Positive electrode material, lithium ion battery and electric device thereof

Abstract

The invention discloses a positive electrode material, a lithium ion battery and an electric device thereof, and relates to the technical field of lithium ion batteries. The positive electrode material comprises a positive electrode current collector and positive electrode slurry coated on the surface of the positive electrode current collector, and the raw material of the positive electrode slurry comprises a positive electrode active material; and the positive electrode active material comprises a LiNi < 0.6 > Co < 0.2 > Al < 0.1 > Mn < 0.1 > O < 2 > material of which the outer part is at least coated with LiWPO4. According to the lithium ion battery, the energy density exceeds 300 Wh / kg, the upper limit of the use voltage reaches 4.3-4.5 V, and the lithium ion battery has the characteristics of high energy density, good cycle performance, good safety performance, high manufacturing feasibility and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to positive electrode materials, lithium ion batteries and electrical devices thereof. Background Art

[0002] With the popularity of electric vehicles, people have higher requirements for the range and safety performance of electric vehicles. Batteries, as core components of electric vehicles, play an important role in range and safety performance. Therefore, the development of high-energy-density and high-safety batteries has become an industry trend.

[0003] In the existing technology, for example, the high energy density lithium ion power battery provided by Chinese patent application CN107819154A relates to a high energy density lithium ion power battery, the positive electrode of the battery is selected from LiNi x Co y Mn z Material or nickel-cobalt-aluminum ternary positive electrode material LiNi x Co y Al z O2, where 0.7≤x≤0.9, 0.05<y<0.15, x+y+z=1, and the negative electrode is made of silicon carbide or SiOx coated with a conductive carbon source. The energy density of the final single cell prepared reaches 280wh / kg, which improves the range of electric vehicles to a certain extent. The positive electrode material used in this battery has slightly poor battery cycle performance and thermal stability. The main reasons are: (1) The Ni content accounts for 0.7-0.9, which is a high-nickel positive electrode material; during the charge and discharge process, Ni 4+ and Ni 3+ 、Ni 2+ will constantly transform into each other; 2+ The volume and Li + Similarly, it will occupy Li during discharge. + (1) The position of cations in the lattice is mixed, and the increase in Ni content increases the probability of this phenomenon, resulting in poor battery cycle performance; (2) The higher the Ni content, the lower the starting temperature of the phase change of the material, and the greater the amount of oxygen released, which makes the thermal stability of the battery material worse and increases the risk of thermal runaway, ultimately leading to poor battery safety performance; (3) The higher the Ni content, the higher the total alkali content, which means that there are more lithium residues on the surface of the particles, which are very easy to absorb carbon dioxide and water in the air, and form lithium carbonate and lithium hydroxide layers on the surface of the particles, consuming Li in the material and causing capacity decay. Therefore, the higher the environmental moisture requirements during the battery production process, the higher the manufacturing cost; (4) The higher the Ni content, the more Li is consumed to generate lithium carbonate, which will hinder the diffusion of Li and affect battery performance. It is also easy to decompose and produce carbon dioxide at high potential, causing battery bulging and leakage; the generated lithium hydroxide will react with lithium hexafluorophosphate, consuming Li in the electrolyte+ Hydrofluoric acid is generated, which destroys the SEI film and corrodes the metal parts inside the battery, also causing battery leakage; (5) The silicon-carbon or silicon-oxygen negative electrode coated with a conductive carbon source will generate a large amount of bubbles during the homogenization process due to the reaction with water, and will also continuously generate gas during the coating process, resulting in the defect of foil leakage in the coating roll stock and leading to scrapping.

[0004] In some studies, reducing the content of Ni in the cathode material of lithium-ion batteries has been considered. For example, the high-voltage single-crystal ternary cathode material (medium-Ni high-voltage cathode material) provided by Chinese Patent Application CN115172719A reduces the Ni content (medium Ni content) and at the same time increases the upper limit voltage of use, thus ensuring the same capacity as the cathode material with a high Ni content. However, this patent does not conduct coating doping analysis, and it is impossible to predict the conductivity and thermal stability.

[0005] Therefore, how to prepare a lithium-ion battery that takes into account high energy density, good cycle performance and high safety performance is an urgent problem to be solved in the current industry. Summary of the Invention

[0006] In view of the above deficiencies of the prior art, the present invention provides a cathode material, a lithium-ion battery and an electrical device, which can solve the problem that energy density, cycle performance and safety performance cannot be taken into account at the same time, and are specifically realized through the following technologies.

