Positive electrode sheet and battery

Abstract

The present disclosure relates to the field of batteries, and in particular to a positive electrode sheet and a battery. The positive electrode sheet comprises a first positive electrode active material containing single crystal particles and a second positive electrode active material containing polycrystalline particles; the first positive electrode active material comprises elements A1 and A'1, the second positive electrode active material comprises elements A2 and A'2, and the content m2 of the element A'1 is less than or equal to the content m4 of the element A'2. The positive electrode sheet of the present disclosure has high compacted density and good electrochemical performance. The battery of the present disclosure has high energy density, good cycle performance and low internal resistance.

Description

Positive electrode and battery Technical Field

[0001] The present disclosure relates to the field of batteries, and in particular to a positive electrode sheet and a battery comprising the positive electrode sheet. Background Art

[0002] With the rapid growth in sales of new energy vehicles, the industry's demand for battery life is also increasing. Ternary lithium-ion batteries with large-scale mass production capabilities have attracted much attention. However, the energy density of single cells that can be mass-produced in ternary lithium-ion batteries is generally less than 300Wh / kg. Therefore, more and more research is devoted to improving the energy density of ternary lithium-ion batteries. One of the more mainstream methods is to increase the upper limit voltage of ternary lithium-ion batteries to increase the gram capacity and achieve the purpose of increasing the energy density of lithium-ion batteries. However, the cycle performance of ternary lithium-ion batteries will rapidly decline under high voltage. Summary of the Invention

[0003] The present disclosure aims to overcome the aforementioned problems existing in the prior art by providing a positive electrode sheet and a battery including the same. The positive electrode sheet disclosed herein has a high compaction density and excellent electrochemical performance. Batteries including the positive electrode sheet disclosed herein have excellent energy density and cycle performance, as well as low internal resistance.

[0004] The first aspect of the present disclosure provides a positive electrode sheet, the positive electrode sheet comprising a positive electrode active material, the positive electrode active material comprising a first positive electrode active material and a second positive electrode active material; the first positive electrode active material comprises single crystal particles, the second positive electrode active material comprises polycrystalline particles; the first positive electrode active material comprises element A 1 and A' 1 The second positive electrode active material includes element A 2 and A' 2 , element A 1 and element A 2 Each independently includes at least one of Sr, Y, Mg, Mo, Zr and Ti; element A' 1 and element A' 2 Each independently includes at least one of W, Al and B; element A' 1 The content of the first positive electrode active material is m2, element A' 2 The content of the second positive electrode active material is m4, satisfying m2≤m4.

[0005] A second aspect of the present disclosure provides a battery, comprising the positive electrode sheet described in the first aspect of the present disclosure.

[0006] Through the above technical solution, the present disclosure has at least the following advantages compared with the prior art:

[0007] (1) The positive electrode sheet disclosed herein has a positive electrode active material with a specific composition and a high compaction density (e.g., greater than 3.3 mg / cm 3 ), with excellent electrochemical performance;

[0008] (2) The battery disclosed herein includes the above-mentioned positive electrode sheet, which can reduce the cracking of the positive electrode active material particles under high voltage conditions (e.g., 4.25V), thereby reducing the occurrence of side reactions between the positive electrode active material and the electrolyte, and improving the energy density and cycle life of the battery.

[0009] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a scanning electron microscope (SEM) image of a positive electrode sheet in an example of the present disclosure.

[0011] FIG2 is a cross-sectional SEM image of a positive electrode sheet in an example of the present disclosure.

[0012] FIG3 shows a cross-sectional SEM image of a positive electrode sheet in an example of the present disclosure.

[0013] FIG4 shows a volume particle size test curve of a positive electrode sheet in an example of the present disclosure.

[0014] FIG5 shows an XRD diffraction pattern of the positive electrode sheet in an example of the present disclosure.

[0015] FIG6 shows a DSC spectrum of a positive electrode sheet in an example of the present disclosure. DETAILED DESCRIPTION

[0016] A first aspect of the present disclosure provides a positive electrode sheet, which may include a positive electrode active material. The positive electrode active material may include a first positive electrode active material and a second positive electrode active material. The first positive electrode active material may include single crystal particles, and the second positive electrode active material may include polycrystalline particles.

[0017] Current ternary cathode materials can be divided into single crystal and polycrystalline based on their microscopic morphology. Due to the different crystal structures of single crystals and polycrystalline, single crystals have better high voltage carrying capacity than polycrystalline, and have higher energy density and cycle stability. Since the interior of the single crystal has a consistent arrangement orientation and fewer grain boundaries, the structural stability is strong, and there are fewer side reactions with the electrolyte, making the single crystal less likely to break during the battery cycle and having excellent cycle stability; single crystals can withstand higher voltages, allowing more lithium ions to be intercalated and deintercalated, thereby increasing the energy density of the battery. In addition, the single crystal has high mechanical strength, which makes the positive electrode sheet have a higher compaction density. Under the same volume, more active materials can be loaded, thereby further improving the energy density. However, there are a large number of grain boundaries inside the polycrystalline. During the battery cycle, grain boundary cracking and particle crushing are prone to occur, which causes the crystal to decompose and have side reactions with the electrolyte, resulting in reduced battery cycle performance and a significant increase in impedance.

[0018] Although single crystal ternary materials can be used at high voltage, giving them higher energy density and cycle stability, using them alone as positive electrode active materials will increase battery polarization and internal resistance, thereby affecting electrical performance. The reason may be that the primary particle size of single crystal ternary materials is larger than that of polycrystalline ternary materials, which increases the Li + The inventors of this disclosure have found that using both single crystal and polycrystalline as positive electrode active materials can significantly reduce the internal resistance of the battery while ensuring high energy density and cycle stability. This may be due to the smaller particle size of the primary particles in the polycrystalline material, Li + The diffusion speed is faster, which makes the battery have better fast charging performance and a lower DCIR (Direct Current Internal Resistance) growth rate during fast charging.

[0019] Figure 1 shows a scanning electron microscope (SEM) image of a positive electrode sheet in one embodiment of the present disclosure. As can be seen from the image, the positive electrode active material includes single-crystal particles and polycrystalline particles. The particles enclosed by a solid black circle are single-crystal particles, while the particles enclosed by a dashed black circle are polycrystalline particles.

[0020] In one example, the first positive electrode active material is a single crystal particle, and the second positive electrode active material is a polycrystalline particle.

[0021] In this disclosure, the terms "single crystal" and "polycrystalline" have the conventional meanings in the art. It is generally believed that the term "single crystal" refers to primary particles, which are directly composed of independent crystals (e.g., particle size of 0.2 μm-5 μm). The term "polycrystalline" refers to secondary particles, which are generally formed by the agglomeration of primary particles.

[0022] In the present disclosure, the first positive active material may include element A 1 and A' 1 , the second positive active material may include element A 2 and A' 2 , element A 1 and element A 2 Each independently includes at least one of Sr, Y, Mg, Mo, Zr and Ti; element A' 1 and element A' 2 Each independently includes at least one of W, Al and B; element A' 1 The content of the first positive electrode active material is m2, element A' 2 The content of the second positive electrode active material is m4, satisfying m2≤m4 (i.e., m4 / m2≥1, for example, m4 / m2 is equal to 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100).

[0023] In related technologies, the cycling performance of ternary lithium-ion batteries rapidly degrades under high voltages. The inventors of the present disclosure have discovered that the inclusion of specific elements in both the first and second positive electrode active materials can further improve the battery's energy density and reduce its internal resistance. Furthermore, specific elements can affect the structural stability of single-crystal particles. When the specific element content in the first positive electrode active material is less than or equal to the specific element content in the second positive electrode active material, the adverse effects of single-crystal particles on the battery's internal resistance can be reduced, improving the battery's cycling performance while maintaining high energy density and low internal resistance.

[0024] In the present disclosure, the positive electrode active material of the ternary lithium-ion battery, ie, the battery, includes the elements Li, Ni, Co, and Mn.

