A ternary precursor modified by a bio-based carbon material, and a preparation method and application thereof

Abstract

The application provides a kind of bio-based carbon material modified ternary precursor and its preparation method and application, the preparation method includes the following steps: (1) nickel cobalt manganese mixed salt solution, complexing agent, precipitant and doping metal source solution are injected into the bottom liquid for coprecipitation reaction, obtain the core solution;(2) adjust the solid content of core solution and the concentration of complexing agent, and flow injection nickel cobalt manganese mixed salt solution, complexing agent, precipitant and doping metal source solution, carry out the second coprecipitation reaction, obtain doped ternary precursor;(3) after carbonization of bio-based carbon source, mix with doped ternary precursor, sintering treatment obtains the bio-based carbon material modified ternary precursor.The doped element in the ternary precursor of the application effectively penetrates into the matrix for doping, the stability of the coating layer prepared by using bio-based carbon material is strong, and the rate characteristic is good.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, and relates to a ternary precursor modified with bio-based carbon materials, its preparation method and application. Background Technology

[0002] Advanced cathode materials with high specific capacity are urgently needed to meet the growing demand for high-energy-density lithium-ion batteries. Among numerous cathode candidates, Ni-rich (NCM) layered oxides can provide high capacities exceeding 200 mAh / g with an average discharge potential of 3.8 V (vsLi+ / Li). However, in practical applications, Ni-rich oxide cathode materials must overcome the problems of poor cycle stability and poor rate performance. These defects are largely attributed to the dense aggregation of their spherical micron-sized secondary particles by numerous randomly oriented primary particles. On the one hand, accompanied by this structure, the surface of the secondary particles is terminated by random crystal planes. Due to the presence of Li... + In the layered structure of NCM materials, diffusion is limited to the two-dimensional {010} plane. Randomly exposed crystal planes may severely hinder Li+ exchange at the electrode / electrolyte interface. Simultaneously, due to Li... + Ions need to cross grain boundaries, especially between grains with inconsistent crystal planes. Therefore, randomly oriented primary nanoparticles form a long Li-type rift within the secondary particles. + Diffusion pathway. On the other hand, accompanied by Li + Repeated intercalation and deintercalation, along with continuous phase transitions, lead to anisotropic changes in lattice parameters, which are exacerbated by increasing Ni content. Therefore, in nickel-rich oxide cathode materials, due to asynchronous volume changes, significant anisotropic lattice expansion / contraction results in drastic micro-strain at the boundaries of randomly oriented primary particles. Consequently, cracks may propagate and extend along grain boundaries until secondary particles develop cracks, or even primary particles detach. This is one of the main reasons for the rapid degradation of nickel-rich NCM materials during long-term cycling.

[0003] Current technological improvements typically employ doping and coating techniques to enhance the electrochemical performance of cathode materials. Surface coatings are primarily used to suppress side reactions between the cathode and electrolyte, while lattice ion doping is generally used to limit phase transitions during charge and discharge processes and stabilize the crystal structure.

[0004] CN118610403A discloses a zirconium-fluorine co-doped NCM-type high-nickel ternary cathode material. Zirconium replaces the transition metal sites and forms zirconium lithium oxide on the surface, while fluorine replaces the oxygen sites. This enhances the stability of the material's crystal structure and improves lithium-ion diffusion and surface reaction kinetics, thereby improving both the rate performance and cycle stability of the battery material.

[0005] CN118676350A discloses a modified cathode material that, through co-doping with K and Si, suppresses particle cracking during cycling, enhances the structural stability of the modified cathode material, and improves its rate performance and cycle performance.

[0006] CN118630174A describes a process where a pre-sintered ternary cathode material matrix is ​​mixed with a coating material containing La and then sintered again to form a coating layer on the surface of the ternary cathode material matrix. Rare earth elements from the coating material are then incorporated into the ternary cathode material matrix to obtain a ternary cathode material. The ternary cathode material of this application exhibits high structural stability, conductivity, capacity, and cycle stability.

[0007] However, traditional surface coating and lattice ion doping modification techniques cannot effectively solve the problem of layered particles in nickel-rich NCM materials. Given the hexagonal layered NCM material's Li... + The high anisotropy of diffusion and lattice expansion / contraction makes morphology modulation an effective method to improve the rate performance and cycling stability of NCM materials. However, the synthesis of NCM materials with superior rate and cycling performance through structure and morphology control remains a significant challenge. Summary of the Invention

[0008] The purpose of this invention is to provide a ternary precursor modified with bio-based carbon materials, its preparation method, and its application. This invention prepares a precursor with high sphericity by adjusting the conditions of the coprecipitation reaction through a two-step coprecipitation method. During the coprecipitation process, adding appropriate dopant elements can stabilize the crystal structure and improve the interlayer spacing of metal ions. Then, biomass carbon materials are coated on the surface of the precursor to improve the cycle stability of the precursor while achieving the goals of green environmental protection and cost reduction.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a ternary precursor modified with bio-based carbon materials, the preparation method comprising the following steps:

[0011] (1) The first nickel-cobalt-manganese mixed salt solution, the first complexing agent, the first precipitant and the first doped metal source solution are injected in parallel into the first bottom liquid to carry out the first coprecipitation reaction to obtain the core solution;

[0012] (2) Adjust the solid content of the core solution and the concentration of the first complexing agent to obtain the second bottom solution. Inject the second nickel-cobalt-manganese mixed salt solution, the second complexing agent, the second precipitant and the second doped metal source solution into the second bottom solution in parallel to carry out the second co-precipitation reaction to obtain the doped ternary precursor.

[0013] (3) Carbonize the bio-based carbon source to obtain a bio-based carbon coating material. Mix the bio-based carbon coating material with a doped ternary precursor and sinter to obtain the ternary precursor modified with the bio-based carbon material.

[0014] In this invention, the types of the first nickel-cobalt-manganese mixed salt solution and the second nickel-cobalt-manganese mixed salt solution, the types of the first complexing agent and the second complexing agent, the types of the first precipitant and the second precipitant, and the types of the first precipitant and the second precipitant are all the same. Here, "first" and "second" are only used to distinguish the addition steps.

