Modified cobalt tetraoxide, and preparation method and application thereof

Abstract

The application discloses modified tricobalt tetraoxide and a preparation method and application thereof, and belongs to the technical field of battery materials. The modified tricobalt tetraoxide is doped with rare earth elements and aluminum simultaneously; the total doping amount of the rare earth elements is not more than 0.5% in terms of mass percentage; and the doping amount of the aluminum is not more than 1.2%. The modified tricobalt tetraoxide has a relatively compact structure and high mechanical strength, is not easy to be broken during calcination, and has no surface floating powder phenomenon, so that the electrochemical performance of downstream product lithium cobaltate positive electrode material is improved.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a modified cobalt tetroxide, its preparation method, and its application. Background Technology

[0002] Lithium cobalt oxide is widely used in the market due to its high operating voltage, high theoretical specific capacity, and high energy density. However, structural degradation means that only half of the lithium ions can be released, resulting in an actual capacity of only about 50% of the theoretical capacity. For many years, numerous studies have been conducted on how to improve the specific capacity and cycle performance of lithium-ion batteries, with doping being one of the most researched methods.

[0003] Cobalt tetroxide is a key precursor for the preparation of lithium cobalt oxide. Currently, it is mainly produced by wet synthesis-high temperature calcination process. However, cobalt tetroxide particles doped with rare earth elements by the above method often have a loose structure, low mechanical strength, are easily broken, have serious surface powder floating phenomenon, and poor particle size distribution uniformity, making it difficult to obtain lithium cobalt oxide cathode materials with good electrochemical performance.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a modified cobalt tetroxide, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a modified cobalt tetroxide, wherein the modified cobalt tetroxide is simultaneously doped with rare earth elements and aluminum; the total doping amount of rare earth elements does not exceed 0.5% by mass percentage, and the doping amount of aluminum does not exceed 1.2%.

[0007] Optionally, the modified cobalt tetroxide has at least one of the following characteristics: Feature 1: D of modified cobalt tetroxide 50 The thickness is 3μm to 5μm; Feature 2: Aluminum and rare earth elements are evenly distributed in modified cobalt tetroxide; Feature 3: By mass percentage, modified cobalt tetroxide contains 71%~72% Co, 0.75%~1.20% Al, and 0.1%~0.5% rare earth elements; Feature 4: The tap density of the modified cobalt tetroxide is 2.0 g / cm³. 3 ~2.3g / cm 3 ; Feature 5: The modified cobalt tetroxide D 00 Its thickness ranges from 1.25 μm to 2.5 μm. Feature 6: The modified cobalt tetroxide D 10 Its thickness ranges from 2.1 μm to 3.8 μm. Feature 7: The modified cobalt tetroxide D 90 Its thickness ranges from 5.4 μm to 6.35 μm. Feature 8: The modified cobalt tetroxide D 100 Its thickness ranges from 7.5 μm to 11.5 μm. Feature 9: The QD of the modified cobalt tetroxide is 0.4~0.97, where QD=(D 90 -D 10 ) / D 50 .

[0008] Optionally, the modified cobalt tetroxide also contains a metallic element X, which includes at least one of Zr, Mg, Ni and Mn.

[0009] Secondly, the present invention provides a method for preparing modified cobalt tetroxide as described in the foregoing embodiments, comprising the following steps: A mixed metal salt solution and a carbonate solution are fed into a synthesis reactor with carbonate and water as the base liquid in a parallel flow to carry out a synthesis reaction and obtain cobalt carbonate seed crystals; wherein the mixed metal salt solution includes at least soluble rare earth metal salts, cobalt salts and aluminum salts. A mixed metal salt solution and a carbonate solution are added to the synthesis reactor to allow cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate particles grown in one step. The primary cobalt carbonate particles are transferred into a growth reactor. A mixed metal salt solution and a carbonate solution are then added to the growth reactor in a co-current feeding manner to mix and react, so that the primary cobalt carbonate particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size. The secondary growth process includes multiple gradient heating. Cobalt carbonate particles that have reached the preset particle size are calcined to obtain cobalt tetroxide.

[0010] In an optional embodiment, the concentration of cobalt ions in the mixed metal salt solution is 80 g / L to 145 g / L, the concentration of aluminum ions is 1.0 g / L to 2.0 g / L, and the concentration of each rare earth element is 0.05 g / L to 0.5 g / L.

[0011] Optionally, the mixed metal salt solution also contains element X at a concentration of 0.05 g / L to 0.5 g / L.

[0012] Optionally, the cobalt salt includes at least one of cobalt sulfate, cobalt chloride, and cobalt nitrate.

[0013] Optionally, the aluminum salt includes at least one of aluminum sulfate, aluminum chloride, and aluminum nitrate.

[0014] Optionally, the soluble rare earth metal salt includes at least one of yttrium, lanthanum, cerium, ytterbium, terbium, erbium, scandium, praseodymium, and neodymium.

[0015] Optionally, the carbonate solution includes at least one of ammonium bicarbonate solution, ammonium carbonate solution, sodium bicarbonate solution, and sodium carbonate solution.

[0016] Optionally, the carbonate concentration in the carbonate solution is 180 g / L to 240 g / L.

[0017] Optionally, the concentration of carbonate in the base solution is 30 g / L to 60 g / L.

[0018] In an optional embodiment, the synthesis reaction includes at least one of the following features: Feature 10: The reaction temperature for obtaining cobalt carbonate seeds is 20℃~40℃; Feature 11: The reaction pH for obtaining cobalt carbonate seeds is 8.0~9.0; Feature 12: During the reaction process to obtain cobalt carbonate seeds, the flow rate of the mixed metal salt solution is 2%V / h~4%V / h, where V is the volume of the reaction vessel; Feature 13: The cobalt carbonate seed crystals have a particle size of 1.5μm~2.5μm.

[0019] In an optional implementation, a single growth includes at least one of the following features: Feature 14: The temperature for primary growth is 30℃~50℃; Feature 15: The pH value for primary growth is 7.0~8.0; Feature 16: During a single growth process, the flow rate of the mixed metal salt solution is 3%V / h to 5%V / h; Feature 17: At the end of the first growth, the particle size of the cobalt carbonate particles is 3.0 μm to 5.0 μm.

