Titanium carbide modified high-nickel ternary material, preparation method and battery

Abstract

This invention relates to a titanium carbide-modified high-nickel ternary material, its preparation method, and a battery. The preparation method includes the following steps: preparing a ternary mixed salt solution as a first solution, preparing a mixed solution of titanium salt and H₂O₂ as a second solution, and preparing a suspension of carbon quantum dots as a third solution; under a protective atmosphere, simultaneously introducing the first, second, and third solutions, a precipitant solution, and a complexing agent solution into the bottom solution to carry out a co-precipitation reaction, obtaining a spherical hydroxide; calcining the spherical hydroxide, then mixing it with a lithium source and sintering it to obtain the titanium carbide-modified high-nickel ternary material. This invention incorporates carbon quantum dots and dopes Ti during the co-precipitation process, utilizing sintering to form a dispersed distribution of titanium carbide, thereby improving cycle performance by increasing particle strength. Simultaneously, titanium carbide also possesses good electrical conductivity, thus enhancing the electrochemical performance of the ternary material.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a ternary electrode material, particularly to a titanium carbide modified high-nickel ternary material, its preparation method, and a battery. Background Technology

[0002] Ultra-high energy density is the core value of solid-state batteries, and the high-capacity characteristics of high-nickel cathode materials are an indispensable partner in achieving this goal. However, existing high-nickel material systems have reached a bottleneck in specific capacity growth, and their long-term safety and cycle stability are the biggest obstacles to their perfect integration with solid-state batteries.

[0003] Existing technologies primarily improve cycle stability and safety by coating with inert materials. For example, CN113443659A discloses a quaternary cathode material co-modified by wet doping and carbon coating, and its preparation method. This method combines wet doping and surface coating as modification methods, using a co-precipitation reaction for wet doping modification, resulting in a uniform distribution of doped elements. However, the graphene in this solution does not bond well with the cathode material, and some graphene re-agglomerates during the drying process, affecting the material's performance.

[0004] CN108172804A discloses a graphene / titanium dioxide-coated cathode material, its preparation method, and its application. The preparation method involves: in a mixture of graphene oxide and titanium dioxide, stirring is performed to coat a ternary cathode material with the graphene oxide / titanium dioxide nanomaterials; then washing, filtering, and drying are performed; finally, heat treatment is conducted in an inert atmosphere to obtain a lithium-ion battery ternary cathode material coated with graphene / titanium dioxide nanomaterials. However, this method involves complex process conditions, expensive raw materials, and poor adhesion between the coating layer and the substrate.

[0005] Therefore, it is necessary to provide a modification method for high-nickel ternary materials to improve their cycle stability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a titanium carbide-modified high-nickel ternary material, its preparation method, and a battery. The preparation method involves adding carbon quantum dots and doping with Ti during the co-precipitation process, and then using sintering to form dispersed titanium carbide. This increases the cycle performance by increasing particle strength. At the same time, titanium carbide also has good electrical conductivity, thereby enhancing the electrochemical performance of the ternary material.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a titanium carbide-modified high-nickel ternary material, the method comprising the following steps:

[0009] (1) Prepare a ternary mixed salt solution as the first solution;

[0010] Prepare a mixed solution of titanium salt and H2O2 as the second solution;

[0011] A suspension of carbon quantum dots was prepared as the third solution;

[0012] (2) Under a protective atmosphere, the first solution, the second solution, the third solution, the precipitant solution and the complexing agent solution are introduced into the bottom liquid in parallel to carry out a coprecipitation reaction. After washing, drying and sieving, a spherical hydroxide is obtained.

[0013] (3) The spherical hydroxide described in step (2) is calcined, and then mixed with a lithium source and sintered to obtain titanium carbide modified high-nickel ternary material.

[0014] This invention incorporates carbon quantum dots and Ti elements during the co-precipitation process, and utilizes sintering to form dispersed titanium carbide. This increases the cycle performance by enhancing particle strength. At the same time, titanium carbide also has good electrical conductivity, thereby increasing the electrochemical performance of the ternary material.

