Positive electrode material, positive electrode plate, lithium ion battery and electric equipment

Abstract

The invention relates to a positive electrode material, a positive electrode plate, a lithium ion battery and electric equipment, the positive electrode material comprises an active material and a carbon material layer coating the active material, and the positive electrode material satisfies 40 < WC * IG / Iv < 120. The positive electrode material disclosed by the invention has a good carbon coating effect, the conductivity of the material and the slurry processing performance can be enhanced, and when the positive electrode material is used in the lithium ion battery, the polarization of the battery can be reduced, the rate capability can be improved, the impedance of the battery can be reduced, and the battery has excellent rapid charging and discharging capability.

Description

Technical Field

[0001] The present disclosure relates to a positive electrode material, a positive electrode sheet, a lithium-ion battery and an electrical device. Background Art

[0002] Extensive research indicates that the performance of cathode active materials is a key factor in determining the energy density, cycle life, and safety of lithium-ion batteries. Furthermore, cathode active materials contribute significantly to the production cost of lithium-ion batteries. Therefore, developing high-performance, low-cost cathode active materials is a key focus of current lithium-ion battery research. Among these, lithium iron phosphate (LiFePO4) boasts abundant raw material resources, environmental friendliness, and high safety, leading to its widespread commercial application.

[0003] The theoretical capacity of LiFePO4 is 170 mAh / g. Early studies have shown that the actual capacity can only reach about 60% of this, primarily due to its poor conductivity. As current density increases, the specific capacity decreases rapidly. To withstand high current charge and discharge, its electronic conductivity needs to be improved. Carbon coating is currently the primary research method for improving the conductivity of positive electrode active materials and is widely used in industry.

[0004] The coating effect of existing carbon-coated positive electrode materials is unsatisfactory, resulting in insignificant improvement in the electronic and ionic conductivity of the materials. Furthermore, due to the need for economic efficiency and production capacity, the preparation of positive electrode sheets generally pursues positive electrode slurries with higher solid content and lower viscosity. If the carbon coating effect is poor, excessive free carbon that is not tightly coated on the surface of the active material will significantly increase the difficulty of slurry preparation, resulting in increased slurry viscosity and poor stability, making it difficult to meet actual needs. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a positive electrode material, a positive electrode plate, a lithium-ion battery and an electrical device to improve the conductivity and slurry processing performance of the carbon-coated positive electrode material.

[0006] In order to achieve the above-mentioned object, the present disclosure provides a positive electrode material in the first aspect, wherein the positive electrode material comprises an active material and a carbon material layer covering the active material, wherein the positive electrode material satisfies 40<W C ×I G / I ν <120, where W C represents the carbon content of the positive electrode material, I G Represents the peak area of the G peak in the Raman spectrum of the positive electrode material, I ν Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode material.

[0007] Optionally, the positive electrode material satisfies 50<WC ×I G / I ν <100.

[0008] Optionally, based on the total weight of the positive electrode material, the carbon content W of the positive electrode material is C 0.8~3.0% by weight.

[0009] Optionally, the positive electrode material I G with I ν The ratio is 30~80.

[0010] Optionally, the general formula of the active material is LiFe 1-x M x PO4, wherein 0≤x<0.5, M is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti; The wave number range of the G peak is 1500~1700 cm -1 ; The symmetrical stretching vibration peak of the active material is PO4 3- The symmetrical stretching vibration peaks are in the range of 940–960 cm -1 .

[0011] Optionally, the carbon material layer is formed by a carbon source, and the carbon source is one or more selected from glucose, ethylene glycol, polyethylene glycol, sucrose, white sugar, starch, cellulose, phenolic resin, citric acid, glycine, ethylenediaminetetraacetic acid, agar and vitamin C.

[0012] Optionally, the Raman spectroscopy detection conditions of the cathode material include: exposure time 30s, laser intensity 1-5%, and test range 500-2000cm -1 . .

[0013] In a second aspect of the present disclosure, a positive electrode sheet is provided, comprising a positive electrode current collector and a positive electrode membrane disposed on at least one surface of the positive electrode current collector, wherein the positive electrode membrane comprises the positive electrode material described in the first aspect of the present disclosure.

