Ternary material, preparation method and application, battery

Abstract

This invention provides a ternary material, its preparation method, its application, and a battery, wherein the chemical formula of the ternary material is Li. x (Ni a Co b Mn 1‑a‑b O2, where 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-a-b>0. By adjusting the cobalt doping amount, the cell volume change rate of the ternary material is controlled to be less than 1% while stabilizing the layered structure. This allows the ternary material to exhibit zero strain characteristics over a wide voltage window, reducing the cell volume change rate of the lithium battery cathode material during charge and discharge. This improves the long-cycle capacity retention rate of the cathode material, enhances its thermal safety stability, and thus extends the lifespan of the lithium battery. Furthermore, compared to lithium cobalt oxide, the reduced cobalt content allows it to replace lithium cobalt oxide in special batteries, significantly lowering the cost of cobalt raw materials while meeting the application requirements of high-pressure compaction.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a ternary material, its preparation method and application, and a battery. Background Technology

[0002] The core of the lithium-ion battery industry is the manufacturing of battery materials. Battery performance largely depends on the performance of the cathode material, among which nickel-cobalt-manganese ternary cathode materials are one of the hot topics in next-generation lithium-ion cathode material research. Ternary cathode material LiNi x Co y Mn z O2(NCM) can take advantage of the complementary electrochemical properties of Ni, Co and Mn, exhibiting a significant ternary synergistic effect, and is considered to be the most commercially valuable cathode material.

[0003] However, ternary cathode materials also have some problems that need to be overcome: (1) The crystal structure of the material is unstable and the crystal structure is easily changed during charging and discharging; (2) The surface structure of the material is unstable and the compatibility between the material and the electrolyte is poor. Due to the presence of HF in the LiPF6 electrolyte, the electrode material is corroded, causing the transition metal ions to dissolve. Moreover, oxygen is easily released and thermal expansion occurs during cycling. It can be seen that the ternary cathode material exhibits cell volume expansion or contraction during charging and discharging, and the cell volume change rate is >1%. The large cell volume change rate will cause microcracks in the cathode material crystal. After repeated charging and discharging, it will gradually develop into grain cracking, which will aggravate the corrosion of the cathode material by the electrolyte and lead to a deeper degree of side reaction on the surface of the cathode material. This will cause the capacity of the lithium battery to show a significant decrease after long-term cycling, which will seriously affect the service life of the lithium battery.

[0004] Therefore, it is urgent to reduce the cell volume change rate of ternary materials and achieve zero strain in order to improve long-term cycling stability and thermal safety. Summary of the Invention

[0005] The technical problem solved by the embodiments of the present invention is to reduce the cell volume change rate of ternary materials, achieve zero strain, and improve the long-term cycling stability and thermal safety of ternary materials.

[0006] To address the above problems, embodiments of the present invention provide a ternary material, wherein the chemical formula of the ternary material is Li. x (Ni a Co b Mn 1-a-b O2, where 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, and 1-ab>0.

[0007] Optionally, the average particle size range of the ternary material is 3-5 μm.

[0008] Optionally, the preparation method of the ternary material includes the following steps:

[0009] Provide lithium compounds and (Ni a Co b Mn 1-a-b OH2 precursor;

[0010] The lithium compound and the precursor are mixed and ground according to the molar ratio of the elements in the chemical formula, and then sintered in a sintering furnace under an oxygen atmosphere at a sintering temperature of 200–900°C for 2–10 h; then the sintering temperature is adjusted to 400–1100°C for 6–25 h; finally, the sintering temperature is adjusted to 200–800°C for 3–15 h.

[0011] The ternary material is obtained by cooling in the furnace, grinding, and sieving.

[0012] Optionally, the (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include:

[0013] Prepare salt solutions, ammonia solutions, and alkaline solutions; the salt solutions are prepared by mixing soluble nickel, cobalt, and manganese compounds in the molar ratio of the elements in the chemical formula, and the concentration of the salt solutions is 0.5–4 mol / L. -1 The ammonia concentration is 0.5–6 mol / L. -1 The concentration of the alkaline solution is 1.5–9.5 mol / L. -1 ;

[0014] The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, with the pH controlled at 8.0 ≤ pH ≤ 11.5, so that a precipitation reaction occurs in the reaction vessel;

[0015] The precipitate was removed, washed, filtered, and dried to obtain the (Ni) a Co b Mn 1-a-b OH2 precursor.

[0016] Optionally, the nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a nickel-containing metal oxide; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a cobalt-containing metal oxide; and the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a manganese-containing metal oxide.

[0017] Optionally, the oxygen atmosphere contains oxygen and has an oxygen volume content of 21% or more.