[0020] In an optional implementation, secondary growth includes at least one of the following features: Feature 18: The temperature of the entire secondary growth process is 30℃~60℃; optionally, during the gradient heating process, the temperature is increased by 1℃~4℃ each time; Feature 19: The pH value for secondary growth is 6.5~8.0; Feature 20: During the secondary growth process, the flow rate of the mixed metal salt solution is 1%V / h~5%V / h; Feature 21: The preset particle size of cobalt carbonate particles is 4.0μm~6.0μm.

[0021] In an optional implementation, the cobalt carbonate particles that have reached the preset particle size are first washed and dried, and then calcined. Alternatively, water may be used for washing; Optionally, the washing temperature is 50℃~80℃; Optionally, the washing time is 20 to 50 minutes; Optionally, the calcination temperature is 300℃~900℃.

[0022] Thirdly, the present invention provides a lithium cobalt oxide cathode material, which is prepared using the modified cobalt tetroxide of the aforementioned embodiments as a precursor.

[0023] Fourthly, the present invention provides a lithium-ion battery comprising the lithium cobalt oxide cathode material of the aforementioned embodiments.

[0024] The beneficial effects of this invention include: This invention simultaneously dops cobalt tetroxide (Co3O4) with Al and rare earth elements. On one hand, Al doping improves the structural stability of the lithium cobalt oxide cathode material, thereby enhancing its cycle performance under high voltage. On the other hand, rare earth doping increases the cell volume of the lithium cobalt oxide cathode material and improves lithium-ion diffusion conditions, thus increasing its discharge capacity. By co-doping with Al and rare earth elements, the electrochemical performance of lithium cobalt oxide cathode materials further prepared from Co3O4 can be effectively improved.

[0025] Furthermore, this invention creatively employs a gradient heating combined with wet controlled crystallization technology. By selectively weakening the crystalline order of the inner layer of the material, it precisely controls the crystalline intensity gradient between the inner and outer layers of the particles during precipitation, optimizes the eutectic environment, and promotes the synchronous deposition and lattice embedding of heterogeneous elements such as rare earth and aluminum. Ultimately, this achieves a uniform distribution of these elements in the cobalt tetroxide bulk phase, improves the bonding strength between primary particles of doped cobalt tetroxide, and significantly alleviates the problems of floating powder and broken particles that occur in rare earth doped samples. The resulting modified cobalt tetroxide exhibits a uniform distribution of doping elements, uniform particle size, relatively dense structure, and high mechanical strength. It is not easily broken during calcination and exhibits virtually no surface powder floating phenomenon, which is beneficial for improving the electrochemical performance of downstream products such as lithium cobalt oxide cathode materials. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 Here is a SEM image of the cobalt carbonate prepared in Example 1; Figure 2Here is a SEM image of the modified cobalt tetroxide prepared in Example 1; Figure 3 The particle size distribution diagram is shown for the modified cobalt tetroxide prepared in Example 1. Figure 4 Here is a SEM image of the cobalt carbonate prepared in Example 2; Figure 5 Here is a SEM image of the modified cobalt tetroxide prepared in Example 2; Figure 6 The particle size distribution diagram is shown for the modified cobalt tetroxide prepared in Example 2. Figure 7 SEM image of cobalt carbonate prepared in Comparative Example 1; Figure 8 The image shows a SEM image of the modified cobalt tetroxide prepared in Comparative Example 1. Figure 9 The particle size distribution diagram of the modified cobalt tetroxide prepared in Comparative Example 1 is shown. Figure 10 SEM image of cobalt carbonate prepared in Comparative Example 2; Figure 11 SEM image of the modified cobalt tetroxide prepared in Comparative Example 2; Figure 12 The particle size distribution diagram is shown for the modified cobalt tetroxide prepared in Comparative Example 2. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0029] The modified cobalt tetroxide, its preparation method, and its applications provided by this invention will be described in detail below.

[0030] This invention provides a modified cobalt tetroxide, which is simultaneously doped with rare earth elements and aluminum. By doping, the crystal structure, electronic structure, or chemical properties of the material are altered, thereby improving the material's performance.

[0031] Al enhances the lattice interaction between transition metals and oxygen, thereby improving the structural stability of lithium cobalt oxide cathode materials and thus improving their cycle performance under high voltage. However, Al is electrochemically inert, and excessive doping can negatively impact capacitance. Therefore, this invention employs a method of co-doping Al and rare earth elements in the lithium cobalt oxide cathode material precursor. Rare earth elements possess a unique 4f electron layer structure and a large ionic radius; doping with these elements increases the cell volume of the lithium cobalt oxide cathode material and improves lithium-ion diffusion conditions, thereby enhancing its discharge capacity. By co-doping Al and rare earth elements, the electrochemical performance of lithium cobalt oxide cathode materials further prepared from cobalt tetroxide can be effectively improved.

[0032] In some alternative implementations, the aluminum doping amount does not exceed 1.2% by mass percentage, such as 1.2%, 1.1%, 1.0%, 0.8%, 0.5%, 0.2%, 0.1%, 0.05%, or 0.01%, or other values ​​greater than 0 and not exceeding 1.2%.

[0033] If the aluminum doping amount exceeds 1.2%, it will make the morphology difficult to control and will easily affect the capacitance of the cathode material.

[0034] In some optional embodiments, the total doping amount of rare earth elements, by mass percentage, does not exceed 0.5%, such as 0.5%, 0.45%, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, 0.05%, or 0.01%, or other values ​​greater than 0 but not exceeding 0.5%. The rare earth elements mentioned above may, by example but not exclusively, include at least one of yttrium, lanthanum, cerium, ytterbium, terbium, erbium, scandium, praseodymium, and neodymium. As a further optionality, the rare earth element may be only lanthanum, or may include both lanthanum and yttrium.

