Positive electrode sheet and battery

Abstract

本发明涉及电池领域，具体涉及一种正极片和电池。所述正极片包括正极活性物质，所述正极活性物质包括第一正极活性物质和第二正极活性物质；所述第一正极活性物质包括单晶颗粒，所述第二正极活性物质包括多晶颗粒；所述第一正极活性物质包括元素A1和A’1，所述第二正极活性物质包括元素A2和A’2，元素A1和元素A2各自独立地包括Sr、Y、Mg、Mo、Zr和Ti中的至少一种；元素A’1和元素A’2各自独立地包括W、Al和B中的至少一种；元素A’1在所述第一正极活性物质中的含量为m2，元素A’2在所述第二正极活性物质中的含量为m4，满足m2≤m4。本发明的正极片压实密度高，具有优异的电化学性能。本发明的电池具有优异的能量密度和循环性能以及较低的内阻。

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically to a positive electrode and a battery including the positive electrode. Background Technology

[0002] With the rapid growth in sales of new energy vehicles, the industry's demand for longer driving ranges is also increasing. Currently, ternary lithium-ion batteries, which are capable of large-scale mass production, are attracting significant attention. However, the energy density of mass-produced ternary lithium-ion battery cells is generally less than 300Wh / kg. Therefore, more and more research is focused on improving the energy density of ternary lithium-ion batteries. One mainstream approach is to increase the upper voltage limit of ternary lithium-ion batteries to increase specific capacity, thereby improving the energy density. However, at high voltages, the cycle performance of ternary lithium-ion batteries degrades rapidly. Summary of the Invention

[0003] The purpose of this invention is to overcome the aforementioned problems in the prior art and provide a positive electrode sheet and a battery including the positive electrode sheet. The positive electrode sheet of this invention has a high compaction density and excellent electrochemical performance. The battery including the positive electrode sheet of this invention exhibits excellent energy density and cycle performance, as well as low internal resistance.

[0004] The first aspect of this invention 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, and 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 element independently includes at least one of Sr, Y, Mg, Mo, Zr, and Ti; element A' 1 and element A' 2 Each element independently includes at least one of W, Al, and B; element A' 1 The content of element A' in the first positive electrode active material is m2. 2 The content of the second positive electrode active material is m4, which satisfies m2≤m4.

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

[0006] By employing the above technical solution, the present invention has at least the following advantages compared with the prior art:

[0007] (1) The positive electrode sheet of the present invention has a positive electrode active material with a specific composition and a high compaction density (e.g., greater than 3.3 mg / cm³). 3 It possesses excellent electrochemical performance;

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

[0009] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Attached Figure Description

[0010] Figure 1 The image shown is a scanning electron microscope (SEM) image of the positive electrode sheet in an example of the present invention.

[0011] Figure 2 The image shown is a cross-sectional SEM image of the positive electrode sheet in an example of the present invention.

[0012] Figure 3 The image shown is a cross-sectional SEM image of the positive electrode sheet in an example of the present invention.

[0013] Figure 4 The figure shows the volumetric particle size test curve of the positive electrode in an example of the present invention.

[0014] Figure 5 The image shown is the XRD diffraction pattern of the positive electrode sheet in an example of the present invention.

[0015] Figure 6 The image shown is a DSC spectrum of the positive electrode sheet in an example of the present invention. Detailed Implementation

[0016] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0017] The first aspect of the present invention provides a positive electrode sheet, which may include a positive electrode active material, and 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.

[0018] Currently, ternary cathode materials can be classified into monocrystalline and polycrystalline types based on their microstructure. Due to their different crystal structures, monocrystalline materials have a superior ability to withstand high voltages compared to polycrystalline materials, resulting in higher energy density and cycle stability. Monocrystalline materials have a more uniform internal orientation and fewer grain boundaries, leading to stronger structural stability and fewer side reactions with the electrolyte. This makes them less prone to breakage during battery cycling, resulting in excellent cycle stability. Monocrystalline materials can withstand higher voltages, allowing for more lithium-ion insertion and extraction, thus increasing the battery's energy density. Furthermore, the higher mechanical strength of monocrystalline materials results in higher compaction density in the cathode sheet, allowing for the loading of more active material within the same volume, further enhancing energy density. In contrast, polycrystalline materials contain numerous grain boundaries, making them prone to grain boundary cracking and particle breakage during battery cycling. This leads to crystal decomposition and side reactions with the electrolyte, resulting in reduced battery cycle performance and a significant increase in impedance.

[0019] Although single-crystal ternary materials can be used at high voltages, resulting in higher energy density and cycle stability, using them alone as the positive electrode active material leads to increased battery polarization and internal resistance, thus affecting electrical performance. This may be because the primary particle size of single-crystal ternary materials is larger than that of polycrystalline ternary materials, increasing the Li0.05 content. + The transmission distance is limited, leading to battery polarization. The inventors of this invention discovered that using both single-crystal and polycrystalline materials as positive electrode active materials can significantly reduce the battery's internal resistance while maintaining 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 faster diffusion rate of the ions results in better fast-charging performance of the battery, and a lower DCIR growth rate during fast charging.

[0020] like Figure 1 The image shown is a scanning electron microscope (SEM) image of the positive electrode sheet in an example of the present invention. As can be seen from the image, the positive electrode active material includes single-crystal particles and polycrystalline particles, wherein the particles enclosed in the black solid circle are single-crystal particles, and the particles enclosed in the black dashed circle are polycrystalline particles.

[0021] 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.

[0022] In this invention, the terms "monocrystalline" and "polycrystalline" have their conventional meanings in the art. Generally, the term "monocrystalline" refers to primary particles, which are directly composed of individual crystals (e.g., with a particle size of 0.2 μm-5 μm). The term "polycrystalline" refers to secondary particles, which are typically formed by the aggregation of primary particles.

[0023] In this invention, the first positive electrode active material may include element A.1 and A' 1 The second positive electrode active material may include element A. 2 and A' 2 , element A 1 and element A 2 Each element independently includes at least one of Sr, Y, Mg, Mo, Zr, and Ti; element A' 1 and element A' 2 Each element independently includes at least one of W, Al, and B; element A' 1 The content of element A' in the first positive electrode active material is m2. 2 The content of the second positive electrode active material is m4, which satisfies m2≤m4 (i.e. m4 / m2≥1, for example, m4 / m2 equals 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).

[0024] In related technologies, the cycle performance of ternary lithium-ion batteries degrades rapidly under high voltage. The inventors of this invention have discovered that when the first and second positive electrode active materials contain specific elements, the energy density of the battery can be further improved and its internal resistance reduced. Furthermore, these specific elements affect the structural stability of the single-crystal particles. When the content of the specific element in the first positive electrode active material is less than or equal to the content of the specific element in the second positive electrode active material, the adverse effects of the single-crystal particles on the battery's internal resistance can be reduced, thereby improving the battery's cycle performance while ensuring high energy density and low internal resistance.

