Lithium-rich disordered rock salt polyanionic positive electrode material, composite, and preparation method therefor and use thereof

Abstract

Disclosed are a lithium-rich disordered rock salt polyanionic positive electrode material, and a preparation method therefor and the use thereof. The positive electrode material comprises a lithium-rich disordered rock salt polyanion, having a molecular formula of Li1+aMnbMhO4-f-4gFf(XO4)g, wherein 0.1≤a≤2, 1≤b≤2, 0≤h≤1, 0.0001≤f≤1 and 0.0001≤g≤1; M is selected from one or a combination of more of Cr, Fe, Ni, Co, V, Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re and Si; and X is selected from one or a combination of more of N, P, B, S and Si. The lithium-rich disordered rock salt polyanion can also form a positive electrode material composite with lithium manganese iron phosphate. In the present application, a lithium-rich disordered rock salt material (high capacity) and a polyanion material (high stability) are combined, fluorine is used to dope oxygen, and the lithium-rich disordered rock salt polyanion is also coated with a carbon material, such that the cycle stability of the material can be improved while a high capacity is ensured.

Description

A lithium-rich disordered rock-salt polyanion-based cathode material, a composite and a preparation method and use thereof TECHNICAL FIELD

[0001] The present disclosure relates to a lithium-rich disordered rock-salt polyanion-based cathode material and a preparation method and use thereof. BACKGROUND

[0002] In the lithium ion batteries that have been applied, intercalation-type lithium transition metal (TM) oxides and phosphates are mostly used as cathode materials, including lithium cobaltate and ternary materials with a layered structure, lithium manganate with a spinel structure, and lithium iron phosphate with an olivine structure. However, the actual capacity of these materials is lower than 250 mAh / g, which does not meet the requirements of the next generation of high-energy-density batteries.

[0003] Due to the mixed arrangement between Li and TM in the disordered structure, the diffusion of lithium is limited, and disordered lithium transition metal oxide materials are generally considered to be electrochemically inert. However, with further research, it has been found that if there is sufficient excess lithium (generally more than 10%), lithium ions can migrate through the three-dimensional penetration channel of the lithium diffusion channel (0-TM) with a relatively low migration energy barrier, thereby having isotropic volume change during lithium extraction and having high structural stability. At the same time, due to the excess lithium, there is a Li-O-Li configuration in the material, and the particularity of this structure can activate the oxidation and reduction of anions while the transition metal changes in valence. Lithium-rich materials have much higher capacity and energy density than traditional cathode materials.

[0004] However, due to the oxygen reaction of the lithium-rich disordered rock-salt material, the O-O distance becomes smaller, forming O2 n- . This substance and its instability eventually precipitate in the form of O2, and the irreversibility of this oxygen reaction further causes the destruction of the material structure and the deterioration of the material performance.

[0005] Therefore, how to ensure high capacity and cycle stability at the same time in the design of lithium-rich disordered rock-salt cathode materials is the key to their commercial application. SUMMARY

[0006] In view of the shortcomings and deficiencies of the prior art, the present disclosure provides an improved lithium-rich disordered rock-salt polyanion-based cathode material, which can ensure high capacity while improving its cycle stability, and the cathode material has both high capacity and high cycle stability.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present disclosure is as follows:

[0008] A cathode material comprising a lithium-rich disordered rock-salt polyanion, the molecular formula of the lithium-rich disordered rock-salt polyanion being Li 1+a Mn b Mh O 4-f-4g F f (XO4) g wherein, 0.1≤a≤2, 1≤b≤2, 0≤h≤1, 0.0001≤f≤1, 0.0001≤g≤1; the M is selected from a combination of one or more of Cr, Fe, Ni, Co, V, Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, Si; the X is selected from a combination of one or more of N, P, B, S, Si.

[0009] In the above technical solution, when h=0, it is the following technical solution: a positive electrode material comprising a lithium-rich disordered rock salt polyanion, the positive electrode material further comprising carbon coated on the surface of the lithium-rich disordered rock salt polyanion, and the molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b O 4-f-4g F f (XO4) g wherein, 0.1≤a≤2, 1≤b≤2, 0.0001≤f≤1, 0.0001≤g≤1; the X is selected from a combination of one or more of N, P, B, S, Si. The lithium-rich disordered rock salt polyanion is not doped with other metal cations.

[0010] In the above technical solution, when h≠0, it is the following technical solution: a positive electrode material comprising a lithium-rich disordered rock salt polyanion, characterized in that the positive electrode material further comprises carbon coated on the surface of the lithium-rich disordered rock salt polyanion, and the molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M h O 4-f-4g F f (XO4) g wherein, 0.1≤a≤2, 1≤b≤2, 0<h≤1, 0.0001≤f≤1, 0.0001≤g≤1; the M is selected from a combination of one or more of Cr, Fe, Ni, Co, V, Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, Si; the X is selected from a combination of one or more of N, P, B, S, Si. The lithium-rich disordered rock salt polyanion is doped with other metal cations M.

[0011] wherein 0.1≤a≤2, for example a can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0. 1≤b≤2, for example b can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0. 0≤h≤1, for example h can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. 0.0001≤f≤1, for example f can be 0.0001, 0.0005, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. 0.0001≤g≤1, for example g can be 0.0001, 0.0005, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0.

[0012] In the present disclosure, lithium-rich refers to a material with a relatively high content of lithium element. Generally, the lithium content in a lithium-rich material will exceed the conventional stoichiometric ratio, and the excess lithium helps to improve the electrochemical performance of the material; disordered rock salt structure refers to a material with a face-centered cubic oxygen sublattice arrangement of atoms. In a disordered rock salt structure, the distribution of transition metal ions and lithium ions in the lattice has no obvious long-range order, unlike in some ordered structures, where atoms are arranged in a specific pattern. This disorder has an important impact on the performance of the material, for example, a disordered rock salt positive electrode material relies on the redox reaction of oxygen ions at high voltage to achieve high capacity, but may also bring factors such as gas production that lead to structural instability; polyanion refers to an ionic group with negative charge formed by the combination of multiple atoms through covalent bonds, commonly seen in phosphate, borate, silicate, sulfate, etc. In a lithium-rich disordered rock salt polyanion material, the introduction of polyanion groups is to enhance the stability of the material. The central atom in the polyanion (such as B, P, Si, S, N, etc.) forms a strong covalent bond with oxygen atoms, and when they enter the rock salt structure, the oxygen ions adjacent to the central atom become more stable, significantly reducing the risk of oxygen release, thereby enhancing the structural stability and cycle life of the material.

[0013] In some embodiments, 0.4≤a≤0.8.

[0014] In some embodiments, h=0, and 0.4≤a≤0.8.

[0015] In some embodiments, 0

[0016] In some embodiments, 1.1≤b≤1.6.

[0017] In some embodiments, h=0, and 1.1≤b≤1.6.

[0018] In some embodiments, 0

[0019] In some embodiments, 0.1≤f≤0.5. Controlling the content f of F within this range can further improve the comprehensive electrochemical performance of the positive electrode material.

[0020] In some embodiments, h=0, and 0.1≤f≤0.5.

[0021] In some embodiments, 0

[0022] In some embodiments, 0.05≤g≤0.3. Controlling the content g of XO4 within this range can further improve the comprehensive electrochemical performance of the positive electrode material.

[0023] In some embodiments, h=0, and 0.05≤g≤0.3.

[0024] In some embodiments, 0

[0025] In some embodiments, the positive electrode material further comprises carbon coated on the surface of the lithium-rich disordered rock salt polyanion.

[0026] In some embodiments, the mass percentage of the carbon to the mass of the positive electrode material is 0.1%-10%. Too little coated carbon will reduce the electronic conductivity, increase the material polarization, and reduce the rate performance. Insufficient carbon coating layer will make the electrolyte more likely to have side reactions with the active material, resulting in interface instability and capacity decay. Too much coated carbon will reduce the content of the active material, reduce the capacity of the positive electrode material, and a too thick carbon coating layer will hinder the transmission of lithium ions, reduce the diffusion efficiency of lithium ions, and affect the rate performance.

[0027] In some embodiments, X is selected from P, B, or Si. Preferably, X is P. This is true whether the positive ion M is doped or not.

[0028] In some embodiments, X is selected from P, B, or Si, and 0.05≤g≤0.3. This is true whether the positive ion M is doped or not.

[0029] In some embodiments, the lithium-rich disordered rock salt polyanion has a molecular formula of Li 1.70 Mn 1.40 (PO4) 0.2 O3.0 F 0.2 , Li 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 , Li 1.77 Mn 1.33 (PO4) 0.2 O 2.8 F 0.4 , Li 1.53 Mn 1.57 (PO4) 0.1 O 3.4 F 0.2 , Li 1.78 Mn 1.32 (PO4) 0.25 O 2.8 F 0.2 , Li 1.45 Mn 1.65 (PO4) 0.05 O 3.6 F 0.2 , Li 1.70 Mn 1.31 (PO4) 0.2 O 2.7 F 0.55 , Li 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 .

[0030] For the technical solution doped with metal cation M, the cation doping technology is applied to improve the performance of the lithium-rich disordered rock salt polyanion positive electrode material, in particular:

[0031] In some embodiments, the molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M1 c M2 d M3 e O 4-f-4g F f (XO4) gwherein, 0.1≤a≤2, 1≤b≤2, 0≤c≤1, 0≤d≤1, 0≤e≤1, 0

[0032] wherein, 0.1≤a≤2, for example a can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0. 1≤b≤2, for example b can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0. 0≤c≤1, for example c can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. 0≤d≤1, for example d can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. 0≤e≤1, for example e can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0. 0

[0033] In some embodiments, the lithium-rich disordered rocksalt polyanion has a molecular formula of Li 1+a Mn b M2 d M3 e O 4-f-4g F f (XO4) gwherein 0.1≤a≤2, 1≤b≤2, 0

[0034] wherein 0.1≤a≤2, 1≤b≤2, 0

[0035] In the scheme, the cation doping adjusts the lattice parameters and electronic structure of the material by introducing metal ions (such as Mg, Zn, Al, Nb, etc.) without electrochemical activity, inhibits the occurrence of adverse phase transition and interface side reaction, thereby enhancing the structural stability and electrochemical performance of the material. For example, Al doping can improve the crystal phase stability of the material, Mg doping can help improve the cycle life and rate performance of the material, and Nb can provide charge compensation and increase the number of lithium ions that can be deintercalated; during the deintercalation of lithium, the material can play a role in structural support. The optimized selection of the type and doping ratio of the doping element in the present disclosure can achieve a lithium-rich disordered rock salt polyanion positive electrode material with longer cycle life and better safety. In some embodiments, 0.001≤d≤0.1.

[0036] In some embodiments, 0.001≤e≤0.3.

[0037] In some embodiments, 0.05≤d+e≤0.3. Controlling the total amount of the two types of metal ions in the doping within this range can further optimize the electrical performance of the positive electrode material.

[0038] In some embodiments, M2 is Mg and M3 is Mo or Nb. The combination of the types of metals of M2 and M3 can achieve better electrical performance.

[0039] In some embodiments, the lithium-rich disordered rock salt polyanion has a molecular formula of Li 1+a Mn b M1 c O 4-f-4g F f (XO4) g wherein 0.1≤a≤2, 1≤b≤2, 0<c≤1, 0.0001≤f≤1, 0.0001≤g≤1; the M1 is selected from a combination of one or more of Cr, Fe, Ni, Co, V; the X is selected from a combination of one or more of N, P, B, S, Si.

[0040] In the scheme, the cation doping promotes charge transfer and catalytic oxidation and reduction by introducing metal ions (such as Cr, Fe, Ni, Co, V, etc.) with electrochemical activity. The electroactive metal cations act as "intermediaries" for electron transfer, which can significantly accelerate the oxidation and reduction reaction kinetics of anions (oxygen) and improve the specific capacity of the material. Due to its strong binding ability with oxygen, it can effectively catalyze anion activity, achieve multi-electron reaction, and improve overall electrochemical performance; by occupying transition metal sites, it can effectively inhibit the migration of transition metal ions to the lithium layer, improve the structural stability of the material, and slow down the generation of spinel phase during cycling, thereby improving cycle life and capacity retention.

[0041] In some embodiments, the M1 is V and a combination of at least one selected from Cr, Fe, Ni, Co.

[0042] In some embodiments, the M1 is a combination of Co and V or a combination of Fe and V or a combination of Ni and V.

[0043] In some embodiments, 0.05≤c≤0.5.

[0044] In some embodiments, 0.4≤a≤0.8.

