Single-crystal manganese-based lithium battery cathode material and preparation method thereof

Abstract

The application discloses a single-crystal manganese-based lithium battery positive electrode material and a preparation method thereof, and belongs to the technical field of lithium battery positive electrode materials. The specific capacity of the material is improved, and the cycle life of the material is prolonged through the method of composite metal ion synergic doping and anion-cation synergic doping, control of material reaction temperature and reaction time, and addition of a high-specific-capacity lithium-rich compound. The single-crystal material has the remarkable advantages of high specific capacity, large battery pole piece compaction density, long normal-temperature cycle life, good rate discharge, good high-temperature cycle and power storage performance, and the like. The preparation method is simple, and industrialized production is easy to realize. Multiple products can be formed, and different market demands can be met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium battery positive electrode materials, and particularly relates to a single-crystal manganese-based lithium battery positive electrode material and a preparation method thereof. BACKGROUND

[0002] The performance of a lithium battery mainly depends on a positive electrode material, a negative electrode material, an electrolyte and a separator, wherein the positive electrode material is the most critical part, and the research and development of the positive electrode material has become a key to the development of lithium ions. An ideal positive electrode material should have the following characteristics: (1) a high and stable discharge platform, and no reaction with an electrolyte; (2) a stable crystal structure, a small change in the oxidation-reduction potential in the charging and discharging process, good cycle performance and a stable discharge platform; (3) a high lithium ion diffusion coefficient, which can reduce the degree of polarization, reduce energy loss and obtain a faster charging and discharging; and (4) a large Gibbs free energy in the lithium ion reaction, so as to reduce the energy loss caused by polarization.

[0003] The single-crystal manganese-based lithium battery positive electrode material is an upgraded version of a spinel lithium manganate (LiMn2O4) positive electrode material. Although the pure lithium manganate positive electrode material has high safety and high-rate discharge capacity, and is low in price, its low specific capacity and poor cycle performance, especially high-temperature cycle performance, greatly limit its application. Although the cycle performance has been improved to some extent through research in the past ten years or so, the high-temperature cycle performance has not been well solved, and it has seriously lagged behind the development and application of nickel-cobalt-manganese lithium manganate, cobalt lithium manganate and iron lithium phosphate.

[0004] Structural and chemical reasons cause the capacity attenuation of LiMn2O4 at room temperature, and the manganese dissolution caused by HF in the electrolyte at high temperature will be intensified, and the chemical effect will intensify the structural effect, resulting in rapid capacity attenuation at high temperature. To improve the high-temperature cycle performance of the spinel LiMn2O4, the bulk phase, the surface phase and the crystal primary particle size of the spinel must be started, the structural change thereof is inhibited by stabilizing the bulk phase, the chemical change thereof is prevented by improving the surface phase, and the high-temperature cycle performance is improved by adjusting the synthesis conditions to change the crystal morphology, the surface area size of the spinel and to reduce the manganese dissolution rate.

[0005] Patent application No. CN111640937A discloses a preparation method of a single-crystal lithium manganate material. In the method, a manganese compound and sodium sulfate are weighed according to a required ratio, added to deionized water, stirred for 1-10 hours, reacted at 100-150 DEG C for 10-15 hours, filtered and collected after cooling, washed with deionized water for 1-5 times, and dried to obtain a β-MnO2 precursor; the obtained β-MnO2 precursor, a lithium source and a compound of a doping element M are mixed in a certain proportion, sintered to obtain a finished product, and the molecular formula of the finished product is Li 1+a Mn2-a-b M b O4, 0≤a≤0.2, 0<b≤0.2, wherein the doping element M is one or more of Al, Ti, Zr, Si, Zn, Mg, Ga, B, Cr, Co, Y. The invention needs to prepare the beta-MnO2 precursor by a liquid phase method, and a large amount of ion water is needed for washing during preparation. If the wastewater generated during the process is not properly treated, it will pollute the environment.

[0006] Patent application with publication number CN113285068A discloses a single crystal lithium manganate positive electrode material and a preparation method thereof. The preparation method comprises the following steps: first, uniformly mixing a compound of Li, a compound of Mn and a compound containing a doping element M; performing first sintering at 650-950 DEG C, cooling, crushing and sieving to obtain single crystal lithium manganate primary sintered material; second, performing surface coating on the single crystal lithium manganate primary sintered material with a compound containing a coating element N to obtain coated single crystal lithium manganate primary sintered material; third, performing second sintering on the coated single crystal lithium manganate primary sintered material at 300-800 DEG C, cooling and crushing to obtain the single crystal lithium manganate positive electrode material. The single crystal lithium manganate positive electrode material prepared by the invention has good structural stability during charge-discharge cycle, excellent high-temperature and normal-temperature cycle performance and high-temperature storage performance, but the capacity of the button cell test is not high, and the normal-temperature capacity under a discharge current of 0.1 C at a working voltage of 3.0-4.3 V is only between 106.2-110.5 mAh / g.

[0007] Patent application with publication number CN111362307A discloses a preparation method of a single crystal lithium manganate positive electrode material for lithium ion batteries. The method comprises the following six steps: step A, ball-milling a small particle manganese source, lithium carbonate and an additive according to a proportion; step B, sintering the ball-milled material at a low temperature; step C, ball-milling the low-temperature sintered material, fine crystal lithium manganate seed crystals and a sintering aid according to a proportion; step D, sintering the ball-milled mixture containing fine crystal lithium manganate seed crystals; step E, crushing the high-temperature sintered material, then adding a coating agent for coating sintering; and step F, preparing the finished product through process classification, magnetic removal, batch mixing and packaging and other post-processing procedures. Compared with the traditional process, the preparation method of the invention is simple and more environmentally friendly, and the obtained lithium manganate product has high capacity and long service life, but the method cannot effectively improve the high-temperature cycle performance and storage performance of the material. SUMMARY

[0008] Based on the deficiencies in the prior art, the purpose of the invention is to provide a single crystal manganese-based lithium battery positive electrode material and a preparation method thereof.

[0009] The specific technical solutions of the invention are as follows:

[0010] The application provides a single-crystal manganese-based lithium battery positive electrode material, and a composition general formula of the single-crystal manganese-based lithium battery positive electrode material is:

[0011] (1-x)Li 1+a Ni b Co k Mn 2-a-b-k-c-d-k Al c M d O 4-e / 2 F e ·xG·yLi f D g O h ;

[0012] Wherein, M is a doping element, G is a coating modifier, D is a metal or a metalloid, f, g and h satisfy Li f D g O h valence balance, 0 < x ≤ 10%, 2% < y ≤ 4.2%, 0.05 ≤ a ≤ 0.06, 0.01 < b ≤ 0.03, 0.01 < k ≤ 0.03, 0.04 ≤ c ≤ 0.07, 0.01 < d ≤ 0.06, 0.03 < e ≤ 0.07.

