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

[0001] This application is a divisional application of application number CN 202510416073.7, filed on April 3, 2025, entitled "A Battery and an Electrical Device Containing the Battery". Technical Field

[0002] This invention relates to the field of battery technology, and more particularly to a battery and an electrical device comprising the battery. Background Technology

[0003] Olivine-type phosphates contain Mn ions, resulting in a high voltage plateau and good lithium-ion transport performance. However, olivine-type phosphates have poor ionic conductivity and are prone to polarization during charge-discharge cycles, leading to severe dissolution of manganese ions and deterioration of the performance of olivine-type phosphate batteries, especially at high temperatures. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a battery and an electrical device containing the battery to reduce the dissolution of Mn in olivine phosphate and enable the battery to have good high-temperature performance, such as high-temperature storage performance and high-temperature cycling performance.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a battery comprising 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, the battery satisfying:

[0006] 0.004≤a (c / 1.2) ·b≤0.190,

[0007] 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 °;

[0008] b represents the mass content of lithium nickel cobalt manganese oxide in the cathode material, which is dimensionless;

[0009] 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.

[0010] Secondly, the present invention provides an electrical device including the battery.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention combines olivine phosphate with ternary cathode material and adjusts the peak position difference (a) of the (131) crystal plane in the XRD spectrum of the cathode sheet at 80% SOC and 20% SOC of the battery, the mass content of lithium nickel cobalt manganese oxide in the cathode material (b), and the intensity ratio (c) of the (003) diffraction peak and (104) diffraction peak in the XRD spectrum of the cathode material to satisfy a specific relationship, thereby achieving a balance between the polarization of olivine phosphate, the lithium-ion diffusion barrier of NCM and the thermal stability of NCM, and making the high-temperature performance of the battery, such as high-temperature cycle performance and high-temperature storage performance, better. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0014] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0015] In this invention, there are no particular limitations on the specific dispersion and stirring methods.

[0016] Unless otherwise specified, all reagents or instruments used in this invention are commercially available products.

[0017] Battery

[0018] This invention provides a battery comprising a positive electrode sheet, the positive electrode sheet including 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 including olivine phosphate and lithium nickel cobalt manganese oxide (NCM), the battery satisfying:

[0019] 0.004≤a (c / 1.2)·b≤0.190,

[0020] 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 °;

[0021] b represents the mass content of lithium nickel cobalt manganese oxide in the cathode material, which is dimensionless;

[0022] 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.

[0023] Incorporating NCM into olivine phosphates can improve the overall ion migration rate of the material by utilizing the high ionic conductivity of NCM. This makes lithium insertion / extraction from olivine phosphates smoother across various voltage levels. Simultaneously, it can improve the uniformity of lithium insertion / extraction within the olivine phosphate material, reduce stress during the process, suppress polarization, and lower the risk of Mn dissolution. This is beneficial for improving the high-temperature performance of the battery, such as high-temperature storage and cycle performance. Furthermore, the Mn content of NCM contributes to its good structural stability, ensuring its stable suppression of polarization during charge-discharge cycles.

[0024] (131) The diffraction peaks of the crystal plane are characteristic peaks of olivine phosphate. The peak position represents the interplanar spacing. The inventors found that when the olivine phosphate structure is unstable, the peak position of the (131) crystal plane in the XRD pattern of the positive electrode under different battery SOC states will change, especially at 80% SOC and 20% SOC states. The peak position difference (a) of the (131) crystal plane in the XRD pattern of the positive electrode under 80% SOC and 20% SOC states can reflect the stability of the olivine phosphate structure. The smaller the value, the smaller the structural change of the olivine phosphate as charging and discharging proceeds, and the better the structural stability. However, if the stability of the olivine phosphate structure is too strong and the crystallinity is too high, it will be detrimental to its capacity.

[0025] The value of the peak position difference (a) of the crystal plane (131) in the XRD spectrum of the positive electrode sheet under 80% SOC and 20% SOC conditions can be adjusted by adjusting the type of carbon source in the olivine phosphate carbon coating material, the calcination temperature, holding time and heating rate during the carbon coating process, and the type of dopant element in the olivine phosphate.

[0026] The present invention does not limit the method for detecting the peak position difference (a) of the crystal plane (131) in the XRD pattern of the positive electrode sheet under 80% SOC and 20% SOC conditions. Those skilled in the art can detect the peak position difference (a) of the crystal plane (131) in the XRD pattern of the positive electrode sheet under 80% SOC and 20% SOC conditions using conventional techniques. For example, the peak position difference (a) of the crystal plane (131) in the XRD pattern of the positive electrode sheet under 80% SOC and 20% SOC conditions can be detected by the following method:

[0027] The battery was discharged to 2.5V at 0.33C, then charged to 4.25V at 0.33C, and discharged to 2.5V at 0.33C. The discharge capacity was recorded as C1. The charge was adjusted to 0.2 times the C1 state by charging at 0.33C, which was recorded as 20% SOC. The positive electrode was obtained by disassembling under an inert atmosphere. The obtained positive electrode was subjected to XRD test, and the peak angle corresponding to the (131) crystal plane was recorded as a1.

