Positive Electrode Material Composition, Positive Electrode, Secondary Battery, and Electric Device

Abstract

The present application provides a positive electrode material composition, a positive electrode, a secondary battery, and an electrical device. The positive electrode material composition contains a positive electrode active material and dielectric material particles, where the A value of the dielectric material particles is 50 to 200, A = [ε / (c / a)], ε is the relative permittivity of the dielectric material particles, c is the length of the c-axis of the unit cell of the dielectric material particles, and a is the length of the a-axis of the unit cell of the dielectric material particles.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a cathode material composition, a cathode, a secondary battery, and an electrical device.

Background Art

[0002] In recent years, as the application range of secondary batteries has been expanding, secondary batteries are widely used in energy storage power systems such as hydraulic, thermal, wind, and solar power plants, as well as in multiple fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. Since secondary batteries have achieved great development, higher requirements have also been put forward for their energy density, cycle performance, etc.

[0003] The wide application of lithium-ion battery-powered electric vehicles is accelerating. However, compared with conventional fuel vehicles, problems such as range anxiety and long charging time have become the main problems hindering the development of electric vehicles. Therefore, the improvement of fast charging ability has become a common development goal for battery manufacturers and complete vehicle manufacturers.

Summary of the Invention

[0004] In view of the above problems, the present application provides a novel cathode material composition, a cathode, a secondary battery, and an electrical device. The following will be described respectively.

[0005] According to a first aspect, the present application provides a cathode material composition containing a cathode active material and dielectric material particles, wherein the A value of the dielectric material particles is 50 to 200, A = [ε / (c / a)], where ε is the relative permittivity of the dielectric material particles, c is the length of the c-axis of the unit cell of the dielectric material particles, and a is the length of the a-axis of the unit cell of the dielectric material particles.

[0006] The cathode material composition based on the above-described embodiment is used in a secondary battery that exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency in the first cycle, reduced charge resistance, and long cycle life.

[0007] In the above-described embodiment, it is crucial for improving the performance of the secondary battery that the A value of the dielectric material particles is 50 to 200. This is because during the high-current charge and discharge process of a secondary battery (e.g., a lithium-ion battery), cations in the cathode film move to the interface between the cathode active material and the electrolyte. There is a solid electrolyte interface film (CEI film) on the surface of the cathode active material, and since the insertion / desorption barrier of the solvated cations in the CEI film is high, some cations accumulate at the interface, causing concentration polarization. At the same time, due to the impedance of the CEI film, the migration speed of cations in the CEI film becomes slow, leading to a high discharge DCR and a reduction in the overall power output of the cell. When the dielectric material particles are excited by an electric field, the centers of positive and negative charges in the material are separated, generating an internal reverse electric field. The reverse electric field forms a triple-phase interface at the boundary of the electrolyte, dielectric material particles, and cathode active material. Since the triple-phase interface is thin, lithium ions can be inserted and desorbed quickly. The A value of the dielectric material particles is 50 to 200, which can significantly increase the insertion / desorption speed of solvated lithium ions in the CEI film.

[0008] In some embodiments, the relative permittivity of the dielectric material particles is 80 to 200. Based on this embodiment, the permittivity of the dielectric material particles and the permittivity of the electrolyte generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency in the first cycle, reduced charge resistance, and long cycle life.

[0009] In some embodiments, the length of the c-axis of the unit cell of the dielectric material particles is 0.3 nm to 0.5 nm. Based on this embodiment, the permittivity of the dielectric material particles and the permittivity of the electrolyte generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency in the first cycle, reduced charge resistance, and long cycle life.

[0010] In some embodiments, the length of the a-axis of the unit cell of the dielectric particles is 0.3 nm to 0.5 nm. Based on this form, the dielectric constant of the dielectric particles and the dielectric constant of the electrolyte generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0011] In some embodiments, the dielectric particles are one or more selected from barium titanate particles, lead titanate particles, lithium niobate particles, lead zirconate titanate particles, lead metaniobate particles, and lithium barium lead niobate particles.

[0012] In some embodiments, the positive electrode active material is one or more selected from the following. (1) Layered oxide type positive electrode active material, (2) Spinel type positive electrode active material, (3) Polyanion type positive electrode active material.

[0013] In some embodiments, the dielectric particles are cubic barium titanate particles. Based on this form, the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0014] In some embodiments, the volume median diameter of the dielectric particles is 50 to 100 nm. Based on this form, the dielectric particles can be well bonded to the surface of the positive electrode active material, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0015] In some embodiments, the volume median diameter of the positive electrode active material is 4 to 10 μm. Based on this form, the dielectric material particles can be well bonded to the surface of the positive electrode active material, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0016] In some embodiments, the ratio of the volume median diameter of the dielectric material particles to that of the positive electrode active material is 1:40 to 1:200. Based on this form, the dielectric material particles can be well bonded to the surface of the positive electrode active material, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0017] In some embodiments, the dielectric material particles adhere to the surface of the positive electrode active material.

[0018] In some embodiments, the mass ratio of the dielectric material particles to the positive electrode active material is 1:100 to 10:100.

[0019] According to a second aspect, the present application provides a positive electrode containing the positive electrode material composition according to any one of the above items.

[0020] According to a third aspect, the present application provides a secondary battery containing a positive electrode film layer and an electrolytic solution, wherein the positive electrode film layer contains the positive electrode material composition containing the positive electrode active material and the dielectric material particles according to any one of the above items, and provides a secondary battery in which the ratio of the relative dielectric constant of the dielectric material particles to that of the electrolytic solution is 50 to 200:30 to 90. Based on this, an impedance matching effect can be further generated between the surface of the relative dielectric constant material and the electrolytic solution, contributing to the rapid desorption and insertion of solvated lithium ions.

