A lithium-rich material modified with lithium titanium zirconium phosphate and a preparation method thereof

Abstract

The present invention discloses a lithium titanium zirconium phosphate modified lithium-rich material and a preparation method thereof, and synthesizes an mLi[Li 0.4 Ni 0.16 Co 0.16 Mn x Zr 0.1q O2·nLiTi w Zr q (PO4)3 composite material, in which the mass percentage content of lithium titanium zirconium phosphate in the above material is 0.5-5 wt%, and the thickness is 5-20 nm. The method comprises the following steps: (1) dispersing a lithium source, a zirconium source and a phosphorus source into an organic solvent; (2) adding a titanium source and a lithium-rich material into the solution and stirring to obtain a black slurry; (3) drying in vacuum to obtain a pre-sintered product; (4) grinding and sintering in an air atmosphere to obtain a composite material. The present invention improves the electrochemical performance, rate performance and cycle performance of the lithium-rich material for lithium ion batteries. The battery assembled with the material of the present invention has a first discharge specific capacity of 255.3 mAh / g at 2.0-4.6 V and 0.1 C, and after 100 cycles at 1 C, the capacity is 224.9 mAh / g, and the capacity retention rate reaches 88.1%. The performance is excellent at high rates. The method of the present invention is simple, low in cost and less polluting to the environment, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to a cathode material for lithium-ion batteries and a preparation method thereof, and particularly relates to a lithium zirconium titanate modified lithium-rich material and a preparation method thereof. Background Art

[0002] Lithium-rich cathode materials are a new type of cathode materials for lithium-ion batteries that have developed rapidly in recent years. Among many cathode materials, lithium-rich materials with characteristics such as high capacity, low cost, and low toxicity have become a research hotspot and are expected to be used as cathode materials in next-generation high-energy-density lithium-ion batteries. However, this kind of lithium-rich material has some inherent shortcomings. For example, it has defects such as a large first irreversible capacity, poor rate performance, and a working voltage decay during cycling. These performance shortcomings limit the application of lithium-rich materials as lithium-ion cathode materials.

[0003] The modification of cathode materials is mainly doping and coating. Doping and coating can change the properties of materials, increase conductivity, cycle stability, and safety. Although the properties of materials can be changed to a certain extent, due to some factors such as experimental operations, instruments, and environmental chemicals, problems such as uneven coating layers and incomplete coating may occur, resulting in general properties of the coated materials. Therefore, the experimental conditions and coating methods should be improved accordingly.

[0004] Currently, researchers often use the coating method to modify lithium-rich materials to reduce the loss of irreversible capacity. For example, MgO, Al2O3, Fe2O3, ZnO, AlPO4, and Mg3(PO4)2 are used to coat lithium-rich materials. The coating layer minimizes the direct contact area between the electrode surface and the electrolyte, which helps prevent the material from being eroded by HF generated by side reactions.

[0005] CN 110148715A invented a preparation method of a zinc oxide-coated lithium-rich material. In the material, it includes the steps: (1) Dissolve ascorbic acid and hexamethylenetetramine in deionized water to obtain a mixed solution. According to the molar ratio (ascorbic acid: hexamethylenetetramine = 1:4.2), add lithium-rich material to the mixed solution, stir evenly, and then dropwise add zinc acetate solution. Finally, after centrifugal drying and calcination processes, a zinc oxide-coated lithium-rich material is obtained. The lithium-rich material obtained by the present invention not only has a high Coulomb efficiency, but also has a simple preparation method and low cost. At 2.5 - 4.3V and 0.1C, the first discharge specific capacity reaches 173.7 mAh / g, and after cycling 50 times, the capacity is 168 mAh / g, and the capacity retention rate reaches 96.7%. However, the discharge capacity of the obtained material at a rate of 0.1C is only 173 mAh / g, the number of cycling laps is short, and the electrochemical performance is not good. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects existing in the prior art and provide a lithium-rich composite material modified with lithium titanium zirconium phosphate and a preparation method thereof. The battery assembled with the positive composite material of the present invention has a high initial discharge capacity and good cycle stability.

