A battery and an electric device comprising the same

Abstract

The present application relates to a battery and a power utilization device comprising the battery, and belongs to the technical field of batteries. The battery of the present application comprises a positive electrode current collector and a positive electrode material located on at least one surface of the positive electrode current collector, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising olivine-type phosphate and lithium nickel cobalt manganese oxide, and the peak position difference a of the (131) crystal face in the XRD spectrum of the positive electrode sheet, the mass content b of the lithium nickel cobalt manganese oxide in the positive electrode material, and the ratio c of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material satisfy: 0.004 (c / 1.2) When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When 0.004 When

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery and an electric device comprising the battery. BACKGROUND

[0002] Olivine phosphate contains Mn ions, and the material has a high voltage platform and good lithium ion transmission performance. However, the ion conductivity of olivine phosphate is poor, and polarization easily occurs during the charge and discharge cycle, which causes serious dissolution of manganese ions and deterioration of the performance of olivine phosphate battery, especially the high-temperature performance. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art and provide a battery and an electric device comprising the battery to reduce the dissolution of Mn in olivine phosphate, so that the battery has good high-temperature performance, such as high-temperature storage performance and high-temperature cycle performance.

[0004] To achieve the above-mentioned purpose, in a first aspect, the present application provides a battery comprising a positive electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode material on at least one surface of the positive electrode current collector, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising olivine phosphate and lithium nickel cobalt manganese oxide, the battery satisfying:

[0005] 0.004≤a (c / 1.2) ·b≤0.190,

[0006] wherein a=a2-a1, a1 and a2 are the peak positions of the (131) crystal plane in the XRD spectrum of the positive electrode sheet at 20% SOC and 80% SOC of the battery, respectively, and the unit is °;

[0007] b is the mass content of lithium nickel cobalt manganese oxide in the positive electrode material, dimensionless;

[0008] c is the ratio of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material, dimensionless.

[0009] In a second aspect, the present application provides an electric device comprising the battery.

[0010] Compared with the prior art, the beneficial effects of the present application are: the present application can realize the balance of the polarization of olivine-type phosphate, the lithium ion diffusion barrier of NCM and the thermal stability of NCM by compounding olivine-type phosphate with ternary positive electrode materials and adjusting the peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive electrode sheet under the conditions of 80% SOC and 20% SOC of the battery, the mass content (b) of lithium nickel cobalt manganese oxide in the positive electrode material, and the intensity ratio (c) of the (003) diffraction peak and the (104) diffraction peak in the XRD spectrum of the positive electrode material to satisfy a specific relationship, so that the high-temperature performance of the battery such as high-temperature cycle performance and high-temperature storage performance is better. DETAILED DESCRIPTION

[0011] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some embodiments but not all embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0012] In the present application, the technical features described in an open form include a closed technical solution consisting of the listed features, and also an open technical solution containing the listed features.

[0013] In the present application, if no special description is made, the numerical range is regarded as continuous and includes the minimum value and the maximum value of the range and each value between the minimum value and the maximum value. Further, when the range refers to an integer, each integer between the minimum value and the maximum value of the range is included. In addition, when multiple ranges are provided to describe a feature or a characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0014] In the present application, the specific dispersion and stirring treatment method is not particularly limited.

[0015] The reagents or instruments used in the present application are not specified by the manufacturer, and are all conventional products that can be obtained by purchase.

[0016] Battery

[0017] The present application provides a battery, comprising a positive electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode material on at least one surface of the positive electrode current collector, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising olivine-type phosphate and lithium nickel cobalt manganese oxide (NCM), the battery satisfying:

[0018] 0.004≤a (c / 1.2)• b < 0.190,

[0019] wherein a = a2 - a1, a1, a2 are the peak positions of (131) crystal face in the XRD spectrum of the positive plate at the state of 20% SOC and 80% SOC of the battery, respectively, in °;

[0020] b is the mass content of nickel cobalt manganese lithium in the positive electrode material, dimensionless;

[0021] c is the intensity ratio of (003) diffraction peak to (104) diffraction peak in the XRD spectrum of the positive electrode material, dimensionless.

[0022] The incorporation of NCM in the olivine-type phosphate can take advantage of the high ionic conductivity of NCM to improve the overall ion migration rate of the material, making the lithium extraction of the olivine-type phosphate more smooth at each voltage platform, while also improving the uniformity of lithium extraction within the olivine-type phosphate material, reducing the stress of the olivine-type phosphate during lithium extraction, inhibiting the polarization of the olivine-type phosphate, reducing the risk of Mn element dissolution in the olivine-type phosphate, and being beneficial to improve the high-temperature performance of the battery, such as high-temperature storage and cycle performance. In addition, NCM has good structural stability under the action of Mn contained therein, ensuring that it can stably inhibit the polarization of the olivine-type phosphate during the charging and discharging cycle.

[0023] The diffraction peak of (131) crystal face is a characteristic peak of olivine-type phosphate, and the peak position represents the interplanar spacing. The inventors found that when the olivine-type phosphate structure is unstable, the peak position of (131) crystal face in the XRD spectrum of the positive plate at different SOC states of the battery will change, especially at the states of 80% SOC and 20% SOC of the battery. The peak position difference (a) of (131) crystal face in the XRD spectrum of the positive plate at the states of 80% SOC and 20% SOC of the battery can reflect the stability of the olivine-type phosphate structure. The smaller the value, the smaller the structural change of the olivine-type phosphate and the better the structural stability, but too strong stability of the olivine-type phosphate structure and too high crystallinity are not conducive to the capacity of the olivine-type phosphate.

[0024] The value of the peak position difference (a) of (131) crystal face in the XRD spectrum of the positive plate at the states of 80% SOC and 20% SOC of the battery can be adjusted by adjusting the type of carbon source in the carbon-coated olivine-type phosphate material, the calcination temperature, holding time and heating rate during carbon coating, and the type of doping elements in the olivine-type phosphate.