[0025] In one example, the positive electrode active material further includes elements Li, Ni, Co, and Mn.

[0026] In the present disclosure, element A 1The content of element A in the first positive electrode active material is m1, m1 and m2 satisfy 200ppm≤m1+m2≤10000ppm (for example, m1+m2 is equal to 200ppm, 500ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm or 10000ppm), 2 The contents m3, m3 and m4 in the second positive electrode active material satisfy 200ppm≤m3+m4≤10000ppm (for example, m3+m4 is equal to 200ppm, 500ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm or 10000ppm).

[0027] In the present disclosure, element A 1 The content m1, element A' in the first positive electrode active material 1 The content m2 of the first positive electrode active material, element A 2 The content m3 and element A' in the second positive active material 2 The content m4 in the second positive electrode active material can be obtained by conventional methods in the field, such as taking a positive electrode sheet and performing an energy dispersive spectrometer (EDS) scanning test on the positive electrode sheet (scanning voltage is 0eV-20keV); for example, performing an inductively coupled plasma (ICP) test on the positive electrode active material.

[0028] The inventors of the present disclosure have discovered that when m1+m2 and m3+m4 are within a specific range, regulating m4 / m2 can further improve the cycle stability of the battery.

[0029] In one example, 2000 ppm≤m1+m2≤10000 ppm.

[0030] In one example, 4000 ppm≤m1+m2≤7000 ppm.

[0031] In one example, 2000 ppm≤m3+m4≤10000 ppm.

[0032] In one example, 3000 ppm≤m3+m4≤6000 ppm.

[0033] In one example, 1≤m4 / m2≤6.

[0034] In one example, 1≤m4 / m2≤2.

[0035] In the present disclosure, m2 may be 1000 ppm to 3000 ppm, for example, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm or 3000 ppm.

[0036] In one example, m2 is 1500 ppm-2500 ppm.

[0037] In the present disclosure, m4 may be 1000 ppm-4300 ppm, for example, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm or 4300 ppm.

[0038] In one example, m4 is 2000 ppm-4000 ppm.

[0039] In one example, element A' 1 and element A' 2 All include Al, W and B.

[0040] The inventors of the present disclosure have discovered that when m2 and m4 are within a specific range, and both the first positive electrode active material and the second positive electrode active material include the elements Al, W, and B, the cycle stability of the battery can be further improved and the internal resistance can be reduced. This may be because, when m2 and m4 are within a specific range, the elements Al, W, and B can impart good structural stability to the positive electrode active material, and the elements W and B can impart good ionic conductivity to the positive electrode active material.

[0041] In one example, element A' 1 Including Al, W and B. The mass ratio of elements Al, W and B can be (0.9-5): (1-6): 1, wherein "0.9-5" is, for example, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5; "1-6" is, for example, 1, 2, 3, 4, 5 or 6.

[0042] In one example, element A' 1 Comprising Al, W and B, the mass ratio of elements Al, W and B is (1-2):(1.2-4):1.

[0043] In one example, element A' 2 Including Al, W and B. The mass ratio of the elements Al, W and B can be (1-3): (1-4): 1, wherein "1-3" is, for example, 1, 1.2, 1.4, 1.6, 2, 2.5, 2.6, 2.8 or 3; "1-4" is, for example, 1, 1.2, 1.5, 2, 2.5, 3, 3.5, 3.8 or 4.

[0044] In one example, element A' 2Comprising Al, W and B, the mass ratio of the elements Al, W and B is (1-1.5):(1-2):1.

[0045] The inventors of the present disclosure have discovered that when element A' 1 The mass ratio of elements Al, W and B, or when element A' 2 When the mass ratio of elements Al, W and B is within a specific range, the cycle stability of the battery can be further improved and the internal resistance can be reduced.

[0046] In the present disclosure, based on the total weight of the positive electrode active material, the content of the first positive electrode active material may be 10%-50% (for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%), and the content of the second positive electrode active material may be 50-90% (for example, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55% or 50%).

[0047] In one example, based on the total weight of the positive electrode active material, the content of the first positive electrode active material is 20%-30%, and the content of the second positive electrode active material is 70%-80%.

[0048] The inventors of the present disclosure discovered that when the contents of the first positive electrode active material and the second positive electrode active material in the positive electrode active material are within a specific range, the single crystal particles can be well filled in the gaps of the polycrystalline particles, which, on the one hand, supports the structure of the polycrystalline and has a higher compaction density and better cycle performance than polycrystalline ternary positive electrode sheets; on the other hand, compared with positive electrode sheets composed of pure single crystals, the positive electrode sheets disclosed in the present disclosure can take into account both excellent DCIR and low-temperature performance.

[0049] In the related art, the gram capacity is usually increased by increasing the Ni content in the ternary material. However, as the Ni content in the ternary material increases, the structure of the ternary material becomes increasingly unstable. When used at high voltage, the battery's cycle performance, rate performance, or high-temperature storage performance will also deteriorate. In particular, when the number of atoms of the element Ni in the molecular formula of the positive active material is ≥0.8, the battery's performance deterioration at high voltage will become more and more obvious. The positive electrode sheet disclosed in the present invention can effectively improve the above-mentioned problems. The positive electrode active material in the positive electrode sheet disclosed in the present invention has a high Ni content and can remain stable under high voltage conditions, so that the battery has a higher energy density and cycle life.

[0050] In the present disclosure, the first positive electrode active material may include a chemical formula of Li x1 Ni a1 Co b1 Mn c1 A 1d1 A’ 1 e1 A substance of O2, wherein 1 ≤ x1 ≤ 1.08 (such as 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07 or 1.08), 0.5 ≤ a1 < 1 (such as 0.5, 0.6, 0.7, 0.8, 0.9, 0.95 or 0.99), 0 < b1 ≤ 0.2 (such as 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.15, 0.18 or 0.2), 0 < c1 ≤ 0.2 (such as 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.15, 0.18 or 0.2), 0 < d1 ≤ 0.015 (such as 0.01, 0.011, 0.012, 0.013, 0.014 or 0.015), 0 < e1 ≤ 0.02 (such as 0.005, 0.01, 0.015 or 0.02).

[0051] In one example, 0.8 ≤ a1 < 1.

[0052] In the present disclosure, the second positive electrode active material may include a substance with the chemical formula Li x2 Ni a2 Co b2 Mn c2 A 2 d2 A’ 2 e2 A substance of O2, wherein 1 ≤ x2 ≤ 1.08 (such as 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07 or 1.08), 0.5 ≤ a2 < 1 (such as 0.5, 0.6, 0.7, 0.8, 0.9, 0.95 or 0.99), 0 < b2 ≤ 0.2 (such as 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.15, 0.18 or 0.2), 0 < c2 ≤ 0.2 (such as 0.01, 0.03, 0.05, 0.08, 0.1, 0.13, 0.15, 0.18 or 0.2), 0 < d2 ≤ 0.015 (such as 0.01, 0.011, 0.012, 0.013, 0.014 or 0.015), 0 < e2 ≤ 0.02 (such as 0.01, 0.011, 0.012, 0.013, 0.014 or 0.015).

[0053] In one example, 0.8 ≤ a2 < 1.

[0054] In the present disclosure, the particle size Dv of the first positive electrode active material 1 10, Dv 1 50 and Dv1 90 can meet: 1μm≤Dv 1 10≤3μm (for example, Dv 1 10 is 1μm, 1.5μm, 2μm, 2.5μm or 3μm), 2.5μm≤Dv 1 50≤5μm(for example Dv 1 50 is 2.5μm, 2.7μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm), 6μm≤Dv 1 90≤9μm(for example Dv 1 90 is 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm or 9μm).

[0055] In the present disclosure, the particle size Dv of the second positive electrode active material is 2 10. Dv 2 50 and Dv 2 90 can meet: 3μm≤Dv 2 10≤13μm (for example, Dv 2 10 is 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm or 13μm), 7μm≤Dv 2 50≤18μm(for example Dv 2 50 is 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm or 18μm), 10μm≤Dv 2 90≤20μm(for example Dv 2 90 is 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm or 20μm).