[0021] According to a fourth aspect, the present application provides an electric device including the secondary battery according to any one of the above items. [Beneficial effects]

[0022] The positive electrode material composition, positive electrode, secondary battery, and electric device according to the present application have one or more of the following effects. (1) When the positive electrode material composition is used in a secondary battery, the secondary battery exhibits an improved specific capacity. (2) When the positive electrode material composition is used in a secondary battery, the secondary battery exhibits an improved Coulomb efficiency in the first cycle. (3) When the positive electrode material composition is used in a secondary battery, the secondary battery exhibits a reduced charge resistance. (4) When the positive electrode material composition is used in a secondary battery, the secondary battery exhibits a long cycle life.

Brief Description of the Drawings

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Modes for Carrying Out the Invention

[0024] Hereinafter, with appropriate reference to the drawings, embodiments of the negative electrode active material, its manufacturing method, positive electrode plate, negative electrode plate, secondary battery, battery module, battery pack, and device of the present application will be described in detail and specifically disclosed. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of actually similar structures may be omitted. This is to avoid making the following description unnecessarily long and to enable those skilled in the art to easily understand. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the gist described in the claims.

[0025] The "range" disclosed in the present application is limited in the form of a lower limit and an upper limit. A predetermined range is limited by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundary of a special range. The range limited in this way may or may not include extreme values and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, when ranges of 60 to 120 and 80 to 110 are given for a specific parameter, it is also expected to be understood as ranges of 60 to 110 and 80 to 120. Note that when minimum range values 1 and 2 are given, and maximum range values 3, 4, and 5 are given, the following ranges: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all predictable. In the present application, unless otherwise specified, the numerical range "a~b" indicates an abbreviated representation of any combination of real numbers from a to b, and in particular, both a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers from "0~5" are listed in this specification, but "0~5" is only an abbreviated representation of the combination of these numerical values. Also, when it is indicated that a certain parameter is an integer of 2 or more, it corresponds to the disclosure that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] Unless otherwise specified, all embodiments and selectable embodiments of the present application can be combined with each other to form new technical means.

[0027] Unless otherwise specified, all technical features and selectable technical features of this application can be combined with each other to form new technical means.

[0028] Unless otherwise specified, all steps of this application may be performed in order or randomly, but it is preferred to perform them in order. For example, when it is said that the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed in order, or steps (b) and (a) performed in order. For example, when it is said that the above-mentioned method may further include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), steps (a), (c) and (b), steps (c), (a) and (b), etc.

[0029] Unless otherwise specified, the "including" and "comprising" mentioned in this application indicate an open type and may also be a closed type. For example, the "including" and "comprising" can indicate that other components not listed may be further included or comprised, or only the listed components may be included or comprised.

[0030] Unless otherwise specified, the term "or" in this application is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions also satisfies the condition "A or B". A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist). [Secondary battery]

[0031] A secondary battery is also called a rechargeable battery or a storage battery, and means a battery that can continue to be used by activating the active material by a charging method after discharging the battery.

[0032] In general, a secondary battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. During the charge and discharge process of the battery, active ions (such as lithium ions) repeatedly intercalate and deintercalate between the positive electrode plate and the negative electrode plate. The separator is provided between the positive electrode plate and the negative electrode plate, mainly serving to prevent short circuit between the positive and negative electrodes and allowing active ions to pass through. The electrolyte mainly serves to conduct active ions between the positive electrode plate and the negative electrode plate. [Positive electrode material composition]

[0033] According to a first aspect, the present application provides a positive electrode material composition containing a positive electrode active material and dielectric material particles, wherein the A value of the dielectric material particles is 50 to 200, A = [ε / (c / a)], ε is the relative permittivity of the dielectric material particles, c is the length of the c-axis of the unit cell of the dielectric material particles, and a is the length of the a-axis of the unit cell of the dielectric material particles.

[0034] The positive electrode of a secondary battery containing the above positive electrode material composition shows one or more improvements, such as an improvement in specific capacity, an improvement in the Coulomb efficiency of the first cycle, a reduction in charge resistance, and an increase in cycle life.

[0035] In the above embodiment, it is crucial for improving battery performance that the A value is between 50 and 200. This is because during the high-current charge and discharge process of a battery (e.g., a lithium-ion battery), cations in the positive electrode film move to the interface between the positive electrode active material and the electrolyte. There is a solid electrolyte interface film (CEI film) on the surface of the positive electrode active material, and since the insertion / desorption barrier of solvated cations in the CEI film is high, some cations accumulate at the interface, resulting in concentration polarization. At the same time, due to the impedance of the CEI film, the migration rate of cations in the CEI film becomes slow, leading to a high discharge DCR and a reduction in the overall power output of the cell. When dielectric particles are excited by an electric field, the centers of positive and negative charges in the material are separated, generating an internal reverse electric field. The reverse electric field forms a triple-phase interface at the boundary of the three phases of the electrolyte, dielectric particles, and positive electrode active material. Since the triple-phase interface is thin, lithium ions can be inserted and desorbed rapidly. When the A value of the dielectric constant is between 50 and 200, solvated lithium ions can be inserted and desorbed into the CEI film rapidly, and furthermore, one or more performances of the battery, such as improvement in capacity, improvement in Coulomb efficiency in the first cycle, reduction in charge resistance, and improvement in cycle life, can be improved.