[0025] As to the method for detecting the peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive plate under the 80% SOC and 20% SOC states of the battery, the present application does not make any limitation, and those skilled in the art can detect the peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive plate under the 80% SOC and 20% SOC states of the battery according to the conventional technical means. For example, the peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive plate under the 80% SOC and 20% SOC states of the battery can be detected by the following method:

[0026] disassembling the battery under an inert atmosphere to obtain a positive plate, and performing XRD test on the obtained positive plate to record the peak position angle corresponding to the (131) crystal face, i.e. a1;

[0027] disassembling the battery under an inert atmosphere to obtain a positive plate, and performing XRD test on the obtained positive plate to record the peak position angle corresponding to the (131) crystal face, i.e. a1;

[0028] disassembling the battery under an inert atmosphere to obtain a positive plate, and performing XRD test on the obtained positive plate to record the peak position angle corresponding to the (131) crystal face, i.e. a1;

[0029] The specific test conditions of the XRD test are as follows: Cu target, scanning voltage of 40 KV, current of 40 mA, scanning range of 5-80°, scanning speed of 5° / min, and the XRD is calibrated by silicon internal standard method, and the XRD instrument can be Ultima IV of Japan Rigaku;

[0030] In the XRD spectrum, the diffraction peak at the diffraction angle 2θ of 35.5±0.5° is the (131) crystal face diffraction peak.

[0031] The mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material represents the addition amount of NCM in the positive electrode material, and the greater the value, the more the addition amount of NCM in the positive electrode material. When the addition amount of NCM in the positive electrode material is too small, the inhibitory effect of NCM on the polarization of the olivine-type phosphate is not obvious; when the addition amount of NCM in the positive electrode material is too large, it will lead to the decline of the thermal stability of the whole material system, which is not conducive to the high temperature performance.

[0032] The value of the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material can be regulated by adjusting the mass ratio of the olivine-type phosphate to the NCM, the proportion of the positive electrode active material in the positive electrode material, and the like.

[0033] As for the detection method of the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material, the present application is not limited, and the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material can be detected by the skilled person in the art according to the conventional technical means. For example, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material can be detected by the inductively coupled plasma (ICP) detection method, for example:

[0034] The battery is discharged to 2.5V at 0.33C, the positive electrode sheet is disassembled, then soaked in dimethyl carbonate (DMC), dried, the positive electrode material on the positive electrode sheet is scraped off for EDS energy spectrum (EDS, Energy Dispersive Spectrometer) test, under 15k magnification, the material morphology and size are observed, the element types and contents (normalized atomic percentage content) of the particles of different sizes in the field of view are tested in the EDS point scanning mode, similar particles are selected for testing at least 3 times to obtain accurate parallel sample test results, the material type is identified according to the data, and the average molar ratio of each type of transition metal element to the total transition metal element is obtained, that is, the chemical composition of each component of the positive electrode main material in the positive electrode sheet. Then, the sample is subjected to ICP detection (0.5g of the scraped positive electrode material powder is accurately weighed, dispersed in 20mL of water, 10mL of nitric acid (HNO3 mass percentage content is 66%) is added, and the dispersion is heated until the positive electrode material powder is completely dissolved, and then diluted with water to 100mL to obtain a test solution; the test solution is subjected to ICP test, and the ICP instrument working conditions are set as follows: gas flow 0.5L / min, power 1150W, ICP test), the corresponding chemical composition element concentration of the positive electrode active material (that is, the specific molar ratio of the chemical element) is confirmed; the molar ratio of each type of transition metal to the total metal in the positive electrode sheet is confirmed, the actual metal molar ratio of each type of material confirmed by the above EDS is combined, the mass ratio of the positive electrode material with a specific metal element to the total material is calculated as θ = ICP molar ratio / EDS molar ratio, and the mass ratio of the remaining other type of material is 1-θ, the mass ratio of the two positive electrode active materials is determined according to the chemical composition, and the mass content of each element in the olivine-type phosphate and the lithium nickel cobalt manganese oxide is also confirmed by the above method.

[0035] The ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material represents the degree of disorder of the NCM crystal structure, and a too large value indicates that the degree of disorder of the NCM crystal structure is too large, which will cause the cycle performance and thermal stability of the NCM material to be poor; and a too small value indicates that the NCM crystal structure is too ordered, thereby increasing the diffusion barrier of lithium ions and affecting the internal resistance of the material.

[0036] The value of the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material can be regulated by adjusting the content of manganese element in the lithium nickel cobalt manganese oxide, the preparation process parameters (such as calcination temperature, holding time, and heating rate) of the lithium nickel cobalt manganese oxide material, and the particle size of the lithium nickel cobalt manganese oxide.

[0037] As for the detection method of the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material, the present application does not make any limitation, and those skilled in the art can detect the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material according to conventional technical means. For example, the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material can be detected by the following method:

[0038] The battery is discharged at 0.33C to 2.5V, the positive electrode sheet is disassembled, the positive electrode sheet is soaked in DMC at room temperature for 60 min, taken out, dried, and the positive electrode material on the surface of the current collector is scraped off, the obtained positive electrode material is subjected to XRD test, the intensities of the diffraction peaks corresponding to the (003) crystal face and the (104) crystal face are recorded, that is, I(003) and I(104) are obtained, and then the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material is calculated;

[0039] The specific test conditions of the XRD test are as follows: Cu target, scanning voltage is 40KV, current is 40mA, scanning range is 5-80°, scanning speed is 2° / min, and the XRD is calibrated by silicon internal standard method, and the XRD instrument can be Ultima IV of Japan Rigaku.

[0040] In the XRD spectrum, the diffraction peak at the diffraction angle 2θ of 18.5±0.3° is the (003) crystal face diffraction peak, and the diffraction peak at the diffraction angle 2θ of 44.5±0.3° is the (104) crystal face diffraction peak.