[0056] In one embodiment, the particle size of the second positive electrode active material satisfies: 3 μm ≤ Dv 2 10≤6μm, 7μm≤Dv 2 50≤13μm, 10μm≤Dv 2 90≤20μm.

[0057] In one embodiment, the particle size of the second positive electrode active material satisfies: 4 μm ≤ Dv 2 10≤13μm, 7μm≤Dv 2 50≤18μm, 10μm≤Dv 2 90≤20μm.

[0058] In the present disclosure, the particle size of the first positive electrode active material and the particle size of the second positive electrode active material can be obtained by testing by conventional methods in the field. For example, after discharging the battery to 0% SOC, the positive electrode sheet is disassembled and removed, and then soaked in dimethyl carbonate (DMC) solvent for 12 hours, and then rinsed with DMC to remove the lithium salt attached to the electrode sheet, and the aluminum foil is removed. The obtained positive electrode active material layer is placed in a high-temperature furnace at 450°C and calcined for 2 hours. The positive electrode active material powder is collected and measured by laser method using Mastersize 3000 (Malvern 3000).

[0059] In the present disclosure, the first positive electrode active material can be filled in the gaps between the second positive electrode active materials. Figure 2 shows a cross-sectional SEM image of a positive electrode sheet in an example of the present disclosure. As can be seen from the figure, the first positive electrode active material is filled in the gaps between the second positive electrode active materials.

[0060] In one example, Dv 1 10 <Dv 2 10.

[0061] In one example, Dv 1 50 <Dv 2 50.

[0062] In one example, Dv 1 90 <Dv 2 90.

[0063] The inventors of the present disclosure discovered that when the particle size of the first positive electrode active material and the particle size of the second positive electrode active material are within a specific range, the first positive electrode active material can be relatively evenly filled in the gaps formed by the second active material. At this time, the second positive electrode active material can be better supported, so that the positive electrode sheet has a suitable compaction density, thereby improving the energy density of the battery; and the gaps between the second positive electrode active materials are effectively filled, which can reduce the erosion of the electrolyte on the surface of the second positive electrode active material and weaken the occurrence of side reactions between the positive electrode sheet and the electrolyte, thereby improving the cycle stability of the battery.

[0064] In the present disclosure, the long axis of the first positive electrode active material may be 0.5 μm-3.5 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm or 3.5 μm. The long axis of the second positive electrode active material may be 1 μm-15 μm, for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm. As shown in Figure 3, a cross-sectional SEM image of a positive electrode sheet in an example of the present disclosure is shown. It can be seen from the figure that the long axis of the first positive electrode active material is 0.5 μm-3.5 μm, and the long axis of the second positive electrode active material is 1 μm-15 μm.

[0065] In one example, the major axis of the second positive electrode active material is 1 μm-8 μm.

[0066] In one example, the major axis of the second positive electrode active material is 8 μm-15 μm.

[0067] The inventors of the present disclosure discovered that when the long axis of the first positive electrode active material and the long axis of the second positive electrode active material are within a specific range, the first positive electrode active material can be relatively evenly filled in the gaps formed by the second active material. At this time, the second positive electrode active material can be better supported, so that the positive electrode sheet has a suitable compaction density, thereby improving the energy density of the battery; and the gaps between the second positive electrode active materials are effectively filled, which can reduce the erosion of the electrolyte on the surface of the second positive electrode active material and weaken the occurrence of side reactions between the positive electrode sheet and the electrolyte, thereby improving the cycle stability of the battery.

[0068] In the present disclosure, the long axis of the first positive electrode active material or the long axis of the second positive electrode active material refers to the maximum distance between any two points on the surface of the first positive electrode active material or the maximum distance between any two points on the surface of the second positive electrode active material. It can be measured by conventional methods in the art, such as by SEM.

[0069] In the present disclosure, the compaction density of the positive electrode sheet can be 3 mg / cm 3 -4mg / cm 3 , for example 3 mg / cm 3 , 3.1mg / cm 3 , 3.2mg / cm 3 , 3.3mg / cm 3 、3.4mg / cm 3 , 3.5mg / cm 3 、3.6mg / cm 3 、3.7mg / cm 3 、3.8mg / cm3 、3.9mg / cm 3 or 4 mg / cm 3 .

[0070] In one embodiment, the compaction density of the positive electrode sheet is 3.3 mg / cm 3 -3.6mg / cm 3 .

[0071] In the present disclosure, the positive electrode sheet is subjected to a volume particle size test, and the test curve has at least two characteristic peaks, wherein the peak value of the first characteristic peak corresponds to a particle size classification of P1, and the peak value of the second characteristic peak corresponds to a particle size classification of P2, satisfying 2μm≤P2-P1≤10μm (for example, P2-P1 is equal to 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, or 10μm). As shown in Figure 4, a volume particle size test curve of a positive electrode sheet in an example of the present disclosure is shown. It can be seen from the figure that 2μm≤P2-P1≤10μm.

[0072] The inventors of the present disclosure have discovered that when P2-P1 is within a specific range, the positive electrode sheet can have a good lithium ion diffusion path and tortuosity, which is beneficial to the infiltration of the electrolyte. At the same time, it can improve the filling rate of the active material, increase the compaction density and mass energy density (ED), and is beneficial to the improvement of the overall structural stability and ductility of the negative electrode sheet, thereby improving the rate performance of the positive electrode sheet.

[0073] In the present disclosure, 1 μm ≤ P1 ≤ 7 μm (e.g., 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, or 7 μm). 5 μm ≤ P2 ≤ 15 μm (e.g., 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm).

[0074] In the present disclosure, the volume particle size of the positive electrode sheet can be tested by conventional methods in the field. For example, after discharging the battery to 0% SOC, the positive electrode sheet is disassembled and taken out, and then soaked in dimethyl carbonate (DMC) solvent for 12 hours, and then rinsed with DMC to remove the lithium salt attached to the electrode sheet, and the aluminum foil is removed. The obtained positive electrode active material layer is placed in a high-temperature furnace at 450°C and calcined for 2 hours to obtain a positive electrode active material powder, and the particle size test is performed using Mastersize 3000 (Malvern 3000).

[0075] In the present disclosure, the XRD (X-Ray Diffraction) diffraction pattern of the positive electrode sheet has a 003 crystal plane peak and a 104 crystal plane peak, and the angle value corresponding to the intensity position of the 003 crystal plane peak is X 003 The angle value corresponding to the peak intensity position of the 104 crystal plane is X 104The ratio of the 003 crystal plane peak intensity to the 104 crystal plane peak intensity is 1 003 / I 104 , satisfying X 003 15°-23°, X 104 43°-45°, I 003 / I 104 As shown in FIG5, the XRD diffraction pattern of the positive electrode sheet in an example of the present disclosure is shown. 003 15°-23°, X 104 43°-45°, I 003 / I 104 1-8.

[0076] In one example, X 003 It is 18°-19°.

[0077] In the present disclosure, the XRD diffraction pattern of the positive electrode sheet can be obtained by X-ray diffractometer testing.

[0078] In the present disclosure, in the DSC (Differential Scanning Calorimetry) spectrum of the positive electrode sheet, the temperature T corresponding to the peak intensity position is DSC 200℃-250℃. As shown in FIG6, the DSC spectrum of the positive electrode sheet in an example of the present disclosure is shown. It can be seen from the figure that the temperature T corresponding to the peak intensity position DSC It is 200℃-250℃.

[0079] In the present disclosure, the DSC spectrum of the positive electrode sheet can be obtained by DSC testing, and the specific testing method is as follows: charge the battery to the upper limit voltage of 4.25V; disassemble the battery, take out the positive electrode sheet, cut the positive electrode sheet and place it in a crucible, add electrolyte, and use a differential scanning calorimeter for testing.