[0045] In some embodiments, 1.1≤b≤1.6.

[0046] In some embodiments, 0.1≤f≤0.5. Controlling the content f of F in this range can further improve the overall electrochemical performance of the positive electrode material.

[0047] In some embodiments, 0.05≤g≤0.3. Controlling the content g of XO4 in this range can further improve the overall electrochemical performance of the positive electrode material.

[0048] In some embodiments, 0.0001≤h≤1. The doped metal element of the positive electrode material can be one or more of the optional species listed for M.

[0049] In some embodiments, 0.05≤h≤0.3. Controlling the amount of doped metal ions in this range can further optimize the electrical performance of the positive electrode material.

[0050] In some embodiments, the M is selected from a combination of two or more of Mg, Zn, Cu, Al. This particular combination of M element species can achieve better electrical performance.

[0051] In some embodiments, the carbon has a mass percentage of 0.1%-10% of the mass of the positive electrode material. Too little coated carbon reduces electronic conductivity, material polarization, and rate performance. Insufficient carbon coating can cause electrolyte to more easily react with active material, leading to interface instability and capacity decay. Too much coated carbon reduces the content of active material, reducing the capacity of the positive electrode material. Too thick a carbon coating layer can hinder the transport of lithium ions, reducing the diffusion efficiency of lithium ions and affecting the rate performance.

[0052] In some embodiments, the X is selected from P, B, or Si. Preferably, X is P.

[0053] In some embodiments, the X is selected from P, B, or Si, and 0.05≤g≤0.3.

[0054] In some embodiments, the lithium-rich disordered rock-salt polyanion has a molecular formula of Li 1.66 Mn 1.28 Mg 0.1 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 , Li 1.70 Mn 1.30 Mg 0.05 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 , Li 1.60 Mn 1.25 Mg 0.2 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 , Li 1.65 Mn 1.30 Mg 0.1 Nb 0.05 (PO4) 0.2 O 3.0 F 0.2 , Li 1.60 Mn 1.30 Mg 0.1 Al 0.1 (PO4) 0.2 O 3.0 F 0.2 , Li 1.71 Mn 1.36 Mg 0.01 Mo 0.02 (PO4) 0.2 O 3.0 F 0.2 , Li 1.77 Mn 0.83 Mg 0.3 Mo 0.1 (PO4) 0.2 O 3.0 F 0.2 , Li 1.72 Mn 1.24 Co 0.05 V 0.1 (PO4) 0.2 O 3.0 F 0.2 , Li 1.70 Mn 1.30 Co 0.05 V 0.05 (PO4) 0.2 O 3.0 F 0.2 , Li 1.73Mn 1.17 Co 0.05 V 0.15 (PO4) 0.2 O 3.0 F 0.2 , Li 1.72 Mn 1.24 Fe 0.05 V 0.10 (PO4) 0.2 O 3.0 F 0.2 , Li 1.73 Mn 1.17 Ni 0.05 V 0.10 (PO4) 0.2 O 3.0 F 0.2 , Li 1.6 Mn 1.15 Fe 0.15 Mg 0.05 Mo 0.05 (PO4) 0.1 O 3.4 F 0.2 or Li 1.8 Mn 1.25 Co 0.1 Mg 0.05 Ti 0.05 Zr 0.05 (PO4) 0.05 O 3.7 F 0.1 .

[0055] The present disclosure also provides a preparation method of the aforementioned positive electrode material, comprising the following steps: 1) mixing a lithium source, a manganese source, a fluorine source, a compound containing an X element, an optional compound containing a metal M element, and optionally water to obtain a mixture; 2) performing ball milling or grinding sintering on the mixture to obtain the lithium-rich disordered rock salt polyanion; and 3) mixing the lithium-rich disordered rock salt polyanion and a carbon source, and performing secondary ball milling or secondary grinding sintering to obtain the positive electrode material. When no metal cation M is doped, no compound containing a metal M element is added, and when a metal cation is doped, a compound containing a metal M element is added as an M source.

[0056] In some embodiments, the preparation method includes the following steps: 1) mechanically mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, and optionally a compound containing element M to obtain a mixture; 2) ball milling and reacting the mixture in a ball mill jar to obtain the lithium-rich disordered rock salt polyanion; 3) mechanically mixing the lithium-rich disordered rock salt polyanion with a carbon source, and then ball milling and reacting the mixture a second time in a ball mill jar to obtain the cathode material. This method does not add water; the raw materials are directly dry-milled after mixing, and a reaction occurs during the milling process to generate lithium-rich disordered rock salt polyanions. These polyanions are then milled with a carbon source and a coating reaction is carried out, which can coat the surface of the lithium-rich disordered rock salt polyanions with carbon. This process does not require solvents, drying, or long sintering steps. The precursors can be uniformly mixed through mechanical force, while refining the powder particles and improving the microstructure of the material. It can also promote the diffusion and uniform distribution of lithium ions through local pressure effects, thereby improving the electrochemical performance of the material. The rate capability and cycle performance of the material are further improved by secondary ball-and-carbon coating.

[0057] In some implementations, in step 1), the rotational speed of the mechanical mixing is 1000-2000 rpm.

[0058] In some embodiments, the mechanical mixing time is 1-10 minutes.

[0059] In some embodiments, in step 2), the ball milling is performed using grinding balls; preferably, the mass ratio of the grinding balls to the mixture is 5-30:1.

[0060] In some embodiments, the grinding beads are made of one or more of zirconium beads, agate beads, and stainless steel beads.

[0061] In some embodiments, the ball milling time is 1-20 hours.

[0062] In some embodiments, the ball mill rotates at a speed of 400-2000 rpm.

[0063] In some implementations, in step 3), the rotational speed of the secondary ball mill is 200-500 rpm.

[0064] In some embodiments, the secondary ball milling time is 0.5-10 hours.

[0065] In some embodiments, the preparation method includes the following steps: 1) mechanically mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, water, and optionally a compound containing element M to obtain a mixture; 2) grinding the mixture to obtain a slurry with a D50 particle size less than or equal to 0.4 μm, spray-drying the slurry to obtain a powder, and sintering the powder in an oxygen atmosphere to obtain the lithium-rich disordered rock salt polyanion; 3) dispersing the lithium-rich disordered rock salt polyanion and a carbon source in an organic solvent by grinding, drying, and then performing solid-phase sintering to obtain the cathode material. This method grinds the raw materials with water to obtain an aqueous slurry, then spray-dries it, and performs solid-phase sintering to obtain lithium-rich disordered rock salt polyanion, which is then solid-phase sintered with a carbon source to obtain the carbon-coated target cathode material. This method is more conducive to industrialization.

[0066] In some implementations, step 2) involves grinding in a sand mill.

[0067] In some embodiments, the sintering temperature in step 2) is 300-700°C.

[0068] In some implementations, the sintering time in step 2) is 1-30 hours.

[0069] In some embodiments, the organic solvent is selected from one or more combinations of NMP (N-methylpyrrolidone), IPA (isopropanol), ACE (acetone), EAC (ethyl acetate), DMAC (dimethylacetamide), and DMF (dimethylformamide).

[0070] In some embodiments, the solid-phase sintering is carried out in a nitrogen atmosphere.

[0071] In some embodiments, in step 3), the solid-state sintering temperature is 100-300°C.

[0072] In some embodiments, in step 3), the solid-state sintering time is 1-10 hours.

[0073] In some embodiments, the lithium source is selected from one or more combinations of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium hydride, lithium nitride, lithium peroxide, lithium chloride, lithium nitrate, lithium sulfate, lithium phosphate, lithium monohydrogen phosphate, lithium dihydrogen phosphate, lithium citrate, lithium laurate, and lithium ascorbate.

[0074] In some embodiments, the manganese source is selected from one or more combinations of manganese dioxide, manganese tetroxide, manganese trioxide, manganese monoxide, lithium hydroxide, manganese carbonate, manganese acetate, manganese sulfate, manganese nitrate, manganese chloride, potassium permanganate, manganese dihydrogen phosphate, manganese oxalate, manganese phosphate, manganese pyrophosphate, and ferromanganese phosphate.

[0075] In some embodiments, the manganese source is a mixture of manganese trioxide and manganese dioxide.

[0076] In some embodiments, the fluorine source is selected from one or more combinations of lithium fluoride, manganese fluoride, magnesium fluoride, sodium fluoride, potassium fluoride, hydrofluoric acid, Freon, and hexafluorophosphate.

[0077] In some embodiments, when X is N, the compound containing element X is a nitrogen source, selected from one or more combinations of ammonium nitrate, lithium nitrate, magnesium nitrate, ferric nitrate, manganese nitrate, guanidine nitrate, cobalt nitrate, aluminum nitrate, copper nitrate, and nickel nitrate. When X is P, the compound containing element X is a phosphorus source, selected from one or more combinations of phosphorus pentoxide, phosphoric acid, pyrophosphate, lithium phosphate, lithium monohydrogen phosphate, lithium dihydrogen phosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, manganese dihydrogen phosphate, sodium phosphate, potassium phosphate, ferric phosphate, manganese phosphate, manganese pyrophosphate, and manganese ferric phosphate. When X is B, the compound containing element X is a boron source, selected from boron oxide, boric acid, boron nitride, boron sulfide, silicon boride, vanadium boride, titanium boride, tungsten boride, molybdenum boride, iron boride, niobium boride, chromium boride, magnesium boride, boron phosphate, and boron. The compound containing element X is selected from one or more combinations of lithium oxide, ammonium fluoroborate, sodium borate, potassium borate, and borate esters. When X is S, the compound containing element X is a sulfur source, and the sulfur source is selected from one or more combinations of sulfuric acid, sulfurous acid, ammonium sulfate, potassium sulfate, sodium sulfate, thiourea, thiols, thioethers, sodium sulfide, boron sulfide, potassium sulfide, iron sulfide, lithium sulfide, magnesium sulfide, manganese sulfide, nickel sulfide, tin sulfide, tungsten sulfide, niobium sulfide, thioacetic acid, potassium thiocyanate, cobalt sulfide, tantalum sulfide, vanadium sulfide, and chromium sulfide. When X is Si, the compound containing element X is a silicon source, and the silicon source is selected from one or more combinations of silicon oxide, silicic acid, silica gel, potassium silicate, silane, silicon nitride, vanadium silicide, tungsten silicide, titanium silicide, cobalt silicide, cobalt silicide, tantalum silicide, iron silicide, manganese silicide, niobium silicide, nickel silicide, diatomaceous earth, lithium silicate, silicon sulfide, silicon boride, silicon carbide, molybdenum silicon powder, and silicone oil.

[0078] In some embodiments, the carbon source is selected from one or more combinations of activated carbon, carbon black, carbon nanotubes, graphite, graphene, and graphene oxide.

[0079] In some embodiments, the compound containing the metal element M (M source) is selected from one or more combinations of oxides, fluorides, carbonates, oxalates, nitrates, sulfates, chlorides, and organic acid salts of the metal element M.

[0080] In some embodiments, the organic acid salt of the metal element M is selected from one or more combinations of its organic phosphates, acetates, organic sulfonates, alkyl salts, and ester salts.

[0081] For example, iron sources can be selected from ferrous oxalate, ferrous acetate, ferric phosphate dihydrate, ferric phosphate, ferric oxide, ferrous sulfate, ferric nitride, ferric phosphide, ferric oxide, ferrous carbonate, ferrocene, ferric oxide, ferric chloride, ferric nitrate, ferric citrate, etc.

[0082] The cobalt source is selected from cobalt(II) oxide, cobalt(III) oxide, cobalt(II) oxide, cobalt acetate tetrahydrate, cobalt oxalate, cobalt carbonate, cobalt hydroxide, cobalt citrate, cobalt nitrate, cobalt sulfate, cobalt chloride, etc.

[0083] The vanadium source is selected from vanadium oxide, ammonium metavanadate, sodium metavanadate, vanadium oxalate, lithium vanadate, vanadium nitride, vanadium chloride, vanadium acid, vanadium fluoride, etc.

[0084] The nickel source is selected from nickel oxide, nickel hydroxide, nickel acetate, nickel carbonate, nickel chloride, nickel nitrate, nickel phosphide, lithium nickelate, nickel sulfide, nickel formate, etc.

[0085] The niobium source is selected from niobium oxide, niobium oxalate, niobium fluoride, niobium hydroxide, niobium nitride, sodium niobate, potassium niobate, lithium niobate, magnesium niobate, niobium chloride, etc.