[0007] The further technical problem to be solved by the present invention is to overcome the above-mentioned defects existing in the prior art and provide a preparation method of a lithium-rich composite material modified with lithium titanium zirconium phosphate. The preparation method of the present invention is simple, reasonable and has a low cost.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0009] A lithium-rich material modified with lithium titanium zirconium phosphate, with the chemical formula mLi[Li 0.4 Ni 0.16 Co 0.16 Mn x Zr 0.1q O2·nLiTi w Zr q (PO4)3 composite material, where x + 0.1q = 0.67, 0.2 ≤ q ≤ 1.9, 0.1 ≤ w ≤ 1.8, q + w = 2, 0 < n / (m + n) ≤ 0.05.

[0010] Preferably, the lithium titanium zirconium phosphate forms a uniform coating layer with a thickness of 5-20 nm in an amorphous state; the positive electrode material is secondary spherical particles with a particle size of 6-10 μm.

[0011] The further technical solution adopted by the present invention to solve its technical problems is as follows:

[0012] A preparation method of a lithium-rich material modified with lithium titanium zirconium phosphate:

[0013] (1) Disperse the lithium source and zirconium source into an organic solvent and continuously stir until evenly mixed;

[0014] (2) Disperse the phosphorus source into an organic solvent and fully stir until the phosphorus source forms a transparent and homogeneous solution;

[0015] (3) Mix the solution of (1) with that of (2) and continuously stir until uniform;

[0016] (4) Add the titanium source to the above solution and add it to the organic solvent, and continuously stir;

[0017] (5) In the suspension obtained in step (4), add Li[Li 0.4 Ni 0.16 Co 0.16 Mn 0.67 O2, adjust the appropriate solid-liquid ratio; (6) Place the obtained suspension in a magnetic stirrer and stir magnetically to obtain a black slurry;

[0018] (7) Transfer the black slurry to a vacuum chamber and dry it under vacuum to obtain a black material;

[0019] (8) Sinter the obtained lithium-rich cathode material in an air atmosphere to obtain a lithium-rich cathode material modified with lithium titanium zirconium phosphate.

[0020] Preferably, in step (1), the lithium source is one or more of lithium hydroxide, lithium carbonate, lithium nitrate, etc.

[0021] Preferably, in step (2), the phosphorus source is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphoric acid, etc., and the concentration of phosphorus is 14-16 mol / L; more preferably, the concentration of phosphorus is 15.7389 mol / L; the organic solvent is absolute ethanol.

[0022] Preferably, in step (2), the continuous stirring time is 6-15 min. The purpose is to uniformly disperse the phosphorus source in absolute ethanol to obtain a uniform solution.

[0023] Preferably, in step (4), the titanium source is one or more of tetrabutyl titanate, titanium tetrachloride, titanium isopropoxide, etc.; the continuous stirring time is 30 min. The purpose is to uniformly mix the titanium source, lithium source, zirconium source, and phosphorus source.

[0024] Preferably, in step (3), the continuous stirring time is 20-40 min. The purpose of stirring is to uniformly disperse the phosphorus source, lithium source, and zirconium source in the organic solvent, the solid-liquid ratio is 1-2:2-10, to make the stirring evaporation sufficient and the sol-gel reaction complete.

[0025] Preferably, in step (4), in the mixed solution, the molar ratio of lithium, zirconium, titanium, and phosphorus is 1-1.5:0.2-1.9:0.1-1.8:2-4. More preferably, the molar ratio of the four of lithium, zirconium, titanium, and phosphorus is 1:1.75:0.25:3.

[0026] Preferably, in step (5), the solid-liquid ratio of the lithium-rich material to the mixed solution is 1-3:5-16, more preferably, the solid-liquid ratio is 1 g:5 mL.

[0027] Preferably, in step (6), the stirring temperature is 60-85 °C, the magnetic stirring time is 3-5 h, more preferably, the temperature for evaporating the solvent is 80-85 °C, and the time is 3-4 h. Ensure uniform stirring, form a slurry-like substance, control the time, and avoid stirring without liquid.

[0028] Preferably, in step (7), the vacuum degree in the vacuum chamber is 0--0.1 MPa, the temperature is 70-130 °C, the drying time is 4-15 h, and the material is vacuum-sealed

[0029] Preferably, step (8) is characterized in that sintering is carried out in an air atmosphere at a sintering temperature of 500-1000 °C, sintering is carried out in two stages, and the sintering time is 12-20 h. More preferably, the sintering temperature is 850 °C and the sintering time is 12 h.

[0030] The experiment should be carried out in a low-humidity environment to prevent the material from absorbing water and deliquescing, which may affect subsequent experiments.