[0035] If the total doping amount of rare earth elements exceeds 0.5%, it can easily lead to a decrease in the tap density (TD) of cobalt tetroxide, which is not conducive to the processing of downstream cathode materials.

[0036] In some preferred embodiments, the modified cobalt tetroxide may contain 71% to 72% Co, 0.75% to 1.20% Al, and 0.1% to 0.5% rare earth elements by mass percentage.

[0037] Furthermore, the modified cobalt tetroxide may also contain a metallic element X, including at least one of Zr, Mg, Ni and Mn.

[0038] In some alternative embodiments, the modified cobalt tetroxide contains Co, Al, Y, and La; in other alternative embodiments, the modified cobalt tetroxide contains Co, Al, Cr, and La.

[0039] In some alternative embodiments, the modified cobalt tetroxide D 50 The size is 3μm to 5μm.

[0040] In some alternative embodiments, the modified cobalt tetroxide D 00 The size ranges from 1.25 μm to 2.5 μm.

[0041] In some alternative embodiments, the modified cobalt tetroxide D 10 The size ranges from 2.1 μm to 3.8 μm.

[0042] In some alternative embodiments, the modified cobalt tetroxide D 90 The thickness ranges from 5.4 μm to 6.35 μm.

[0043] In some alternative embodiments, the modified cobalt tetroxide D 100 The size ranges from 7.5μm to 11.5μm.

[0044] In some optional embodiments, the QD of the modified cobalt tetroxide is 0.4~0.97, where QD=(D 90 -D 10 ) / D 50 .

[0045] In some alternative embodiments, the tap density of the modified cobalt tetroxide is 2.0 g / cm³. 3 ~2.3g / cm 3 .

[0046] In some alternative embodiments, aluminum and rare earth elements are uniformly distributed in the modified cobalt tetroxide. In particular, no aluminum enrichment is observed on the surface of the modified cobalt tetroxide.

[0047] As mentioned above, the cobalt tetroxide provided by this invention has a uniform distribution of doping elements, uniform particle size, relatively dense structure (high tap density), high mechanical strength, is not easily broken during calcination, and has virtually no surface powder floating phenomenon, which is beneficial to improving the electrochemical performance of downstream products such as lithium cobalt oxide cathode materials.

[0048] Accordingly, the present invention also provides a method for preparing the above-mentioned modified cobalt tetroxide, which mainly uses a mixed metal salt solution co-doped with rare earth and Al as raw materials and ammonium bicarbonate as precipitant, and adopts a wet co-precipitation-high temperature calcination method to obtain modified cobalt tetroxide.

[0049] The preparation process includes the following steps: S1 (seed preparation process): The mixed metal salt solution and carbonate solution are fed into the synthesis reactor with carbonate and water as the base liquid in a parallel flow to carry out the synthesis reaction and obtain cobalt carbonate seed crystals.

[0050] In some optional embodiments, under stirring conditions, the mixed metal salt solution and carbonate solution are added in a parallel flow to a synthesis reactor using carbonate and water as the base liquid for the synthesis reaction. The stirring speed can be 200 rpm to 400 rpm.

[0051] In some optional embodiments, the mixed metal salt solution includes at least a soluble rare earth metal salt, a cobalt salt, and an aluminum salt. The mixed metal salt solution can be obtained by dissolving the soluble rare earth metal salt, cobalt salt, and aluminum salt in water. Alternatively, the mixed metal salt solution can be obtained by dissolving the soluble rare earth metal salt, cobalt salt, X salt, and aluminum salt in water, wherein X includes at least one of Zr, Mg, Ni, and Mn.

[0052] In some optional embodiments, the cobalt ion concentration in the mixed metal salt solution is 80 g / L to 145 g / L, the aluminum ion concentration is 1.0 g / L to 2.0 g / L, and the rare earth element concentration is 0.05 g / L to 0.5 g / L. When the mixed metal salt solution contains salt X, the concentration of salt X ions in the mixed metal salt solution can be 0.05 g / L to 0.5 g / L.

[0053] The cobalt ion concentration can be 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L or 145 g / L, or other values ​​within the range of 80 g / L to 145 g / L.

[0054] The aluminum ion concentration can be 1 g / L, 1.2 g / L, 1.5 g / L, 1.8 g / L or 2 g / L, or other values ​​in the range of 1.0 g / L to 2.0 g / L.

[0055] The concentration of each rare earth element can be 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L or 0.5 g / L, or other values ​​within the range of 0.05 g / L to 0.5 g / L.

[0056] The concentration of X ions can be 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, or 0.5 g / L, or other values ​​within the range of 0.05 g / L to 0.5 g / L.

[0057] In some alternative embodiments, the cobalt salt may, by way of example but not limitation, include at least one of cobalt sulfate, cobalt chloride and cobalt nitrate.

[0058] Aluminum salts may include, by way of example but not by way of limitation, at least one of aluminum sulfate, aluminum chloride and aluminum nitrate.

[0059] Salt X may, by way of example but not limitation, include at least one of the sulfate, chloride and nitrate salts of element X.

[0060] Soluble rare earth metal salts may, by way of example but not by way of limitation, include at least one of yttrium salts, lanthanum salts, cerium salts, ytterbium salts, terbium salts, erbium salts, scandium salts, praseodymium salts, and neodymium salts.

[0061] In some alternative embodiments, the carbonate solution may, by way of example but not limitation, include at least one of ammonium bicarbonate solution, ammonium carbonate solution, sodium bicarbonate solution and sodium carbonate solution.

[0062] In the above carbonate solution, the concentration of carbonate can be 180 g / L to 240 g / L, such as 180 g / L, 190 g / L, 200 g / L, 210 g / L, 220 g / L, 230 g / L or 240 g / L, or other values ​​within the range of 180 g / L to 240 g / L.

[0063] In some alternative embodiments, the concentration of carbonate in the substrate can be from 30 g / L to 60 g / L, such as 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, or 60 g / L, or other values ​​within the range of 30 g / L to 60 g / L. Similarly, the carbonate in the substrate may, by way of example but not limitation, include at least one of ammonium bicarbonate, ammonium carbonate, sodium bicarbonate, and sodium carbonate.