[0041] The peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive plate of the battery in the 80% SOC and 20% SOC state, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive material, and the ratio (c) of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive material affect the high-temperature performance of the battery, such as the high-temperature cycle performance and the high-temperature storage performance, to different degrees. It is difficult to control a single variable to achieve good high-temperature performance of the battery, such as good high-temperature cycle performance and high-temperature storage performance. The application adjusts the battery in the 80% SOC and 20% SOC state. The peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive plate of the battery, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive material, and the ratio (c) of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive material satisfy the above specific relationship, realize the polarization and capacity of the olivine phosphate, the lithium ion diffusion barrier and the balance of the NCM thermal stability, and make the high-temperature performance of the battery, such as the high-temperature cycle performance and the high-temperature storage performance, better. The above relationship involves (c / 1.2) power of a, which indicates that there is a nonlinear coupling relationship between a and c, which reflects the adjustment effect of the crystal structure characteristics of NCM on the lattice parameter change of the olivine phosphate, and further illustrates the comprehensive influence of the interaction between the crystal structure characteristics and the lattice parameter change on the high-temperature performance of the battery.

[0042] For example, the value of a (c / 1.2) The value of b can be selected as 0.004, 0.006, 0.008, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.100, 0.110, 0.120, 0.130, 0.140, 0.150, 0.160, 0.170, 0.180, 0.190, or an interval range formed by any two of the above values.

[0043] In one preferred embodiment, the battery satisfies: 0.008≤a (c / 1.2) b≤0.036. Controlling a (c / 1.2) The value of b in this specific range better balances the polarization and capacity of the olivine phosphate, the lithium ion diffusion barrier and the NCM thermal stability, and further improves the high-temperature performance of the battery, such as the high-temperature cycle performance and the high-temperature storage performance.

[0044] In some embodiments, the peak position difference (a) of the (131) plane in the XRD spectrum of the positive electrode sheet at the 80% SOC and 20% SOC states of the battery ranges from 0.05° to 0.20°, such as 0.05°, 0.07°, 0.10°, 0.12°, 0.15°, 0.18°, 0.20°, or an interval range formed by any two of the above values.

[0045] In a preferred embodiment, the peak position difference (a) of the (131) plane in the XRD spectrum of the positive electrode sheet at the 80% SOC and 20% SOC states of the battery ranges from 0.10° to 0.15°.

[0046] When the peak position difference (a) of the (131) plane in the XRD spectrum of the positive electrode sheet at the 80% SOC and 20% SOC states of the battery ranges from 0.05° to 0.20°, especially from 0.10° to 0.15°, the olivine-type phosphate stability is more suitable, and the high-temperature performance of the battery such as high-temperature cycle performance and high-temperature storage performance is better.

[0047] In some embodiments, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material ranges from 0.01 to 0.5, such as 0.01, 0.03, 0.05, 0.07, 0.09, 0.10, 0.20, 0.30, 0.40, 0.50, or an interval range formed by any two of the above values.

[0048] In a preferred embodiment, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material ranges from 0.05 to 0.20.

[0049] When the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material ranges from 0.01 to 0.50, especially from 0.05 to 0.20, it is more conducive to balancing the polarization of the olivine-type phosphate and the thermal stability of the positive electrode material, and the high-temperature performance of the battery such as high-temperature cycle performance and high-temperature storage performance is better.

[0050] In some embodiments, the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material ranges from 0.5 to 1.8, such as 0.5, 0.7, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or an interval range formed by any two of the above values.

[0051] In a preferred embodiment, the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material ranges from 1.0 to 1.5.

[0052] When the ratio (c) of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material is in the range of 0.5-1.8, especially in the range of 1.0-1.5, the degree of disorder of the NCM is more appropriate, the cycle and thermal stability performance is good, the diffusion potential barrier of lithium ions is lower, and the high-temperature performance of the battery such as high-temperature cycle performance and high-temperature storage performance is better.

[0053] In some embodiments, the a1 is in the range of 35.0-35.9, such as 35.0, 35.1, 35.2, 35.3, 35.4, 35.5, 35.6, 35.7, 35.8, 35.9, or an interval range formed by any two of the above values. The size of the a1 value reflects the content of Mn in the olivine-type phosphate, and controlling the a1 value in the above appropriate range not only helps to improve the energy density of the battery, but also makes Mn more stable in the lithium-iron-manganese structure.

[0054] In some embodiments, the a2 is in the range of 35.2-36.0, such as 35.2, 35.3, 35.4, 35.5, 35.6, 35.7, 35.8, 35.9, 36.0, or an interval range formed by any two of the above values, so as to make the risk of Mn dissolution in the olivine-type phosphate lower.

[0055] In some embodiments, the lithium nickel cobalt manganese oxide has a general structure of: LiNi x Co y Mn z M (1-x-y-z) O2, wherein 0

[0056] The nickel cobalt manganese acid lithium can be free of coating material or coated with coating material on part or whole surface thereof, the present application does not limit the type of coating material in the nickel cobalt manganese acid lithium, for example, the coating material comprises at least one element selected from aluminum (Al), titanium (Ti), tungsten (W), boron (B), phosphorus (P), cobalt (Co), yttrium (Y), silicon (Si); meanwhile, the content of the coating material in the nickel cobalt manganese acid lithium is not limited, for example, the content of the coating material in the nickel cobalt manganese acid lithium is 500-5000 ppm, such as 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 4000 ppm, 4500 ppm, 5000 ppm or the interval range formed by any two of the above values.

[0057] In some embodiments, the particle size Dv50 of the nickel cobalt manganese acid lithium is 2.5-4.5 μm, such as 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm or the interval range formed by any two of the above values.