[0080] The inventors of the present disclosure discovered that when X 003 、X 104 、T DSC and I 003 / I 104 When specific relationships are met, first, the positive electrode sheet has an excellent layered structure, which can avoid the collapse of the layered structure due to the dissolution of transition metals, thereby making the positive electrode sheet have excellent structural stability during the battery cycle; secondly, it can improve the surface structure of the positive electrode active material, avoid the occurrence of electrode differentiation in the positive electrode sheet, and facilitate better contact with the positive electrode binder, avoiding the peeling of the active material under high temperature conditions; finally, it can not only avoid the side reaction between the positive electrode active material and the electrolyte under high temperature conditions, thereby leading to gas production and other problems, but also ensure that the positive electrode sheet can withstand higher thermal runaway temperatures, so that it has excellent thermal stability.

[0081] In this disclosure, X 003 、X 104 、T DSC and I 003 / I 104 Satisfy 0.01≤(X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.15, for example, 0.01, 0.012, 0.015, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14 or 0.15.

[0082] In one example, 0.02≤(X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.1.

[0083] In one example, 0.02≤(X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.06.

[0084] In the present disclosure, the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer includes the positive electrode active material. The positive electrode active material layer may further include a positive electrode conductive agent and a positive electrode binder. The positive electrode conductive agent may include, for example, at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, carbon nanotubes, metal powder, and carbon fiber. The positive electrode binder may include, for example, at least one of polymethyl acrylate, sodium carboxymethyl cellulose, styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene oxide.

[0085] In one example, the positive electrode sheet includes a positive electrode current collector and positive electrode active material layers on both sides of the positive electrode current collector.

[0086] The positive electrode sheet disclosed herein has high compaction density and excellent electrochemical performance.

[0087] A second aspect of the present disclosure provides a battery, comprising the positive electrode sheet described in the first aspect of the present disclosure.

[0088] In the present disclosure, the battery may further include a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector.

[0089] In one example, the negative electrode sheet includes a negative electrode current collector and negative electrode active material layers located on both sides of the negative electrode current collector.

[0090] Related technologies usually increase the gram capacity of the negative electrode by adding silicon-based materials to the negative electrode sheet of the battery in order to achieve the purpose of increasing the energy density of the battery. When the structure of the positive electrode active material is unstable, a large number of side reactions will occur under high voltage conditions. These side reactions will occur in the entire battery system, such as the positive electrode sheet, the negative electrode sheet and the separator, thereby accelerating the deterioration of the battery performance. In particular, when the negative electrode sheet includes silicon-based materials, this deterioration will be more obvious. This is mainly because the negative electrode sheet including silicon-based materials has poorer kinetics than the negative electrode sheet including only carbon-based materials, and the deterioration effect will be more significant. The battery disclosed in the present invention can effectively improve the above problems and has an excellent cycle life while having a higher energy density.

[0091] In the present disclosure, the negative electrode active material layer may include a negative electrode active material. The negative electrode active material may include at least one of a carbon-based material and a silicon-based material. The carbon-based material may include at least one of natural graphite, artificial graphite, mesocarbon microbeaded graphite, soft carbon, and hard carbon. The silicon-based material may include at least one of silicon, silicon oxide, silicon carbon, and a silicon alloy. The silicon oxide, for example, includes silicon oxide. The silicon carbon, for example, includes a composite material of carbon and silicon.

[0092] In one example, the negative electrode active material includes a carbon-based material and a silicon-based material.

[0093] In one example, the carbon-based material includes at least one of artificial graphite and natural graphite.

[0094] In one example, the carbon-based material includes artificial graphite.

[0095] In the present disclosure, the median particle size Dv50 of the carbon-based material may be 9 μm to 18 μm, for example, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm or 18 μm. The specific surface area of ​​the carbon-based material may be 0.9 m 2 / g-3m 2 / g, for example 0.9m 2 / g、1m 2 / g, 1.1m 2 / g, 1.2m 2 / g, 1.3m 2 / g, 1.4m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.7m 2 / g, 1.8 m 2 / g, 1.9 m 2 / g, 2 m 2 / g, 2.1 m 2 / g, 2.2 m 2 / g, 2.3 m 2 / g, 2.4 m 2 / g, 2.5 m 2 / g, 2.6 m 2 / g, 2.7 m 2 / g, 2.8 m 2 / g, 2.9 m 2 / g or 3 m 2 / g.

[0096] The inventors of the present disclosure have found that when the median particle size and specific surface area of the carbon-based material are within a specific range, the negative electrode active material has excellent kinetic performance, which can ensure that the battery has good fast charging performance and low-temperature cycling performance.

[0097] In the present disclosure, the specific surface area of the carbon-based material can be measured by conventional methods in the art, such as using a NOVA Touch BET tester and measuring by the ASAP 2460 nitrogen adsorption method.

[0098] In the present disclosure, based on the total weight of the negative electrode active material, the content c of the silicon-based material can be 0% < c ≤ 30% (for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%).

[0099] In one example, based on the total weight of the negative electrode active material, the content of the silicon-based material is 6% - 15%.

[0100] The inventors of the present disclosure have found that when the content of the silicon-based material in the negative electrode active material is within a specific range, it can effectively improve the mass energy density of the battery while ensuring the cycling performance of the battery, including high-temperature cycling performance and low-temperature cycling performance.

[0101] In the present disclosure, the thickness of the negative electrode active material layer can be 10 μm - 90 μm, such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm or 90 μm.

[0102] In one embodiment, the thickness of the negative electrode active material layer is 30 μm-60 μm.

[0103] In the present disclosure, the thickness of the negative electrode active material layer refers to the thickness of one side of the negative electrode active material layer.

[0104] In the present disclosure, the negative electrode current collector may include a current collector substrate. The current collector substrate may include copper foil.

[0105] In the present disclosure, the negative electrode current collector may further include a carbon layer. The carbon layer is located on at least one side of the current collector substrate.

[0106] The inventors of the present disclosure have discovered that when the negative electrode current collector includes a carbon layer, on the one hand, it can effectively improve the electronic conductivity of the negative electrode sheet, thereby improving the dynamic performance of the battery; on the other hand, it can enable the negative electrode slurry to be well coated on the negative electrode current collector, improve the adhesive performance, prevent powder loss, and thereby improve the processing performance of the negative electrode sheet and improve production efficiency.

[0107] In the present disclosure, the thickness of the carbon layer may be 0 μm-1.5 μm, for example, 0 μm, 0.5 μm, 1 μm or 1.5 μm. It is understood that when the thickness of the carbon layer is 0 μm, it means that the negative electrode current collector does not contain a carbon layer.

[0108] The inventors of the present disclosure have found that when the thickness of the carbon layer is within a specific range, the bonding performance and the conductive performance can be significantly improved without affecting the ED, which is beneficial to the structural stability of the battery.

[0109] In the present disclosure, the thickness of the carbon layer refers to the thickness of a single side of the carbon layer.

[0110] In the present disclosure, the battery may further include a separator and an electrolyte. Both the separator and the electrolyte may be conventionally used electrolytes in the art.

[0111] It should be noted that the numerical expressions such as "first" and "second" in this disclosure are only used to distinguish different substances or usage methods, and do not represent a difference in order.

[0112] The present disclosure will be described in detail below through examples. The examples described in this disclosure are only a portion of the examples of the present disclosure, not all of the examples. Based on the examples in this disclosure, all other examples obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this disclosure.

[0113] In the following examples, unless otherwise specified, all materials used were commercially available analytical grade.

[0114] The following Group A Preparation Example is used to prepare the first positive electrode active material of the present disclosure.

[0115] Preparation Example A1

[0116] Prepare as follows:

[0117] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.338 and sintered at 820℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1000ppm of Co(OH)2 for a second sintering at a sintering temperature of 700℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 600℃ for 10h to obtain the first positive electrode active material, wherein m1 is 2500ppm, m2 is 1500ppm, the mass ratio of elements Al, W and B is 1.5:2.5:1, Dv 1 10 is 1.624μm, Dv 1 50 is 2.993μm, Dv 1 90 is 6.325μm and the major axis is 1.032μm-3.027μm.