[0028] The battery was discharged to 2.5V at 0.33C, then charged to 4.25V at 0.33C, and discharged to 2.5V at 0.33C. The discharge capacity was recorded as C1. The charge was adjusted to 0.8 times the C1 state by charging at 0.33C, which was recorded as 80% SOC. The positive electrode was obtained by disassembling under an inert atmosphere. The obtained positive electrode was subjected to XRD test, and the peak angle corresponding to the (131) crystal plane was recorded as a2.

[0029] Then, the peak position difference (a) of the crystal plane (131) in the XRD spectrum of the positive electrode sheet under the conditions of 80% SOC and 20% SOC of the battery was calculated.

[0030] The specific test conditions for XRD testing are as follows: Cu target, scanning voltage of 40KV, current of 40mA, scanning range of 5-80°, scanning speed of 5° / min, XRD is calibrated by silicon internal standard method, and the XRD instrument used can be the Ultima IV from Rigaku, Japan.

[0031] In the XRD pattern, the diffraction peak at the position where the diffraction angle 2θ is 35.5±0.5° is the (131) crystal plane diffraction peak.

[0032] The mass content (b) of lithium nickel cobalt manganese oxide in the cathode material represents the amount of NCM added to the cathode material. The larger the value, the more NCM is added to the cathode material. When the amount of NCM added to the cathode material is too small, the inhibitory effect of NCM on olivine phosphate polarization is not obvious; when the amount of NCM added to the cathode material is too large, it will lead to a decrease in the thermal stability of the entire material system, which is detrimental to high-temperature performance.

[0033] The mass content (b) of lithium nickel cobalt manganese oxide in the cathode material can be controlled by adjusting the mass ratio of olivine phosphate to NCM and the proportion of cathode active material in the cathode material.

[0034] The present invention does not limit the method for detecting the mass content (b) of lithium nickel cobalt manganese oxide in the cathode material. Those skilled in the art can detect the mass content (b) of lithium nickel cobalt manganese oxide in the cathode material using conventional techniques. For example, the mass content (b) of lithium nickel cobalt manganese oxide in the cathode material can be measured by inductively coupled plasma (ICP) detection, for example:

[0035] The battery was discharged to 2.5V at 0.33C, and the positive electrode sheet was disassembled. It was then soaked in dimethyl carbonate (DMC), dried, and the positive electrode material on the positive electrode sheet was scraped off for EDS (Energy Dispersive Spectrometer) testing. The morphology and size of the material were observed at 15k magnification. The elemental types and contents (normalized atomic percentages) of particles of different shapes and sizes in the field of view were tested using EDS point-scan signal acquisition. At least three similar particles were selected for testing to obtain accurate parallel sample test results. The material type was identified based on this data, and the average molar ratio of each transition metal element to the total transition metal elements was obtained, which is the chemical composition of each component of the positive electrode main material in the electrode sheet. Subsequently, the sample was subjected to ICP testing (0.5g of the scraped positive electrode material powder was accurately weighed, dispersed in 20mL of water, and then 10mL of nitric acid (HNO3 mass percentage of 66%) was added. The mixture was dispersed and heated until the positive electrode material powder was completely dissolved, and then diluted to 100mL with water to obtain the test solution; the test solution was subjected to ICP testing, and the ICP instrument operating conditions were set as follows: gas flow rate 0.5L / min, power 1150W, to confirm the corresponding chemical composition element concentration of the positive electrode active material (i.e., the specific molar percentage of chemical elements); the molar ratio of various transition metals in the electrode sheet was confirmed. Combined with the actual metal molar ratio of various materials confirmed by EDS, the mass ratio of the positive electrode material with a specific metal element to the total material was calculated as θ = ICP molar ratio / EDS molar ratio. The mass ratio of the remaining other types of materials was 1-θ. The mass ratio of the two positive electrode active materials was determined according to the chemical composition. At the same time, the mass content of each element in the olivine phosphate and lithium nickel cobalt manganese oxide was also confirmed by the above methods.

[0036] In the XRD spectrum of the cathode material, the ratio (c) of the intensity of the (003) diffraction peak to the intensity of the (104) diffraction peak represents the degree of disorder in the NCM crystal structure. If the value is too large, it indicates that the NCM crystal structure is too disordered, which will lead to a deterioration in the cycle performance and thermal stability of the NCM material. If the value is too small, it 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.

[0037] The value of (c) in the intensity ratio of (003) diffraction peak to (104) diffraction peak in the XRD spectrum of the cathode material can be controlled by adjusting the content of manganese in lithium nickel cobalt manganese oxide, the preparation process parameters of lithium nickel cobalt manganese oxide material (such as calcination temperature, holding time, heating rate), and the particle size of lithium nickel cobalt manganese oxide.

[0038] The present invention does not limit the method for detecting the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD pattern of the cathode material. Those skilled in the art can detect the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD pattern of the cathode material using conventional techniques. For example, the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD pattern of the cathode material can be detected using the following method:

[0039] The battery was discharged to 2.5V at 0.33C, the positive electrode was disassembled, the positive electrode was immersed in DMC at room temperature for 60 minutes, taken out, dried, and the positive electrode material on the surface of the current collector was scraped off. The obtained positive electrode material was subjected to XRD test, and the intensity of the diffraction peaks corresponding to the (003) crystal plane and the (104) crystal plane was recorded to obtain I(003) and I(104). Then the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the positive electrode material was calculated.