[0031] The lithium-rich cathode material used in the present invention has a secondary spherical structure, and a lithium titanium zirconium phosphate is formed on the surface of the cathode material, which improves the electrochemical performance of the lithium-rich cathode material while improving the rate performance and cycle performance, so as to be applicable to lithium-ion batteries with high specific energy density.

[0032] In summary, by adopting the technical solution of the present invention, the following beneficial effects are obtained:

[0033] (1) The present invention synthesizes a composite material of mLi[Li 0.4 Ni 0.16 Co 0.16 Mn x Zr 0.1q O2·nLiTi w Zr q (PO4)3, and the lithium titanium zirconium phosphate forms a uniform coating layer with a thickness of 5-20 nm in an amorphous state, and the cathode material is secondary spherical particles with a particle size of 6-10 μm;

[0034] (2) The lithium titanium zirconium phosphate-modified lithium-rich cathode material obtained by the present invention is assembled into a battery. At 2.0-4.6 V and 0.1 C, the initial discharge specific capacity reaches 255.3 mAh / g. After 100 cycles at 1 C, the capacity is 224.9 mAh / g, and the capacity retention rate reaches 88.1%. This shows that the lithium titanium zirconium phosphate-modified lithium-rich cathode composite material of the present invention has good cycle stability and high-rate discharge performance.

[0035] (3) The preparation process of the present invention is simple, with low cost and less environmental pollution, and is suitable for industrial production. Description of the Drawings

[0036] Figure 1 is the TEM image of the cathode composite material obtained in Example 1 of the present invention;

[0037] Figure 2 is the XRD pattern of the cathode composite material obtained in Example 1 of the present invention;

[0038] Figure 3 is the low-magnification SEM image of the lithium-rich material obtained in Example 4 of the present invention;

[0039] Figure 4It is the high magnification SEM image of the lithium-rich material obtained in Example 4 of the present invention;

[0040] Figure 5 It is the cycling performance graph of the cathode composite material and the lithium-rich cathode material in Example 1 and Example 4 of the present invention; Detailed implementation manners

[0041] The present invention will be further described below in conjunction with embodiments and drawings.

[0042] The lithium-rich cathode material precursor used can be synthesized or directly purchased. The lithium-rich used in this experiment was purchased from Zhejiang Pawva Co., Ltd.; other chemical reagents used in the present invention were all obtained through conventional commercial channels.

[0043] Example 1

[0044] A lithium-rich material modified with lithium titanium zirconium phosphate: The chemical formula of the composite material is mLi[Li 0.4 Ni 0.16 Co 0.16 Mn 0.495 Zr 0.175 O2·nLiTi 0.25 Zr 1.75 (PO4)3, n / (m + n)=0.01, the mass percentage content of the lithium titanium zirconium phosphate is 1wt%, and the lithium titanium zirconium phosphate forms a uniform coating layer with a thickness of 10 nm in an amorphous state; the cathode material is secondary spherical particles with a particle size of 6-10 μm.

[0045] As Figure 1 shown, the thickness of the lithium titanium zirconium phosphate coating layer on the surface of the cathode composite material obtained in Example 1 of the present invention is 10 nm.

[0046] As Figure 2 shown, the cathode composite material obtained in the invention example contains lithium titanium zirconium phosphate components and is a pure phase.

[0047] As Figure 5 shown, for the lithium-rich material modified with lithium titanium zirconium phosphate obtained in the invention example, the capacity retention rate reaches 88.1% after 100 cycles.

[0048] Preparation method of lithium-rich cathode material modified by lithium titanium zirconium phosphate: (1) Disperse 0.0298 g (0.4322 mmol) of lithium nitrate and 0.3242 g (0.7551 mmol) of zirconium nitrate into absolute ethanol, and continuously stir for 30 min until evenly mixed to obtain a mixed solution; (2) Disperse 0.1269 g (1.2949 mmol) of phosphoric acid into 10 ml of absolute ethanol, and fully stir until the phosphorus source becomes a transparent and homogeneous solution; (3) Mix the solution in step (2) with the solution in step (1), and continuously stir until homogeneous; (4) Add 0.0367 g (0.1078 mmol) of tetrabutyl titanate (density 0.966 g / cm3) to the above solution, and add 10 mL of absolute ethanol; (5) In the suspension obtained in step (4), add 19.8 g of lithium-rich material, and add 30 ml of absolute ethanol to make the solid-liquid ratio 1:5; (6) Place the obtained suspension in a magnetic stirrer, stir magnetically at 80 °C for 3 hours to obtain a black slurry; (7) Transfer the black slurry to a vacuum chamber, vacuum dry at -0.1 MPa and 100 °C for 8 hours to obtain a black material. (8) Place the obtained lithium-rich cathode material in a mortar, grind for 10 min, and sinter at 850 °C for 12 h in an air atmosphere to obtain a lithium-rich cathode material modified by lithium titanium zirconium phosphate.