[0015] This invention improves the uniformity and consistency of precursor growth and enhances the sphericity of the precursor through a two-step co-precipitation process. During the co-precipitation process, a doped metal source is added. The doped element can improve the safety of the electrode material in the electrochemical reaction process and the interlayer spacing of metal ions. Then, the obtained doped ternary precursor is mixed with biomass carbon source and sintered for coating. Biomass materials, as a new type of material in the low-carbon, environmentally friendly and economical field, have a wide range of material sources, are green and environmentally friendly, and can achieve large-scale mass production.

[0016] Preferably, in step (1), the molar ratio of the total molar amount of doped metal elements in the first doped metal source solution to the total molar amount of nickel, cobalt and manganese elements in the first nickel-cobalt-manganese mixed salt solution is (0.05-5):100, for example: 0.05:100, 0.1:100, 1:100, 2:100 or 5:100, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably (0.5-1.5):100.

[0017] Preferably, in step (1), the total mass concentration of nickel ions, cobalt ions and manganese ions in the first nickel-cobalt-manganese mixed salt solution is 20 g / L to 120 g / L, for example: 20 g / L, 50 g / L, 80 g / L, 100 g / L or 120 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, in step (1), the molar ratio of nickel ions, cobalt ions and manganese ions in the first nickel-cobalt-manganese mixed salt solution is (60-95):(1-20):(1-20), for example: 60:20:20, 65:18:17, 70:15:15, 80:10:10 or 95:2:3, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, in step (1), the first complexing agent comprises ammonia.

[0020] Preferably, the mass concentration of the first complexing agent in step (1) is 5% to 10%, for example: 5%, 6%, 8%, 9% or 10%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, in step (1), the first precipitant comprises a sodium hydroxide solution.

[0022] Preferably, in step (1), the mass concentration of the first precipitant is 20% to 40%, for example: 20%, 25%, 30%, 35% or 40%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, the doped metal source in the first doped metal source solution in step (1) includes any one or a combination of at least two of the following: aluminum source, titanium source, niobium source, zirconium source, tungsten source, vanadium source, strontium source, gallium source, cerium source, yttrium source, lanthanum source, or antimony source. Typical but non-limiting combinations include a combination of lanthanum source and antimony source, a combination of antimony source and strontium source, or a combination of antimony source and gallium source, etc., preferably an antimony source.

[0024] Preferably, the antimony source includes any one or a combination of at least two of antimony trichloride, sodium antimonate, potassium antimonate, potassium antimony tartrate, or sodium antimony tartrate. Typical but non-limiting combinations include combinations of potassium antimonate and potassium antimony tartrate, combinations of sodium antimonate and potassium antimonate, or combinations of antimony trichloride and sodium antimonate.

[0025] This invention uses antimony as a dopant element. Antimony diffuses into the crystal lattice, replacing some transition metal elements and forming more stable chemical bonds with oxygen. This stabilizes the crystal structure, suppresses Li-Ni mixing, and improves safety during electrochemical reactions. Simultaneously, it improves the interlayer spacing of metal ions, shortening the lithium-ion transport distance and enhancing the material's rate performance.

[0026] Preferably, in step (1), the mass concentration of the first doped metal source solution is 10 g / L to 50 g / L, for example: 1 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, in step (1), the first base liquid contains a first complexing agent and a first precipitant.

[0028] Preferably, the pH of the first base solution in step (1) is 10 to 11.5, for example: 10, 10.5, 10.8, 11 or 11.5, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] Preferably, in step (1), the concentration of the first complexing agent in the first base liquid is 4 g / L to 12 g / L, for example: 4 g / L, 5 g / L, 8 g / L, 10 g / L or 12 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the atmosphere for the first coprecipitation reaction in step (1) includes nitrogen.

[0031] Preferably, the temperature of the first coprecipitation reaction in step (1) is 40℃~60℃, for example: 40℃, 45℃, 50℃, 55℃ or 60℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] Preferably, in the first coprecipitation reaction in step (1), the flow rate of the first nickel-cobalt-manganese mixed salt solution is 2L / h to 4L / h, for example: 2L / h, 2.5L / h, 3L / h, 3.5L / h or 4L / h, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] Preferably, in step (1) during the first coprecipitation reaction, the mass concentration of the first complexing agent is 4 g / L to 8 g / L, for example: 4 g / L, 5 g / L, 6 g / L, 7 g / L or 8 g / L, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0034] Preferably, the pH of the first coprecipitation reaction in step (1) is 11.2 to 12.0, for example: 11.2, 11.5, 11.6, 11.8 or 12, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] Preferably, in the first coprecipitation reaction in step (1), the flow rate of the first doped metal source solution is 100 mL / h to 300 mL / h, for example: 100 mL / h, 150 mL / h, 200 mL / h, 250 mL / h or 300 mL / h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the median particle size D50 of the kernel particles in the kernel solution in step (1) is 3.5μm to 5μm, for example: 3.5μm, 3.8μm, 4μm, 4.5μm or 5μm, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the solid content of the second base liquid in step (2) is 100g / L to 500g / L, for example: 100g / L, 200g / L, 300g / L, 400g / L or 500g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, in step (2), the concentration of the first complexing agent in the second base liquid is 2 g / L to 8 g / L, for example: 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L or 6 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the pH of the second base solution in step (2) is 10 to 12, for example: 10, 10.5, 11, 11.5 or 12, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0040] Preferably, in step (2), the molar ratio of the total molar amount of doped metal elements in the second doped metal source solution to the total molar amount of nickel, cobalt and manganese elements in the second nickel-cobalt-manganese mixed salt solution is (0.05-5):100, for example: 0.05:100, 0.1:100, 1:100, 2:100 or 5:100, etc., not limited to the listed values, other unlisted values ​​within this range are also applicable, preferably (0.5-1.5):100.