[0015] Specifically, during cycling, the lattice of high-nickel ternary materials expands and contracts due to the repeated insertion and removal of lithium ions, leading to particle breakage or cracking. Titanium carbide, with its high hardness and excellent mechanical stability, can be uniformly distributed within the ternary material to act as a rigid framework to suppress lattice distortion and absorb stress generated by volume expansion. However, using titanium salts alone for doping can easily lead to titanium agglomeration. The synergistic use of carbon quantum dots ensures the uniform distribution of titanium salts during co-precipitation, resulting in uniform dispersion during sintering, thereby improving the cycling performance of titanium carbide-modified high-nickel ternary materials.

[0016] Preferably, the flow rates of the second solution and the third solution are such that the molar ratio of titanium salt to carbon quantum dots is 1.05:1 to 1.2:1, for example, it can be 1.05:1, 1.1:1, 1.15:1 or 1.2:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the titanium carbide doping amount in the titanium carbide modified high-nickel ternary material is 0.15wt% to 0.3wt%, for example, it can be 0.15wt%, 0.2wt%, 0.25wt% or 0.3wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the temperature of the coprecipitation reaction is 40℃ to 80℃, for example, it can be 40℃, 50℃, 60℃, 70℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the pH value of the coprecipitation reaction is 10.5 to 11.5, for example, it can be 10.5, 10.8, 11, 11.2 or 11.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the concentration of the complexing agent in the coprecipitation reaction is 0.1 mol / L to 0.5 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the coprecipitation reaction time is 60h to 100h, for example, it can be 60h, 70h, 80h, 90h or 100h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the ternary mixed salt in the ternary mixed salt solution includes nickel salt, cobalt salt and manganese salt.

[0023] Preferably, in the ternary mixed salt solution, the molar ratio of nickel, cobalt and manganese is x:y:(1-xy), where x≥0.9, 0.01≤y<0.1, and x+y=1.

[0024] Optionally, the nickel salt includes any one or a combination of at least two of nickel chloride, nickel sulfate, or nickel nitrate. Typical but non-limiting combinations include combinations of nickel chloride and nickel sulfate, nickel chloride and nickel nitrate, nickel sulfate and nickel nitrate, or combinations of nickel chloride, nickel sulfate, and nickel nitrate.

[0025] Optionally, the cobalt salt includes any one or a combination of at least two of cobalt chloride, cobalt sulfate, or cobalt nitrate. Typical but non-limiting combinations include a combination of cobalt chloride and cobalt sulfate, a combination of cobalt chloride and cobalt nitrate, a combination of cobalt sulfate and cobalt nitrate, or a combination of cobalt chloride, cobalt sulfate, and cobalt nitrate.

[0026] Optionally, the manganese salt includes any one or a combination of at least two of manganese chloride, manganese sulfate, or manganese nitrate. Typical but non-limiting combinations include manganese chloride and manganese sulfate, manganese chloride and manganese nitrate, manganese sulfate and manganese nitrate, or manganese chloride, manganese sulfate, and manganese nitrate.

[0027] Preferably, in the ternary mixed salt solution, the total molar concentration of nickel salt, cobalt salt and manganese salt is 1 mol / L to 3 mol / L, for example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the concentration of titanium salt in the second solution is 0.15 mol / L to 0.18 mol / L, for example, it can be 0.15 mol / L, 0.16 mol / L, 0.17 mol / L or 0.18 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Optionally, the titanium salt includes titanium sulfate and / or titanium oxysulfate.

[0030] Preferably, the concentration of H2O2 in the second solution is 12wt% to 15wt%, for example, it can be 12wt%, 13wt%, 14wt% or 15wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the concentration of carbon quantum dots in the third solution is 0.8wt% to 1.2wt%, for example, it can be 0.8wt%, 0.9wt%, 1wt%, 1.1wt% or 1.2wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the precipitant in the precipitant solution includes sodium hydroxide.

[0033] Preferably, the complexing agent in the complexing agent solution includes any one or a combination of at least two of ammonia, citric acid, or sodium citrate. Typical but non-limiting combinations include a combination of ammonia and citric acid, a combination of ammonia and sodium citrate, a combination of citric acid and sodium citrate, or a combination of ammonia, citric acid, and sodium citrate.