[0036] In some embodiments, the term "unit cell" means a parallelepiped unit that can fully reflect the characteristics of the chemical structure in which atoms inside a crystal are distributed in three-dimensional space. The unit cell can also maintain the symmetry of the crystal structure and is furthermore the smallest unit mentioned in the crystal. The shape and size of the unit cell are related to the lengths of its three axes a, b, and c (i.e., the three side lengths of the parallelepiped unit). The c-axis can correspond to the longest axis in the unit cell, and the a-axis can correspond to the shortest axis in the unit cell.

[0037] The wavelength of X-rays (0.01 nm to 10 nm) and the parameters of the unit cell are of the same order, and usually, the parameters of the unit cell of a crystal are measured by the X-ray diffraction method.

[0038] In some embodiments, the dielectric particles belong to a crystalline system, and the unit cell parameters satisfy a = b, a ≠ c, b ≠ c, and the a-axis, b-axis, and c-axis are perpendicular to each other.

[0039] In some embodiments, the A value of the positive electrode material composition is 50 - 60, 60 - 70, 70 - 80, 80 - 90, 90 - 100, 100 - 110, 110 - 120, 120 - 130, 130 - 140, 140 - 150, 150 - 160, 160 - 170, 170 - 180, 180 - 190, or 190 - 200.

[0040] In some embodiments, the relative permittivity of the dielectric particles is 80 - 200. Based on this form, an impedance matching effect can be generated between the surface of the relative permittivity material and the electrolyte solution, and the rapid charging performance of the secondary battery is improved.

[0041] In some embodiments, the term "relative permittivity" means relative permittivity (ε r ), which is the ratio of the relative permittivity of the material to the relative permittivity of vacuum (ε 0 ).

[0042] In some embodiments, the permittivity means the permittivity at room temperature (25 ± 5 °C), has the meaning well-known in this field, and can be tested by instruments and methods well-known in this field. For example, after manufacturing a ferroelectric material into a circular sample, the capacitance C is measured by an LCR tester, and can be calculated by the formula: permittivity ε = (C × d) / (ε 0 × A). C represents the capacitance, and the unit is farad (F). d represents the thickness of the sample, and the unit is cm. A represents the area of the sample, and the unit is cm 2 . ε 0 represents the vacuum permittivity, and ε 0 = 8.854×10 -14 F / cm. In this application, the test conditions may be 1 KHz, 1.0 V, 25 ± 5 °C. The test standard may conform to GB / T 11297.11 - 2015. When manufacturing the sample, Chinese Patent Application CN114217139A may be referred to.

[0043] In some embodiments, the relative permittivity of the present application can be measured by a relative permittivity measuring instrument. Specifically, GB / T5594.4-1985 may be referred to. The instrument can select the ZJD-C relative permittivity measuring instrument of Beijing Zhonghang Times Instrument Equipment Co., Ltd.

[0044] In some embodiments, the relative permittivity of the dielectric material particles is 50-60, 60-70, 70-80, 80-90, 90-100, 100-110, 110-120, 120-130, 130-140, 140-150, 150-160, 160-170, 170-180, 180-190 or 190-200. Based on this form, the permittivity of the dielectric material particles and the permittivity of the electrolyte generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0045] In some embodiments, the length of the c-axis of the unit cell of the dielectric material particles is 0.3 nm to 0.5 nm (for example, 0.3 nm to 0.34 nm, 0.34 nm to 0.38 nm, 0.38 nm to 0.40 nm, 0.40 nm to 0.42 nm, 0.42 nm to 0.46 nm, 0.46 nm to 0.5 nm). Based on this form, the permittivity of the dielectric material particles and the permittivity of the electrolyte generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0046] In some embodiments, the length of the a-axis of the unit cell of the dielectric particles is 0.3 nm to 0.5 nm (for example, 0.3 nm to 0.34 nm, 0.34 nm to 0.38 nm, 0.38 nm to 0.40 nm, 0.40 nm to 0.42 nm, 0.42 nm to 0.46 nm, 0.46 nm to 0.5 nm). Based on this form, the dielectric constant of the dielectric particles and the dielectric constant of the electrolyte solution generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0047] In some embodiments, the ratio (c / a) of the length of the c-axis to the length of the a-axis of the unit cell of the dielectric particles is 0.3 to 0.5:0.3 to 0.5, for example, 0.38 to 0.42:0.38 to 0.42, for example, 0.401 to 0.405:0.395 to 0.399. Based on this form, the dielectric constant of the dielectric particles and the dielectric constant of the electrolyte solution generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0048] In some embodiments, the dielectric particles are one or more selected from barium titanate particles, lead titanate particles, lithium niobate particles, lead zirconate titanate particles, lead metaniobate particles, and lead barium lithium niobate particles. Based on this form, the dielectric constant of the dielectric particles and the dielectric constant of the electrolyte solution generate an impedance matching effect, and the secondary battery exhibits one or more improved performances such as improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0049] In some embodiments, the chemical formula of lead zirconate titanate is Pb x Zr 1-x TiO 3 where 0 < x < 1.

[0050] In some embodiments, the chemical formula of lead barium lithium niobate is (Pb x Ba1-x ) 4 Li 2 Nb 10 O 30 where 0 < x < 1.

[0051] In some embodiments, the positive electrode active material is one or more selected from the following. (1) Layered oxide type positive electrode active material (e.g., ternary material), (2) Spinel type positive electrode active material (e.g., lithium manganese oxide material), (3) Polyanion type positive electrode active material (e.g., lithium iron phosphate material).