[0018] Optionally, the drying temperature of the precursor is ≤180℃.

[0019] Optionally, the lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide.

[0020] Optionally, the preparation method of the ternary material includes the following steps:

[0021] Provide cobalt sources, lithium compounds and Li X (Ni A Co B Mn 1-A-B )OH2 precursor, 1.0≤X≤1.15, B<0.4, 1-AB>0, wherein the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide or a metal oxide containing cobalt;

[0022] According to the molar ratio of the elements in the chemical formula (Ⅰ), the cobalt source, the lithium compound, and the Li X (Ni A Co B Mn 1-A-B The OH2 precursor was mixed, ground, and then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200–900℃ for 2–10 h. The sintering temperature was then adjusted to 400–1100℃ for 6–25 h. Finally, the sintering temperature was adjusted to 200–800℃ for 3–15 h.

[0023] The ternary material is obtained by cooling in the furnace, grinding, and sieving.

[0024] Optionally, the preparation method of the ternary material includes the following steps:

[0025] According to the molar ratio of the elements in the chemical formula (Ⅰ), lithium compound, nickel compound, cobalt compound and manganese compound are mixed to obtain mixture A. Mixture A is mixed with citric acid in a certain proportion to obtain mixture B. Mixture B is dried, ground and sintered to obtain the ternary material.

[0026] This invention provides a method for preparing a ternary material, comprising:

[0027] Provides a lithium compound and a precursor, wherein the precursor is (Ni a Co b Mn 1-a-b OH2 precursor or LiX (Ni A Co B Mn 1-A-B OH2 precursor, wherein 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-ab>0, 1.0≤X≤1.15, B<0.4, 1-AB>0; according to chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, the lithium compound and the (Ni) a Co b Mn 1-a-b )OH2 precursors are mixed and ground; or, according to the chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, including the cobalt source, the lithium compound, and the Li X (Ni A Co B Mn 1-A-B The OH2 precursor is mixed and ground; the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a metal oxide containing cobalt.

[0028] The material is then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200–900°C for 2–10 hours. The sintering temperature is then adjusted to 400–1100°C for 6–25 hours. Finally, the sintering temperature is adjusted to 200–800°C for 3–15 hours. After cooling in the furnace, the material is ground and sieved to obtain the ternary material.

[0029] Optionally, the (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include:

[0030] Prepare salt solutions, ammonia solutions, and alkaline solutions; the salt solutions are prepared by mixing soluble nickel, cobalt, and manganese compounds in the molar ratio of the elements in the chemical formula (I), and the concentration of the salt solutions is 0.5–4 mol / L. -1 The ammonia concentration is 0.5–6 mol / L. -1 The concentration of the alkaline solution is 1.5–9.5 mol / L. -1 ;

[0031] The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, controlling the pH to be 8.0 ≤ pH ≤ 11.5, to induce a precipitation reaction in the reaction vessel; the precipitate is then removed, washed, filtered, and dried to obtain the (Ni) solution.a Co b Mn 1-a-b OH2 precursor.

[0032] Optionally, the lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide; the nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a nickel-containing metal oxide; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a cobalt-containing metal oxide; and the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a manganese-containing metal oxide.

[0033] The ternary material provided in this invention can be used as a cathode material for lithium-ion batteries.

[0034] To address the aforementioned problems, embodiments of the present invention provide a battery comprising: a positive electrode sheet, the positive electrode sheet comprising a positive current collector and a positive active layer bonded to the surface of the positive current collector, wherein the positive electrode material contained in the positive active layer is the aforementioned ternary material.

[0035] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0036] The ternary material provided in this embodiment of the invention has the chemical formula Li. x (Ni a Co b Mn 1-a-b O2, where 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-ab>0. By adjusting the cobalt doping amount, the cell volume change rate of the ternary material is controlled to be less than 1% while stabilizing the layered structure. This allows the ternary material to exhibit zero strain characteristics over a wide voltage window, reducing the cell volume change rate of the lithium battery cathode material during charge and discharge. This improves the long-cycle capacity retention rate of the cathode material, enhances its thermal safety stability, and thus extends the lifespan of the lithium battery. Furthermore, compared to lithium cobalt oxide, the reduced cobalt content allows it to replace lithium cobalt oxide in special batteries, significantly lowering the cost of cobalt raw materials while meeting the application requirements of high-pressure compaction. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 The Li obtained in Example 1 of this invention 1.05 (Ni 0.35 Co 0.4 Mn 0.25 SEM images of O2 ternary materials;

