Positive electrode lithium supplementing material and preparation method and application thereof

Abstract

The embodiment of the invention relates to a positive electrode lithium supplementing material and a preparation method and application thereof. The positive electrode lithium supplementing material is of a core-shell structure, an inner core is a porous carrier with lithium supplementing active substances distributed in pores, and an outer shell is a solid electrolyte layer covering the surface of the porous carrier; the particle size of the lithium supplement active substance is 1 nm to 200 nm; the pore size of the porous carrier is 0.1 nm to 250 nm. In the positive electrode lithium supplement material, the active lithium supplement component is nano particles which are distributed in the porous carrier of the inner core, and the positive electrode lithium supplement material has high lithium supplement capacity due to relatively small granularity and relatively high dispersity, so that the first cycle efficiency and the cycle life of the battery can be improved and prolonged by relatively small usage amount; the solid electrolyte layer on the outer layer isolates the lithium supplement active component from the outside and provides the function of an ion guide channel, so that the stability and the ion guide capability of the material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and particularly to a cathode lithium supplement material, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, due to the negative impacts brought about by the rapid development of the social economy, such as environmental pollution and the sharp consumption of oil resources, various countries have been actively developing technologies related to clean energy lithium-ion batteries. With the progress of battery technology further promoting the development of the industry, higher requirements for battery performance have been put forward in the fields of electric vehicles, energy storage devices, and various consumer electronic products.

[0003] As the battery industry technology gradually moves towards perfection, some lithium-ion batteries have been commercially applied on a large scale, but their energy density, stability, and cycle life still cannot fully meet the usage requirements in complex environments. This is mainly attributed to the formation of a solid electrolyte interface (SEI) film and a cathode electrolyte interface (CEI) film during the charge and discharge process of lithium-ion batteries, resulting in irreversible loss of some active substances, reducing the first-cycle efficiency of the battery, and thus affecting the cycle life and safety performance of the battery during the battery cycle.

[0004] Regarding the above problems, adding an active lithium supplement substance in an appropriate amount to the cathode is a good mainstream method. However, the current lithium supplement materials generally have a low lithium supplement capacity, and there are problems of poor air stability and poor ion conduction ability that need to be solved.

[0005] Therefore, it is very necessary to develop a lithium supplement material with high capacity and good stability. Summary of the Invention

[0006] The purpose of the present invention is to provide a cathode lithium supplement material, a preparation method thereof, and an application thereof. Through the adsorption of the lithium supplement active material by a porous carrier and the coating of an in-situ solid electrolyte, a simple and feasible preparation of the cathode lithium supplement material is realized, which can effectively improve the stability and ion conduction ability of the material.

[0007] To this end, in a first aspect, an embodiment of the present invention provides a cathode lithium supplement material, which has a core-shell structure. Among them, the inner core is a porous carrier with lithium supplement active substances distributed in the pores, and the outer shell is a solid electrolyte layer coated on the surface of the porous carrier; the particle size of the lithium supplement active substance is 1 nm - 200 nm; the pore size of the porous carrier is 0.1 nm - 250 nm.

[0008] Preferably, the porous carrier includes one or more of: activated carbon, expanded graphite, activated carbon fiber, carbon nanotube, porous acetylene black, porous aluminum foam, porous nickel foam, porous alumina, porous zirconia, porous magnesia, porous silicon carbide, and porous silicon nitride;

[0009] The lithium supplement active material includes one or a mixture of lithium oxide, lithium oxalate, lithium acetate, lithium ferrite, lithium cuprate, lithium nickelate, and lithium hydroxide.

[0010] Preferably, the solid electrolyte includes one of NASICON-type solid electrolytes, perovskite-type solid electrolytes, garnet-type solid electrolytes, or halide electrolytes.

