Composite lithium-supplementing agent and use thereof, positive electrode material, positive electrode sheet, lithium battery, battery module, and electrical apparatus

Abstract

The present disclosure relates to the technical field of secondary batteries. Disclosed are a composite lithium-supplementing agent and a use thereof, a positive electrode material, a positive electrode sheet, a lithium battery, a battery module, and an electrical apparatus. A lithium-supplementing agent containing Ni2+ or Ni3+ is added on the basis of a lithium-rich-based transition metal oxide (such as lithium iron oxide LFO), the lithium-supplementing agent can have some of Ni3+ / Ni4+ ions in a reaction system, and under an electrochemical action, the Ni3+ / Ni4+ ions react with a small number of O2- ions subsequently generated by LFO, so as to produce NiO / NiO2 and other substances, thereby reducing the ring-opening reaction between O2- ions and an electrolyte, and further reducing gas production and being conducive to improving the cycle performance of a battery.

Description

Composite lithium supplement and its application, positive electrode material, positive electrode sheet, lithium battery, battery module and power device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to application number 2023116727049 filed with the Patent Office of China on December 7, 2023, entitled “A composite lithium supplement and its application, positive electrode sheet, lithium battery and electrical device,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of secondary batteries, and in particular to a composite lithium supplement and its application, a positive electrode material, a positive electrode sheet, a lithium battery, a battery module, and an electrical device. Background Art

[0004] Lithium-ion batteries, with their high energy efficiency, long cycle life, low maintenance, and flexible power and energy characteristics, are gaining increasing popularity in automotive propulsion and energy storage. However, with the widespread adoption of electric vehicles, the pursuit of lithium-ion batteries with higher energy density is a common goal. Under many design concepts and material systems, further increases in energy density often come at the expense of battery safety, power, and lifespan.

[0005] Improving battery energy density by reducing the initial loss of positive and negative electrode materials is a promising improvement method. This method increases battery energy by increasing the number of active lithium ions, mainly achieved by adding positive or negative electrode additives, commonly known as lithium supplements. Among them, negative electrode lithium supplements require the introduction of metallic lithium or alkyl lithium, which has high environmental and process requirements and is more difficult to implement. Positive electrode lithium supplements, on the other hand, only require a small amount of lithium supplement (generally 1-3%) to be mixed into the positive electrode active material. This can be done without changing any front-end or mid-stage process equipment, making it very simple to operate and easy to implement, making it the preferred choice of many battery companies.

[0006] Usually, the positive electrode lithium replenisher is a lithium-rich oxide material, such as Li5FeO4, Li2NiO2, Li5CoO6, Li3N and other materials. The method of using the positive electrode lithium replenisher additive is generally to mix it with the main positive electrode material during homogenization, and the addition amount is between 0.5% and 5%. Taking Li5FeO4 as an example, its mechanism of action is: during the first charging process, the lithium replenisher will release a specific capacity of >600mAh / g, and the first discharge capacity is generally 30~40mAh / g. It produces excess lithium ions to replenish the lithium loss of the graphite negative electrode in the first effect and releases oxygen. The Li5FeO4 lithium replenisher has two charging platforms during the first charging process, which are around 3.5~3.6V and 3.9~4.0V. Li5FeO4 will undergo a delithiation reaction at each platform, and will eventually generate LiFeO2 and produce O2. The chemical reaction of the first charge of Li5FeO4 is as follows:

[0007] Li5FeO4→Li3FeO 3.5 +0.25O2↑+2Li + +2e - (3.5V);

[0008] Li3FeO 3.5 →LiFeO2+0.75O2↑+2Li + +2e - (4.0V);

[0009] Overall equation:

[0010] Li5FeO4→LiFeO2+O2↑+4Li + +4e - .

[0011] It can be seen that oxygen is produced during the decomposition of lithium-rich lithium ferrite (Li5FeO4) into lithium ferrite, and the oxygen reacts with the electrolyte to produce other gases.