[0041] Preferably, in step (2), the total mass concentration of nickel ions, cobalt ions and manganese ions in the second nickel-cobalt-manganese mixed salt solution is 20 g / L to 120 g / L, for example: 20 g / L, 50 g / L, 80 g / L, 100 g / L or 120 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, in step (2), the molar ratio of nickel ions, cobalt ions and manganese ions in the second nickel-cobalt-manganese mixed salt solution is (60-95):(1-20):(1-20), for example: 60:20:20, 65:18:17, 70:15:15, 80:10:10 or 95:2:3, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, in step (2), the second complexing agent comprises ammonia.

[0044] Preferably, the mass concentration of the second complexing agent in step (2) is 5% to 10%, for example: 5%, 6%, 8%, 9% or 10%, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0045] Preferably, in step (2), the second precipitant comprises a sodium hydroxide solution.

[0046] Preferably, in step (2), the mass concentration of the second precipitant is 20% to 40%, for example: 20%, 25%, 30%, 35% or 40%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] Preferably, the doped metal source in the second doped metal source solution in step (2) includes any one or a combination of at least two of sodium source, calcium source, niobium source, molybdenum source, tungsten source, zirconium source or antimony source. Typical but non-limiting combinations include combinations of sodium source and antimony source, combinations of antimony source and zirconium source or combinations of antimony source and tungsten source, etc., with antimony source being preferred.

[0048] Preferably, the antimony source includes any one or a combination of at least two of antimony trichloride, sodium antimonate, potassium antimonate, potassium antimony tartrate, or sodium antimony tartrate. Typical but non-limiting combinations include combinations of potassium antimonate and potassium antimony tartrate, combinations of sodium antimonate and potassium antimonate, or combinations of antimony trichloride and sodium antimonate.

[0049] Preferably, in step (2), the mass concentration of the second doped metal source solution is 10 g / L to 50 g / L, for example: 1 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0050] Preferably, the atmosphere for the second coprecipitation reaction in step (2) includes nitrogen.

[0051] Preferably, the temperature of the second coprecipitation reaction in step (2) is 40℃~60℃, for example: 40℃, 45℃, 50℃, 55℃ or 60℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0052] Preferably, in step (2), during the second coprecipitation reaction, the flow rate of the second nickel-cobalt-manganese mixed salt solution is 4 L / h to 6 L / h, for example: 4 L / h, 4.5 L / h, 5 L / h, 5.5 L / h or 6 L / h, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] Preferably, in step (2), during the second coprecipitation reaction, the concentration of the second complexing agent is 4 g / L to 8 g / L, for example: 4 g / L, 5 g / L, 6 g / L, 7 g / L or 8 g / L, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0054] Preferably, the pH of the second coprecipitation reaction in step (2) is 11 to 13, for example: 11, 11.5, 12, 12.5 or 13, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0055] Preferably, in step (2), during the second coprecipitation reaction, the flow rate of the second doped metal source solution is 200 mL / h to 1000 mL / h, for example: 200 mL / h, 400 mL / h, 600 mL / h, 800 mL / h or 1000 mL / h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] Preferably, during the second coprecipitation reaction in step (2), for every 1 μm to 3 μm increase in the median particle size D50 of the particles in the system, for example: 1 μm, 1.5 μm, 2 μm, 2.5 μm or 3 μm, etc., not limited to the listed values, other unlisted values ​​within this range are also applicable. The flow rates of the second nickel-cobalt-manganese mixed salt solution, the second complexing agent, the second precipitant and the second doped metal source solution are independently increased by 10% to 30%, for example: 10%, 15%, 20%, 25% or 30%, etc., not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0057] In the second coprecipitation reaction of the present invention, the flow rates of complexing agent, precipitant, ternary liquid and doped metal salt solution are increased correspondingly for every 1 to 3 μm increase in median particle size D50 in the system to maintain a constant growth rate. The feeding reaction is stopped when the grown particle size reaches the target value.

[0058] Preferably, after the second coprecipitation reaction in step (2), the product is aged, washed and dried.

[0059] Preferably, the bio-based carbon source in step (3) includes any one or a combination of at least two of peanut shells, rice shells, mangosteen shells, coconut shells, corn stalks or walnut septum, with peanut shells being the most preferred.

[0060] Preferably, the bio-based carbon source is pretreated with acidification before the carbonization process in step (3).

[0061] Preferably, the acidification pretreatment includes immersing a bio-based carbon source in an acid solution.

[0062] Preferably, the acid solution comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, or nitric acid.

[0063] Preferably, the mass concentration of the acid solution is 10% to 30%, for example: 10%, 15%, 20%, 25% or 30%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0064] Preferably, the soaking temperature is 50℃~80℃, for example: 50℃, 55℃, 60℃, 70℃ or 80℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0065] Preferably, the soaking time is 60 min to 100 min, for example: 600 min, 700 min, 800 min, 900 min or 1000 min, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0066] Preferably, the carbonization temperature in step (3) is 400℃~800℃, for example: 400℃, 500℃, 600℃, 700℃ or 800℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0067] Preferably, the carbonization time in step (3) is 100 min to 800 min, for example: 100 min, 200 min, 300 min, 500 min or 800 min, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0068] Preferably, the carbonization process described in step (3) is followed by drying.

[0069] Preferably, the drying temperature is 80℃~150℃, for example: 80℃, 90℃, 100℃, 120℃ or 150℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0070] Preferably, the mass ratio of the bio-based carbon coating material to the doped ternary precursor in step (3) is (1-10):(50-200), for example: 1:50, 2:50, 5:100, 8:20 or 10:200, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably (1-5):(50-100).

[0071] Preferably, the sintering process in step (3) includes a first sintering and a second sintering.

[0072] Preferably, the temperature of the first sintering is 400℃ to 700℃, for example: 400℃, 450℃, 500℃, 600℃ or 700℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] Preferably, the first sintering time is 3h to 6h, for example: 3h, 3.5h, 4h, 5h or 6h, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0074] Preferably, the second sintering temperature is 700℃~1000℃, for example: 7000℃, 7500℃, 8000℃, 9000℃ or 10000℃, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0075] Preferably, the second sintering time is 10h to 20h, for example: 10h, 12h, 15h, 18h or 20h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0076] In a second aspect, the present invention provides a ternary precursor modified with bio-based carbon materials, wherein the ternary precursor modified with bio-based carbon materials is prepared by the preparation method described in the first aspect.