[0007] A cathode material includes a cathode current collector and a cathode slurry coated on the surface of the cathode current collector, and the raw materials of the cathode slurry include cathode active materials; the cathode active materials include LiNi coated with lithium tungstate phosphate (LiWPO4) at least on the outside 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 material.

[0008] The cathode material provided by the present invention uses LiNi a Co b Al c Mn d O2 high-voltage cathode material (a + b + c + d = 1, for example, LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2) as the matrix. The Ni element can increase the capacity, the Co element can increase the electronic conductivity, and the Al element and the Mn element can stabilize the structure. The key technical point of this cathode material is that it also has LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1The outside of the O2 matrix is coated with lithium tungstophosphate (LiWPO4). The lithium tungstophosphate coating contains W and P elements, and the excess electrons in the outer layer of the atoms can enhance the binding with Li + and improve the conductivity of Li + . It can also effectively alleviate the reaction between the cathode material and the electrolyte, inhibit irreversible phase transformation and the dissolution of transition metals; the lithium tungstophosphate has good thermal stability, which relatively improves the thermal stability of the cathode material; the conductivity of the lithium tungstophosphate is relatively poor, which can increase the contact impedance when an internal short circuit occurs in the battery cell.

[0009] Preferably, the coating amount of LiWPO4 in the cathode active material is 0.1-1.0% of the total mass of the cathode active material.

[0010] Preferably, the preparation method of the LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 includes: sintering nickel-cobalt-manganese precursor Ni x Co y Mn z (OH)2, lithium carbonate Li2CO3, and Al(OH)3 at high temperature to obtain LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2; wherein the lithium carbonate is in excess by 5%-10%.

[0011] Preferably, the preparation method of the cathode active material includes: mixing LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2, ammonium tungstate, and ammonium phosphate in a mass ratio of 100:(0.1-2.0):(0.1-2.0), sintering, screening, and demagnetizing to obtain the finished product of the cathode active material.

[0012] Preferably, the sintering temperature in step S1 is 600-900 °C; the optimal is 800 °C.

[0013] Preferably, the sintering temperature in step S2 is 600-900 °C, and the optimal is 650 °C.

[0014] Most preferably, the mass percentage / dosage ratio of LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2, ammonium tungstate, and ammonium phosphate is 100:0.8:0.8.

[0015] Preferably, the raw materials of the dry powder of the positive electrode material are by weight percentage: 95-97.5% of positive electrode active material, 1.5-3.5% of positive electrode conductive agent, and 1-2% of positive electrode binder. The sum of the mass percentages of the three is 100%.

[0016] Preferably, the positive electrode conductive agent can be selected from at least one of conductive carbon black, carbon nanotubes, carbon fibers, and graphene.

[0017] Preferably, the positive electrode binder can be selected from polyvinylidene fluoride, polyimide, etc.

[0018] Preferably, the surface of the LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 material is also coated with an auxiliary material, and the auxiliary material is at least one of Al2O3, AlF3, and TiO2.

[0019] More preferably, the mass ratio of lithium phosphotungstate to the auxiliary material is 1:(0.5-2.0).

[0020] Further preferably, the auxiliary material is Al2O3, and the mass ratio of lithium phosphotungstate to the auxiliary material is 1:1.

[0021] It should be noted that in the positive electrode active material provided by the present invention, on the basis of coating lithium phosphotungstate on the surface of the LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 material, one or more other auxiliary materials can also be additionally coated, such as Al2O3, AlF3, TiO2, etc. Using the positive electrode material coated with these auxiliary materials, the finally prepared lithium-ion battery can also obtain the same or similar electrochemical performance and stability.

[0022] Preferably, the positive electrode current collector can be selected as an aluminum foil with a thickness of 10-14 μm.

[0023] Preferably, the double-sided surface density of the positive electrode material is 3-5 g / 100 cm 2 , and the compaction density is 3.40-3.65 g / cm 3 .

[0024] The present invention also uses the above positive electrode material as the preparation raw material of the positive electrode plate to prepare a high energy density lithium-ion battery.

[0025] The lithium-ion battery disclosed by the present invention also includes a negative electrode plate.

[0026] The lithium-ion battery also includes a separator, an electrolyte, and a packaging film.

