A cation-doped lithium-rich disordered rock-salt polyanion cathode material, and a preparation method and use thereof

Abstract

This invention discloses a cation-doped lithium-rich disordered rock salt polyanion cathode material, its preparation method, and its applications. The cathode material comprises lithium-rich disordered rock salt polyanions and carbon coated on their surface, wherein 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. This invention, by doping with specific metal cations, can improve its cycling stability, especially its cycling performance under high pressure, while ensuring high capacity.

Description

Technical Field

[0001] This invention relates to a cation-doped lithium-rich disordered rock salt polyanionic cathode material, its preparation method, and its applications. Background Technology

[0002] The performance of cathode materials directly affects the energy density, cycle stability, and safety of lithium-ion batteries. Lithium-rich disordered rock salt polyanionic cathode materials (DRX) have attracted much attention due to their high specific capacity and excellent voltage platform, but there are still many performance issues that need to be improved in practical applications.

[0003] Lithium-rich disordered rock salt polyanionic cathode materials possess a unique three-dimensional disordered cation framework structure. This structure can stabilize the oxygen lattice and oxygen valence change reactions in lithium-rich oxide cathode materials, thereby improving lithium-ion migration and enhancing the material's cycle performance. However, this material exhibits poor cycle stability at high voltages, especially above 4.8V, where it is prone to oxygen release and structural collapse, leading to rapid capacity decay.

[0004] Improving the cycling performance of lithium-rich disordered rock salt polyanion cathode materials under high voltage is a key challenge. Summary of the Invention

[0005] In view of the shortcomings and deficiencies of the prior art, the present invention provides an improved lithium-rich disordered rock salt polyanionic cathode material, which can improve its cycle stability, especially its cycle performance under high voltage, while ensuring high capacity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A cathode material comprising lithium-rich disordered rock salt polyanions, the cathode material further comprising carbon coated on the surface of the lithium-rich disordered rock salt polyanions, wherein 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.

[0008] In this invention, "lithium-rich" refers to a material with a relatively high lithium content. Typically, the lithium content in lithium-rich materials exceeds the conventional stoichiometry, and excess lithium helps improve the electrochemical performance of the material. Disordered rock salt structure refers to an atomic arrangement in a material with a face-centered cubic oxygen sublattice. In disordered rock salt structures, the distribution of transition metal ions and lithium ions in the lattice lacks significant long-range order, unlike in some ordered structures where atoms are arranged in a specific, orderly manner. This disorder significantly impacts the material's performance; for example, cathode materials with disordered rock salt structures rely on the redox reaction of oxygen ions to achieve high capacity under high voltage, but this can also lead to factors such as gas generation, causing structural instability. Polyanions refer to negatively charged ionic groups formed by multiple atoms bonded together by covalent bonds, such as phosphate, borate, silicate, and sulfate. In lithium-rich disordered rock salt polyanionic materials, the introduction of polyanionic groups is to enhance the material's stability. The central atom in polyanions (such as B, P, Si, S, N, etc.) forms a strong covalent bond with oxygen atoms. When they enter the rock salt structure, they can make the oxygen ions near the central atom more stable, significantly reducing the risk of oxygen release, thereby enhancing the structural stability and cycle life of the material.

[0009] Furthermore, this invention applies cation doping technology to improve the performance of lithium-rich disordered rock salt polyanionic cathode materials.

[0010] 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) 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; X is selected from one or more combinations of N, P, B, S, and Si. At least one of the three types of doped cations M1, M2, and M3 is used for doping.

[0011] In some embodiments, the molecular formula of the lithium-rich disordered rock salt polyanion is Li. 1+a Mn b M2 d M3e 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. This cathode material is doped with two types of metallic elements, M2 and M3, neither of which possesses electrochemical activity but can improve the performance of the cathode material, such as its electrochemical performance under high temperature and high pressure.

[0012] In this scheme, cation doping introduces electrochemically inactive metal ions (such as Mg, Zn, Al, Nb, etc.) to adjust the lattice parameters and electronic structure of the material, suppressing unfavorable phase transitions and interfacial side reactions, thereby enhancing the structural stability and electrochemical performance of the material. For example, Al doping can improve the crystal phase stability of the material, while Mg doping helps to improve the cycle life and rate performance of the material, and Nb can provide charge compensation, increasing the number of lithium ions that can be inserted and extracted; during the lithium insertion and extraction process, it can play a structural supporting role. The optimized selection of doping element types and doping ratios in this invention can achieve lithium-rich disordered rock salt polyanionic cathode materials with longer cycle life and better safety. In some embodiments, 0.001 ≤ d ≤ 0.1.

[0013] In some implementations, 0.001 ≤ e ≤ 0.3.

[0014] In some implementations, 0.05 ≤ d + e ≤ 0.3. By controlling the total amount of the two types of doped metal ions within this range, the electrical performance of the cathode material can be further optimized.