[0012] From the first cycle charging principle, we can know that in the system with LFO (lithium ferrite), the gas produced in the first cycle of formation is mainly O2, with some CO2 and CO, and some H2O in the electrolyte is electrolyzed to form H2. In the subsequent aging and storage process, some O2 dissolves in the electrolyte to form O 2- / O - Free radicals, in subsequent cycles and high temperature storage, O 2- / O - Free radicals will catalyze the ring opening of the solvent EC (ethylene carbonate) in the electrolyte and react to form gases such as methane, ethylene, and CO2.

[0013] In general, after adding LFO lithium supplement, gas production will occur during the test process after the battery preparation is completed. The generation of gas will affect the battery's cycle and high-temperature performance, etc.

[0014] In view of this, the present disclosure is proposed.

[0015] Summary of the Invention

[0016] The purpose of the present disclosure is to provide a composite lithium supplement and its application, positive electrode material, positive electrode sheet, lithium battery, battery module and power device, aiming to effectively reduce gas production during formation and storage, and effectively improve the electrochemical performance of the battery.

[0017] The present disclosure is achieved as follows:

[0018] In a first aspect, the present disclosure provides a composite lithium supplement agent, comprising a lithium-rich transition metal oxide and a lithium-supplement-like agent, wherein the lithium-rich transition metal oxide is selected from at least one of lithium ferrite and lithium cobaltate;

[0019] The mass ratio of the lithium-rich transition metal oxide to the lithium-replenishing agent is (0.2-10):1; the chemical formula of lithium ferrite is Li5FeO4, and the lithium-replenishing agent contains nickel, and the valence of the nickel element is at least one of positive divalent or positive trivalent.

[0020] In an optional embodiment, the lithium-like supplement is selected from at least one of Li2NiO2, LiNiO2 and lithium nickel cobalt manganate.

[0021] In an optional embodiment, the lithium-like supplement is Li2NiO2.

[0022] In an optional embodiment, the mass ratio of the lithium-rich transition metal oxide to the lithium-supplementing agent is (2-4):1.

[0023] In an optional embodiment, the mass ratio of the lithium-rich transition metal oxide to the lithium-supplementing agent is 3:1.

[0024] In a second aspect, the present disclosure further provides the use of the composite lithium replenisher in the above embodiment as a positive electrode lithium replenisher in a lithium-based positive electrode material.

[0025] In a third aspect, the present disclosure further provides a positive electrode material, which comprises a lithium-based positive electrode material and a composite lithium supplement agent in any of the above embodiments.

[0026] In an optional embodiment, the lithium-based positive electrode material is selected from at least one of lithium titanate, lithium cobaltate, lithium iron phosphate, lithium manganese iron phosphate, and lithium nickel cobalt manganese oxide.

[0027] In a fourth aspect, the present disclosure further provides a positive electrode plate, comprising a current collector and the positive electrode material according to any of the above embodiments disposed on the current collector.

[0028] In an optional embodiment, the mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is (0.5-5.0):100.

[0029] In an optional embodiment, the mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is (1-3):100.

[0030] In an optional embodiment, the mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is 2:100.

[0031] In an optional embodiment, a binder and a conductive agent are further attached to the current collector, and the mass ratio of the lithium-based positive electrode material, the binder and the conductive agent is 100:(3-10):(3-10).

[0032] In an optional embodiment, the binder is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride, styrene-butadiene rubber and polyvinyl alcohol.

[0033] In an optional embodiment, the conductive agent is selected from at least one of carbon nanotubes, Super-P and graphene.

[0034] In a fifth aspect, the present disclosure further provides a lithium battery comprising the positive electrode sheet in any of the above embodiments.

[0035] In an optional embodiment, a negative electrode plate is further included, and the negative electrode active material in the negative electrode plate is graphite.

[0036] In a sixth aspect, a battery module includes the lithium battery of the aforementioned embodiment.

[0037] In a seventh aspect, the present disclosure provides an electrical device comprising the lithium battery or battery module of the aforementioned embodiment.