[0058] The present application does not limit the detection method of the particle size Dv50 of the nickel cobalt manganese acid lithium, and those skilled in the art can detect the particle size Dv50 of the nickel cobalt manganese acid lithium according to conventional technical means. For example, the particle size Dv50 test method of the nickel cobalt manganese acid lithium is as follows:

[0059] The battery after emptying the electricity is disassembled to obtain the positive plate, the positive plate is dried, the scraper is used to collect 0.1-0.2 g of positive material powder, the SEM (scanning electron microscope) is used to take pictures of the positive material powder, the particle size of the nickel cobalt manganese acid lithium in the positive material powder in the SEM picture is measured by MEARSURE NANO software, the diagonal line method is used to collect the particle size of the nickel cobalt manganese acid lithium, after collecting more than 100 samples, the particle size distribution is counted, and the particle size related parameters of the nickel cobalt manganese acid lithium, Dv50, are calculated.

[0060] In the present application, the preparation method of the nickel cobalt manganese acid lithium is not limited, and those skilled in the art can prepare the nickel cobalt manganese acid lithium according to conventional technical means. For example, the preparation method of the nickel cobalt manganese acid lithium comprises the following steps:

[0061] The nickel cobalt manganese acid lithium precursor and the lithium source are mixed and sintered to obtain the nickel cobalt manganese acid lithium.

[0062] The nickel cobalt manganese lithium precursor contains target stoichiometric ratios of Ni, Co and Mn (i.e. the ratio of the three elements in the nickel cobalt manganese lithium precursor is the same as the ratio of the three elements in the resulting nickel cobalt manganese lithium, and other similar expressions are similarly applicable), and the nickel cobalt manganese lithium precursor is one or more of oxides, hydroxides and carbonates of Ni, Co and Mn, for example the nickel cobalt manganese lithium precursor is a hydroxide of Ni, Co and Mn.

[0063] The nickel cobalt manganese lithium precursor can be obtained by methods known in the art, for example by a coprecipitation method, a gel method or a solid phase method. As an example, the preparation method of the nickel cobalt manganese lithium precursor comprises the following steps:

[0064] The Ni source, Co source and Mn source are dispersed in a solvent to obtain a mixed solution;

[0065] The obtained mixed solution, strong alkali solution and complexing agent solution are simultaneously pumped into a stirred reaction kettle, the pH value of the reaction solution is controlled to be 10-13, the temperature in the reaction kettle is controlled to be 25-90°C, and an inert gas (such as at least one of nitrogen and inert gas) is used to protect during the reaction; after the reaction is completed, the nickel cobalt manganese lithium precursor containing hydroxides of Ni, Co and Mn is obtained by aging, filtering, washing and vacuum drying.

[0066] In the process of preparing the nickel cobalt manganese lithium precursor, the Ni source used includes but is not limited to at least one of nickel sulfate, nickel nitrate, nickel chloride, nickel oxalate and nickel acetate;

[0067] And / or, the Co source used includes but is not limited to at least one of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt oxalate and cobalt acetate;

[0068] And / or, the Mn source used includes but is not limited to at least one of manganese sulfate, manganese nitrate, manganese chloride, manganese oxalate and manganese acetate;

[0069] And / or, the base in the strong alkali solution used includes but is not limited to at least one of sodium hydroxide and potassium hydroxide;

[0070] And / or, the complexing agent solution used includes but is not limited to ammonia.

[0071] In the process of preparing the nickel cobalt manganese lithium precursor, the amount of the Ni source, Co source and Mn source used can be selected to satisfy: Ni element molar amount: Co element molar amount: Mn element molar amount = (0.55-0.95): (0.03-0.15): (0.1-0.4).

[0072] The lithium source used in the preparation of the lithium nickel cobalt manganese oxide includes, but is not limited to, at least one of lithium oxide (Li2O), lithium phosphate (Li3PO4), lithium dihydrogen phosphate (LiH2PO4), lithium acetate (CH3COOLi), lithium hydroxide (LiOH), lithium carbonate (Li2CO3), lithium nitrate (LiNO3).

[0073] The lithium source used in the preparation of the lithium nickel cobalt manganese oxide and the amount of the ternary material precursor used satisfy the following ratio: the molar amount of Li element: the sum of the molar amounts of Ni, Co and Mn elements = (1-1.05):1.

[0074] The mixing of the lithium nickel cobalt manganese oxide precursor and the lithium source can be performed in a ball mill or a high-speed mixer.

[0075] In the preparation of the lithium nickel cobalt manganese oxide using the lithium nickel cobalt manganese oxide precursor, the sintering atmosphere is an inert atmosphere, such as nitrogen atmosphere, helium atmosphere or argon atmosphere.

[0076] In the preparation of the lithium nickel cobalt manganese oxide using the lithium nickel cobalt manganese oxide precursor, the sintering temperature can be selected to be 700-1000°C, and the sintering time can be selected to be 6-9h.

[0077] In addition, in the preparation of the lithium nickel cobalt manganese oxide precursor, a certain amount of a source of a doping element (if any) can be dispersed in a solvent together with the Ni source, the Co source and the Mn source to prepare the lithium nickel cobalt manganese oxide precursor, and the source of the doping element is at least one selected from an Al source, a W source, a Mg source, a Sr source, a Zr source, etc., so as to obtain the lithium nickel cobalt manganese oxide containing a certain amount of the doping element.

[0078] In the preparation of the lithium nickel cobalt manganese oxide, the lithium nickel cobalt manganese oxide can be coated as needed, specifically, a dry coating (high-temperature solid-phase method) is used to coat a coating material on the surface of the lithium nickel cobalt manganese oxide, and the surface of the lithium nickel cobalt manganese oxide is partially or entirely coated with a coating layer formed by the coating material. Exemplarily, the coating layer contains at least one element (hereinafter referred to as "coating element") selected from aluminum (Al), phosphorus (P), silicon (Si), titanium (Ti), tungsten (W), boron (B), cobalt (Co) or yttrium (Y).

[0079] In some embodiments, the olivine-type phosphate includes at least one of lithium manganese iron phosphate and doped lithium manganese iron phosphate.