[0027] Preferably, in the high-energy density lithium-ion battery provided by the present invention, the negative electrode sheet is made of a negative electrode material, and the negative electrode material includes a negative electrode current collector and a negative electrode paste coated on the surface of the negative electrode current collector. The negative electrode paste includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and a negative electrode thickener.

[0028] Preferably, the negative electrode paste has a dry powder mass fraction of: 93-97% of the negative electrode active material, 0.5-1.5% of the negative electrode conductive agent, 1.5-3.5% of the negative electrode binder, and 0.5-3% of the negative electrode thickener. The sum of the mass percentages of the four is 100%.

[0029] Preferably, the negative electrode conductive agent can be at least one of conductive carbon black, carbon nanotubes, carbon fibers, and graphene.

[0030] Preferably, the negative electrode binder can be styrene-butadiene rubber and / or polyacrylate.

[0031] Preferably, the negative electrode thickener is sodium carboxymethylcellulose, sodium alginate, etc.

[0032] In the high-energy density lithium-ion battery provided by the present invention, the material of the negative electrode sheet is silicon carbon / silicon oxide compound.

[0033] Preferably, the negative electrode current collector is a copper foil with a thickness of 5-8 μm; the double-sided areal density of the negative electrode material is 1.6-2.0 g / 100 cm 2 ; the tap density is 1.55-1.65 g / cm 3 .

[0034] Optionally, the separator can be a single-layer ceramic separator with a thickness of 8-14 μm.

[0035] Optionally, the electrolyte can use LiPF6 as the solute and at least one of EC, EMC, DEC, PC, and DMC as the solvent.

[0036] Optionally, the electrolyte also contains fluoroethylene carbonate, vinylene carbonate, biphenyl additives, etc. The electrolyte concentration is 0.5-2 mol / L.

[0037] Optionally, the battery can be encapsulated with an aluminum-plastic film, and the upper limit of the working voltage is in the range of 4.3V-4.5V.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. The present invention provides a cathode material for a high-energy density lithium-ion battery, and its core component, the cathode active material LiNi 0.6 Co 0.2 Al0.1 Mn 0.1 O2 significantly improves the electrochemical performance and thermal stability and extends the cycle life of lithium batteries by relatively reducing the amount of Ni used and coating LiWPO4 on the surface.

[0040] 2. The lithium-ion battery prepared with the cathode material provided by the present invention has an energy density exceeding 300 Wh / kg, a maximum operating voltage reaching 4.3 - 4.5 V, and the onset temperature and maximum temperature of battery thermal runaway are significantly higher than those of existing high-nickel cathode materials, indicating a great improvement in safety performance.

[0041] 3. The battery of the present invention has the characteristics of high energy density, good cycle performance, high safety performance, and broad industrialization prospects. Detailed Embodiments

[0042] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0043] It should be noted that, in addition to the specific technical solutions of the following examples and comparative examples, the positive electrode current collector can also be an aluminum foil with a thickness of 10 - 14 μm, and the double-sided areal density of the positive electrode material is 3 - 5 g / 100 cm 2 , and the tap density is 3.40 - 3.65 g / cm 3 . The coating amount of LiWPO4 in the positive electrode active material can be selected from 0.1 - 1.0%.

[0044] The negative electrode current collector can be a copper foil with a thickness of 5 - 8 μm, and the double-sided areal density of the negative electrode material is 1.6 - 2.0 g / 100 cm 2 ; the tap density is 1.55 - 1.65 g / cm 3 . By adopting the above optional technical solutions, compared with conventional high-nickel lithium batteries, the energy density, cycle life, and stability of lithium batteries can be significantly improved.

[0045] It should be noted that, in addition to the specific technical solutions of the following examples and comparative examples, other common materials such as carbon nanotubes, carbon fibers, and graphene can also be used as the positive electrode conductive agent. Similar to the positive electrode conductive agent, the negative electrode conductive agent can also be common materials such as carbon nanotubes, carbon fibers, and graphene.

[0046] It should be noted that, in addition to the specific technical solutions of the following examples and comparative examples, in the preparation method of the positive electrode active material:

[0047] Optionally, the sintering temperature in step (1) can also be selected from 600 - 900 °C, preferably 750 - 850 °C, and optimally 800 °C.

[0048] Optionally, the sintering temperature in step (2) can be selected from 600 - 900 °C, preferably 600 - 700 °C, and optimally 650 °C.