[0013] Specifically, the M is at least one of oxides, hydroxides, carbonates, acetates, nitrates and oxalates of Zr, La and La-based rare earth, Sb, Mg, Nb, Mo, Cr, Ta, Sr, K, Cs, V, Zn, In, Si, Rb, Y, B, Ga, Bi, Sn, Ge, W elements, or the M is oxides, hydroxides, carbonates, acetates, nitrates and oxalates of at least one of Zr, La and La-based rare earth, Sb, Mg, Nb, Mo, Cr, Ta, Sr, K, Cs, V, Zn, In, Si, Rb, Y, B, Ga, Bi, Sn, Ge, W elements.

[0014] Specifically, the G is Al2O3, Y2O3, AlPO4, LiFePO4, LiMn 1-n Fe n PO4, 0 < n < 1, LiNi m Mn 2-m O4, 0 < m ≤ 1.0, LiTi2(PO4)3, La2O3, FePO4, LiMnPO4, MnPO4, LiCoPO4, CoPO4, LiNiPO4, NiPO4, Mn 1- n Fe n PO4, 0 < n < 1, Li 1+p Al p Ti 2-p(PO4)3, 0≤p≤1, ZnO, Sb2O3, Bi2O3, Li3AlF6, LiAlF4, LiAlO2, Li4Ti5O 12 G is at least one of Al2O3, Sb2O3, Bi2O3, La2O3, CeO2, Y2O3, ZnO, Sc2O3; or G is an oxide after decomposition of at least one of pseudoboehmite, boehmite, Al(OH)3, Sb(OH)3, Bi(OH)3, La(OH)3, Ce(OH)4, Y(OH)3, Zn(OH)2, Sc(OH)3.

[0015] The oxide after decomposition of the pseudoboehmite, boehmite, Al(OH)3, Sb(OH)3, Bi(OH)3, La(OH)3, Ce(OH)4, Y(OH)3, Zn(OH)2, Sc(OH)3 is Al2O3, Sb2O3, Bi2O3, La2O3, CeO2, Y2O3, ZnO, Sc2O3.

[0016] The application further provides a preparation method of the single-crystal manganese-based lithium battery cathode material.

[0017] (1) mixing a part of a lithium source, a nickel source, a cobalt source, a manganese source, an aluminum source, an M source, and a fluorine source to obtain a mixture WL1;

[0018] (2) subjecting the mixture WL1 obtained in step (1) to a process of decomposition, oxidation, solid-phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing, and sieving to obtain a semi-product WL2 of a spinel structure and a large single-crystal morphology;

[0019] (3) weighing a certain amount of G, Li f D g O h , and grinding after adding water to obtain a mixed slurry WL3 at a nanoscale;

[0020] (4) uniformly mixing the mixed slurry WL3 obtained in step (3) with water, adding a remaining amount of the lithium source and the semi-product WL2 obtained in step (2), and continuing to uniformly mix for 2-6 hours, and drying to obtain a mixture WL4;

[0021] (5) subjecting the mixture WL4 obtained in step (4) to a process of decomposition, single-crystal recrystallization, crystal surface reconstruction, temperature reduction, crushing, sieving, and iron removal to obtain a single-crystal manganese-based lithium battery cathode material.

[0022] Specifically, in step (1),

[0023] The lithium source is at least one of Li2CO3, LiOH·H2O, Li2C2O4, LiOH, CH3COOLi, C4H9Li, C6H5Li, and LiF;

[0024] the fluorine source is at least one of MgF2, SbF3, CoF2, AlF3, AlF3.3H2O, LiF, GaF3, MnF2, YF3, SrF2, NiF2, MnF3, ZnF2, LaF3, NbF5, SnF2, BaF2, NH4F, LiAlF4, BiF3, ZrF4, CsF, Li3AlF6, SiF4;

[0025] the nickel source is at least one of carbonates, oxides, hydroxides, nitrates, fluorides, borides, oxalates, acetates containing Ni element; or the nickel source is at least one of Ni 1-q Mn q (OH)2, LiNiO2, LiNi 1-r-q C Or Mn q O2, LiNi 1-q C Oq O2, LiNi 1-r-q C Or Al q O2, LiNi 1-q Mn q O2, Ni 1-q C Oq (OH)2, Ni 1-r-q C Or Mn q (OH)2, Ni 1-r-q C Or Al q (OH)2; wherein 0

[0026] the cobalt source is at least one of carbonates, oxides, nitrates, hydroxides, fluorides, borides, oxalates, acetates containing Co element; or the cobalt source is at least one of LiCoO2, Ni 1-t C Ot (OH)2, Co 1-t Mn t (OH)2, LiNi 1-t-u C Ot Mn u O2, LiNi 1-z C Oz O2, 0 1-t-u C Ot Al u O2, LiCo 1- t Mn t O2, Ni 1-t-u C Ot Mnu (OH)2, Ni 1-t-u C Ot Al u (OH)2; wherein, 0 < t < 1.0, t + u < 1.0;

[0027] The manganese source is at least one of oxides, hydroxides, carbonates, nitrates, fluorides, borides, oxalates, acetates containing Mn element;

[0028] The aluminum source is at least one of hydroxides, nitrates, fluorides, oxides, acetates, oxalates, organic compounds containing Al element; or the aluminum source is at least one of pseudo-boehmite, boehmite, LiAlO2, Li3AlF6, LiAlF4.

[0029] Preferably, in the step (2), the decomposition, oxidation, solid phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing and sieving process is specifically as follows: the mixed material WL1 is decomposed, oxidized, solid phase melted, crystal nucleated and grown at a temperature of 630-710 DEG C for 9-17 hours under a protective air atmosphere, then the temperature is continuously increased to 930-990 DEG C, the crystal is recrystallized for 12-18 hours, the temperature is reduced to 600-1690 DEG C, the crystal is repaired by calcination for 5-18 hours, then the temperature is reduced to room temperature, and the crushing and sieving process is performed.

[0030] The primary grain size of the semi-finished product WL2 is 1.0-5.0 microns.

[0031] Preferably, in the step (3), the particle size of the mixed slurry WL3 is 200-800 nm.

[0032] In the step (5), the primary grain size of the single-crystal manganese-based lithium battery cathode material is 1.5-6.0 microns.

[0033] Preferably, in the step (5), the decomposition, single-crystal recrystallization, crystal surface reconstruction, temperature reduction, crushing, sieving and demagnetization process is specifically as follows: the mixed material WL4 is decomposed, single-crystal recrystallized and crystal surface reconstructed at a temperature of 580-670 DEG C for 12-17 hours under an air atmosphere in a synthesis sintering furnace, then the temperature is reduced to room temperature, and the crushing, sieving and demagnetization process is performed.

[0034] The present application controls the material reaction temperature and reaction time to regulate the size of the primary particles of the material crystal and the crystal morphology, reduces the specific surface area of the material, reduces the manganese dissolution crystal surface, and enhances the stability of the two phases during the Li+ extraction and insertion in the charge and discharge cycle process. +

[0035] ​Preferably, in step (4), the molar ratio of the residual lithium to the semi-finished product WL2 is 0.24-0.45:1.

[0036] The application further provides a lithium battery comprising the single-crystal manganese-based lithium battery cathode material.