[0025] In this invention, the ternary lithium-ion battery refers to the positive electrode active material comprising the elements Li, Ni, Co, and Mn. In one example, the positive electrode active material further comprises the elements Li, Ni, Co, and Mn.

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

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

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

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

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

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

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

[0033] In one instance, 1 ≤ m4 / m2 ≤ 6.

[0034] In one instance, 1 ≤ m4 / m2 ≤ 2.

[0035] In this invention, m2 can be 1000ppm-3000ppm, for example, 1000ppm, 1500ppm, 2000ppm, 2500ppm or 3000ppm.

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

[0037] In this invention, m4 can be 1000ppm-4300ppm, for example, 1000ppm, 1500ppm, 2000ppm, 2500ppm, 3000ppm, 3500ppm, 4000ppm or 4300ppm.

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

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

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

[0041] In one instance, element A' 1 It includes Al, W, and B. The mass ratio of elements Al, W, and B can be (0.9-5):(1-6):1, for example, 0.9:1:1, 3:1:1, 5:1:1, 0.9:3:1, 3:3:1, 5:3:1, 0.9:6:1, 3:6:1, or 5:6:1.

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

[0043] In one instance, element A' 2 Including Al, W, and B. The mass ratio of elements Al, W, and B can be (1-3):(1-4):1, for example, 1:1:1, 2:1:1, 3:1:1, 1:2:1, 2:2:1, 3:2:1, 1:4:

[0044] 1, 2:4:1 or 3:4:1.

[0045] In one instance, element A' 2 It includes Al, W, and B, with the mass ratio of elements Al, W, and B being (1-1.5):

[0046] (1-2): 1.

[0047] The inventors of this invention discovered that when element A' 1 In the context of element Al, W, and B, the mass ratio of elements A' is given by the mass ratio of elements A' to B'.2 In this process, 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 reduced.

[0048] In this invention, based on the total weight of the positive electrode active material, the content of the first positive electrode active material can be 10-50% by weight (e.g., 10, 15, 20, 25, 30, 35, 40, 45 or 50% by weight), and the content of the second positive electrode active material can be 50-90% by weight (e.g., 90, 85, 80, 75, 70, 65, 60, 55 or 50% by weight).

[0049] 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% by weight, and the content of the second positive electrode active material is 70-80% by weight.

[0050] The inventors of this invention have discovered that when the contents of the first positive electrode active material and the second positive electrode active material are within a specific range, the single crystal particles can be well filled in the gaps between the polycrystalline particles. On the one hand, this provides support for the polycrystalline structure, resulting in higher compaction density and better cycle performance compared to polycrystalline ternary positive electrode sheets. On the other hand, compared to positive electrode sheets composed of pure single crystals, the positive electrode sheet of this invention can achieve both excellent DCIR and low-temperature performance.

[0051] In related technologies, the specific capacity is typically increased by increasing the Ni content in ternary materials. However, as the Ni content increases, the structure of the ternary material becomes increasingly unstable. When used at high voltages, this leads to a deterioration in the battery's cycle performance, rate performance, and high-temperature storage performance. This is particularly pronounced when the number of Ni atoms in the molecular formula of the positive electrode active material is ≥0.8, resulting in even more significant performance degradation at high voltages. The positive electrode sheet of this invention effectively addresses these problems. The positive electrode active material in this invention has a high Ni content, which allows it to remain stable under high voltage conditions, resulting in higher energy density and cycle life for the battery.

[0052] In this invention, the first positive electrode active material may include the chemical formula Li x1 Ni a1 Co b1 Mn c1 A 1 d1 A' 1 e1 O2 substances, 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。

[0053] In one instance, 0.8 ≤ a1 < 1.

[0054] In this invention, the second positive electrode active material may include the chemical formula Li x2 Ni a2 Co b2 Mn c2 A 2 d2 A' 2 e2 O2 substances, 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。

[0055] In one instance, 0.8 ≤ a2 < 1.

[0056] In this invention, the particle size Dv of the first positive electrode active material 1 10. Dv 1 50 and Dv 1 90 can satisfy: 1μm≤Dv 1 10≤3μm (e.g., Dv) 1 10 represents 1μm, 1.5μm, 2μm, 2.5μm, or 3μm), where 2.5μm ≤ Dv 1 50≤5μm (e.g., Dv) 1 50 (2.5μm, 2.7μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm), 6μm≤Dv 1 90≤9μm (e.g., Dv) 1 90 (in terms of 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm or 9μm).

[0057] In this invention, the particle size Dv of the second positive electrode active material 2 10. Dv 2 50 and Dv 2 90 can satisfy: 3μm≤Dv 2 10≤13μm (e.g., Dv) 2 10 (where 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, or 13μm), 7μm ≤ Dv 2 50≤18μm (e.g., Dv) 2 50 (7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm or 18μm), 10μm ≤ Dv 2 90≤20μm (e.g., Dv) 290 represents 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, or 20μm.

[0058] In one example, the particle size of the second positive electrode active material satisfies: 3μm ≤ Dv 2 10≤6μm, 7μm≤Dv 2 50≤13μm, 10μm≤Dv 2 90≤20μm.

[0059] In one example, the particle size of the second positive electrode active material satisfies: 4μm ≤ Dv 2 10≤13μm, 7μm≤Dv 2 50≤18μm, 10μm≤Dv 2 90≤20μm.

[0060] In this invention, 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 conventional methods in the art, such as calcining the positive electrode sheet in a high-temperature furnace at 450°C for 2 hours, collecting the powder, and measuring it by laser method using a Mastersize 3000 (Malvin 3000).

[0061] In this invention, the first positive electrode active material can fill the gaps between the second positive electrode active materials. For example... Figure 2 The image shown is a cross-sectional SEM image of the positive electrode sheet in an example of the present invention. As can be seen from the image, the first positive electrode active material fills the gaps between the second positive electrode active materials.

[0062] In one instance, Dv 1 10 <Dv 2 10.

[0063] In one instance, Dv 1 50 <Dv 2 50.

[0064] In one instance, Dv 1 90 <Dv 2 90.

[0065] The inventors of this invention have 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 fill the voids formed by the second active material relatively uniformly. At this time, the second positive electrode active material can be well supported, so that the positive electrode sheet has a suitable compaction density, thereby improving the energy density of the battery. Furthermore, the voids between the second positive electrode active materials are effectively filled, which can significantly reduce the erosion of the surface of the second positive electrode active material by the electrolyte, weaken the occurrence of side reactions between the positive electrode sheet and the electrolyte, and thus improve the cycle stability of the battery.

[0066] In this invention, the long axis of the first positive electrode active material can 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 can 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. Figure 3 The image shown is a cross-sectional SEM image of the positive electrode sheet in an example of the present invention. As can be seen from the image, 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.