[0049] Optionally, in step (2), the amounts of LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2, ammonium tungstate, and ammonium phosphate can be selected within the range of 100:(0.1 - 2.0):(0.1 - 2.0).

[0050] It should be noted that in addition to the specific technical solutions of the following examples and comparative examples, the solvent of the electrolyte in the preparation method of the lithium-ion battery can be selected from conventional carbonates. In addition to fluoroethylene carbonate FEC, dimethyl carbonate DEC, ethyl methyl carbonate EMC, ethylene carbonate EC, etc. can also be used.

[0051] Example 1

[0052] In the positive electrode material, negative electrode material, and corresponding lithium-ion battery provided in this example, the positive electrode material used includes a positive electrode current collector and a positive electrode paste coated on the surface of the positive electrode current collector. The raw materials of the positive electrode paste are 97.5% of positive electrode active material, 1.5% of positive electrode conductive agent, and 1% of positive electrode binder according to the dry powder mass fraction. After roll pressing, the coated electrode is dried after coating. The coating amount of LiWPO4 in the positive electrode active material is 0.5% of the total mass of the positive electrode active material.

[0053] The preparation method of the positive electrode active material (i.e., LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2) coated with lithium phosphotungstate on the outside is as follows:

[0054] (1) Sinter Ni x Co y Mn z (OH)2, lithium carbonate Li2CO3, and Al(OH)3 at 800 °C to obtain LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2; where the lithium carbonate is in an excess of 5% - 10%;

[0055] (2) For LiNi 0.6 Co 0.2 Al 0.1 Mn0.1 O2 is mixed with ammonium tungstate and ammonium phosphate in a ratio of 100:0.8:0.8 and stirred evenly, then sintered at a temperature of 650 °C. After sintering, screening and demagnetization are carried out to obtain LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 cathode active material.

[0056] The preparation method of the cathode material is as follows: The cathode slurry is evenly coated on both the front and back sides of the cathode current collector, and then placed in a vacuum drying oven. It is baked and dried at 85 °C in a vacuum environment of -0.09 to -0.1 MPa to remove the solvent. Then it is rolled with a calender until the double-sided surface density is 4.0 g / 100 cm 2 , and the compaction density is 3.50 g / cm 3 , and then the whole is baked at 110 °C in a vacuum environment of -0.09 to -0.1 MPa to prepare.

[0057] The cathode current collector is made of 13-μm aluminum foil. The cathode slurry used is prepared by adding the cathode active material, the cathode conductive agent (carbon nanotubes), and the cathode binder (polyvinylidene fluoride, PVDF) in specific mass ratios according to each example or comparative example, and then stirring evenly with a solvent (N-methylpyrrolidone, NMP).

[0058] The anode material used includes an anode current collector and an anode slurry coated on the surface of the anode current collector. The raw materials of the anode slurry are in dry powder mass fractions of 96% anode active material, 1.0% conductive agent, 2.5% binder, 0.5% thickener, and silicon carbide / silicon oxide compound is used as the anode active material.

[0059] The preparation method of the anode material is as follows: The anode slurry is coated on both the front and back sides of the anode current collector, and then placed in a vacuum drying oven. It is baked and dried at 85 °C in a vacuum environment of -0.09 to -0.1 MPa to remove the solvent. Then it is rolled with a calender until the double-sided surface density of the anode is 1.80 g / 100 cm 2 ; the compaction density is 1.55 g / cm 3 , and then the whole is baked at 110 °C in a vacuum environment of -0.09 to -0.1 MPa to prepare; the anode current collector is made of 6-μm copper foil. The anode slurry used is prepared by adding the anode active material, the anode conductive agent (carbon nanotubes), the anode binder (polyacrylate), and the anode thickener (sodium carboxymethyl cellulose CMC) in specific mass ratios according to each example or comparative example, and then stirring evenly with a solvent (water).

[0060] The lithium-ion batteries prepared in this embodiment are all laminated in sequence with a positive electrode sheet, a separator, and a negative electrode sheet, and then encapsulated with an aluminum-plastic film. After drying, an electrolyte containing LiPF6 (concentration 1 mol / L, and the solvent is fluoroethylene carbonate FEC) is injected and sealed. Finally, the above-mentioned lithium-ion batteries after injection and encapsulation are formed and capacity-fractionated, and the capacity-fractionation voltage range is 2.5 - 4.20 V. The separator used is a single-layer ceramic separator with a thickness of 12 μm.