[0086] The molybdenum source is selected from molybdenum oxide, molybdenum acetate, molybdic acid, molybdenum fluoride, molybdenum boride, molybdenum phosphide, sodium molybdate, potassium molybdate, ammonium molybdate, lithium molybdate, magnesium molybdate, molybdenum disulfide, molybdenum chloride, phosphomolybdic acid, etc.

[0087] The titanium source is selected from titanium oxide, titanium hydroxide, titanium fluoride, metatitanic acid, titanium nitride, titanium sulfate, titanium chloride, lithium titanate, ammonium titanate, potassium titanate, manganese titanate, magnesium titanate, titanium pyrophosphate, etc.

[0088] The tungsten source is selected from tungsten oxide, tungstic acid, sodium tungstate, ammonium tungstate, potassium tungstate, tungsten boride, tungsten carbide, phosphotungstic acid, lithium tungstate, manganese tungstate, magnesium tungstate, tungsten chloride, etc.

[0089] The ruthenium source is selected from ruthenium oxide, ruthenium acetate, ruthenium chloride, etc.

[0090] The tantalum source is selected from tantalum oxide, tantalum phosphide, tantalum fluoride, tantalum nitride, tantalum carbide, lithium tantalate, tantalum chloride, tantalum sulfide, etc.

[0091] The chromium source is selected from chromium acetate, chromium oxide, chromium fluoride, potassium chromate, ammonium chromate, magnesium chromate, chromium nitride, chromium formate, chromium phosphate, chromium boride, chromium chloride, chromium sulfate, chromium nitrate, etc.

[0092] The tin source is selected from tin oxide, tin fluoride, tin acetate, sodium stannate, potassium stannate, stannous sulfate, tin chloride, tin oxalate, etc.

[0093] Magnesium sources are selected from magnesium oxide, magnesium acetate, magnesium chloride, magnesium nitrate, magnesium fluoride, magnesium nitride, magnesium ethanol, magnesium boride, magnesium carbonate, magnesium phosphate, magnesium citrate, magnesium hydroxide, magnesium silicate, magnesium laurate, magnesium sulfate, magnesium gluconate, magnesium oxalate, etc.

[0094] The zinc source is selected from zinc oxide, zinc chloride, zinc sulfate, zinc sulfide, zinc formate, zinc nitride, zinc fluoride, zinc borate, zinc carbonate, zinc laurate, zinc citrate, zinc acetate, zinc phosphate, zinc gluconate, zinc oxalate, etc.

[0095] The copper source is selected from copper oxide, copper chloride, copper sulfate, copper nitrate, copper sulfide, copper silicide, copper bromide, copper iodide, copper oxalate, copper citrate, copper hydroxide, copper tartrate, copper acetate, copper phosphate, etc.

[0096] The aluminum source is selected from alumina, aluminum fluoride, aluminum nitride, aluminum sulfide, aluminum sulfate, aluminum phosphate, aluminum titanate, lithium aluminate, trimethylaluminum, lithium aluminum hydride, aluminum hydroxide, aluminum diboride, aluminum isopropoxide, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum oxalate, etc.

[0097] The amount of each raw material fed is determined based on the molecular formula composition of the final target cathode material.

[0098] This disclosure also provides a cathode material composite, the composite comprising the aforementioned cathode material and lithium manganese iron phosphate; the lithium manganese iron phosphate having the molecular formula LiMn 1-x-y Fe x M' y PO4, wherein M' is one or more of Mg, Ti, V, Cr, Co, Ni, Zn, Ga, Al, Zr, Nb, Mo, Sn, Sb, Ca, Ba, Si, B, Ru, Si, Te, and Cu, and 0.01≤x≤0.98, 0≤y≤0.1.

[0099] This disclosure combines the aforementioned lithium-rich disordered rock salt polyanion and lithium manganese iron phosphate to obtain a composite cathode material that can simultaneously possess high specific capacity and good cycle stability.

[0100] Lithium-rich disordered rock salt polyanions can be doped or undoped; when h is 0, it is undoped, and when h is not 0, it is doped. Lithium manganese iron phosphate can also be doped or undoped; when y is 0, it is undoped, and when y is not 0, it is doped.

[0101] In some embodiments, the mass ratio of the lithium-rich disordered rock salt polyanion to lithium manganese iron phosphate is 1-5:5-9; preferably 1-2:8-9.

[0102] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon.

[0103] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon at a mass percentage of 0.1%-10%. Insufficient carbon coating reduces electronic conductivity, increases material polarization, and lowers rate performance. A lack of sufficient carbon coating also makes the electrolyte more susceptible to side reactions with the active material, leading to interfacial instability and capacity decay. Excessive carbon coating reduces the content of active material, lowers the capacity of the cathode material, and an overly thick carbon coating hinders lithium-ion transport, reduces lithium-ion diffusion efficiency, and affects rate performance.

[0104] In some embodiments, the surface of the lithium manganese iron phosphate is coated with carbon.

[0105] In some embodiments, the surface of the lithium manganese iron phosphate is coated with carbon at a mass percentage of 0.1% to 10%.

[0106] In some implementations, 0.4 ≤ a ≤ 0.8.

[0107] In some implementations, 1.1 ≤ b ≤ 1.6.

[0108] In some implementations, 0.1 ≤ f ≤ 0.5. Controlling the F content f within this range can further improve the overall electrochemical performance of the cathode material.

[0109] In some embodiments, 0.05 ≤ g ≤ 0.3 g. Controlling the XO4 content within this range can further improve the overall electrochemical performance of the cathode material.

[0110] In some embodiments, X is selected from P, B, or Si. Preferably, X is P.

[0111] In some embodiments, X is selected from P, B or Si, and 0.05 ≤ g ≤ 0.3.

[0112] In some embodiments, the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M1 c M2 d M3 e O 4-f-4g F f (XO4) gWherein, 0.1≤a≤2, 1≤b≤2, 0≤c≤1, 0≤d≤1, 0≤e≤1, 0<c+d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M1 is selected from one or more combinations of Cr, Fe, Ni, Co, and V; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si. The doping elements of the lithium-rich disordered rock salt polyanion can be M1, M2, M3, etc.

[0113] In some embodiments, the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M2 d M3 e O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0<d≤1, 0<e≤1, 0<d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si. The doping elements of lithium-rich disordered rock salt polyanions can be M2, M3, etc.

[0114] In some embodiments, M is selected from one or more combinations of Cr, Fe, Ni, Co, and V.

[0115] In some implementations, M is selected from one or both of Fe and V.

[0116] In some implementations, 0.001 ≤ h ≤ 0.3; preferably, 0.05 ≤ h ≤ 0.3.

[0117] In some implementations, h = 0.

[0118] In some implementations, M is Fe and V, and 0.05 ≤ h ≤ 0.3.

[0119] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon accounting for 0.1%-10% of its mass, the surface of the lithium manganese iron phosphate is coated with carbon, the surface of the lithium manganese iron phosphate is coated with carbon accounting for 0.1%-10% of its mass, and M is Fe and V, 0.05≤h≤0.3.

[0120] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon accounting for 0.1%-10% of its mass, the surface of the lithium manganese iron phosphate is coated with carbon, the surface of the lithium manganese iron phosphate is coated with carbon accounting for 0.1%-10% of its mass, and h=0.

[0121] In some embodiments, M' is one or more combinations selected from Mg, Ca, Ba, and Si.

[0122] In some implementations, 10 -4 ≤y≤0.1; preferably 0.01≤y≤0.1.

[0123] In some implementations, y = 0.

[0124] In some embodiments, M' is one or more combinations selected from Mg, Ca, Ba, and Si, and 0.01≤y≤0.1.

[0125] In some implementations, M' is Mg, and 0.01 ≤ y ≤ 0.1.

[0126] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon accounting for 0.1%-10% of its mass, the surface of the lithium manganese iron phosphate is coated with carbon, the surface of the lithium manganese iron phosphate is coated with carbon accounting for 0.1%-10% of its mass, and M' is Mg, and 0.01≤y≤0.1.

[0127] In some embodiments, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon, the surface of the lithium-rich disordered rock salt polyanion is coated with carbon accounting for 0.1%-10% of its mass, the surface of the lithium manganese iron phosphate is coated with carbon, the surface of the lithium manganese iron phosphate is coated with carbon accounting for 0.1%-10% of its mass, and its y=0.

[0128] This disclosure also provides a method for preparing the aforementioned cathode material composite, the method comprising the step of mixing the lithium-rich disordered rock salt polyanion and lithium manganese iron phosphate.

[0129] Furthermore, the mixing is carried out in a high-speed mixer.

[0130] Furthermore, the mixing speed is 1000-2000 r / min.

[0131] Furthermore, the mixing time is 10-30 minutes.

[0132] For the preparation of lithium manganese iron phosphate (without M' element or with M' element), conventional preparation methods in this field can be used.

[0133] This disclosure also provides a lithium-ion battery comprising the aforementioned cathode material or the aforementioned cathode material composite.

[0134] Furthermore, the lithium-ion battery exhibits a discharge specific capacity of 200-350 mAh / g at a current of 10 mA / g, and a discharge specific capacity of over 150-300 mAh / g at a current of 100 mA / g. After 200 charge-discharge cycles at a current of 150 mA / g, the capacity retention rate is 60%-90%. This demonstrates that the lithium-ion battery possesses excellent high capacity and high cycle stability.

[0135] Furthermore, the lithium-ion battery exhibits a discharge specific capacity of 220-270 mAh / g at a current of 10 mA / g, and a discharge specific capacity of over 150-200 mAh / g at a current of 100 mA / g. After 200 charge-discharge cycles at a current of 150 mA / g, the capacity retention rate is 60%-72%. This performance can be achieved using undoped lithium-rich disordered rock salt polyanionic cathode material.

[0136] Furthermore, the lithium-ion battery exhibits a discharge specific capacity of 240-310 mAh / g at a current of 10 mA / g, a discharge specific capacity of over 180-260 mAh / g at a current of 100 mA / g, and a capacity retention rate of 68%-80% after 200 charge-discharge cycles at a current of 150 mA / g. This performance can be achieved using a lithium-rich disordered rock salt polyanionic cathode material doped with metal cation M.

[0137] Furthermore, the lithium-ion battery exhibits a discharge specific capacity of 160-180 mAh / g at 10 mA / g, 160-180 mAh / g at 30 mA / g, and 140-170 mAh / g at 30 mA / g. After 200 charge-discharge cycles at 150 mA / g, the capacity retention rate is 90%-99%. This performance can be achieved using a lithium-rich disordered rock salt polyanion and lithium manganese iron phosphate composite cathode material.

[0138] Compared with the prior art, this disclosure has the following advantages:

[0139] The lithium-rich disordered rock salt polyanionic cathode material disclosed herein can improve its cycle stability while ensuring high capacity. The cathode material has both high capacity and high cycle stability.

[0140] The lithium-rich disordered rock salt polyanionic cathode material doped with metal cation M disclosed herein can improve its cycle stability, especially its cycle performance under high voltage, while ensuring high capacity.

[0141] The composite cathode material disclosed herein can leverage the complementary advantages of lithium-rich disordered rock salt cathode materials and traditional manganese iron phosphate cathode materials.

[0142] It has both high specific capacity and good cycle stability. Attached Figure Description

[0143] Figure 1 shows a SEM image of the cathode material prepared in Example 1, with different scales.

[0144] Figure 2 shows the XRD pattern of the cathode material prepared in Example 1;

[0145] Figure 3 shows the charge-discharge curves of the cathode material prepared in Example 1 at a current of 10 mA / g.

[0146] Figure 4 shows the cycling curve of the cathode material prepared in Example 1 at a current of 150 mA / g;

[0147] Figure 5 shows the SEM images of the cathode material prepared in Example 12, with different scales.

[0148] Figure 6 shows the XRD pattern of the cathode material prepared in Example 12;

[0149] Figure 7 shows the charge-discharge curves of the cathode material prepared in Example 12 at a current of 10 mA / g.

[0150] Figure 8 shows the cycling curve of the cathode material prepared in Example 12 at a current of 150 mA / g.

[0151] Figure 9 shows the SEM images of the cathode material prepared in Example 28, with different scales.

[0152] Figure 10 shows the XRD pattern of the cathode material prepared in Example 28;

[0153] Figure 11 is a SEM image of the cathode material prepared in Example 29, with different scales.

[0154] Figure 12 shows the XRD pattern of the cathode material prepared in Example 29;

[0155] Figure 13 shows the charge-discharge curves of the cathode materials prepared in Example 29 and Comparative Example 4 at a current of 0.03C.