[0049] Assembly of battery: Weigh 0.32 g of the lithium-rich cathode material modified by lithium titanium zirconium phosphate obtained in the present invention, add 0.04 g of acetylene black as a conductive agent and 0.04 g of PVDF (polyvinylidene fluoride) as a binder, grind the materials evenly, add an appropriate amount of NMP and mix evenly, then evenly coat it on an aluminum foil to make a positive electrode sheet. In a vacuum glove box, use a lithium metal sheet as the negative electrode, Celgard 2300 as the separator, and 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1) as the electrolyte to assemble a CR2025 button battery.

[0050] For the assembled battery, in the voltage range of 2.0 - 4.6 V and at a 0.1C rate, the initial discharge specific capacity reaches 255.3 mAh / g. After cycling 100 times at 1C, the capacity is 224.9 mAh / g, and the capacity retention rate reaches 88.1%.

[0051] Example 2

[0052] A lithium-rich material modified by lithium titanium zirconium phosphate: The chemical formula of the composite material is mLi[Li 0.4 Ni 0.16 Co 0.16 Mn 0.48 Zr 0.19 O2·nLiTi 0.1 Zr 1.9(PO4)3, n / (m + n) = 0.015, the mass percentage of lithium titanium zirconium phosphate is 1.5 wt%, and the lithium titanium zirconium phosphate forms a uniform coating layer in an amorphous state; the cathode material is secondary spherical particles with a particle size of 6 - 10 μm.

[0053] It was detected that the lithium titanium zirconium phosphate - modified lithium - rich material obtained in the embodiment of the present invention contains lithium titanium zirconium phosphate components and is a pure phase.

[0054] It was detected that the lithium titanium zirconium phosphate - modified lithium - rich material obtained in the embodiment of the present invention is secondary spherical particles with a particle size of 6 - 10 μm, and there is a coating layer formed by lithium titanium zirconium phosphate in an amorphous state on the surface.

[0055] It was detected that the thickness of the lithium titanium zirconium phosphate coating layer on the surface of the lithium titanium zirconium phosphate - modified lithium - rich material obtained in the embodiment of the present invention is uniform.

[0056] A preparation method of a lithium titanium zirconium phosphate - modified lithium - rich material: (1) Disperse 0.0236 g (0.3194 mmol) of lithium carbonate and 0.5207 g (1.2128 mmol) of zirconium nitrate into absolute ethanol, and continuously stir for 40 min until evenly mixed to obtain a mixed solution; (2) Disperse 0.2203 (1.9151 mmol) of ammonium dihydrogen phosphate into 10 ml of absolute ethanol, and fully stir until the phosphorus source becomes a transparent and homogeneous solution; (3) Mix the solution in step two with the solution in step one, and continuously stir until uniform; (4) Add 0.0121 (0.0638 mmol) of titanium tetrachloride to the above - mentioned solution, and add 10 mL of absolute ethanol; (5) In the milky white suspension obtained in step (4), add 19.7 g of lithium - rich material, and add 30 ml of absolute ethanol to make the solid - liquid ratio 1:5; (6) Place the obtained suspension in a magnetic stirrer, and stir magnetically at 70 °C for 4.5 hours to obtain a black slurry; (7) Transfer the black slurry to a vacuum box, vacuum - dry at - 0.05 MPa and 90 °C for 7.5 hours to obtain a black material. (8) Place the obtained lithium - rich cathode material in a mortar, grind for 11 min, and sinter at 750 °C for 12 h in an air atmosphere to obtain a lithium titanium zirconium phosphate - modified lithium - rich material.