[0039] Figure 2 The Li obtained in Example 2 of this invention 1.05 (Ni 0.1 Co 0.8 Mn 0.1 SEM images of O2 ternary materials;

[0040] Figure 3 The Li obtained in Example 3 of this invention 1.05 (Ni 0.25 Co 0.6 Mn 0.15 SEM images of O2 ternary materials;

[0041] Figure 4 The Li obtained in Comparative Example 1 1.05 (Ni 1 / 3 Co 1 / 3 Mn 1 / 3 SEM images of O2 ternary materials;

[0042] Figure 5 The Li obtained in Comparative Example 2 1.05 (Ni 0.6 Co 0.2 Mn 0.2 SEM images of O2 ternary materials;

[0043] Figure 6 The XRD patterns of Embodiments 1, 3 and Comparative Example 2 of the present invention are shown below;

[0044] Figure 7 The cyclic test spectra of the button cells of Examples 1-3 and Comparative Example 2 of this invention are 3.0-4.3V, 1C (activated for 2 cycles at 0.1C).

[0045] Figure 8 The in-situ XRD pattern and cell volume change spectrum of the coin cell battery at 3.0-4.6V and 0.1C during the first charge cycle of the present invention (Example 3) are shown. Detailed Implementation

[0046] As can be seen from the background technology, the long-cycle stability and thermal safety of ternary materials need to be improved.

[0047] Analysis reveals that currently used nickel-rich NCM materials experience cell volume shrinkage during charging and subsequent expansion during discharging. After multiple cycles, this repeated expansion / contraction, with cell volume changes exceeding 1%, leads to microcracks in the cathode material crystals. This affects electron transport in the active particles. Furthermore, the renewed contact between these newly formed microcracks and the electrolyte increases transition metal dissolution, exacerbating electrolyte corrosion of the cathode material and intensifying surface side reactions. Additionally, the formation of a new SEI film due to electrolyte decomposition increases lithium-ion transport resistance and accelerates capacity decay, severely impacting the lifespan of lithium batteries. Similarly, during charging, the layered crystalline structure transforms into a spinel structure due to oxygen loss, releasing significant heat, which is detrimental to battery safety. Moreover, with increasing nickel content, lattice volume expansion during charging and discharging increases, while thermal stability decreases. Therefore, how to reduce the cell volume change rate of ternary materials and achieve zero strain in order to improve the long-term cycling stability and thermal safety of ternary materials has become a technical problem that urgently needs to be solved by those skilled in the art.

[0048] Nickel-rich NCM materials refer to nickel-cobalt-manganese ternary cathode materials, in which the nickel content is greater than or equal to 50%.

[0049] To address the above problems, embodiments of the present invention provide a ternary material, wherein the chemical formula of the ternary material is Li. x (Ni a Co b Mn 1-a-b )O2(Ⅰ), where 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-ab>0.

[0050] It should be noted that zero strain as described in this article refers to a cell volume change rate of no more than 1% for ternary materials. The chemical formula is Li. x (Ni a Co b Mn 1-a-b The ternary material of O2(Ⅰ) can be regarded as a zero-strain ternary material.

[0051] In a specific example, the chemical formula of the ternary material can be Li 1.05 (Ni 0.35 Co 0.4 Mn 0.25 O2, Li 1.05 (Ni 0.25 Co 0.5 Mn0.25 O2, Li 1.05 (Ni 0.2 Co 0.5 Mn 0.3 O2, Li 1.05 (Ni 0.25 Co 0.6 Mn 0.15 O2, Li 1.05 (Ni 0.15 Co 0.6 Mn 0.25 O2, Li 1.05 (Ni 0.15 Co 0.7 Mn 0.15 O2, Li 1.05 (Ni 0.1 Co 0.8 Mn 0.1 )O2.

[0052] By adjusting the cobalt doping amount, the cell volume change rate of the ternary material is controlled to be less than 1% while stabilizing the layered structure. This allows the ternary material to exhibit zero strain characteristics over a wide voltage window, reducing the cell volume change rate of the lithium battery cathode material during charge and discharge. This improves the long-cycle capacity retention rate of the cathode material, enhances its thermal safety stability, and thus extends the lifespan of the lithium battery. Furthermore, compared to lithium cobalt oxide, the reduced cobalt content allows it to replace lithium cobalt oxide in special batteries, significantly lowering the cost of cobalt raw materials while meeting the application requirements of high-pressure compaction.

[0053] The ternary material provided in this invention has uniform particle size, is spherical or near-spherical, and has an average particle size between 3 and 5 μm. The 3-5 μm spherical particles make it promising for fast charging applications.