[0118] Preparation Example A2

[0119] Prepare as follows:

[0120] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.473 and sintered at 830℃ for 12h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 2000ppm of Co(OH)2 for a second sintering at a sintering temperature of 720℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 400℃ for 10h to obtain the first positive electrode active material, wherein m1 is 3500ppm, m2 is 2000ppm, the mass ratio of elements Al, W and B is 1:4:1, Dv 1 10 is 1.543μm, Dv 1 50 is 2.984μm, Dv 1 90 is 6.293μm and the major axis is 0.956μm-2.983μm.

[0121] Preparation Example A3

[0122] Prepare as follows:

[0123] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.608 and sintered at 830℃ for 12h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 2000ppm of Co(OH)2 for a second sintering at a sintering temperature of 720℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 400℃ for 10h to obtain the first positive electrode active material, wherein m1 is 4500ppm, m2 is 2500ppm, the mass ratio of elements Al, W and B is 2:1.2:1, Dv 1 10 is 1.632μm, Dv 1 50 is 3.48μm, Dv 1 90 is 6..473μm and the major axis is 1.024μm-3.148μm.

[0124] Preparation Example A4 Group

[0125] This group of preparation examples was carried out according to the preparation example A1, except that the element A' was changed. 1 , specifically:

[0126] Preparation Example A4a, the mass ratio of elements Al, W and B is 0.9:6:1; Dv 1 10 is 1.344μm, Dv 1 50 is 2.733μm, Dv 1 90 is 6.285μm, major axis is 1.011μm-3.046μm;

[0127] Preparation Example A4b, the mass ratio of elements Al, W and B is 5:1:1; Dv 1 10 is 1.473μm, Dv 1 50 is 2.890μm, Dv 1 90 is 6.409μm, major axis is 1.069μm-3.110μm;

[0128] Preparation Example A4c, Element A' 1 It is a combination of elements Al and W, and the mass ratio of elements Al and W is 1:1; Dv 1 10 is 1.523μm, Dv 1 50 is 2.933μm, Dv 190 is 6.449μm, major axis is 1.118μm-3.125μm;

[0129] Preparation Example A4d, Element A' 1 It is a combination of elements Al and B, and the mass ratio of elements Al and B is 1:1; Dv 1 10 is 1.588μm, Dv 1 50 is 2.983μm, Dv 1 90 is 6.503μm and the major axis is 1.186μm-3.121μm.

[0130] Preparation Example A5 Group

[0131] This group of preparation examples was carried out according to Preparation Example A1, except that the element A was changed. 1 and A' 1 The doping amount, specifically:

[0132] Preparation Example A5a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.473, where m1 is 3500ppm, m2 is 500ppm, and Dv 1 10 is 1.732μm, Dv 1 50 is 3.164μm, Dv 1 90 is 6.425μm, major axis is 0.723μm-3.126μm;

[0133] Preparation Example A5b: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.405, where m1 is 3000ppm, m2 is 1000ppm, and Dv 1 10 is 1.739μm, Dv 1 50 is 3.160μm, Dv 1 90 is 6.405μm, major axis is 0.708μm-3.104μm;

[0134] Preparation Example A5c: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2(median particle size Dv 150 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.135, where m1 is 1000ppm, m2 is 3000ppm, and Dv 1 10 is 1.523μm, Dv 1 50 is 3.014μm, Dv 1 90 is 6.92μm and the major axis is 0.701μm-2.932μm.

[0135] Preparation Example A6 Group

[0136] This group of preparation examples was carried out according to Preparation Example A1, except that the element A was changed. 1 The doping amount, specifically:

[0137] Preparation Example A6a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.068, where m1 is 500ppm, m2 is 1500ppm, and Dv 1 10 is 1.628μm, Dv 1 50 is 2.997μm, Dv 1 90 is 6.337μm, major axis is 1.006μm-2.894μm;

[0138] Preparation Example A6b: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:1.148, where m1 is 8500ppm, m2 is 1500ppm, and Dv 1 10 is 1.531μm, Dv 1 50 is 2.884μm, Dv 1 90 is 6.230μm and the major axis is 0.865μm-2.796μm.

[0139] Preparation Example A7

[0140] This preparation example is carried out in accordance with the preparation example A1, except that the particle size and major axis of the first positive electrode active material are changed. Specifically, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02(OH)2 (median particle size Dv50 is 3.75μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.338 and sintered at 800℃ for 12h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1000ppm of Co(OH)2 for a second sintering at a sintering temperature of 700℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 400℃ for 10h to obtain the first positive electrode active material, wherein m1 is 2500ppm, m2 is 1500ppm, the mass ratio of elements Al, W and B is 1.5:2.5:1, Dv 1 10 is 0.984μm, Dv 1 50 is 2.635μm, Dv 1 90 is 5.992μm and the major axis is 0.487μm-2.459μm.

[0141] Preparation Example A8 Group

[0142] This group of preparation examples was carried out with reference to Preparation Example A1, except that the content of element Ni in the first positive electrode active material and the sintering temperature were changed. Specifically:

[0143] Example A8a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75 μm) was replaced by the same mass of Ni 0.6 Co 0.1 Mn 0.3 (OH)2 (median particle size Dv50 is 3.46μm), the sintering temperature is adjusted from 820℃ to 900℃; among them, Dv 1 10 is 1.905μm, Dv 1 50 is 3.346μm, Dv 1 90 is 7.428μm, major axis is 0.523μm-3.248μm;

[0144] Example A8b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75 μm) was replaced by the same mass of Ni 0.83 Co 0.12 Mn 0.05 (OH)2 (median particle size Dv50 is 3.64μm), the sintering temperature is adjusted from 820℃ to 860℃; among them, Dv 1 10 is 2.064μm, Dv 1 50 is 3.427μm, Dv 190 is 7.542μm and the major axis is 0.524μm-3.302μm.

[0145] Preparation Example A9 Group

[0146] This group of preparation examples was carried out with reference to Preparation Example A1, except that the particle size and major axis of the first positive electrode active material were changed. Specifically:

[0147] Example A9a, the sintering temperature is adjusted from 820℃ to 880℃; wherein Dv 1 10 is 2.132μm, Dv 1 50 is 4.482μm, Dv 1 90 is 8.635μm, major axis is 0.764μm-3.492μm;

[0148] Example A9b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75 μm) was replaced by the same mass of Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.027μm), the sintering temperature is adjusted from 820℃ to 880℃; 1 10 is 1.072μm, Dv 1 50 is 2.391μm, Dv 1 90 is 6.012μm and the major axis is 0.506μm-2.016μm.

[0149] Preparation Example A10

[0150] Refer to Preparation Example A1, with the following changes: Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 3.75 μm) was replaced by the same mass of Ni 0.95 Co 0.03 Mn 0.02 (OH)2 (median particle size Dv50 is 3.018 μm), where Dv 1 10 is 1.068μm, Dv 1 50 is 2.941μm, Dv 1 90 is 6.153μm, and the major axis is 0.514μm-2.247μm.

[0151] The following Group B Preparation Example is used to prepare the second positive electrode active material of the present disclosure.

[0152] Preparation Example B1

[0153] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.203 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 1500ppm, m4 is 3000ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 4.725μm, Dv 2 50 is 9.567μm, Dv 2 90 is 18.036μm and the major axis is 8.014μm-10.536μm.

[0154] Preparation Example B2

[0155] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.135 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 1000ppm, m4 is 2000ppm, the mass ratio of elements Al, W and B is 1:2:1, Dv 2 10 is 4.749μm, Dv 2 50 is 9.759μm, Dv 2 90 is 18.273μm and the major axis is 8.196μm-10.617μm.

[0156] Preparation Example B3

[0157] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02(OH)2 (median particle size Dv50 is 7.236μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.270 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 2000ppm, m4 is 4000ppm, the mass ratio of elements Al, W and B is 1.5:1:1, Dv 2 10 is 3.672μm, Dv 2 50 is 7.703μm, Dv 2 90 is 12.104μm and the major axis is 3.114μm-7.618μm.