[0156] Figure 14 shows the cycling curve of the cathode material prepared in Example 29 at a current of 0.5C. Detailed Implementation

[0157] In recent years, lithium-rich disordered rock salt cathode materials have attracted much attention due to their high capacity and high voltage characteristics, but they have encountered many challenges in practical applications, especially insufficient cycle stability and oxygen release problems. To address these challenges, this disclosure proposes a strategy of simultaneously introducing polyanionic groups and fluoride ions into lithium-rich disordered rock salt cathode materials, thereby improving the overall performance of the material through structural optimization.

[0158] The high capacity advantage of lithium-rich disordered rock salt cathode materials is mainly attributed to their unique "O" structure. 2- / O2 n- The redox mechanism provides an additional source of capacity. During charge and discharge, the reversible redox reaction of oxygen ions significantly improves the battery's energy density. However, under high voltage conditions, these materials are prone to oxygen release, which not only reduces cycle stability but also limits their rate performance. Furthermore, the long diffusion path of oxygen ions in the lithium-rich disordered rock salt structure further restricts performance.

[0159] To overcome these challenges, this disclosure firstly enhances the structural stability and electrochemical performance of the material by introducing polyanionic groups. Polyanionic groups are typically composed of transition metals and oxygen elements, which not only possess good electrochemical stability but also high electronic conductivity. For example, phosphate (PO4) groups... 3- The ) group, due to its strong covalent bond characteristics, can significantly enhance the stability of the crystal lattice. Furthermore, the fluoride ion (F) - Due to its high electronegativity, it can more effectively bind transition metal ions, thereby improving overall stability and increasing oxygen vacancies, reducing irreversible oxygen loss. Therefore, embedding phosphate and fluoride ions into the lithium-rich disordered rock salt structure can effectively reduce the instability of oxygen ions.

[0160] Secondly, this disclosure combines lithium-rich disordered rock salt materials (high capacity) and polyanionic materials (high stability), and uses fluorine to dope oxygen, while simultaneously coating the lithium-rich disordered rock salt polyanionic material with carbon material. By employing fluorine doping and carbon coating modification, the discharge specific capacity and cycle performance of the material can be further improved, enabling the material to possess two properties that are difficult to achieve simultaneously in existing technologies.

[0161] Among these, the doping of F anions is beneficial because F anions have a lower valence state than O ions, which can improve charge compensation and increase the number of lithium ions that can be inserted or extracted. F has strong electronegativity, enabling it to form stronger covalent bonds with metal ions, thereby improving the stability of metal ions in the crystal structure and reducing metal ion dissolution. F can also increase the number of oxygen vacancies in the material, reducing irreversible oxygen loss due to reactions. For carbon coating, the material particles are uniformly coated with carbon material, or carbon material is doped between the particles. This not only improves the conductivity of the material, resulting in high-rate, high-capacity cathode materials, but also helps protect the surface structure of the material and reduces side reactions between the material interface and the electrolyte.

[0162] Furthermore, this disclosure modifies lithium-rich disordered rock salt cathode materials by doping with metal cations M. Another innovation of this disclosure, compared to the scheme of introducing electrochemically inactive metal ions for doping, lies in doping the lithium-rich disordered rock salt polyanionic cathode material with metal element ions M. M can be selected from Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, Si, etc. This element M cannot change its valence and is a high-valence metal ion. It has no electrochemical activity but can improve charge compensation and increase the number of lithium ions that can be inserted and extracted. During the lithium insertion and extraction process, this doped high-valence metal ion can play a structural supporting role, improving the stability of the material. In other words, this disclosure, by further doping with specific M element metal ions, can further improve the performance of the cathode material, especially its cycle performance under high voltage.

[0163] For doping schemes involving the introduction of electrochemically active metal ions, M can be selected from one or more combinations of Cr, Fe, Ni, Co, and V. This element has variable valence, is electrochemically active, and is present in the anion (O). 2 -) It acts as an "electron transfer intermediary" in the redox reaction, promotes the charge transfer process, improves the reversible capacity of the material, enhances the bonding energy between transition metals and oxygen, reduces the formation of oxygen vacancies during charging and discharging, and inhibits capacity decay and safety issues caused by oxygen release.

[0164] Finally, this disclosure also innovatively combines lithium-rich disordered rock salt polyanionic cathode material with traditional lithium manganese iron phosphate cathode material. The resulting composite material can achieve complementary advantages of the two materials and improve the overall electrochemical performance of the composite material.

[0165] Lithium-rich disordered rock salt materials possess high specific capacity and high energy density, and exhibit good structural stability. However, they suffer from severe oxygen loss under high voltage, leading to poor stability. In contrast, lithium manganese iron phosphate, with its olivine structure similar to lithium iron phosphate and a higher discharge platform (approximately 4.1V), demonstrates better cycle stability. Therefore, by leveraging the complementary advantages of both materials, the composite material proposed in this application can simultaneously achieve high specific capacity and good cycle stability.

[0166] The present disclosure will be further described below with reference to embodiments. However, the present disclosure is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present disclosure can be combined with each other as long as they do not conflict with each other.

[0167] Example 1

[0168] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 @C:

[0169] Weigh the raw materials: 5.0 kg deionized water, 377.68 g LiOH·H2O, 394.70 g Mn2O3, 782.43 g MnO2, 231.59 g Li3PO4, 51.88 g LiF was added sequentially to the feeding tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The milled slurry was spray-dried into powder, which was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of carbon nanotubes were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0170] The SEM and XRD patterns of the material are shown in Figures 1-2, respectively. It can be seen that the primary particle size of the lithium-rich rock salt polyanionic material is approximately 100-150 nm. The uniform mixing of carbon nanotubes and lithium-rich materials significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0171] Example 2:

[0172] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 @C:

[0173] Weigh the raw materials: 5.0 kg deionized water, 405.37 g LiOH·H2O, 394.70 g Mn2O3, 811.99 g MnO2, 231.59 g Li3PO4, 25.94 g LiF was processed by sequentially adding each raw material into a sand mill feed tank and milling until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of carbon nanotubes were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0174] The primary particle size of the carbon-coated lithium-rich disordered rock salt polyanionic material obtained is approximately 100-150 nm, and the carbon nanotubes are uniformly mixed with the lithium-rich material; the XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0175] Example 3:

[0176] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.77 Mn 1.33 (PO4) 0.2 O2.8 F 0.4 @C:

[0177] Weigh the raw materials: 5.0 kg deionized water, 321.78 g LiOH·H2O, 394.70 g Mn2O3, 724.36 g MnO2, 231.59 g Li3PO4, 103.76 g LiF was processed by sequentially adding each raw material into a sand mill feed tank and milling until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product, along with 0.51g of carbon nanotubes and 0.5g of graphene, were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0178] The primary particle size of the carbon-coated lithium-rich disordered rock salt polyanionic material obtained is approximately 100-150 nm, and the carbon nanotubes are uniformly mixed with the lithium-rich material; the XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0179] Example 4:

[0180] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.53 Mn 1.57 (PO4) 0.1 O 3.4 F 0.2 @C:

[0181] Weigh the raw materials: 5.0 kg deionized water, 433.70 g LiOH·H2O, 394.70 g Mn2O3, 927.18 g MnO2, 115.79 g Li3PO4, 51.88 g LiF was processed by sequentially adding each raw material into a sand mill feed tank and milling until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of graphene were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0182] The resulting carbon-coated lithium-rich disordered rock salt polyanionic material has a primary particle size of approximately 100-150 nm, and graphene is uniformly mixed with the lithium-rich material. The XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0183] Example 5:

[0184] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.78 Mn 1.32 (PO4) 0.25 O 2.8 F 0.2 @C:

[0185] Weigh the following raw materials: 5.0 kg deionized water, 349.68 g LiOH·H2O, 394.70 g Mn2O3, 710.01 g MnO2, 289.49 g Li3PO4, 51.88 g LiF was processed by sequentially adding each raw material into a sand mill feed tank and milling until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of graphene were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0186] The resulting carbon-coated lithium-rich disordered rock salt polyanionic material has a primary particle size of approximately 100-150 nm, and graphene is uniformly mixed with the lithium-rich material. The XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0187] Example 6:

[0188] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.45 Mn 1.65 (PO4) 0.05 O 3.6 F 0.2 @C:

[0189] Weigh the raw materials: 5.0 kg deionized water, 461.60 g LiOH·H2O, 394.70 g Mn2O3, 999.78 g MnO2, 57.90 g Li3PO4 and 51.88g LiF were sequentially added to the feed tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of graphene were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0190] The resulting carbon-coated lithium-rich disordered rock salt polyanionic material has a primary particle size of approximately 100-150 nm, and graphene is uniformly mixed with the lithium-rich material. The XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0191] Example 7:

[0192] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.70 Mn 1.31 (PO4) 0.2 O 2.65 F 0.55 @C:

[0193] Weigh the raw materials: 5.0 kg deionized water, 230.80 g LiOH·H2O, 394.70 g Mn2O3, 706.36 g MnO2, 231.59 g Li3PO4, 142.66 g LiF was added sequentially to the feeding tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The milled slurry was spray-dried into powder, which was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of carbon nanotubes were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0194] The primary particle size of the carbon-coated lithium-rich disordered rock salt polyanionic material obtained is approximately 100-150 nm, and the carbon nanotubes are uniformly mixed with the lithium-rich material; the XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0195] Example 8:

[0196] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.70 Mn 1.24 (PO4) 0.35 O 2.5 F 0.1 @C:

[0197] Weigh the raw materials: 5.0 kg deionized water, 230.80 g LiOH·H2O, 394.70 g Mn2O3, 641.25 g MnO2, 405.28 g Li3PO4, 25.94 g LiF was added sequentially to the feeding tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4μm. The slurry was then dried using a spray dryer with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The milled slurry was spray-dried into powder, which was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 300mL / min, a sintering temperature of 400℃, and a sintering time of 10h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of carbon nanotubes were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200℃ for 5 hours under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0198] The primary particle size of the carbon-coated lithium-rich disordered rock salt polyanionic material obtained is approximately 100-150 nm, and the carbon nanotubes are uniformly mixed with the lithium-rich material; the XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0199] Example 9:

[0200] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 @C:

[0201] Weigh out the following raw materials: 13.446g Li₂O, 39.470g Mn₂O₃, 78.243g MnO₂, 23.159g Li₃PO₄, and 5.188g LiF. Place all raw materials in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (zirconium beads to material weight ratio 20:1), seal well, and perform high-energy ball milling reaction (800 rpm, 10 hours). Weigh out 100g of the ball-milled material and 5.263g of carbon black, mix them mechanically until uniform, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain carbon-coated lithium-rich disordered rock salt polyanionic material Li. 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 @C. C is coated on the material, accounting for approximately 5% of the mass of the cathode material.

[0202] The primary particle size of the obtained lithium-rich rock salt polyanionic material is approximately 150-400 nm. The uniform mixing of carbon black and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0203] Example 10:

[0204] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 @C:

[0205] Weigh the following raw materials: 14.443g Li₂O, 39.470g Mn₂O₃, 81.199g MnO₂, 23.159g Li₃PO₄, and 2.594g LiF. Place all raw materials in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (zirconium beads to material weight ratio 20:1), seal well, and perform high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100g of the ball-milled material and 1.01g of carbon nanotubes, mix them mechanically until uniform, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain carbon-coated lithium-rich disordered rock salt polyanionic material Li. 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 @C. C is coated on the material, accounting for approximately 1% of the mass of the cathode material.

[0206] The primary particle size of the obtained lithium-rich rock salt polyanionic material is approximately 150-400 nm. The uniform mixing of carbon black and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0207] Example 11:

[0208] This embodiment provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, and the chemical formula is Li. 1.77 Mn 1.33 (PO4) 0.2 O 2.8 F 0.4 @C:

[0209] Weigh the following raw materials: 14.452g Li₂O, 39.470g Mn₂O₃, 72.462g MnO₂, 23.159g Li₃PO₄, and 10.376g LiF. Place all raw materials in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (zirconium beads to material weight ratio 20:1), seal well, and perform high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100g of the ball-milled material and 5.263g of carbon black, mix them mechanically until uniform, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain carbon-coated lithium-rich disordered rock salt polyanionic material Li. 1.77 Mn 1.33 (PO4) 0.2 O 2.8 F 0.4 @C. C is coated on the material, accounting for approximately 5% of the mass of the cathode material.