[0064] In some alternative embodiments, the reaction temperature for obtaining cobalt carbonate seed crystals can be 20°C to 40°C, such as 20°C, 25°C, 30°C, 35°C or 40°C, or other values ​​within the range of 20°C to 40°C.

[0065] In some alternative embodiments, the reaction pH value for obtaining cobalt carbonate seed crystals can be 8.0 to 9.0, such as 8.0, 8.2, 8.5, 8.8 or 9.0, or other values ​​in the range of 8.0 to 9.0.

[0066] In some optional embodiments, during the reaction process to obtain cobalt carbonate seeds, the flow rate of the mixed metal salt solution can be 2%V / h to 4%V / h, such as 2%V / h, 2.5%V / h, 3%V / h, 3.5%V / h, or 4%V / h, or other values ​​within the range of 2%V / h to 4%V / h. Wherein, V is the volume of the reaction vessel, the same applies below.

[0067] In some alternative embodiments, the particle size of the cobalt carbonate seed crystals can be 1.5 μm to 2.5 μm, such as 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm or 2.5 μm, or other values ​​within the range of 1.5 μm to 2.5 μm.

[0068] S2 (first growth process): Continue to add mixed metal salt solution and carbonate solution to the synthesis reactor to allow cobalt carbonate seed crystals to grow in the first stage, and obtain cobalt carbonate first-growth particles.

[0069] In some alternative implementations, a single growth process is carried out using a multi-round cyclic feeding method.

[0070] In some alternative implementations, the temperature for a single growth cycle can be 30°C to 50°C, such as 30°C, 35°C, 40°C, 45°C, or 50°C, or other values ​​within the range of 30°C to 50°C.

[0071] In some alternative implementations, the pH value for the primary growth can be 7.0 to 8.0, such as 7.0, 7.2, 7.5, 7.8 or 8.0, or other values ​​in the range of 7.0 to 8.0.

[0072] In some alternative implementations, the flow rate of the mixed metal salt solution during a single growth process can be 3%V / h to 5%V / h, such as 3%V / h, 3.5%V / h, 4%V / h, 4.5%V / h, or 5%V / h, or other values ​​within the range of 3%V / h to 5%V / h.

[0073] In some alternative embodiments, at the end of a single growth cycle, the particle size of the cobalt carbonate primary growth particles is 3.0 μm to 5.0 μm, such as 3.0 μm, 3.2 μm, 3.5 μm, 4.0 μm, 4.5 μm or 5.0 μm, or other values ​​within the range of 3.0 μm to 5.0 μm.

[0074] S3 (Secondary Growth Process): The cobalt carbonate primary growth particles are transferred into the growth reactor. The mixed metal salt solution and carbonate solution are added to the growth reactor in a co-current feeding manner to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size. The secondary growth process includes multiple gradient heating.

[0075] By repeatedly increasing the temperature in gradients, the crystallization strength of the inner and outer layers of cobalt carbonate can be optimized, and the interaction force between particles can be enhanced. This ensures that the inner and outer layers shrink uniformly during subsequent calcination, resulting in better sphericity of the sample and avoiding issues such as powdering and breakage on the surface.

[0076] In some alternative implementations, the pH value for secondary growth can be 6.5 to 8.0, such as 6.5, 6.8, 7.0, 7.2, 7.5, 7.8 or 8.0, or other values ​​within the range of 6.5 to 8.0.

[0077] In some alternative implementations, the temperature of the entire secondary growth process can be 30℃~60℃, such as 30℃, 35℃, 40℃, 45℃, 50℃, 55℃ or 60℃, or other values ​​within the range of 30℃~60℃.

[0078] In some preferred embodiments, during the gradient heating process, the temperature is increased by 1°C to 4°C each time, such as 1°C, 1.5°C, 2°C, 2.5°C, 3°C, 3.5°C, or 4°C, or other values ​​within the range of 1°C to 4°C. More specifically, the temperature increases by 1°C to 4°C with each feeding cycle. If the temperature increase is less than 1°C each time, it is not conducive to improving and optimizing crystallinity.

[0079] In some alternative embodiments, during the secondary growth process, the flow rate of the mixed metal salt solution can be 1%V / h to 5%V / h, such as 1%V / h, 2%V / h, 3%V / h, 4%V / h or 5%V / h, or other values ​​within the range of 1%V / h to 5%V / h.

[0080] It should be noted that rare earth ions and cobalt ions differ significantly in radius and valence state, resulting in low lattice matching. This inhibits the growth and fusion of cobalt tetroxide grains, making them prone to breakage and surface enrichment of dopant elements during calcination, hindering the formation of a uniformly distributed bulk doped structure and affecting the consistency and stability of material properties. This invention creatively employs a gradient heating combined with wet controlled crystallization technology. By selectively weakening the crystalline order of the inner layer of the material, it precisely controls the crystalline intensity gradient between the inner and outer layers of the particles during precipitation, optimizing the eutectic environment and promoting the synchronous deposition and lattice embedding of rare earth elements and heterogeneous elements such as aluminum. Ultimately, this achieves a uniform distribution of rare earth elements in the bulk cobalt tetroxide, improves the bonding strength between primary particles of doped cobalt tetroxide, and significantly improves the problems of floating powder and broken particles observed in rare earth doped samples.

[0081] In some optional embodiments, the preset particle size of cobalt carbonate particles can be 4.0 μm to 6.0 μm, such as 4 μm, 4.5 μm, 5 μm, 5.5 μm or 6 μm, or other values ​​within the range of 4.0 μm to 6.0 μm.

[0082] S4: Calcining cobalt carbonate particles that have reached the preset particle size yields cobalt tetroxide.

[0083] In some alternative implementations, the cobalt carbonate particles that have reached a preset particle size are first washed and dried, and then calcined.

[0084] In some alternative implementations, water is used for washing.

[0085] The washing temperature can be 50℃~80℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, or other values ​​within the range of 50℃~80℃.

