

[0111] The positive electrode active material layer also includes positive electrode active material, positive electrode conductive agent, and positive electrode binder. In the positive electrode active material layer, the mass percentage of positive electrode active material can be 70% to 99%, for example, 70%, 75%, 80%, 85%, 90%, 93%, 95%, 97%, 99%, or any combination thereof. The mass fraction of positive electrode conductive agent can be 0.5% to 15%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15%, or any combination thereof. The mass fraction of positive electrode binder can be 0.5% to 15%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15%, or any combination thereof.

[0112] In some embodiments, the battery is a sodium-ion battery, and the positive electrode active material includes, but is not limited to, one or a combination of transition metal oxides, polyanionic compounds, organic compounds, and Prussian blue materials. The transition metal oxides may be, but are not limited to, NaMO2 (M may be Fe, Co, Ni, Mn, etc.); the polyanionic compounds may be, but are not limited to, Na3V2(PO4)3, NaFePO4, Na2FePO4F, etc.; the Prussian blue materials may be, but are not limited to, Na2Fe(CN)6, etc.; and the organic compounds may be, but are not limited to, sodium terephthalic acid salts, etc.

[0113] In some embodiments, the battery is a lithium-ion battery, and the positive electrode active material may include LiCoO2, LiNiO2, or LiCo. x Ni 1-x O2 (0≤x≤1), LiCo x Ni 1-x-y Al y O2 (0≤x≤1, 0≤y≤1), LiMn2O4, LiFe x Mn y M z O4 (M is one or more of Al, Mg, Ga, Cr, Co, Ni, Cu, Zn or Mo, 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1), Li 1＋ x L 1－y－z M y N zO2 (L, M, N are one or more of Li, Co, Mn, Ni, Fe, Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo, F, I, S, B, -0.1≤x≤0.2, 0≤y≤1, 0≤z≤1, 0≤y+z≤1), LiFePO4, Li3V2(PO4)3, Li3V3(PO4)3, LiVPO4F, Li2CuO2, Li5FeO4, and metal sulfides and oxides (such as TiS2, V2S3, FeS, FeS2, LiMS) x (M is at least one of the transition metal elements such as Ti, Fe, Ni, Cu, Mo, etc., 1≤x≤2.5), TiO2, Cr3O8, V2O5, MnO2, etc.

[0114] In some embodiments, the battery is a potassium-ion battery, and the positive electrode active material includes, but is not limited to, one or more of the following: Prussian blue analogues, layered transition metal oxides, polyanionic compounds (such as KFeSO4F, KVPO4F), organic compounds (such as potassium terephthalate), sulfides (such as K2FeS2), phosphates (such as K3V2(PO4)3), potassium manganese oxides (such as KMnO4 derivatives), potassium cobalt oxides (such as KCoO2), and potassium nickel oxides (such as KNiO2).

[0115] In this embodiment of the invention, the positive electrode conductive agent in the positive electrode active material layer can be a conventional conductive material in the art. For example, the positive electrode conductive agent in the positive electrode active material layer may include one or more of conductive carbon black, conductive graphite, carbon nanotubes (CNTs), carbon fibers, graphene, acetylene black, and Ketjen black.

[0116] In this embodiment of the invention, the positive electrode binder in the positive electrode active material layer can be a conventional binder in the art. For example, the positive electrode binder in the positive electrode active material layer may include one or more of the following: polyvinylidene fluoride (PVDF), polyvinylidene fluoride, polyvinyl fluoride, polyethylene, polypropylene, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, etc.

[0117] The embodiments of the present invention may employ conventional positive current collectors in the art, for example, positive current collectors may include aluminum foil.