[0015] In some implementations, M2 is Mg and M3 is Mo or Nb. This combination of metals in M2 and M3 can achieve better electrical performance.

[0016] In some embodiments, 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.

[0017] In this scheme, cation doping introduces electrochemically active metal ions (such as Cr, Fe, Ni, Co, V, etc.) to promote charge transfer and catalyze redox reactions. The electroactive metal cations act as "intermediaries" for electron transfer, significantly accelerating the redox kinetics of anions (oxygen) and improving the material's specific capacity. Due to their strong binding ability with oxygen, they can effectively catalyze anion activity, enabling multi-electron reactions and improving overall electrochemical performance. Furthermore, by occupying transition metal sites, they effectively inhibit the migration of transition metal ions to the lithium layer, improving the material's structural stability and slowing down the formation of spinel phases during cycling, thus improving cycle life and capacity retention.

[0018] In some embodiments, M1 is a combination of V and at least one selected from Cr, Fe, Ni, and Co.

[0019] In some embodiments, M1 is a combination of Co and V, or a combination of Fe and V, or a combination of Ni and V.

[0020] In some implementations, 0.05 ≤ c ≤ 0.5.

[0021] In some implementations, 0.4 ≤ a ≤ 0.8.

[0022] In some implementations, 1.1 ≤ b ≤ 1.6.

[0023] 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.

[0024] 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.

[0025] In some implementations, 0.0001 ≤ h ≤ 1. The metal element doped in the cathode material can be one or more of the optional types listed for element M.

[0026] In some implementations, 0.05 ≤ h ≤ 0.3. By controlling the amount of doped metal ions within this range, the electrical performance of the cathode material can be further optimized.

[0027] In some embodiments, M is selected from two or more combinations of Mg, Zn, Cu, and Al. This specific combination of M elements can achieve better electrical performance.

[0028] In some embodiments, the carbon content accounts for 0.1%-10% of the mass of the cathode material. 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 the active material, lowers the cathode material's capacity, and an overly thick carbon coating hinders lithium-ion transport, reduces lithium-ion diffusion efficiency, and affects rate performance.

[0029] In some embodiments, X is selected from P, B, or Si. Preferably, X is P.

[0030] In some embodiments, X is selected from P, B or Si, and 0.05 ≤ g ≤ 0.3.

[0031] In some embodiments, 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 Mg0.01 Mo 0.02 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.77 Mn 0.83 Mg 0.3 Mo 0.1 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.72 Mn 1.24 Co 0.05 V 0.1 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.70 Mn 1.30 Co 0.05 V 0.05 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.73 Mn 1.17 Co 0.05 V 0.15 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.72 Mn 1.24 Fe 0.05 V 0.10 (PO4) 0.2 The 3.0 F 0.2 ,Li 1.73 Mn 1.17 Ni 0.05 V 0.10 (PO4) 0.2 The 3.0 F 0.2 ,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 1.2 5Co 0.1 Mg 0.05 Ti 0.05 Zr 0.05 (PO4) 0.05 The 3.7 F 0.1 。

[0032] The present invention also provides a method for preparing the aforementioned cathode material, the method comprising the following steps: 1) mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, a compound containing element M, and optionally water to obtain a mixture; 2) ball milling or grinding and sintering the mixture to obtain the lithium-rich disordered rock salt polyanion; 3) mixing the lithium-rich disordered rock salt polyanion with a carbon source, and performing secondary ball milling or secondary grinding and sintering to obtain the cathode material.

[0033] 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 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 and a carbon source, and then ball milling and reacting again 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 ball milling process to generate lithium-rich disordered rock salt polyanion. This polyanion is then ball-milled with a carbon source and undergoes a coating reaction, allowing carbon to be coated onto the surface of the lithium-rich disordered rock salt polyanion. This process eliminates the need for solvents, drying, and long sintering steps. Mechanical force can achieve uniform mixing of the precursor, while simultaneously refining powder particles and improving the microstructure of the material. Furthermore, the local pressure effect can promote the diffusion and uniform distribution of lithium ions, thereby improving the electrochemical performance of the material. The secondary ball milling and carbon coating further enhances the rate capability and cycle performance of the material.

[0034] In some implementations, in step 1), the rotational speed of the mechanical mixing is 1000-2000 rpm.

[0035] In some embodiments, the mechanical mixing time is 1-10 minutes.

[0036] 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.

[0037] In some embodiments, the grinding beads are made of one or more of zirconium beads, agate beads, and stainless steel beads.

[0038] In some embodiments, the ball milling time is 1-20 hours.

[0039] In some embodiments, the ball mill rotates at a speed of 400-2000 rpm.

[0040] In some implementations, in step 3), the rotational speed of the secondary ball mill is 200-500 rpm.