[0086] The washing time can be 20min to 50min, such as 20min, 25min, 30min, 35min, 40min, 45min or 50min, or other values ​​within the range of 20min to 50min.

[0087] In some alternative implementations, drying may be performed using flash drying.

[0088] In some alternative embodiments, the calcination temperature can be 300℃~900℃, such as 300℃, 400℃, 500℃, 600℃, 700℃, 800℃ or 900℃, or other values ​​within the range of 300℃~900℃.

[0089] The calcination time can be 1h to 5h, such as 1h, 2h, 3h, 4h or 5h, or other values ​​within the range of 1h to 5h.

[0090] Continuing from the above, the above preparation method can produce doped small-diameter spherical cobalt tetroxide with uniform particle size and uniform element distribution.

[0091] In addition, the present invention also provides a lithium cobalt oxide cathode material, which is prepared using the above-mentioned modified cobalt tetroxide as a precursor.

[0092] In addition, the present invention also provides a lithium-ion battery comprising the above-mentioned lithium cobalt oxide cathode material.

[0093] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0094] Example 1 This embodiment provides a modified cobalt tetroxide, the preparation method of which includes: S1: Seed preparation.

[0095] Ammonium bicarbonate and pure water were added to the synthesis reactor as a base solution, with an ammonium bicarbonate concentration of 40 g / L. Stirring was started (stirring speed 300 rpm), and the temperature was raised to 35°C. A mixed metal sulfate solution and an ammonium bicarbonate solution were added to the reactor in a co-current flow to carry out the synthesis reaction. The flow rate of the mixed metal salt solution was 3% V / h. The pH value of the reaction was controlled within the range of 8.0–9.0, and a particle size D was obtained. 50 It is a 1.7 μm cobalt carbonate seed crystal.

[0096] The preparation of the mixed metal sulfate solution includes mixing cobalt sulfate, aluminum sulfate, yttrium sulfate, and lanthanum sulfate in a certain proportion to prepare a mixed metal sulfate solution with a cobalt ion concentration of 130 g / L, an aluminum to cobalt mass ratio of 0.014 (aluminum ion concentration of 1.82 g / L), a yttrium to cobalt mass ratio of 0.0028 (yttrium ion concentration of 0.36 g / L), and a lanthanum to cobalt mass ratio of 0.0028 (lanthanum ion concentration of 0.36 g / L).

[0097] The preparation of ammonium bicarbonate solution includes: mixing ammonium bicarbonate with pure water to prepare an ammonium bicarbonate solution with a concentration of 220 g / L.

[0098] S2: Primary growth.

[0099] A mixed metal sulfate solution and an ammonium bicarbonate solution are added to the synthesis reactor to allow cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate primary growth particles.

[0100] The mixed metal salt solution flow rate was 4%V / h, the primary growth temperature was 40℃, and the pH value was 7.0~8.0. Multiple cycles of feeding were used to grow the cobalt carbonate particles to D0.0 in the primary growth stage. 50 It is 3.4μm.

[0101] S3: Secondary growth.

[0102] The cobalt carbonate primary growth particles are transferred into a growth reactor. The mixed metal salt solution and carbonate solution are added to the growth reactor in a parallel flow to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size.

[0103] The secondary growth process involves a pH range of 6.5–8.0, employing a gradient heating method. The initial temperature is 34°C, with the temperature increasing by 2°C with each subsequent feeding cycle. The flow rate of the mixed metal salt solution is 3%V / h. The ammonium bicarbonate solution feed pump flow rate is adjusted according to a mass ratio of 0.30 between the mixed metal sulfate solution and the ammonium bicarbonate solution, and the cobalt carbonate particles are fed in parallel to grow to the D-size. 50 It is 5.0 μm.

[0104] S4: Washing, drying, and calcining.

[0105] The cobalt carbonate granule slurry in S3 was fed into a centrifuge and washed with 70°C water for 30 min. After centrifugation and dehydration, it was dried using a flash evaporator to obtain dry, small-particle-size cobalt carbonate doped with rare earth elements. The washed and dried cobalt carbonate was calcined at 850°C for 1 h and sieved (vibrating screen frequency of 3.8 kHz) to obtain small-particle-size cobalt tetroxide doped with rare earth elements and Al.

[0106] Example 2 This embodiment provides a modified cobalt tetroxide, the preparation method of which includes: S1: Seed preparation.

[0107] Ammonium bicarbonate and pure water were added to the synthesis reactor as a base solution, with an ammonium bicarbonate concentration of 40 g / L. Stirring was started (stirring speed 340 rpm), and the temperature was raised to 32°C. A mixed metal sulfate solution and an ammonium bicarbonate solution were added to the reactor in a co-current flow to carry out the synthesis reaction. The flow rate of the mixed metal salt solution was 3.5% V / h. The pH value of the reaction was controlled within the range of 8.0–9.0, and a particle size D was obtained. 50 It is a 1.7 μm cobalt carbonate seed crystal.

[0108] The preparation of the mixed metal sulfate solution includes mixing cobalt sulfate, aluminum sulfate, zirconium sulfate, and lanthanum sulfate in a certain proportion to prepare a mixed metal sulfate solution with a cobalt ion concentration of 140 g / L, an aluminum to cobalt mass ratio of 0.011 (aluminum ion concentration of 1.54 g / L), a zirconium to cobalt mass ratio of 0.0011 (zirconium ion concentration of 0.15 g / L), and a lanthanum to cobalt mass ratio of 0.0007 (lanthanum ion concentration of 0.098 g / L).

[0109] The preparation of ammonium bicarbonate solution includes: mixing ammonium bicarbonate with pure water to prepare an ammonium bicarbonate solution with a concentration of 230 g / L.

[0110] S2: Primary growth.

[0111] A mixed metal sulfate solution and an ammonium bicarbonate solution are added to the synthesis reactor to allow cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate primary growth particles.

[0112] The mixed metal salt solution flow rate was 4.2%V / h, the primary growth temperature was 37℃, and the pH value was 7.0~8.0. Multiple cycles of feeding were used to grow the cobalt carbonate particles to D0.0 in the primary growth stage. 50 It is 3.2μm.