[0118] In this embodiment of the invention, the positive electrode sheet can be prepared by conventional methods in the art, such as by coating. Specifically, the components used to form the positive electrode active material layer, such as the positive electrode conductive agent and the positive electrode binder, can be dispersed in a solvent, such as N-methylpyrrolidone (NMP), to prepare a positive electrode slurry. This slurry is then coated onto the surface of the positive electrode current collector, and after drying, rolling, and other processes, the positive electrode sheet is obtained. The coating, drying, and rolling processes involved are conventional operations for preparing positive electrode sheets using the coating method, and are not particularly limited thereto.

[0119] In practice, a slurry containing positive electrode active material can be prepared at a temperature of 20℃~45℃; conventional coating equipment in the field, such as continuous coating equipment, can be used to coat the slurry containing positive electrode active material onto the surface of the positive electrode current collector.

[0120] The electrolyte in this embodiment of the invention can be a conventional electrolyte in the art. For example, the electrolyte is a non-aqueous electrolyte, which may specifically include organic solvents, additives and electrolyte salts. Organic solvents include one or more of ethylene carbonate (EC), diethyl carbonate (DEC) and propylene carbonate (PC). Additives include, for example, fluoroethylene carbonate (FEC) and vinylene carbonate (VC). Electrolyte salts may include lithium salts (if it is a lithium-ion battery), such as lithium hexafluorophosphate (LiPF6), but are not limited thereto.

[0121] In a preferred embodiment, the battery is a sodium-ion battery, and the electrolyte comprises, by mass percentage, 5% to 20% NaPF6, 30% to 60% propylene carbonate (PP), 30% to 50% ethyl methyl carbonate (EMC), 2% to 5% fluoroethylene carbonate (FEC), 0.1% to 0.8% propylene-1,3-sulfonyl lactone (PST), and 0.2% to 0.8% vinyl sulfate (DTD).

[0122] In this embodiment of the invention, the separator is used to separate the positive and negative electrode plates, preventing short circuits caused by contact between them. Conventional separators in the art can be used in this embodiment, and there are no particular limitations. For example, the separator material can be one or more of the following: high-density polyethylene, ultra-high-density polyethylene, low-density polyethylene, linear low-density polyethylene, high-density polypropylene, ultra-high-density polypropylene, polyimide, and polyvinylidene fluoride.

[0123] In this embodiment of the invention, the battery cell can be packaged using conventional housing materials in the art, such as flexible packaging materials like aluminum-plastic film, but is not limited thereto.

[0124] The embodiments of the present invention can assemble components such as positive electrode, separator and negative electrode into a battery using conventional methods in the art. For example, positive electrode, separator and negative electrode can be stacked in an alternating manner to obtain a stacked cell (or wound into a wound cell); then the cell is placed in a casing (outer packaging) and after conventional processes such as electrolyte injection (i.e., injection of electrolyte) and encapsulation, the battery is obtained.

[0125] This invention also provides a battery pack comprising at least two of the above-described batteries, which has advantages corresponding to the above-described additives, and will not be described in detail hereafter.

[0126] Generally, a battery pack includes multiple batteries as individual cells, which are connected to form the battery pack. These batteries can be electrically connected using methods conventional in the art, such as series connection, parallel connection, or a combination of these connection methods, without any particular limitation.

[0127] This invention also provides an electrical device, including the battery or battery pack described above. This electrical device has advantages corresponding to the additives described above, which will not be elaborated further.

[0128] The electrical equipment used in the embodiments of the present invention can be conventional electrical equipment in the art, such as power equipment (e.g., electric vehicles, electric cars), electronic equipment (e.g., mobile phones, tablets, laptops, digital cameras, etc.), wearable devices (e.g., watches, bracelets, VR glasses, etc.), energy storage power stations, etc., and there are no particular limitations on this.

[0129] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0130] Example 1

[0131] The negative electrode sheet in this embodiment is prepared by the following method:

[0132] 1) The matrix raw material (specifically alumina) is vacuum dried at 300℃ for 12 hours to remove physically adsorbed water. The molar ratio of matrix to first modifier (specifically 3-aminopropyltriethoxysilane) is controlled to be 5:1. The matrix is ​​refluxed in toluene for the first modification treatment at 110℃ for 24 hours to obtain the matrix precursor.