[0067] In one example, the long axis of the second positive electrode active material is 1 μm-8 μm.

[0068] In one example, the long axis of the second positive electrode active material is 8 μm-15 μm.

[0069] The inventors of this invention 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 fill the gaps formed by the second active material relatively uniformly. At this time, the second positive electrode active material can be well supported, so that the positive electrode sheet has a suitable compaction density, thereby improving the energy density of the battery. Furthermore, the gaps between the second positive electrode active materials are effectively filled, which can significantly reduce the erosion of the surface of the second positive electrode active material by the electrolyte, weaken the occurrence of side reactions between the positive electrode sheet and the electrolyte, and thus improve the cycle stability of the battery.

[0070] In this invention, the major axis of the first positive electrode active material or the major 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. This distance can be obtained by conventional methods in the art, such as measurement using SEM.

[0071] In this invention, the compaction density of the positive electrode sheet can be 3 mg / cm³. 3 -4mg / cm 3 For example, 3 mg / cm 3 3.1 mg / cm 3 3.2 mg / cm 3 3.3 mg / cm 3 3.4 mg / cm 3 3.5 mg / cm 3 3.6 mg / cm 3 3.7 mg / cm 3 3.8 mg / cm 3 3.9 mg / cm 3 Or 4mg / cm 3 .

[0072] In one example, the compaction density of the positive electrode is 3.3 mg / cm³. 3 -3.6mg / cm 3 .

[0073] In this invention, the positive electrode sheet is subjected to volumetric particle size testing. The test curve has at least two characteristic peaks, where the peak value of the first characteristic peak corresponds to a particle size classification P1, and the peak value of the second characteristic peak corresponds to a particle size classification P2, satisfying 2μm≤P2-P1≤10μm (for example, P2-P1 equals 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, or 10μm). Figure 4 The figure shows the volumetric particle size test curve of the positive electrode in an example of the present invention. It can be seen from the figure that 2μm≤P2-P1≤10μm.

[0074] The inventors of this invention have discovered that when P2-P1 is within a specific range, the positive electrode can have a good lithium-ion diffusion path and tortuosity, which is beneficial to the wetting 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), which is beneficial to the overall structural stability and ductility of the negative electrode, thereby improving the rate performance of the positive electrode.

[0075] In this invention, 1μm ≤ P1 ≤ 7μm (e.g., 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, or 7μm). 5μm ≤ P2 ≤ 15μm (e.g., 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, or 15μm).

[0076] In this invention, the specific method for testing the particle size of the positive electrode sheet is as follows: the positive electrode sheet is placed in a high-temperature furnace at 450°C and calcined for 2 hours, the powder is collected, and the particle size is tested using Mastersize 3000 (Malvin 3000).

[0077] In this invention, the XRD diffraction pattern of the positive electrode 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 peak intensity of the 003 crystal plane to the peak intensity of the 104 crystal plane is I. 003 / I 104 Satisfying X 003 For 15°-23°, X 104 For 43°-45°, I 003 / I 104 The range is 1-8. For example... Figure 5 The figure shows the XRD diffraction pattern of the positive electrode sheet in an example of the present invention. It can be seen from the figure that X... 003 For 15°-23°, X 104 For 43°-45°, I 003 / I 104 The range is 1-8.

[0078] In one instance, X 003 It is 18°-19°.

[0079] In this invention, the temperature T corresponding to the peak intensity position in the DSC spectrum of the positive electrode is... DSC The temperature is 200℃-250℃. For example... Figure 6 The figure shows the DSC spectrum of the positive electrode in an example of the present invention. It can be seen from the figure that the temperature T corresponding to the peak intensity position is... DSC The temperature range is 200℃-250℃.

[0080] In this invention, the DSC spectrum of the positive electrode can be obtained by DSC testing. 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, cut the positive electrode and place it in a crucible, add electrolyte, and use a differential scanning calorimeter for testing.

[0081] The inventors of this invention discovered that when X 003 X 104 T DSC and I 003 / I 104When specific relationships are met, firstly, the positive electrode sheet has an excellent layered structure, which can prevent the collapse of the layered structure due to the dissolution of transition metals, thus giving the positive electrode sheet excellent structural stability during battery cycling; secondly, it can improve the surface structure of the positive electrode active material, prevent electrode sheet differentiation, facilitate better contact with the positive electrode binder, and prevent the active material from peeling off under high temperature conditions; finally, it can not only prevent the positive electrode active material from undergoing side reactions with the electrolyte under high temperature conditions, thus preventing problems such as gas generation, but also ensure that the positive electrode sheet can withstand higher thermal runaway temperatures, giving it excellent thermal stability.

[0082] In this invention, X 003 X 104 T DSC and I 003 / I 104 Satisfying 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.

[0083] In one instance, 0.02 ≤ (X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.1.

[0084] In one instance, 0.02 ≤ (X 104 -X 003 ) / (T DSC ×I 003 / I 104 )≤0.06.

[0085] In this invention, the positive electrode sheet may include a positive current collector and a positive active material layer on at least one side surface of the positive current collector, the positive active material layer comprising the positive active material. The positive active material layer may also include a positive conductive agent and a positive binder. The positive conductive agent may include, for example, at least one selected from conductive carbon black, acetylene black, Ketjen black, conductive graphite, carbon nanotubes, metal powder, and carbon fiber. The positive binder may include, for example, at least one selected from polymethyl methacrylate, sodium carboxymethyl cellulose, styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene oxide.

[0086] In one example, the positive electrode includes a positive current collector and positive active material layers on both sides of the positive current collector.

[0087] The positive electrode of this invention has a high compaction density and excellent electrochemical performance.

[0088] A second aspect of the present invention provides a battery comprising the positive electrode sheet described in the first aspect of the present invention.

[0089] In this invention, the battery may further include a negative electrode. The negative electrode may include a negative current collector and a layer of negative active material located on at least one side surface of the negative current collector.

[0090] In one example, the negative electrode sheet includes a negative current collector and negative active material layers located on both sides of the negative current collector.

[0091] Related technologies typically increase the specific capacity of the negative electrode by adding silicon-based materials to the negative electrode, thereby improving the battery's energy density. When the structure of the positive electrode active material is unstable, numerous side reactions occur under high voltage conditions. These side reactions occur throughout the battery system, including the positive electrode, negative electrode, and separator, accelerating the degradation of battery performance. This degradation is particularly pronounced when the negative electrode includes silicon-based materials, primarily because silicon-based negative electrodes exhibit poorer kinetics compared to those containing only carbon-based materials, resulting in a more significant deterioration effect. The battery of this invention effectively addresses these problems, achieving both high energy density and excellent cycle life.