[0061] Example 2

[0062] In the positive electrode material, negative electrode material, and corresponding lithium-ion batteries provided in this embodiment, the only difference from the technical solution of Example 1 is that the raw materials of the positive electrode slurry used include 95% of positive electrode active material, 3.5% of positive electrode conductive agent, and 1.5% of positive electrode binder according to the dry powder mass fraction. The raw materials of the negative electrode slurry used are 93% of negative electrode active material, 1.5% of conductive agent, 3.5% of binder, and 2.5% of thickening agent according to the dry powder mass fraction.

[0063] Example 3

[0064] In the positive electrode material, negative electrode material, and corresponding lithium-ion batteries provided in this embodiment, the only difference from the technical solution of Example 1 is that the positive electrode active material is a material of LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 with a coating of lithium phosphotungstate and Al2O3 on the outside. The finally prepared positive electrode material has the same double-sided surface density and compaction density as that of Example 1. The total coating amount of lithium phosphotungstate and Al2O3 is 0.5%, and the mass ratio of lithium phosphotungstate to Al2O3 is 1:1.

[0065] Comparative Example 1

[0066] In the positive electrode material, negative electrode material, and corresponding lithium-ion batteries provided in this comparative example, the only difference from the technical solution of Example 1 is that the directly used positive electrode active material is LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 material without any additional coating on its surface.

[0067] Comparative Example 2

[0068] In the positive electrode material, negative electrode material, and corresponding lithium-ion batteries provided in this comparative example, the only difference from the technical solution of Example 1 is that the used positive electrode active material is LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1The O2 material is used as the base material, and the Al2O3 material is coated on its surface. The coating method can refer to the coating method of Al2O3 in Example 1 of Paragraph 56 of the specification text of the invention patent application CN115172719A.

[0069] Comparative Example 3

[0070] In the positive electrode material, negative electrode material and corresponding lithium-ion battery provided in this comparative example, the only difference from the technical solution of Example 1 is that: the positive electrode material uses ternary LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 as the positive electrode active material, and only ammonium tungstate is coated on the surface of the positive electrode active material.

[0071] Comparative Example 4

[0072] In the positive electrode material, negative electrode material and corresponding lithium-ion battery provided in this comparative example, the only difference from the technical solution of Comparative Example 4 is that: only ammonium phosphate is coated on the surface of the positive electrode active material. That is, ammonium tungstate is replaced with ammonium phosphate.

[0073] Comparative Example 5

[0074] In the positive electrode material, negative electrode material and corresponding lithium-ion battery provided in this comparative example, the only difference from the technical solution of Example 1 is that: the positive electrode material uses ternary LiNi 0.8 Co 0.1 Mn 0.1 O2 as the positive electrode active material (i.e., the existing high-nickel positive electrode material).

[0075] Test Example: Verification of the cycle performance and thermal stability (safety) of lithium-ion batteries

[0076] 1. Energy density test

[0077] Among the lithium-ion batteries prepared in the above examples and comparative examples, no less than 10 lithium batteries were selected for weighing, and the average weight was 0.950 kg; then the lithium batteries were charged and discharged at 1C / 1C, the voltage range was 2.5 - 4.4V, the capacity was ≥80 Ah, and the voltage platform was 3.72V. Taking Example 1 as an example, the energy density was calculated as follows: (80 × 3.72) / 0.950 = 313 Wh / kg. Similarly, the energy density of the lithium battery in Example 2 was 320 Wh / kg. It can be seen that the energy density of the lithium-ion batteries prepared by the method of the present invention is not less than 300 Wh / kg.

[0078] 2. Cycle stability test

[0079] The fully charged lithium-ion batteries in the above examples and comparative examples were tested for their respective cycle stabilities under the cycle conditions in Table 1 below.

[0080] Table 1 Cycling Conditions

[0081]

[0082] The test results are shown in Table 2 below. From the test data in the table, it can be concluded that the battery cycling performance of this technical solution is more excellent than that of Comparative Examples 1-6.

[0083] Table 2 Cycling Performance Test Results

[0084]

[0085] 3. Safety Test

[0086] Place the fully charged lithium-ion batteries of the above-mentioned examples and comparative examples in the ARC calorimeter cavity, heat up to the thermal runaway of the battery, and record the thermal runaway start temperature T1, the thermal runaway maximum temperature T max , and the thermal runaway start time t1. The test results are shown in Table 3 below.