[0011] More preferably, the NASICON-type solid electrolyte specifically includes: Li 1+x A1 x A2 2+x (PO4)3, where x is between 0.01 and 0.5, A1 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and A2 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, and hafnium metal Hf;

[0012] The perovskite-type solid electrolyte specifically includes: Li 3x A3 2 / 3-x A4O3, where x is between 0.01 and 0.5, A3 is one or more of La, Al, Mg, Fe, Ta, and A4 is one or more of Ti, Nb, Sr, Pr;

[0013] The garnet-type solid electrolyte specifically includes: Li7A53A62O 12 , where A5 is one or more of La, Ca, Sr, Ba, K, and A6 is one or more of Zr, Ta, Nb, Hf;

[0014] The halide electrolyte specifically includes Li 2+x-y ZrCl 6-x-y O x , where x is between 0 and 0.6.

[0015] Preferably, the mass ratio of the porous carrier to the lithium supplement active material is 1:0.1 - 5;

[0016] The mass ratio of the inner core to the outer shell is 1:0.02 - 0.3.

[0017] Preferably, the particle size of the porous carrier is 300 nm - 30 μm, and the specific surface area is 200 m 2 / g - 2000 m 2 / g; the thickness of the outer core of the solid electrolyte layer is 1 nm - 200 nm; the particle size of the positive electrode lithium supplement material is 1 nm - 150 μm.

[0018] Second, the embodiments of the present invention provide a preparation method of the positive electrode lithium supplement material described in the first aspect above. The preparation method includes:

[0019] Weigh the lithium supplement active material proportionally and dissolve it in the first solvent to obtain a mixed solution. Subsequently, add a porous carrier to the mixed solution and disperse it for 6 h - 72 h to adsorb the lithium supplement active material into the pores of the porous carrier; dry the mixed solution to obtain the core material;

[0020] Disperse the solid electrolyte material in the second solvent to make a slurry, and then add the slurry to the citric acid - ethylene glycol aqueous solution. Heat the solution to 70°C - 150°C to make the solution become a gel state, obtaining the coated solid electrolyte gel material;

[0021] Add the core material to the coated solid electrolyte gel material and disperse it evenly, then dry to remove the solvent. Transfer the obtained product to a heat treatment device and introduce an inert gas, and calcine it at 600°C - 1300°C for 1 h - 36 h. After cooling to room temperature, the positive electrode lithium supplement material can be obtained.

[0022] Preferably, the dispersion equipment includes one or more of a disperser, a stirrer, a ball mill, an ultrasonic machine, and a shaker;

[0023] The heat treatment device includes: one of a muffle furnace, a tube furnace, a rotary furnace, and a pusher furnace; the inert gas is one or more of nitrogen and argon.

[0024] In a third aspect, an embodiment of the present invention provides a positive electrode sheet, including the positive electrode lithium supplement material described in the first aspect above.

[0025] In a fourth aspect, an embodiment of the present invention provides a lithium - ion battery, including the positive electrode sheet described in the third aspect above.

[0026] The positive electrode lithium supplement material provided by the embodiment of the present invention has a nano - particle active lithium supplement component distributed in the porous carrier of the core. The smaller particle size and higher dispersibility endow it with a higher lithium supplement capacity, so that a smaller usage amount can improve the first - cycle efficiency and cycle life of the battery. The outer solid electrolyte layer isolates the lithium supplement active component from the outside world and provides the function of an ion - conducting channel, improving the stability and ion - conducting ability of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flowchart of the preparation method of the positive electrode lithium supplement material provided by the embodiment of the present invention;

[0028] Figure 2 It is the first - cycle charge - discharge test curves of Embodiment 1 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] An embodiment of the present invention provides a cathode lithium supplement material with a core-shell structure, wherein the inner core is a porous carrier with lithium supplement active substances distributed in the pores, and the outer shell is a solid electrolyte layer coated on the surface of the porous carrier.

[0031] The mass ratio of the porous carrier to the lithium supplement active substance is 1:0.1-5; the mass ratio of the inner core to the outer shell is 1:0.02-0.3.

[0032] The particle size of the lithium supplement active substance is 1nm-200nm; the pore size of the porous carrier is 0.1nm-250nm, the particle size of the porous carrier is 300nm-30μm, and the specific surface area is 200m 2 / g-2000m 2 / g; the outer core thickness of the solid electrolyte layer is 1nm-200nm; the particle size of the cathode lithium supplement material particles is 1nm-150um.