[0092] In this invention, the negative electrode active material layer may include a negative electrode active material. The negative electrode active material may include at least one of carbon-based materials and silicon-based materials. The carbon-based material may include at least one of natural graphite, artificial graphite, mesophase carbon microsphere graphite, soft carbon, and hard carbon. The silicon-based material may include at least one of silicon, silicon oxide, silicon-carbon, and silicon alloys. The silicon oxide may include, for example, silicon oxides. The silicon-carbon may include, for example, composite materials of carbon and silicon.

[0093] In one example, the negative electrode active material includes carbon-based materials and silicon-based materials.

[0094] In one example, the carbon-based material includes at least one of artificial graphite and natural graphite.

[0095] In one instance, the carbon-based material includes artificial graphite.

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

[0097] In this invention, the median particle size Dv50 of the carbon-based material can be 9 μm-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 can be 0.9 m². 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, 1.8m 2 / g, 1.9m 2 / g、2m 2 / g、2.1m 2 / g, 2.2m 2 / g, 2.3m 2 / g, 2.4m 2 / g, 2.5m 2 / g, 2.6m 2 / g, 2.7m 2 / g, 2.8m 2 / g, 2.9m 2 / g or 3m 2 / g.

[0098] In this invention, the specific surface area of ​​the carbon-based material can be obtained by conventional methods in the art, such as using a NOVA Touch BET tester and measuring it by the ASAP 2460 nitrogen adsorption method.

[0099] The inventors of this invention have discovered that when the content of silicon-based materials in the negative electrode active material is within a specific range, it is possible to effectively improve the mass energy density of the battery while ensuring the battery's cycle performance, including high-temperature cycle performance and low-temperature cycle performance.

[0100] In the present invention, based on the total weight of the negative electrode active material, the content c of the silicon-based material may 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%).

[0101] In one example, based on the total weight of the negative electrode active material, the content of the silicon-based material is 6% - 15%.

[0102] In the present invention, the thickness of the negative electrode active material layer may 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.

[0103] In one example, the thickness of the negative electrode active material layer is 30 μm - 60 μm.

[0104] In the present invention, the thickness of the negative electrode active material layer refers to the single-layer thickness of the negative electrode active material layer.

[0105] In the present invention, the negative electrode current collector may include a current collector substrate. The current collector substrate may include a copper foil.

[0106] In the present invention, the negative electrode current collector may further include a carbon layer. The carbon layer is located on at least one surface of the current collector substrate.

[0107] The inventors of the present invention found 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 enhancing the kinetic 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 the occurrence of powder falling, and further enhance the processing performance of the negative electrode sheet and the production efficiency.

[0108] In the present invention, the thickness of the carbon layer may be 0 - 1.5 μm, such as 0, 0.5 μm, 1 μm or 1.5 μm. It can be understood that when the thickness of the carbon layer is 0, it means that there is no carbon layer.

[0109] The inventors of the present invention found that when the thickness of the carbon layer is within a specific range, it can significantly improve the bonding performance and conductivity without affecting ED, which is beneficial to the structural stability of the battery.

[0110] In this invention, the thickness of the carbon layer refers to the thickness of a single layer of the carbon layer.

[0111] In this invention, the battery may further include a separator and an electrolyte. Both the separator and the electrolyte can be electrolytes conventionally used in the art.

[0112] It should be noted that the numerical designations such as "first" and "second" in this invention are only used to distinguish different substances or methods of use, and do not represent a difference in order.

[0113] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0114] In the following examples, unless otherwise specified, all materials used are commercially available analytical grade.

[0115] The following preparation examples (Group A) are used to prepare the first positive electrode active material of the present invention.

[0116] Preparation Example A1

[0117] Prepare according to the following steps:

[0118] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.338 and sintered at 820℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1000 ppm Co(OH)₂ and sintered a second time at 700℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 600℃ for 10 h to obtain the first positive electrode active material, where m1 is 2500 ppm, m2 is 1500 ppm, and the mass ratio of Al, W, and B is 1.5:2.5:1. 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.

[0119] Preparation Example A2

[0120] Prepare according to the following steps:

[0121] LiOH·H2O, Ni0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.473 and sintered at 830℃ for 12 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 2000 ppm Co(OH)₂ and sintered a second time at 720℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 400℃ for 10 h to obtain the first positive electrode active material, where m1 is 3500 ppm, m2 is 2000 ppm, and the mass ratio of Al, W, and B is 1:4:1. 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.

[0122] Preparation Example A3

[0123] Prepare according to the following steps:

[0124] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.608 and sintered at 830℃ for 12 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 2000 ppm Co(OH)₂ and sintered a second time at 720℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 400℃ for 10 h to obtain the first positive electrode active material, where m1 is 4500 ppm, m2 is 2500 ppm, and the mass ratio of Al, W, and B is 2:1.2:1. Dv₀ is 3.75 μm. 1 10 is 1.632μm, Dv 1 50 is 3.48μm, Dv 1 90 has a diameter of 6.473 μm and a major axis of 1.024 μm-3.148 μm.

[0125] Preparation Example A4 Group

[0126] The preparation examples in this group were carried out in accordance with preparation example A1, except that element A' was changed. 1 Specifically:

[0127] Preparation example A4a, the mass ratio of elements Al, W, and B is 0.9:6:1; Dv 110 is 1.344μm, Dv 1 50 is 2.733μm, Dv 1 90 has a diameter of 6.285 μm and a major axis of 1.011 μm-3.046 μm;

[0128] 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 has a diameter of 6.409 μm and a major axis of 1.069 μm-3.110 μm;

[0129] Preparation example A4c, element A' 1 Dv is a combination of elements Al and W, with a mass ratio of Al to W of 1:1; 1 10 is 1.523μm, Dv 1 50 is 2.933μm, Dv 1 90 has a diameter of 6.449 μm and a major axis of 1.118 μm-3.125 μm;

[0130] Preparation example A4d, element A' 1 Dv is a combination of elements Al and B, with a mass ratio of Al to B of 1:1; 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.

[0131] Preparation Example A5 Group

[0132] The preparation examples in this group were carried out in accordance with preparation example A1, except that element A' was changed. 1 The doping amount, specifically:

[0133] Preparation Example A5a: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.473, where m1 was 3500 ppm, m2 was 500 ppm, and Dv 1 10 is 1.732μm, Dv 1 50 is 3.164μm, Dv 1 90 has a diameter of 6.425 μm and a major axis of 0.723 μm-3.126 μm;

[0134] Preparation example A5b, LiOH·H2O, Ni 0.92Co 0.06 Mn 0.02 (OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.405, where m1 was 3000 ppm, m2 was 1000 ppm, and Dv 1 10 is 1.739μm, Dv 1 50 is 3.160μm, Dv 1 90 has a diameter of 6.405 μm and a major axis of 0.708 μm-3.104 μm;

[0135] Preparation example A5c, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)2(Dv 1 50 (3.75 μm) and ZrO2 were mixed at a mass ratio of 76.432:100:0.135, where m1 was 1000 ppm, m2 was 3000 ppm, 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.