[0038] The present invention has the following beneficial effects: by adding Ni-containing 2+ or Ni 3+ A lithium-like supplement, which will have some (divalent and trivalent) Ni in the reaction system 2+ / Ni 3+ ions, Ni 2+ / Ni 3+ Under the electrochemical action, ions react with LFO to produce a small amount of O 2- / O - Ion reaction produces NiO / NiO2 and other substances, reducing O 2- / O - The ions open the ring and react with the solvent EC (ethylene carbonate) in the electrolyte to form gases such as methane, ethylene, and CO2, which can significantly reduce the gas production and help improve the cycle performance of the battery. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0040] An embodiment of the present disclosure provides a composite lithium supplement, including a lithium-rich transition metal oxide and a lithium-supplement-like agent. The lithium-rich transition metal oxide is selected from at least one of lithium ferrite (chemical formula Li5FeO4) and lithium cobaltate, and can be any one or two of the above. The lithium-supplement-like agent contains nickel, and the valence of the nickel element is at least one of positive divalent or positive trivalent.

[0041] It should be noted that the composite lithium replenisher provided in the embodiments of the present disclosure is suitable for lithium-based positive electrode material systems (such as lithium iron phosphate (LFP) / graphite systems). When used as a positive electrode lithium replenisher in this system, it can significantly improve and reduce gas production during formation and storage, effectively improving battery performance.

[0042] In some embodiments, the quasi-lithium supplement is selected from at least one of Li2NiO2, LiNiO2, and lithium nickel cobalt manganese oxide, and may be any one or more of the above. Preferably, the quasi-lithium supplement is Li2NiO2, which is also a lithium supplement and can be used as a lithium supplement to reduce gas production, thereby improving battery cycle life and storage.

[0043] It should be noted that the first cycle charging capacity of lithium-rich nickel oxide (LNO) is 400-410mAh / g, and the discharge capacity is about 140-150mAh / g. It can be used as a lithium supplement to make up for the lithium loss in the first cycle and work together with LFO to supplement lithium. During use, lithium supplements will have some Ni in the reaction system. 3+ / Ni 4+ ions, Ni 3+ / Ni 4+ Under the electrochemical action, ions react with LFO to produce a small amount of O 2- Ion reaction produces NiO / NiO2 and other substances, reducing O 2- / O - The ions open the ring and react with the solvent EC (ethylene carbonate) in the electrolyte to form gases such as methane, ethylene, and CO2, which can significantly reduce the gas production and help improve the cycle performance of the battery.

[0044] In some embodiments, the mass ratio of the lithium-rich transition metal oxide and the lithium-replenishing agent is (0.2-10):1; preferably (2-4):1; more preferably 3:1. By optimizing the mass ratio of the lithium-rich transition metal oxide and the lithium-replenishing agent, the gas production can be significantly reduced while ensuring the electrochemical performance of the battery.

[0045] Specifically, the mass ratio of the lithium-rich transition metal oxide to the lithium-supplementing agent can be 0.2:1, 0.5:1, 0.8:1, 1.0:1, 2.0:1, 3.0:1, 4.0:1, 5.0:1, 6.0:1, 7.0:1, 8.0:1, 9.0:1, 10.0:1, etc.

[0046] It should be noted that adding too much lithium-rich nickel oxide (LNO) can have some adverse effects: (1) When the LNO ratio is too high, its discharge capacity is relatively low, resulting in a low overall cell capacity (the overall cell capacity is generally calculated based on the discharge capacity); (2) Since NiO / NiO2 and other substances generated by absorbing oxygen are electrochemically inactive, they increase the battery's impedance and reduce the battery's rate performance. When the LNO ratio is too low, the generated oxygen cannot be completely reacted with nickel ions, resulting in an inability to effectively control the gas production.

[0047] In addition, when the addition ratio of LNO is too low, the generated oxygen will not be completely reacted by nickel ions, which will also result in the gas production not being able to be effectively controlled.

[0048] The disclosed embodiments also provide for the use of a composite lithium replenisher as a positive electrode lithium replenisher in a lithium-based positive electrode material. The lithium-based positive electrode material is selected from at least one of lithium titanate, lithium cobaltate, lithium iron phosphate, lithium manganese iron phosphate, and lithium nickel cobalt manganese oxide. It can be any one or more of the above. The application of the composite lithium replenisher to the above lithium-based positive electrode materials can effectively reduce gas production.

[0049] The present disclosure also provides a positive electrode material comprising a lithium-based positive electrode material and the aforementioned composite lithium supplement. The present disclosure also provides a positive electrode plate comprising a current collector and the aforementioned positive electrode material disposed on the current collector. The introduction of the composite lithium supplement significantly reduces battery gas production and improves the battery's electrochemical performance.