[0014] In a third aspect of the present disclosure, a positive electrode plate is provided, wherein the positive electrode plate satisfies 40<W C ’ ×I G ’ / I ν ’ <120, where W C ’ Represents the carbon content of the positive electrode sheet, I G ’ Represents the peak area of the G peak in the Raman spectrum of the positive electrode, Iν ’ Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode.

[0015] In a fourth aspect of the present disclosure, a lithium-ion battery is provided, comprising the positive electrode sheet described in the second aspect or the third aspect of the present disclosure.

[0016] In a fifth aspect of the present disclosure, an electrical device is provided, comprising the lithium-ion battery described in the fourth aspect of the present disclosure.

[0017] Through the above technical solution, the positive electrode material disclosed in the present invention has a good carbon coating effect, which can enhance the conductive properties and slurry processing performance of the material. When used in lithium-ion batteries, it is beneficial to reduce the polarization of the battery, improve the rate performance, and reduce the battery impedance, so that the battery has excellent fast charging and discharging capabilities.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 This is a Raman spectrum of the positive electrode material of Example 1. DETAILED DESCRIPTION

[0020] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0021] In a first aspect of the present disclosure, a positive electrode material is provided, wherein the positive electrode material comprises an active material and a carbon material layer covering the active material, wherein the positive electrode material satisfies 40<W C ×I G / I ν <120, where W C represents the carbon content of the positive electrode material, I G Represents the peak area of the G peak in the Raman spectrum of the positive electrode material, I ν Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode material.

[0022] According to the present disclosure, in Raman spectroscopy, the G peak (Graphite peak) refers to a characteristic peak caused by the in-plane vibration of sp² hybridized carbon atoms in carbon materials (i.e., the stretching vibration of C-C bonds), and the wave number range of the G peak can be 1500-1700 cm -1The symmetric stretching vibration peak of the active material refers to the molecular or ionic groups (such as PO4 3- VO4 3- The characteristic peaks are caused by the symmetrical vibrations between the central atom and the surrounding coordinated atoms in the active material (e.g., etc.), and their wavenumber range can be determined according to the molecules or ionic groups contained in the active material. The Raman spectrum of the positive electrode material can be detected using commonly used equipment in the field under detection conditions familiar to those skilled in the art. For example, the Raman spectrum detection conditions of the positive electrode material may include: an exposure time of 30 seconds, a laser intensity of 1-5% (assuming the sample is not burned), and a test range of 500-2000 cm -1 The carbon content is calculated based on the total weight of the positive electrode material and can be obtained by testing according to the standard method GB / T 20123-2006.

[0023] In related technologies, the effectiveness of carbon-coated positive electrode materials is usually evaluated by measuring the amount of carbon residue in the material. However, this method cannot provide detailed information about the distribution of carbon on the surface of the positive electrode material. At present, the commonly used method to observe the distribution of carbon on the surface of the active material is to use a transmission electron microscope, but this method is limited by the resolution and can only observe nanoscale details, and may lead to unrepresentative results for large-scale samples of powder materials. Another common evaluation method is to test the conductivity and battery capacity performance after preparing the battery. However, this method requires complex experimental steps, is costly, and takes a long time.

[0024] The inventors of the present disclosure have found that under appropriate carbon content conditions, the ratio of the peak area of the G peak in the Raman spectrum of the positive electrode material to the symmetric stretching vibration peak of the active material can reflect the coating degree and quality of the carbon material. By controlling the range of the product of the two, the coating uniformity and stability of the carbon material layer can be achieved. The positive electrode material of the present disclosure meets 40<W C ×I G / I ν <120, showing a good carbon coating effect. On the one hand, it can form a conductive network, reduce the polarization of the battery, and improve the charge transfer efficiency and power density of the battery; on the other hand, it can effectively improve the dispersibility and viscosity of the positive electrode slurry, making the positive electrode slurry easier to process and shape, which is conducive to the preparation of high-quality positive electrode sheets and lithium-ion batteries.

[0025] In a preferred embodiment, the positive electrode material satisfies 50<W C ×I G / I ν <100, at this time, the positive electrode material has a further improved carbon coating effect.

[0026] In a specific embodiment, based on the total weight of the positive electrode material, the carbon content of the positive electrode material is W C The I of the positive electrode material may be 0.8 to 3.0 wt %, preferably 1.0 to 2.5 wt %. G with I ν The ratio (i.e. I G / I ν ) can be 30 to 80, preferably 40 to 80. When the carbon content and / or I G with I ν When the ratio is controlled within the preferred range, it is beneficial to further improve the conductivity and slurry processing performance of the positive electrode material.