[0077] Thirdly, the present invention provides a ternary cathode material modified with bio-based carbon materials, wherein the ternary cathode material modified with bio-based carbon materials is prepared by mixing and sintering a ternary precursor modified with bio-based carbon materials as described in the second aspect with a lithium source.

[0078] Preferably, the lithium source includes lithium hydroxide and / or lithium carbonate.

[0079] Fourthly, the present invention provides a lithium-ion battery comprising a ternary cathode material modified with bio-based carbon material as described in the third aspect.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] (1) This invention prepares a high-sphericity precursor by adjusting the conditions of the coprecipitation reaction through a two-step coprecipitation method. During the coprecipitation process, adding appropriate dopant elements can stabilize the crystal structure and improve the interlayer spacing of metal ions. Then, biomass carbon materials are coated on the surface of the precursor to improve the cycle stability of the precursor while achieving the purpose of green environmental protection and reducing costs.

[0082] (2) The lithium-ion battery prepared by the method of the present invention can achieve an initial discharge capacity of more than 203.4 mAh / g, an initial coulombic efficiency of more than 89.6%, and a capacity retention rate of more than 87.2% after 100 cycles. Attached Figure Description

[0083] Figure 1 This is a surface SEM image of the ternary precursor modified with bio-based carbon materials obtained in Example 1 of this invention.

[0084] Figure 2 This is a cross-sectional SEM image of the ternary precursor modified with bio-based carbon materials obtained in Example 1 of this invention. Detailed Implementation

[0085] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0086] Example 1

[0087] This embodiment provides a ternary precursor modified with bio-based carbon materials, which is prepared by the following method:

[0088] (1) Prepare a nickel-cobalt-manganese mixed salt solution with a total metal element concentration of 80 g / L and a Ni, Co, and Mn molar ratio of 94:3:3, a 25% NaOH solution, and a 7.5% ammonia solution. Prepare a 20 g / L antimony trichloride solution, wherein the molar ratio of antimony in the antimony trichloride solution to the total molar ratio of nickel, cobalt, and manganese in the nickel-cobalt-manganese mixed salt solution is 1:100. Add 150 L of pure water and a certain amount of NaOH solution and ammonia solution to a 300 L reactor, and stir at a flow rate of 0.8 m 3 Nitrogen gas is introduced into the base solution at a rate of / h, and the mixture is stirred at 200 rpm to ensure uniform mixing. The temperature is then raised to 40℃, and the pH is controlled at 11-11.5. The ammonia concentration is controlled at 6 g / L to 8 g / L to obtain the base solution. At 60℃, a nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia water, and antimony trichloride solution are introduced into the base solution in parallel. The flow rate of the nickel-cobalt-manganese mixed salt solution is 4 L / h, the flow rate of the antimony trichloride solution is 200 mL / h, the ammonia concentration is 6 g / L to 8 g / L, and the pH is 11.2 to 11.5. When the internal nucleation is completed and the growth reaches 4.5 μm, the feeding reaction is stopped to obtain the core solution.

[0089] (2) Take 100L of the core solution and transfer it to another 300L capacity reactor. Add 100L of water to control the solid content to 300g / L, and add ammonia to control the ammonia concentration in the reaction system to be within the range of 4-6g / L and the pH to be 11-11.2, to obtain the bottom solution. At 60℃, introduce nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia and antimony trichloride solution in a parallel flow into the bottom solution. The flow rate of the nickel-cobalt-manganese mixed salt solution is 6L / h, the ammonia concentration is 6g / L-7g / L, the pH is 11.5-11.8, and the flow rate of the antimony trichloride solution is 500mL / h. When the particle size grows to 7μm in the reaction, increase the flow rate of the nickel-cobalt-manganese mixed salt solution to 8L / h, and the ammonia... The flow rates of water, sodium hydroxide solution, and antimony trichloride solution were 1000 mL / L, 2.5 L / h, and 650 mL / h, respectively. When the particle size grew to 9.5 μm, the flow rates of nickel-cobalt-manganese mixed salt solution, ammonia, sodium hydroxide solution, and antimony trichloride solution were increased to 10 L / h, 1200 mL / L, 3 L / h, and 800 mL / h, respectively, to maintain a constant growth rate. The feeding reaction was stopped when the particle size reached 12 μm. The obtained qualified slurry was washed and dried. The washing was performed four times with water, and the drying was carried out at a low temperature of 120°C to finally form a doped and modified ternary precursor with high sphericity.

[0090] (3) The peanut shells were crushed and ground, and then sieved. The peanut shell powder was soaked and dissolved in a 20% hydrochloric acid solution at a temperature of 80°C for 100 min. The powder was then washed twice and calcined in a high-temperature furnace at a temperature of 800°C for 600 min. The carbonized product was washed three times and dried in a 100°C oven to obtain bio-based carbon material. The mass ratio of the doped and modified high-sphericity ternary precursor to the bio-based carbon material was 100:1. The mixture was sintered in a box furnace at a temperature of 600°C for 4 h in the first stage and at a temperature of 950°C for 10 h in the second stage to obtain the modified ternary precursor of the bio-based carbon material.

[0091] The surface SEM image of the bio-based carbon material modified ternary precursor is shown below. Figure 1 As shown, by Figure 1 It can be seen that the primary particles of the ternary precursors modified with bio-based carbon materials exhibit a needle-like morphology.

[0092] The cross-sectional SEM image of the bio-based carbon material modified ternary precursor is shown below. Figure 2 As shown, by Figure 2 It can be seen that the bio-based carbon-modified ternary precursor has a very obvious core structure, while the particle growth exhibits a radial morphology. This radial morphology forms a straight Li...+ The transport channel is beneficial for Li in subsequent electrochemical cycles. + The insertion and extraction of materials improves their rate performance.