[0033] The porous carrier includes one or more of: activated carbon, expanded graphite, activated carbon fiber, carbon nanotube, porous acetylene black, porous aluminum foam, porous nickel foam, porous alumina, porous zirconia, porous magnesia, porous silicon carbide, porous silicon nitride.

[0034] The lithium supplement active substances include one or more mixtures of: lithium oxide, lithium oxalate, lithium acetate, lithium ferrite, lithium cuprate, lithium nickelate, lithium hydroxide.

[0035] The solid electrolyte includes one of: NASICON-type solid electrolyte, perovskite-type solid electrolyte, garnet-type solid electrolyte or halide electrolyte.

[0036] The NASICON-type solid electrolyte specifically includes: Li 1+x A1 x A2 2+x (PO4)3, where x is between 0.01-0.5, A1 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and A2 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, hafnium metal Hf; the perovskite-type solid electrolyte specifically includes: Li 3x A3 2 / 3-x A4O3, where x is between 0.01-0.5, A3 is one or more of La, Al, Mg, Fe, Ta, and A4 is one or more of Ti, Nb, Sr, Pr; the garnet-type solid electrolyte specifically includes: Li7A53A62O 12, where A5 is one or more of La, Ca, Sr, Ba, and K, and A6 is one or more of Zr, Ta, Nb, and Hf; the halide electrolyte specifically includes Li 2+x-y ZrCl 6-x-y O x , where x is between 0 and 0.6.

[0037] The above-mentioned cathode lithium supplement material of the present invention can be obtained through the following preparation method. The main steps are as Figure 1 shown.

[0038] Step 110, weigh the lithium supplement active substance in proportion and dissolve it in the first solvent to obtain a mixed solution. Subsequently, add a porous carrier to the mixed solution and disperse it for 6 h - 72 h to adsorb the lithium supplement active substance into the pores of the porous carrier; dry the mixed solution to obtain the core material;

[0039] Among them, the first solvent includes any one of water, ethanol, and N-methylpyrrolidone (NMP).

[0040] The dispersion equipment includes one or more of a disperser, a stirrer, a ball mill, an ultrasonic machine, and a shaker;

[0041] The mass ratio of the porous carrier to the lithium supplement active substance is 1:0.1 - 5.

[0042] Step 120, disperse the solid electrolyte material in the second solvent to make a slurry, and then add the slurry to the citric acid-ethylene glycol aqueous solution. Heat the solution to 70°C - 150°C to make the solution become a gel state to obtain the coated solid electrolyte gel material;

[0043] Among them, the second solvent is deionized water;

[0044] In the citric acid-ethylene glycol aqueous solution, the molar ratio of citric acid to ethylene glycol is 1:1 - 1:1.1; a citric acid ethylene glycol ester copolymer is formed through a heating reaction.

[0045] Step 130, add the core material to the coated solid electrolyte gel material and disperse it evenly, then dry to remove the solvent. Transfer the obtained product to a heat treatment device and introduce an inert gas, and calcine it at 600°C - 1300°C for 1 h - 36 h. After cooling to room temperature, the cathode lithium supplement material can be obtained.

[0046] Among them, the heat treatment device includes one of an atmosphere box furnace, a tube furnace, a rotary furnace, and a pusher furnace;

[0047] The inert gas is one or more of nitrogen and argon.

[0048] The dosage ratio of the core material added to the coated solid electrolyte gel material is ensured so that the mass ratio of the core to the shell in the obtained cathode lithium supplement material is 1:0.02 - 0.3.

[0049] The cathode lithium supplement material obtained above in the present invention can be used in the cathode plate of a lithium-ion battery. Since its active lithium supplement component is nanoparticles distributed in the porous carrier of the core, its small particle size and high dispersibility endow it with a high lithium supplement capacity. Thus, a small usage amount can improve the first-cycle efficiency and cycle life of the battery. The outer solid electrolyte layer isolates the lithium supplement active component from the outside and provides the function of an ion conduction channel, enhancing the stability and ion conduction ability of the material.