[0050] It should be noted that the preparation process of the positive electrode sheet is as follows: lithium iron phosphate, a composite lithium supplement, a binder, and a conductive agent are mixed to obtain a positive electrode slurry, the positive electrode slurry is coated on the positive electrode current collector, and the positive electrode sheet is obtained after drying. The composite lithium supplement is introduced during the preparation of the positive electrode slurry, and a dispersant (such as NMP) can be introduced during the process to improve the uniformity of the slurry. The positive electrode sheet is obtained after conventional coating and drying processes.

[0051] Furthermore, the mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is (0.5-5.0):100, preferably (1-3):100, and more preferably 2:100. By controlling the amount of the composite lithium supplement agent, gas production can be further reduced and the electrochemical performance of the battery can be improved. If the amount of the composite lithium supplement agent is too small, the gas production cannot be effectively controlled. If the amount of the composite lithium supplement agent is too large, the electrochemical performance of the battery will be affected.

[0052] Specifically, the mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material can be 0.5:100, 1.0:100, 2.0:100, 3.0:100, 4.0:100, 5.0:100, etc.

[0053] In some embodiments, in the positive electrode slurry, the mass ratio of lithium iron phosphate, binder, and conductive agent is 100:(3-10):(3-10). The amount of dispersant used is not limited, as long as the effect of homogenization is achieved. Specifically, the mass ratio of lithium iron phosphate, binder, and conductive agent can be 100:3:3, 100:4:4, 100:5:5, 100:6:6, 100:7:7, 100:8:8, 100:9:9, 100:10:10, etc. The amounts of binder and conductive agent can be the same or slightly different.

[0054] Furthermore, the binder is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride, styrene-butadiene rubber and polyvinyl alcohol, and may be any one or more of the above; the conductive agent is selected from at least one of carbon nanotubes, Super-P and graphene, and may be any one or more of the above.

[0055] Furthermore, the type of the positive electrode current collector is not limited and may be aluminum foil.

[0056] The embodiments of the present disclosure also provide a lithium battery, including the positive electrode plate in the above embodiments. By improving the positive electrode plate, the gas production of the battery can be significantly reduced, and electrochemical performance can be improved.

[0057] In some embodiments, the negative electrode sheet in the lithium battery can be a graphite negative electrode, and the negative electrode sheet is prepared using graphite as the negative electrode active material. The negative electrode sheet can be purchased from the market or prepared independently.

[0058] In some embodiments, a graphite negative electrode sheet can be prepared using existing preparation methods. Specifically, the negative electrode slurry (graphite slurry) is evenly coated on the surface of the negative electrode current collector and dried to obtain the negative electrode sheet. The negative electrode current collector can be of any type, such as copper foil; the specific concentration of the graphite slurry is not limited.

[0059] A secondary battery is assembled using positive and negative electrode sheets. When assembling a secondary battery, a separator, an electrolyte, etc. are also required, and the specific types are not limited.

[0060] Furthermore, when the secondary battery is assembled, the charging N / P ratio is controlled to be 1.01-1.15, such as 1.01, 1.03, 1.05, 1.08, 1.10, 1.12, 1.15, etc.

[0061] The embodiment of the present disclosure further provides a battery module, including the above-mentioned lithium battery, with no limit on the number of lithium batteries and no limit on the arrangement thereof.

[0062] The present disclosure also provides an electrical device comprising the lithium battery and an electrical appliance, wherein the lithium battery can power the electrical appliance, and the type of the electrical appliance is not limited. Specifically, the electrical device can be a mobile device, an electric vehicle, or the like.