[0210] The primary particle size of the obtained lithium-rich rock salt polyanionic material is approximately 150-400 nm. The uniform mixing of carbon black and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0211] Comparative Example 1

[0212] This comparative example provides a comparative lithium-rich disordered rock salt polyanionic material, the preparation process of which is basically the same as in Example 1, except that LiF is not added to the raw materials, and the amount of LiOH·H2O is adjusted to 461.60 g, finally yielding Li 1.70 Mn 1.40 (PO4) 0.2 O 3.2 @C cathode material.

[0213] Comparative Example 2

[0214] This comparative example provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is basically the same as in Example 1, the only difference being that a carbon coating process is not performed, ultimately yielding Li... 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 Positive electrode material.

[0215] Comparative Example 3

[0216] This comparative example provides a lithium-rich disordered rock salt polyanionic material, the preparation process of which is basically the same as in Example 1, except that the amount of carbon nanotubes is adjusted to 11.236g, and the final mass percentage of carbon nanotubes in the cathode material is 11.0%.

[0217] The above-mentioned positive electrode materials were combined with conductive carbon nanotubes, conductive carbon black, polyvinylidene fluoride (PVDF) binder, and N-methylpyrrolidone (N-Methylpyrrolidone) solvent to form a positive electrode slurry, wherein the mass ratio of the positive electrode material, conductive carbon black, and PVDF binder was 70:20:10. The positive electrode slurry was coated onto aluminum foil, then vacuum baked, stamped, and finally formed into a positive electrode sheet. Using this positive electrode sheet as the positive electrode, a lithium sheet as the negative electrode, and a 1 mol / L LiPF6 DEC / EC / EMC solution as the electrolyte, a button cell battery was assembled. The battery was then subjected to charge-discharge tests (charge-discharge window of 1.5V to 4.8V) to obtain the electrical performance of the lithium-rich disordered rock salt polyanion. The results are shown in Table 1 below. The charge-discharge curves (at 10 mA / g current) and cycle curves (at 150 mA / g current) of Example 1 are shown in Figures 3-4, respectively.

[0218] Table 1

[0219] It is evident that the lithium-rich disordered rock salt polyanionic material of this application possesses high discharge specific capacity and cycle performance.

[0220] Example 12

[0221] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, with the chemical formula Li. 1.66 Mn 1.28 Mg 0.1 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 @C:

[0222] Weigh the following raw materials: 12.946g Li₂O, 39.470g Mn₂O₃, 68.115g MnO₂, 23.159g Li₃PO₄, 4.030g MgO, 5.188g LiF, and 7.198g MoO₃. Place all raw materials in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (zirconium beads to material weight ratio 20:1), seal well, and perform a high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100g of the ball-milled material and 1.01g of single-walled carbon nanotubes, mix them mechanically until uniform, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material. The SEM and XRD patterns of the material are shown in Figures 5-6, respectively. It can be seen that the primary particle size of the obtained doped lithium-rich rock salt polyanionic material is approximately 150-400 nm. The uniform mixing of single-walled carbon nanotubes with the lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0223] Example 13

[0224] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.70 Mn 1.30 Mg 0.05 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 @C, its preparation process is basically the same as in Example 1, the only difference being that the raw materials are not exactly the same, specifically: 13.446g Li2O, 39.470g Mn2O3, 69.550g MnO2, 23.159g Li3PO4, 2.015g MgO, 5.188g LiF, and 7.198g MoO3. The carbon coating process is the same as in Example 12, finally obtaining a carbon-coated lithium-rich disordered rock salt polyanionic material. C is coated on the material, accounting for approximately 1% of the mass percentage of the cathode material.

[0225] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of single-walled carbon nanotubes with the lithium-rich material significantly improves its electrical conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0226] Example 14

[0227] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.60 Mn 1.25 Mg 0.2 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, the raw materials are: 11.952g Li2O, 39.470g Mn2O3, 65.203g MnO2, 23.159g Li3PO4, 8.061g MgO, 5.188g LiF, and 7.198g MoO3. The carbon coating process is the same as in Example 12, and finally, a carbon-coated lithium-rich disordered rock salt polyanionic material is obtained. The C coating accounts for approximately 1% of the mass of the cathode material.

[0228] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of single-walled carbon nanotubes with the lithium-rich material significantly improves its electrical conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0229] Example 15

[0230] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.65 Mn 1.30 Mg 0.1 Nb 0.05 (PO4) 0.2 O 3.0 F 0.2@C, its preparation process is basically the same as in Example 12, the only difference being that the raw materials are not exactly the same, specifically: 12.699g Li2O, 39.470g Mn2O3, 69.550g MnO2, 23.159g Li3PO4, 4.030g MgO, 5.188g LiF and 6.645g Nb2O5.

[0231] 100g of the ball-milled material and 5.263g of carbon black were weighed and mechanically mixed evenly; then the mixture was placed in a ball mill jar for ball milling reaction (400 r / min, 5 h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 5% of the mass of the cathode material.

[0232] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of carbon black and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0233] Example 16

[0234] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.60 Mn 1.30 Mg 0.1 Al 0.1 (PO4) 0.2 O 3.0 F 0.2 @C, its preparation process is basically the same as in Example 12, the only difference being that the raw materials are not exactly the same, specifically: 11.952g Li2O, 39.470g Mn2O3, 69.550g MnO2, 23.159g Li3PO4, 4.030g MgO, 5.188g LiF and 5.098g Al2O3.

[0235] 100g of the ball-milled material and 5.263g of carbon black were weighed and mechanically mixed evenly; then the mixture was placed in a ball mill jar for ball milling reaction (400 r / min, 5 h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 5% of the mass of the cathode material.

[0236] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of carbon black and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0237] Example 17

[0238] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, with the chemical formula Li. 1.66 Mn 1.28 Mg 0.1 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 @C:

[0239] Weigh the raw materials: 6.0 kg deionized water, 883.97 g CH3COOLi·2H2O, 394.70 g Mn2O3, 681.15 g MnO2, 231.59 g Li3PO4, 51.88 g LiF, 40.30g MgO, and 71.98g MoO3 were added sequentially to the feed tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4μm. The slurry was then spray-dried into powder using a sprayer with an inlet air temperature of 230℃ and an outlet air temperature of 100℃. The powder was then sintered in a tube furnace under an oxygen atmosphere at a flow rate of 400mL / min, a sintering temperature of 450℃, and a sintering time of 20h (heating rate 5℃ / min) to obtain the calcined material. 100g of the sintered product and 1.01g of graphene were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 250℃ for 10h under a nitrogen atmosphere to obtain the target carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0240] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 100-150 nm. The uniform mixing of graphene and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0241] Example 18

[0242] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.70 Mn 1.30 Mg 0.05 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 @C, its preparation process is basically the same as in Example 17, the only difference being that the raw materials are not exactly the same, specifically:

[0243] 6.0 kg deionized water, 918.14 g CH3COOLi·2H2O, 394.70 g Mn2O3, 695.50 g MnO2, 231.59 g Li3PO4, 51.88 g LiF, 20.15 g MgO, and 71.98 g MoO3 were used. The carbon coating process was the same as in Example 17, finally yielding a lithium-rich disordered rock salt polyanionic material with the target carbon coating. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0244] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 100-150 nm. The uniform mixing of graphene and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0245] Example 19

[0246] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.60 Mn 1.25 Mg 0.2 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2@C, its preparation process is basically the same as in Example 17, the only difference being that the raw materials are not exactly the same, specifically: 6.0 kg deionized water, 816.13 g CH3COOLi·2H2O, 394.70 g Mn2O3, 652.03 g MnO2, 231.59 g Li3PO4, 51.88 g LiF, 80.61 g MgO, and 71.98 g MoO3. The carbon coating process is the same as in Example 6, finally obtaining the target carbon-coated lithium-rich disordered rock salt polyanionic material. C is coated on the material, accounting for approximately 1% of the mass percentage of the cathode material.

[0247] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 100-150 nm. The uniform mixing of graphene and lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0248] Example 20

[0249] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.71 Mn 1.36 Mg 0.01 Mo 0.02 (PO4) 0.2 O 3.0 F 0.2 @C, its preparation process is basically the same as in Example 12, the only difference being that the raw materials are not exactly the same, specifically:

[0250] The following materials were used: 13.544g Li₂O, 39.470g Mn₂O₃, 75.070g MnO₂, 23.159g Li₃PO₄, 0.403g MgO, 5.188g LiF, and 2.879g MoO₃. The carbon coating process was the same as in Example 12, resulting in a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounted for approximately 1% of the mass of the cathode material.

[0251] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of single-walled carbon nanotubes with the lithium-rich material significantly improves its electrical conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0252] Example 21

[0253] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.77 Mn 0.83 Mg 0.3 Mo 0.1 (PO4) 0.2 O 3.0 F 0.2 The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, the raw materials are: 11.452g Li2O, 39.470g Mn2O3, 55.075g MnO2, 23.159g Li3PO4, 12.091g MgO, 5.188g LiF, and 14.396g MoO3. The carbon coating process is the same as in Example 12, and finally, a carbon-coated lithium-rich disordered rock salt polyanionic material is obtained. The C coating on the material accounts for approximately 1% of the mass of the cathode material.

[0254] The resulting doped lithium-rich rock salt polyanionic material has a primary particle size of approximately 150-400 nm. The uniform mixing of single-walled carbon nanotubes with the lithium-rich material significantly improves its electrical conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material retains the structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0255] Example 22

[0256] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.72 Mn 1.24 Co 0.05 V 0.1 (PO4) 0.2 O 3.0 F 0.2The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, the raw materials are: 13.693g Li2O, 39.470g Mn2O3, 63.768g MnO2, 23.159g Li3PO4, 9.094g V2O5, 5.188g LiF, and 4.147g Co2O3. 100.00g of the ball-milled material and 1.00g of carbon black were weighed and mechanically mixed evenly; then the mixture was placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0257] Example 23

[0258] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.70 Mn 1.30 Co 0.05 V 0.05 (PO4) 0.2 O 3.0 F 0.2 The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, they are: 13.446g Li2O, 39.470g Mn2O3, 69.550g MnO2, 23.159g Li3PO4, 4.547g V2O5, 5.188g LiF, and 4.147g Co2O3. 100.00g of the ball-milled material and 1.00g of carbon black are weighed and mechanically mixed evenly; then the mixture is placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0259] Example 24

[0260] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.73 Mn 1.17 Co 0.05 V 0.15 (PO4) 0.2 O 3.0 F 0.2The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, the raw materials are: 13.948g Li2O, 39.470g Mn2O3, 57.935g MnO2, 23.159g Li3PO4, 13.641g V2O5, 5.188g LiF, and 4.147g Co2O3. 100.00g of the ball-milled material and 1.00g of carbon black are weighed and mechanically mixed evenly; then the mixture is placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. The carbon coating on the material accounts for approximately 1% of the mass of the cathode material.

[0261] Example 25

[0262] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.72 Mn 1.24 Fe 0.05 V 0.10 (PO4) 0.2 O 3.0 F 0.2 The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, they are: 13.696g Li2O, 39.470g Mn2O3, 63.751g MnO2, 23.159g Li3PO4, 9.094g V2O5, 5.188g LiF, and 3.992g Fe2O3. 100.00g of the ball-milled material and 1.00g of carbon black are weighed and mechanically mixed evenly; then the mixture is placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. C is coated on the material, accounting for approximately 1% of the mass of the cathode material.

[0263] Example 26

[0264] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.73 Mn 1.17 Ni 0.05 V 0.10 (PO4) 0.2 O 3.0 F 0.2The preparation process of @C is basically the same as in Example 12, except that the raw materials are not exactly the same. Specifically, they are: 13.696g Li2O, 39.470g Mn2O3, 63.751g MnO2, 23.159g Li3PO4, 9.094g V2O5, 5.188g LiF, and 4.136g Ni2O3. 100.00g of the ball-milled material and 1.00g of carbon black are weighed and mechanically mixed evenly; then the mixture is placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally yielding a carbon-coated lithium-rich disordered rock salt polyanionic material. C is coated on the material, accounting for approximately 1% of the mass of the cathode material.

[0265] Example 27

[0266] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material with the chemical formula Li. 1.6 Mn 1.15 Fe 0.15 Mg 0.05 Mo 0.05 (PO4) 0.1 O 3.4 F 0.2 @C, its preparation process is basically the same as in Example 12, the only difference being that the raw materials are not exactly the same, specifically: 16.435g Li2O, 11.841g Mn2O3, 86.937g MnO2, 11.579g Li3PO4, 11.977g Fe2O3, 2.015g MgO, 5.188g LiF, and 7.198g MoO3. 100g of the ball-milled material and 5.263g of carbon black were weighed and mechanically mixed evenly; then placed in a ball mill jar for ball milling reaction (300r / min, 5h), finally obtaining a carbon-coated lithium-rich disordered rock salt polyanionic material. C is completely coated on the material, accounting for approximately 5% of the mass of the cathode material.