[0050] To more clearly illustrate the purpose and advantages of the present invention, the present invention will be further elaborated below in conjunction with embodiments. In addition, the embodiments described in the present invention are only partial embodiments. All other embodiments obtained by those skilled in the art without creative efforts based on the embodiments described in the present invention fall within the protection scope of the present invention. Additionally, it should be understood that these embodiments are only for more detailed illustration and should not be construed as limiting the present invention in any form, that is, it is not intended to limit the protection scope of the present invention.

[0051] Example 1

[0052] This example provides a preparation method for a cathode lithium supplement material, and the specific steps are as follows:

[0053] 1) Weigh 10 grams of lithium oxalate with an average particle size of 20 nm and dissolve it in water. Then add 5 grams of porous activated carbon with an average particle size of 1 μm thereto, and stir and disperse with a disperser for 24 h. Then heat and evaporate to remove the solvent to obtain the core material.

[0054] 2) Weigh 2 grams of lithium aluminum titanium phosphate (LATP) solid electrolyte material and disperse it in 8 grams of deionized water to obtain a slurry. Then add the obtained slurry to a citric acid - ethylene glycol aqueous solution with a molar ratio of 1:1 and stir and disperse evenly. Stir and heat the obtained mixed solution to 120 °C, and stop heating when the solution becomes a gel state to obtain the coated gel material.

[0055] 3) Add the core material obtained in step 1) to the coated gel material prepared in step 2), stir and disperse evenly, then heat and dry to remove the solvent. Transfer the remaining solid product to a tube furnace device, introduce a nitrogen atmosphere, and adjust the temperature of the tube furnace to 960 °C, hold for 3 h, and cool to room temperature to obtain the cathode lithium supplement material prepared in this example.

[0056] Example 2

[0057] This embodiment provides a preparation method of a cathode lithium supplement material, and the specific steps are as follows:

[0058] 1) Weigh 15 grams of lithium ferrite with an average particle size of 15 nm and dissolve it in NMP. Then add 4 grams of porous aluminum foam with an average particle size of 3 μm to it, and ball mill for 18 h with a ball mill. Then heat and evaporate to remove the solvent to obtain the core material;

[0059] 2) Weigh 5 grams of lithium lanthanum zirconate (LLZO) solid electrolyte material and disperse it in 15 grams of deionized water to obtain a slurry. Then add the obtained slurry to a citric acid-ethylene glycol aqueous solution with a molar ratio of 1:1.1 and stir to disperse evenly. Stir and heat the obtained mixed solution to 130 °C, and stop heating when the solution becomes a gel state to obtain the coating layer gel material;

[0060] 3) Add the core material obtained in step 1) to the coating layer gel material prepared in step 2), and stir to disperse evenly. Then heat and dry to remove the solvent, transfer the remaining solid product to a tube furnace device, introduce a nitrogen atmosphere, and adjust the temperature of the tube furnace to 1200 °C, keep it warm for 5 h, and cool to room temperature to obtain the cathode lithium supplement material prepared in this embodiment.

[0061] Example 3

[0062] This embodiment provides a preparation method of a cathode lithium supplement material, and the specific steps are as follows:

[0063] 1) Weigh 12 grams of lithium acetate with an average particle size of 25 nm and dissolve it in water. Then add 6 grams of carbon nanotubes with an average particle size of 800 nm to it, and stir and disperse with a disperser for 36 h. Then heat and evaporate to remove the solvent to obtain the core material;

[0064] 2) Weigh 2 grams of lithium germanium aluminum phosphate (LAGP) solid electrolyte material and disperse it in 8 grams of deionized water to obtain a slurry. Then add the obtained slurry to a citric acid-ethylene glycol aqueous solution with a molar ratio of 1:1 and stir to disperse evenly. Stir and heat the obtained mixed solution to 150 °C, and stop heating when the solution becomes a gel state to obtain the coating layer gel material;

[0065] 3) Add the core material obtained in step 1) to the coating layer gel material prepared in step 2), and stir to disperse evenly. Then heat and dry to remove the solvent, transfer the remaining solid product to a box-type atmosphere furnace device, introduce an argon atmosphere, and adjust the temperature of the rotary furnace to 940 °C, keep it warm for 12 h, and cool to room temperature to obtain the cathode lithium supplement material prepared in this embodiment.