[0133] 2) The crown ether raw material (specifically 12-crown ether-4) and the second modifier (specifically bromoacetic acid) were subjected to a second modification treatment in a K2CO3 / DMF system (treatment temperature was 60℃, treatment time was 8h) to obtain the crown ether precursor.

[0134] 3) Dissolve 1g of matrix precursor and 0.5mmol of crown ether precursor in an anhydrous solvent (specifically N,N-dimethylformamide), then add a condensing agent (specifically 0.55mmol benzotriazol-1-yl-tetramethylureonium hexafluorophosphate and 1.1mmol N,N-diisopropylethylamine), and carry out the polymerization reaction under nitrogen protection at a reaction temperature of 25℃ for 48h to obtain the additive.

[0135] 4) The above-mentioned additives, graphite, binder (specifically sodium carboxymethyl cellulose), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain a negative electrode slurry. This slurry is then coated onto the surface of the copper foil of the negative electrode current collector of the component substrate. After drying, rolling and other processes, a negative electrode sheet is obtained. The negative electrode slurry forms a functional coating, and the additives account for 1 wt% of the mass of the functional coating.

[0136] Example 2

[0137] This embodiment is basically the same as embodiment 1, except that in step 4) of this embodiment, the additives, graphite, binder (specifically CMC) and conductive agent (specifically carbon black) are mixed in a mass ratio of 2:94.5:2:1.5 to obtain the negative electrode slurry.

[0138] Example 3

[0139] This embodiment is basically the same as that of embodiment 1, except that the amount of matrix precursor and crown ether precursor used in step 3) of this embodiment is different from that in embodiment 1, resulting in a different grafting rate of crown ether groups on the matrix.

[0140] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 8:88.5:2:1.5 to obtain the negative electrode slurry.

[0141] Example 4

[0142] This embodiment is basically the same as that of embodiment 1, except that in step 3) of this embodiment, the crown ether raw material is 12-crown-4:aza-18-crown-6 mixed in a molar ratio of 8:2.

[0143] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain the negative electrode slurry.

[0144] Example 5

[0145] This embodiment is basically the same as that of embodiment 1, except that in step 3) of this embodiment, the crown ether raw material is 12-crown-4:aza-18-crown-6 mixed in a molar ratio of 5:5.

[0146] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain the negative electrode slurry.

[0147] Example 6

[0148] This embodiment is basically the same as that of embodiment 1, except that in step 3) of this embodiment, the crown ether raw material is 12-crown-4:aza-18-crown-6 mixed in a molar ratio of 2:8.

[0149] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain the negative electrode slurry.

[0150] Example 7

[0151] This embodiment is basically the same as that of embodiment 1, except that in step 3) of this embodiment, the crown ether raw material is a mixture of azir-18-crown-6 and 18-crown-6-dicarboxylic acid in a molar ratio of 5:5.

[0152] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain the negative electrode slurry.

[0153] Example 8

[0154] This embodiment is basically the same as that of embodiment 1, except that in step 3) of this embodiment, the crown ether raw material is a mixture of 12-crown-4:aza-18-crown-6:18-crown-6-dicarboxylic acid in a molar ratio of 1:1:1.

[0155] In step 4) of this embodiment, the additives, graphite, binder (specifically CMC), and conductive agent (specifically carbon black) are mixed in a mass ratio of 1:95.5:2:1.5 to obtain the negative electrode slurry.

[0156] Example 9

[0157] The difference between this embodiment and Example 1 is that the matrix in this embodiment is aluminum phosphate, and the specific surface area and average particle size of the additives are different from those in Example 1. See Table 1 for details.

[0158] Example 10

[0159] The difference between this embodiment and Example 1 is that the matrix of this embodiment is silicon oxide, and the specific surface area and average particle size of the additives are different from those of Example 1, as detailed in Table 1.