[0027] In a specific embodiment, the active material can be a phosphate system positive electrode material. Specifically, the general formula of the active material is LiFe 1-x M x PO4, wherein 0≤x<0.5, M is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti. For example, the active material may be LiFePO4, LiFe 0.95 Mn 0.05 PO4、LiFe 0.6 Mn 0.4 PO4、LiFe 0.7 Mn 0.3 PO4, etc. At this time, the symmetrical stretching vibration peak of the active material is PO4 3- The symmetrical stretching vibration peaks are in the range of 940–960 cm -1 The anionic groups in the phosphate system positive electrode material can also be replaced by P elements and / or PO4 by means of trace doping. 3- , such as: S, SO4 2- , B, BO3 3- , the substitution amount can be 0~5% by weight.

[0028] The carbon material layer is formed by a carbon source, and the carbon source can be one or more selected from glucose, ethylene glycol, polyethylene glycol, sucrose, starch, white sugar, cellulose, phenolic resin, citric acid, glycine, ethylenediaminetetraacetic acid, agar and vitamin C.

[0029] In the positive electrode material, the active material can be formed into a spherical and / or quasi-spherical core, and the carbon material layer is coated on the surface of the spherical and / or quasi-spherical core. The carbon material layer can have one or more layers, and the carbon material can be formed into particles or a continuous film. The specific size of the positive electrode material is not particularly limited. For example, the particle size of the active material core can be 0.01 to 20 μm, and the thickness of the carbon material layer can be 0.5 to 30 nm.

[0030] The present disclosure has no particular limitation on the preparation method of the positive electrode material, and the positive electrode material can be prepared by methods in the prior art, such as high-temperature solid-phase method, liquid-phase method, autothermal evaporation method, sol-gel method, multi-step sintering method, multi-step coating method, etc.

[0031] In one specific embodiment, the method for preparing the positive electrode material includes: (1) The iron source, lithium source, phosphorus source, and M source are adjusted in proportion so that the molar ratio of lithium, iron, phosphorus, and M can be (0.9-1.3): (1-1.3): (0.9-1.2): (0-1.0). Preferably, the molar ratio of lithium, iron, phosphorus, and M is (0.9-1.1): (1-1.1): (0.96-1): (0-0.7), and the mass of the carbon source can account for 0.5-30% of the sum of the mass of the lithium source, iron source, and phosphorus source. Exemplarily, the mass proportion is 0.8%, 1%, 1.5%, 2%, 5%, 8%, 10%, 12%, 15%, or 18%, 22%, 25%, 28%, etc. Preferably, the mass of the carbon source accounts for 5-20% of the sum of the mass of the lithium source, iron source, and phosphorus source, and more preferably 8-18%.

[0032] (2) Mix the iron source, lithium source, phosphorus source, M source, and carbon source in an aqueous or organic solvent and ball mill them at a solid content of 35-65%. After the ball milling, the material is dried to a solvent content of <5%, and then sintered at 400-900°C to obtain the positive electrode material. The carbon source can be added in one step or in multiple steps, such as before sand milling or during sintering. The sintering can be performed once or multiple times.

[0033] Wherein, the iron source can be one or more selected from FeSO4, FePO4, FeCl2, FeC2O4, Fe3O4, Fe2O3, FeCO3; the lithium source can be one or more selected from Li2CO3, LiOH·H2O, LiH2PO4, Li2HPO4, Li3PO4, Li2NH4PO4, Li(NH4)2PO4, LiPO4, Li4P2O7; the phosphorus source can be one or more selected from FePO4, NH4H2PO4, (NH4)2HPO4, H3 PO4, LiH2PO4, Li2HPO4, Li3PO4, Li2NH4PO4, Li(NH4)2PO4 or more; the M source may be a simple substance and / or compound of one or more elements selected from Cu, Mn, Cr, Zn, Pb, Ca, Co, Ni, Sr, Nb, Ti, and V; the carbon source may be selected from but not limited to glucose, ethylene glycol, polyethylene glycol, sucrose, white sugar, starch, cellulose, phenolic resin, citric acid, glycine, ethylenediaminetetraacetic acid, agar, and one or more of vitamin C.