[0267] The primary particle size of this lithium-rich rock salt polyanionic material is approximately 150-400 nm. The uniform mixing of carbon black and the lithium-rich material significantly improves the material's conductivity. The XRD diffraction peaks of the material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the diffraction peaks of the material have low intensity and wide peaks, indicating that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0268] Example 28

[0269] This embodiment provides a doped lithium-rich disordered rock salt polyanionic material, the preparation process of which is as follows, with the chemical formula Li.1.8 Mn 1.25 Co 0.1 Mg 0.05 Ti 0.05 Zr 0.05 (PO4) 0.05 O 3.7 F 0.1 @C:

[0270] Raw materials were weighed as follows: 6.6 kg deionized water, 650.44 g LiOH·H2O, 197.35 g Mn2O3, 869.37 g MnO2, 57.90 g Li3PO4, 82.93 g Co2O3, 20.15 g MgO, 39.93 g TiO2, 61.61 g ZrO2, and 25.94 g LiF. These raw materials were sequentially added to the feed tank of a sand mill and milled until the particle size D50 of the slurry was ≤0.4 μm. The slurry was then spray-dried, and the dried powder was sintered at 500 °C for 10 h in an oxygen atmosphere (heating rate controlled at 5 °C / min). 100 g of the sintered product and 1.01 g of carbon nanotubes were mechanically ground and uniformly dispersed in NMP solvent. The dried mixture was then sintered at 200 °C for 5 h in a nitrogen atmosphere to obtain carbon-coated lithium-rich disordered rock salt polyanionic material. The SEM and XRD patterns of the material are shown in Figures 9-10. It can be seen that the primary particle size of the lithium-rich rock salt polyanionic material is approximately 100-150 nm, and the carbon nanotubes are uniformly mixed with the lithium-rich material. The XRD diffraction peaks of the lithium-rich material are consistent with those of lithium-rich spinel lithium manganese oxide (Li). 1.27 Mn 1.73 The standard peaks of O4 match well, indicating that the prepared material maintains the basic structure of the spinel phase. However, the low intensity and wide peaks of the diffraction peaks indicate that the material has transformed from a spinel structure to a disordered rock salt structure. The absence of any other diffraction peaks in XRD indicates that the material has high crystal phase purity and is a single-phase component.

[0271] The above-mentioned positive electrode materials were combined with conductive carbon nanotubes, conductive carbon black, polyvinylidene fluoride (PVDF) binder, and N-methylpyrrolidone (N-Methylpyrrolidone) solvent to form a positive electrode slurry, wherein the mass ratio of the positive electrode material, conductive carbon black, and PVDF binder was 70:20:10. The positive electrode slurry was coated onto aluminum foil, then vacuum baked, stamped, and finally formed into a positive electrode sheet. Using this positive electrode sheet as the positive electrode, a lithium sheet as the negative electrode, and a 1 mol / L LiPF6 DEC / EC / EMC solution as the electrolyte, a button cell battery was assembled. The battery was then subjected to charge-discharge tests (charge-discharge window of 1.5V to 4.8V) to obtain the electrical performance of the lithium-rich disordered rock salt polyanion. The results are shown in Table 2 below. The charge-discharge line (at 10 mA / g current) and cycle curve (at 150 mA / g current) of Example 12 are shown in Figures 7-8, respectively.

[0272] Table 2

[0273] Example 29

[0274] This embodiment provides a composite cathode material, the preparation process of which is as follows: it is LiMn 0.595 Mg 0.005 Fe 0.4 PO4 and Li 1.68 Mn 1.27 Fe 0.1 V 0.05 (PO4) 0.2 O 3.0 F 0.2 @C complex:

[0275] (1) Preparation of LiMn 0.595 Mg 0.005 Fe 0.4 PO4: Add 2.0 kg of deionized water to the feed tank of the sand mill, turn on the sand mill and add 172.35 g of lithium carbonate, 657.77 g of manganese iron phosphate precursor, 56.66 g of glucose monohydrate, 12.59 g of polyethylene glycol, 0.922 g of magnesium oxide and 2.611 g of concentrated phosphoric acid in sequence. Sand mill until the particle size D50 of the slurry is ≤0.5 μm. Set the inlet air temperature of the spray dryer to 240℃ and the outlet air temperature to 110℃. Spray dry the slurry after sand milling into powder. Sinter the powder in a tube furnace under a nitrogen atmosphere. The sintering temperature is 350℃ for 2 hours, and then the temperature is raised to 750℃ and sintered for 10 hours to obtain magnesium-doped manganese iron phosphate with the above molecular formula. Its surface is coated with 2% by mass of carbon.

[0276] (2) Preparation of Li 1.68 Mn 1.27 Fe 0.1 V 0.05 (PO4) 0.2 O 3.0 F 0.2@C: Weigh the following raw materials: 13.195g Li₂O, 39.470g Mn₂O₃, 66.663g MnO₂, 23.159g Li₃PO₄, 7.985g Fe₂O₃, 5.188g LiF, and 4.547g V₂O₅. Place them in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (bead-to-material weight ratio 20:1), seal well, and perform a high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100.0g of the ball-milled material and 1.010g of carbon nanotubes, mix them mechanically until homogeneous, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain the carbon-coated lithium-rich disordered rock salt polyanionic material with the aforementioned molecular formula.

[0277] (3) The magnesium-doped lithium manganese iron phosphate prepared in step (1) and the carbon-coated lithium-rich disordered rock salt polyanionic material prepared in step (2) are stirred in a high-speed mixer at a mass ratio of 9:1 for 15 minutes at a speed of 1200 r / min to obtain the composite cathode material.

[0278] The SEM image of the cathode material is shown in Figure 11. Its XRD pattern is shown in Figure 12. Before composite formation, the primary particle size of lithium manganese iron phosphate was approximately 150-200 nm, while that of the lithium-rich rock salt polyanionic material was approximately 150-400 nm. After composite formation, the average primary particle size was approximately 200 nm. The lithium-rich material and lithium manganese iron phosphate were uniformly composited, exhibiting a synergistic combination at the nano / micro scale, rather than a simple physical mixture. The main XRD diffraction peak of the composite material was consistent with that of lithium manganese iron phosphate. Compared to lithium manganese iron phosphate, the peak of the lithium-rich material was weaker. The main peaks of the lithium-rich material were at 19°, 36°, 44°, and 65°, with no other impurity peaks, indicating that the material is a two-phase composite.

[0279] Example 30

[0280] This embodiment provides a composite cathode material, the preparation process of which is as follows: it is LiMn 0.6 Fe 0.4 PO4 and Li 1.68 Mn 1.27 Fe 0.1 V 0.05 (PO4) 0.2 O 3.0 F 0.2 @C complex:

[0281] (1) Preparation of LiMn 0.6 Fe 0.4PO4: Add 2.0 kg of deionized water to the hopper of the sand mill, turn on the sand mill and add 172.35 g of lithium carbonate, 661.00 g of manganese iron phosphate precursor, 56.66 g of glucose monohydrate and 12.59 g of polyethylene glycol in sequence. Sand mill until the particle size D50 of the slurry is ≤0.5 μm. Set the inlet air temperature of the spray dryer to 240℃ and the outlet air temperature to 110℃. Spray dry the slurry after sand milling into powder. Sinter the powder in a tube furnace under a nitrogen atmosphere. The sintering temperature is 350℃ for 2 hours, and then the temperature is raised to 750℃ and sintered for 10 hours to obtain lithium manganese iron phosphate with the above molecular formula.

[0282] (2) Preparation of Li 1.68 Mn 1.27 Fe 0.1 V 0.05 (PO4) 0.2 O 3.0 F 0.2 @C: Weigh the following raw materials: 13.195g Li₂O, 39.470g Mn₂O₃, 66.663g MnO₂, 23.159g Li₃PO₄, 7.985g Fe₂O₃, 5.188g LiF, and 4.547g V₂O₅. Place them in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (bead-to-material weight ratio 20:1), seal well, and perform a high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100.0g of the ball-milled material and 1.010g of carbon nanotubes, mix them mechanically until homogeneous, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain the carbon-coated lithium-rich disordered rock salt polyanionic material with the aforementioned molecular formula.

[0283] (3) The lithium manganese iron phosphate prepared in step (1) and the carbon-coated lithium-rich disordered rock salt polyanionic material prepared in step (2) are stirred in a high-speed mixer at a speed of 1200 r / min for 15 min at a mass ratio of 9:1 to obtain the composite cathode material.

[0284] Example 31

[0285] This embodiment provides a composite cathode material, the preparation process of which is as follows: it is LiMn 0.595 Mg 0.005 Fe 0.4 PO4 and Li 170 Mn 1.4 (PO4) 0.2 O 3.0 F 0.2 @C complex:

[0286] (1) Preparation of LiMn 0.595Mg 0.005 Fe 0.4 PO4: Add 2.0 kg of deionized water to the feed tank of the sand mill, turn on the sand mill and add 172.35 g of lithium carbonate, 657.77 g of manganese iron phosphate precursor, 56.66 g of glucose monohydrate, 12.59 g of polyethylene glycol, 0.922 g of magnesium oxide and 2.611 g of concentrated phosphoric acid in sequence. Sand mill until the particle size D50 of the slurry is ≤0.5 μm. Set the inlet air temperature of the spray dryer to 240℃ and the outlet air temperature to 110℃. Spray dry the slurry after sand milling into powder. Sinter the powder in a tube furnace under a nitrogen atmosphere. The sintering temperature is 350℃ for 2 hours, and then the temperature is raised to 750℃ and sintered for 10 hours to obtain magnesium-doped manganese iron phosphate with the above molecular formula.

[0287] (2) Preparation of Li 170 Mn 1.4 (PO4) 0.2 O 3.0 F 0.2 @C: Weigh the following raw materials: 13.446g Li₂O, 39.470g Mn₂O₃, 78.243g MnO₂, 23.159g Li₃PO₄, and 5.188g LiF. Place them in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (bead-to-material weight ratio 20:1), seal well, and perform a high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100.0g of the ball-milled material and 1.010g of carbon nanotubes, mix them mechanically until homogeneous, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain the carbon-coated lithium-rich disordered rock salt polyanionic material with the aforementioned molecular formula.

[0288] (3) The magnesium-doped lithium manganese iron phosphate prepared in step (1) and the carbon-coated lithium-rich disordered rock salt polyanionic material prepared in step (2) are stirred in a high-speed mixer at a mass ratio of 9:1 for 15 minutes at a speed of 1200 r / min to obtain the composite cathode material.

[0289] Example 32

[0290] This embodiment provides a composite cathode material, the preparation process of which is as follows: it is LiMn 0.6 Fe 0.4 PO4 and Li 1.70 Mn 1.4 (PO4) 0.2 O 3.0 F 0.2 @C complex:

[0291] (1) Preparation of LiMn 0.6 Fe0.4 PO4: Add 2.0 kg of deionized water to the hopper of the sand mill, turn on the sand mill and add 172.35 g of lithium carbonate, 661.00 g of manganese iron phosphate precursor, 56.66 g of glucose monohydrate and 12.59 g of polyethylene glycol in sequence. Sand mill until the particle size D50 of the slurry is ≤0.5 μm. Set the inlet air temperature of the spray dryer to 240℃ and the outlet air temperature to 110℃. Spray dry the slurry after sand milling into powder. Sinter the powder in a tube furnace under a nitrogen atmosphere. The sintering temperature is 350℃ for 2 hours, and then the temperature is raised to 750℃ and sintered for 10 hours to obtain lithium manganese iron phosphate with the above molecular formula.

[0292] (2) Preparation of Li 1.70 Mn 1.4 (PO4) 0.2 O 3.0 F 0.2 @C: Weigh the following raw materials: 13.446g Li2O, 39.470g Mn2O3, 78.243g MnO2, 23.159g Li3PO4, and 5.188g LiF. Place them in a high-speed mixer and disperse for 5 minutes at 1200 rpm. Then place the mixture in a ball mill jar, add a certain amount of zirconium beads (bead-to-material weight ratio 20:1), seal well, and perform a high-energy ball milling reaction (800 rpm, 10 hours). Weigh 100.0g of the ball-milled material and 1.010g of carbon nanotubes, mix them mechanically until homogeneous, and then place them in a ball mill jar for ball milling reaction (400 rpm, 5 hours). Finally, obtain the carbon-coated lithium-rich disordered rock salt polyanionic material with the aforementioned molecular formula.