[0066] Example 4

[0067] This embodiment provides a preparation method of a cathode lithium supplement material, and the specific steps are as follows:

[0068] 1) Weigh 16 g of lithium hydroxide with an average particle size of 15 nm and dissolve it in water. Then add 9 g of carbon nanotubes with an average particle size of 1 μm to it, and ultrasonicate for 8 h with an ultrasonic machine. Then heat and evaporate to remove the solvent to obtain the core material.

[0069] 2) Weigh 3 g of lithium lanthanum titanate (LLTO) solid electrolyte material and disperse it in 15 g of deionized water to obtain a slurry. Then add the obtained slurry to an aqueous solution of citric acid - ethylene glycol with a molar ratio of 1:1.05 and stir to disperse evenly. Stir and heat the obtained mixed solution to 120 °C, and stop heating when the solution becomes a gel state to obtain the coating gel material.

[0070] 3) Add the core material obtained in step 1) to the coating gel material prepared in step 2), and stir to disperse evenly. Then heat and dry to remove the solvent, transfer the remaining solid product to a rotary furnace device, introduce a nitrogen atmosphere, and adjust the rotary furnace temperature to 1250 °C, hold for 3 h, and cool to room temperature to obtain the positive electrode lithium supplement material prepared in this example.

[0071] Battery assembly and testing:

[0072] Use the positive electrode lithium supplement materials prepared in the above embodiments of the present invention as additives for the positive electrode material, mix them with lithium cobaltate positive electrode material at a mass ratio of 5:95 to form the positive electrode active material, and then homogenize them into a slurry with polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a mass ratio of 90:5:5. Then prepare a positive electrode sheet and assemble it into a button cell for testing.

[0073] Assembly of the button cell: Coat a positive electrode sheet containing the positive electrode lithium supplement material prepared in this example, a polypropylene (PP) separator, a graphite negative electrode sheet, and an electrolyte of 1 M LiPF6 (the solvent is ethylene carbonate EC + diethyl carbonate DEC with a volume ratio of 1:1), and assemble them into a button cell by a conventional method.

[0074] At the same time, use lithium cobaltate positive electrode material without adding the positive electrode lithium supplement material as the positive electrode active material, and prepare the button cell of Comparative Example 1 according to the same method above.

[0075] Perform the first - week discharge test of the button cell. The test method is: Constant - current charge at a rate of 0.1C until the voltage reaches 4.4V, then constant - voltage charge at 4.4V until 0.02C, then stand for 5 min, and then constant - current discharge at a rate of 0.1C until the voltage reaches 2.75V. Perform the first - week charge - discharge test on Example 1 and Comparative Example 1. The first - week charge - discharge test curves are as Figure 2 shown.

[0076] From Figure 2The comparison of curves shows that the positive electrode lithium supplement material provided in the embodiment of the present invention, as an additive to the positive electrode material, has an obvious lithium supplement effect, enabling the material to provide more active lithium. In the first cycle, the discharge specific capacity is significantly higher than that of the comparative example without adding the positive electrode lithium supplement material.

[0077] A 100-cycle charge-discharge test of the coin cell was carried out. The test method was as follows: Constant current charging was carried out at a rate of 0.1C until the voltage reached 4.4V, then it was left standing for 5 minutes, and then constant current discharging was carried out at a rate of 0.1C until the voltage reached 2.75V, and then it was left standing for 5 minutes. The above was a cycle of charge-discharge process, and the 100-cycle charge-discharge test was carried out according to the above method. The cycle capacity retention rate after 100 cycles is shown in Table 1.

[0078] Number Capacity retention rate after 100 cycles Example 1 95.57％ Example 2 94.96％ Example 3 93.84％ Example 4 94.92％ Comparative Example 1 90.74％

[0079] Table 1

[0080] The comparison of the test data in Table 1 shows that the positive electrode lithium supplement material provided in the embodiment of the present invention, as an additive to the positive electrode material, effectively improves the cycle performance of the battery.