[0052] In some embodiments, the dielectric material particles are cubic barium titanate particles.

[0053] In some embodiments, the term "cubic" refers to a crystal structure having a unit cell containing three axes, two of which have the same length and are perpendicular to each other, and the third axis is perpendicular to the other two axes.

[0054] In some embodiments, the volume median diameter of the dielectric material particles is 50 - 100 nm, for example 50 - 60 nm, 60 - 70 nm, 70 - 80 nm, 80 - 90 nm or 90 - 100 nm. Based on this, the dielectric material particles and the positive electrode active material have a good bond, and the dielectric material particles are difficult to detach from the positive electrode active material.

[0055] In some embodiments, the volume median diameter of the positive electrode active material is 4 - 10 μm, for example 4 - 5 μm, 5 - 6 μm, 6 - 7 μm, 7 - 8 μm, 8 - 9 μm or 9 - 10 μm. Based on this, the dielectric material particles and the positive electrode active material have a good bond, and the dielectric material particles are difficult to detach from the positive electrode active material.

[0056] In some embodiments, the ratio of the volume median diameter of the dielectric material particles to the positive electrode active material is 1:40 - 1:200, for example 1:50 - 1:100, for example 1:50 - 70. Based on this, the dielectric material particles and the positive electrode active material have a good bond, and the dielectric material particles are difficult to detach from the positive electrode active material.

[0057] In some embodiments, the dielectric particles adhere to the surface of the positive electrode active material.

[0058] In some embodiments, the term "adhere" has a general meaning such as contact, connection, bonding, or adhesion. The process involved when adhering dielectric particles to the positive electrode active material may include chemical ionic bonds and covalent bonds, surface tension, van der Waals forces, capillary forces, electrostatic interactions, adhesion, and any other physical processes that connect two entities. For example, the dielectric particles can be adhered to the surface of the positive electrode active material by an adhesive. For example, the dielectric particles can be crimped to the surface of the positive electrode active material by pressure.

[0059] In some embodiments, the mass ratio of the dielectric particles to the positive electrode active material is 1:100 to 10:100, for example 3:100 to 7:100.

[0060] According to a second aspect, the present application provides a positive electrode containing the positive electrode material composition according to any one of the above items.

[0061] According to a third aspect, the present application provides a secondary battery containing a positive electrode film layer and an electrolytic solution, wherein the positive electrode film layer contains the positive electrode material composition containing the positive electrode active material and the dielectric particles according to any one of the above items, and provides a secondary battery in which the ratio of the relative dielectric constant of the dielectric particles to the electrolytic solution is 50 to 200:30 to 90. Based on this, an impedance matching effect can be generated between the surface of the relative dielectric constant material and the electrolytic solution, contributing to the rapid desorption and insertion of solvated lithium ions.

[0062] According to a fourth aspect, the present application provides an electric device including the secondary battery according to any one of the above items. [Positive electrode plate]

[0063] In some embodiments, the positive electrode plate generally includes a positive electrode current collector and a positive electrode film layer containing a positive electrode active material provided on at least one surface of the positive electrode current collector.

[0064] As an example, the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is provided on either one or both of the two opposing surfaces of the positive electrode current collector.

[0065] In some embodiments, a metal foil or a composite current collector may be used for the positive electrode current collector. For example, as the metal foil, an aluminum foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base (such as a base of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0066] In some embodiments, the positive electrode active material may be a positive electrode active material used in batteries, which is well-known in the art. As an example, the positive electrode active material may include at least one of materials such as lithium-containing phosphates having an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery may be further used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides are lithium cobalt oxide (e.g., LiCoO 2 ), lithium nickel oxide (e.g., LiNiO 2 ), lithium manganese oxide (e.g., LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3Co 1 / 5 n 1 / 3 O 2 (NCM 333 (may be abbreviated as LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM 523 (may be abbreviated as LiNi 0.5 Co 0.25 Mn 0.25 O 2 (NCM 211 (may be abbreviated as LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622 (may be abbreviated as LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811 Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and modified compounds thereof, but are not limited thereto. Examples of lithium-containing phosphates having an olivine structure include lithium iron phosphate (e.g., LiFePO 4 (which may be abbreviated as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (e.g., LiMnPO 4 ), a composite of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite of lithium iron manganese phosphate and carbon, but is not limited thereto.

[0067] In some embodiments, the positive electrode membrane layer may further include an optional adhesive. For example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0068] In some embodiments, the positive electrode film layer may further optionally contain a conductive agent. By way of example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0069] In some embodiments, the positive electrode plate can be manufactured by the following method. Components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, an adhesive, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry. The positive electrode slurry is applied to a positive electrode current collector and, after undergoing processes such as drying and cold pressing, a positive electrode plate is obtained. [Electrolyte]

[0070] The electrolyte serves to conduct ions between the positive electrode plate and the negative electrode plate. This application has no specific restrictions on the type of electrolyte, and it may be selected as needed. For example, the electrolyte may be in a liquid state, a gel state, or an all-solid state.

[0071] In some embodiments, the electrolyte is liquid and contains an electrolyte salt and a solvent.

[0072] In some embodiments, the electrolyte salt may be at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, lithium bisoxalate difluorophosphate, and lithium tetrafluoro(oxalate)phosphate.

[0073] In some embodiments, the solvent may be at least one selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluorinated ethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0074] In some embodiments, the electrolyte may optionally further contain an additive. As an example, the additive may include a negative electrode film-forming additive and a positive electrode film-forming additive, and may further include an additive that can improve certain performance of the battery, such as an additive that improves the overcharge performance of the battery, an additive that improves the high-temperature or low-temperature performance of the battery, etc. [Separator]

[0075] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of the separator, and any well-known separator having a porous structure with good chemical stability and mechanical stability can be selectively used.