[0037] The application has the following beneficial effects:

[0038] The application regulates the oxidation state of Mn by the interaction between the composite metal ion synergistic doping and the anion-cation synergistic doping, thereby inhibiting the structure phase transition caused by the Jahn-Teller distortion effect in the charging and discharging process, improving the stability of the material main skeleton and reducing the disproportionation reaction at the end of discharging, and thus improving the defect of rapid capacity attenuation in the charging and discharging cycle process of the material and enhancing the cycle performance of the material.

[0039] The application adds the lithium-rich compound Li f D g O h The excess lithium can effectively supplement the large amount of lithium from the positive electrode consumed when the solid electrolyte interface (SEI) film is formed on the negative electrode surface, is beneficial to improving the coulombic efficiency (ICE) of the material in the first cycle, and can also reduce the phase transition caused by the structure instability after lithium is removed, thereby prolonging the cycle life.

[0040] The material has the advantages of high specific capacity, large battery pole piece compaction density, long room temperature cycle life, good rate discharge, good high-temperature cycle and storage performance, and the like, and can be used for manufacturing high-end lithium manganate batteries, and can also be mixed with nickel-cobalt-manganese lithium manganate, nickel-cobalt-aluminum lithium manganate, cobalt lithium manganate, manganese-iron-phosphate lithium, and other lithium battery cathode materials to manufacture lithium ion batteries, thereby meeting the use requirements of new energy vehicles, electric bicycles, electric ships, household energy storage, portable energy storage, electric tools, and communication devices.

[0041] The preparation method is simple, easy to industrialize, and can form multiple products to meet different market demands. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A particle morphology diagram of the single-crystal manganese-based lithium battery cathode material prepared in Example 8.

[0043] Figure 2 A particle size distribution diagram of the single-crystal manganese-based lithium battery cathode material prepared in Example 8.

[0044] Figure 3 A simulated battery room temperature 0.2C current charging and discharging curve diagram of the single-crystal manganese-based lithium battery cathode material prepared in Example 8.

[0045] Figure 4The single-crystal manganese-based lithium battery cathode material full cell normal temperature environment, 1C current charge-discharge cycle performance trend chart prepared for example 8.

[0046] Figure 5 The single-crystal manganese-based lithium battery cathode material full cell 45 DEG C environment, 1C current charge-discharge cycle performance trend chart prepared for example 8. DETAILED DESCRIPTION

[0047] The application provides a preparation method of a single-crystal manganese-based lithium battery cathode material, comprising the following steps:

[0048] (1) a part of a lithium source, a nickel source, a cobalt source, a manganese source, an aluminum source, an M source and a fluorine source are uniformly mixed to obtain a mixed material WL1;

[0049] (2) the mixed material WL1 obtained in step (1) is subjected to a process of decomposition, oxidation, solid-phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing and sieving to obtain a semi-product WL2 with a spinel structure and a large single-crystal morphology;

[0050] (3) a certain amount of G, Li f D g O h , and water is added and ground to obtain a nano-sized mixed slurry WL3;

[0051] (4) the mixed slurry WL3 obtained in step (3) is uniformly mixed with water, and the remaining lithium source and the semi-product WL2 obtained in step (2) are added and uniformly mixed for 2-6 hours, and then dried to obtain a mixed material WL4;

[0052] (5) the mixed material WL4 obtained in step (4) is subjected to a process of decomposition, single-crystal recrystallization, crystal surface reconstruction, temperature reduction, crushing, sieving and iron removal to obtain a single-crystal manganese-based lithium battery cathode material.

[0053] In the preparation of the intermediate crystal grains, that is, in step (2), the process of decomposition, oxidation, solid-phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing and sieving is specifically as follows: the mixed material WL1 is decomposed, oxidized, solid-phase melted, crystal nucleated and grown at a temperature of 300-750 DEG C for 3-20 hours under the condition of a protective air atmosphere, then the temperature is continuously increased to 850-1150 DEG C, the crystal is recrystallized and synthesized for 5-30 hours, the temperature is reduced to 750-450 DEG C, the crystal is subjected to a repairing roasting for 3-10 hours, and then the temperature is reduced to room temperature, and the process of crushing and sieving is carried out; the size of the primary crystal grains of the semi-product WL2 is in the range of 1.0-5.0 μm.

[0054] The particle size of the mixed slurry WL3 is 200-800 nm;

[0055] The prepared single-crystal manganese-based lithium battery cathode material has a primary grain size ranging from 1.5 to 6.0 μm.

[0056] The decomposition, single-crystal recrystallization, crystal surface reconstruction, temperature reduction, crushing, sieving and demagnetization processes are as follows: the mixed material WL4 is subjected to decomposition, single-crystal recrystallization, crystal surface reconstruction at a temperature of 300-750°C for 5-20 hours in a synthesis sintering furnace under air atmosphere, and then is reduced to room temperature, crushed, sieved and demagnetized.

[0057] In step (4), the molar ratio of the remaining amount to the semi-finished product WL2 is 0.24-0.45:1.

[0058] The prepared single-crystal manganese-based lithium battery cathode material has a composition general formula of:

[0059] (1-x)Li 1+a Ni b Co k Mn 2-a-b-k-c-d-k Al c M d O 4-e / 2 F e ·xG·yLi f D g O h ;

[0060] wherein M is a doping element, G is a coating modifier, D is a metal or a metalloid, and f, g and h satisfy Li f D g O h valence balance, 0

[0061] The M can be at least one of oxides, hydroxides, carbonates, acetates, nitrates and oxalates of Zr, La and La-based rare earths, Sb, Mg, Nb, Mo, Cr, Ta, Sr, K, Cs, V, Zn, In, Si, Rb, Y, B, Ga, Bi, Sn, Ge and W, or the M is at least one of oxides, hydroxides, carbonates, acetates, nitrates and oxalates of Zr, La and La-based rare earths, Sb, Mg, Nb, Mo, Cr, Ta, Sr, K, Cs, V, Zn, In, Si, Rb, Y, B, Ga, Bi, Sn, Ge and W.

[0062] Similarly, the coating modifier G can be Al2O3, Y2O3, AlPO4, LiFePO4, LiMn 1-n Fen PO4, 0 < n < 1, LiNi m Mn 2-m PO4, 0 < m < 1.0, LiTi2(PO4)3, La2O3, FePO4, LiMnPO4, MnPO4, LiCoPO4, CoPO4, LiNiPO4, NiPO4, Mn 1-n Fe n PO4, 0 < n < 1, Li 1+p Al p Ti 2-p (PO4)3, 0 < p < 1, ZnO, Sb2O3, Bi2O3, Li3AlF6, LiAlF4, LiAlO2, Li4Ti5O 12 , Co3O4, Sc2O3; or G is an oxide decomposed from at least one of pseudoboehmite, boehmite, Al(OH)3, Sb(OH)3, Bi(OH)3, La(OH)3, Ce(OH)4, Y(OH)3, Zn(OH)2, Sc(OH)3.