[0057] Assembly of the battery: Weigh 0.32 g of the lithium titanium zirconium phosphate - modified lithium - rich material obtained in the present invention, add 0.04 g of acetylene black as a conductive agent and 0.04 g of PVDF (polyvinylidene fluoride) as a binder, grind the materials evenly, add an appropriate amount of NMP and mix evenly, then uniformly coat it on an aluminum foil to make a positive electrode sheet. In a vacuum glove box, use a lithium metal sheet as the negative electrode, Celgard 2300 as the separator, and 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1) as the electrolyte to assemble a CR2025 button cell.

[0058] The assembled battery has an initial discharge specific capacity of 248.2 mAh / g at a rate of 0.1C within the voltage range of 2.0 - 4.6V.

[0059] Example 3

[0060] A lithium-rich material modified with lithium titanium zirconium phosphate: The chemical formula of the composite material is mLi[Li 0.4 Ni 0.16 Co 0.16 Mn 0.49 Zr 0.18 O2·nLiTi 0.2 Zr 1.8 (PO4)3, n / (m + n) = 0.005, the mass percentage of lithium titanium zirconium phosphate is 0.5 wt%, and lithium titanium zirconium phosphate forms a uniform coating layer in an amorphous state; the cathode material is secondary spherical particles with a particle size of 6 - 10 μm, and lithium titanium zirconium phosphate forms a uniform coating layer with a thickness of 8 nm in an amorphous state.

[0061] After testing, the lithium-rich material modified with lithium titanium zirconium phosphate obtained in the embodiment of the present invention is secondary spherical particles with a particle size of 6 - 10 μm, and there is a coating layer formed by lithium titanium zirconium phosphate in an amorphous state on the surface.

[0062] After testing, the thickness of the lithium titanium zirconium phosphate coating layer on the surface of the lithium-rich material modified with lithium titanium zirconium phosphate obtained in the embodiment of the present invention is uniform.

[0063] After testing, the lithium-rich material modified with lithium titanium zirconium phosphate obtained in the embodiment of the present invention contains lithium titanium zirconium phosphate components and is a pure phase.

[0064] A preparation method of a lithium-rich material coated with lithium titanium zirconium phosphate: (1) Disperse 0.0060 g (0.2505 mmol) of lithium hydroxide and 0.0217 g (0.0505 mmol) of zirconium nitrate into anhydrous ethanol, and continuously stir for 43 min until evenly mixed to obtain a mixed solution; (2) Disperse 0.1000 g (0.7572 mmol) of diammonium hydrogen phosphate into 5 ml of anhydrous ethanol, and stir thoroughly until the phosphorus source becomes a transparent and homogeneous solution; (3) Mix the solution in step two with the solution in step one, and continuously stir until uniform; (4) Add 0.1289 g of titanium isopropoxide to the above solution, and add 5 mL of anhydrous ethanol; (5) In the suspension obtained in step (4), add 19.9 g of lithium-rich material, and add 40 ml of anhydrous ethanol to make the solid-liquid ratio 1:6; (6) Place the obtained suspension in a magnetic stirrer, and stir magnetically at 90 °C for 3 hours to obtain a black slurry; (7) Transfer the black slurry to a vacuum box, vacuum dry at 0 MPa and 120 °C for 6 hours to obtain a black material. (8) Place the obtained lithium-rich cathode material in a mortar, grind for 10 min, and sinter at 900 °C for 11 h in an air atmosphere to obtain a lithium-rich cathode material modified with lithium titanium zirconium phosphate.

[0065] Assembly of the battery: Weigh 0.32 g of the lithium-rich material modified with lithium titanium zirconium phosphate obtained in the present invention, add 0.04 g of acetylene black as a conductive agent and 0.04 g of PVDF (polyvinylidene fluoride) as a binder, grind the materials evenly, add an appropriate amount of NMP and mix evenly, and then evenly coat it on an aluminum foil to make a positive electrode sheet. In a vacuum glove box, use a lithium metal sheet as the negative electrode, Celgard 2300 as the separator, and 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1) as the electrolyte to assemble a CR2025 coin cell.

[0066] For the assembled battery, in the voltage range of 2.0 - 4.6 V and at a rate of 0.1C, the initial discharge specific capacity is 246.2 mAh / g.

[0067] Example 4

[0068] An unmodified lithium-rich cathode material: The chemical formula of the material is Li[Li 0.4 Ni 0.16 Co 0.16 Mn 0.67 O2, and the cathode material is secondary spherical particles with a particle size of 6 - 10 μm.