[0040] The specific test conditions for XRD testing are as follows: Cu target, scanning voltage of 40KV, current of 40mA, scanning range of 5-80°, scanning speed of 2° / min, XRD is calibrated by silicon internal standard method, and the XRD instrument used can be the Ultima IV from Rigaku, Japan.

[0041] In the XRD pattern, the diffraction peak at a diffraction angle of 2θ of 18.5±0.3° is the (003) crystal plane diffraction peak, and the diffraction peak at a diffraction angle of 2θ of 44.5±0.3° is the (104) crystal plane diffraction peak.

[0042] The peak position difference of the (131) crystal plane (a), the mass content of lithium nickel cobalt manganese oxide in the cathode material (b), and the intensity ratio of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the cathode material at 80% SOC and 20% SOC all affect the high-temperature performance of the battery to varying degrees, such as high-temperature cycle performance and high-temperature storage performance. It is difficult to achieve good high-temperature performance of the battery by controlling a single variable, such as having both good high-temperature cycle performance and high-temperature storage performance. This invention achieves a balance between the polarization and capacity utilization of olivine phosphate, the lithium-ion diffusion barrier of NCM, and the thermal stability of NCM by compounding olivine phosphate with NCM and adjusting the peak position difference (a) of the (131) crystal plane in the XRD patterns of the cathode at 80% SOC and 20% SOC, the mass content of lithium nickel cobalt manganese oxide in the cathode material (b), and the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD pattern of the cathode material. This results in better high-temperature performance of the battery, such as high-temperature cycle performance and high-temperature storage performance. The above relationship involves a raised to the power of (c / 1.2), which indicates a nonlinear coupling relationship between a and c. This reflects the regulatory effect of the NCM crystal structure characteristics on the lattice parameter changes of olivine phosphate, and further illustrates the comprehensive influence of the interaction between crystal structure characteristics and lattice parameter changes on the high-temperature performance of the battery.

[0043] For example, the 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 any range formed by any two of the above values.

[0044] In one preferred embodiment, the battery satisfies: 0.008 ≤ a (c / 1.2) • b ≤ 0.036. Control a (c / 1.2) The value of b is within this specific range to better balance the polarization and capacity utilization of olivine phosphate, the lithium-ion diffusion barrier of NCM, and the thermal stability of NCM, thereby further improving the high-temperature performance of the battery, such as high-temperature cycle performance and high-temperature storage performance.

[0045] In some embodiments, the peak position difference (a) of the crystal plane in the XRD spectrum of the positive electrode at 80% SOC and 20% SOC 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 any two of the above values.

[0046] In one preferred embodiment, the peak position difference (a) of the crystal plane (131) in the XRD pattern of the positive electrode at 80% SOC and 20% SOC of the battery ranges from 0.10° to 0.15°.

[0047] When the peak position difference (a) of the crystal plane (131) in the XRD spectrum of the positive electrode at 80% SOC and 20% SOC of the battery is in the range of 0.05° to 0.20°, especially in the range of 0.10° to 0.15°, the stability of olivine phosphate is more suitable, which makes the battery perform better in high-temperature storage and cycling.

[0048] In some embodiments, the mass content (b) of lithium nickel cobalt manganese oxide in the cathode 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 any range formed by any two of the above values.

[0049] In one preferred embodiment, the mass content (b) of the lithium nickel cobalt manganese oxide in the cathode material ranges from 0.05 to 0.20.

[0050] When the mass content (b) of the lithium nickel cobalt manganese oxide in the cathode material is in the range of 0.01 to 0.50, especially in the range of 0.05 to 0.20, it is more conducive to balancing the polarization of olivine phosphate and the thermal stability of the cathode material, so that the high-temperature performance of the battery, such as high-temperature cycle performance and high-temperature storage performance, is better.

[0051] In some embodiments, the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the cathode 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 any two of the above values.

[0052] In one preferred embodiment, the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the cathode material ranges from 1.0 to 1.5.

[0053] When the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the cathode material is in the range of 0.5 to 1.8, especially in the range of 1.0 to 1.5, the disorder of NCM is more suitable, the cycle and thermal stability are better, the diffusion 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.

[0054] In some embodiments, the range of a1 is 35.0 to 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 any range formed by two of the above values. The magnitude of the a1 value reflects the Mn content in the olivine phosphate. Controlling the a1 value within the above-mentioned suitable range is not only beneficial to improving the energy density of the battery, but also makes Mn exist more stably in the lithium manganese iron structure.

[0055] In some embodiments, the range of a2 is 35.2 to 36.0, such as 35.2, 35.3, 35.4, 35.5, 35.6, 35.7, 35.8, 35.9, 36.0 or any two of the above values, so as to reduce the risk of Mn dissolution from olivine phosphate.

[0056] In some embodiments, 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. x can be selected from 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.87, or any two of the above values; y can be selected from 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.12, 0.14, 0.15, or any two of the above values; z can be selected from 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or any two of the above values. In one embodiment, the range of x / y is 4.5 to 7, such as 4.5, 5, 5.5, 6, 6.5, 7 or any two of the above values. This not only enables lithium nickel cobalt manganese oxide to maintain a good layered structure, but also reduces the degree of disorder in lithium nickel cobalt manganese oxide.