[0158] Preparation Example B4

[0159] This group of preparation examples was carried out according to the preparation example B1, except that the element A' was changed. 2 , specifically:

[0160] Preparation Example B4a, the mass ratio of elements Al, W and B is 1:4:1, Dv 2 10 is 4.728μm, Dv 2 50 is 9.605μm, Dv 2 90 is 18.148μm, major axis is 8.125μm-10.609μm;

[0161] Preparation Example B4b, the mass ratio of elements Al, W and B is 3:1:1, Dv 2 10 is 4.749μm, Dv 2 50 is 9.993μm, Dv 2 90 is 18.618μm, major axis is 8.248μm-10.732μm;

[0162] Preparation Example B4c, Element A' 2 It is a combination of elements Al and W, and the mass ratio of elements Al and W is 1:1, Dv 2 10 is 4.743μm, Dv 2 50 is 9.982μm, Dv 2 90 is 18.604μm, major axis is 8.225μm-10.719μm;

[0163] Preparation Example B4d, Element A' 2 It is a combination of elements Al and B, and the mass ratio of elements Al and B is 1:1, Dv 210 is 4.792μm, Dv 2 50 is 9.914μm, Dv 2 90 is 18.612μm and the major axis is 8.295μm-10.789μm.

[0164] Preparation Example B5

[0165] This group of preparation examples was carried out according to the preparation example B1, except that the element A was changed. 2 and A' 2 The doping amount, specifically:

[0166] Preparation Example B5a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.473 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 3500ppm, m4 is 1000ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 5.132μm, Dv 2 50 is 11.757μm, Dv 2 90 is 19.296μm, major axis is 8.564μm-11.725μm;

[0167] Preparation Example B5b: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.027 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 200ppm, m4 is 4300ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 4.932μm, Dv 2 50 is 10.924μm, Dv2 90 is 19.184μm and the major axis is 8.472μm-10.649μm.

[0168] Preparation Example B6 Group

[0169] This group of preparation examples was carried out according to the preparation example B1, except that the element A was changed. 2 The doping amount, specifically:

[0170] Preparation Example B6a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.068 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 500ppm, m4 is 3000ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 4.826μm, Dv 2 50 is 10.838μm, Dv 2 90 is 19.034μm, major axis is 8.349μm-10.527μm;

[0171] Preparation Example B6b: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.946 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 7000ppm, m4 is 3000ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 4.007μm, Dv 2 50 is 9.547μm, Dv 2 90 is 18.012μm and the major axis is 8.093μm-10.501μm.

[0172] Preparation Example B7

[0173] This preparation example is carried out in accordance with the preparation example B1, except that the particle size and major axis of the second positive electrode active material are changed. Specifically, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 4.920μm) and ZrO2 are mixed in a mass ratio of 76.432:100:0.203 and sintered at 770℃ for 15h; the material is taken out, crushed, passed through a 200-mesh sieve, and then mixed with 1500ppm of Co(OH)2 for a second sintering at a sintering temperature of 680℃ for 10h; the material is taken out, mixed with Al2O3, WO3 and H3BO3, and sintered for a third time at a temperature of 450℃ for 10h to obtain a second positive electrode active material, wherein m3 is 1500ppm, m4 is 3000ppm, the mass ratio of elements Al, W and B is 1.2:1.5:1, Dv 2 10 is 2.394μm, Dv 2 50 is 5.215μm, Dv 2 90 is 9.306μm and the major axis is 0.984μm-8.272μm.

[0174] Preparation Example B8

[0175] This group of preparation examples was carried out with reference to Preparation Example B1, except that the content of element Ni in the second positive electrode active material and / or the sintering temperature were changed. Specifically:

[0176] Example B8a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.6 Co 0.1 Mn 0.3 (OH)2 (median particle size Dv50 is 9.246 μm); the sintering temperature is adjusted from 770℃ to 800℃; wherein, Dv 2 10 is 4.306μm, Dv 2 50 is 9.527μm, Dv 2 90 is 18.129μm, major axis is 8.002μm-10.511μm;

[0177] Example B8b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.83 Co0.12 Mn 0.05 (OH)2 (median particle size Dv50 is 9.276 μm); among them, Dv 2 10 is 4.274μm, Dv 2 50 is 9.603μm, Dv 2 90 is 18.084μm and the major axis is 8.061μm-10.237μm.

[0178] Preparation Example B9 Group

[0179] This group of preparation examples was carried out with reference to Preparation Example B1, except that the particle size and major axis of the second positive electrode active material were changed. Specifically:

[0180] Example B9a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 15.935 μm); among them, Dv 2 10 is 6.743μm, Dv 2 50 is 17.259μm, Dv 2 90 is 19.992μm, major axis is 8.247μm-14.937μm;

[0181] Example B9b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 5.536μm); among them, Dv 2 10 is 2.401μm, Dv 2 50 is 5.674μm, Dv 2 90 is 9.382μm, major axis is 0.986μm-8.293μm;

[0182] Example B9c, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 13.506 μm); among them, Dv2 10 is 2.206μm, Dv 2 50 is 13.472μm, Dv 2 90 is 16.742μm and the major axis is 0.106μm-14.607μm.

[0183] Preparation Example B10

[0184] Refer to Preparation Example B1, with the following changes:

[0185] Example B10a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (median particle size Dv50 is 9.248 μm) was replaced by the same mass of Ni 0.95 Co 0.03 Mn 0.02 (OH)2 (Dv50 is 10.274μm); among them, Dv 2 10 is 2.628μm, Dv 2 50 is 10.442μm, Dv 2 90 is 18.329μm, and the major axis is 1.219μm-12.603μm.

[0186] Test Case I

[0187] Long axis test

[0188] The positive electrode active materials prepared in Preparation Example Group A and Preparation Example Group B were subjected to a long axis test. The specific method is as follows:

[0189] Using SEM, a field of view with a size of 50 μm × 50 μm was randomly selected in the mirror image, the long axis of the positive electrode active material was measured within this range, and the long axis range was recorded.

[0190] The following examples are provided to illustrate the batteries of the present disclosure.

[0191] Example 1

[0192] Prepare the battery as follows:

[0193] (1) Preparation of positive electrode sheet

[0194] The positive electrode active material (see Table 1 for details), conductive carbon black (SP), carbon nanotubes and polyvinylidene fluoride were mixed uniformly in a mass ratio of 97:0.5:1.3:1.2 to prepare a positive electrode slurry, which was evenly coated on aluminum foil. After rolling baking in a 100°C oven (rolling belt 2m / min) and vacuum baking at 85°C for 20h, the positive electrode sheets were cold pressed and cut. The compacted density of the positive electrode sheets was 3.45g / cm 3 .

[0195] (2) Preparation of negative electrode sheet

[0196] The negative electrode active material [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m 2 / g) and silicon oxide (silicon-silicon oxide composite material, gram capacity ≥1260mAh / g) are mixed in a mass ratio of 94:6], conductive carbon black, carboxymethyl cellulose and styrene-butadiene rubber are mixed in a mass ratio of 97:1:0.8:1.2 to prepare a negative electrode slurry, which is evenly coated on a copper foil containing a carbon layer on both sides (the thickness of the single-sided carbon layer is 1μm). After rolling baking in a 10m oven at 100℃ (rolling belt 2m / min) and vacuum baking at 85℃ for 20h, the negative electrode sheet is cold pressed and cut to obtain a negative electrode sheet. The thickness of the negative electrode active material layer is 50μm, and the compaction density of the negative electrode sheet is 1.55g / cm 3 .

[0197] (3) Preparation of batteries

[0198] The electrolyte is a mixed solution of 1 mol / L LiPF6 and ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a volume ratio of 1:1:1, and 1.5% by mass of 1,3-propane sultone (PS) and 7% by mass of fluoroethylene carbonate (FEC) are added; the diaphragm is a polyethylene diaphragm; after assembling into a soft-pack full battery, the battery test is carried out using an ArbinBT2000 battery tester, and the voltage range is set to 4.25V-2.5V.