[0063] In step (1) of the preparation method, the lithium source can be at least one of Li2CO3, LiOH H2O, Li2C2O4, LiOH, CH3COOLi, C4H9Li, C6H5Li, LiF;

[0064] The fluorine source can be at least one of MgF2, SbF3, CoF2, AlF3, AlF3 3H2O, LiF, GaF3, MnF2, YF3, SrF2, NiF2, MnF3, ZnF2, LaF3, NbF5, SnF2, BaF2, NH4F, LiAlF4, BiF3, ZrF4, CsF, Li3AlF6, SiF4;

[0065] The nickel source is at least one of carbonates, oxides, hydroxides, nitrates, fluorides, borides, oxalates, acetates containing Ni element; or the nickel source is at least one of Ni 1-q Mn q (OH)2, LiNiO2, LiNi 1-r-q C Or Mn q O2, LiNi 1-q C Oq O2, LiNi 1-r-q C Or Al q O2, LiNi 1-q Mn q O2, Ni 1-q COq (OH)2, Ni 1-r-q C Or Mn q (OH)2, Ni 1-r-q C Or Al q (OH)2; wherein, 0 < q < 1.0, r + q < 1.0;

[0066] The cobalt source is at least one of carbonates, oxides, nitrates, hydroxides, fluorides, borides, oxalates, acetates containing Co element; or the cobalt source is at least one of LiCoO2, Ni 1-t C Ot (OH)2, Co 1-t Mn t (OH)2, LiNi 1-t-u C Ot Mn u O2, LiNi 1-z C Oz O2, 0 ≤ z ≤ 1.0, LiNi 1-t-u C Ot Al u O2, LiCo 1- t Mn t O2, Ni 1-t-u C Ot Mn u (OH)2, Ni 1-t-u C Ot Al u (OH)2; wherein, 0 < t < 1.0, t + u < 1.0;

[0067] The manganese source is at least one of oxides, hydroxides, carbonates, nitrates, fluorides, borides, oxalates, acetates containing Mn element;

[0068] The aluminum source is at least one of hydroxides, nitrates, fluorides, oxides, acetates, oxalates, organic compounds containing Al element; or the aluminum source is at least one of pseudoboehmite, boehmite, LiAlO2, Li3AlF6, LiAlF4.

[0069] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0070] The specific implementation of the present application is described in detail below in combination with specific embodiments.

[0071] Example 1

[0072] The embodiment provides a single-crystal manganese-based lithium battery cathode material, a preparation method thereof, and comprises the following steps:

[0073] S1. Li2CO3, NiCO3, CoCO3, MnO2, Al(OH)3, ZrO2, and MgF2 required are weighed according to a molar ratio of Li:Ni:Mn:Al:Zr:F of 0.6:0.01:0.02:1.79:0.08:0.01:0.04, and then are uniformly mixed in a high-efficiency high-speed mixer for 40 minutes to obtain a mixed material WL1;

[0074] S2. The mixed material WL1 is loaded into a crucible, and is decomposed, oxidized, solid-phase melted, crystal nucleated, and crystal grown in a synthesis sintering furnace under an air atmosphere at a temperature of 680 DEG C for 10 hours, is recrystallized at a temperature of 985 DEG C for 15 hours, is cooled to 620 DEG C, is subjected to a restorative roasting on the crystal for 6 hours, is cooled to room temperature, is broken, and is sieved to obtain a half-finished product of a spinel structure, a single-crystal morphology, Li + / vacancy Ni 0.01 Co 0.02 Mn 1.83 Al 0.05 Zr 0.01 Mg 0.02 O 3.98 F 0.04 , a primary grain size range of 1.0-5.0 μm, and Li , wherein the Li + vacancy means; the half-finished product prepared in the process is abbreviated as WL2;

[0075] S3. Al2O3 of 1.5% of the total mass of the finished product and Li2NiO2 of 2.5% of the total mass of the finished product and pure water of 2 times the mass of the two are weighed, are ground and broken by a sand mill to obtain a mixed slurry of nano-sized Al2O3 and Li2NiO2, a particle size PSD-D50 of 200-800 nm, and the half-finished product prepared in the process is abbreviated as WL3;

[0076] S4. The mixed slurry of WL3 is transferred into a mixing and drying all-in-one machine device, pure water of the same mass as the total mass of the finished product is further added, and is uniformly mixed for 1 hour; the remaining lithium and the half-finished product WL2 are weighed, a molar ratio of Li to the half-finished product WL2 is 0.45:1, and the mass of the two satisfies that the product of the reaction and synthesis of the two accounts for 96% of the total mass of the finished product, and the two are put into the mixing and drying all-in-one machine device, and are uniformly mixed for 5 hours, and are dried to obtain a mixed material WL4;

[0077] S5. Put the WL4 material into a crucible, and decompose, recrystallize the single crystal WL2, and restructure the surface of the crystal in a synthesis sintering furnace under an air atmosphere at a temperature of 650°C for 16 hours, and then reduce to room temperature, crush, sieve, and remove the magnetism to obtain a single-crystal manganese-based lithium battery cathode material 96% Li 1.05 Ni 0.01 Co 0.02 Mn 1.83 Al 0.05 Zr 0.01 Mg 0.02 O 3.98 F 0.04 1.5% Al2O3 2.5% Li2NiO2, and the primary grain size is 1.5-6.0 μm.

[0078] Example 2

[0079] The example provides a single-crystal manganese-based lithium battery cathode material, and a preparation method thereof, including the following steps:

[0080] S1. Weigh the required Li2CO3, NiO, Co3O4, Mn3O4, Al(OH)3, La2O3, and SbF3 according to a Li:Ni:Mn:Al:La:F molar ratio of 0.7:0.01:0.01:1.83:0.06:0.02:0.03, and then put them into a high-efficiency high-speed mixer to uniformly mix for 45 minutes to obtain a mixed material WL1;

[0081] S2. Put the mixed material WL1 into a crucible, and decompose, oxidize, solid-phase melt, and crystallize in a synthesis sintering furnace under an air atmosphere at a temperature of 670°C for 9 hours, and then raise the temperature to 970°C, recrystallize the crystal for 17 hours, reduce the temperature to 620°C, and perform a restorative roasting on the crystal for 8 hours, and then reduce to room temperature, crush, sieve, and obtain a spinel-structured single-crystal morphology Li + / vacancy semi-finished product Ni 0.01 Co 0.01 Mn 1.81 Al 0.06 La 0.02 Sb 0.01 O 3.985 F 0.03 , and the primary grain size ranges from 1.0 to 5.0 μm; the semi-finished product prepared in this process is referred to as WL2;

[0082] S3. Take 0.7% of Y2O3 and 2.0% of lithium-rich oxide Li5FeO4 of the total mass of the finished product and 2 times the mass of pure water, grind and crush through a sand mill to obtain a mixed slurry of Y2O3 and Li5FeO4 at the nanoscale, with a particle size PSD-D50 of 200-400 nm. The semi-finished product prepared in this process is referred to as WL3.