[0113] S3: Secondary growth.

[0114] The cobalt carbonate primary growth particles are transferred into a growth reactor. The mixed metal salt solution and carbonate solution are added to the growth reactor in a parallel flow to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size.

[0115] The secondary growth process maintained a pH of 6.5–8.0, employing a gradient heating method. The initial temperature was 33°C, with the temperature increasing by 3°C with each cycle. The mixed metal salt solution flow rate was 3.5%V / h. The ammonium bicarbonate solution feed pump flow rate was adjusted according to a mass ratio of 0.35 (mixed metal sulfate solution to ammonium bicarbonate solution), and the cobalt carbonate particles were fed in parallel to grow to the D-size. 50 It is 4.5μm.

[0116] S4: Washing, drying, and calcining.

[0117] The cobalt carbonate granule slurry in S3 was fed into a centrifuge and washed with 70°C water for 25 minutes. After centrifugation and dehydration, it was dried using a flash evaporator to obtain dry, small-particle-size cobalt carbonate doped with rare earth elements. The washed and dried cobalt carbonate was calcined at 810°C for 2 hours and then sieved (vibrating screen frequency of 3.8kHz) to obtain small-particle-size cobalt tetroxide doped with rare earth elements and Al.

[0118] Example 3 This embodiment provides a modified cobalt tetroxide, the preparation method of which includes: S1: Seed preparation.

[0119] Ammonium carbonate and pure water were added to the synthesis reactor as a base solution, with an ammonium carbonate concentration of 30 g / L. Stirring was started (stirring speed 400 rpm), and the temperature was raised to 20°C. A mixed metal hydrochloride solution and an ammonium carbonate solution were added to the reactor in a co-current flow to carry out the synthesis reaction. The flow rate of the mixed metal salt solution was 2% V / h. The pH value of the reaction was controlled within the range of 8.0–9.0, and a particle size D was obtained. 50 It is a 1.5μm cobalt carbonate seed crystal.

[0120] The preparation of the mixed metal hydrochloride solution includes mixing cobalt chloride, aluminum chloride, yttrium chloride, and lanthanum chloride in a certain proportion to prepare a mixed metal hydrochloride solution with a cobalt ion concentration of 80 g / L, an aluminum ion concentration of 1.0 g / L, a yttrium ion concentration of 0.05 g / L, and a lanthanum ion concentration of 0.05 g / L.

[0121] The preparation of the ammonium carbonate solution includes mixing ammonium carbonate with pure water to prepare an ammonium carbonate solution with a concentration of 180 g / L.

[0122] S2: Primary growth.

[0123] A mixed metal hydrochloride solution and an ammonium carbonate solution are added to the synthesis reactor to allow cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate primary growth particles.

[0124] The mixed metal salt solution flow rate was 3%V / h, the primary growth temperature was 30℃, and the pH value was 7.0~8.0. Multiple cycles of feeding were used to grow the cobalt carbonate particles to D size in the primary growth process. 50 It is 3.0 μm.

[0125] S3: Secondary growth.

[0126] The cobalt carbonate primary growth particles are transferred into a growth reactor. The mixed metal hydrochloride solution and ammonium carbonate solution are added to the growth reactor in a parallel flow to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size.

[0127] The secondary growth process involves a pH range of 6.5–8.0, employing a gradient heating method. The initial temperature is 40°C, with the temperature increasing by 1°C with each subsequent feeding cycle. The flow rate of the mixed metal salt solution is 5%V / h. Based on a mass ratio of 0.32 between the mixed metal hydrochloride solution and the ammonium carbonate solution, the flow rate of the ammonium carbonate feed pump is adjusted, and the cobalt carbonate particles are fed in parallel to grow to the D-size. 50 It is 4.0 μm.

[0128] S4: Washing, drying, and calcining.

[0129] The cobalt carbonate granule slurry in S3 was fed into a centrifuge and washed with 50°C water for 50 min. After centrifugation and dehydration, it was dried using a flash evaporator to obtain dry, small-particle-size cobalt carbonate doped with rare earth elements. The washed and dried cobalt carbonate was calcined at 300°C for 5 h and then sieved (vibrating screen frequency of 3.8 kHz) to obtain small-particle-size cobalt tetroxide doped with rare earth elements and Al.

[0130] Example 4 This embodiment provides a modified cobalt tetroxide, the preparation method of which includes: S1: Seed preparation.

[0131] Sodium bicarbonate and pure water were added to the synthesis reactor as a base solution, with a sodium bicarbonate concentration of 60 g / L. Stirring was started (stirring speed 200 rpm), and the temperature was raised to 40°C. A mixed metal nitrate solution and a sodium bicarbonate solution were added to the reactor in a co-current flow to carry out the synthesis reaction. The flow rate of the mixed metal salt solution was 4% V / h. The pH value of the reaction was controlled within the range of 8.0–9.0, and a particle size D was obtained. 50 It is a 2.5μm cobalt carbonate seed crystal.

[0132] The preparation of the mixed metal nitrate solution includes mixing cobalt nitrate, aluminum nitrate, yttrium nitrate, and lanthanum nitrate in a certain proportion to prepare a mixed metal nitrate solution with a cobalt ion concentration of 145 g / L, an aluminum ion concentration of 2.0 g / L, a yttrium ion concentration of 0.5 g / L, and a lanthanum ion concentration of 0.5 g / L.

[0133] The preparation of sodium bicarbonate solution includes: mixing sodium bicarbonate with pure water to prepare a sodium bicarbonate solution with a concentration of 240 g / L.

[0134] S2: Primary growth.

[0135] A mixed metal nitrate solution and a sodium bicarbonate solution are added to the synthesis reactor to allow cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate particles grown in one step.

[0136] The mixed metal salt solution flow rate was 5%V / h, the primary growth temperature was 50℃, and the pH value was 7.0~8.0. Multiple cycles of feeding were used to grow the cobalt carbonate particles to D0.0 in the primary growth stage. 50 It is 5μm.