[0080] In some embodiments, the molar content of manganese in the olivine-type phosphate accounts for 60%-85% of the total transition metal elements, such as 60%, 65%, 70%, 75%, 80%, 85% or a range formed by any two of the above values.

[0081] In some of these embodiments, the average primary particle size of the olivine-type phosphate ranges from 80 to 200 nm, such as 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, or the range formed by any two of the above values.

[0082] It should be noted that the average primary particle size of the olivine-type phosphate in the positive electrode active material of this application can be confirmed by the following method: disassemble the positive electrode sheet from the battery, then soak it in dimethyl carbonate (DMC), dry it, scrape off the positive electrode material on the positive electrode sheet for EDS energy spectrum test, use point scanning to identify olivine-type phosphate and layered lithium nickel cobalt manganese oxide particles under a magnified view, obtain the particle morphology of the olivine-type phosphate in three regions under a scanning electron microscope with a magnification of 30k, measure the diagonal length of the primary particles of the olivine-type phosphate through nanomeasurer software, test 80 samples, and count the results of the three regions, which is the average primary particle size of the olivine-type phosphate.

[0083] In some of these embodiments, the chemical formula of lithium iron manganese phosphate is LiMn d Fe 1-d PO4, where 0 < d < 1. d can be selected as 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, 0.99, or the range formed by any two of the above values. The lithium iron manganese phosphate can either contain no doping elements or contain doping elements. The present invention does not limit the type of doping elements in the lithium iron manganese phosphate. For example, the doping elements include but are not limited to at least one of V, W, Ti, and Mg. At the same time, the present invention also does not limit the content of the doping elements in the lithium iron manganese phosphate. Exemplarily, the content of the doping elements in the lithium iron manganese phosphate is 500 - 2000 ppm. The lithium iron manganese phosphate can either contain no coating material or be coated with a coating material on some or all of its surfaces. The present invention does not limit the type of coating material in the lithium iron manganese phosphate. For example, the coating material includes at least one of graphene and carbon nanotubes. At the same time, the present invention also does not limit the content of the coating material in the lithium iron manganese phosphate. Exemplarily, the content of the coating material in the lithium iron manganese phosphate is 1.5 - 2.5 wt%, such as 1.5 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.5 wt%, or the range formed by any two of the above values.

[0084] In the present invention, the preparation method of the olivine-type phosphate is not limited, and those skilled in the art can prepare the olivine-type phosphate according to conventional technical means. Exemplarily, the preparation method of the olivine-type phosphate includes the following steps:

[0085] mixing a manganese source, an iron source, a phosphorus source, a lithium source and a solvent, and reacting at 140-160°C for 8-12h to obtain an olivine-type phosphate precursor;

[0086] dispersing the obtained olivine-type phosphate precursor and a carbon source in a solvent, and spray-drying the obtained mixture, and then calcining under a protective atmosphere to obtain the olivine-type phosphate.

[0087] For example, in the process of preparing the olivine-type phosphate, the manganese source used includes but is not limited to at least one of trimanganese tetroxide, manganese nitrate, manganese carbonate, manganese oxalate, manganese sulfate, manganese chloride, and manganese acetate.

[0088] For example, the iron source used includes but is not limited to at least one of ferrous sulfate, iron phosphate, ferrous phosphate, iron hydroxide, ferrous hydroxide, iron carbonate, ferrous carbonate, iron acetate, ferrous acetate, ferric oxide, ferriferrous oxide, ferrous oxalate, and iron oxalate.

[0089] For example, the phosphorus source used includes but is not limited to at least one of phosphoric acid, lithium dihydrogen phosphate, lithium phosphate, diammonium hydrogen phosphate, and ammonium phosphate.

[0090] For example, the lithium source used includes but is not limited to at least one of lithium hydroxide, lithium dihydrogen phosphate, lithium phosphate, lithium carbonate, lithium nitrate, lithium oxalate, lithium citrate, and lithium acetate.

[0091] For example, the solvent used includes but is not limited to water.

[0092] For example, the carbon source used includes but is not limited to at least one of glucose (GLC), sucrose, polyethylene glycol (PEG), and polyvinyl alcohol. For example, in the process of preparing the manganese iron lithium phosphate precursor, the molar ratio of the manganese source, the iron source, and the phosphorus source used is (0.6-0.85):(0.15-0.4):(1.02-1.05).

[0093] For example, the protective atmosphere is an inert atmosphere, such as a nitrogen atmosphere.

[0094] For example, the calcination temperature can be selected to be 550-680°C, such as 550°C, 600°C, 650°C, 680°C, or a range formed by any two of the above values.

[0095] For example, the calcination time is 4-10h, such as 6h, or a range formed by any two of the above values.

[0096] In the process of preparing the olivine-type phosphate, a doping element raw material can also be used, for example, when dispersing the olivine-type phosphate precursor and a carbon source in a solvent, a doping element raw material can also be dispersed together, and then spray-dried and calcined under a protective atmosphere to obtain the olivine-type phosphate. Exemplarily, the doping element raw material includes, but is not limited to, at least one of a V source, a W source, a Ti source, and a Mg source.

[0097] In some embodiments, the mass content of the olivine-type phosphate in the positive electrode material is in the range of 0.46-0.95, such as 0.46, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, or a range formed by any two of the above values.

[0098] In some embodiments, the mass content of the positive electrode active material in the positive electrode material is in the range of 0.95-0.985, such as 0.950, 0.965, 0.970, 0.980, 0.985, or a range formed by any two of the above values.

[0099] In addition to the positive electrode active material described above, the positive electrode material further comprises a positive electrode conductive agent and a positive electrode binder.

[0100] The positive electrode conductive agent is used to provide conductivity, and any conductive agent can be used without particular limitation, as long as it has suitable electronic conductivity and does not significantly cause adverse chemical changes in the battery. Exemplarily, the positive electrode conductive agent includes, but is not limited to, at least one of carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, and fullerenes, wherein the carbon fibers are, for example, carbon nanofibers and the like; the carbon black is, for example, SP (Super P, same below), acetylene black, Ketjen black, and the like.