[0083] S4. Transfer all of the WL3 slurry to a mixing and drying all-in-one machine, and then add pure water with the same mass as the total mass of the finished product, and uniformly mix for 1 hour. According to the required mass ratio, take the remaining amount of lithium and semi-finished product WL2, with a Li to semi-finished product WL2 molar ratio of 0.38:1, and the mass of the two satisfies that the product of the reaction synthesis accounts for 97.3% of the total mass of the finished product. Put them into the mixing and drying all-in-one machine, and continue to uniformly mix for 5 hours to obtain the mixed material WL4.

[0084] S5. Put the WL4 material into a crucible, and perform decomposition, single crystal recrystallization, and crystal surface reconstruction at a temperature of 670°C for 17 hours in an air atmosphere synthesis sintering furnace, and then reduce to room temperature. Crush, sieve, and remove the magnetism to obtain a single-crystal manganese-based lithium battery positive electrode material 97.3% Li 1.08 Ni 0.01 Co 0.01 Mn 1.81 Al 0.06 La 0.02 Sb 0.01 O 3.985 F 0.03 ·0.7% Y2O3·2.0% Li5FeO4, with a primary grain size of 1.5-6.0 μm.

[0085] Example 3

[0086] The example provides a single-crystal manganese-based lithium battery positive electrode material, and a preparation method thereof, including the following steps:

[0087] S1. Take LiOH·H2O, Ni(OH)2, Mn2O3, Al(OH)3, Sb2O3, and CoF2 according to a Li:Ni:Mn:Al:Sb:F molar ratio of 0.75:0.02:1.84:0.05:0.01:0.04, and then put them into a high-efficiency high-speed mixer to uniformly mix for 50 minutes to obtain a mixed material WL1;

[0088] S2. Put the mixed material WL1 into a crucible, and decompose, oxidize, solid-phase melt, crystal nucleate, and grow in a synthesis sintering furnace under an air atmosphere at a temperature of 690°C for 9 hours, then raise the temperature to 990°C, recrystallize the crystal for 12 hours, lower the temperature to 690°C, perform restorative baking on the crystal for 5 hours, lower to room temperature, break and sieve to obtain spinel-structured large single-crystal-shaped Li + / vacancy semi-finished product Ni 0.02 Co 0.02 Mn 1.84 Al 0.05 Sb 0.01 O 3.98 F 0.04 , and the primary grain size thereof ranges from 1.0 to 5.0 μm; the semi-finished product prepared in this process is referred to as WL2;

[0089] S3. Take 0.5% of AlPO4 and 2.0% of lithium-rich oxide Li5FeO4 by total mass of the finished product, and 2 times the mass of pure water, grind and break through a sand mill to obtain a mixed slurry of nano-sized AlPO4 and Li5FeO4, and the particle size PSD-D50 thereof ranges from 200 to 400 nm; the semi-finished product prepared in this process is referred to as WL3;

[0090] S4. Transfer all of the WL3 slurry into a mixing and drying all-in-one machine device, and then add pure water with a mass equal to the total mass of the finished product, and uniformly mix for 1 hour; according to the required mass ratio, take the rest of lithium and semi-finished product WL2, and the molar ratio of Li to semi-finished product WL2 is 0.31:1, and the mass of the two satisfies that the product of the reaction and synthesis accounts for 97.5% of the total mass of the finished product, and put into the mixing and drying all-in-one machine device, and continue to uniformly mix for 5 hours, and dry to obtain mixed material WL4;

[0091] S5. Put the WL4 material into a crucible, and decompose, recrystallize the single-crystal WL2, and reconstruct the crystal surface in a synthesis sintering furnace under an air atmosphere at a temperature of 650°C for 15 hours, and then lower to room temperature, break, sieve, and remove the magnetism to obtain single-crystal manganese-based lithium battery positive electrode material 97.5% Li 1.06 Ni 0.02 Co 0.02 Mn 1.84 Al 0.05 Sb 0.01 O 3.98 F 0.04 ·0.5% AlPO4·2.0% Li5FeO4, and the primary grain size thereof ranges from 1.5 to 6.0 μm.

[0092] Example 4

[0093] The embodiment provides a single-crystal manganese-based lithium battery positive electrode material and a preparation method thereof, and comprises the following steps:

[0094] S1. LiOH·H2O, Ni 0.5 C O0.5 (OH)2, Mn(OH)2, AlOOH·nH2O, MgO, AlF3 are weighed according to the molar ratio of Li:Ni:C O ∶Mn∶Al∶Mg∶F is 0.81∶0.02∶0.02∶1.67∶0.05∶0.02∶0.06, and then the mixture is uniformly mixed in a high-efficiency high-speed mixer for 45 minutes to obtain a mixed material WL1;

[0095] S2. The mixed material WL1 is loaded into a crucible, and is decomposed, oxidized, solid-phase melted, crystal nucleated and grown in a synthesis sintering furnace under an air atmosphere at a temperature of 700 DEG C for 10 hours, is heated to 930 DEG C, and is recrystallized for 18 hours, is cooled to 650 DEG C, and is subjected to restorative roasting on the crystal for 6 hours, is cooled to room temperature, is broken and sieved to obtain a spinel-structured large single-crystal morphology Li + / vacancy semi-finished product Ni 0.02 Co 0.02 Mn 1.82 Al 0.07 Mg 0.02 O 3.97 F 0.06 , and the primary grain size ranges from 1.0 to 5.0 microns; the semi-finished product prepared in the process is abbreviated as WL2;

[0096] S3. LiFePO4 with a total mass of 6.0% of the finished product and lithium-rich oxide Li2NiO2 with a mass of 2.0% of the finished product and pure water with a mass of twice the mass of the two are weighed, are ground and broken by a sand mill, and a mixed slurry of nanoscale LiFePO4 and Li2NiO2 is obtained, the particle size PSD-D50 of the mixed slurry is 200-400 nm, and the semi-finished product prepared in the process is abbreviated as WL3;

[0097] S4. The WL3 slurry is transferred into a mixing and drying all-in-one machine device, pure water with a mass equal to the total mass of the finished product is further added, and the mixture is uniformly mixed for 1 hour; according to the required mass ratio, the remaining lithium and the semi-finished product WL2 are weighed, the molar ratio of lithium to the semi-finished product WL2 is 0.24:1, and the mass of the two satisfies that the product synthesized by the reaction of the two accounts for 92% of the total mass of the finished product, and the two are uniformly mixed in the mixing and drying all-in-one machine device for 4 hours, and are dried to obtain a mixed material WL4;

[0098] S5. Put the WL4 material into a crucible, and decompose, recrystallize the single crystal WL2, and reconstruct the crystal surface in a synthetic sintering furnace under an air atmosphere at a temperature of 580°C for 20 hours, and then reduce to room temperature, crush, sieve, and remove the magnetism to obtain the single-crystal manganese-based lithium battery cathode material 92% Li 1.05 Ni 0.02 Co 0.02 Mn 1.82 Al 0.07 Mg 0.02 O 3.97 F 0.06 ·6% LiFePO4·2.0% Li2NiO2, with a primary grain size of 1.5-6.0 μm.