[0054] The preparation method of the ternary material includes one or more of the following methods combined: (1) coprecipitation method; (2) high temperature solid phase method; (3) hydrothermal method; (4) sol-gel method.

[0055] In one embodiment, a ternary material is prepared by first using a co-precipitation method to prepare a precursor, and then using a lithium source for high-temperature solid-state sintering. By using the co-precipitation method to prepare the ternary material precursor, multi-element co-doping elements are introduced in situ, and the multi-element co-doping elements are uniformly distributed in the bulk phase of the precursor, achieving atomic-level uniform doping and thus improving the doping effect of the multi-element co-doping elements.

[0056] Specifically, the preparation method of ternary materials includes the following steps:

[0057] Step 1: Provide lithium compound and (Ni a Cob Mn 1-a-b OH2 precursor; wherein, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-ab>0;

[0058] In one embodiment, the (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include:

[0059] Preparation of salt solutions, ammonia solutions, and alkaline solutions; the salt solutions are prepared according to the chemical formula (Ni a Co b Mn 1-a-b The salt solution in OH₂ is a mixture of soluble nickel, cobalt, and manganese compounds in a molar ratio, with a concentration of 0.5–4 mol / L. -1 The ammonia concentration is 0.5–6 mol / L. -1 The concentration of the alkaline solution is 1.5–9.5 mol / L. -1 ;

[0060] The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, with the pH controlled at 8.0 ≤ pH ≤ 11.5, so that a precipitation reaction occurs in the reaction vessel;

[0061] The precipitate was removed, washed, filtered, and dried at a temperature ≤180℃ to obtain the (Ni) a Co b Mn 1-a-b OH2 precursor.

[0062] The nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a metal oxide containing nickel; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a metal oxide containing cobalt; the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a metal oxide containing manganese.

[0063] Alkaline solutions can be alkaline compounds such as sodium hydroxide (NaOH) that do not introduce impurities.

[0064] Of course, in other embodiments, there is no limitation (Ni) a Co b Mn 1-a-b Preparation method of OH2 precursor.

[0065] Step 2: According to the chemical formula Li x (Ni a Cob Mn 1-a-b The molar ratio of elements in O2, the lithium compound and the (Ni) a Co b Mn 1-a-b The OH2 precursor was mixed, ground, and then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200–900℃ for 2–10 h. The sintering temperature was then adjusted to 400–1100℃ for 6–25 h. Finally, the sintering temperature was adjusted to 200–800℃ for 3–15 h.

[0066] In one specific example, an oxygen atmosphere refers to a gas mixture containing oxygen with a volume content of 21% or more.

[0067] The lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide.

[0068] Step 3: Cool in the furnace, grind, and sieve to obtain the ternary material.

[0069] Of course, in other embodiments, the preparation method of the ternary material is not limited, as long as the ternary material with the given structural formula can be obtained, it is acceptable.

[0070] In an alternative embodiment, a precursor that does not satisfy the molar ratio of chemical formula (I) can be prepared in advance, for example, (Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )OH2, and add a new cobalt source (e.g., cobalt hydroxide) before sintering to ensure that the nickel, cobalt and manganese elements in the final ternary material meet the molar ratio in chemical formula (Ⅰ).

[0071] Specifically, the preparation method of ternary materials may also include the following steps: providing a cobalt source, a lithium compound, and Li. X (Ni A Co B Mn 1-A-B )OH2 precursor, 1.0≤X≤1.15, B<0.4, 1-AB>0, wherein the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide or a metal oxide containing cobalt;

[0072] According to the chemical formula Li x (Ni a Co b Mn 1-a-b The molar ratio of elements in O2, including the cobalt source, the lithium compound, and the Li... X (NiA Co B Mn 1-A-B The OH2 precursor is mixed and ground to ensure that the nickel, cobalt, and manganese elements in the final ternary material meet the requirements of the chemical formula Li. x (Ni a Co b Mn 1-a-b The molar ratio of O2 is determined, and then the mixture is placed in a sintering furnace under an oxygen atmosphere for sintering at a temperature of 200–900℃ for 2–10 h. The sintering temperature is then adjusted to 400–1100℃ for 6–25 h. Finally, the sintering temperature is adjusted to 200–800℃ for 3–15 h. After cooling in the furnace, the mixture is ground and sieved to obtain the ternary material.

[0073] Alternatively, in one embodiment, the precursor may not be prepared in advance, but the ternary material may be obtained directly by sintering after mixing the components in the specified molar ratio using a sol-gel method. For example, lithium compound, nickel compound, cobalt compound, and manganese compound are mixed according to the molar ratio of the elements in the chemical formula (I) to obtain A. Mixture A is then mixed with citric acid in a specified ratio to obtain mixture B. Mixture B is then dried, ground, and sintered to obtain the ternary material.