[0057] The lithium nickel cobalt manganese oxide may be free of coating material or may be coated with coating material on part or all of its surface. This invention does not limit the type of coating material in lithium nickel cobalt manganese oxide. For example, the coating material may contain at least one element selected from the following: aluminum (Al), titanium (Ti), tungsten (W), boron (B), phosphorus (P), cobalt (Co), yttrium (Y), and silicon (Si). This invention also does not limit the content of the coating material in lithium nickel cobalt manganese oxide. For example, the content of the coating material in lithium nickel cobalt manganese oxide 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 any range formed by any two of the above values.

[0058] In some embodiments, the particle size Dv50 of the lithium nickel cobalt manganese oxide is 2.5 to 4.5 μm, such as 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm or any range formed by two of the above values.

[0059] This invention does not limit the method for detecting the particle size Dv50 of lithium nickel cobalt manganese oxide. Those skilled in the art can detect the particle size Dv50 of lithium nickel cobalt manganese oxide using conventional techniques. For example, the particle size Dv50 testing method for lithium nickel cobalt manganese oxide is as follows:

[0060] After the battery is depleted, the positive electrode sheet is disassembled and dried. 0.1-0.2g of positive electrode material powder is collected with a scraper. The obtained positive electrode material powder is photographed using a scanning electron microscope (SEM). The size of lithium nickel cobalt manganese oxide in the positive electrode material powder in the SEM image is measured using MEARSURE NANO software. The size of lithium nickel cobalt manganese oxide particles is collected using the diagonal line method. After the sample size reaches more than 100, the particle size distribution is statistically analyzed, and the particle size-related parameter of lithium nickel cobalt manganese oxide, Dv50, is calculated.

[0061] In this invention, the preparation method of the lithium nickel cobalt manganese oxide is not limited, and those skilled in the art can prepare the lithium nickel cobalt manganese oxide using conventional techniques. Exemplarily, the preparation method of the lithium nickel cobalt manganese oxide includes the following steps:

[0062] Lithium nickel cobalt manganese oxide precursor and lithium source are mixed and sintered to obtain lithium nickel cobalt manganese oxide.

[0063] The lithium nickel cobalt manganese oxide precursor contains Ni, Co, and Mn in a target stoichiometric ratio (i.e., the ratio of these three elements in the lithium nickel cobalt manganese oxide precursor is the same as the ratio of these three elements in the obtained lithium nickel cobalt manganese oxide, and other similar expressions are similar). The lithium nickel cobalt manganese oxide precursor is one or more of the oxides, hydroxides, and carbonates of Ni, Co, and Mn. For example, the lithium nickel cobalt manganese oxide precursor is a hydroxide of Ni, Co, and Mn.

[0064] The lithium nickel cobalt manganese oxide precursor can be obtained by methods known in the art, such as co-precipitation, gelation, or solid-state methods. As an example, the preparation method of the lithium nickel cobalt manganese oxide precursor includes the following steps:

[0065] Ni source, Co source and Mn source are dispersed in solvent to obtain a mixed solution;

[0066] The resulting mixed solution, strong alkali solution, and complexing agent solution are simultaneously pumped into a stirred reactor. The pH of the reaction solution is controlled at 10–13, and the temperature inside the reactor is controlled at 25°C–90°C. During the reaction, an inert atmosphere (such as nitrogen or at least one of inert gases) is introduced for protection. After the reaction is completed, the mixture is aged, filtered, washed, and vacuum dried to obtain a hydroxide containing Ni, Co, and Mn, which is the lithium nickel cobalt manganese oxide precursor.

[0067] In the process of preparing the lithium nickel cobalt manganese oxide 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;

[0068] 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;

[0069] 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;

[0070] And / or, the base used in the strong base solution includes, but is not limited to, at least one of sodium hydroxide and potassium hydroxide;

[0071] And / or, the complexing agent solution used includes, but is not limited to, ammonia.

[0072] In the process of preparing the lithium nickel cobalt manganese oxide precursor, the amounts of Ni source, Co source and Mn source used can be selected to satisfy the following molar amounts: Ni molar amounts: Co molar amounts: Mn molar amounts = (0.55~0.95):(0.03~0.15):(0.1~0.4).

[0073] In the process of preparing the lithium nickel cobalt manganese oxide, the Li source used 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), and lithium nitrate (LiNO3).

[0074] In the process of preparing the lithium nickel cobalt manganese oxide, the ratio of the amount of lithium source and the amount of ternary material precursor used satisfies the following: molar amount of Li element: sum of molar amounts of Ni, Co and Mn elements = (1~1.05):1.

[0075] When mixing lithium nickel cobalt manganese oxide precursor and lithium source, a ball mill or high-speed mixer can be used.

[0076] In the process of preparing lithium nickel cobalt manganese oxide using lithium nickel cobalt manganese oxide precursor, the sintering atmosphere is an inert atmosphere, such as a nitrogen atmosphere, a helium atmosphere, or an argon atmosphere.

[0077] In the process of preparing lithium nickel cobalt manganese oxide using lithium nickel cobalt manganese oxide precursor, the sintering temperature can be selected as 700-1000℃ and the sintering time can be selected as 6-9h.