[0101] In some embodiments, the mass content of the positive electrode conductive agent in the positive electrode material is in the range of 0.01-0.04, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, or a range formed by any two of the above values.

[0102] The positive electrode binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the positive electrode current collector, and any binder can be used without particular limitation, as long as it has suitable binder properties and does not significantly cause adverse chemical changes in the battery. Exemplarily, the positive electrode binder includes, but is not limited to, fluorine-containing polyolefin-based binders, which include, but are not limited to, polyvinylidene fluoride (PVDF), a polyvinylidene fluoride copolymer, or a modified (for example, carboxylic acid, acrylic acid, acrylonitrile, and the like) derivative thereof, and the like.

[0103] In some embodiments, the mass content of the cathode binder in the cathode material is 0.01-0.04, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, or a range formed by any two of the above values.

[0104] The cathode material can be located on one side of the cathode current collector or on both sides of the cathode current collector.

[0105] The cathode current collector is not particularly limited in the present application, as long as it has electrical conductivity and does not cause adverse chemical changes in the battery, and can use, for example: aluminum, nickel, titanium, stainless steel, baked carbon; or aluminum or stainless steel surface treated with one of carbon, nickel, titanium, silver, etc.

[0106] The cathode sheet of the present application can be prepared according to conventional methods in the art. For example, the cathode active material, the cathode conductive agent and the cathode binder are dispersed in a solvent to obtain a cathode slurry, and then the cathode slurry is coated on at least one side of the cathode current collector, and after drying, rolling, slitting and other processes, the cathode sheet is obtained. The solvent used to prepare the cathode slurry includes but is not limited to at least one of N-methyl pyrrolidone (NMP), deionized water.

[0107] Battery

[0108] The present application also provides a battery comprising the cathode sheet, the anode sheet and the electrolyte.

[0109] The anode sheet of the present application comprises an anode current collector and a cathode material located on at least one surface of the anode current collector, wherein the anode material comprises an anode active material.

[0110] The anode active material is not particularly limited in the present application. Illustratively, the anode active material includes but is not limited to natural graphite, artificial graphite, mesophase carbon microbeads (MCMB), hard carbon, soft carbon, silicon, SiO f (0 < f < 2, such as f = 1), silicon-carbon, Li4Ti5O 12 , or a range formed by any two of the above values.

[0111] In some embodiments, the anode active material comprises graphite, and the average particle diameter of the graphite is 8-13 μm, such as 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, or a range formed by any two of the above values.

[0112] The detection method of the average particle diameter of the graphite is not limited in the present application, and the average particle diameter of the graphite can be detected by the skilled person in the art according to conventional technical means. Illustratively, the average particle diameter of the graphite is tested as follows:

[0113] The secondary battery in the empty state was disassembled, and the negative electrode sheet obtained was scraped to obtain powder. The powder was then tested according to the test method for D50 in the national standard GB / T 24533-2019.

[0114] In some embodiments, the mass content of the negative electrode active material in the negative electrode material is 0.93-0.98, such as 0.93, 0.95, 0.97, 0.98, or an interval range formed by any two of the above values.

[0115] The negative electrode active material layer can further comprise a negative electrode conductive agent and / or a negative electrode binder.

[0116] The negative electrode conductive agent is used to provide conductivity, and any conductive agent can be used without particular limitation, as long as it has suitable electronic conductivity and does not significantly cause adverse chemical changes in the battery. Illustratively, the negative electrode conductive agent includes, but is not limited to, at least one of carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, fullerenes, and the like, wherein the carbon fibers are, for example, carbon nanofibers and the like; the carbon black is, for example, SP, acetylene black, Ketjen black, and the like.

[0117] In some embodiments, the mass content of the negative electrode conductive agent in the negative electrode material is 0.01-0.05, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, or an interval range formed by any two of the above values.

[0118] The negative electrode binder is used to improve the adhesion between the negative electrode active material particles and the adhesion between the negative electrode active material and the negative electrode current collector, and any binder can be used without particular limitation, as long as it has suitable binder properties and does not significantly cause adverse chemical changes in the battery. Illustratively, the negative electrode binder includes, but is not limited to, fluorine-containing polyolefin-based binders, which include, but are not limited to, polyvinylidene fluoride (PVDF), vinylidene fluoride copolymers, or modified (e.g., carboxylic acid, acrylic acid, acrylonitrile, etc.) derivatives thereof, and the like.

[0119] In some embodiments, the mass content of the negative electrode binder in the negative electrode material is 0.01-0.05, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, or an interval range formed by any two of the above values.

[0120] The negative electrode material can be located on one side of the positive electrode current collector or on both sides of the negative electrode current collector.

[0121] The negative current collector is not particularly limited as long as it has conductivity and does not cause adverse chemical changes in the battery, and examples include copper, stainless steel, aluminum, nickel, titanium, baked carbon, copper or stainless steel surface-treated with at least one of carbon, nickel, titanium, silver, or the like, or an aluminum-cadmium alloy.

[0122] The electrolyte solution can be selected from various electrolyte solutions suitable for batteries in the art. The electrolyte solution includes an electrolyte and a solvent, and the electrolyte can generally include a lithium salt.

[0123] Examples of the lithium salt include, but are not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium bisoxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be selected to be 0.9 to 2.0 mol / L.

[0124] Examples of the solvent include, but are not limited to, at least one of ethylene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate (PC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE). The mass content of the solvent in the electrolyte solution can be selected to be 0.55 to 0.92.

[0125] In addition, the electrolyte solution can further include an additive. Examples of the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and an additive capable of improving certain properties of the battery, such as an additive for improving high-temperature properties of the battery, an additive for improving overcharge properties of the battery, an additive for improving low-temperature properties of the battery, and the like.