[0074] Specifically, with Li 1.05 (Ni 0.35 Co 0.4 Mn 0.25 Taking O2 ternary materials as an example, lithium carbonate, nickel acetate, cobalt acetate, and manganese acetate are combined according to the chemical formula Li 1.05 (Ni 0.35 Co 0.4 Mn 0.25 Mixture A is prepared by mixing O2 in a specific molar ratio. Mixture A is then mixed with citric acid at a molar ratio of 1:2.05 to obtain mixture B. Mixture B is further prepared by adding an appropriate amount of distilled water and then mixing thoroughly in a ball mill at 300 rpm for 5 hours. The homogeneous mixture B is then removed and dried in a drying oven at 120°C for 24 hours. The dried raw material mixture B is then ground into a fine powder. The fine powder mixture B is then sintered in a sintering furnace to obtain Li. 1.05 (Ni 0.35 Co 0.4 Mn 0.25 O2 ternary materials.

[0075] In other embodiments, the lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide; the nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a nickel-containing metal oxide; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a cobalt-containing metal oxide; and the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a manganese-containing metal oxide.

[0076] This invention also provides a method for preparing a ternary material, comprising:

[0077] Provides a lithium compound and a precursor, wherein the precursor is (Ni a Co b Mn 1-a-b OH2 precursor or Li X (Ni A Co B Mn 1-A-B OH2 precursor, wherein 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b≤0.8, 1-ab>0, 1.0≤X≤1.15, B<0.4, 1-AB>0; according to chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, the lithium compound and the (Ni) a Co b Mn 1-a-b )OH2 precursors are mixed and ground; or, according to the chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, including the cobalt source, the lithium compound, and the Li X (Ni A Co B Mn 1-A-B The OH2 precursor is mixed and ground; the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a metal oxide containing cobalt.

[0078] The material is then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200–900°C for 2–10 hours. The sintering temperature is then adjusted to 400–1100°C for 6–25 hours. Finally, the sintering temperature is adjusted to 200–800°C for 3–15 hours. After cooling in the furnace, the material is ground and sieved to obtain the ternary material.

[0079] The (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include:

[0080] Prepare salt solutions, ammonia solutions, and alkaline solutions; the salt solutions are prepared by mixing soluble nickel, cobalt, and manganese compounds in the molar ratio of the elements in the chemical formula (I), and the concentration of the salt solutions is 0.5–4 mol / L. -1 The ammonia concentration is 0.5–6 mol / L. -1 The concentration of the alkaline solution is 1.5–9.5 mol / L. -1 ;

[0081] The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, controlling the pH to be 8.0 ≤ pH ≤ 11.5, to induce a precipitation reaction in the reaction vessel; the precipitate is then removed, washed, filtered, and dried to obtain the (Ni) solution. a Co b Mn 1-a-b OH2 precursor.

[0082] The lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide; the nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a nickel-containing metal oxide; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a cobalt-containing metal oxide; the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a manganese-containing metal oxide.

[0083] The present invention also provides the application of the ternary material in cathode materials.

[0084] This invention also provides a battery, including essential battery components such as a casing, a core formed from a positive electrode sheet / separator / negative electrode sheet disposed within the casing, and an electrolyte. The positive electrode sheet includes a positive current collector and a positive active layer bonded to the surface of the positive current collector, wherein the positive electrode material contained in the positive active layer is the aforementioned ternary material.

[0085] In a specific embodiment, the battery can be a lithium-ion battery or a lithium metal battery, etc. Thus, since the battery uses the aforementioned ternary material as the positive electrode material, it exhibits excellent long-cycle performance and thermal stability.

[0086] The following detailed description of the ternary material, preparation method, application, and battery of the present invention, in conjunction with specific embodiments and comparative examples, provides further details.