[0078] In addition, when preparing lithium nickel cobalt manganese oxide precursor, a certain amount of dopant element source (if any) can be dispersed together with Ni source, Co source and Mn source in solvent to prepare lithium nickel cobalt manganese oxide precursor. The dopant element source is selected from at least one of Al source, W source, Mg source, Sr source, Zr source, etc., to obtain lithium nickel cobalt manganese oxide containing a certain amount of dopant element.

[0079] In the preparation of lithium nickel cobalt manganese oxide, the lithium nickel cobalt manganese oxide can also be coated as needed. Specifically, a dry coating method (high-temperature solid-state method) is used to coat the surface of the lithium nickel cobalt manganese oxide with a coating material, and the surface of the lithium nickel cobalt manganese oxide is partially or completely coated with a coating layer formed by the coating material. For example, the coating layer contains at least one element selected from the following (hereinafter referred to as the "coating element"): aluminum (Al), phosphorus (P), silicon (Si), titanium (Ti), tungsten (W), boron (B), cobalt (Co), or yttrium (Y).

[0080] In some embodiments, the olivine-type phosphate includes at least one of lithium manganese iron phosphate and doped lithium manganese iron phosphate.

[0081] In some embodiments, the manganese element in the olivine-type phosphate accounts for 60% to 85% of the total transition metal element molar content, such as 60%, 65%, 70%, 75%, 80%, 85%, or any range formed by two of the above values.

[0082] In some of the 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 a range formed by any two of the above values.

[0083] It should be noted that the average primary particle size of the olivine-type phosphate in the positive electrode active material described in the present application can be determined by the following method: disassemble the battery to obtain the positive electrode plate, soak it in dimethyl carbonate (DMC), dry it, scrape out the positive electrode material from the positive electrode plate for EDS energy spectrum test, identify olivine-type phosphate and layered lithium nickel cobalt manganate particles by point scanning identification under an enlarged view, select three regions of the olivine-type phosphate under a scanning electron microscope at 30k magnification to obtain particle morphology, measure the diagonal length of primary particles of the olivine-type phosphate by nanomeasurer software, test 80 particles as samples, and count the results of the three regions, which is the average primary particle size of the olivine-type phosphate.

[0084] In some embodiments, the chemical formula of lithium manganese iron phosphate is LiMn d Fe 1-d PO4, wherein 0 < d < 1. d can be selected from 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, 0.99, or a range formed by any two of the above values. The lithium manganese iron phosphate may or may not contain doping elements. The present invention does not limit the types of doping elements in lithium manganese iron phosphate, for example, the doping elements include but are not limited to at least one of V, W, Ti, and Mg; meanwhile, the present invention does not limit the content of doping elements in lithium manganese iron phosphate. For example, the content of doping elements in lithium manganese iron phosphate is 500 to 2000 ppm. The lithium manganese iron phosphate may have no coating material, or may have a coating material coated on part or all of its surface. The present invention does not limit the types of coating materials for lithium manganese iron phosphate, for example, the coating material includes at least one of graphene and carbon nanotubes; meanwhile, the present invention does not limit the content of the coating material in lithium manganese iron phosphate. For example, the content of the coating material in lithium manganese iron phosphate is 1.5 to 2.5 wt%, such as 1.5 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.5 wt%, or a range formed by any two of the above values.

[0085] In the present invention, there is no limitation on the preparation method of the olivine-type phosphate, and those skilled in the art can prepare the olivine-type phosphate according to conventional technical means. Illustratively, the preparation method of the olivine-type phosphate comprises the following steps:

[0086] Manganese source, iron source, phosphorus source, lithium source and solvent are mixed and reacted at 140-160℃ for 8-12 hours to obtain olivine-type phosphate precursor;

[0087] The obtained olivine-type phosphate precursor and carbon source are dispersed in a solvent. The resulting mixture is spray-dried and then calcined under a protective atmosphere to obtain olivine-type phosphate.

[0088] For example, in the preparation of the olivine-type phosphate, the manganese source used includes, but is not limited to, at least one of manganese tetroxide, manganese nitrate, manganese carbonate, manganese oxalate, manganese sulfate, manganese chloride, and manganese acetate.

[0089] For example, the iron source used includes, but is not limited to, at least one of ferrous sulfate, ferric phosphate, ferrous phosphate, ferric hydroxide, ferrous hydroxide, ferrous carbonate, ferrous carbonate, ferric acetate, ferrous acetate, ferric oxide, ferric oxide, ferrous oxalate, and ferric oxalate.

[0090] 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.

[0091] 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.

[0092] For example, the solvents used include, but are not limited to, water.

[0093] 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 preparation of the lithium manganese iron phosphate precursor, the molar ratio of manganese source, iron source, and phosphorus source used is (0.6-0.85):(0.15-0.4):(1.02-1.05).

[0094] For example, the protective atmosphere is an inert atmosphere, such as a nitrogen atmosphere.

[0095] For example, the calcination temperature can be selected as 550 to 680°C, such as 550°C, 600°C, 650°C, 680°C or any range formed by two of the above values.

[0096] For example, the calcination time is 4 to 10 hours, such as 6 hours or any range formed by two of the above values.

[0097] In the preparation of the olivine-type phosphate, dopant elements can also be used. For example, when the olivine-type phosphate precursor and a carbon source are dispersed in a solvent, dopant elements can be added and dispersed together, followed by spray drying and calcination under a protective atmosphere to obtain the olivine-type phosphate. Exemplarily, the dopant elements include, but are not limited to, at least one of V, W, Ti, and Mg sources.