[0160] Example 11

[0161] This embodiment is basically the same as that of embodiment 1, except that the amount of matrix precursor and crown ether precursor used in step 3) of this embodiment is different from that in embodiment 1, resulting in a different grafting rate of crown ether groups on the matrix.

[0162] Example 12

[0163] This embodiment is basically the same as that of embodiment 1, except that the amount of matrix precursor and crown ether precursor used in step 3) of this embodiment is different from that in embodiment 1, resulting in a different grafting rate of crown ether groups on the matrix.

[0164] Example 13

[0165] This embodiment is basically the same as that of embodiment 1, except that the amount of matrix precursor and crown ether precursor used in step 3) of this embodiment is different from that in embodiment 1, resulting in a different grafting rate of crown ether groups on the matrix.

[0166] Example 14

[0167] This embodiment is basically the same as embodiment 1, except that in step 4) of this embodiment, the additives, graphite, binder (specifically CMC) and conductive agent (specifically carbon black) are mixed in a mass ratio of 70:26.5:2:1.5 to obtain the negative electrode slurry.

[0168] Example 15

[0169] This embodiment is basically the same as embodiment 1, except that in step 4) of this embodiment, the additive, graphite, binder (specifically CMC) and conductive agent (specifically carbon black) are mixed in a mass ratio of 0.001:96.499:2:1.5 to obtain the negative electrode slurry.

[0170] Example 16

[0171] This embodiment is basically the same as embodiment 1, except that in step 4) of this embodiment, the additives, graphite, binder (specifically CMC) and conductive agent (specifically carbon black) are mixed in a mass ratio of 75:21.5:2:1.5 to obtain the negative electrode slurry.

[0172] Example 17

[0173] This embodiment is basically the same as embodiment 1, except that in step 4) of this embodiment, the additives, graphite, binder (specifically CMC) and conductive agent (specifically carbon black) are mixed in a mass ratio of 0.0005:96.4995:2:1.5 to obtain the negative electrode slurry.

[0174] Example 18

[0175] This embodiment is basically the same as embodiment 1, except that step 4) in this embodiment is to mix the additive, positive electrode active material LFP, binder PVDF and conductive agent CNT in a mass ratio of 1:96.5:2:1.5 to obtain a positive electrode slurry, and then coat it on the surface of the positive electrode current collector aluminum foil. After drying, rolling and other processes, a positive electrode sheet is obtained.

[0176] Example 19

[0177] This embodiment is basically the same as embodiment 1, except that step 4) in this embodiment is to mix the additive and the binder (specifically CMC) at a mass ratio of 1:4 to obtain a diaphragm coating slurry, and then coat it on both sides of the Celgard2400 polypropylene membrane diaphragm substrate, and obtain the diaphragm after drying.

[0178] Comparative Example 1

[0179] The difference between this comparative example and Example 1 is that no additives are added in this comparative example. The negative electrode slurry of this comparative example is a mixture of graphite, binder (specifically CMC), and conductive agent (specifically carbon black) in a mass ratio of 100:2:1.5.

[0180] Comparative Example 2

[0181] The difference between this comparative example and Example 1 is that the specific surface area and average particle size of the additive in this comparative example are different from those in Example 1, as detailed in Table 1.

[0182] Comparative Example 3

[0183] The difference between this comparative example and Example 1 is that the specific surface area and average particle size of the additive in this comparative example are different from those in Example 1, as detailed in Table 1.

[0184] Comparative Example 4

[0185] The difference between this comparative example and Example 1 is that the matrix of this comparative example does not have grafted crown ether groups.

[0186] The types of substrates (hereinafter referred to as substrates), categories of crown ether functional groups (hereinafter referred to as crown ether functional groups), specific surface areas of additives (hereinafter referred to as specific surface areas), Dv50 of additives (hereinafter referred to as Dv50), grafting rate of crown ether groups on the substrate (hereinafter referred to as grafting rate), and mass percentage of additives in the functional coatings (hereinafter referred to as additive percentage) in the above embodiments and comparative examples are shown in Table 1.