[0093] Example 2

[0094] This embodiment provides a ternary precursor modified with bio-based carbon materials, which is prepared by the following method:

[0095] (1) Prepare a nickel-cobalt-manganese mixed salt solution with a total metal element concentration of 80 g / L and a Ni, Co, and Mn molar ratio of 94:3:3, a 25% NaOH solution, and a 7.5% ammonia solution. Prepare a 20 g / L antimony trichloride solution, wherein the molar ratio of antimony in the antimony trichloride solution to the total molar ratio of nickel, cobalt, and manganese in the nickel-cobalt-manganese mixed salt solution is 1.5:100. Add 150 L of pure water and a certain amount of NaOH solution and ammonia solution to a 300 L reactor, and stir at a flow rate of 0.8 m 3 Nitrogen gas is introduced into the base solution at a rate of / h, and the mixture is stirred at 200 rpm to ensure uniform mixing. The temperature is then raised to 50℃, and the pH is controlled at 10.5-11. The ammonia concentration is controlled at 6 g / L-8 g / L to obtain the base solution. At 55℃, a nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia water, and antimony trichloride solution are introduced into the base solution in a parallel flow. The flow rate of the nickel-cobalt-manganese mixed salt solution is 3 L / h, the ammonia concentration is 7 g / L-8 g / L, the pH is 11.5-11.8, and the flow rate of the antimony trichloride solution is 150 mL / h. When the internal nucleation is completed and the growth reaches 5 μm, the feeding reaction is stopped to obtain the core solution.

[0096] (2) Take 100L of the core solution and transfer it to another 300L capacity reactor. Add 100L of water to control the solid content to 500g / L, and add ammonia water to control the ammonia concentration in the reaction system to be within the range of 2-4g / L and the pH to be 11-11.3 to obtain the bottom solution. At 50℃, introduce nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia water and antimony trichloride solution in a parallel flow into the bottom solution. The flow rate of the nickel-cobalt-manganese mixed salt solution is 4L / h, the ammonia concentration is 6g / L-8g / L, the pH is 11.2-11.5, and the flow rate of the antimony trichloride solution is 300mL / h. When the particle size grows to 7.5μm in the reaction, increase the flow rate of the nickel-cobalt-manganese mixed salt solution to 5L / h. The flow rates of ammonia solution, sodium hydroxide solution, and antimony trichloride solution were 900 mL / L, 2.2 L / h, and 350 mL / h, respectively. When the particle size grew to 10 μm, the flow rates of nickel-cobalt-manganese mixed salt solution, ammonia solution, sodium hydroxide solution, and antimony trichloride solution were increased to 6 L / h, 1080 mL / L, 2.5 L / h, and 420 mL / h, respectively, to maintain a constant growth rate. The feeding reaction was stopped when the particle size reached 12.5 μm. The obtained qualified slurry was washed and dried. The washing was performed four times with water, and the drying was carried out at a low temperature of 120 °C, finally forming a doped and modified ternary precursor with high sphericity.

[0097] (3) The peanut shells were crushed and ground, and then sieved. The peanut shell powder was soaked and dissolved in a 30% hydrochloric acid solution at a temperature of 50°C for 60 minutes. The powder was then washed twice with water and calcined in a high-temperature furnace at a temperature of 500°C for 800 minutes. The carbonized product was washed three times with water and dried in a 100°C oven to obtain bio-based carbon material. The mass ratio of the doped and modified high-sphericity ternary precursor to the bio-based carbon material was 100:5. The mixture was sintered in a box furnace at a temperature of 500°C for 5.5 hours and at a temperature of 800°C for 15 hours to obtain the modified ternary precursor of the bio-based carbon material.

[0098] Example 3

[0099] This embodiment provides a ternary precursor modified with bio-based carbon materials, which is prepared by the following method:

[0100] (1) Prepare a nickel-cobalt-manganese mixed salt solution with a total metal element concentration of 80 g / L and a Ni, Co, and Mn molar ratio of 94:3:3, a 25% NaOH solution, and a 7.5% ammonia solution. Prepare a 20 g / L antimony trichloride solution, wherein the molar ratio of antimony in the antimony trichloride solution to the total molar ratio of nickel, cobalt, and manganese in the nickel-cobalt-manganese mixed salt solution is 0.5:100. Add 150 L of pure water and a certain amount of NaOH solution and ammonia solution to a 300 L reactor, and stir at a flow rate of 0.8 m 3 Nitrogen gas is introduced into the base solution at a rate of 1 / h, and the mixture is stirred at 200 rpm to ensure uniform mixing. The temperature is then raised to 50℃, and the pH is controlled at 10.8-11.2, while the ammonia concentration is controlled at 8 g / L-9 g / L to obtain the base solution. At 50℃, a nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia water, and antimony trichloride solution are introduced into the base solution in a parallel flow. The flow rate of the nickel-cobalt-manganese mixed salt solution is 3 L / h, the ammonia concentration is 7 g / L-8 g / L, the pH is 11.2-11.5, and the flow rate of the antimony trichloride solution is 150 mL / h. When the internal nucleation is completed and the growth reaches 5 μm, the feeding reaction is stopped to obtain the core solution.

[0101] (2) Take 100L of the core solution and transfer it to another 300L capacity reactor. Add 100L of water to control the solid content to 100g / L, and add ammonia water to control the ammonia concentration in the reaction system to be in the range of 6-8g / L and the pH to be 11-11.3 to obtain the bottom solution. At 50℃, introduce nickel-cobalt-manganese mixed salt solution, NaOH solution, ammonia water and antimony trichloride solution in a parallel flow into the bottom solution. The flow rate of the nickel-cobalt-manganese mixed salt solution is 6L / h, the ammonia concentration is 6g / L-7g / L, the pH is 11.5-11.8, and the flow rate of the antimony trichloride solution is 400mL / h. When the particle size grows to 7μm in the reaction, increase the flow rate of the nickel-cobalt-manganese mixed salt solution to 6.6L / h. The flow rates of ammonia solution, sodium hydroxide solution, and antimony trichloride solution were 1100 mL / L, 2.2 L / h, and 450 mL / h, respectively. When the particle size grew to 9 μm, the flow rates of nickel-cobalt-manganese mixed salt solution, ammonia solution, sodium hydroxide solution, and antimony trichloride solution were increased to 7.3 L / h, 1320 mL / L, 2.5 L / h, and 500 mL / h, respectively, to maintain a constant growth rate. The feeding reaction was stopped when the particle size reached 12 μm. The obtained qualified slurry was washed and dried. The washing was performed four times with water, and the drying was carried out at a low temperature of 120°C, ultimately forming a doped and modified ternary precursor with high sphericity.