[0136] Preparation Example A6 Group

[0137] The preparation examples in this group were carried out in accordance with preparation example A1, except that element A was changed. 1 The doping amount, specifically:

[0138] Preparation Example A6a: LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.068, where m1 was 500 ppm, m2 was 1500 ppm, and Dv 1 10 is 1.628μm, Dv 1 50 is 2.997μm, Dv 1 90 has a diameter of 6.337 μm and a major axis of 1.006 μm-2.894 μm;

[0139] Preparation example A6b, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 (OH)₂ (Dv50 is 3.75 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:1.148, where m1 was 8500 ppm, m2 was 1500 ppm, and Dv1 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.

[0140] Preparation Example A7

[0141] This preparation example is carried out in accordance with Preparation Example A1, except that the particle size and long axis of the first positive electrode active material are changed. Specifically, LiOH·H2O and Ni 0.92 Co 0.06 Mn 0.02 (OH)2(Dv 1 50 (3.75 μm) and ZrO2 were mixed at a mass ratio of 76.432:100:0.338 and sintered at 800℃ for 12 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1000 ppm Co(OH)2 and sintered a second time at 700℃ for 10 h. The material was then removed and mixed with Al2O3, WO3, and H3BO3 and sintered a third time at 400℃ for 10 h to obtain the first positive electrode active material, where m1 is 2500 ppm, m2 is 1500 ppm, and the mass ratio of 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 has a diameter of 5.992 μm and a major axis of 0.487 μm-2.459 μm.

[0142] Preparation Example A8 Group

[0143] The preparation examples in this group were carried out in accordance with Preparation Example A1, except that the content of element Ni in the first positive electrode active material and the sintering temperature were changed. Specifically:

[0144] Example A8a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 3.75μm) was replaced with the same mass of Ni. 0.6 Co 0.1 Mn 0.3 (OH)2 (Dv50 is 3.46μm), the sintering temperature was adjusted from 820℃ to 900℃; among which, Dv 1 10 is 1.905μm, Dv 1 50 is 3.346μm, Dv 1 90 has a diameter of 7.428 μm and a major axis of 0.523 μm-3.248 μm;

[0145] Example A8b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 3.75μm) was replaced with the same mass of Ni. 0.83 Co 0.12 Mn 0.05 (OH)2 (Dv50 is 3.64μm), the sintering temperature was adjusted from 820℃ to 860℃; among which, Dv 1 10 is 2.064μm, Dv 1 50 is 3.427μm, Dv 1 90 is 7.542μm, and the major axis is 0.524μm-3.302μm.

[0146] Preparation Example A9 Group

[0147] The preparation examples in this group were carried out in accordance with Preparation Example A1, except that the particle size and long axis of the first positive electrode active material were changed. Specifically:

[0148] Example A9a: The sintering temperature was adjusted from 820℃ to 880℃; wherein, Dv 1 10 is 2.132μm, Dv 1 50 is 4.482μm, Dv 1 90 has a diameter of 8.635 μm and a major axis of 0.764 μm-3.492 μm;

[0149] Example A9b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 3.75μm) was replaced with the same mass of Ni. 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 3.027μm), the sintering temperature was adjusted from 820℃ to 880℃; where Dv 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.

[0150] Preparation Example A10

[0151] The preparation was carried out according to Example A1, with the following specific changes: Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 3.75μm) was replaced with the same mass of Ni. 0.95 Co 0.03 Mn 0.02(OH)2 (Dv50 is 3.018μm), where Dv 1 10 is 1.068μm, Dv 1 50 is 2.941μm, Dv 1 90 is 6.153 μm, and the major axis is 0.514 μm-2.247 μm.

[0152] The following preparation examples (Group B) are used to prepare the second positive electrode active material of the present invention.

[0153] Preparation Example B1

[0154] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.203 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 1500 ppm, m₄ is 3000 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 9.248 μm. 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.

[0155] Preparation Example B2

[0156] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.135 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 1000 ppm, m₄ is 2000 ppm, and the mass ratio of Al, W, and B is 1:2:1. 2 10 is 4.749μm, Dv 2 50 is 9.759μm, Dv2 The diameter of the 90 is 18.273 μm, and the major axis is 8.196 μm-10.617 μm.

[0157] Preparation Example B3

[0158] LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 7.236 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.270 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 2000 ppm, m₄ is 4000 ppm, and the mass ratio of Al, W, and B is 1.5:1:1. 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.

[0159] Preparation Example B4 Group

[0160] The preparation examples in this group were carried out in accordance with Preparation Example B1, except that element A' was changed. 2 Specifically:

[0161] 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 has a diameter of 18.148 μm and a major axis of 8.125 μm-10.609 μm;

[0162] Preparation example B4b, with a mass ratio of Al, W, and B of 3:1:1, Dv 2 10 is 4.749μm, Dv 2 50 is 9.993μm, Dv 2 90 has a diameter of 18.618 μm and a major axis of 8.248 μm-10.732 μm;

[0163] Preparation example B4c, element A' 2 Dv is a combination of elements Al and W, with a mass ratio of Al to W of 1:1. 2 10 is 4.743μm, Dv 250 is 9.982μm, Dv 2 90 has a diameter of 18.604 μm and a major axis of 8.225 μm-10.719 μm;

[0164] Preparation example B4d, element A' 2 Dv is a combination of elements Al and B, with a mass ratio of Al to B of 1:1. 2 10 is 4.792μm, Dv 2 50 is 9.914μm, Dv 2 The diameter of the 90 is 18.612 μm, and the major axis is 8.295 μm-10.789 μm.

[0165] Preparation Example B5 Group

[0166] The preparation examples in this group were carried out in accordance with Preparation Example B1, except that element A' was changed. 2 The doping amount, specifically:

[0167] Preparation example B5a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.473 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 3500 ppm, m₄ is 1000 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 9.248 μm. 2 10 is 5.132μm, Dv 2 50 is 11.757μm, Dv 2 90 has a diameter of 19.296 μm and a major axis of 8.564 μm-11.725 μm;

[0168] Preparation example B5b, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.027 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 200 ppm, m₄ is 4300 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 9.248 μm. 2 10 is 4.932μm, Dv 2 50 is 10.924μm, Dv 2 The diameter of the 90 is 19.184 μm, and the major axis is 8.472 μm-10.649 μm.

[0169] Preparation Example B6 Group

[0170] The preparation examples in this group were carried out in accordance with Preparation Example B1, except that element A was changed. 2 The doping amount, specifically:

[0171] Preparation example B6a, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.068 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 500 ppm, m₄ is 3000 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 9.248 μm. 2 10 is 4.826μm, Dv 2 50 is 10.838μm, Dv 2 90 has a diameter of 19.034 μm and a major axis of 8.349 μm-10.527 μm;

[0172] Preparation example B6b, LiOH·H2O, Ni 0.92 Co 0.06 Mn 0.02Co(OH)₂ (Dv50 is 9.248 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.946 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 7000 ppm, m₄ is 3000 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 9.248 μm. 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.