[0034] Preferably, the coprecipitation reaction is carried out under stirring conditions of 200 r / min to 400 r / min, for example, 200 r / min, 250 r / min, 300 r / min, 350 r / min or 400 r / min, but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0035] Optionally, the base solution is composed of water, a precipitant solution and a complexing agent solution, with a pH value of 11-12 and a complexing agent concentration of 0.2 mol / L-0.5 mol / L.

[0036] Preferably, the calcination method in step (3) is microwave calcination.

[0037] In conventional heat conduction calcination, heat gradually diffuses from the surface of the material to the interior, resulting in a long process and uneven heating of the material. This invention uses microwave calcination, where microwave energy is directly absorbed by the polar molecules inside the material, achieving synchronous heating of the entire material. This not only improves calcination efficiency but also ensures uniform heating of the material.

[0038] Preferably, the calcination temperature in step (3) is 950℃~1050℃, for example, it can be 950℃, 960℃, 980℃, 1000℃, 1020℃ or 1050℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the calcination time in step (3) is 3 min to 8 min, for example, it can be 3 min, 4 min, 5 min, 6 min or 8 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] Preferably, the lithium source in step (3) includes LiOH and / or Li2CO3.

[0041] To compensate for the loss during sintering, the molar ratio of the spherical hydroxide to lithium in the lithium source can be 1:1.02 to 1:1.05, for example, 1:1.02, 1:1.03, 1:1.04 or 1:1.05, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the sintering includes a first sintering and a second sintering performed sequentially; the temperature of the first sintering is 280℃~320℃, and the holding time is 2.8h~3.2h; the temperature of the second sintering is 700℃~900℃, and the holding time is 10h~16h.

[0043] In this invention, the temperature of the first sintering is 280℃~320℃, for example, it can be 280℃, 290℃, 300℃, 310℃ or 320℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] The holding time for the first sintering is 2.8h to 3.2h, for example, it can be 2.8h, 2.9h, 3h, 3.1h or 3.2h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] The second sintering temperature is 700℃~900℃, for example, it can be 700℃, 750℃, 800℃, 850℃ or 900℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] The second sintering holding time is 10h to 16h, for example, it can be 10h, 12h, 14h, 15h or 16h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] As a preferred embodiment of the preparation method described in the first aspect of the present invention, the preparation method includes the following steps:

[0048] (1) Prepare a ternary mixed salt solution as the first solution. The ternary mixed salt in the ternary mixed salt solution includes nickel salt, cobalt salt and manganese salt, and the total molar concentration of nickel salt, cobalt salt and manganese salt is 1 mol / L to 3 mol / L.

[0049] A mixed solution of titanium salt and H2O2 was prepared as a second solution, wherein the concentration of titanium salt in the second solution was 0.15 mol / L to 0.18 mol / L and the concentration of H2O2 was 12 wt% to 15 wt%.

[0050] A suspension of carbon quantum dots was prepared as the third solution, and the concentration of carbon quantum dots in the third solution was 0.8 wt% to 1.2 wt%.

[0051] Prepare a base solution with a pH of 11–12 and a complexing agent concentration of 0.2 mol / L–0.5 mol / L by mixing water, a precipitant solution, and a complexing agent solution.

[0052] (2) Under a protective atmosphere, the first solution, the second solution, the third solution, the precipitant solution and the complexing agent solution are introduced into the bottom liquid in parallel. The co-precipitation reaction is carried out at a temperature of 40℃~80℃, a pH value of 10.5~11.5, a complexing agent concentration of 0.1mol / L~0.5mol / L and a stirring speed of 200r / min~400r / min for 60h~100h. After washing, drying and sieving, spherical hydroxide is obtained.

[0053] The flow rates of the second and third solutions are such that the molar ratio of titanium salt to carbon quantum dots is 1.05:1 to 1.2:1;

[0054] (3) Microwave calcination of the spherical hydroxide described in step (2) at a temperature of 950℃~1050℃ for 3min~8min, then sintering with lithium source to obtain titanium carbide modified high nickel ternary material;

[0055] Sintering includes a first sintering and a second sintering performed sequentially; the temperature of the first sintering is 280℃~320℃, and the holding time is 2.8h~3.2h; the temperature of the second sintering is 700℃~900℃, and the holding time is 10h~16h.