[0034] The positive electrode material disclosed in the present invention not only meets the requirements of high capacity, but also has a reasonable specific surface energy, excellent energy density, rate performance, impedance performance and excellent slurry processing performance. The positive electrode sheet prepared using this positive electrode material exhibits excellent electrochemical performance.

[0035] In a second aspect of the present disclosure, a positive electrode sheet is provided, comprising a positive electrode current collector and a positive electrode membrane disposed on at least one surface of the positive electrode current collector, wherein the positive electrode membrane comprises the positive electrode material described in the first aspect of the present disclosure.

[0036] In a third aspect of the present disclosure, a positive electrode plate is provided, wherein the positive electrode plate satisfies 40<W C ’ ×I G ’ / I ν ’ <120, where W C ’ Represents the carbon content of the positive electrode sheet, I G ’ Represents the peak area of the G peak in the Raman spectrum of the positive electrode, I ν ’ Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode plate. The positive electrode plate has the characteristics and benefits of the positive electrode material described in the first aspect of the present disclosure. The meanings of the relevant parameters are as described above and will not be elaborated here.

[0037] There is no particular limitation on the method for preparing the positive electrode sheet described in the second aspect or the third aspect of the present disclosure, and processes and equipment well known in the art may be used.

[0038] In a fourth aspect of the present disclosure, a lithium-ion battery is provided, characterized by comprising the positive electrode sheet described in the second or third aspect of the present disclosure. The specific structure of the lithium-ion battery is not particularly limited, and the battery may include other structures commonly used in the art, such as a negative electrode sheet, a separator, and an electrolyte.

[0039] By adopting the positive electrode material disclosed in the present invention, the performance of lithium-ion batteries has been significantly improved in all aspects. It is not only suitable for fields such as electric vehicles and portable devices that have high requirements for high energy density and fast charging and discharging, but also for large-scale energy storage systems, showing broad application prospects and market potential.

[0040] In a fifth aspect of the present disclosure, an electrical device is provided, comprising the lithium-ion battery described in the fourth aspect of the present disclosure. The electrical device may be, for example, a power battery module, an energy storage cabinet, or the like.

[0041] The present disclosure is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are not intended to limit the present disclosure.

[0042] The raw materials and reagents used in the examples and comparative examples are all commercially available products.

[0043] In this embodiment, the carbon content is tested by burning the positive electrode material in a high-frequency induction furnace and then measuring the carbon content using infrared absorption. The specific testing process is based on the standard GB / T 20123-2006, "Determination of Total Carbon and Sulfur Content of Iron and Steel - Infrared Absorption Method after Combustion in a High-Frequency Induction Furnace (Conventional Method)." If the material is on the electrode, a portion of the electrode is cut and soaked in acetone for half an hour, then the dressing is scraped off. The dressing is then baked in an 80°C oven for 12 hours until dry before testing.

[0044] The Raman spectroscopy test method is as follows: the equipment used is a Renishaw Qontor Raman spectrometer, the laser intensity is 1~5% (be careful not to burn the sample to prevent the occurrence of stray peaks affecting the results), and the test range is 500-2000cm -1 ; Use the wire software tool, click the Cosmic ray removal button to remove the background noise peak, use Analysis-curve fit to perform peak fitting, and obtain the G peak and PO4 3- The peak area corresponding to the peak I G and I ν .

[0045] Example 1 Prepare the cathode material as follows: 1) A lithium source, an iron source, and a phosphorus source are preliminarily mixed according to a molar ratio of Li:Fe:P:M=1.02:1:1:0, wherein the lithium source is lithium carbonate, and iron phosphate is the iron source and phosphorus source; then a carbon source (specifically polyethylene glycol + white sugar) is added thereto, and the added mass of the carbon source is 10wt.% of the sum of the mass of the lithium source, the iron source, and the phosphorus source; 2) Place the lithium carbonate, iron phosphate, and sugar mixture in a ball mill and add water as a solvent. After ball milling, the resulting precursor has a D50 particle size of 200-600 nm. 3) The ball-milled precursor is spray-dried and granulated to obtain granulated powder with a particle size range of 10-80 μm; 4) heating the granulated powder to 700-800°C at a heating rate of 0.5-5°C / min under a nitrogen atmosphere, sintering for 10-24 hours, and cooling the material to a temperature of <80°C to obtain a primary sintered material; 5) After mixing the primary sintered materials, a secondary sintering is performed. During the secondary sintering, a polyethylene glycol solution is used for CVD coating. The secondary sintering heating rate is 0.5-5°C / min, and the temperature is raised to 600-800°C. The temperature is kept at this temperature for 10-24 hours, and the materials are cooled to a temperature of less than 80°C to obtain the secondary sintered materials. 6) The secondary fired material is gas-crushed to obtain lithium iron phosphate positive electrode material.