[0126] The battery can further include a separator between the positive electrode sheet and the negative electrode sheet for spacing the positive electrode sheet and the negative electrode sheet to prevent the positive electrode sheet and the negative electrode sheet from contacting and short-circuiting. The separator can be any of various separator materials suitable for use in batteries in the art. Illustratively, the separator includes, but is not limited to, at least one of polypropylene, polyethylene.

[0127] Electric device

[0128] The present application further provides an electric device comprising the battery. The battery serves as a power supply for the electric device.

[0129] The electric device refers to any device that can utilize electric energy and convert it into mechanical energy, thermal energy, light energy, or other one or more forms of energy, such as an electric motor, an electric heating device, an electric light source, etc. Specifically, it can be, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship and a satellite, an energy storage system, etc. The mobile device can be a mobile phone, a notebook computer, a drone, a robot vacuum cleaner, an electronic cigarette, etc. The electric vehicle can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.

[0130] The present application is further described below with specific examples. It should be noted that the sintering below is performed in air unless otherwise specified:

[0131] Example 1

[0132] This example provides a lithium ion battery, and the specific preparation method is as follows:

[0133] (1) Preparation of the positive electrode sheet

[0134] Preparation of olivine-type phosphate lithium manganese iron phosphate: MnSO4, FeSO4, H3PO4 are mixed uniformly according to a molar ratio of 6:4:10, and then mixed with water to prepare a mixed solution with a transition metal element concentration of 1M. Subsequently, ascorbic acid and LiOH are added, wherein the amount of ascorbic acid added is 0.2% of the total molar amount of MnSO4, FeSO4, and H3PO4, and the amount of LiOH added is 3 times the molar amount of H3PO4. The obtained mixture is stirred at 70°C for 6h, then pressurized and heated to 150°C for 10h. The solid is separated and dried, then the obtained powder is dispersed in water, and a carbon source of 21wt% of the mass of the powder is added. Spray drying is performed, and finally calcination is performed at 800°C under a nitrogen atmosphere for t h to obtain carbon-coated lithium manganese iron phosphate.

[0135] Wherein the value of t and the selection of the carbon source are shown in Table 1.

[0136] Preparation of lithium-containing oxide lithium nickel cobalt manganese oxide: nickel acetate, cobalt acetate, manganese acetate and sodium hydroxide were mixed and dissolved uniformly in water according to a molar ratio of 6:1:3:10, and reacted at 80°C for 24h. The obtained solid precursor with an average particle size of 3.5μm was mixed uniformly with lithium hydroxide according to a metering ratio, and then calcined at n°C for 8h in an air atmosphere to obtain lithium nickel cobalt manganese oxide.

[0137] wherein n is as shown in Table 1.

[0138] Preparation of positive electrode sheet: the obtained olivine-type phosphate and NCM were mixed according to the ratio in Table 1 to serve as positive electrode active material. The positive electrode active material, binder PVDF and conductive agent SP were mixed according to a mass ratio of 97:2:1, dispersed in NMP to obtain positive electrode slurry. The positive electrode slurry was coated on both sides of aluminum foil, and then subjected to rolling and cutting to obtain positive electrode sheet.

[0139] (2) Preparation of negative electrode sheet

[0140] The negative electrode active material artificial graphite with a particle size of 12μm, conductive agent SP and binder CMC were mixed according to a mass ratio of 96.4:1:2.6, dispersed in deionized water to obtain negative electrode slurry. The negative electrode slurry was coated on both sides of copper foil, and then subjected to drying, rolling and cutting to obtain negative electrode sheet.

[0141] (3) Preparation of electrolyte

[0142] Vinyl carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) were mixed according to a volume ratio of 1:1:1 to obtain mixed organic solvent. Dry lithium salt LiPF6 was dissolved in the above mixed organic solvent to prepare electrolyte with a LiPF6 concentration of 1mol / L.

[0143] (4) Preparation of separator

[0144] Polyethylene (PE) separator was used.

[0145] (5) Assembly and formation

[0146] The above positive electrode sheet, separator and negative electrode sheet were stacked in order, with the separator between the positive and negative electrode sheets to play a separating role, and then wound to obtain bare battery cell. The bare battery cell was placed in an outer packaging shell, dried, and then injected with electrolyte. After vacuum packaging, standing, formation and shaping processes, lithium ion battery was obtained.

[0147] Examples 2-27 and Comparative Examples 1-2

[0148] These examples and comparative examples all provided a lithium ion battery, and the preparation method was close to that of Example 1, with the difference being that:

[0149] When preparing the olivine-type lithium iron manganese phosphate, the molar ratio of MnSO4, FeSO4 and H3PO4 is adjusted according to the chemical formula of lithium iron manganese phosphate, and the chemical formula of lithium iron manganese phosphate, the value of t and the selection of carbon source are shown in Table 1.

[0150] When preparing the lithium-containing oxide lithium nickel cobalt manganese oxide, the ratio of the sum of the molar amounts of nickel acetate, cobalt acetate and manganese acetate to the molar amount of sodium hydroxide is fixed, and the molar ratio of nickel acetate, cobalt acetate and manganese acetate is adjusted according to the chemical formula of lithium nickel cobalt manganese oxide, and the chemical formula of lithium nickel cobalt manganese oxide and the value of n are shown in Table 1.

[0151] When preparing the positive electrode sheet, the mass ratio of the positive electrode active material (i.e. the positive electrode main material) to the binder and the conductive agent is shown in Table 1.

[0152] Table 1

[0153]

[0154]

[0155]

[0156] The peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive electrode sheet at the 80% SOC and 20% SOC states of the battery, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material and the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the positive electrode material in each of the examples and the comparative examples were detected by the above method, and the test results are shown in Table 2.