[0102] (3) The peanut shells were crushed and ground, and then sieved. The peanut shell powder was soaked and dissolved in a 20% hydrochloric acid solution at a temperature of 50°C for 80 minutes. The powder was then washed twice with water and calcined in a high-temperature furnace at a temperature of 600°C for 600 minutes. The carbonized product was washed three times with water and dried in a 100°C oven to obtain bio-based carbon material. The mass ratio of the doped and modified high-sphericity ternary precursor to the bio-based carbon material was 50:1. The mixture was sintered in a box furnace at a temperature of 400°C for 6 hours in the first stage and at a temperature of 700°C for 20 hours in the second stage to obtain the modified ternary precursor of the bio-based carbon material.

[0103] Example 4

[0104] The only difference between this embodiment and Example 1 is that the ratio of the molar amount of antimony in the antimony trichloride solution to the total molar amount of nickel, cobalt and manganese in the nickel-cobalt-manganese mixed salt solution is 0.1:100. All other conditions and parameters are exactly the same as in Example 1.

[0105] Example 5

[0106] The only difference between this embodiment and Example 1 is that the ratio of the molar amount of antimony in the antimony trichloride solution to the total molar amount of nickel, cobalt and manganese in the nickel-cobalt-manganese mixed salt solution is 2:100. All other conditions and parameters are exactly the same as in Example 1.

[0107] Example 6

[0108] The only difference between this embodiment and Embodiment 1 is that the peanut shells are replaced with rice shells; all other conditions and parameters are exactly the same as in Embodiment 1.

[0109] Example 7

[0110] The only difference between this embodiment and Embodiment 1 is that the peanut shells are replaced with corn stalks; all other conditions and parameters are exactly the same as in Embodiment 1.

[0111] Example 8

[0112] The only difference between this embodiment and Embodiment 1 is that the mass ratio of the doped and modified high sphericity ternary precursor to the bio-based carbon material is 8:50. All other conditions and parameters are exactly the same as in Embodiment 1.

[0113] Example 9

[0114] The only difference between this embodiment and Embodiment 1 is that the mass ratio of the doped and modified high sphericity ternary precursor to the bio-based carbon material is 150:1. All other conditions and parameters are exactly the same as in Embodiment 1.

[0115] Example 10

[0116] The only difference between this embodiment and embodiment 1 is that the flow rate of the nickel-cobalt-manganese mixed salt solution in step (2) is 6 L / h, the flow rate of ammonia is 1000 ml / L, the flow rate of sodium hydroxide solution is 2 L / h, and the flow rate of antimony trichloride solution is 400 mL / h, which remains unchanged until the particle size reaches 12 μm. Other conditions and parameters are exactly the same as in embodiment 1.

[0117] Comparative Example 1

[0118] The only difference between this comparative example and Example 1 is that antimony chloride solution is not added; all other conditions and parameters are exactly the same as in Example 1.

[0119] Comparative Example 2

[0120] The only difference between this comparative example and Example 1 is that the doped ternary precursor is prepared directly using a one-step co-precipitation method; all other conditions and parameters are exactly the same as in Example 1.

[0121] Example 3

[0122] The only difference between this comparative example and Example 1 is that step (3) is omitted; all other conditions and parameters are exactly the same as in Example 1.

[0123] Comparative Example 4

[0124] In this comparative example, peanut shells were replaced with carbon nanotubes. The preparation method is as follows: After activating the multi-walled carbon nanotubes, a suspension containing carbon nanotubes with a concentration of 5 g / L was obtained. The doped and modified high sphericity ternary precursor prepared in step (2) of Example 1 was added, stirred, and sonicated at 1.0 kW for 30 min. After filtration and washing with water five times, the precursor was dried in an oven at 100 ℃ to obtain the carbon nanotube-coated doped precursor.

[0125] Performance testing:

[0126] The ternary precursors prepared in the examples and comparative examples were mixed with lithium hydroxide at a ratio of Li:(Ni+Co+Mn)=1:1 and sintered at 500℃ for 5h and 750℃ for 20h to obtain a ternary cathode material. The ternary cathode material was used as the cathode active material and mixed with conductive carbon and PVDF at a ratio of 94:3:3. The mixture was then dispersed in methylpyrrolidone (NMP) as a solvent to obtain a cathode slurry, which was uniformly coated on aluminum foil. After coating, the current collector was perforated to obtain a coin-shaped electrode. After vacuum drying at 120℃ overnight, a cathode sheet was obtained. The anode was made of lithium metal. 1MLiPF6 was dissolved in EC and DMC solvent (volume ratio 3:7) as the electrolyte. The cathode, anode, and separator were wound to prepare a battery cell, which was then packaged, injected with electrolyte, formed, and capacity tested to assemble a lithium-ion battery.

[0127] The prepared lithium-ion battery was subjected to electrochemical performance testing at 0.1C, with a voltage of 3.0-4.4 V (vsLi / Li). + CR2032 coin-type half-cells were cycled between cycles. The initial discharge capacity and initial efficiency, as well as the discharge capacity at the 100th cycle, were measured to obtain the capacity retention rate after 100 cycles. The test results are shown in Table 1.