[0199] Example 2

[0200] Refer to Example 1, the differences are as follows:

[0201] (1) Preparation of positive electrode sheet: positive electrode active material (see Table 1 for details);

[0202] (2) Preparation of negative electrode sheet: The negative electrode active material is [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m 2 / g) and silicon-oxygen (silicon-silicon oxide composite material, gram capacity ≥1260mAh / g) were mixed in a mass ratio of 90:10].

[0203] Example 3

[0204] Refer to Example 1, the differences are as follows:

[0205] (1) Preparation of positive electrode sheet: positive electrode active material (see Table 1 for details);

[0206] (2) Preparation of negative electrode sheet: The negative electrode active material is [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m 2 / g) and silicon-oxygen (silicon-silicon oxide composite material, gram capacity ≥1260mAh / g) were mixed in a mass ratio of 85:15].

[0207] Example 4 Group

[0208] This group of examples was carried out with reference to Example 1, except that the mass ratio between the first positive electrode active material and the second positive electrode active material in the positive electrode active material was changed, as shown in Table 1.

[0209] Example 5 Group

[0210] This group of examples is carried out in accordance with Example 1, except that the first positive electrode active material (verification element A' 1 For details, see Table 1.

[0211] Example 6

[0212] This group of examples is carried out in accordance with Example 1, except that the second positive electrode active material (verification element A' 2 For details, see Table 1.

[0213] Example 7 Group

[0214] This group of examples is carried out with reference to Example 1, except that the first positive electrode active material is changed (to verify the effect of the change in m4 / m2), as shown in Table 1 for details.

[0215] Example 8

[0216] The same procedure was followed as in Example 1, except that the second positive electrode active material was changed (to verify the effect of the change in m4 / m2). See Table 1 for details.

[0217] Example 9 Group

[0218] This group of examples is carried out with reference to Example 1, except that the first positive electrode active material is changed (to verify the effect of the change of m1+m2), as shown in Table 1 for details.

[0219] Example 10 Group

[0220] This group of examples is carried out with reference to Example 1, except that the second positive electrode active material is changed (to verify the effect of the change of m3+m4), as shown in Table 1 for details.

[0221] Example 11 Group

[0222] This group of examples was carried out with reference to Example 1, except that the first positive electrode active material or the second positive electrode active material was changed (to verify the effect of the change in the particle size of the first positive electrode active material or the second positive electrode active material). See Table 1 for details.

[0223] Example 12

[0224] The method was carried out in accordance with Example 1, except that the content of the silicon-based material in the negative electrode active material was changed. The specific negative electrode active material was [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m 2 / g) and silicon-oxygen (silicon-silicon oxide composite material, gram capacity ≥1260mAh / g) were mixed in a mass ratio of 80:20].

[0225] Example 13 Group

[0226] This group of examples is carried out with reference to Example 1, except that the compaction density of the positive electrode sheet is changed. Specifically:

[0227] Example 13a, the compacted density of the positive electrode sheet is 3.3 g / cm 3 ;

[0228] Example 13b, the compacted density of the positive electrode sheet is 3.6 g / cm 3 ;

[0229] Example 13c, the compacted density of the positive electrode sheet is 3.25 g / cm 3 ;

[0230] Example 13d, the compacted density of the positive electrode sheet is 3.7 g / cm 3 .

[0231] Example 14 Group

[0232] This group of examples was carried out with reference to Example 1, except that the first positive electrode active material and the second positive electrode active material were changed (to verify the effects of changes in the content of element Ni in the first positive electrode active material and the content of element Ni in the second positive electrode active material). See Table 1 for details.

[0233] Example 15 Group

[0234] This group of examples is carried out with reference to Example 1, except that the first positive electrode active material and the second positive electrode active material are changed (to verify the effect of the change of P1 / P2 / P2-P1), as shown in Table 1 for details.

[0235] Example 16 group

[0236] This group of examples is carried out with reference to Example 1, except that the first positive electrode active material and the second positive electrode active material are changed (verification (X 104 -X 003 ) / (T DSC ×I 003 / I 104 ) are shown in Table 1 for details.

[0237] Example 17 Group

[0238] This group of examples is carried out with reference to Example 1, except that the negative electrode active material is changed, specifically:

[0239] In Example 17a, artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m 2 / g) was replaced with the same mass of artificial graphite (median particle size Dv50 = 13.674 μm and specific surface area 1.138 m 2 / g);

[0240] In Example 17b, the silicon-silicon oxide composite material in the negative electrode active material (with a gram capacity of ≥1260 mAh / g) is replaced with a silicon-carbon composite material of the same mass (with a gram capacity of ≥1750 mAh / g).

[0241] Comparative Example 1

[0242] The process was carried out in accordance with Example 1, except that the positive electrode active material was the first positive electrode active material prepared in Preparation Example A1.

[0243] Comparative Example 2

[0244] The process was carried out in accordance with Example 1, except that the positive electrode active material was the second positive electrode active material prepared in Preparation Example B1.

[0245] Comparative Example 3

[0246] The same process was carried out as in Example 1, except that the second positive electrode active material was changed. See Table 1 for details.

[0247] Table 1: Note: “ / ” in Table 1 means no data.

[0248] Test Case II

[0249] (1) Volume particle size test

[0250] The positive electrode sheets prepared in the examples and comparative examples were tested for volume particle size, and the results are recorded in Table 2.

[0251] (2) XRD test

[0252] The positive electrode sheets prepared in the examples and comparative examples were subjected to XRD testing, and the results are recorded in Table 2.

[0253] (3)DSC test

[0254] The positive electrode sheets prepared in the examples and comparative examples were subjected to DSC tests, and the results are recorded in Table 2.

[0255] Table 2

[0256] Test Case III

[0257] The batteries prepared in the examples and comparative examples were tested using an Arbin BT2000 battery tester with a voltage range of 4.25 V to 2.5 V. The test results are recorded in Table 3. The specific test method is as follows:

[0258] 45°C cycle test: In a constant temperature environment of 45°C: 1. Stand for 30 minutes; 2. Discharge at a constant current of 1C to the lower limit voltage; 3. Charge at a constant current and constant voltage of 1.5C to the upper limit voltage, with a cut-off current of 0.05C; 4. Discharge at a constant current of 1C to the lower limit voltage; 5. Repeat steps 3-4 for the cycle test, and record the number of cycles until 80% SOH (SOH is the battery health, which can be used to evaluate the health of the battery, that is, the percentage of current capacity to factory capacity);

[0259] 45°C cyclic DCIR test: 1. Stand for 30 minutes; 2. Charge at 1C constant current and constant voltage to the upper limit voltage, with a cut-off current of 0.05C; 3. Discharge at 1C constant current to the lower limit voltage, and record the capacity C0; 4. Charge at 1C constant current and constant voltage to the upper limit voltage; 5. Discharge at 1C constant current to 50% SOC; 6. Stand for 30 minutes; 7. Discharge at 3C for 10 seconds; record the DCIR data, DCIR growth rate = (end DCIR - initial DCIR) / initial DCIR * 100%;

[0260] -10℃ cycle test: In a constant temperature environment of -10℃: 1. Stand for 30 minutes; 2. Discharge at a constant current of 0.33C to the lower limit voltage; 3. Charge at a constant current and constant voltage of 0.5C to the upper limit voltage, with a cut-off current of 0.05C; 4. Discharge at a constant current of 0.33C to the lower limit voltage; 5. Repeat steps 3-4 for cycle test.

[0261] Table 3

[0262] As can be seen from Table 3, compared with Comparative Examples 1 and 2, the embodiment can exhibit excellent kinetic performance, lower internal resistance and excellent cycle performance because the embodiment adopts a mixture of the first positive electrode active material and the second positive electrode active material (the first positive electrode active material can effectively fill the gaps formed by the second active material, so that the positive electrode sheet has excellent structural stability).