[0157] The lithium ion batteries in each of the examples and the comparative examples were subjected to performance tests, and the test results are shown in Table 2, and the specific test methods are as follows:

[0158] High-temperature cycle performance test: after the lithium ion battery was placed at 45℃ for 120 min, the charging and discharging was carried out according to the following procedure: 1C constant current constant voltage full charging, cut-off voltage 4.25V, cut-off current 0.33C, standing for 20 min, and then 1C constant current discharging to 2.5V; the above charging and discharging was one cycle, and the cycle charging and discharging was carried out, the initial first cycle 1C discharging capacity was taken as the initial first cycle discharging capacity, and the ratio of the discharging capacity after 1C charging and discharging for 100 cycles to the initial first cycle discharging capacity was taken as the capacity retention rate of the battery after 100 cycles at high temperature;

[0159] High-temperature storage performance test: 25℃, 0.33C constant current and constant voltage full charge, cut-off voltage 4.25V, cut-off current 0.33C, stand for 20min, then 0.33C constant current discharge to 2.5V, the above is a cycle, cycle twice, take the second capacity e, 25℃, 0.33C constant current and constant voltage full charge, cut-off voltage 4.25V, cut-off current 0.33C. The battery is transferred to a 60℃ oven for 7 days, then transferred to a 25℃ oven for 4h, 25℃, 0.33C constant current discharge to 2.5V, take the capacity f, then 0.33C constant current and constant voltage full charge, cut-off voltage 4.25V, cut-off current 0.33C, stand for 20min, then 0.33C constant current discharge to 2.5V, take the capacity g. f / e is the capacity retention rate after storage, g / e is the capacity recovery rate after storage.

[0160] Table 2

[0161]

[0162]

[0163] The capacity retention rates of the batteries prepared in the embodiments of the present application after 45℃, 1C, 100 cycles are all ≥90%, the capacity retention rates after 60℃ storage for 7 days are all ≥83%, and the capacity recovery rates after 60℃ storage for 7 days are all ≥80%, which shows that the batteries containing the positive electrode sheets of the present application have excellent high-temperature cycle and storage performance.

[0164] From the comparison of Examples 1-7 and Comparative Examples 8-13, and the comparison of Examples 14-15 and Comparative Examples 16-21, it can be seen that when the peak position difference (a) of the (131) crystal face in the XRD spectrum of the positive electrode sheet, the mass content (b) of the lithium nickel cobalt manganese oxide in the positive electrode material, and the ratio (c) of the intensity of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material at 80% SOC and 20% SOC of the battery meet the preferred ranges described in the present application, the high-temperature cycle and storage performance of the battery is relatively better.

[0165] From the comparison of Examples 1-7 and Comparative Examples 14-15, and the comparison of Examples 8-13 and Comparative Examples 16-21, it can be seen that when the battery meets 0.008≤a (c / 1.2) When b≤0.036, the high-temperature cycle and storage performance of the battery is relatively better.

[0166] From the comparison of Examples 1-7 and Comparative Examples 14-15, and the comparison of Examples 8-13 and Comparative Examples 16-21, it can be seen that when the battery meets 0.008≤a (c / 1.2)• When the value of b exceeds the range of 0.004-0.190, both the high-temperature cycle and storage performance of the battery are poor.

[0167] Finally, it should be noted that the above examples are only used to illustrate the technical solutions herein and are not intended to limit the scope of protection herein. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions herein can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions herein.

Claims

1. A battery, characterized in that, The battery includes a positive electrode sheet, the positive electrode sheet comprising a positive current collector and a positive electrode material located on at least one surface of the positive current collector, the positive electrode material comprising a positive electrode active material, the positive electrode active material comprising olivine phosphate and lithium nickel cobalt manganese oxide, and the battery satisfies the following: 0.004≤a (c / 1.2) ·b≤0.190, Where a = a2 - a1, a1 and a2 are the peak positions of the (131) crystal plane in the XRD spectrum of the positive electrode sheet under the conditions of 20% SOC and 80% SOC of the battery, respectively, in °; b represents the mass content of lithium nickel cobalt manganese oxide in the cathode material, which is dimensionless; c is the ratio of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak in the XRD spectrum of the cathode material, which is dimensionless.

2. The battery as described in claim 1, characterized in that, The battery satisfies: 0.008 ≤ a (c / 1.2) b≤0.

036.

3. The battery as described in claim 1, characterized in that, The range of 'a' is 0.05° to 0.20°.

4. The battery as described in claim 3, characterized in that, The range of 'a' is 0.10° to 0.15°.

5. The battery as described in claim 1, characterized in that, The range of b is 0.01 to 0.

50.

6. The battery as described in claim 5, characterized in that, The range of b is 0.05 to 0.

20.

7. The battery as claimed in claim 1, characterized in that, The range of c is 0.5 to 1.

8.

8. The battery as claimed in claim 7, characterized in that, The range of c is 1.0 to 1.

5.

9. The battery as claimed in claim 1, characterized in that, At least one of the following conditions must be met: S1. The range of a1 is 35.0 to 35.9; S2. The range of a2 is 35.2 to 36.0; S3. The general structural formula of the lithium nickel cobalt manganese oxide is: LiNi x Co y Mn z M (1-x-y-z) O2, where 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 ≤ 1 - xyz < 1, and x / y ranges from 4.5 to 7; M is a dopant element selected from at least one of Al, W, Mg, Sr, and Zr; S4. The olivine-type phosphate includes at least one of lithium manganese iron phosphate and doped lithium manganese iron phosphate; S5. The manganese element accounts for 60% to 85% of the total transition metal elements in the olivine-type phosphate; S6. The average primary particle size range of the olivine-type phosphate is 80–200 nm; S7. The particle size Dv50 of the lithium nickel cobalt manganese oxide ranges from 2.5 to 4.5 μm; S8. The mass content of the olivine-type phosphate in the cathode material ranges from 0.46 to 0.

95. S9. The battery further includes a negative electrode sheet, which includes a negative electrode active material; the negative electrode active material includes graphite, and the average particle diameter of the graphite is 8 to 13 μm.

10. An electrical device, characterized in that, It includes the battery as described in any one of claims 1 to 9.

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