[0173] Preparation Example B7

[0174] This preparation example is carried out in accordance with Preparation Example B1, except that the particle size and long axis of the second positive electrode active material are changed. Specifically, LiOH·H2O and Ni 0.92 Co 0.06 Mn 0.02 Co(OH)₂ (Dv50 is 4.920 μm) and ZrO₂ were mixed at a mass ratio of 76.432:100:0.203 and sintered at 770℃ for 15 h. The material was then removed, pulverized, and passed through a 200-mesh sieve. It was then mixed with 1500 ppm Co(OH)₂ and sintered a second time at 680℃ for 10 h. The material was then removed and mixed with Al₂O₃, WO₃, and H₃BO₃ and sintered a third time at 450℃ for 10 h to obtain the second positive electrode active material, where m₃ is 1500 ppm, m₄ is 3000 ppm, and the mass ratio of Al, W, and B is 1.2:1.5:1. Dv₀ is 4.920 μm. 2 10 is 2.394μm, Dv 2 50 is 5.215μm, Dv 2 90 has a diameter of 9.306 μm and a major axis of 0.984 μm-8.272 μm.

[0175] Preparation Example B8 Group

[0176] The preparation examples in this group were carried out in accordance with 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:

[0177] Example B8a, Ni 0.92 Co 0.06 Mn 0.02(OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.6 Co 0.1 Mn 0.3 (OH)2 (Dv50 is 9.246μm); the sintering temperature was adjusted from 770℃ to 800℃; among which, Dv 2 10 is 4.306μm, Dv 2 50 is 9.527μm, Dv 2 90 has a diameter of 18.129 μm and a major axis of 8.002 μm-10.511 μm;

[0178] Example B8b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.83 Co 0.12 Mn 0.05 (OH)2 (Dv50 is 9.276 μm); where, Dv 2 10 is 4.274μm, Dv 2 50 is 9.603μm, Dv 2 90 has a diameter of 18.084 μm and a major axis of 8.061 μm-10.237 μm.

[0179] Preparation Example B9 Group

[0180] The preparation examples in this group were carried out in accordance with Preparation Example B1, except that the particle size and long axis of the second positive electrode active material were changed. Specifically:

[0181] Example B9a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 15.935μm); where, Dv 2 10 is 6.743μm, Dv 2 50 is 17.259μm, Dv 2 90 has a diameter of 19.992 μm and a major axis of 8.247 μm-14.937 μm;

[0182] Example B9b, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.92 Co 0.06 Mn0.02 (OH)2 (Dv50 is 5.536μm); where, Dv 2 10 is 2.401μm, Dv 2 50 is 5.674μm, Dv 2 90 has a diameter of 9.382 μm and a major axis of 0.986 μm-8.293 μm;

[0183] Example B9c, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 13.506 μm); where, Dv 2 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.

[0184] Preparation Example B10

[0185] The preparation was carried out in accordance with Preparation Example B1, with the following specific changes:

[0186] Example B10a, Ni 0.92 Co 0.06 Mn 0.02 (OH)2 (Dv50 is 9.248 μm) was replaced with the same mass of Ni. 0.95 Co 0.03 Mn 0.02 (OH)2 (Dv50 is 10.274 μm); where, Dv 2 10 is 2.628μm, Dv 2 50 is 10.442μm, Dv 2 The diameter of 90 is 18.329 μm, and the major axis is 1.219 μm-12.603 μm.

[0187] Test Case I

[0188] Long axis test

[0189] The positive electrode active materials prepared in Preparation Example A and Preparation Example B were subjected to long axis testing, and the specific methods are as follows:

[0190] Using SEM, randomly select a field of view of size 50μm×50μm in the micrograph, measure the long axis of the positive electrode active material within this range, and record the range of the long axis.

[0191] The following examples illustrate the battery of the present invention.

[0192] Example 1

[0193] The battery is prepared according to the following method:

[0194] (1) Preparation of positive electrode sheet

[0195] The positive electrode active material (see Table 1 for details), conductive carbon black (SP), carbon nanotubes, and polyvinylidene fluoride were mixed evenly in a mass ratio of 97:0.5:1.3:1.2 to prepare a positive electrode slurry. This slurry was then uniformly coated onto aluminum foil and subjected to rolling baking at 100℃ in a 10m oven (rolling belt 2m / min) followed by vacuum baking at 85℃ for 20 hours. The resulting positive electrode sheet was then cold-pressed and slit, yielding a compacted density of 3.45 g / cm³. 3 .

[0196] (2) Preparation of negative electrode sheet

[0197] The negative electrode active material [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m²)] was used. 2 [A mixture of silicon-silicon oxide composite material (specific capacity ≥ 1260 mAh / g) and silica (silicon-silicon suboxide composite material, specific capacity ≥ 1260 mAh / g) at a mass ratio of 94:6; conductive carbon black, carboxymethyl cellulose, and styrene-butadiene rubber at a mass ratio of 97:1:0.8:1.2 was mixed evenly to prepare a negative electrode slurry. This slurry was uniformly coated onto copper foil containing carbon layers on both sides (the thickness of the carbon layer on one side was 1 μm). After being baked in a 10 m oven at 100 °C with a rolling speed of 2 m / min, and then vacuum baked at 85 °C for 20 h, the negative electrode sheet was cold-pressed and slit to obtain a negative electrode sheet with a negative electrode active material layer thickness of 50 μm and a compaction density of 1.55 g / cm³.] 3 .

[0198] (3) Battery fabrication

[0199] The electrolyte was a 1 mol / L mixture of LiPF6 and ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of 1:1:1, with the addition of 1.5% by mass of 1,3-propanesulfonyl lactone (PS) and 7% by mass of fluoroethylene carbonate (FEC); the separator was a polyethylene separator; after assembling into a pouch cell, the cell was tested using an Arbin BT2000 battery tester, with the voltage range set at 4.25V-2.5V.

[0200] Example 2

[0201] The procedure is the same as in Example 1, with the following specific differences:

[0202] (1) Preparation of positive electrode sheet: positive electrode active material (see Table 1 for details);

[0203] (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 m²)]. 2 ( / g) and silicon oxide (silicon-silicon suboxide composite material, specific capacity ≥1260mAh / g) are mixed at a mass ratio of 90:10.

[0204] Example 3

[0205] The procedure is the same as in Example 1, with the following specific differences:

[0206] (1) Preparation of positive electrode sheet: positive electrode active material (see Table 1 for details);

[0207] (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 m²)]. 2 ( / g) and silicon oxide (silicon-silicon suboxide composite material, specific capacity ≥1260mAh / g) are mixed at a mass ratio of 85:15.