[0293] (3) The magnesium-doped lithium manganese iron phosphate prepared in step (1) and the carbon-coated lithium-rich disordered rock salt polyanionic material prepared in step (2) are stirred in a high-speed mixer at a mass ratio of 9:1 for 15 minutes at a speed of 1200 r / min to obtain the composite cathode material.

[0294] Comparative Example 4

[0295] This comparative example provides a carbon-coated lithium-rich disordered rock salt polyanionic material with the molecular formula Li. 1.70 Mn 1.4 (PO4) 0.2 O 3.0 F 0.2@C, the preparation process is as follows: Weigh the raw materials: 13.446g Li2O, 39.470g Mn2O3, 78.243g MnO2, 23.159g Li3PO4 and 5.188g LiF, place them in a high-speed mixer, adjust the speed to 1200 rpm and disperse for 5 min; then place the above mixture in a ball mill jar, add a certain amount of zirconium beads (bead-to-material weight ratio 20:1), seal well, and carry out high-energy ball milling reaction (speed 800 r / min, time 10 h). Weigh 100.0g of the ball-milled material and 1.010g of carbon nanotubes, mix them evenly by mechanical mixing; then place them in a ball mill jar for ball milling reaction (speed 400 r / min, time 5 h), and finally obtain the carbon-coated lithium-rich disordered rock salt polyanionic material with the aforementioned molecular formula.

[0296] Comparative Example 5

[0297] This comparative example provides a comparative lithium iron phosphate cathode material with the molecular formula LiMn. 0.6 Fe 0.4 The preparation process of PO4 is as follows: 2.0 kg of deionized water is added to the hopper of a sand mill. The sand mill is then turned on and 172.35 g of lithium carbonate, 661.00 g of manganese iron phosphate precursor, 56.66 g of glucose monohydrate, and 12.59 g of polyethylene glycol are added sequentially. The sand mill is then milled until the particle size D50 of the slurry is ≤0.5 μm. The spray dryer is set with an inlet air temperature of 240℃ and an outlet air temperature of 110℃. The milled slurry is spray-dried into powder. The powder is sintered in a tube furnace under a nitrogen atmosphere. The sintering temperature is 350℃ for 2 hours, and then the temperature is raised to 750℃ for 10 hours to obtain lithium manganese iron phosphate with the aforementioned molecular formula.

[0298] The above-mentioned positive electrode materials were combined with conductive carbon nanotubes, conductive carbon black, polyvinylidene fluoride (PVDF) binder, and N-methylpyrrolidone (N-Methylpyrrolidone) solvent to form a positive electrode slurry, wherein the mass ratio of the positive electrode material, conductive carbon black, and PVDF binder was 70:20:10. The positive electrode slurry was coated onto aluminum foil, then vacuum baked, stamped, and finally formed into a positive electrode sheet. Using this positive electrode sheet as the positive electrode, lithium foil as the negative electrode, and a 1 mol / L LiPF6 DEC / EC / EMC solution as the electrolyte, a button cell was assembled, and charge-discharge tests were performed on the battery (charge-discharge window 1.5V~4.8V) to obtain the electrical performance of the lithium-rich disordered rock salt polyanion. The results are shown in Table 3 below (discharge specific capacity at 0.03 / 0.1 / 0.5C and capacity retention after 200 cycles at 0.5C). The charge-discharge curves of Example 29 at 0.03C are shown in Figure 13 (LMFP + 10% lithium-rich material), and the cycling curves at 0.5C are shown in Figure 14. The charge-discharge curves of Comparative Example 5 at 0.03C are shown in Figure 13 (LMFP).

[0299] Table 3

[0300] As can be seen, this application combines lithium-rich disordered rock salt polyanionic cathode material with traditional manganese iron phosphate cathode material to obtain a composite cathode material that has both high specific capacity and good cycle stability, thus achieving the complementary advantages of the two materials.

[0301] The disclosure will now be described in conjunction with the various examples and combinations thereof described below.

[0302] 1. A cathode material comprising lithium-rich disordered rock salt polyanions, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanions is Li. 1+a Mn b M h O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0≤h≤1, 0.0001≤f≤1, 0.0001≤g≤1; M is selected from one or more combinations of Cr, Fe, Ni, Co, V, Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si.

[0303] 2. The cathode material according to claim 1, wherein 0.4 ≤ a ≤ 0.8.

[0304] 3. The cathode material according to any one of the preceding claims, characterized in that 1.1 ≤ b ≤ 1.6.

[0305] 4. The cathode material according to any one of the preceding claims, characterized in that 0.1 ≤ f ≤ 0.5.

[0306] 5. The cathode material according to any one of the preceding claims, characterized in that 0.05 ≤ g ≤ 0.3.

[0307] 6. The cathode material according to any one of the preceding claims, characterized in that: the cathode material further comprises carbon coated on the surface of the lithium-rich disordered rock salt polyanion.

[0308] 7. The cathode material according to any one of the preceding claims, characterized in that: the mass percentage of carbon in the cathode material is 0.1%-10%.

[0309] 8. The cathode material according to any one of the preceding claims, characterized in that: the X is selected from P, B or Si, and 0.05 ≤ g ≤ 0.3.

[0310] 9. The cathode material according to any one of the preceding claims, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 Li 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 Li 1.77 Mn 1.33 (PO4) 0.2 O 2.8 F 0.4 Li 1.53 Mn 1.57 (PO4) 0.1 O 3.4 F 0.2 Li 1.78 Mn 1.32 (PO4) 0.25 O 2.8 F 0.2 Li 1.45 Mn 1.65 (PO4) 0.05 O 3.6 F 0.2 Li 1.70 Mn 1.31 (PO4) 0.2 O 2.65 F 0.55 Li 1.70 Mn 1.24 (PO4) 0.35 O 2.5 F 0.1 .

[0311] 10. The cathode material according to any one of the preceding claims, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M1 c M2 d M3 e O 4-f-4g F f (XO4) gWherein, 0.1≤a≤2, 1≤b≤2, 0≤c≤1, 0≤d≤1, 0≤e≤1, 0<c+d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M1 is selected from one or more combinations of Cr, Fe, Ni, Co, and V; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; and X is selected from one or more combinations of N, P, B, S, and Si.

[0312] 11. The cathode material according to any one of the preceding claims, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M2 d M3 e O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0<d≤1, 0<e≤1, 0<d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si.

[0313] 12. The cathode material according to any one of the preceding claims, characterized in that 0.001 ≤ d ≤ 0.1.

[0314] 13. The cathode material according to any one of the preceding claims, characterized in that 0.001 ≤ e ≤ 0.3.

[0315] 14. The cathode material according to any one of the preceding claims, characterized in that 0.05 ≤ d + e ≤ 0.3.

[0316] 15. The cathode material according to any one of the preceding claims, characterized in that M2 is Mg and M3 is Mo or Nb.

[0317] 16. The cathode material according to any one of the preceding claims, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M1 c O 4-f-4g F f (XO4) gWherein, 0.1≤a≤2, 1≤b≤2, 0<c≤1, 0.0001≤f≤1, 0.0001≤g≤1; M1 is selected from one or more combinations of Cr, Fe, Ni, Co, and V; X is selected from one or more combinations of N, P, B, S, and Si.

[0318] 17. The cathode material according to any one of the preceding claims, characterized in that M1 is a combination of V and at least one selected from Cr, Fe, Ni, and Co.

[0319] 18. The cathode material according to any one of the preceding claims, wherein M1 is a combination of Co and V, or a combination of Fe and V, or a combination of Ni and V.

[0320] 19. The cathode material according to any one of the preceding claims, characterized in that 0.05 ≤ c ≤ 0.5.

[0321] 20. The cathode material according to any one of the preceding claims, characterized in that 0.0001 ≤ h ≤ 1.

[0322] 21. The cathode material according to any one of the preceding claims, characterized in that 0.05 ≤ h ≤ 0.3.

[0323] 22. The cathode material according to any one of the preceding claims, characterized in that the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1.66 Mn 1.28 Mg 0.1 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.70 Mn 1.30 Mg 0.05 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.60 Mn 1.25 Mg 0.2 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.65 Mn 1.30 Mg 0.1 Nb 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.60 Mn 1.30 Mg0.1 Al 0.1 (PO4) 0.2 O 3.0 F 0.2 Li 1.71 Mn 1.36 Mg 0.01 Mo 0.02 (PO4)0.2O3.0F0.2, Li 1.77 Mn 0.83 Mg 0.3 Mo 0.1 (PO4)0.2O3.0F0.2, Li 1.72 Mn 1.24 Co 0.05 V 0.1 (PO4)0.2O3.0F0.2, Li 1.70 Mn 1.30 Co 0.05 V 0.05 (PO4)0.2O3.0F0.2, Li 1.73 Mn 1.17 Co 0.05 V 0.15 (PO4)0.2O3.0F0.2, Li 1.72 Mn 1.24 Fe 0.05 V 0.10 (PO4)0.2O3.0F0.2, Li 1.73 Mn 1.17 Ni 0.05 V 0.10 (PO4)0.2O3.0F0.2, Li 1.6 Mn 1.15 Fe 0.15 Mg 0.05 Mo 0.05 (PO4) 0.1 O 3.4 F 0.2 Or Li 1.8 Mn 1.25 Co 0.1 Mg 0.05 Ti 0.05 Zr 0.05 (PO4) 0.05 O 3.7 F 0.1 .

[0324] The above embodiments are only for illustrating the technical concept and features of this disclosure, and are intended to enable those skilled in the art to understand the content of this disclosure and implement it accordingly. They should not be construed as limiting the scope of protection of this disclosure. All equivalent changes or modifications made in accordance with the spirit and essence of this disclosure should be included within the scope of protection of this disclosure.

[0325] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A cathode material comprising lithium-rich disordered rock salt polyanions, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M h O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0≤h≤1, 0.0001≤f≤1, 0.0001≤g≤1; M is selected from one or more combinations of Cr, Fe, Ni, Co, V, Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si.

2. The cathode material according to claim 1, characterized in that, 0.4≤a≤0.8; and / or, 1.1≤b≤1.6; and / or, 0.1≤f≤0.5; and / or, 0.05≤g≤0.

3.

3. The cathode material according to claim 1 or 2, characterized in that: The cathode material further includes carbon coated on the surface of the lithium-rich disordered rock salt polyanion; preferably, the mass percentage of the carbon in the cathode material is 0.1%-10%; and / or, the X is selected from P, B or Si, 0.05≤g≤0.

3.

4. The cathode material according to claim 1 or 2, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 Li 1.66 Mn 1.43 (PO4) 0.2 O 3.1 F 0.1 Li 1.77 Mn 1.33 (PO4) 0.2 O 2.8 F 0.4 Li 1.53 Mn 1.57 (PO4) 0.1 O 3.4 F 0.2 Li 1.78 Mn 1.32 (PO4) 0.25 O 2.8 F 0.2 Li 1.45 Mn 1.65 (PO4) 0.05 O 3.6 F 0.2 Li 1.70 Mn 1.31 (PO4) 0.2 O 2.65 F 0.55 Li 1.70 Mn 1.24 (PO4) 0.35 O 2.5 F 0.1 .

5. The cathode material according to claim 1, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M1 c M2 d M3 e O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0≤c≤1, 0≤d≤1, 0≤e≤1, 0<c+d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M1 is selected from one or more combinations of Cr, Fe, Ni, Co, and V; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; and X is selected from one or more combinations of N, P, B, S, and Si.

6. The cathode material according to claim 5, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M2 d M3 e O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0<d≤1, 0<e≤1, 0<d+e≤1, 0.0001≤f≤1, 0.0001≤g≤1; M2 is selected from one or more combinations of Mg, Zn, Cu, and Al; M3 is selected from one or more combinations of Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, and Si; X is selected from one or more combinations of N, P, B, S, and Si.

7. The cathode material according to claim 5, characterized in that: 0.001≤d≤0.1; and / or, 0.001≤e≤0.3; preferably, 0.05≤d+e≤0.3; and / or, M2 is Mg, and M3 is Mo or Nb.