[0087] Example 1

[0088] (1)(Ni 0.35 Co 0.4 Mn 0.25 Preparation of OH2 precursor: Nickel sulfate, cobalt sulfate, and manganese sulfate were mixed in a specific molar ratio to prepare solution A, with a concentration of 2 mol / L. -1 ammonia concentration 4 mol L -1 Sodium hydroxide solution concentration 8 mol / L -1 All solutions were prepared using deionized water as the solvent. Solution A, ammonia, and sodium hydroxide solution were then added to the reactor via a peristaltic pump. An automatic control system maintained the feed ratio of solution A to ammonia at 4:1 and automatically adjusted the feed rate of sodium hydroxide, thereby controlling the pH inside the reactor to 9.8 ± 0.2. The stirring speed of the reactor was controlled at 600 rpm. -1 The precipitation reaction was stopped after 8.5 hours. The co-precipitated solid-liquid mixture B was removed from the reactor and washed repeatedly with deionized water 5-6 times. The liquid portion of the solid-liquid mixture B was removed by vacuum filtration to obtain the (Ni) to be dried. 0.35 Co 0.4 Mn 0.25 )OH2 precursor. The precursor to be dried was placed in a drying oven and heated at 110℃ for 12 hours to dry thoroughly, then removed to obtain (Ni) 0.35 Co 0.4 Mn 0.25 OH2 precursor.

[0089] (2) (Ni) 0.35 Co 0.4 Mn 0.25 The OH2 precursor and lithium hydroxide were mixed at a molar ratio of 1:1.05 and added at 2000 rpm. -1 After mixing in a high-speed mixer for 30 minutes, the mixture is placed in a sintering furnace for sintering. The sintering atmosphere in the furnace contains oxygen with an oxygen content of ≥21%, and the heating rate is 5℃ / min. -1 The cooling rate is 1℃ / min. -1The sintering temperature was 550±10℃ for 6 hours, then the temperature was further increased to 850±10℃ for 12 hours, after which the temperature was lowered to 450±10℃ and heating was stopped. The sample was removed after allowing it to cool naturally to room temperature inside the sintering furnace. Li was obtained by grinding and sieving. 1.05 (Ni 0.35 Co 0.4 Mn 0.25 O2 material.

[0090] (3) Li 1.05 (Ni 0.35 Co 0.4 Mn 0.25 O2 material: Conductive agent (Super P:KS-6 = 1:1): Binder (8% PVDF) are mixed at a mass ratio of 80:10:10, with an appropriate amount of dispersant (NMP) added. The mixture is then homogenized at 2000 rpm. -1 After mixing at a speed of 1000 rpm for 15 minutes, then at 1000 rpm... -1 Defoaming was performed at a high speed for 5 minutes to obtain the positive electrode slurry. The positive electrode slurry was then coated on a coating machine with an electrode thickness of 200 μm. Aluminum foil was used as the current collector for the positive electrode material. The coated electrode was then transferred to a forced-air drying oven and dried at 80°C for 1 hour. After drying, the electrode was placed in a vacuum drying oven and stored under vacuum at 120°C for 12 hours. The completely dried positive electrode was then compacted using a roller press and cut into round sheets (electrode diameter Ф12 mm) for later use.

[0091] (4) Assemble the positive electrode into a button cell, using lithium foil as the negative electrode, 1.0 mol / L LiPF6 (EC:DEC:EMC = 1:1:1) as the electrolyte, and Celgard 2500 as the separator. Assemble the battery in an argon-atmospheric glove box, placing the positive electrode shell, positive electrode, separator, electrolyte, negative electrode, electrolyte, gasket, arched gasket, and negative electrode shell in sequence. Seal the battery using a hydraulic sealing machine. Wipe away any residual electrolyte on the battery casing, allow it to stand for 4 hours, and then conduct relevant tests. The charge / discharge voltage range is 3.0–4.3V. Charge / discharge experiments are conducted at 1C rate (2 cycles of activation at 0.1C) to test the battery cycle performance. The measured cycle performance curves are shown below. Figure 7 As shown.

[0092] Example 2

[0093] The difference from Example 1 lies in the different amounts of nickel, cobalt, and manganese in the precursor: (Ni 0.1 Co 0.8 Mn 0.1 Preparation of OH2 precursor: Nickel sulfate, cobalt sulfate, and manganese sulfate were prepared into a solution according to the molar ratio. The remaining parts and parts (2) to (4) were the same as in Example 1, and Li was finally obtained.1.05 (Ni 0.1 Co 0.8 Mn 0.1 O2 material.

[0094] Example 3

[0095] The difference from Example 1 lies in the different amounts of nickel, cobalt, and manganese in the precursor: (Ni 0.25 Co 0.6 Mn 0.15 Preparation of OH2 precursor: Nickel sulfate, cobalt sulfate, and manganese sulfate were prepared into a solution according to the molar ratio. The remaining parts and parts (2) to (4) were the same as in Example 1, and Li was finally obtained. 1.05 (Ni 0.25 Co 0.6 Mn 0.15 O2 material.