[0046] In the positive electrode material prepared in this embodiment, the active material is LiFePO4, the average particle size of the active material core is 300-350 nm, and the thickness of the carbon material layer is 3-5 nm. The Raman spectrum of the positive electrode material is as follows: Figure 1 As shown, it can be seen that it has a -1 The G peak at 951 cm -1 PO4 3- Characteristic peak, W C , I G / I ν The data are listed in Table 1.

[0047] Examples 2 to 10 The positive electrode material was prepared according to the method of Example 1, except that at least one variable among the Li / Fe / P / M element ratio, carbon source type, carbon source addition amount, carbon source addition method, and sanding particle size was adjusted. C , I G / I ν The data are listed in Table 1.

[0048] Comparative Examples 1 to 7 The positive electrode material was prepared according to the method of Example 1, except that the step 5) was omitted. The W C , I G / Iν The data are listed in Table 1.

[0049] Examples 11 to 13 The positive electrode sheet was prepared according to the following steps: the positive electrode material was mixed with a binder (specifically polyvinylidene fluoride, PVDF) and a conductive agent in a mass ratio of 90:5:5, and an appropriate amount of N-methyl ketone pyrrole (NMP) was added to the other materials and mixed evenly to obtain a positive electrode slurry; the positive electrode slurry was coated on one side of a carbon-coated aluminum foil and baked to dry. The W of the obtained positive electrode sheet was C , I G / I ν The data are listed in Table 1.

[0050] Comparative Examples 8-9 The positive electrode sheet was prepared according to the method of Example 11. The W C , I G / I ν The data are listed in Table 1.

[0051] Table 1

[0052] Test Case The positive electrode materials or pole pieces of the examples and comparative examples were prepared into lithium-ion batteries by the following method: the positive electrode material was mixed with a binder (specifically polyvinylidene fluoride, PVDF) and a conductive agent in a mass ratio of 90:5:5, and an appropriate amount of N-methyl ketone pyrrole (NMP) was added to the other materials, and the mixture was uniformly mixed to obtain a positive electrode slurry; the positive electrode slurry was coated on both sides of a carbon-coated aluminum foil with a surface density of 300-600 g / m 2 , the pole piece is rolled after drying, and the compaction after rolling is 2.4~2.8 g / cm 3 40-50Ah batteries were prepared using the graphite electrode as the negative electrode, a PP or PE separator, and a 1.0 mol / L LiPF₆ solution of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a 1:1 (volume ratio) as the electrolyte. Rate and impedance tests were then conducted, and the positive electrode material slurry viscosity was tested. The results are shown in Table 2.

[0053] The rate performance test method is as follows: at 25°C, the lithium-ion battery is fully charged at a rate of 1 / 3C and fully discharged at a rate of 1 / 3C for three cycles, and the actual discharge capacity at the third time is recorded as the initial capacity E0; the lithium-ion battery is then fully charged at a rate of 1 / 3C and fully discharged at a rate of 5C for three cycles, and the third discharge capacity is taken as the rate capacity E1; the rate performance is evaluated by E1 / E0. For each batch of batteries, more than 2 batteries are selected for testing, and the test average of the two batteries with a range of less than 2% is taken as the final result. Among them, the rate performance level is defined as follows: the target value of the rate performance is 95%. When the actual test value is less than 95% of the target value, the performance is considered to be at level C; when the actual test value is greater than or equal to 95% of the target value and less than 105% of the target value, the battery performance is considered to be at level B; when the actual test value is greater than or equal to 105% of the target value, the battery performance is considered to be at level A.