[0187] Assemble the battery:

[0188] The negative electrode sheet and lithium iron phosphate positive electrode sheet from Examples 1-17 and Comparative Examples 1-4 above, with Celgard 2400 polypropylene membrane as separator, diethyl carbonate and ethylene carbonate as electrolyte in a volume ratio of 7:3, and LiPF6 as electrolyte salt at a concentration of 1 mol / L, were assembled, impregnated, formed, aged, and capacity tested to produce a small soft-pack battery.

[0189] Using the positive electrode sheet and graphite negative electrode from Example 18 above, and a Celgard 2400 polypropylene membrane as the separator, and diethyl carbonate and ethylene carbonate as the electrolyte with a volume ratio of 7:3, and LiPF6 as the electrolyte salt with a concentration of 1 mol / L, a small soft-pack battery was prepared by assembly, impregnation, formation, aging, and capacity testing.

[0190] Using the separator from Example 19 above, along with lithium iron phosphate positive electrode, graphite negative electrode, and Celgard 2400 polypropylene membrane as separators, and diethyl carbonate and ethylene carbonate as electrolytes in a volume ratio of 7:3, with LiPF6 as the electrolyte salt at a concentration of 1 mol / L, a small soft-pack battery was prepared through assembly, impregnation, formation, aging, and capacity testing.

[0191] Test case

[0192] (a) Physical property testing

[0193] The battery can be completely discharged and then disassembled to obtain the positive electrode sheet (taking the positive electrode active material layer of the positive electrode sheet as an example, which includes the above-mentioned additives). The positive electrode sheet is immersed in water to make the binder fail. Then, the positive electrode active material layer is separated from the positive electrode current collector to obtain the positive electrode active material layer. The positive electrode active material layer is heated at 350°C to remove the conductive agent and obtain a solid sample. Then, the solid sample is placed in dilute acid to dissolve the positive electrode active material. After washing and filtering, the additives are obtained.

[0194] (1) Types of functional groups

[0195] Mass spectrometry analysis can be used to detect the molecular ion peak of the sample (the above-mentioned additive) at [M+H]⁺=m / z 265, where [M+H]⁺ represents the protonated molecular ion formed after a neutral molecule captures a proton, and m / z 265 means that the mass-processed charge ratio is 265 (specifically, the characteristic molecular ion peak of the 18-crown-6 group in the mass spectrum).

[0196] X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance (NMR) can be used in combination to characterize grafted groups. Specifically, 1g of sample can be placed in a Thermo Fisher Scientific-Escalab 250Xi / 250Xi+ instrument using an Al Kα (1486.6 eV) X-ray source for full-spectrum scanning. The characteristic peak of the amide bond at N 1s can then be detected (judgment method: whether the characteristic peak of the amide bond appears at 400.5 eV in the N 1s region using XPS) to detect grafted groups in the additive. Alternatively, 200mg of sample (the above-mentioned additive) can be placed in a Magnetic Resonance (200–500 MHz) instrument, selecting 400–900 MHz (1H frequency), MAS probe, spectral width: -200ppm–200ppm, scan number: 2000–4000 times. The characteristic peak of the C spectrum of the additive at a shift of 170ppm can then be detected to detect grafted groups in the additive. The grafting groups in the additives were found to be amide groups by XPS and solid-state NMR methods in Examples 1-19 and Comparative Examples 2-4 of the present invention.

[0197] (2) Specific surface area of ​​additives

[0198] The BET method can be used for testing. Take 0.1 g of the sample (the above additive) into a Tristar II surface area and porosity analyzer, set the parameters as follows: degas at 300℃ for 12 h, nitrogen adsorption at 77.35 K for 10 min, and then perform the test to obtain the specific surface area of ​​the additive.