[0056] The titanium carbide doping content in the titanium carbide modified high-nickel ternary material is 0.15wt% to 0.3wt%.

[0057] In a second aspect, the present invention provides a titanium carbide-modified high-nickel ternary material, wherein the titanium carbide-modified high-nickel ternary material is prepared by the preparation method described in the first aspect.

[0058] Thirdly, the present invention provides a battery comprising the titanium carbide-modified high-nickel ternary material described in the second aspect.

[0059] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] This invention incorporates carbon quantum dots and Ti doping during the co-precipitation process, forming a dispersed titanium carbide distribution through sintering. This increases particle strength and improves cycling performance. Simultaneously, titanium carbide's excellent electrical conductivity enhances the electrochemical performance of the ternary material. Specifically, during cycling, the lattice of high-nickel ternary materials expands and contracts due to repeated lithium ion insertion and removal, leading to particle breakage or cracking. Titanium carbide possesses high hardness and excellent mechanical stability. Its uniform distribution within the ternary material allows it to act as a rigid framework to suppress lattice distortion and absorb stress generated by volume expansion. However, using titanium salts alone for doping can easily lead to titanium agglomeration. The synergistic use of carbon quantum dots ensures the uniform distribution of titanium salts during co-precipitation, resulting in a uniform dispersion during sintering, thereby improving the cycling performance of the titanium carbide-modified high-nickel ternary material. Detailed Implementation

[0062] 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.

[0063] Example 1

[0064] This embodiment provides a method for preparing a titanium carbide-modified high-nickel ternary material, the method comprising the following steps:

[0065] (1) Prepare a ternary mixed salt solution as the first solution. The ternary mixed salt in the ternary mixed salt solution includes nickel sulfate, cobalt sulfate and manganese sulfate. The molar ratio of nickel, cobalt and manganese is 0.9:0.05:0.05, and the total molar concentration of nickel sulfate, cobalt sulfate and manganese sulfate is 2 mol / L.

[0066] A mixed solution of titanium sulfate and H2O2 was prepared as the second solution, with the concentration of titanium sulfate being 0.16 mol / L and the concentration of H2O2 being 14 wt%.

[0067] A suspension of carbon quantum dots was prepared as the third solution, and the concentration of carbon quantum dots in the third solution was 1 wt%.

[0068] Mix water, sodium hydroxide solution and ammonia water to prepare a base solution with a pH of 11.5 and an ammonia water concentration of 0.3 mol / L;

[0069] (2) Under nitrogen atmosphere, the first solution, the second solution, the third solution, sodium hydroxide solution and ammonia water were introduced into the bottom liquid in parallel. The co-precipitation reaction was carried out for 80 h at a temperature of 60℃, a pH value of 11, an ammonia water concentration of 0.3 mol / L and a stirring speed of 300 r / min. After washing, drying and sieving, spherical hydroxides were obtained.

[0070] The flow rates of the second and third solutions are such that the molar ratio of titanium sulfate to carbon quantum dots is 1.1:1;

[0071] (3) Microwave calcination of the spherical hydroxide described in step (2) for 5 min at a temperature of 1000℃, followed by mixing with LiOH at a molar ratio of 1:1.03 and sintering to obtain titanium carbide modified high-nickel ternary material;

[0072] Sintering includes a first sintering and a second sintering performed sequentially; the temperature of the first sintering is 300℃ and the holding time is 3 hours; the temperature of the second sintering is 800℃ and the holding time is 13 hours.

[0073] The titanium carbide doping content in the titanium carbide-modified high-nickel ternary material is 0.2 wt%.

[0074] Example 2

[0075] This embodiment provides a method for preparing a titanium carbide-modified high-nickel ternary material, the method comprising the following steps:

[0076] (1) Prepare a ternary mixed salt solution as the first solution. The ternary mixed salt in the ternary mixed salt solution includes nickel sulfate, cobalt sulfate and manganese sulfate. The molar ratio of nickel, cobalt and manganese is 0.9:0.05:0.05, and the total molar concentration of nickel sulfate, cobalt sulfate and manganese sulfate is 1 mol / L.