[0076] In some embodiments, the material of the separator may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer thin film or a multi-layer composite thin film, and there is no particular limitation. When the separator is a multi-layer composite thin film, the materials of each layer may be the same or different, and there is no particular limitation.

[0077] In some embodiments, the positive electrode plate, the negative electrode plate, and the separator can be used to manufacture an electrode assembly by a winding process or a lamination process.

[0078] In some embodiments, the secondary battery may include an external package. The external package is used to seal the above electrode assembly and electrolyte.

[0079] In some embodiments, the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, etc. The outer packaging of the secondary battery may also be a soft packaging material, such as a pouch-type soft packaging material. The material of the pouch may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0080] The present application has no particular limitation on the shape of the secondary battery, and it may be cylindrical, rectangular, or any other arbitrary shape. For example, FIG. 3 shows a rectangular-structured secondary battery 5 as an example.

[0081] In some embodiments, referring to FIG. 4, the outer packaging may include a case 51 and a cover plate 53. Among them, the case 51 may include a base plate and side plates connected to the base plate, and the base plate and the side plates surround to form an accommodation cavity. The case 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can be covered and installed in the opening so as to close the accommodation cavity. The positive electrode plate, the negative electrode plate, and the separator can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is sealed in the accommodation cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, and those skilled in the art can select according to specific actual requirements.

[0082] In some embodiments, the secondary battery may be assembled as a battery module, and the number of secondary batteries included in the battery module may be one or more. Specifically, those skilled in the art can select according to the application and capacity of the battery module.

[0083] FIG. 5 shows a battery module 4 as an example. Referring to FIG. 5, in the battery module 4, a plurality of secondary batteries 5 may be arranged in sequence in the longitudinal direction of the battery module 4. Of course, they may be arranged according to any other method. Furthermore, the plurality of secondary batteries 5 can be fixed by fastening members.

[0084] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of secondary batteries 5 are accommodated in the accommodation space.

[0085] In some embodiments, the battery module may be further assembled as a battery pack. The number of battery modules included in the battery pack may be one or more. Specifically, those skilled in the art can select according to the application and capacity of the battery pack.

[0086] FIGS. 6 and 7 show a battery pack 1 as an example. Referring to FIGS. 6 and 7, the battery pack 1 may include a battery housing and a plurality of battery modules 4 provided in the battery housing. The battery housing includes an upper housing 2 and a lower housing 3. The upper housing 2 is covered and installed on the lower housing 3, and it is possible to form a closed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery housing according to any method.

[0087] In addition, the present application further provides an electrical device including at least one of the secondary battery, battery module, or battery pack provided by the present application. The secondary battery, battery module, or battery pack may be used as a power source of the electrical device, or may be used as an energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as battery electric vehicles, hybrid vehicles, plug-in hybrid vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), trains, ships, satellites, energy storage systems, etc.

[0088] As the electric device, a secondary battery, a battery module, or a battery pack can be selected according to the requirements of its use.

[0089] FIG. 8 shows an electric device as an example. The electric device is a battery-powered electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, or the like. In order to meet the requirements for high power and high energy density of the secondary battery of the electric device, a battery pack or a battery module may be used.

[0090] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only for explaining the present application and should not be construed as limiting the present application. When specific technologies or conditions are not clarified in the embodiments, they are carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. When the reagents or instruments used are not specified by the manufacturer, they are all general products that can be obtained by purchasing from the market. [Production Example 1]

[0091] Barium titanate particles with different relative permittivities were produced.

[0092] Commercially available raw material barium titanate particles (cubic crystal system, abbreviated as BTO raw material) with a particle size of 100 nm and a relative permittivity of 30 were provided.

[0093] The raw material barium titanate particles were ball-milled to obtain barium titanate particles with different relative permittivities. Planetary ball mill was used for ball milling, agate balls were used as grinding balls, the ball material ratio was 2:1, and barium titanate particles with different relative permittivities (σ) were obtained by adjusting the ball milling time (t). The correspondence between the ball milling parameters and the relative permittivity of the barium titanate particles is as shown in the following table.

[0094]

Table 1

[0095] The method for measuring the relative permittivity of barium titanate particles is as follows. In this application, the relative permittivities of barium titanate particles and the electrolyte can be measured by a relative permittivity measuring instrument. Specifically, GB / T5594.4 - 1985 may be referred to. The instrument can select the ZJD - C relative permittivity measuring instrument of Beijing Zhonghang Times Instrument Equipment Co., Ltd.

[0096] The method for measuring the a value and c value of barium titanate particles is as follows. Barium titanate particles are subjected to powder X-ray diffraction analysis, the obtained XRD spectrum is trimmed, and it can be calculated based on the Rietveld method.

[0097] After mixing the dielectric material particles and the positive electrode active material, the positive electrode material composition according to this application was obtained. The positive electrode material composition can be further fabricated as a positive electrode and used in a secondary battery. [Production Example 2]

[0098] By adjusting the composition of the electrolyte, an electrolyte with a relative permittivity of 90 was produced. The correspondence between the composition of the electrolyte and the relative permittivity is as shown in the following table.

[0099]

Table 2

[0100] The method for measuring the relative permittivity of the electrolyte is as follows.