[0128] Table 1

[0129] Initial discharge capacity (mAh / g) First-time coulomb efficiency (%) Capacity retention rate (%) Example 1 218.2 95.4 91.5 Example 2 211.2 92.4 89.8 Example 3 209.7 91.8 89.6 Example 4 206.9 90.9 89.1 Example 5 203.4 89.6 87.2 Example 6 210.2 93.5 90.7 Example 7 208.4 92.9 90.4 Example 8 212.5 93.1 90.3 Example 9 210.7 93.4 91.0 Example 10 204.5 90.1 87.7 Comparative Example 1 198.3 87.5 86.1 Comparative Example 2 196.8 86.8 85.9 Comparative Example 3 201.6 88.7 86.8 Comparative Example 4 207.7 91.2 89.5

[0130] As can be seen from Table 1, as obtained from Examples 1-10, the lithium-ion battery made from the ternary precursor prepared by the method of the present invention can achieve an initial discharge capacity of over 203.4 mAh / g, an initial coulombic efficiency of over 89.6%, and a capacity retention rate of over 87.2% after 100 cycles.

[0131] Comparing Examples 1 and 4-5, it can be seen that during the preparation of the ternary precursor modified with bio-based carbon materials according to the present invention, the molar ratio between the dopant metal in the doped metal source solution and the nickel-cobalt-manganese in the nickel-cobalt-manganese mixed salt solution affects its performance. Controlling the molar ratio of the dopant metal to nickel-cobalt-manganese at (0.5-1.5):100 yields a ternary precursor modified with bio-based carbon materials with better performance. If the amount of dopant metal added is too large, more transition metal ion sites will be occupied, which will limit the discharge capacity of the material. At the same time, the lattice distortion effect will also deteriorate the electrochemical performance. If the amount of dopant metal added is too small, the improvement of the interlayer spacing of transition metal ions is limited, and it will not play a doping role.

[0132] A comparison of Examples 1 and 6-7 shows that during the preparation of the ternary precursor modified with bio-based carbon materials according to the present invention, the weight of the bio-carbon material affects its performance. Using peanut shells as bio-carbon materials significantly improves the performance of the ternary precursor.

[0133] A comparison of Examples 1 and 8-9 shows that during the preparation of the bio-based carbon material modified ternary precursor of the present invention, the mass ratio of the doped modified high sphericity ternary precursor to the bio-based carbon material affects its performance. Controlling the mass ratio of the doped modified high sphericity ternary precursor to the bio-based carbon material at (1-5):(50-100) yields a bio-based carbon material modified ternary precursor with better performance. If the amount of bio-based carbon material added is too large, the carbon protective layer formed on the material surface will be too thick, which is not conducive to the transport of lithium ions. At the same time, if the amount of bio-based carbon material added is too small, the protective effect of the carbon protective layer is limited, and the electrolyte can easily penetrate into the material during cycling, resulting in deterioration of cycling performance.

[0134] A comparison of Examples 1 and 10 shows that, in the second coprecipitation reaction of the present invention, for every 1-3 μm increase in the median particle size D50 in the system, the flow rates of the complexing agent, precipitant, ternary liquid, and doped metal salt solution are correspondingly increased to maintain a constant growth rate, thereby significantly improving the performance of the obtained ternary precursor.

[0135] As can be seen from the comparison between Example 1 and Comparative Example 1, the present invention uses antimony as a dopant element. Antimony diffuses into the crystal lattice, replacing some transition metal elements and forming more stable chemical bonds with oxygen, thus stabilizing the crystal structure, suppressing Li-Ni mixing, and improving safety during electrochemical reactions. Simultaneously, it can improve the interlayer spacing of metal ions, shortening the lithium-ion transport distance and improving the rate performance of the material.

[0136] As can be seen from the comparison between Example 1 and Comparative Example 2, the present invention can significantly improve the uniformity and consistency of precursor growth and improve the sphericity of the precursor by preparing ternary precursors through a two-step co-precipitation method.

[0137] As can be seen from the comparison between Example 1 and Comparative Examples 3-4, the ternary precursor of the present invention can obtain ternary cathode materials that are no worse than those coated with carbon materials such as carbon nanotubes by using environmentally friendly biomass carbon materials as coating agents. It is not only green and environmentally friendly, but also significantly reduces costs.

[0138] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a ternary precursor modified with bio-based carbon materials, characterized in that, The preparation method includes the following steps: (1) The first nickel-cobalt-manganese mixed salt solution, the first complexing agent, the first precipitant and the first doped metal source solution are injected in parallel into the first bottom liquid to carry out the first coprecipitation reaction to obtain the core solution; The mass concentration of the first complexing agent is 5%~10%; the mass concentration of the first precipitant is 20g / L~40g / L; the mass concentration of the first doped metal source solution is 10g / L~50g / L; the pH of the first base solution is 10~11.5; and the concentration of the first complexing agent in the first base solution is 4g / L~12g / L. The temperature of the first coprecipitation reaction is 40℃~60℃; during the first coprecipitation reaction, the flow rate of the first nickel-cobalt-manganese mixed salt solution is 2L / h~4L / h, the mass concentration of the first complexing agent is 4g / L~8g / L, and the pH of the first coprecipitation reaction is 11.2~12.0; during the first coprecipitation reaction, the flow rate of the first doped metal source solution is 100mL / h~300mL / h. (2) Adjust the solid content of the core solution and the concentration of the first complexing agent to obtain the second bottom solution. Inject the second nickel-cobalt-manganese mixed salt solution, the second complexing agent, the second precipitant and the second doped metal source solution into the second bottom solution in parallel to carry out the second co-precipitation reaction to obtain the doped ternary precursor. The concentration of the first complexing agent in the second base solution is 2 g / L to 8 g / L; the pH of the second base solution is 10 to 12; the total mass concentration of nickel ions, cobalt ions, and manganese ions in the second nickel-cobalt-manganese mixed salt solution is 20 g / L to 120 g / L; the mass concentration of the second complexing agent is 5% to 10%; the mass concentration of the second precipitant is 20% to 40%; and the mass concentration of the second doped metal source solution is 10 g / L to 50 g / L. The temperature of the second coprecipitation reaction is 40℃~60℃; during the second coprecipitation reaction, the flow rate of the second nickel-cobalt-manganese mixed salt solution is 4L / h~6L / h, and the concentration of the second complexing agent is 4g / L~8g / L; the pH of the second coprecipitation reaction is 11~13; during the second coprecipitation reaction, the flow rate of the second doped metal source solution is 200mL / h~1000mL / h; (3) Carbonize the bio-based carbon source to obtain a bio-based carbon coating material, mix the bio-based carbon coating material with the doped ternary precursor, and sinter to obtain the ternary precursor modified by the bio-based carbon material; the bio-based carbon source is peanut shell; the mass ratio of the bio-based carbon coating material to the doped ternary precursor is (1~10):(50~200); Step (1) The doping metal source in the first doped metal source solution is an antimony source, and the molar ratio of the total molar amount of the doped metal element to the total molar amount of nickel, cobalt and manganese elements in the first nickel-cobalt-manganese mixed salt solution is (0.5~1.5):100; Step (2) The doping metal source in the second doped metal source solution is an antimony source, and the molar ratio of the total molar amount of the doped metal element to the total molar amount of nickel, cobalt and manganese elements in the second nickel-cobalt-manganese mixed salt solution is (0.5~1.5):