[0098] In some embodiments, the mass content of the olivine-type phosphate in the cathode material ranges from 0.46 to 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 any range formed by two of the above values.

[0099] In some embodiments, the mass content of the positive electrode active material in the positive electrode material is 0.95 to 0.985, such as 0.950, 0.965, 0.970, 0.980, 0.985 or any range formed by two of the above values.

[0100] In addition to the aforementioned positive electrode active material, the positive electrode material also includes a positive electrode conductive agent and a positive electrode binder.

[0101] The positive electrode conductive agent is used to provide conductivity. 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. Examples of positive electrode conductive agents include, but are not limited to, at least one of carbon nanotubes, carbon black, graphite, carbon fibers, activated carbon, mesoporous carbon, and fullerenes, wherein carbon fibers include, for example, carbon nanofibers; and carbon black includes, for example, SP (Super P), acetylene black, and Ketjen black.

[0102] In some embodiments, the mass content of the positive electrode conductive agent in the positive electrode material is 0.01 to 0.04, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040 or any range formed by two of the above values.

[0103] Positive electrode binders are 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. Any binder can be used without particular limitation, as long as it has suitable adhesive properties and does not significantly cause adverse chemical changes in the battery. Examples of positive electrode binders include, but are not limited to, fluorinated polyolefin binders, including but not limited to polyvinylidene fluoride (PVDF), PVDF copolymers, or their modified derivatives (e.g., modified with carboxylic acids, acrylic acid, acrylonitrile, etc.).

[0104] In some of these embodiments, the mass content of the positive electrode binder in the positive electrode material is 0.01 to 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.

[0105] The positive electrode material may be disposed on one surface of the positive electrode current collector, or may be disposed on both surfaces of the positive electrode current collector.

[0106] There is no particular limitation on the positive electrode current collector in the present invention, as long as it has electrical conductivity and does not cause adverse chemical changes in the battery. For example, aluminum, nickel, titanium, stainless steel, sintered carbon; or aluminum or stainless steel surface-treated with one of carbon, nickel, titanium, silver, etc. can be used.

[0107] The positive electrode sheet of the present invention can be prepared by a conventional method in the art. For example, the positive electrode active material, the positive electrode conductive agent and the positive electrode binder are dispersed in a solvent to obtain a positive electrode slurry, and then the positive electrode slurry is coated on at least one surface of the positive electrode current collector, and the positive electrode sheet is obtained after processes such as drying, rolling, and slitting. Wherein, the solvent used for preparing the positive electrode slurry includes, but is not limited to, at least one of N-methylpyrrolidone (NMP) and deionized water.

[0108] Battery

[0109] The present invention also provides a battery comprising the positive electrode sheet, a negative electrode sheet and an electrolyte.

[0110] The negative electrode sheet of the present invention comprises a negative electrode current collector and a positive electrode material located on at least one surface of the negative electrode current collector, and the negative electrode material comprises a negative electrode active material.

[0111] There is no particular limitation on the negative electrode active material in the present invention. Exemplarily, the negative electrode active material includes, but is not limited to, natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon, SiO f (0<f<2, for example f=1), silicon-carbon, Li4Ti5O 12 at least one of.

[0112] In some of these embodiments, the negative electrode active material comprises graphite, and the average particle diameter of graphite is 8 to 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.

[0113] The present invention does not limit the detection method for the average particle diameter of graphite, and those skilled in the art can detect the average particle diameter of graphite according to conventional technical means. Exemplarily, the test method for the average particle diameter of graphite is as follows:

[0114] Disassemble the secondary battery in its empty state, scrape off the powder from the negative electrode, and test it according to the D50 test method in the national standard GB / T24533-2019.

[0115] In some embodiments, the mass content of the negative electrode active material in the negative electrode material is 0.93 to 0.98, such as 0.93, 0.95, 0.97, 0.98 or any range formed by two of the above values.

[0116] The negative electrode active material layer may also contain a negative electrode conductive agent and / or a negative electrode binder.

[0117] 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. For example, 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, and fullerenes, wherein carbon fibers are, for example, carbon nanofibers; and carbon black is, for example, SP, acetylene black, Ketjen black, etc.

[0118] In some embodiments, the mass content of the negative electrode conductive agent in the negative electrode material is 0.01 to 0.05, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, or any range formed by two of the above values.

[0119] Negative electrode binders are used to improve the adhesion between negative electrode active material particles and the adhesion between the negative electrode active material and the negative electrode current collector. Any binder can be used without particular limitation, as long as it has suitable adhesive properties and does not significantly cause adverse chemical changes in the battery. Examples of negative electrode binders include, but are not limited to, fluorinated polyolefin binders, including but not limited to polyvinylidene fluoride (PVDF), PVDF copolymers, or their modified derivatives (e.g., modified with carboxylic acids, acrylic acid, acrylonitrile, etc.).

[0120] In some embodiments, the mass content of the negative electrode binder in the negative electrode material is 0.01 to 0.05, such as 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, or any range formed by two of the above values.

[0121] 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.