[0099] Example 5

[0100] The example provides a single-crystal manganese-based lithium battery cathode material, a preparation method thereof, including the following steps:

[0101] S1. Weigh the required LiOH·H2O, Ni 1 / 3 C O1 / 3 Mn 1 / 3 (OH)2, Mn3O4, MnCO3, γ-AlOOH, Nb2O5, AlF3·H2O according to the molar ratio of Li:Ni:C O ∶Mn∶Mn∶Mn∶Al∶Nb∶F is 0.75∶0.02∶0.02∶0.02∶1.74∶0.1∶0.03∶0.01∶0.06, and then put into a high-efficiency high-speed mixer for uniform mixing for 60 minutes to obtain the mixed material WL1;

[0102] S2. Put the mixed material WL1 into a crucible, decompose, oxidize, solid-phase melt, crystal nucleation, and crystal growth in a synthetic sintering furnace under an air atmosphere at a temperature of 630°C for 10 hours, increase the temperature to 955°C, recrystallize the crystal for 17 hours, reduce the temperature to 600°C, perform restorative roasting on the crystal for 7 hours, reduce to room temperature, crush, sieve, and obtain the spinel-structured large single-crystal morphology, Li + / vacancy semi-finished product Ni 0.02 Co 0.02 Mn 1.76 Al 0.05 Nb 0.01 O 3.97 F 0.06 , with a primary grain size range of 1.0-5.0 μm; the semi-finished product prepared in this process is referred to as WL2;

[0103] S3. Weigh 10.0% of the total mass of the finished product LiMn 0.5 Fe 0.5LiMn 0.5 Fe 0.5 PO4 and Li2NiO2 with a particle size PSD-D50 of 200-400 nm, and the semi-finished product prepared in this process is referred to as WL3;

[0104] S4. All of the WL3 slurry is transferred into a mixing and drying all-in-one machine, and pure water with a mass equal to the total mass of the finished product is added and uniformly mixed for 1 hour; according to the required mass ratio, the remaining amount of lithium and the semi-finished product WL2 are weighed, the molar ratio of Li to the semi-finished product WL2 is 0.31:1, and the mass of the two satisfies that the product of the reaction and synthesis of the two accounts for 87% of the total mass of the finished product, and the two are placed into the mixing and drying all-in-one machine and uniformly mixed for 4 hours, and then dried to obtain the mixed material WL4;

[0105] S5. The WL4 material is loaded into a crucible and subjected to decomposition, single-crystal crystal WL2 recrystallization, and crystal surface reconstruction in a synthesis sintering furnace under an air atmosphere at a temperature of 610 DEG C for 12 hours, and then cooled to room temperature, crushed, and sieved to remove iron to obtain a single-crystal manganese-based lithium battery positive electrode material 87% Li 1.06 Ni 0.02 Co 0.02 Mn 1.76 Al 0.05 Nb 0.01 O 3.97 F 0.06 ·10.0% LiMn 0.5 Fe 0.5 PO4·3.0% Li2NiO2, and the primary grain size is 1.5-6.0 μm.

[0106] Example 6

[0107] The example provides a single-crystal manganese-based lithium battery positive electrode material, and a preparation method thereof, including the following steps:

[0108] S1. Li2C2O4, NiCO3, C O CO3, Mn3O4, C 54 H 105 AlO6 (aluminum stearate), MoO3, La2O3, LiF are weighed according to a molar ratio of Li:Ni:C O :Mn:Al:Mo:La:F of 0.70:0.02:0.03:1.82:0.04:0.01:0.02:0.04, and then uniformly mixed in a high-efficiency high-speed mixer for 55 minutes to obtain a mixed material WL1;

[0109] S2. Put the mixed material WL1 into a crucible, and decompose, oxidize, solid-phase melt, crystal nucleate, and crystal grow in a synthesis sintering furnace under an air atmosphere at a temperature of 710°C for 17 hours, increase the temperature to 970°C, recrystallize the crystal for 18 hours, decrease the temperature to 610°C, perform restorative baking on the crystal for 6 hours, decrease to room temperature, break and sieve to obtain spinel-structured large single-crystal-shaped Li + / vacancy semi-finished product Ni 0.02 Co 0.03 Mn 1.82 Al 0.04 Mo 0.01 La 0.02 O 3.98 F 0.04 , with a primary grain size ranging from 1.0 to 5.0 μm; the semi-finished product prepared in this process is referred to as WL2;

[0110] S3. Take LiNi 0.2 Mn 1.8 O4 and 3.5% of lithium-rich oxide Li2NiO2, and 2 times the mass of pure water, grind and break through a sand mill to obtain a mixed slurry of LiNi 0.5 Mn 1.5 O4 and Li2NiO2, with a particle size PSD-D50 of 200-400 nm; the semi-finished product prepared in this process is referred to as WL3;

[0111] S4. Transfer all of the WL3 slurry to a mixing and drying all-in-one machine device, and then add pure water with a mass equal to the total mass of the finished product, and uniformly mix for 1 hour; according to the required mass ratio, take the remaining amount of lithium and semi-finished product WL2, with a Li to semi-finished product WL2 molar ratio of 0.32:1, and a mass that satisfies that the product of the reaction and synthesis of the two accounts for 95.5% of the total mass of the finished product, and place into the mixing and drying all-in-one machine device, and continue to uniformly mix for 5 hours, and dry to obtain mixed material WL4;

[0112] S5. Put the WL4 material into a crucible, and decompose, recrystallize the single-crystal WL2, and reconstruct the crystal surface in a synthesis sintering furnace under an air atmosphere at a temperature of 620°C for 17 hours, decrease to room temperature, break and sieve, and remove the magnet to obtain single-crystal manganese-based lithium battery positive electrode material 95.5% Li 1.06 Ni 0.02 Co 0.03 Mn 1.82 Al 0.04 Mo 0.01 La 0.02 O 3.98 F 0.04 ·1.0% LiNi 0.2 Mn 1.8O4·3.5%Li2NiO2, with a primary grain size of 1.5–6.0 μm.

[0113] Example 7

[0114] This embodiment provides a single-crystal manganese-based lithium battery cathode material, the preparation method of which includes the following steps:

[0115] S1. Mix the required Li2CO3, Ni(OH)2, LiCoO2, Mn3O4, MnO2, Al(NO3)3, Cr2O3, La2O3, and GaF3 according to the ratio Li:Ni:C O The molar ratio of Mn:Mn:Al:Cr:La:F is 0.77:0.01:0.01:1.04:0.8:0.04:0.02:0.02:0.06. The mixture is weighed and then put into a high-efficiency high-speed mixer and mixed evenly for 55 minutes to obtain mixture WL1.