[0063] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0064] Example 1

[0065] This embodiment provides a method for preparing a lithium battery, and the specific steps are as follows:

[0066] (1) Preparation of positive electrode sheet

[0067] Lithium iron phosphate (LFP, LiFePO4), lithium ferrite (LFO, Li5FeO4), lithium nickelate (LNO, Li2NiO2), polyvinylidene fluoride and carbon nanotubes were mixed. The mass ratio of the two lithium supplements, lithium ferrite and lithium nickelate, was 10:1, and the mass ratio of lithium iron phosphate, composite lithium supplement, polyvinylidene fluoride and carbon nanotubes was 98:2:5:5 (i.e., the addition amount of composite lithium supplement was 2%). After adding N-methylpyrrolidone to the slurry, the mixture was coated on aluminum foil (aluminum foil roll with a thickness of 13 μm and a width of 220 mm). The coating surface density was about 15-20 mg / cm 2 , and after drying, the positive electrode sheet is obtained.

[0068] (2) Preparation of negative electrode sheet

[0069] Graphite, binder, dispersant and conductive agent were mixed in a mass ratio of 96.6:1.8:1.0:0.6 to obtain graphite slurry. The graphite slurry was evenly coated on a copper foil roll (12 μm thick and 222 mm wide). The coating surface density was about 8 mg / cm 2 , and after drying, the negative electrode sheet is obtained.

[0070] (3) Preparation of LFP full cell

[0071] The prepared negative electrode sheet and positive electrode sheet are assembled, injected and formed into a battery. The designed charging N / P ratio of the full battery is about 1.07, and the LFP full battery is prepared according to the full battery preparation method. Specific steps: The obtained electrode sheet is rolled to obtain positive and negative electrode sheets with a certain compaction density (the positive electrode sheet has a compaction density of 2.45g / cm 3 , the compaction density of the negative electrode is 1.6g / cm 3 ), followed by electrode slitting and laser die-cutting. The resulting positive and negative electrode sheets are stacked to assemble a battery cell, with 25 layers. The cells are then placed in a case, dried, and finally filled with electrolyte at a rate of 3.5g / Ah. The resulting full battery is then subjected to quantization, capacity analysis, and testing.

[0072] Examples 2-7

[0073] The only difference from Example 1 is that the mass ratios of the two lithium supplements, lithium ferrite and lithium nickelate, in Examples 2-7 are 5:1, 3:1, 2:1, 1:1, 1:2 and 1:5, respectively.

[0074] Examples 8-12

[0075] The only difference from Example 1 is: the mass ratio and total addition amount of the two lithium supplements, lithium ferrite and lithium nickelate. In Examples 8-12, LFO:LNO=3:1, and the addition amounts of the composite lithium supplement are 0.5%, 1%, 2%, 3% and 4%, respectively.

[0076] Example 13

[0077] The only difference from Example 3 is that Li2NiO2 is replaced by an equal amount of LiNiO2(L1NO). That is, the mass ratio of the two lithium supplements, lithium ferrite and LiNiO2, in Example 13 is 3:1, that is, the addition amount of the composite lithium supplement is 2%.

[0078] Example 14

[0079] The only difference from Example 3 is that Li2NiO2 is replaced by an equal amount of NCM811, LFO:NCM811=3:1.

[0080] That is, in Example 14, the mass ratio of the two lithium supplements, lithium ferrite and NCM811, is 3:1, and the addition amount of the composite lithium supplement is 2%.

[0081] Comparative Example 1

[0082] The only difference from Example 1 is that no lithium supplement agent is introduced during the preparation process.

[0083] Comparative Example 2

[0084] The only difference from Example 1 is that a single LFO is used as the lithium supplement agent, and the added amount is the same as the added amount of the composite lithium supplement agent in Example 1, that is, 2% lithium supplement agent content.

[0085] Test Example 1

[0086] The capacity and cycle performance of the lithium batteries prepared in the test examples and comparative examples are shown in Table 1.

[0087] Test conditions: Cells were tested using Xinwei Heng current charge and discharge equipment. Cell capacity testing conditions were 0.33C charge / 0.33C discharge, and the resulting 0.33C discharge capacity (i.e., cell capacity). Cell cycle testing conditions were 45°C, 1C / 1C charge and discharge.

[0088] Table 1 Full battery capacity and cycle performance of different proportions of composite lithium supplements

[0089] The high-temperature storage gas production of the lithium batteries prepared in the test examples and comparative examples is shown in Table 2.

[0090] Test method: First, perform the cell volume test using the drainage method. Then fully charge the cell at 0.33C and store it in a constant temperature and humidity chamber at 55°C for 7, 14, 21 days, etc. Perform the cell volume test (drainage method) on the corresponding days.