[0081] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cathode lithium supplement material, characterized in that, The positive electrode lithium supplement material has a core-shell structure. Among them, the inner core is a porous carrier with lithium supplement active substances distributed in the pores, and the outer shell is a solid electrolyte layer coated on the surface of the porous carrier; the particle size of the lithium supplement active substances is 1 nm - 200 nm; the pore size of the porous carrier is 0.1 nm - 250 nm.

2. The cathode lithium supplement material according to claim 1, characterized in that, The porous carrier includes one or more of: activated carbon, expanded graphite, activated carbon fiber, carbon nanotube, porous acetylene black, porous aluminum foam, porous nickel foam, porous alumina, porous zirconia, porous magnesia, porous silicon carbide, porous silicon nitride. The lithium supplement active substances include one or more mixtures of: lithium oxide, lithium oxalate, lithium acetate, lithium ferrite, lithium cuprate, lithium nickelate, lithium hydroxide.

3. The cathode lithium supplement material according to claim 1, characterized in that, The solid electrolyte includes one of: NASICON type solid electrolyte, perovskite type solid electrolyte, garnet type solid electrolyte or halide electrolyte.

4. The cathode lithium supplement material according to claim 3, characterized in that, The NASICON-type solid electrolyte specifically includes: Li 1+x A1 x A2 2+x (PO4)3, where x is between 0.01 and 0.5, A1 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and A2 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, and hafnium metal Hf; The perovskite-type solid electrolyte specifically includes: Li 3x A3 2 / 3-x A4O3, where x is between 0.01 and 0.5, A3 is one or more of La, Al, Mg, Fe, Ta, and A4 is one or more of Ti, Nb, Sr, Pr; The garnet-type solid electrolyte specifically includes: Li7A53A62O 12 , where A5 is one or more of La, Ca, Sr, Ba, and K, and A6 is one or more of Zr, Ta, Nb, and Hf; The halide electrolyte specifically includes Li 2+x-y ZrCl 6-x-y O x , where x ranges from 0 to 0.

6.

5. The cathode lithium supplement material according to claim 1, characterized in that, The mass ratio of the porous carrier to the lithium supplement active substances is 1:0.1 - 5; The mass ratio of the inner core to the outer shell is 1:0.02 - 0.

3.

6. The cathode lithium supplement material according to claim 1, characterized in that, The particle size of the porous carrier is 300 nm - 30 μm, and the specific surface area is 200 m 2 / g - 2000 m 2 / g; the outer core thickness of the solid electrolyte layer is 1 nm - 200 nm; the particle size of the cathode lithium supplement material is 1 nm - 150 μm.

7. A preparation method of the cathode lithium supplement material according to any one of claims 1-6, characterized in that, The preparation method includes: Weigh the lithium supplement active substances proportionally and dissolve them in the first solvent to obtain a mixed solution. Subsequently, add the porous carrier to the mixed solution and disperse for 6 h - 72 h to enable the lithium supplement active substances to adsorb into the pores of the porous carrier; dry the mixed solution to obtain the inner core material; Disperse the solid electrolyte material into the second solvent to make a slurry. Then add the slurry into the citric acid-ethylene glycol aqueous solution, and heat the solution to 70 °C - 150 °C to make the solution become a gel state, obtaining the coated layer solid electrolyte gel material; Add the inner core material into the coated layer solid electrolyte gel material and disperse evenly. Then dry to remove the solvent, transfer the obtained product to a heat treatment device and introduce an inert gas, calcine at 600 °C - 1300 °C for 1 h - 36 h, and after cooling to room temperature, the positive electrode lithium supplement material can be obtained.

8. The preparation method according to claim 7 above, characterized in that, The dispersion equipment includes one or more of: a disperser, a stirrer, a ball mill, an ultrasonic machine, a shaker; The heat treatment device includes one of: an atmosphere box furnace, a tube furnace, a rotary furnace, a pusher furnace; the inert gas is one or more of nitrogen, argon.

9. A cathode sheet, characterized in that, The positive electrode sheet includes the positive electrode lithium supplement material according to any one of claims 1 - 6 above.

10. A lithium ion battery, characterized in that, The lithium ion battery includes the positive electrode sheet according to claim 9 above.

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