[0101] In this application, the relative permittivity of the dielectric particles and the electrolyte can be measured by a relative permittivity measuring instrument. Specifically, reference may be made to GB / T5594.4-1985. The instrument can select the ZJD-C relative permittivity measuring instrument of Beijing Zhonghang Times Instrument Equipment Co., Ltd. [Example 1]

[0102] Manufacture of full cell: Lithium nickel cobalt manganate (NCM523, i.e., LiNi 0.5 Co 0.2 Mn 0.3 O 2 , Dv50 = 5μm), an adhesive (PVDF), a conductive agent (acetylene black SP), and barium titanate particles (BTO-90) with a relative permittivity of 90 were mixed at a weight ratio of 97:1:1:1. N-methylpyrrolidone (NMP) was added as a solvent, and the slurry was stirred until uniform in a vacuum state. The obtained slurry was applied to a 13-μm aluminum foil by a blade at a surface density of 13.7 mg / cm 2 , and then dried at 140°C and cold pressed. A positive electrode film containing a positive electrode active material and dielectric particles (barium titanate particles) was formed on the aluminum foil. After cutting, a positive electrode plate was obtained.

[0103] Manufacture of negative electrode plate: Artificial graphite as the negative electrode active material, acetylene black as the conductive agent, styrene-butadiene rubber (SBR) as the adhesive, and sodium carboxymethyl cellulose (CMC) as the dispersant were dissolved in deionized water as the solvent at a weight ratio of 97:1:1:1, stirred and mixed uniformly, and then made into a negative electrode slurry. The negative electrode slurry was uniformly applied to a 7-μm copper foil of the negative electrode current collector at a coating density of 9.7 mg / cm 2 , and a negative electrode plate was obtained through drying, cold pressing, and cutting.

[0104] Electrolyte: The electrolyte with a relative permittivity of 90 manufactured above was used.

[0105] Separator: A microporous membrane of a PP-PE copolymer with a commercially available thickness of 20 μm and an average pore diameter of 80 nm (model number 20 from AET) was used.

[0106] The positive electrode plate, separator, and negative electrode plate were stacked in order, with the separator positioned between the positive and negative electrodes to play a role in isolation, and a wound bare cell was obtained. The bare cell was placed in an external package, the above electrolyte was injected and sealed, and a secondary battery was obtained.

[0107] Figure 1 shows a schematic diagram of the battery. The battery includes an electrode membrane 100 and an electrolyte 200 impregnated in the electrode membrane 100. The electrode membrane 100 includes a positive electrode membrane layer 101 and a negative electrode membrane layer 102. The battery further includes a separator 300 that separates the positive electrode membrane layer 101 and the negative electrode membrane layer 102. The positive electrode membrane layer 101 contains a positive electrode active material and dielectric material particles.

[0108] Figure 2 shows a schematic diagram of the electrode membrane. The positive electrode membrane layer 101 contains a positive electrode active material 201 and dielectric material particles 202. Optionally, the dielectric material particles 202 adhere to the surface of the positive electrode active material 201. [Examples 1a - 1b, Comparative Example 1]

[0109] The difference between Example 1a and Example 1 is that barium titanate particles with a relative permittivity of 90 (BTO - 90) are replaced with barium titanate particles with a relative permittivity of 60 (BTO - 60).

[0110] The difference between Example 1b and Example 1 is that barium titanate particles with a relative permittivity of 90 (BTO - 90) are replaced with barium titanate particles with a relative permittivity of 120 (BTO - 120).

[0111] The difference between Comparative Example 1 and Example 1 is that barium titanate particles with a relative permittivity of 90 (BTO - 90) are replaced with conductive carbon black. [Example 2]

[0112] Manufacture of full cell: Lithium nickel cobalt manganate (NCM811, i.e., LiNi 0.8 Co 0.1 Mn0.1 O 2 , Dv50 is 5 μm), an adhesive (PVDF), a conductive agent (acetylene black SP), and barium titanate particles (BTO-120) with a relative permittivity of 120 were mixed at a weight ratio of 97:1:1:1, and N-methylpyrrolidone (NMP) was added as a solvent, and the slurry was stirred until uniform in a vacuum state. The resulting slurry had a surface density of 13.7 mg / cm 2 and was coated on a 13-μm aluminum foil by a blade, and then dried at 140 °C and cold-pressed. A positive electrode film containing a positive electrode active material and dielectric material particles (barium titanate particles) was formed on the aluminum foil. After cutting, a positive electrode plate was obtained.

[0113] Fabrication of negative electrode plate: Artificial graphite was used as the negative electrode active material, acetylene black was used as the conductive agent, styrene-butadiene rubber (SBR) was used as the adhesive, and sodium carboxymethyl cellulose (CMC) was used as the dispersant. They were dissolved in ion-exchanged water as the solvent at a weight ratio of 97:1:1:1, stirred and mixed uniformly, and then fabricated into a negative electrode slurry. The negative electrode slurry was uniformly coated on a 7-μm copper foil of the negative electrode current collector at a coating density of 9.7 mg / cm 2 , and a negative electrode plate was obtained through drying, cold pressing, and cutting.

[0114] Electrolyte: The electrolyte with a relative permittivity of 70 manufactured above was used.

[0115] Separator: A commercially available PP-PE copolymer microporous membrane (type number 20 from AET) with a thickness of 20 μm and an average pore diameter of 80 nm was used.

[0116] The positive electrode plate, separator, and negative electrode plate were stacked in order, and the separator was located between the positive and negative electrodes to play a role in isolation, and a wound bare cell was obtained. The bare cell was placed in an external package, the above electrolyte was injected and sealed, and a secondary battery was obtained. [Examples 2a to 2b, Comparative Example 2]

[0117] The difference between Example 2a and Example 2 is that barium titanate particles with a relative permittivity of 120 (BTO-120) are replaced with barium titanate particles with a relative permittivity of 90 (BTO-90).