[0077] A mixed solution of titanium sulfate and H2O2 was prepared as the second solution, with the concentration of titanium sulfate being 0.15 mol / L and the concentration of H2O2 being 12 wt%.

[0078] A suspension of carbon quantum dots was prepared as the third solution, and the concentration of carbon quantum dots in the third solution was 0.8 wt%.

[0079] Mix water, sodium hydroxide solution and ammonia water to prepare a base solution with a pH of 11 and an ammonia water concentration of 0.2 mol / L;

[0080] (2) Under nitrogen atmosphere, the first solution, the second solution, the third solution, sodium hydroxide solution and ammonia water were introduced into the bottom liquid in parallel. The co-precipitation reaction was carried out for 100 h at a temperature of 40℃, a pH value of 10.5, an ammonia water concentration of 0.1 mol / L and a stirring speed of 200 r / min. After washing, drying and sieving, spherical hydroxides were obtained.

[0081] The flow rates of the second and third solutions are such that the molar ratio of titanium sulfate to carbon quantum dots is 1.05:1;

[0082] (3) Microwave calcination of the spherical hydroxide described in step (2) for 8 min at a temperature of 950℃, followed by mixing with LiOH at a molar ratio of 1:1.03 and sintering to obtain titanium carbide modified high-nickel ternary material;

[0083] The sintering process includes a first sintering and a second sintering, performed sequentially; the temperature of the first sintering is 280℃, and the holding time is 3.2h; the temperature of the second sintering is 700℃, and the holding time is 16h.

[0084] The titanium carbide doping amount in the titanium carbide modified high-nickel ternary material is 0.15 wt%.

[0085] Example 3

[0086] This embodiment provides a method for preparing a titanium carbide-modified high-nickel ternary material, the method comprising the following steps:

[0087] (1) Prepare a ternary mixed salt solution as the first solution. The ternary mixed salt in the ternary mixed salt solution includes nickel sulfate, cobalt sulfate and manganese sulfate. The molar ratio of nickel, cobalt and manganese is 0.9:0.05:0.05, and the total molar concentration of nickel sulfate, cobalt sulfate and manganese sulfate is 3 mol / L.

[0088] A mixed solution of titanium sulfate and H2O2 was prepared as the second solution, with the concentration of titanium sulfate being 0.18 mol / L and the concentration of H2O2 being 15 wt%.

[0089] A suspension of carbon quantum dots was prepared as the third solution, and the concentration of carbon quantum dots in the third solution was 1.2 wt%.

[0090] Mix water, sodium hydroxide solution and ammonia water to prepare a base solution with a pH of 12 and an ammonia water concentration of 0.5 mol / L;

[0091] (2) Under nitrogen atmosphere, the first solution, the second solution, the third solution, sodium hydroxide solution and ammonia water were introduced into the bottom liquid in parallel. The co-precipitation reaction was carried out for 60 h at a temperature of 80℃, a pH value of 11.5, an ammonia water concentration of 0.5 mol / L and a stirring speed of 400 r / min. After washing, drying and sieving, spherical hydroxides were obtained.

[0092] The flow rates of the second and third solutions are such that the molar ratio of titanium sulfate to carbon quantum dots is 1.2:1;

[0093] (3) Microwave calcination of the spherical hydroxide described in step (2) for 3 min at a temperature of 1050℃, followed by mixing with LiOH at a molar ratio of 1:1.03 and sintering to obtain titanium carbide modified high-nickel ternary material;

[0094] The sintering process includes a first sintering and a second sintering, performed sequentially; the temperature of the first sintering is 320℃, and the holding time is 2.8h; the temperature of the second sintering is 900℃, and the holding time is 10h.

[0095] The titanium carbide doping content in the titanium carbide-modified high-nickel ternary material is 0.3 wt%.

[0096] Example 4

[0097] This embodiment provides a method for preparing titanium carbide modified high-nickel ternary materials. Except for the flow rates of the second solution and the third solution, which make the molar ratio of titanium sulfate to carbon quantum dots 1:1, the rest is the same as in Example 1.