[0116] S2. The mixture WL1 was placed in a crucible and, in a synthesis sintering furnace under air atmosphere, decomposed, oxidized, melted in the solid phase, nucleated and grew crystals at 680℃ for 15 hours. The temperature was then raised to 975℃ for recrystallization and synthesis for 17 hours. The temperature was then lowered to 620℃ for restorative calcination of the crystals for 6 hours. After cooling to room temperature, the crystals were crushed and sieved to obtain large single crystals of Li with a spinel structure. + / Empty semi-finished products Ni 0.01 Co 0.01 Mn 1.84 Al 0.04 Cr 0.02 La 0.02 Ga 0.02 O 3.97 F 0.06 Its primary grain size ranges from 1.0 to 5.0 μm; the semi-finished product prepared by this process is simply referred to as WL2;

[0117] S3. Weigh 0.7% of the total mass of LiTi2(PO4)3 and 2.5% of the lithium-rich oxide Li6CoO4 and twice the mass of pure water. Grind and crush them in a sand mill to obtain a nano-sized mixed slurry of LiTi2(PO4)3 and Li6CoO4 with a particle size PSD-D50 of 200-400 nm. The semi-finished product prepared in this process is referred to as WL3.

[0118] S4. All of the WL3 slurry is transferred into a mixing-drying integrated machine device, and pure water with the same mass as the total mass of the finished product is added and uniformly mixed for 1 hour; according to the required mass ratio, the remaining amount of lithium and the semi-finished product WL2 is weighed, the molar ratio of Li to the semi-finished product WL2 is 0.27:1, and the mass of the two satisfies that the product of the reaction of the two accounts for 95.8% of the total mass of the finished product, and the two are put into the mixing-drying integrated machine device and uniformly mixed for 5 hours, and then dried to obtain the mixed material WL4;

[0119] S5. The WL4 material is loaded into a crucible, and is subjected to decomposition, single crystal recrystallization and crystal surface reconstruction at a temperature of 600 DEG C for 15 hours in an air atmosphere synthesis sintering furnace, is cooled to room temperature, is broken, sieved and demagnetized to obtain a single-crystal manganese-based lithium battery positive electrode material 95.8% Li 1.04 Ni 0.01 Co 0.01 Mn 1.84 Al 0.04 Cr 0.02 La 0.02 Ga 0.02 O 3.97 F 0.06 ·0.7% LiTi2(PO4)3·3.5% Li6CoO4, the primary grain size of which is 1.5-6.0 μm.

[0120] Example 8

[0121] The example provides a single-crystal manganese-based lithium battery positive electrode material, a preparation method thereof, and comprises the following steps:

[0122] S1. Li2CO3, LiNiO2, Ni 0.5 C O0.5 (OH)2, MnO2, Al(OH)3, AlF3, Nb(OH)5, La2O3, MnF2 required are weighed according to a molar ratio of Li:Ni:Co:Mn:Al:Al:Nb:La:F of 0.7:0.02:0.01:1.83:0.04:0.01:0.01:0.02:0.04, and then are uniformly mixed in a high-efficiency high-speed mixer for 55 minutes to obtain a mixed material WL1;

[0123] S2. The mixed material WL1 is loaded into a crucible, is subjected to decomposition, oxidation, solid-phase melting, crystal nucleation and crystal growth at a temperature of 670 DEG C for 12 hours in an air atmosphere synthesis sintering furnace, is heated to 985 DEG C, is subjected to crystal recrystallization synthesis for 16 hours, is cooled to 680 DEG C, is subjected to restorative calcination of the crystal for 6 hours, is cooled to room temperature, is broken, sieved and demagnetized to obtain a spinel-structured large single-crystal morphology, Li + / vacancy semi-finished product Ni 0.03 Co0.01 Mn 1.85 Al 0.05 Nb 0.01 La 0.02 O 3.965 F 0.07 Its primary grain size ranges from 1.0 to 5.0 μm; the semi-finished product prepared by this process is simply referred to as WL2;

[0124] S3. Weigh 0.5% of the total mass of the finished product, 1.0% of the total mass of La2O3, 8% of the total mass of Al2O3, 8% of the total mass of LiFePO4, and 2.0% of the total mass of the lithium-rich oxide Li2NiO2, and twice the mass of the four components of pure water. Grind and crush them together in a sand mill to obtain a nano-sized mixed slurry with a particle size PSD-D50 of 200-400 nm. The semi-finished product prepared in this process is referred to as WL3.

[0125] S4. Transfer all of the WL3 slurry to the integrated mixing and drying machine, then add pure water of equal mass to the total mass of the finished product, and mix evenly for 1 hour; according to the required mass ratio, weigh the remaining lithium and semi-finished product WL2, with the molar ratio of Li to semi-finished product WL2 being 0.34:1, and the mass of both satisfying that the product synthesized by the reaction accounts for 88.5% of the total mass of the finished product, put them into the integrated mixing and drying machine and mix evenly for 5 hours, then dry to obtain the mixture WL4;

[0126] S5. The WL4 material was placed in a crucible and subjected to decomposition, recrystallization of single-crystal WL2, and crystal surface reconstruction at 620°C in a synthesis sintering furnace under air atmosphere for 15 hours. After cooling to room temperature, the material was crushed and sieved to remove iron, yielding 88.5% Li single-crystal manganese-based lithium battery cathode material. 1.06 Ni 0.03 Co 0.01 Mn 1.85 Al 0.05 Nb 0.01 La 0.02 O 3.965 F 0.07 ·9.5% (La2O3·Al2O3·LiFePO4)·2.0% Li2NiO2, with a primary grain size of 1.5~6.0μm.

[0127] The particle morphology of the single-crystal manganese-based lithium battery cathode material prepared in this embodiment is shown in the figure below. Figure 1 As shown in the figure, the single crystals are clear and free of agglomeration. The particle size distribution of the single-crystal manganese-based lithium battery cathode material prepared in this embodiment is shown in the figure. Figure 2 As shown, the particle size D10 = 2.94 μm, the particle size D50 = 6.61 μm, and the particle size D90 = 14.41 μm.

[0128] Example 9

[0129] The difference from Example 1 is that:

[0130] The decomposition, oxidation, solid phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing and sieving in step S2 are as follows: the mixed material is loaded into a crucible, and is decomposed, oxidized, solid phase melted, crystal nucleated and grown at 710℃ for 8 hours in a synthesis sintering furnace under air atmosphere, is recrystallized at 1020℃ for 12 hours, is reduced to 650℃, is subjected to restorative baking for 8 hours, is reduced to room temperature, is crushed and sieved.

[0131] The decomposition, single crystal recrystallization and crystal surface reconstruction in step S5 are as follows: the material is loaded into a crucible, is decomposed, single crystal recrystallized and crystal surface reconstructed at 620℃ for 20 hours in a synthesis sintering furnace under air atmosphere, is reduced to room temperature, is crushed, sieved and demagnetized.

[0132] Example 10

[0133] The difference from Example 1 is that:

[0134] The decomposition, oxidation, solid phase melting, crystal nucleation, crystal growth, crystal recrystallization, temperature reduction, crushing and sieving in step S2 are as follows: the mixed material is loaded into a crucible, and is decomposed, oxidized, solid phase melted, crystal nucleated and grown at 710℃ for 8 hours in a synthesis sintering furnace under air atmosphere, is recrystallized at 1020℃ for 12 hours, is reduced to 650℃, is subjected to restorative baking for 8 hours, is reduced to room temperature, is crushed and sieved.