[0208] Example 4 group

[0209] This set of embodiments is based on Embodiment 1, except that the mass ratio between the first positive electrode active material and the second positive electrode active material is changed, as shown in Table 1.

[0210] Example 5 group

[0211] This set of embodiments is based on Embodiment 1, except that the first positive electrode active material (verification element A') is changed. 1 (The impact of the changes) is detailed in Table 1.

[0212] Example 6 group

[0213] This set of embodiments is based on Embodiment 1, except that the second positive electrode active material (verification element A') is changed. 2 (The impact of the changes) is detailed in Table 1.

[0214] Example 7 group

[0215] This set of embodiments is based on Embodiment 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.

[0216] Example 8

[0217] The procedure was carried out in accordance with Example 1, except that the second positive electrode active material was changed (to verify the effect of the change in m4 / m2), as shown in Table 1.

[0218] Example 9 group

[0219] This set of embodiments is based on Embodiment 1, except that the first positive electrode active material is changed (to verify the effect of changing m1+m2), as shown in Table 1.

[0220] Example 10 group

[0221] This set of embodiments is based on Embodiment 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.

[0222] Example 11 group

[0223] This set of embodiments is based on Embodiment 1, except that the first positive electrode active material or the second positive electrode active material is changed (to verify the effect of changing the particle size of the first positive electrode active material or the particle size of the second positive electrode active material), as shown in Table 1.

[0224] Example 12

[0225] The procedure was carried out in accordance with Example 1, except that the content of silicon-based material in the negative electrode active material was changed. Specifically, the negative electrode active material was [artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m²)]. 2 ( / g) and silicon oxide (silicon-silicon suboxide composite material, specific capacity ≥1260mAh / g) are mixed at a mass ratio of 80:20.

[0226] Example 13 group

[0227] This set of embodiments is based on Embodiment 1, except that the compaction density of the positive electrode sheet is changed. Specifically:

[0228] Example 13a: The compaction density of the positive electrode sheet is 3.3 g / cm³. 3 ;

[0229] In Example 13b, the compaction density of the positive electrode sheet was 3.6 g / cm³. 3 ;

[0230] In Example 13c, the compaction density of the positive electrode sheet was 3.25 g / cm³. 3 ;

[0231] In Example 13d, the compaction density of the positive electrode was 3.7 g / cm³. 3 .

[0232] Example 14 group

[0233] This set of embodiments is based on Embodiment 1, except that the first positive electrode active material and the second positive electrode active material are changed (to verify the effect of changing 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), as shown in Table 1.

[0234] Example 15 group

[0235] This set of embodiments is based on Embodiment 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.

[0236] Example 16 group

[0237] This set of embodiments is based on Embodiment 1, except that the first positive electrode active material and the second positive electrode active material (verification (X)) are changed. 104 -X 003 ) / (T DSC ×I 003 / I 104 The impact of the changes is shown in Table 1.

[0238] Example 17 group

[0239] This set of embodiments is based on Embodiment 1, except that the negative electrode active material is changed. Specifically:

[0240] Example 17a: Artificial graphite (median particle size Dv50 = 14.484 μm and specific surface area 1.0134 m²) was used in the negative electrode active material. 2 The / g) was replaced with the same mass of artificial graphite (median particle size Dv50 = 13.674 μm and specific surface area 1.138 m²). 2 / g);

[0241] In Example 17b, the silicon-silicon oxide-silicon suboxide composite material (specific capacity ≥ 1260 mAh / g) in the negative electrode active material was replaced with the same mass of silicon-carbon composite material (specific capacity ≥ 1750 mAh / g).

[0242] Comparative Example 1

[0243] The procedure 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.

[0244] Comparative Example 2

[0245] The procedure 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.

[0246] Comparative Example 3

[0247] The procedure was carried out in accordance with Example 1, except that the second positive electrode active material was changed, as detailed in Table 1.

[0248] Table 1

[0249]

[0250]

[0251] Note: In Table 1, " / " indicates no data.

[0252] Test Case II

[0253] (1) Volumetric particle size test

[0254] The positive electrode sheets prepared in the examples and comparative examples were subjected to volumetric particle size testing, and the results are recorded in Table 2.

[0255] (2) XRD test

[0256] The positive electrode sheets prepared in the examples and comparative examples were subjected to XRD tests, and the results are recorded in Table 2.

[0257] (3) DSC test

[0258] The positive electrode sheets prepared in the examples and comparative examples were subjected to DSC testing, and the results are recorded in Table 2.

[0259] Table 2

[0260]

[0261]

[0262] Test Case III

[0263] The batteries prepared in the examples and comparative examples were tested using an Arbin BT2000 battery tester. The voltage range was set to 4.25V-2.5V. The test results are recorded in Table 3. The specific test methods are as follows:

[0264] 45℃ Cyclic Test: In a constant temperature environment of 45℃: 1. Let stand for 30 minutes; 2. Discharge at 1C constant current to the lower limit voltage; 3. Charge at 1.5C constant current and constant voltage to the upper limit voltage, with a cutoff current of 0.05C; 4. Discharge at 1C constant current to the lower limit voltage; 5. Repeat steps 3-4 to perform the cyclic test, and record the number of cycles to 80% SOH (SOH is the battery health status, which can be used to evaluate the health of the battery, i.e., the percentage of current capacity to factory capacity).

[0265] 45℃ Cyclic DCIR Test: 1. Rest for 30 min; 2. Charge at 1C constant current and constant voltage to the upper limit voltage, cutoff current 0.05C; 3. Discharge at 1C constant current to the lower limit voltage, record 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. Rest for 30 min; 7. Discharge at 3C for 10 s; record DCIR data, DCIR growth rate = (End DCIR - Initial DCIR) / Initial DCIR * 100%;

[0266] -10℃ Cyclic Test: In a constant temperature environment of -10℃: 1. Let 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 cutoff current of 0.05C; 4. Discharge at a constant current of 0.33C to the lower limit voltage; 5. Repeat steps 3-4 for cyclic testing.