8. The positive electrode material according to claim 5, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1+a Mn b M1 c O 4-f-4g F f (XO4) g Wherein, 0.1≤a≤2, 1≤b≤2, 0<c≤1, 0.0001≤f≤1, 0.0001≤g≤1; M1 is selected from one or more combinations of Cr, Fe, Ni, Co, and V; X is selected from one or more combinations of N, P, B, S, and Si.

9. The cathode material according to claim 8, characterized in that, M1 is a combination of V and at least one selected from Cr, Fe, Ni, and Co.

10. The cathode material according to claim 8, characterized in that, M1 is a combination of Co and V, or a combination of Fe and V, or a combination of Ni and V; and / or, 0.05 ≤ c ≤ 0.

5.

11. The cathode material according to claim 1, characterized in that: 0.0001≤h≤1; preferably, 0.05≤h≤0.

3.

12. The cathode material according to claim 1, characterized in that, The molecular formula of the lithium-rich disordered rock salt polyanion is Li 1.66 Mn 1.28 Mg 0.1 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.70 Mn 1.30 Mg 0.05 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.60 Mn 1.25 Mg 0.2 Mo 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.65 Mn 1.30 Mg 0.1 Nb 0.05 (PO4) 0.2 O 3.0 F 0.2 Li 1.60 Mn 1.30 Mg 0.1 Al 0.1 (PO4) 0.2 O 3.0 F 0.2 Li 1.71 Mn 1.36 Mg 0.01 Mo 0.02 (PO4)0.2O3.0F0.2, Li 1.77 Mn 0.83 Mg 0.3 Mo 0.1 (PO4)0.2O3.0F0.2, Li 1.72 Mn 1.24 Co 0.05 V 0.1 (PO4)0.2O3.0F0.2, Li 1.70 Mn 1.30 Co 0.05 V 0.05 (PO4)0.2O3.0F0.2, Li 1.73 Mn 1.17 Co 0.05 V 0.15 (PO4)0.2O3.0F0.2, Li 1.72 Mn 1.24 Fe 0.05 V 0.10 (PO4)0.2O3.0F0.2,Li 1.73 Mn 1.17 Ni 0.05 V 0.10 (PO4)0.2O3.0F0.2,Li 1.6 Mn 1.15 Fe 0.15 Mg 0.05 Mo 0.05 (PO4) 0.1 The 3.4 F 0.2 Or Li 1.8 Mn 1.25 Co 0.1 Mg 0.05 Ti 0.05 Zr 0.05 (PO4) 0.05 The 3.7 F 0.1 。 13. A method for preparing the cathode material according to any one of claims 1-12, characterized in that, The preparation method includes the following steps: 1) mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, an optional compound containing element M, and optional water to obtain a mixture; 2) ball milling or grinding and sintering the mixture to obtain the lithium-rich disordered rock salt polyanion. 3) The lithium-rich disordered rock salt polyanion and carbon source are mixed and subjected to secondary ball milling or secondary grinding and sintering to obtain the cathode material.

14. The method for preparing the cathode material according to claim 13, characterized in that: The preparation method includes the following steps: 1) mechanically mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, and optionally a compound containing element M to obtain a mixture; 2) ball milling and reacting the mixture in a ball mill jar to obtain the lithium-rich disordered rock salt polyanion. 3) The lithium-rich disordered rock salt polyanion and carbon source are mechanically mixed, and then ball-milled and reacted in a ball mill jar to obtain the cathode material.

15. The method for preparing the cathode material according to claim 14, characterized in that: In step 1), the rotational speed of the mechanical mixing is 1000-2000 rpm; and / or, the mechanical mixing time is 1-10 min.

16. The method for preparing the cathode material according to claim 14, characterized in that: In step 2), the ball milling is performed using grinding balls; preferably, the grinding balls are made of one or more of zirconium beads, agate beads, and stainless steel beads; and / or, the mass ratio of the grinding balls to the mixture is 5-30:1; and / or, the ball milling time is 1-20 hours; and / or, the ball milling speed is 400-2000 rpm.

17. The method for preparing the cathode material according to claim 14, characterized in that: In step 3), the rotation speed of the secondary ball mill is 200-500 rpm; and / or, the time of the secondary ball mill is 0.5-10 h.

18. The method for preparing the cathode material according to claim 13, characterized in that: The preparation method includes the following steps: 1) mechanically mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, water, and optionally a compound containing element M to obtain a mixture; 2) grinding the mixture to obtain a slurry with a D50 particle size less than or equal to 0.4 μm, spray-drying the slurry to obtain a powder, and sintering the powder in an oxygen atmosphere to obtain the lithium-rich disordered rock salt polyanion; 3) dispersing the lithium-rich disordered rock salt polyanion and a carbon source in an organic solvent by grinding, drying, and then performing solid-phase sintering to obtain the cathode material.

19. The method for preparing the cathode material according to claim 18, characterized in that: In step 2), the grinding is carried out in a sand mill; and / or, in step 2), the sintering temperature is 300-700℃; and / or, in step 2), the sintering time is 1-30h.

20. The method for preparing the cathode material according to claim 18, characterized in that: The organic solvent is selected from one or more combinations of N-methylpyrrolidone, isopropanol, acetone, ethyl acetate, dimethylacetamide, and dimethylformamide; and / or, the solid-phase sintering is carried out in a nitrogen atmosphere; and / or, in step 3), the solid-phase sintering temperature is 100-300℃; and / or, in step 3), the solid-phase sintering time is 1-10h.

21. The method for preparing the cathode material according to claim 13, characterized in that: The lithium source is selected from one or more combinations of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium hydride, lithium nitride, lithium peroxide, lithium chloride, lithium nitrate, lithium sulfate, lithium phosphate, lithium monohydrogen phosphate, lithium dihydrogen phosphate, lithium citrate, lithium lauryl phosphate, and lithium ascorbate; and / or, the manganese source is selected from one or more combinations of manganese dioxide, manganese tetroxide, manganese trioxide, manganese monoxide, manganese hydroxide, manganese carbonate, manganese sulfate, manganese nitrate, manganese acetate, manganese chloride, potassium permanganate, manganese dihydrogen phosphate, manganese oxalate, manganese phosphate, manganese pyrophosphate, and manganese ferrophosphate; and / or, the fluorine source is selected from lithium fluoride, manganese fluoride, magnesium fluoride, sodium fluoride, potassium fluoride, hydrofluoric acid, Freon, and hexafluoride. One or more combinations of fluorophosphoric acid; and / or, when X is N, the compound containing element X is a nitrogen source, the nitrogen source being selected from one or more combinations of ammonium nitrate, lithium nitrate, magnesium nitrate, ferric nitrate, manganese nitrate, guanidine nitrate, cobalt nitrate, aluminum nitrate, copper nitrate, and nickel nitrate; when X is P, the compound containing element X is a phosphorus source, the phosphorus source being selected from one or more combinations of phosphorus pentoxide, phosphoric acid, pyrophosphate, lithium phosphate, lithium monohydrogen phosphate, lithium dihydrogen phosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, manganese dihydrogen phosphate, sodium phosphate, potassium phosphate, ferric phosphate, manganese phosphate, manganese pyrophosphate, and manganese iron phosphate; when X is B, the compound containing element X is boron. The boron source is selected from one or more combinations of boron oxide, boric acid, boron nitride, boron sulfide, silicon boride, vanadium boride, titanium boride, tungsten boride, molybdenum boride, iron boride, niobium boride, chromium boride, magnesium boride, boron phosphate, lithium borate, ammonium fluoroborate, sodium borate, potassium borate, and borate esters. When X is S, the compound containing element X is a sulfur source, and the sulfur source is selected from one or more combinations of sulfuric acid, sulfurous acid, ammonium sulfate, potassium sulfate, sodium sulfate, thiourea, thiols, thioethers, sodium sulfide, boron sulfide, potassium sulfide, iron sulfide, lithium sulfide, magnesium sulfide, manganese sulfide, nickel sulfide, tin sulfide, tungsten sulfide, niobium sulfide, thioacetic acid, potassium thiocyanate, cobalt sulfide, tantalum sulfide, vanadium sulfide, and chromium sulfide. When X is Si, the boron source is selected from one or more combinations of boron oxide, boronic acid, boron nitride, boron sulfide, vanadium sulfide, and boron sulfide. The compound containing element X is a silicon source, and the silicon source is selected from one or more combinations of silicon oxide, silicic acid, silica gel, potassium silicate, silane, silicon nitride, vanadium silicide, tungsten silicide, titanium silicide, cobalt silicide, cobalt silicide, tantalum silicide, iron silicide, manganese silicide, niobium silicide, nickel silicide, diatomaceous earth, lithium silicate, silicon sulfide, silicon boride, silicon carbide, molybdenum silicon powder, and silicone oil; and / or, the carbon source is selected from one or more combinations of activated carbon, carbon black, carbon nanotubes, graphite, graphene, and graphene oxide; and / or, the compound containing element M is selected from one or more combinations of oxides, fluorides, carbonates, oxalates, nitrates, sulfates, chlorides, and organic acid salts of element M.

22. A cathode material composite, characterized in that, The composite comprises the cathode material according to any one of claims 1-12 and lithium manganese iron phosphate; the molecular formula of the lithium manganese iron phosphate is LiMn. 1-x-y Fe x M' y PO4, wherein M' is one or more of Mg, Ti, V, Cr, Co, Ni, Zn, Ga, Al, Zr, Nb, Mo, Sn, Sb, Ca, Ba, Si, B, Ru, Si, Te, and Cu, and 0.01≤x≤0.98, 0≤y≤0.

1.

23. The cathode material composite according to claim 22, characterized in that, The mass ratio of the lithium-rich disordered rock salt polyanion and lithium manganese iron phosphate is 1-5:5-9; preferably 1-2:8-9.

24. The cathode material composite according to claim 22, characterized in that, The surface of the lithium-rich disordered rock salt polyanion is coated with carbon; and / or, the surface of the lithium manganese iron phosphate is coated with carbon.

25. The cathode material composite according to claim 24, characterized in that: The surface of the lithium-rich disordered rock salt polyanion is coated with carbon at a mass percentage of 0.1%-10%; and / or, the surface of the lithium manganese iron phosphate is coated with carbon at a mass percentage of 0.1%-10%.

26. The cathode material composite according to claim 22, characterized in that: The M is selected from one or more combinations of Cr, Fe, Ni, Co, and V; preferably, the M is selected from one or two of Fe and V; and / or, 0.001≤h≤0.3; preferably, 0.05≤h≤0.

3.

27. The cathode material composite according to claim 22, characterized in that: h = 0; or, M is Fe and V, and 0.05 ≤ h ≤ 0.

3.

28. The cathode material composite according to claim 22, characterized in that: M' is one or more selected from Mg, Ca, Ba, and Si; and / or, 10 -4 ≤y≤0.1; preferably 0.01≤y≤0.

1.

29. The cathode material composite according to claim 22, characterized in that: y = 0, or M' is one or more combinations selected from Mg, Ca, Ba, Si, and 0.01 ≤ y ≤ 0.

1.

30. A lithium-ion battery, characterized in that: The lithium-ion battery includes the cathode material according to any one of claims 1-12 or the cathode material composite according to any one of claims 22-29.

31. The lithium-ion battery according to claim 30, characterized in that: The lithium-ion battery has a discharge specific capacity of 200-350 mAh / g at a current of 10 mA / g, a discharge specific capacity of 150-300 mAh / g or more at a current of 100 mA / g, and a capacity retention rate of 60%-90% after 200 charge-discharge cycles at a current of 150 mA / g.

32. The lithium-ion battery according to claim 30, characterized in that: The lithium-ion battery has a discharge specific capacity of 220-270 mAh / g at a current of 10 mA / g, a discharge specific capacity of 150-200 mAh / g or more at a current of 100 mA / g, and a capacity retention rate of 60%-72% after 200 charge-discharge cycles at a current of 150 mA / g.

33. The lithium-ion battery according to claim 30, characterized in that: The lithium-ion battery has a discharge specific capacity of 240-310 mAh / g at a current of 10 mA / g, a discharge specific capacity of 180-260 mAh / g or more at a current of 100 mA / g, and a capacity retention rate of 68%-80% after 200 charge-discharge cycles at a current of 150 mA / g.

34. The lithium-ion battery according to claim 30, characterized in that: The lithium-ion battery has a discharge specific capacity of 160-180 mAh / g at a current of 10 mA / g, a discharge specific capacity of 160-180 mAh / g at a current of 30 mA / g, a discharge specific capacity of 140-170 mAh / g at a current of 30 mA / g, and a capacity retention rate of 90%-99% after 200 charge-discharge cycles at a current of 150 mA / g.

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