[0199] (3) Dv50 of additives

[0200] The particle size can be tested using the PSA-LD laser diffraction particle size analysis method. Specifically, take 3 g of the sample (the above-mentioned additive) in a Mastersizer 3000 laser diffraction particle size analyzer, disperse it in water, take a sample every 10 seconds, and then perform the test. Repeat this process three times and take the average value to obtain the particle size of the additive.

[0201] (4) Grafting rate of crown ether groups on the matrix

[0202] Thermogravimetric analysis (TGA) can be used for detection. Specifically, take 2 g of sample (additive), record its original weight as W1, incubate at 300℃ for 1 hour, and record the weight of the product after incubation as W2. Grafting rate = (W1-W2) / W1. To calculate the grafting rate more accurately, the thermogravimetric curve data of the ungrafted matrix can be tested and calibrated, and the thermogravimetric ratio can be calculated together.

[0203] (5) Mass percentage of additives in functional coatings

[0204] The ICP method can be used for testing. The Thermo Fisher Scientific ICAP PRO X can be used, and the specific procedure is as follows: Take 5g of the additive sample and place it in a sample vial, add an appropriate amount of aqua regia, heat to dissolve for 20 seconds, filter to obtain the first solution, and after the first solution cools, place it in the sample chamber. Test and analyze the elemental content to obtain the concentration of the corresponding element in the obtained first solution, thus obtaining the content percentage of the corresponding element in the additive material.

[0205] (6) Electrochemical inertness test of the matrix

[0206] The additives of the present invention were tested using XRD. The volume of the additives of the present invention did not exceed 1% during battery cycling. The matrix of the present invention is electrochemically inert.

[0207]

[0208] (ii) Battery performance testing

[0209] (1) Battery internal resistance test

[0210] The aforementioned small pouch battery was connected to the Blue Electric Electrochemical Test Channel instrument for battery internal resistance testing. Specifically, the battery internal resistance of the aforementioned small pouch battery was tested at 25℃-3C-10s (test temperature was 25℃, charging rate was 3C, and the fast charge / discharge time was 10s). The results are shown in Table 2.

[0211] (2) Battery gas generation test

[0212] Using the water displacement method, the initial volume of the small pouch battery in the above embodiments and comparative examples is recorded as V1. Then, the volume of the small pouch battery in the above embodiments and comparative examples after being stored at 60°C for 30 days is recorded as V2. V2-V1 is recorded as the gas production volume of the battery. The results are shown in Table 2 (gas production during storage at 60°C).

[0213] (3) Test for metal impurity content in batteries

[0214] The small pouch batteries of the above embodiments and comparative examples were stored at 60°C for 30 days. The batteries were then disassembled, the negative electrode sheet was separated, and the negative electrode active material layer was scraped off. ICP testing was then used to determine the content of metal impurities in the negative electrode sheet. The results are shown in Table 2 (Negative Electron Fe). +3 ).

[0215]

[0216] As shown in the table, compared to the comparative example, the embodiments of the present invention, by using additives grafted with crown ether groups onto the matrix, can effectively adsorb metallic impurities generated in the battery, and are beneficial to improving the battery's internal resistance and reducing battery gas production. Compared to Example 13, Example 1 of the present invention further improves the battery's internal resistance and reduces battery gas production by controlling the grafting rate of crown ether groups; compared to Examples 16 and 17, Example 1 of the present invention further improves the battery's internal resistance and reduces battery gas production by controlling the mass ratio of the additive in the functional coating.

[0217] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An additive, characterized in that, Includes the matrix and crown ether groups grafted onto the matrix; The specific surface area of ​​the additive is 20 m². 2 / g ~600 m 2 / g; The matrix is ​​electrochemically inert.

2. The additive according to claim 1, characterized in that, The additive has a Dv50 of 100nm to 800nm; And / or, the grafting rate of the crown ether group on the matrix is ​​0.0001% to 50%; preferably 5% to 30%.