[0263] The preferred embodiments of the present disclosure are described in detail above, but the present disclosure is not limited thereto. Within the technical concept of the present disclosure, various simple variations of the technical solution of the present disclosure may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed by the present disclosure and fall within the scope of protection of the present disclosure.

Claims

1. A positive electrode sheet, characterized in that: The positive electrode sheet includes a positive electrode active material, the positive electrode active material includes a first positive electrode active material and a second positive electrode active material; the first positive electrode active material includes single crystal particles, the second positive electrode active material includes polycrystalline particles; the first positive electrode active material includes element A 1 and A' 1 The second positive electrode active material includes element A 2 and A' 2 , element A 1 and element A 2 Each independently includes at least one of Sr, Y, Mg, Mo, Zr and Ti; element A' 1 and element A' 2 Each independently includes at least one of W, Al and B; element A' 1 The content of the first positive electrode active material is m2, element A' 2 The content of the second positive electrode active material is m4, satisfying m2≤m4.

2. The positive electrode sheet according to claim 1, wherein: ElementA 1 The content of element A in the first positive electrode active material is m1. 2 The contents m3, m1 and m2 in the second positive electrode active material satisfy 200 ppm≤m1+m2≤10000 ppm, and m3 and m4 satisfy 200 ppm≤m3+m4≤10000 ppm; Preferably, 2000ppm≤m1+m2≤10000ppm; more preferably, 4000ppm≤m1+m2≤7000ppm; And / or, 2000ppm≤m3+m4≤10000ppm; preferably, 3000ppm≤m3+m4≤6000ppm.

3. The positive electrode sheet according to claim 1 or 2, wherein: 1≤m4 / m2≤6; preferably, 1≤m4 / m2≤2; and / or, m2 is 1000ppm-3000ppm; preferably, m2 is 1500ppm-2500ppm; And / or, m4 is 1000ppm-4300ppm; preferably, m4 is 2000ppm-4000ppm.

4. The positive electrode sheet according to any one of claims 1 to 3, wherein: ElementA' 1 and element A' 2 All include Al, W and B; Preferably, element A' 1 The mass ratio of elements Al, W and B is (0.9-5): (1-6): 1; more preferably (1-2): (1.2-4): 1; Preferably, element A' 2 The mass ratio of elements Al, W and B is (1-3): (1-4): 1; more preferably (1-1.5): (1-2):

1.

5. The positive electrode sheet according to any one of claims 1 to 4, wherein: The particle size Dv of the first positive electrode active material 1 10. Dv 1 50 and Dv 1 90 satisfies: 1μm≤Dv 1 10≤3μm, 2.5μm≤Dv 1 50≤5μm, 6μm≤Dv 1 90≤9μm; And / or, the particle size Dv of the second positive electrode active material 2 10. Dv 2 50 and Dv 2 90 satisfies: 3μm≤Dv 2 10≤13μm, 7μm≤Dv 2 50≤18μm, 10μm≤Dv 2 90≤20μm; Preferably, the first positive electrode active material is filled in the gaps between the second positive electrode active materials.

6. The positive electrode sheet according to any one of claims 1 to 5, wherein: The particle size of the second positive electrode active material satisfies: 3 μm ≤ Dv 2 10≤6μm, 7μm≤Dv 2 50≤13μm, 10μm≤Dv 2 90≤20μm; And / or, the particle size of the second positive electrode active material satisfies: 4 μm ≤ Dv 2 10≤13μm, 7μm≤Dv 2 50≤18μm, 10μm≤Dv 2 90≤20μm.

7. The positive electrode sheet according to any one of claims 1 to 6, wherein: Dv 1 10 <Dv 2 10; Preferably, Dv 1 50 <Dv 2 50; Preferably, Dv 1 90 <Dv 2 90.

8. The positive electrode sheet according to any one of claims 1 to 7, wherein: The first positive electrode active material includes a substance with the chemical formula Li x1 Ni a1 Co b1 Mn c1 A 1 d1 A’ 1 e1 O2, where 1≤x1≤1.08, 0.5≤a1<1, 0<b1≤0.2, 0<c1≤0.2, 0<d1≤0.015, 0<e1≤0.02; preferably, 0.8≤a1<1; And / or, the second positive electrode active material includes a substance with the chemical formula Li x2 Ni a2 Co b2 Mn c2 A 2 d2 A’ 2 e2 O2, where 1≤x2≤1.08, 0.5≤a2<1, 0<b2≤0.2, 0<c2≤0.2, 0<d2≤0.015, 0<e2≤0.02; preferably, 0.8≤a2<1.

9. The positive electrode sheet according to any one of claims 1 to 8, wherein: The long axis of the first positive electrode active material is 0.5 μm-3.5 μm; and / or, the major axis of the second positive electrode active material is 1 μm-15 μm; Preferably, the compaction density of the positive electrode sheet is 3 mg / cm 3 -4mg / cm 3 ; preferably 3.3 mg / cm 3 -3.6mg / cm 3 .

10. The positive electrode sheet according to any one of claims 1 to 9, wherein: The positive electrode sheet is subjected to a volume particle size test, and the test curve has at least two characteristic peaks, the peak value of the first characteristic peak corresponds to a particle size classification of P1, and the peak value of the second characteristic peak corresponds to a particle size classification of P2, satisfying 2μm≤P2-P1≤10μm; Preferably, 1 μm ≤ P1 ≤ 7 μm; Preferably, 5 μm ≤ P2 ≤ 15 μm.

11. The positive electrode sheet according to any one of claims 1 to 10, wherein: The XRD diffraction spectrum of the positive electrode sheet has a 003 crystal plane peak and a 104 crystal plane peak, and the angle value corresponding to the intensity position of the 003 crystal plane peak is X 003 The angle value corresponding to the peak intensity position of the 104 crystal plane is X 104 The ratio of the 003 crystal plane peak intensity to the 104 crystal plane peak intensity is 1 003 / I 104 , satisfying X 003 15°-23°, X 104 43°-45°, I 003 / I 104 is 1-8; And / or, in the DSC spectrum of the positive electrode sheet, the temperature T corresponding to the peak intensity position DSC It is 200℃-250℃.

12. The positive electrode sheet according to any one of claims 1 to 11, wherein: The XRD diffraction spectrum of the positive electrode sheet has a 003 crystal plane peak and a 104 crystal plane peak, and the angle value corresponding to the intensity position of the 003 crystal plane peak is X 003 The angle value corresponding to the peak intensity position of the 104 crystal plane is X 104 The ratio of the 003 crystal plane peak intensity to the 104 crystal plane peak intensity is 1 003 / I 104 In the DSC spectrum of the positive electrode, the temperature corresponding to the peak intensity position is T DSC ;X 003 、X 104 、T DSC and I 003 / I 104 Satisfy 0.01≤(X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.15; Preferably, 0.02≤(X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.

06.

13. A battery, characterized in that: The battery comprises the positive electrode sheet according to any one of claims 1 to 12.

14. The battery according to claim 13, wherein The battery further comprises a negative electrode sheet; the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer located on at least one side of the negative electrode current collector; the negative electrode active material layer comprises a negative electrode active material, and the negative electrode active material comprises at least one of a carbon-based material and a silicon-based material; Preferably, the carbon-based material comprises at least one of natural graphite, artificial graphite, mesophase carbon microsphere graphite, soft carbon and hard carbon; Preferably, the silicon-based material includes at least one of silicon, silicon oxide, silicon carbon and silicon alloy.

15. The battery according to claim 13 or 14, wherein The median particle size Dv50 of the carbon-based material is 9 μm-18 μm, and the specific surface area of ​​the carbon-based material is 0.9 m 2 / g-3m 2 / g; Preferably, based on the total weight of the negative electrode active material, the content c of the silicon-based material is 0%. <c≤30%; Preferably, the negative electrode current collector further comprises a carbon layer; Preferably, the thickness of the carbon layer is 0 μm-1.5 μm.

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