[0087] Table 3 Comparison of Thermal Stability Experiment Results

[0088]

[0089]

[0090] From the test results in Table 3, it can be concluded that: the thermal runaway start temperature and the maximum temperature of the batteries (Examples 1-3) of this technical solution are much higher than those of the conventional technical solutions (Comparative Examples 1-5), and the thermal runaway start time is also much later than that of the conventional technical solutions, indicating that the safety performance of the battery has been greatly improved.

[0091] The above specific embodiments have described the implementation of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and the technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple variations all belong to the protection scope of the present invention.

Claims

1. A cathode material, characterized in that, It includes a positive electrode current collector and a positive electrode paste coated on the surface of the positive electrode current collector. The raw materials of the positive electrode paste include a positive electrode active material; the positive electrode active material includes LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 material.

2. The cathode material according to claim 1, characterized in that, The coating amount of lithium phosphotungstate in the positive electrode active material is 0.1-1.0% of the total mass of the positive electrode active material.

3. The cathode material according to claim 1, characterized in that, The described LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 The preparation method of O2 includes: sintering nickel-cobalt-manganese precursor Ni x Co y Mn z (OH)2, lithium carbonate Li2CO3, and Al(OH)3 at high temperature to obtain LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2; wherein the lithium carbonate is in an excess of 5% - 10%.

4. The cathode material according to claim 1, characterized in that, The preparation method of the positive electrode active material includes: mixing LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 O2 with ammonium tungstate and ammonium phosphate in a mass ratio of 100:(0.1 - 2.0):(0.1 - 2.0), sintering, sieving, and demagnetizing to obtain the finished product of the positive electrode active material.

5. The cathode material according to claim 4, characterized in that, LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 The mass ratio of O2 to ammonium tungstate and ammonium phosphate is 100:0.8:0.

8.

6. The cathode material according to claim 1, characterized in that, The dry powder raw materials of the positive electrode material are by weight percentage: 95-97.5% of positive electrode active material, 1.5-3.5% of positive electrode conductive agent, and 1-2% of positive electrode binder.

7. The cathode material according to claim 6, characterized in that, The positive electrode conductive agent is at least one of conductive carbon black, carbon nanotubes, carbon fibers, and graphene.

8. The cathode material according to claim 6, characterized in that, The positive electrode binder is polyvinylidene fluoride and / or polyimide.

9. The cathode material according to claim 1, characterized in that, The LiNi 0.6 Co 0.2 Al 0.1 Mn 0.1 The surface of the O2 material is also coated with an auxiliary material, and the auxiliary material is at least one of Al2O3, AlF3, and TiO2.

10. The cathode material according to claim 9, wherein The mass ratio of the lithium phosphotungstate to the auxiliary material is 1:(0.5-2.0).

11. The cathode material according to claim 10, wherein The auxiliary material is Al2O3, and the mass ratio of the lithium phosphotungstate to the auxiliary material is 1:

1.

12. The cathode material according to claim 1, characterized in that, The positive electrode current collector is an aluminum foil with a thickness of 10-14 μm.

13. The cathode material according to claim 1, wherein The double-sided areal density of the positive electrode material is 3-5 g / 100 cm 2 , and the tap density is 3.40-3.65 g / cm 3 .

14. A lithium-ion battery, characterized in that, It includes a positive electrode sheet prepared by using the positive electrode material according to any one of claims 1-13.

15. The lithium-ion battery according to claim 14, wherein, It further includes a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode material coated on the surface of the negative electrode current collector, and the negative electrode material includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and a negative electrode thickener.

16. The lithium-ion battery according to claim 15, characterized in that, The dry powder raw materials of the negative electrode material are by weight percentage: 93-97% of negative electrode active material, 0.5-1.5% of negative electrode conductive agent, 1.5-3.5% of negative electrode binder, and 0.5-3% of negative electrode thickener.

17. The lithium ion battery according to claim 15, wherein The negative electrode active material includes silicon carbon / silicon oxide compound.

18. The lithium-ion battery according to claim 15, wherein The negative electrode current collector is a copper foil with a thickness of 5-8 μm.

19. The lithium ion battery according to claim 15, wherein The double-sided surface density of the negative electrode material is 1.6 - 2.0 g / 100 cm 2 ; the tap density is 1.55 - 1.65 g / cm 3 .

20. An electrical device, characterized in that, It includes a lithium ion battery according to any one of claims 14-19.

Images