[0118] The difference between Example 2b and Example 2 is that barium titanate particles with a relative permittivity of 120 (BTO-120) are replaced with barium titanate particles with a relative permittivity of 150 (BTO-150).

[0119] The difference between Comparative Example 2c and Example 2 is that barium titanate particles with a relative permittivity of 120 (BTO-120) are replaced with conductive carbon black. [Example 3]

[0120] Manufacture of full cell: Lithium iron phosphate (LiFePO 4 , Dv50 = 5 μm), an adhesive (PVDF), a conductive agent (acetylene black SP), and barium titanate particles with a relative permittivity of 150 (BTO-150) were mixed at a weight ratio of 97:1:1:1, N-methylpyrrolidone (NMP) was added as a solvent, and the slurry was stirred until uniform under a vacuum. The obtained slurry was applied to a 13-μm aluminum foil by a blade at a surface density of 13.7 mg / cm 2 , and then dried at 140 °C and cold-pressed. A positive electrode film containing a positive electrode active material and dielectric material particles (barium titanate particles) was formed on the aluminum foil. After cutting, a positive electrode plate was obtained.

[0121] Manufacture of negative electrode plate: Artificial graphite as the negative electrode active material, a conductive agent (acetylene black), styrene-butadiene rubber (SBR) as the adhesive, and sodium carboxymethyl cellulose (CMC) as the dispersant were dissolved in ion-exchanged water as the solvent at a weight ratio of 97:1:1:1, stirred and mixed uniformly, and then manufactured into a negative electrode slurry. The negative electrode slurry was uniformly applied to a 7-μm copper foil of the negative electrode current collector at a coating density of 9.7 mg / cm 2 , and a negative electrode plate was obtained through drying, cold pressing, and cutting.

[0122] Electrolyte: An electrolyte with a relative permittivity of 30 produced as described above was used.

[0123] Separator: A PP-PE copolymer microporous membrane (model number 20 from AET) with a thickness of 20 μm and an average pore diameter of 80 nm, which is commercially available, was used.

[0124] The positive electrode plate, separator, and negative electrode plate were stacked in order. The separator was located between the positive and negative electrodes to play a role in isolation, and a wound bare cell was obtained. The bare cell was placed in an external package, and the above electrolyte was injected and sealed to obtain a secondary battery. [Examples 3a - 3b, Comparative Example 3]

[0125] The difference between Example 3a and Example 3 is that barium titanate particles (BTO - 150) with a relative permittivity of 150 are replaced with barium titanate particles (BTO - 120) with a relative permittivity of 120.

[0126] The difference between Example 3b and Example 3 is that barium titanate particles (BTO - 150) with a relative permittivity of 150 are replaced with barium titanate particles (BTO - 180) with a relative permittivity of 180.

[0127] The difference between Comparative Example 3 and Example 3 is that barium titanate particles (BTO - 150) with a relative permittivity of 150 are replaced with conductive carbon black. [Comparative Examples 4a - 4b]

[0128] The difference between Comparative Example 4a and Example 1 is that barium titanate particles (BTO - 90) with a relative permittivity of 90 are replaced with dielectric material particles (BTO - 30) with an A value of 30.

[0129] The difference between Comparative Example 4b and Example 1 is that barium titanate particles (BTO - 90) with a relative permittivity of 90 are replaced with dielectric material particles (BTO - 300) with an A value of 300. [Analysis and Detection]

[0130] 1. Initial Coulombic Efficiency (ICE) of the negative electrode In an environment of 25°C and normal pressure, the button battery was discharged at a constant current at a rate of 0.1C until the voltage reached 0.005V, and then discharged at a constant current at a rate of 0.05C until the voltage reached 0.005V. The discharge specific capacity in this case, that is, the initial lithium insertion capacity, was recorded. Subsequently, it was charged at a constant current at a rate of 0.1C until the voltage reached 1.5V, and the charge specific capacity in this case, that is, the initial lithium desorption capacity, was recorded. The button battery was subjected to 50 cycle charge-discharge tests according to the above method, and the lithium desorption capacity each time was recorded. Initial Coulomb efficiency (%) = Initial lithium desorption capacity / Initial lithium insertion capacity × 100%

[0131] 2. Charge resistance test In this application, the dynamic performance of the battery was evaluated by the 25°C 4C charge resistance. At 25°C, the lithium-ion batteries manufactured in the examples and comparative examples were discharged to 50% of their capacity, left standing for 30 min, the voltage value V1 was recorded, charged at a current A0 corresponding to a rate of 4C for 10 s, and the corresponding voltage value V2 at the end of charging was recorded. The calculation method for the charge resistance was R = (V2 - V1) / A0. The experimental results were normalized. The charge resistance value of Comparative Example 1 was taken as the reference value 100, and the examples were scaled up and down. (Charge cut-off voltage is 4.3V)

[0132] 3. Fast charge cycle life / cycles In this application, the capacity maintenance performance of the battery was evaluated by the fast charge cycle life / cycles. At 25°C, the lithium-ion batteries manufactured in the examples and comparative examples were charged at a rate of 2C and discharged at a rate of 1C, and a continuous cycle test in the 3% - 97% SOC range was carried out until the capacity of the lithium-ion battery became less than 80% of the initial capacity, and the number of cycles was recorded. (Charge cut-off voltage is 4.3V).

[0133]

Table 3

[0134] From the above experimental data, the following was found.