[0137] S3: Secondary growth.

[0138] The cobalt carbonate primary growth particles are transferred into a growth reactor. The mixed metal nitrate solution and sodium bicarbonate solution are added to the growth reactor in a parallel flow to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size.

[0139] The secondary growth process involves a pH range of 6.5–8.0, employing a gradient heating method. The initial temperature is 30°C, with the temperature increasing by 4°C with each subsequent feeding cycle. The flow rate of the mixed metal salt solution is 1%V / h. The mass ratio of the mixed metal nitrate solution to the sodium bicarbonate solution is 0.35. The flow rate of the sodium bicarbonate solution feed pump is adjusted accordingly, and the cobalt carbonate particles are fed in a parallel flow to grow to the D-size. 50 It is 6.0 μm.

[0140] S4: Washing, drying, and calcining.

[0141] The cobalt carbonate granule slurry in S3 was fed into a centrifuge and washed with 80°C water for 20 min. After centrifugation and dehydration, it was dried using a flash evaporator to obtain dry, small-particle-size cobalt carbonate doped with rare earth elements. The washed and dried cobalt carbonate was calcined at 900°C for 1 h and sieved (vibrating screen frequency of 3.8 kHz) to obtain small-particle-size cobalt tetroxide doped with rare earth elements and Al.

[0142] Comparative Example 1 The difference between this comparative example and Example 1 is that the temperature was maintained at 42°C throughout the secondary growth process.

[0143] Comparative Example 2 The difference between this comparative example and Example 2 is that the temperature was maintained at 45°C throughout the secondary growth process.

[0144] Comparative Example 3 The difference between this comparative example and Example 1 is that the gradient temperature increase during the secondary growth process is set to 0.5°C for each increase.

[0145] Comparative Example 4 The difference between this comparative example and Example 1 is that the gradient temperature increase during the secondary growth process is set to 5°C each time.

[0146] Comparative Example 5 The difference between this comparative example and Example 1 is that the mixed metal salt solution does not contain aluminum salt.

[0147] Comparative Example 6 The difference between this comparative example and Example 1 is that the aluminum doping content in the modified cobalt tetroxide is 1.523% by mass percentage.

[0148] Comparative Example 7 The difference between this comparative example and Example 1 is that, by mass percentage, the rare earth element doping amounts in the modified cobalt tetroxide are 0.5014% and 0.5003%, respectively.

[0149] Test case Taking the cobalt carbonate and modified cobalt tetroxide prepared in Examples 1-4 and Comparative Examples 1-7 as examples, elemental content testing, morphological observation and particle size testing were carried out.

[0150] The elemental composition was determined using inductively coupled plasma (ICP). Particle size was measured using a laser particle size analyzer. The test results are as follows: Figures 1 to 10 As shown in Tables 1 and 2, in Table 2, QD=(D90-D10) / D50.

[0151] SEM image of cobalt carbonate prepared in Example 1 is shown below. Figure 1 As shown, the SEM image of the modified cobalt tetroxide is as follows. Figure 2 As shown in the figure, the particle size distribution of modified cobalt tetroxide is as follows: Figure 3 As shown. By Figure 2 and Figure 3 It can be seen that the modified cobalt tetroxide has uniform particle size, dense surface, uniform distribution of outer aluminum, and a high tap density (TD) of 2.11 g / cm³. 3 .

[0152] SEM image of cobalt carbonate prepared in Example 2 is shown below. Figure 4 As shown, the SEM image of the modified cobalt tetroxide is as follows. Figure 5 As shown in the figure, the particle size distribution of modified cobalt tetroxide is as follows: Figure 6 As shown. By Figure 5 and Figure 6 It can be seen that the modified cobalt tetroxide has uniform particle size, dense surface, uniform distribution of outer aluminum, and a high tap density (TD) of 2.09 g / cm³. 3 .

[0153] SEM image of cobalt carbonate prepared in Comparative Example 1 is shown below. Figure 7 As shown, the SEM image of the modified cobalt tetroxide is as follows. Figure 8 As shown in the figure, the particle size distribution of modified cobalt tetroxide is as follows: Figure 9 As shown. By Figure 7 and Figure 8 It can be seen that there is a lot of particle breakage, severe surface powdering, and a low tapped density (TD) of 1.67 g / cm³. 3 .

[0154] SEM image of cobalt carbonate prepared in Comparative Example 2 is shown below. Figure 10 As shown, the SEM image of the modified cobalt tetroxide is as follows. Figure 11 As shown in the figure, the particle size distribution of modified cobalt tetroxide is as follows: Figure 12 As shown. By Figure 11 and Figure 12 It can be seen that there is a lot of particle breakage, severe surface powdering, and an even lower tap density (TD) of only 1.54 g / cm³. 3 .

[0155] Table 1. Elemental content and tap density of modified cobalt tetroxide

[0156] Table 2 Elemental tap density and particle size of modified cobalt tetroxide

[0157] As can be seen from Table 1, the modified cobalt tetroxide prepared in Examples 1-4 has a more uniform elemental distribution, higher tap density, and narrower particle size distribution compared to the comparative example.

[0158] In summary, this invention creatively employs a gradient heating combined with wet controlled crystallization technology. By selectively weakening the crystalline order of the inner layer of the material, it precisely controls the crystalline intensity gradient between the inner and outer layers of the particles during precipitation, optimizes the eutectic environment, and promotes the synchronous deposition and lattice embedding of heterogeneous elements such as rare earth and aluminum. Ultimately, this achieves a uniform distribution of these elements in the cobalt tetroxide bulk phase, improves the bonding strength between primary particles of doped cobalt tetroxide, and significantly alleviates the problems of floating powder and broken particles that occur in rare earth doped samples. The resulting modified cobalt tetroxide exhibits a uniform distribution of doped elements, uniform particle size, relatively dense structure, and high mechanical strength. It is not easily broken during calcination and exhibits virtually no surface powder floating phenomenon, which is beneficial for improving the electrochemical performance of downstream products such as lithium cobalt oxide cathode materials.