100.

2. The preparation method according to claim 1, characterized in that, Step (1) The total mass concentration of nickel ions, cobalt ions and manganese ions in the first nickel-cobalt-manganese mixed salt solution is 20 g / L to 120 g / L.

3. The preparation method according to claim 1, characterized in that, Step (1) The molar ratio of nickel ions, cobalt ions and manganese ions in the first nickel-cobalt-manganese mixed salt solution is (60~95):(1~20):(1~20).

4. The preparation method according to claim 1, characterized in that, Step (1) The first complexing agent is ammonia.

5. The preparation method according to claim 1, characterized in that, Step (1) The first precipitant is a sodium hydroxide solution.

6. The preparation method according to claim 1, characterized in that, The antimony source includes any one or a combination of at least two of antimony trichloride, sodium antimonate, potassium antimonate, potassium antimony tartrate, or sodium antimony tartrate.

7. The preparation method according to claim 1, characterized in that, Step (1) The first base liquid contains a first complexing agent and a first precipitant.

8. The preparation method according to claim 1, characterized in that, In step (1), the atmosphere for the first coprecipitation reaction is nitrogen.

9. The preparation method according to claim 1, characterized in that, The median particle size D50 of the kernel particles in the kernel solution in step (1) is 3.5 μm to 5 μm.

10. The preparation method according to claim 1, characterized in that, Step (2) The solid content of the second base liquid is 100g / L~500g / L.

11. The preparation method according to claim 1, characterized in that, In step (2), the molar ratio of nickel ions, cobalt ions and manganese ions in the second nickel-cobalt-manganese mixed salt solution is (60~95):(1~20):(1~20).

12. The preparation method according to claim 1, characterized in that, Step (2) The second complexing agent is ammonia.

13. The preparation method according to claim 1, characterized in that, Step (2) The second precipitant is a sodium hydroxide solution.

14. The preparation method according to claim 1, characterized in that, The antimony source includes any one or a combination of at least two of antimony trichloride, sodium antimonate, potassium antimonate, potassium antimony tartrate, or sodium antimony tartrate.

15. The preparation method according to claim 1, characterized in that, In step (2), the atmosphere for the second coprecipitation reaction is nitrogen.

16. The preparation method according to claim 1, characterized in that, In step (2), during the second coprecipitation reaction, for every 1 μm to 3 μm increase in the median particle size D50 of the particles in the system, the flow rates of the second nickel-cobalt-manganese mixed salt solution, the second complexing agent, the second precipitant, and the second doped metal source solution independently increase by 10% to 30%.

17. The preparation method according to claim 1, characterized in that, Step (2) After the second coprecipitation reaction, the product is aged, washed and dried.

18. The preparation method according to claim 1, characterized in that, In step (3), the bio-based carbon source is pretreated by acidification before carbonization.

19. The preparation method according to claim 18, characterized in that, The acidification pretreatment includes immersing a bio-based carbon source in an acid solution.

20. The preparation method according to claim 19, characterized in that, The acid solution includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, or nitric acid.

21. The preparation method according to claim 19, characterized in that, The mass concentration of the acid solution is 10% to 30%.

22. The preparation method according to claim 19, characterized in that, The soaking temperature is 50℃~80℃.

23. The preparation method according to claim 19, characterized in that, The soaking time is 60 min to 100 min.

24. The preparation method according to claim 1, characterized in that, The carbonization temperature in step (3) is 400℃~800℃.

25. The preparation method according to claim 1, characterized in that, The carbonization process in step (3) takes 100 min to 800 min.

26. The preparation method according to claim 1, characterized in that, After carbonization in step (3), the material is dried.

27. The preparation method according to claim 26, characterized in that, The drying temperature is 80℃~150℃.

28. The preparation method according to claim 1, characterized in that, The mass ratio of the bio-based carbon coating material to the doped ternary precursor in step (3) is (1~5):(50~100).

29. The preparation method according to claim 1, characterized in that, The sintering process in step (3) includes a first sintering and a second sintering.

30. The preparation method according to claim 29, characterized in that, The first sintering temperature is 400℃~700℃.

31. The preparation method according to claim 29, characterized in that, The first sintering time is 3h~6h.

32. The preparation method according to claim 29, characterized in that, The second sintering temperature is 700℃~1000℃.

33. The preparation method according to claim 29, characterized in that, The second sintering time is 10h~20h.

34. A ternary precursor modified with bio-based carbon materials, characterized in that, The bio-based carbon material modified ternary precursor is prepared by the preparation method described in any one of claims 1-33.

35. A ternary cathode material modified with bio-based carbon materials, characterized in that, The bio-based carbon material modified ternary cathode material is prepared by mixing and sintering the bio-based carbon material modified ternary precursor as described in claim 34 with a lithium source.

36. A lithium-ion battery, characterized in that, The lithium-ion battery comprises a ternary cathode material modified with bio-based carbon material as described in claim 35.

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