[0091] Table 2 Different proportions of composite lithium supplement and gas production during high temperature storage

[0092] As shown in Tables 1 and 2, the optimal ratio of the composite lithium supplement is LFO / LNO = 3:1, and the optimal addition level is 2%. This composite lithium supplement has the highest capacity, the lowest gas production, and the best cycling performance. (Taking a comprehensive look at both cycling and gas production, optimal overall performance is achieved when both gas production and cycling are excellent.)

[0093] The above are merely preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure. Industrial Applicability

[0094] The present invention discloses a method of adding Ni-containing 2+ or Ni 3+ A lithium supplement that can reduce O 2-The ions react with the electrolyte to produce a ring-opening reaction, thereby reducing gas production, which is beneficial to improving the cycle performance of the battery and has good industrial application prospects.

Claims

1. A composite lithium supplement, characterized in that: It comprises a lithium-rich transition metal oxide and a lithium-supplementing agent, wherein the lithium-rich transition metal oxide is selected from at least one of lithium ferrite and lithium cobalt oxide; The mass ratio of the lithium-rich transition metal oxide to the lithium-replenishing agent is (0.2-10):1; the chemical formula of the lithium ferrite is Li5FeO4, and the lithium-replenishing agent contains nickel element, and the valence of the nickel element is at least one of positive divalent or positive trivalent.

2. The composite lithium supplement according to claim 1, characterized in that: The lithium-supplementing agent is selected from at least one of Li2NiO2, LiNiO2 and lithium nickel cobalt manganese oxide.

3. The composite lithium supplement according to claim 1 or 2, characterized in that: The lithium supplement agent is Li2NiO2.

4. The composite lithium supplement according to any one of claims 1 to 3, characterized in that: The mass ratio of the lithium-rich transition metal oxide to the lithium-supplementing agent is (2-4):

1.

5. The composite lithium supplement according to any one of claims 1 to 4, characterized in that: The mass ratio of the lithium-rich transition metal oxide to the lithium-supplementing agent is 3:

1.

6. Use of the composite lithium supplement agent according to any one of claims 1 to 5 as a positive electrode lithium supplement agent in a lithium-based positive electrode material.

7. A positive electrode material, characterized in that: The positive electrode material comprises a lithium-based positive electrode material and a composite lithium supplement according to any one of claims 1 to 5.

8. The positive electrode material according to claim 7, characterized in that The lithium-based positive electrode material is selected from at least one of lithium titanate, lithium cobaltate, lithium iron phosphate, lithium iron manganese phosphate, and lithium nickel cobalt manganese oxide.

9. A positive electrode sheet, characterized in that: The invention comprises a current collector and the positive electrode material as claimed in claim 7 or 8 arranged on the current collector.

10. The positive electrode sheet according to claim 9, characterized in that: The mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is (0.5-5.0):

100.

11. The positive electrode sheet according to any one of claims 9 to 10, characterized in that: The mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is (1-3):

100.

12. The positive electrode sheet according to any one of claims 9 to 11, characterized in that: The mass ratio of the composite lithium supplement agent to the lithium-based positive electrode material is 2:

100.

13. The positive electrode sheet according to any one of claims 9 to 12, characterized in that: The current collector is also attached with a binder and a conductive agent, and the mass ratio of the lithium-based positive electrode material, the binder and the conductive agent is 100:(3-10):(3-10).

14. The positive electrode sheet according to claim 13, characterized in that: The binder is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride, styrene-butadiene rubber and polyvinyl alcohol.

15. The positive electrode sheet according to claim 13, characterized in that: The conductive agent is selected from at least one of carbon nanotubes, Super-P and graphene.

16. A lithium battery, characterized in that: A positive electrode sheet comprising any one of claims 9 to 15.

17. The lithium battery according to claim 16, characterized in that: It also includes a negative electrode plate, in which the negative electrode active material is graphite.

18. A battery module, characterized in that: Includes the lithium battery described in claim 16 or 17.

19. An electrical device, characterized in that: The invention comprises the lithium battery described in any one of claims 16 to 17 or the battery module described in claim 18.

Images