[0041] In some embodiments, the secondary ball milling time is 0.5-10 hours.

[0042] 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, a compound containing element M, and water 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 under 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-state sintering to obtain the cathode material. This method uses a slurry and spray method, which is more conducive to industrialization.

[0043] In some implementations, step 2) involves grinding in a sand mill.

[0044] In some embodiments, the sintering temperature in step 2) is 300-700°C.

[0045] In some implementations, the sintering time in step 2) is 1-30 hours.

[0046] 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).

[0047] In some embodiments, the solid-phase sintering is carried out in a nitrogen atmosphere.

[0048] In some embodiments, in step 3), the solid-state sintering temperature is 100-300°C.

[0049] In some embodiments, in step 3), the solid-state sintering time is 1-10 hours.

[0050] 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.

[0051] 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, and manganese pyrophosphate.

[0052] In some embodiments, the manganese source is a mixture of manganese trioxide and manganese dioxide.

[0053] 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.

[0054] 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, and manganese pyrophosphate. 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 lithium borate. The compound containing element X is selected from one or more combinations of ammonium fluoroborate, sodium borate, potassium borate, and borate esters. When X is S, the compound containing element X is a sulfur source. 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. 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.

[0055] 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.

[0056] The amount of each raw material fed is determined based on the molecular formula of the final target cathode material.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The ruthenium source is selected from ruthenium oxide, ruthenium acetate, ruthenium chloride, etc.

[0068] The tantalum source is selected from tantalum oxide, tantalum phosphide, tantalum fluoride, tantalum nitride, tantalum carbide, lithium tantalate, tantalum chloride, tantalum sulfide, etc.

[0069] 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.

[0070] The tin source is selected from tin oxide, tin fluoride, tin acetate, sodium stannate, potassium stannate, stannous sulfate, tin chloride, tin oxalate, etc.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The present invention also provides a lithium-ion battery, including a positive electrode material, wherein the positive electrode material includes the aforementioned positive electrode material.

[0076] 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.

[0077] Furthermore, 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.

[0078] Compared with the prior art, the present invention has the following advantages:

[0079] The lithium-rich disordered rock salt polyanionic cathode material of the present invention can improve its cycle stability, especially its cycle performance under high voltage, while ensuring high capacity. Attached Figure Description

[0080] Figure 1 This is a schematic diagram of the preparation process in Example 1;

[0081] Figure 2 The two images are SEM images of the cathode material prepared in Example 1, with different scales.

[0082] Figure 3 The image shows the XRD pattern of the cathode material prepared in Example 1.

[0083] Figure 4 The charge-discharge curves of the cathode material prepared in Example 1 at a current of 10 mA / g are shown.

[0084] Figure 5 The cycling curve of the cathode material prepared in Example 1 at a current of 150 mA / g is shown.

[0085] Figure 6 This is a schematic diagram of the preparation process in Example 17;

[0086] Figure 7 The two images are SEM images of the cathode material prepared in Example 17, with different scales.

[0087] Figure 8 The image shows the XRD pattern of the cathode material prepared in Example 17. Detailed Implementation

[0088] 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 the lack of cycle stability and oxygen release problems.

[0089] This invention provides an improved lithium-rich disordered rock salt polyanionic cathode material. One of its innovations is the combination of lithium-rich disordered rock salt material (high capacity) and polyanionic material (high stability), with fluorine doping of oxygen and carbon coating on the lithium-rich disordered rock salt polyanionic 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.

[0090] 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.

[0091] Another innovation of this invention, regarding the introduction of non-electrochemically active metal ions for doping, lies in doping the lithium-rich disordered rock salt polyanionic cathode material with M metal element ions. M can be selected from Mg, Zn, Cu, Al, Nb, Ti, Mo, Ru, W, Ta, Sn, Zr, Ru, Sb, Te, Re, Si, etc. This M element cannot change its valence and is a high-valence metal ion. While it lacks electrochemical activity, it can improve charge compensation and increase the number of lithium ions that can be inserted or extracted. During the lithium insertion / extraction process, this doped high-valence metal ion can provide structural support, improving the material's stability. In other words, this invention, 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.

[0092] 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.

[0093] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0094] Example 1

[0095] 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:

[0096] 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.

[0097] 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.

[0098] Example 2

[0099] 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 The preparation process of @C is basically the same as in Example 1, except that the raw materials are not exactly the same. Specifically, the raw materials are: 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 1, 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.

[0100] 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.

[0101] Example 3

[0102] 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 1, except that the raw materials are not exactly the same. Specifically, they 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 1, resulting in a carbon-coated lithium-rich disordered rock salt polyanionic material. The C coating accounts for approximately 1% of the mass of the cathode material.

[0103] 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.

[0104] Example 4

[0105] 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 1, 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.

[0106] 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.