[0098] Example 5

[0099] This embodiment provides a method for preparing titanium carbide modified high-nickel ternary materials. Except for the flow rates of the second solution and the third solution, which make the molar ratio of titanium sulfate to carbon quantum dots 1.3:1, the rest is the same as in Example 1.

[0100] Example 6

[0101] This embodiment provides a method for preparing titanium carbide modified high-nickel ternary materials. Except that the amount of titanium carbide doping in the titanium carbide modified high-nickel ternary materials is 0.1 wt%, the rest are the same as in Example 1.

[0102] Example 7

[0103] This embodiment provides a method for preparing titanium carbide modified high-nickel ternary materials. Except that the amount of titanium carbide doping in the titanium carbide modified high-nickel ternary materials is 0.4 wt%, the rest are the same as in Example 1.

[0104] Comparative Example 1

[0105] This comparative example provides a method for preparing a high-nickel ternary material, which is the same as in Example 1 except that a second solution is not used.

[0106] Comparative Example 2

[0107] This comparative example provides a method for preparing a high-nickel ternary material, which is the same as in Example 1 except that a third solution is not used.

[0108] Comparative Example 3

[0109] This comparative example provides a method for preparing a high-nickel ternary material, which is the same as that in Example 1 except that microwave calcination was not performed.

[0110] Comparative Example 4

[0111] This comparative example provides a method for preparing a high-nickel ternary material, the method comprising the following steps:

[0112] (1) Prepare a ternary mixed salt solution as the first solution. The ternary mixed salt in the ternary mixed salt solution includes nickel sulfate, cobalt sulfate and manganese sulfate. The molar ratio of nickel, cobalt and manganese is 0.9:0.05:0.05, and the total molar concentration of nickel sulfate, cobalt sulfate and manganese sulfate is 2 mol / L.

[0113] A mixed solution of titanium sulfate, H2O2 and carbon quantum dots was prepared as a second solution. The concentration of titanium sulfate in the second solution was 0.16 mol / L, the concentration of H2O2 was 14 wt%, and the concentration of carbon quantum dots was 1 wt%.

[0114] Mix water, sodium hydroxide solution and ammonia water to prepare a base solution with a pH of 11.5 and an ammonia water concentration of 0.3 mol / L;

[0115] (2) Under nitrogen atmosphere, the first solution, the second solution, sodium hydroxide solution and ammonia water were introduced into the bottom liquid in parallel. The co-precipitation reaction was carried out for 80 h at a temperature of 60℃, a pH value of 11, an ammonia water concentration of 0.3 mol / L and a stirring speed of 300 r / min. After washing, drying and sieving, spherical hydroxides were obtained.

[0116] (3) Microwave calcination of the spherical hydroxide described in step (2) for 5 min at a temperature of 1000℃, followed by mixing with LiOH at a molar ratio of 1:1.03 and sintering to obtain titanium carbide modified high-nickel ternary material;

[0117] Sintering includes a first sintering and a second sintering performed sequentially; the temperature of the first sintering is 300℃ and the holding time is 3h; the temperature of the second sintering is 800℃ and the holding time is 13h.

[0118] Performance Characterization

[0119] The positive electrode material, polyvinylidene fluoride, and acetylene black were mixed in a mass ratio of 80:10:10, NMP (N-methylpyrrolidone) was added, and the mixture was stirred to form a slurry. This slurry was then coated onto aluminum foil, dried, and used as the positive electrode. A lithium sheet was used as the negative electrode to assemble a CR2025 coin cell. The electrochemical performance of the battery was tested at 2.8V to 4.3V, and the results are shown in Table 1.