[0135] In Examples 1-3, it is crucial that the A value of the dielectric material particles is 50-200. Among them, A = [ε / (c / a)], where ε is the relative permittivity of the dielectric material particles, c is the length of the c-axis of the unit cell of the dielectric material particles, and a is the length of the a-axis of the unit cell of the dielectric material particles. Based on this form, the battery exhibits improved specific capacity, improved Coulomb efficiency at the first cycle, reduced charge resistance, and long cycle life.

[0136] The reason for the improved battery performance may be as follows.

[0137] In the high-current charge-discharge process of a battery (such as a lithium-ion battery), cations in the positive electrode film move to the interface between the positive electrode active material and the electrolyte. There is a solid electrolyte interface film (CEI film) on the surface of the positive electrode active material, and since the insertion / desorption barrier of solvated cations in the CEI film is high, some cations accumulate at the interface, resulting in concentration polarization. At the same time, due to the impedance of the CEI film, the migration speed of cations in the CEI film becomes slow, leading to a high discharge DCR and a reduction in the overall power output of the cell. When the dielectric material particles are excited by an electric field, the centers of positive and negative charges in the material are separated, and an internal reverse electric field is generated. The reverse electric field forms a triple-phase interface at the boundary of the electrolyte, dielectric material particles, and positive electrode active material. Since the triple-phase interface is thin, lithium ions can be inserted and desorbed quickly. When the range of the possible value of the A value of the dielectric material particles is 50-200, solvated lithium ions can be inserted and desorbed into the CEI film quickly.

[0138] Comparative Examples 1-3 do not contain dielectric material particles, and the battery could not exhibit the above-improved performance.

[0139] The A value of the dielectric material particles in Comparative Example 4a was too small, and the battery could not exhibit the above-improved performance.

[0140] The A value of the dielectric material particles in Comparative Example 4b was too large, and the battery could not exhibit the above-improved performance.

[0141] Also, in Examples 1 to 3, the ratio of the dielectric constant of the dielectric material particles to the dielectric constant of the electrolyte was 50 to 200:30 to 90. Within the above ratio range, the dielectric constant of the dielectric material particles and the dielectric constant of the electrolyte generated an impedance matching effect, and the secondary battery exhibited one or more improved performances such as an improved specific capacity, an improved Coulomb efficiency in the first cycle, a reduced charge resistance, and a long cycle life.

[0142] Note that the present application is not limited to the above embodiments. The above embodiments are merely examples, and embodiments having a configuration substantially the same as the technical idea within the scope of the technical means of the present application and exhibiting the same operational effects are all included in the technical scope of the present application. Also, without departing from the scope of the gist of the present application, various modifications conceivable by those skilled in the art can be added to the embodiments, and other embodiments constructed by combining some of the components in the embodiments are also included in the scope of the present application.

Explanation of Reference Numerals

[0143] 1 Battery Pack 2 Upper Housing 3 Lower Housing 4 Battery Module 5 Secondary Battery 51 Case 52 Electrode Assembly 53 Upper Cover Assembly 101 Positive Electrode Film Layer 102 Negative Electrode Film Layer 300 Separator 201 Positive Electrode Active Material 202 Dielectric Material Particles

Claims

1. A positive electrode material composition containing a positive electrode active material and dielectric material particles, wherein the A value of the dielectric material particles is 50 to 200, A = [ε / (c / a)], ε is the relative permittivity of the dielectric material particles, c is the length of the c-axis of the unit cell of the dielectric material particles, a is the length of the a-axis of the unit cell of the dielectric material particles, characterized in that it is a positive electrode material composition.

2. Having one or more of the following features, characterized in that it is the positive electrode material composition according to Claim 1. (1) The relative permittivity of the dielectric material particles is 50 to 200, (2) The length of the c-axis of the unit cell of the dielectric material particles is 0.3 nm to 0.5 nm, (3) The length of the a-axis of the unit cell of the dielectric material particles is 0.3 nm to 0.5 nm.

3. The dielectric material particles are one or more selected from barium titanate particles, lead titanate particles, lithium niobate particles, lead zirconate titanate particles, lead metaniobate particles, and lithium barium lead niobate particles, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 2.

4. The positive electrode active material is one or more selected from the following, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 3. (1) Layered oxide type positive electrode active material, (2) Spinel type positive electrode active material, (3) Polyanion type positive electrode active material.

5. The dielectric material particles are tetragonal barium titanate particles, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 4.

6. The volume median diameter of the dielectric material particles is 50 to 100 nm, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 5.

7. The volume median diameter of the positive electrode active material is 4 to 10 μm, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 6.

8. The ratio of the volume median diameter of the dielectric material particles to the positive electrode active material is 1:40 to 1:200, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 7.

9. The dielectric material particles adhere to the surface of the positive electrode active material, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 8.

10. The mass ratio of the dielectric material particles to the positive electrode active material is 1:100 to 10:100, characterized in that it is the positive electrode material composition according to any one of Claims 1 to 9.

11. Containing the positive electrode material composition according to any one of Claims 1 to 10, A positive electrode characterized by the above.

12. A secondary battery containing a positive electrode film layer and an electrolytic solution, wherein the positive electrode film layer contains the positive electrode material composition containing the positive electrode active material and the dielectric material particles according to any one of Claims 1 to 10, and the ratio of the relative permittivity of the dielectric material particles to that of the electrolytic solution is 50 to 200:30 to 90. A secondary battery characterized by the above.

13. An electrical device characterized by including the secondary battery according to Claim 12. An electrical device characterized by the above.

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