[0107] 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.

[0108] Example 5

[0109] 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 1, 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.

[0110] 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.

[0111] 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.

[0112] Example 6

[0113] 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:

[0114] 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.

[0115] 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.

[0116] Example 7

[0117] 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 6, the only difference being that the raw materials are not exactly the same, specifically:

[0118] 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 6, 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.

[0119] 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.

[0120] Example 8

[0121] 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 0.2The preparation process of @C is basically the same as in Example 6, except that the raw materials are not exactly the same. Specifically, the raw materials are: 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, and finally, the target carbon-coated lithium-rich disordered rock salt polyanionic material is obtained. The C coating on the material accounts for approximately 1% of the mass percentage of the cathode material.

[0122] 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.

[0123] Example 9

[0124] 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 1, the only difference being that the raw materials are not exactly the same, specifically:

[0125] 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 1, 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.

[0126] 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.

[0127] Example 10

[0128] 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 1, 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 1, 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.

[0129] 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.

[0130] Example 11

[0131] 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 1, except that the raw materials are not exactly the same. Specifically, they 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.

[0132] Example 12

[0133] 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 1, 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 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.

[0134] Example 13

[0135] 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 1, 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 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.

[0136] Example 14

[0137] 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 1, except that the raw materials are not exactly the same. Specifically, the raw materials 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 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.

[0138] Example 15

[0139] 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 1, except that the raw materials are not exactly the same. Specifically, the raw materials 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 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.

[0140] Example 16

[0141] 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 The preparation process of @C is basically the same as in Example 1, except that the raw materials are not exactly the same. Specifically, they are: 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 are weighed and mechanically mixed evenly; then the mixture is placed in a ball mill jar for ball milling reaction (300 r / min, 5 h), finally yielding 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.

[0142] 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.

[0143] Example 17:

[0144] 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:

[0145] 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 a carbon-coated lithium-rich disordered rock salt polyanionic material. The preparation process diagram is as follows: Figure 6 As shown.

[0146] The SEM and XRD images of the material are as follows: Figure 7-8 As shown, 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 similar to 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.

[0147] Comparative Example 1

[0148] This comparative example provides a lithium-rich disordered rock salt polyanionic material that is not doped with M metal ions. The specific preparation method is as follows, and the chemical formula is Li. 1.70 Mn 1.40 (PO4) 0.2 O 3.0 F 0.2 @C:

[0149] 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.

[0150] 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, punched, 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 battery 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 1 below. The charge-discharge line (at 10 mA / g current) and cycle curve (at 150 mA / g current) of Example 1 are shown in Table 1 below. Figure 4-5 As shown.

[0151] Table 1

[0152]

[0153]

[0154] It is evident that the doped lithium-rich disordered rock salt polyanionic material of this application has high discharge specific capacity and cycle performance, and exhibits superior electrical performance compared to the undoped lithium-rich disordered rock salt polyanionic material.

[0155] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0156] 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 positive electrode material comprising a lithium-rich disordered rock-salt polyanion, characterized in that, The cathode material further includes 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 Where 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 positive electrode material of claim 1, wherein, 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.

3. The positive electrode material according to claim 2, 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.

4. The positive electrode material of claim 3, wherein: 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.

5. The cathode material of claim 2, wherein, 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.

6. The positive electrode material according to claim 5, characterized in that, M1 is a combination of V and at least one selected from Cr, Fe, Ni, and Co.

7. The cathode material of claim 5, wherein, 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.

8. The positive electrode material of claim 1 or 2, 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.

9. The cathode material of claim 1, wherein: 0.0001≤h≤1; preferably, 0.05≤h≤0.

3.

10. The positive electrode material of claim 1 or 2, wherein: The mass percentage of 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.

11. The cathode material of claim 1, wherein, 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 。 12. A method of producing the positive electrode material according to any one of claims 1 to 11, characterized by, The preparation method includes the following steps: 1) mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, a compound containing element M, and optionally water to obtain a mixture; 2) ball milling or grinding and sintering the mixture to obtain the lithium-rich disordered rock salt polyanion; 3) mixing the lithium-rich disordered rock salt polyanion with a carbon source and performing secondary ball milling or secondary grinding and sintering to obtain the cathode material.

13. The method of claim 12, wherein: 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 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 again in a ball mill jar to obtain the cathode material.

14. The method of claim 13, wherein: 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.

15. The method of claim 13, wherein: 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.

16. The method of claim 12, wherein: The preparation method includes the following steps: 1) mechanically mixing a lithium source, a manganese source, a fluorine source, a compound containing element X, a compound containing element M, and water to obtain a mixture; 2) grinding the mixture to obtain a slurry with a D50 particle size of 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.

17. A lithium-ion battery comprising a cathode material, characterized in that: The cathode material includes the cathode material according to any one of claims 1-11.

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