[0120] Table 1

[0121]

[0122]

[0123] In summary, this invention incorporates carbon quantum dots and Ti doping during the co-precipitation process, forming a dispersed titanium carbide distribution through sintering. This increases particle strength and improves cycling performance. Simultaneously, titanium carbide also possesses excellent electrical conductivity, thereby enhancing the electrochemical performance of the ternary material. Specifically, during cycling, the lattice of high-nickel ternary materials expands and contracts due to repeated lithium ion insertion and removal, leading to particle breakage or cracking. Titanium carbide, with its high hardness and excellent mechanical stability, can be uniformly distributed within the ternary material, acting as a rigid framework to suppress lattice distortion and absorbing stress from volume expansion. However, using titanium salts alone for doping can easily lead to titanium agglomeration. The synergistic use of carbon quantum dots ensures the uniform distribution of titanium salts during co-precipitation, resulting in a uniform dispersion during sintering, thus improving the cycling performance of titanium carbide-modified high-nickel ternary materials.

[0124] 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 titanium carbide-modified high-nickel ternary material, characterized in that, The preparation method includes the following steps: (1) Prepare a ternary mixed salt solution as the first solution; Prepare a mixed solution of titanium salt and H2O2 as the second solution; A suspension of carbon quantum dots was prepared as the third solution; The ternary mixed salt solution comprises nickel salt, cobalt salt, and manganese salt; the molar ratio of nickel, cobalt, and manganese in the ternary mixed salt solution is x:y:(1-xy), where x≥0.9, 0.01≤y<0.1, and x+y=1; the total molar concentration of nickel salt, cobalt salt, and manganese salt in the ternary mixed salt solution is 1mol / L~3mol / L. (2) Under a protective atmosphere, the first solution, the second solution, the third solution, the precipitant solution and the complexing agent solution are introduced into the bottom liquid in parallel to carry out a co-precipitation reaction. After washing, drying and sieving, a spherical hydroxide is obtained. (3) The spherical hydroxide described in step (2) is calcined, and then mixed with a lithium source and sintered to obtain titanium carbide modified high-nickel ternary material; The calcination method is microwave calcination, the calcination temperature is 950℃~1050℃, and the calcination time is 3min~8min; The sintering includes a first sintering and a second sintering performed sequentially; the temperature of the first sintering is 280℃~320℃, and the holding time is 2.8h~3.2h; the temperature of the second sintering is 700℃~900℃, and the holding time is 10h~16h.

2. The preparation method according to claim 1, characterized in that, The temperature of the coprecipitation reaction is 40℃~80℃.

3. The preparation method according to claim 1, characterized in that, The pH value of the coprecipitation reaction is 10.5~11.

5.

4. The preparation method according to claim 1, characterized in that, The concentration of the complexing agent in the coprecipitation reaction is 0.1 mol / L to 0.5 mol / L.

5. The preparation method according to claim 1, characterized in that, The coprecipitation reaction takes 60-100 hours.

6. The preparation method according to claim 1, characterized in that, The concentration of titanium salt in the second solution is 0.15 mol / L to 0.18 mol / L.

7. The preparation method according to claim 1, characterized in that, The concentration of H2O2 in the second solution is 12wt%~15wt%.

8. The preparation method according to claim 1, characterized in that, The concentration of carbon quantum dots in the third solution is 0.8 wt% to 1.2 wt%. The flow rates of the second and third solutions are such that the molar ratio of titanium salt to carbon quantum dots is 1.05:1 to 1.2:

1.

9. The preparation method according to claim 1, characterized in that, The precipitant in the precipitant solution includes sodium hydroxide.

10. The preparation method according to claim 1, characterized in that, The complexing agent in the complexing agent solution includes any one or a combination of at least two of ammonia, citric acid, or sodium citrate.

11. The preparation method according to claim 1, characterized in that, The coprecipitation reaction was carried out under stirring conditions of 200 r / min to 400 r / min.

12. The preparation method according to claim 1, characterized in that, The lithium source in step (3) includes LiOH and / or Li2CO3.

13. The preparation method according to claim 1, characterized in that, The titanium carbide doping content in the titanium carbide modified high-nickel ternary material is 0.15wt%~0.3wt%.

14. A titanium carbide-modified high-nickel ternary material, characterized in that, The titanium carbide modified high-nickel ternary material is prepared by the preparation method described in any one of claims 1 to 13.

15. A battery, characterized in that, The battery comprises the titanium carbide modified high-nickel ternary material as described in claim 14.

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