[0135] The decomposition, single crystal recrystallization and crystal surface reconstruction in step S5 are as follows: the material is loaded into a crucible, is decomposed, single crystal recrystallized and crystal surface reconstructed at 620℃ for 20 hours in a synthesis sintering furnace under air atmosphere, is reduced to room temperature, is crushed, sieved and demagnetized.

[0136] Test Example 1

[0137] The performance of the single crystal manganese-based lithium battery cathode material prepared in Examples 1-8 is shown in Table 1. The performance of the single crystal manganese-based lithium battery cathode material prepared in Example 8 is shown in Table 1, and the specific data is shown in Table 1. The test methods and instrument devices of the physical properties and electrochemical properties are shown in Table 2. Figures 3-5

[0138] Table 1 Performance of single crystal manganese-based lithium battery cathode material prepared in Examples 1-8 of the application

[0139] ​

[0140] Note: charge-discharge voltage limit: 4.2-3.0V.

[0141] The performance comparison data of the single-crystal manganese-based lithium battery cathode material prepared by the embodiments 1-8 of the present application and the single-crystal manganese-based lithium battery cathode material in the prior art are shown in Table 2.

[0142] Table 2

[0143]

[0144]

[0145] Note: charge-discharge voltage limit: 4.2-3.0V.

[0146] From Tables 1-2 and Figures 3-5 It can be seen that, compared with the single-crystal manganese-based cathode material prepared by the prior art process, the single-crystal manganese-based lithium battery cathode material prepared by the present application has good stability, high safety, high charge-discharge efficiency, long room-temperature cycle life, good high-temperature storage (45℃, storage for 28 days, capacity reduction rate is about 1 / 3 of the cathode material containing the prior art-prepared cathode material) and cycle performance (more than 2 times).

Claims

1. A single-crystal manganese-based lithium battery cathode material, characterized in that, The general formula for the cathode material of the single-crystal manganese-based lithium battery is: (1-xy) Li 1+a Ni b Co k Mr 2-a-b-k-c-d Al c M d O 4-e / 2 F e ·xG·yLi f D g O h ; Where M is the dopant element, G is the coating modifier; D is a metal or metalloid, and f, g, and h satisfy Li f D g O h Valence equilibrium, 0 < x ≤ 10%, 2% < y ≤ 4.2%, 0.05 ≤ a ≤ 0.06, 0.01 < b ≤ 0.03, 0.01 < k ≤ 0.03, 0.04 ≤ c ≤ 0.07, 0.01 < d ≤ 0.06, 0.03 < e ≤ 0.07; The G is Al2O3, Y2O3, AlPO4, LiFePO4, or LiMn. 1-n Fe n PO4, 0 < n < 1, LiNi m Mn 2-m O4, 0<m≤1.0, LiTi2(PO4)3, La2O3, FePO4, LiMnPO4, MnPO4, LiCoPO4, CoPO4, LiNiPO4, NiPO4, Mn 1-n Fe n PO4, 0 < n < 1, Li 1+p Al p Ti 2-p (PO4)3, 0≤p≤1, ZnO, Sb2O3, Bi2O3, Li3AlF6, LiAlF4, LiAlO2, Li4Ti5O 12 At least one of Co3O4 and Sc2O3; or G is an oxide of Ce(OH)4 after decomposition; The method for preparing the single-crystal manganese-based lithium battery cathode material is characterized by comprising the following steps: (1) A portion of the lithium source, nickel source, cobalt source, manganese source, aluminum source, M source and fluorine source are mixed evenly to obtain a mixture WL1; (2) The mixture WL1 obtained in step (1) is decomposed, oxidized, solid-phase melted, crystal nucleated and crystal grown at a temperature of 630~710℃ for 9~17 hours under a protective air atmosphere. The temperature is then raised to 930~990℃ and the crystal is recrystallized for 12~18 hours. The temperature is then lowered to 600~690℃ and the crystal is calcined for repair for 5~8 hours. The temperature is then lowered to room temperature and crushed and sieved to obtain the semi-finished product WL2 with a large single crystal morphology of spinel structure. (3) Weigh a certain amount of G and Li f D g O h After adding water and grinding, a nano-sized mixed slurry WL3 is obtained; (4) Add water to the mixed slurry WL3 obtained in step (3) and mix evenly. Add the remaining lithium source and the semi-finished product WL2 obtained in step (2), and continue to mix evenly for 2 to 6 hours. Dry to obtain mixed material WL4. (5) The mixture WL4 obtained in step (4) is decomposed, recrystallized into single crystals, and reconstructed on the crystal surface in a synthesis sintering furnace under air atmosphere at a temperature of 580~670℃ for 12~17 hours. After cooling to room temperature, the mixture is crushed, sieved, and demagnetized to obtain single crystal manganese-based lithium battery cathode material.

2. The single-crystal manganese-based lithium battery cathode material as described in claim 1, characterized in that, M is an oxide, hydroxide, carbonate, acetate, nitrate, or oxalate of at least one of the following elements: Zr, La-series rare earth elements, Sb, Mg, Nb, Mo, Cr, Ta, Sr, K, Cs, V, Zn, In, Si, Rb, Y, B, Ga, Bi, Sn, Ge, and W.

3. The single-crystal manganese-based lithium battery cathode material as described in claim 1, characterized in that, In step (1), The lithium source is at least one of Li2CO3, LiOH·H2O, Li2C2O4, LiOH, CH3COOLi, C4H9Li, C6H5Li, and LiF. The fluorine source is at least one selected from MgF2, SbF3, CoF2, AlF3, AlF3•3H2O, LiF, GaF3, MnF2, YF3, SrF2, NiF2, MnF3, ZnF2, LaF3, NbF5, SnF2, BaF2, NH4F, LiAlF4, BiF3, ZrF4, CsF, Li3AlF6, and SiF4. The nickel source is at least one of the following: carbonates, oxides, hydroxides, nitrates, fluorides, borides, oxalates, and acetates containing Ni. The cobalt source is at least one of the following: carbonates, oxides, nitrates, hydroxides, fluorides, borides, oxalates, and acetates containing Co. The manganese source is at least one of the following: oxides, hydroxides, carbonates, nitrates, fluorides, borides, oxalates, and acetates containing Mn. The aluminum source is at least one of the following: Al-containing hydroxides, nitrates, fluorides, oxides, acetates, and oxalates.

4. The single-crystal manganese-based lithium battery cathode material as described in claim 1, characterized in that, In step (2), the primary grain size of the semi-finished product WL2 is 1.0~5.0μm.

5. The single-crystal manganese-based lithium battery cathode material as described in claim 1, characterized in that, In step (3), the particle size of the mixed slurry WL3 is 200~800nm; In step (5), the primary grain size of the monocrystalline manganese-based lithium battery cathode material is 1.5~6.0μm.

6. The single-crystal manganese-based lithium battery cathode material as described in claim 1, characterized in that, In step (4), the molar ratio of the remaining lithium to the semi-finished product WL2 is 0.24~0.45∶1.

7. A lithium battery, characterized in that, Includes the single-crystal manganese-based lithium battery cathode material according to any one of claims 1-6.

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