[0096] Comparative Example 1

[0097] Li was prepared according to the method for preparing the precursor in Example 1(1). 1.05 (Ni 1 / 3 Co 1 / 3 Mn 1 / 3 Following the OH2 (i.e., NCM111) precursor, Li was further prepared according to (2) to (4) in Example 1. 1.05 (Ni 1 / 3 Co 1 / 3 Mn 1 / 3 OH2 material, which is one of the commercially available ternary cathode materials.

[0098] Comparative Example 2

[0099] Ni was prepared according to the method for preparing the precursor in Example 1(1). 0.6 Co 0.2 Mn 0.2 Following the OH2 (i.e., NCM 622) precursor, Li was further prepared according to (2) to (4) in Example 1. 1.05 (Ni 0.6 Co 0.2 Mn 0.2 OH2 material is one of the conventional nickel-rich ternary cathode materials and has been commercialized.

[0100] Performance testing

[0101] The surface morphology of the ternary materials in Examples 1-3 and Comparative Examples 1-2 was observed using a scanning electron microscope (HITACHI SU3800, 5kV, Japan). The test results are shown in [Figure number missing]. Figure 1-5As shown in the figure, the ternary material has uniform particle size, is spherical or near-spherical, and has an average particle size between 3 and 5 μm. The 3–5 μm spherical particles make it a promising candidate for fast charging applications.

[0102] like Figure 6 The XRD patterns of the ternary materials in Examples 1 and 3 show that there is no obvious peak shift or other impurity peaks, indicating that the ternary materials provided in the embodiments of the present invention have good structural stability.

[0103] The battery cycle performance was tested with a charge / discharge voltage range of 3.0–4.3V. Cycle tests were performed at 1C (the first two cycles were 0.1C). The test results are as follows: Figure 7 As shown. By Figure 7 It can be seen that after 50 cycles, the capacity retention rate of Comparative Example 2 is 31%, while the capacity retention rate of the embodiments of this application is above 77%, the capacity retention rate of Example 2 is 91.2%, and the capacity retention rate of Example 3 is as high as 97.9%. It is evident that the battery made of ternary material provided in this application can exhibit better charge-discharge capacity and cycle stability.

[0104] Depend on Figure 8 It can be seen that the cell volume change rate of Example 3 is 0.57%, which further indicates that the ternary material provided by the present invention has zero strain characteristics under a wide voltage window, reduces the cell volume change rate of the lithium battery cathode material during charging and discharging, can improve the long cycle capacity retention rate of the cathode material, improve the thermal safety stability of the cathode material, and thus extend the service life of the lithium battery.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A ternary material, characterized in that, The chemical formula of the ternary material is Li x (Ni a Co b Mn 1-a-b )O2 (I), where 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b<0.6, 1-ab > 0.

2. The ternary material as described in claim 1, characterized in that, The average particle size range of the ternary material is 3-5 μm.

3. The ternary material as described in claim 1 or 2, characterized in that, The preparation method of the ternary material includes the following steps: Provide lithium compounds and (Ni a Co b Mn 1-a-b OH2 precursor; According to the molar ratio of the elements in the chemical formula (I), the lithium compound and the (Ni) a Co b Mn 1-a-b The OH2 precursor was mixed, ground, and then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200-900℃ for 2-10 h. The sintering temperature was then adjusted to 400-1100℃ for 6-25 h. Finally, the sintering temperature was adjusted to 200-800℃ for 3-15 h. The ternary material is obtained by cooling in the furnace, grinding, and sieving.

4. The ternary material as described in claim 3, characterized in that, The (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include: Prepare a salt solution, an ammonia solution, and an alkaline solution; the salt solution is prepared by mixing soluble nickel, cobalt, and manganese compounds in the molar ratio of the elements in the chemical formula (I), and the concentration of the salt solution is 0.5 ~ 4 mol L. -1 The ammonia concentration is 0.5 ~ 6 mol L. -1 The alkaline solution concentration is 1.5~9.5 mol / L. -1 ; The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, with the pH controlled at 8.0 ≤ pH ≤ 11.5, so that a precipitation reaction occurs in the reaction vessel; The precipitate was removed, washed, filtered, and dried to obtain the (Ni) a Co b Mn 1-a-b OH2 precursor.

5. The ternary material as described in claim 4, characterized in that, The nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a metal oxide containing nickel; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a metal oxide containing cobalt; the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a metal oxide containing manganese.

6. The ternary material as described in claim 3, characterized in that, The oxygen atmosphere is one that contains oxygen and has an oxygen volume content of 21% or more.

7. The ternary material as described in claim 4, characterized in that, The drying temperature is ≤180℃.

8. The ternary material as described in claim 4, characterized in that, The lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide.