[0159] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified cobalt tetroxide, characterized in that, The modified cobalt tetroxide is doped with both rare earth elements and aluminum; by mass percentage, the total doping amount of the rare earth elements does not exceed 0.5%, and the doping amount of the aluminum does not exceed 1.2%.

2. The modified cobalt tetroxide according to claim 1, characterized in that, The modified cobalt tetroxide also has at least one of the following characteristics: Feature 1: The modified cobalt tetroxide D 50 The thickness is 3μm to 5μm; Feature 2: Aluminum and rare earth elements are uniformly distributed in the modified cobalt tetroxide; Feature 3: By mass percentage, the modified cobalt tetroxide contains 71%~72% Co, 0.75%~1.20% Al, and 0.1%~0.5% rare earth elements; Feature 4: The tap density of the modified cobalt tetroxide is 2.0 g / cm³. 3 ~2.3g / cm 3 ; Feature 5: The modified cobalt tetroxide D 00 Its thickness ranges from 1.25 μm to 2.5 μm. Feature 6: The modified cobalt tetroxide D 10 Its thickness ranges from 2.1 μm to 3.8 μm. Feature 7: The modified cobalt tetroxide D 90 Its thickness ranges from 5.4 μm to 6.35 μm. Feature 8: The modified cobalt tetroxide D 100 Its thickness ranges from 7.5 μm to 11.5 μm. Feature 9: The QD of the modified cobalt tetroxide is 0.4~0.97, where QD=(D 90 -D 10 ) / D 50 ; Optionally, the modified cobalt tetroxide further contains a metallic element X, which includes at least one of Zr, Mg, Ni and Mn.

3. A method for preparing modified cobalt tetroxide as described in claim 1 or 2, characterized in that, Includes the following steps: A mixed metal salt solution and a carbonate solution are fed into a synthesis reactor with carbonate and water as the base liquid in a parallel flow to carry out a synthesis reaction, thereby obtaining cobalt carbonate seed crystals; wherein, the mixed metal salt solution includes at least soluble rare earth metal salts, cobalt salts and aluminum salts. The mixed metal salt solution and the carbonate solution are added to the synthesis reactor to allow the cobalt carbonate seed crystals to grow in one step, resulting in cobalt carbonate primary growth particles. The cobalt carbonate primary growth particles are transferred into a growth reactor. The mixed metal salt solution and carbonate solution are added to the growth reactor in a co-current feeding manner to mix and react, so that the cobalt carbonate primary growth particles undergo secondary growth until the cobalt carbonate particles reach the preset particle size. The secondary growth process includes multiple gradient heating. The cobalt carbonate particles that have reached the preset particle size are calcined to obtain cobalt tetroxide.

4. The preparation method according to claim 3, characterized in that, The concentration of cobalt ions in the mixed metal salt solution is 80 g / L to 145 g / L, the concentration of aluminum ions is 1.0 g / L to 2.0 g / L, and the concentration of each rare earth element is 0.05 g / L to 0.5 g / L. Optionally, the mixed metal salt solution further contains element X at a concentration of 0.05 g / L to 0.5 g / L; Optionally, the cobalt salt includes at least one of cobalt sulfate, cobalt chloride, and cobalt nitrate; Optionally, the aluminum salt includes at least one of aluminum sulfate, aluminum chloride, and aluminum nitrate; Optionally, the soluble rare earth metal salt includes at least one of yttrium salt, lanthanum salt, cerium salt, ytterbium salt, terbium salt, erbium salt, scandium salt, praseodymium salt, and neodymium salt; And / or, the carbonate solution includes at least one of ammonium bicarbonate solution, ammonium carbonate solution, sodium bicarbonate solution, and sodium carbonate solution; Optionally, the concentration of carbonate in the carbonate solution is 180 g / L to 240 g / L; Optionally, the concentration of carbonate in the bottom solution is 30 g / L to 60 g / L.

5. The preparation method according to claim 3, characterized in that, The synthetic reaction includes at least one of the following characteristics: Feature 10: The reaction temperature for obtaining cobalt carbonate seeds is 20℃~40℃; Feature 11: The reaction pH for obtaining cobalt carbonate seeds is 8.0~9.0; Feature 12: During the reaction process to obtain cobalt carbonate seeds, the flow rate of the mixed metal salt solution is 2%V / h~4%V / h, where V is the volume of the reaction vessel; Feature 13: The cobalt carbonate seed crystals have a particle size of 1.5 μm to 2.5 μm.

6. The preparation method according to claim 3, characterized in that, The primary growth includes at least one of the following characteristics: Feature 14: The temperature for primary growth is 30℃~50℃; Feature 15: The pH value for primary growth is 7.0~8.0; Feature 16: During a single growth process, the flow rate of the mixed metal salt solution is 3%V / h to 5%V / h; Feature 17: At the end of the first growth, the particle size of the cobalt carbonate particles is 3.0 μm to 5.0 μm.

7. The preparation method according to claim 3, characterized in that, The secondary growth includes at least one of the following characteristics: Feature 18: The temperature of the entire secondary growth process is 30℃~60℃; preferably, during the gradient heating process, the temperature is increased by 1℃~4℃ each time; Feature 19: The pH value for secondary growth is 6.5~8.0; Feature 20: During the secondary growth process, the flow rate of the mixed metal salt solution is 1%V / h~5%V / h; Feature 21: The preset particle size of cobalt carbonate particles is 4.0μm~6.0μm.

8. The preparation method according to claim 3, characterized in that, First, the cobalt carbonate particles that have reached the preset particle size are washed and dried, and then calcined. Alternatively, water may be used for washing; Optionally, the washing temperature is 50℃~80℃; Optionally, the washing time is 20 to 50 minutes; Optionally, the calcination temperature is 300℃~900℃.

9. A lithium cobalt oxide cathode material, characterized in that, It is prepared using the modified cobalt tetroxide as described in claim 1 or 2 as a precursor.

10. A lithium-ion battery, characterized in that, Including the lithium cobalt oxide cathode material as described in claim 9.

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