[0054] The impedance test method uses DCIR to assess battery impedance. At 25°C, the lithium-ion battery is fully charged at a 1 / 3C rate and fully discharged at a 1C rate for three cycles. The actual discharge capacity at the third cycle is recorded as the initial capacity (C0). After fully charging the lithium-ion battery at 1 / 3C, it is discharged at 1C0 for 24 minutes to 60% SOC. The battery is then left at room temperature for 2 hours, and the end-of-hold voltage (V0) is recorded. It is then charged at 3C for 30 seconds, and the cut-off voltage (V1) is recorded. DCIR = (V1-V0) / 3C. More than two batteries from each batch are tested, and the average of the two batteries with a range of less than 2% is used as the final result. Among them, the impedance performance level is defined as: the target value of the impedance performance is 2.5 mΩ. When the actual test value is less than 95% of the target value, the performance is considered to be at level A; when the actual test value is greater than or equal to 95% of the target value and less than 105% of the target value, the battery performance is considered to be at level B; when the actual test value is greater than or equal to 105% of the target value, the battery performance is considered to be at level C.

[0055] The slurry viscosity test method involves mixing the cathode material, conductive agent carbon black, binder polyvinylidene fluoride (PVDF), and solvent NMP in a weight ratio of 90:5:5:50. The mixture is stirred in a blender until the mixture is homogeneous to obtain the cathode slurry. The slurry viscosity is then measured using a rheometer, with the viscosity reading corresponding to 50 s-1 being taken. The slurry viscosity level is defined as follows: when the target viscosity is 3000 mPa·s and the actual viscosity is greater than or equal to 95% and less than 105% of the target viscosity, the slurry viscosity is considered moderate, classified as Level A; when the actual viscosity is greater than or equal to 105% and less than 120% of the target viscosity, the actual viscosity is considered high, classified as Level B; and when the actual viscosity is greater than or equal to 120% of the target viscosity, the actual viscosity is considered very high, classified as Level C. Table 2

[0056] As can be seen from Table 2, the positive electrode materials or pole pieces of the embodiments have excellent rate performance levels, impedance performance levels and slurry viscosity levels.

[0057] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0058] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0059] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A positive electrode material, characterized in that The positive electrode material includes an active material and a carbon material layer covering the active material. The positive electrode material satisfies 40<W C ×I G / I ν <120, where W C represents the carbon content of the positive electrode material, I G Represents the peak area of the G peak in the Raman spectrum of the positive electrode material, I ν Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode material.

2. The positive electrode material according to claim 1, wherein The positive electrode material satisfies 50<W C ×I G / I ν <100.

3. The positive electrode material according to claim 1, wherein Based on the total weight of the positive electrode material, the carbon content of the positive electrode material is W C 0.8~3.0% by weight.

4. The positive electrode material according to claim 1, wherein The positive electrode material I G with I ν The ratio is 30~80.

5. The positive electrode material according to claim 1, wherein The general formula of the active material is LiFe 1-x M x PO4, wherein 0≤x<0.5, M is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti; The wave number range of the G peak is 1500~1700 cm -1 ; The symmetrical stretching vibration peak of the active material is PO4 3- The symmetrical stretching vibration peaks are in the range of 940–960 cm -1 .

6. The positive electrode material according to claim 1, wherein The carbon material layer is formed by a carbon source, and the carbon source is one or more selected from glucose, ethylene glycol, polyethylene glycol, sucrose, white sugar, starch, cellulose, phenolic resin, citric acid, glycine, ethylenediaminetetraacetic acid, agar and vitamin C.

7. The positive electrode material according to claim 1, wherein The Raman spectroscopy detection conditions of the positive electrode material include: exposure time 30s, laser intensity 1-5%, and test range 500-2000cm -1 .

8. A positive electrode plate, characterized in that: The invention comprises a positive electrode current collector and a positive electrode membrane provided on at least one surface of the positive electrode current collector, wherein the positive electrode membrane comprises the positive electrode material according to any one of claims 1 to 7.

9. A positive electrode plate, characterized in that: The positive electrode plate satisfies 40<W C ’ ×I G ’ / I ν ’ <120, where W C ’ Represents the carbon content of the positive electrode sheet, I G ’ Represents the peak area of the G peak in the Raman spectrum of the positive electrode, I ν ’ Represents the peak area of the symmetric stretching vibration peak of the active material in the Raman spectrum of the positive electrode.

10. A lithium ion battery, characterized in that: Including the positive electrode sheet according to claim 8 or 9.

11. An electrical device, characterized in that: Including the lithium ion battery according to claim 10.

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