[0122] The present invention does not impose any particular restrictions on the negative electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface-treated with at least one of carbon, nickel, titanium, silver, etc., or aluminum-cadmium alloy.

[0123] The electrolyte of this invention can be any of the various electrolytes suitable for batteries in the art. The electrolyte comprises an electrolyte and a solvent, and the electrolyte typically includes a lithium salt.

[0124] For example, the lithium salt includes, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate 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 as 0.9–2.0 mol / L.

[0125] For example, the solvent includes, but is not limited to, at least one selected from 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), butyl 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 can be selected from 0.55 to 0.92%.

[0126] In addition, the electrolyte may also contain additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery high-temperature performance, battery overcharge performance, and battery low-temperature performance.

[0127] The battery may further include a separator located between the positive and negative electrode plates to separate them and prevent short circuits. The separator can be any suitable battery separator material in the art. Exemplarily, the separator includes, but is not limited to, at least one of polypropylene and polyethylene.

[0128] Electrical appliances

[0129] The present invention also provides an electrical device comprising the battery. The battery serves as the power supply for the electrical device.

[0130] The term "electrical device" refers to any device that can utilize electrical energy and convert it into mechanical energy, thermal energy, light energy, or one or more other energy forms, such as electric motors, electric heaters, and electric light sources. Specifically, it can include, but is not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, and energy storage systems. Mobile devices can include mobile phones, laptops, drones, robot vacuum cleaners, and e-cigarettes; electric vehicles can include pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, and electric trucks.

[0131] The present invention is further illustrated below with specific embodiments. It should be noted that, unless otherwise specified, the sintering is carried out in an air atmosphere:

[0132] Example 1

[0133] This embodiment provides a lithium-ion battery, and the specific preparation method is as follows:

[0134] (1) Preparation of positive electrode

[0135] Preparation of olivine-type lithium manganese iron phosphate: MnSO4, FeSO4, and H3PO4 were mixed uniformly in a molar ratio of 6:4:10. After adding water, a mixed solution with a transition metal element concentration of 1M was prepared. Then, ascorbic acid and LiOH were added, wherein the amount of ascorbic acid added was 0.2% of the total molar amount of MnSO4, FeSO4, and H3PO4, and the amount of LiOH added was 3 times the molar amount of H3PO4. The resulting mixture was stirred at 70℃ for 6 hours, then pressurized and heated to 150℃ for 10 hours. The solid was separated, dried, and then the resulting powder was dispersed in water. A carbon source of 21 wt% of the powder mass was added, spray-dried, and finally calcined at 800℃ under a nitrogen atmosphere to obtain carbon-coated lithium manganese iron phosphate.

[0136] The values ​​of t and the selection of carbon source are shown in Table 1.

[0137] Preparation of lithium nickel cobalt manganese oxide: Nickel acetate, cobalt acetate, manganese acetate and sodium hydroxide were mixed and dissolved in water at a molar ratio of 6:1:3:10. The mixture was reacted at 80°C for 24 hours. The solid was separated. The precursor with an average particle size of 3.5 μm was mixed with lithium hydroxide at a stoichiometric ratio and then calcined at n°C for 8 hours in an air atmosphere to obtain lithium nickel cobalt manganese oxide.

[0138] The possible values ​​of n are shown in Table 1.

[0139] Preparation of positive electrode sheet: The obtained olivine phosphate and NCM are mixed according to the ratio in Table 1 to form the positive electrode active material. The positive electrode active material is mixed with binder PVDF and conductive agent SP at a mass ratio of 97:2:1 and dispersed in NMP to obtain positive electrode slurry. The positive electrode slurry is coated on both sides of aluminum foil and then rolled and cut to obtain positive electrode sheet.

[0140] (2) Preparation of negative electrode sheet

[0141] Artificial graphite with a particle size of 12μm, conductive agent SP, and binder CMC are mixed at a mass ratio of 96.4:1:2.6 and dispersed in deionized water to obtain a negative electrode slurry. The negative electrode slurry is coated on both sides of a copper foil, and after drying, rolling and cutting, a negative electrode sheet is obtained.

[0142] (3) Preparation of electrolyte

[0143] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain a mixed organic solvent. Then, dried lithium salt LiPF6 was dissolved in the above mixed organic solvent to prepare an electrolyte with a LiPF6 concentration of 1 mol / L.

[0144] (4) Preparation of the separating membrane

[0145] A polyethylene (PE) diaphragm is used.

[0146] (5) Assembly and formation

[0147] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. The cells are then wound to obtain a bare cell. The bare cell is placed in an outer packaging shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a lithium-ion battery is obtained.

[0148] Examples 2-27 and Comparative Examples 1-2

[0149] These examples and comparative examples all provide a lithium-ion battery, and the preparation method is similar to that of Example 1, except that:

[0150] When preparing olivine-type lithium manganese iron phosphate, the molar ratio of MnSO4, FeSO4 and H3PO4 is adjusted according to the chemical structure of lithium manganese iron phosphate. The chemical structure of lithium manganese iron phosphate, the value of t and the selection of carbon source are shown in Table 1.

[0151] When preparing lithium nickel cobalt manganese oxide containing lithium 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. The molar ratio of nickel acetate, cobalt acetate and manganese acetate is adjusted according to the chemical structural formula of lithium nickel cobalt manganese oxide. The chemical structural formula of lithium nickel cobalt manganese oxide and the value of n are shown in Table 1.