9. The ternary material as described in claim 1 or 2, characterized in that, The preparation method of the ternary material includes the following steps: Provide cobalt sources, lithium compounds and Li X (Ni A Co B Mn 1-A-B )OH2 precursor, 1.0≤X≤1.15, B<0.4, 1-AB>0, wherein the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide or a metal oxide containing cobalt; According to the molar ratio of the elements in the chemical formula (I), the cobalt source, the lithium compound, and the Li X (Ni A Co B Mn 1-A-B The OH2 precursor was mixed, ground, and then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200-900℃ for 2-10 h. The sintering temperature was then adjusted to 400-1100℃ for 6-25 h. Finally, the sintering temperature was adjusted to 200-800℃ for 3-15 h. The ternary material is obtained by cooling in the furnace, grinding, and sieving.

10. The ternary material as described in claim 1 or 2, characterized in that, The preparation method of the ternary material includes the following steps: According to the molar ratio of the elements in the chemical formula (I), lithium compound, nickel compound, cobalt compound and manganese compound are mixed to obtain A. Mixture A is mixed with citric acid in a certain proportion to obtain mixture B. Mixture B is dried, ground and sintered to obtain the ternary material.

11. A method for preparing a ternary material, characterized in that, include: Provides a lithium compound and a precursor, wherein the precursor is (Ni a Co b Mn 1-a-b OH2 precursor or Li X (Ni A Co B Mn 1-A-B OH2 precursor, wherein 1.0≤x≤1.15, 0.1≤a≤0.35, 0.4≤b<0.6, 1-ab>0, 1.0≤X≤1.15, B<0.4, 1-AB>0; according to chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, the lithium compound and the (Ni) a Co b Mn 1-a-b )OH2 precursors are mixed and ground; or, according to the chemical formula (Ni a Co b Mn 1-a-b The molar ratio of elements in OH2, including the cobalt source, the lithium compound, and the Li X (Ni A Co B Mn 1-A-B The OH2 precursor is mixed and ground; the cobalt source includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a metal oxide containing cobalt. The ground mixture was then sintered in a sintering furnace under an oxygen atmosphere at a temperature of 200–900°C for 2–10 h. The sintering temperature was then adjusted to 400–1100°C for 6–25 h. Finally, the sintering temperature was adjusted to 200–800°C for 3–15 h. After cooling in the furnace, the mixture was ground and sieved to obtain the ternary material.

12. The method for preparing ternary materials as described in claim 11, characterized in that, The (Ni) a Co b Mn 1-a-b The preparation steps of the OH2 precursor include: Preparation of salt solutions, ammonia solutions, and alkaline solutions; the salt solutions are prepared according to the chemical formula (Ni a Co b Mn 1-a-b The salt solution in OH₂ is a mixture of soluble nickel, cobalt, and manganese compounds in a molar ratio, with a concentration of 0.5–4 mol / L. -1 The ammonia concentration is 0.5 ~ 6 mol L. -1 The alkaline solution concentration is 1.5~9.5 mol / L. -1 ; The salt solution, the ammonia solution, and the alkaline solution are added to a reaction vessel to carry out a chemical reaction, controlling the pH to be 8.0 ≤ pH ≤ 11.5, to induce a precipitation reaction in the reaction vessel; the precipitate is then removed, washed, filtered, and dried to obtain the (Ni) solution. a Co b Mn 1-a-b OH2 precursor.

13. The method for preparing ternary materials as described in claim 12, characterized in that, The lithium compound includes at least one of lithium sulfate, lithium acetate, lithium carbonate, lithium nitrate, lithium dihydrogen phosphate, lithium phosphate, lithium oxalate, lithium fluoride, lithium chloride, and lithium hydroxide; the nickel compound includes nickel sulfate, nickel acetate, nickel carbonate, nickel nitrate, nickel phosphate, nickel oxalate, nickel fluoride, nickel chloride, nickel hydroxide, or a nickel-containing metal oxide; the cobalt compound includes cobalt sulfate, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt phosphate, cobalt oxalate, cobalt fluoride, cobalt chloride, cobalt hydroxide, or a cobalt-containing metal oxide; the manganese compound includes manganese sulfate, manganese acetate, manganese carbonate, manganese nitrate, manganese phosphate, manganese oxalate, manganese fluoride, manganese chloride, manganese hydroxide, or a manganese-containing metal oxide.

14. The application of a ternary material as described in any one of claims 1-10 in cathode materials.

15. A battery, characterized in that, include: A positive electrode sheet, the positive electrode sheet comprising a positive current collector and a positive active layer bonded to the surface of the positive current collector, wherein the positive material contained in the positive active layer is a ternary material as described in any one of claims 1-10.

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