3. The additive according to claim 1 or 2, characterized in that, The matrix includes at least one of a metal oxide matrix, a non-metal oxide matrix, and a metal phosphide matrix.

4. The additive according to claim 1, characterized in that, The matrix includes a metal oxide matrix, which includes one or more of aluminum oxide matrix, tin oxide matrix, cobalt oxide matrix, and titanium oxide matrix; And / or, the matrix comprises a non-metallic oxide matrix, wherein the non-metallic oxide matrix comprises a silicon oxide matrix; And / or, the matrix comprises a metal phosphide matrix, wherein the metal phosphide matrix comprises one or more of aluminum phosphate matrix and iron phosphate matrix; And / or, the crown ether groups include 12-crown-4, 15-crown-5, 18-crown-6, and 21-crown-7 groups. 2.2.1-Cavitrile group, 2.2.2-Cavitrile group, azirocrown ether group, thiocrown ether group, selenocrown ether group, dibenzo-12-crown-4-yl, dibenzo-15-crown-5-yl, dibenzo-18-crown-6-yl, dibenzo-21-crown-7-yl, dibenzo-24-crown-8-yl, carboxylic acid-18-crown-6-yl.

5. The additive according to any one of claims 1-4, characterized in that, It includes a grafting group that connects the crown ether group to the matrix, and the grafting group includes at least one of amide, amino, and urea groups.

6. A method for preparing the additive according to any one of claims 1-5, characterized in that, Includes the following steps: The additive is obtained by polymerizing the matrix precursor and the crown ether precursor. The specific surface area of ​​the matrix precursor is 20 m². 2 / g ~600 m 2 / g.

7. The method for preparing the additive according to claim 6, characterized in that, The method for preparing the matrix precursor includes the following steps: The matrix raw material is subjected to a first modification treatment using a first modifier to obtain the matrix precursor; Wherein, the first modifier includes a first grafting reactive group; preferably, the first modifier includes one or more of 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-(methacryloyloxy)propyltri(2-methoxyethoxy)silane.

8. The method for preparing the additive according to claim 6 or 7, characterized in that, The preparation method of the crown ether precursor includes the following steps: The crown ether raw material is subjected to a second modification treatment using a second modifier to obtain the crown ether precursor; The second modifier includes a second grafted reactive group; preferably, the second modifier includes one or more of carboxylic acid modifiers, acyl chloride modifiers, epoxy modifiers, and isocyanate modifiers.

9. The method for preparing the additive according to claim 7 or 8, characterized in that, The polymerization reaction includes: condensing the second graft reactive group in the crown ether precursor with the first graft reactive group in the matrix precursor to obtain the additive; Preferably, the polymerization reaction temperature is 20℃~30℃; Preferably, the polymerization reaction takes place over a period of 12 to 60 hours.

10. A battery element, characterized in that, This includes the additives described in any one of claims 1-5, or the additives prepared by the method described in any one of claims 6-9.

11. The battery element according to claim 10, characterized in that, The battery element includes a positive electrode, and the positive electrode includes the additive; And / or, the battery element includes a negative electrode, the negative electrode including the additive; And / or, the battery element includes a separator, the separator including the additive; And / or, the battery element includes an electrolyte, the electrolyte including the additive, the matrix of the additive preferably being an alumina matrix.

12. The battery element according to claim 11, characterized in that, The battery element includes an element substrate and a functional coating disposed on at least one side of the element substrate. The functional coating includes the additive, and the additive accounts for 0.001 wt% to 70 wt% by mass in the functional coating; preferably 1 wt% to 8 wt%.

13. A battery, characterized in that, Includes the battery element as described in any one of claims 10-12.

14. A battery pack, characterized in that, It includes at least two batteries as described in claim 13.

15. An electrical appliance, characterized in that, Includes the battery of claim 13 or the battery pack of claim 14.

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