[0152] The mass ratio of the positive electrode active material (i.e., the main positive electrode material) to the binder and conductive agent during the preparation of the positive electrode sheet is shown in Table 1.

[0153] Table 1

[0154]

[0155]

[0156]

[0157] The above method was used to detect the peak position difference (a) of the (131) crystal plane, the mass content (b) of lithium nickel cobalt manganese oxide in the cathode material, and the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD spectrum of the cathode material in each embodiment and comparative example under 80% SOC and 20% SOC conditions. The test results are shown in Table 2.

[0158] Performance tests were conducted on the lithium-ion batteries of each embodiment and comparative example. The test results are shown in Table 2. The specific test methods are as follows:

[0159] High-temperature cycle performance test: After the lithium-ion battery was left to stand at 45℃ for 120 minutes, it was charged and discharged according to the following procedure: 1C constant current and constant voltage full charge, cut-off voltage 4.25V, cut-off current 0.33C, left to stand for 20 minutes, and then 1C constant current discharge to 2.5V; the above charge and discharge is one cycle, and the cycle charge and discharge is performed. The discharge capacity of the first 1C cycle is taken as the initial first cycle discharge capacity. The ratio of the discharge capacity after 100 cycles of 1C charge and discharge to the initial first cycle discharge capacity is taken as the capacity retention rate of the battery after 100 cycles at high temperature.

[0160] High-temperature storage performance test: At 25℃, the battery is fully charged at 0.33C constant current and constant voltage, with a cutoff voltage of 4.25V and a cutoff current of 0.33C. After resting for 20 minutes, it is discharged at 0.33C constant current to 2.5V. This constitutes one cycle, and two cycles are performed. The capacity e from the second cycle is recorded. After being transferred to a 60℃ incubator for 7 days, the battery is transferred to a 25℃ incubator and rested for 4 hours. It is then discharged at 25℃ at 0.33C constant current to 2.5V, and the capacity f is recorded. This is followed by a full charge at 0.33C constant current and constant voltage, with a cutoff voltage of 4.25V and a cutoff current of 0.33C. After resting for 20 minutes, it is discharged at 0.33C constant current to 2.5V, and the capacity g is recorded. f / e is the capacity retention rate after storage, and g / e is the capacity recovery rate after storage.

[0161] Table 2

[0162]

[0163] For the batteries prepared in the various embodiments of the present invention, the capacity retention rate after 100 cycles at 45°C and 1C is ≥90%, the capacity retention rate after 7 days of storage at 60°C is ≥83%, and the capacity recovery rate after 7 days of storage at 60°C is ≥80%. It can be seen that the batteries containing the positive electrode sheet of the present invention have excellent high-temperature cycling and storage performance.

[0164] Comparing Examples 1-7 with Examples 8-13, and Examples 14-15 with Examples 16-21, it can be seen that when the peak position difference (a) of the (131) crystal plane in the XRD spectrum of the positive electrode sheet at 80% SOC and 20% SOC, 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 to the (104) diffraction peak in the XRD spectrum of the positive electrode material meet the preferred range described in this invention, the high-temperature cycling and storage performance of the battery is relatively better.

[0165] Comparing Examples 1-7 with Examples 14-15, and Examples 8-13 with Examples 16-21, it can be seen that when the battery satisfies 0.008 ≤ a (c / 1.2) When b≤0.036, the battery exhibits relatively better high-temperature cycling and storage performance.

[0166] According to Comparative Examples 1 and 2, even when the peak position difference (a) of the (131) crystal plane, the mass content of lithium nickel cobalt manganese oxide in the cathode material, and the intensity ratio (c) of the (003) diffraction peak to the (104) diffraction peak in the XRD pattern of the cathode material are within a suitable range at 80% SOC and 20% SOC, when a (c / 1.2) When the value of b exceeds the range of 0.004 to 0.190, the battery's high-temperature cycling and storage performance are relatively poor.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this article and are not intended to limit the scope of protection of this article. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this article without departing from the essence and scope of the technical solutions of this article.

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; The range of 'a' is 0.05° to 0.20°. 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.

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 0.10° to 0.15°.

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

50.

5. The battery as described in claim 4, characterized in that, The range of b is 0.05 to 0.

20.

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

8.

7. The battery as described in claim 6, characterized in that, The range of c is 1.0 to 1.

5.

8. The battery as claimed in claim 1, characterized in that, The range of a1 is 35.0 to 35.9, and the range of a2 is 35.2 to 36.

0.

9. The battery as claimed in claim 1, characterized in that, At least one of the following conditions must be met: S1. The olivine-type phosphate includes at least one of lithium manganese iron phosphate and doped lithium manganese iron phosphate; S2. The manganese element accounts for 60% to 85% of the total transition metal elements in the olivine-type phosphate; S3. The average primary particle size range of the olivine-type phosphate is 80–200 nm; S4. The particle size Dv50 of the lithium nickel cobalt manganese oxide ranges from 2.5 to 4.5 μm; S5. The mass content of the olivine-type phosphate in the cathode material ranges from 0.46 to 0.

95. S6. 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 appliance, characterized in that, It includes the battery as described in any one of claims 1 to 9.

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