[0267] Table 3

[0268] Number of cycles at 45℃ 45℃ Cyclic DCIR Growth Rate / % Capacity retention rate (%) after 100 cycles at -10℃ Example 1 524 22.63 97.68 Example 2 522 22.97 97.56 Example 3 519 23.31 97.47 Example 4a 450 30.82 91.91 Example 4b 514 40.67 89.26 Example 5a 518 24.36 96.98 Example 5b 516 24.28 96.04 Example 5c 510 25.32 95.97 Example 5d 508 25.58 95.92 Example 6a 498 25.91 95.82 Example 6b 492 25.96 95.86 Example 6c 486 26.37 94.99 Example 6d 483 26.39 94.93 Example 7a 487 26.09 94.95 Example 7b 482 25.37 94.31 Example 7c 497 23.29 95.88 Example 8 486 26.99 94.08 Example 9a 479 26.66 95.67 Example 9b 476 27.65 96.21 Example 10a 468 28.01 95.89 Example 10b 460 28.24 96.77 Example 11a 452 28.47 93.21 Example 11b 461 27.26 94.29 Example 12 500 26.29 96.77 Example 13a 554 23.26 98.25 Example 13b 520 22.43 97.25 Example 13c 562 23.2 98.3 Example 13d 508 26.32 95.44 Example 14a 1146 18.26 99.96 Example 14b 726 20.37 98.47 Example 15a 460 27.33 94.18 Example 15b 458 27.54 94.26 Example 15c 459 27.92 93.18 Example 16a 724 25.16 97.05 Example 16b 450 29.19 93.44 Example 17a 521 22.16 97.33 Example 17b 592 26.32 97.42 Comparative Example 1 320 60.89 40.25 Comparative Example 2 243 58.24 88.25 Comparative Example 3 430 32.85 90.06

[0269] As can be seen from Table 3, compared with Comparative Example 1 and Comparative Example 2, the Examples exhibit superior kinetic performance, lower internal resistance, and excellent cycle performance because the Examples use 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 voids formed by the second active material, so that the positive electrode sheet has excellent structural stability).

[0270] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A positive electrode plate, characterized in that, The positive electrode sheet includes a positive electrode active material, and 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, and the second positive electrode active material includes polycrystalline particles; 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, and 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; 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 element independently includes at least one of Sr, Y, Mg, Mo, Zr, and Ti; element A' 1 and element A' 2 All include W, Al, and B; element A' 1 In the mixture, the mass ratio of elements Al, W, and B is (0.9-5):(1-6):1, and the mass ratio of element A' is (0.9-5):(1-6):

1. 2 In this composition, the mass ratio of elements Al, W, and B is (1-3):(1-4):1; ElementA 1 The content of element A in the first positive electrode active material is m1. 2 The content of m3 in the second positive electrode active material, element A' 1 The content of element A' in the first positive electrode active material is m2. 2 The content of the second positive electrode active material is m4, which satisfies m2≤m4; m2 is 1000ppm-3000ppm, m4 is 3000ppm-4300ppm, m1+m2 is 2000ppm-10000ppm, and m3+m4 is 3500ppm-10000ppm. Based on the total weight of the positive electrode active materials, the content of the first positive electrode active material is 10-50% by weight, and the content of the second positive electrode active material is 50-90% by weight. 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, 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.

2. The positive electrode according to claim 1, wherein, m1 and m2 satisfy 4000ppm≤m1+m2≤7000ppm.

3. The positive electrode according to claim 1 or 2, wherein, 1≤m4 / m2≤4.

3.

4. The positive electrode sheet according to claim 3, wherein, 1≤m4 / m2≤2; And / or, m2 is 1500ppm-2500ppm.

5. The positive electrode according to claim 1 or 2, wherein, ElementA' 1 In this mixture, the mass ratio of elements Al, W, and B is (1-2):(1.2-4):1; And / or, element A' 2 In this mixture, the mass ratio of elements Al, W and B is (1-1.5):(1-2):

1.

6. The positive electrode according to claim 1 or 2, wherein, The first positive electrode active material fills the gaps between the second positive electrode active materials.

7. The positive electrode according to claim 1 or 2, wherein, Dv 1 10 <Dv 2 10; And / or, Dv 1 50 <Dv 2 50; And / or, Dv 1 90 <Dv 2 90.

8. The positive electrode according to claim 1 or 2, wherein, 0.8≤a1<1； And / or, 0.8≤a2<1.

9. The positive electrode according to claim 1 or 2, wherein, The long axis of the first positive electrode active material is 0.5 μm-3.5 μm; And / or, the long axis of the second positive electrode active material is 1μm-15μm; And / or, the compaction density of the positive electrode is 3 mg / cm³. 3 -4mg / cm 3 .

10. The positive electrode according to claim 9, wherein, The compaction density of the positive electrode is 3.3 mg / cm³. 3 - 3.6mg / cm 3 .

11. The positive electrode according to claim 1 or 2, wherein, The positive electrode is subjected to volumetric particle size testing. The test curve has at least two characteristic peaks. The particle size classification corresponding to the peak value of the first characteristic peak is P1, and the particle size classification corresponding to the peak value of the second characteristic peak is P2, satisfying 2μm≤P2-P1≤10μm.

12. The positive electrode according to claim 11, wherein, 1μm≤P1≤7μm; And / or, 5μm≤P2≤15μm.

13. The positive electrode according to claim 1 or 2, wherein, The XRD diffraction pattern of the positive electrode shows peaks on the 003 and 104 crystal planes, and the angle value corresponding to the peak 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 peak is X. 104 The ratio of the peak intensity of the 003 crystal plane peak to the peak intensity of the 104 crystal plane peak is I. 003 / I 104 Satisfying X 003 For 15°-23°, X 104 For 43°-45°, I 003 / I 104 Numbers 1-8; And / or, in the DSC spectrum of the positive electrode, the temperature T corresponding to the peak intensity position. DSC The temperature range is 200℃-250℃.

14. The positive electrode according to claim 1 or 2, wherein, The XRD diffraction pattern of the positive electrode shows peaks on the 003 and 104 crystal planes, and the angle value corresponding to the peak 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 peak is X. 104 The ratio of the peak intensity of the 003 crystal plane peak to the peak intensity of the 104 crystal plane peak is I. 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 Satisfying 0.01 ≤ (X) 104 -X 003 ) / (T DSC ×I 003 / I 104 ) ≤ 0.

15.

15. The positive electrode according to claim 14, wherein, X 003 X 104 T DSC and I 003 / I 104 Satisfying 0.02≤ (X) 104 -X 003 ) / (T DSC ×I 003 / I 104 ) ≤ 0.

06.

16. A battery, characterized in that, The battery comprises the positive electrode sheet according to any one of claims 1-15.

17. The battery according to claim 16, wherein, The battery further includes a negative electrode sheet; the negative electrode sheet includes a negative current collector and a negative active material layer located on at least one side surface of the negative current collector; the negative active material layer includes a negative active material, which includes at least one of carbon-based materials and silicon-based materials.

18. The battery according to claim 17, wherein, The carbon-based material includes at least one of natural graphite, artificial graphite, mesophase carbon microsphere graphite, soft carbon, and hard carbon. And / or, the silicon-based material includes at least one of silicon, silicon oxide, silicon carbon, and silicon alloys.

19. The battery according to claim 17, 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 m². 2 / g-3m 2 / g.

20. The battery according to claim 17, wherein, Based on the total weight of the negative electrode active material, the content c of the silicon-based material is 0%. <c≤30%; And / or, the negative electrode current collector further includes a carbon layer; And / or, the thickness of the carbon layer is 0-1.5 μm.

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