[0069] As Figure 3 and Figure 4 shown, the Li[Li 0.4 Ni 0.16 Co 0.16 Mn 0.67 O2 lithium-rich material obtained in Example 1 of the present invention is secondary spherical particles with a particle size of 6 - 10 μm.

[0070] As Figure 5 shown, the capacity retention rate of the unmodified lithium-rich cathode material of lithium titanium zirconium phosphate in the invention is only 85.4% after 100 cycles.

[0071] A preparation method of an uncoated lithium-rich cathode material: (1) Place 20 g of the lithium-rich material in a mortar, grind it for 10 min, and sinter it at 800 °C for 10 h in an air atmosphere to obtain an unmodified secondary spherical lithium-rich cathode material.

[0072] Assembly of the battery: Weigh 0.32 g of the lithium-rich cathode material, add 0.04 g of acetylene black as a conductive agent and 0.04 g of PVDF (polyvinylidene fluoride) as a binder, grind the materials evenly, add an appropriate amount of NMP and mix evenly, and then evenly coat it on an aluminum foil to make a positive electrode sheet. In a vacuum glove box, use a lithium metal sheet as the negative electrode, Celgard 2300 as the separator, and 1 mol / L LiPF6 / EC:DMC (volume ratio 1:1) as the electrolyte to assemble a CR2025 coin cell.

[0073] As shown in the figure, within the voltage range of 2.0 - 4.6V, at a rate of 0.1C, the initial discharge capacity of the battery is 258.2 mAh / g. After 100 cycles, the capacity decays to 220.5 mAh / g, and the capacity retention rate is only 85.4%.

[0074] In summary, the lithium-rich cathode composite material modified by lithium zirconium titanate phosphate has been greatly improved in both cycling performance and rate performance.

Claims

1. A lithium-rich material modified with lithium zirconium titanium phosphate, characterized in that: Chemical formula mLi[Li 0.4 Ni 0.16 Co 0.16 Mn x Zr 0.1q O2·nLiTi w Zr q (PO4)3 composite material, where x + 0.1q = 0.67, 0.2 ≤ q ≤ 1.9, 0.1 ≤ w ≤ 1.8, q + w = 2, 0 < n / (m + n) ≤ 0.

05.

2. The material according to claim 1, wherein the lithium titanium zirconium phosphate has a mass percentage content of 0.5 to 5 wt%, and the lithium titanium zirconium phosphate forms a uniform coating layer with a thickness of 5 to 20 nm in an amorphous state; the material is secondary spherical particles with a particle size of 6 to 10 μm.

3. The preparation method of a lithium-rich material modified with lithium titanium zirconium phosphate according to claim 1 or 2, characterized in that, The preparation method comprises the following steps: (1) Obtain a lithium-rich material precursor; (2) Disperse a lithium source and a zirconium source into an organic solvent, and continuously stir until uniformly mixed; (3) Disperse a phosphorus source into an organic solvent, and fully stir until the phosphorus source forms a transparent and uniform solution; (4) Mix the solution in step (3) with the solution in step (2), and continuously stir until uniform; (5) Add a titanium source to the above solution, and add an organic solvent; (6) Add the lithium-rich material to the suspension obtained in step (5), and add an organic solvent to adjust the solid-liquid ratio; (7) Place the obtained suspension in a magnetic stirrer and magnetically stir to obtain a black slurry; (8) Transfer the black slurry to a vacuum box and vacuum dry to obtain a black material; (9) Place the obtained cathode material in a mortar and grind it, and sinter it in an air atmosphere to obtain a lithium-rich material modified with lithium titanium zirconium phosphate.

4. The preparation method of the lithium-rich material modified with lithium zirconium phosphate according to claim 3, wherein: In step (2), the organic solvent is anhydrous ethanol; the lithium source is one or more of lithium hydroxide, lithium carbonate or lithium nitrate; the zirconium source is zirconium nitrate, and the continuous stirring time is 6 to 15 min; in step (3), the phosphorus source is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate or phosphoric acid, and the concentration of phosphorus is 14 to 16 mol / L; in step (5), the titanium source is one or more of tetrabutyl titanate, titanium tetrachloride or titanium isopropoxide.

5. The preparation method of the lithium-rich material modified with lithium zirconium phosphate according to claim 3, characterized in that, In the mixed solution, the molar ratio of lithium, zirconium, titanium and phosphorus is 1 to 1.5: 0.2 to 1.9: 0.1 to 1.8: 2 to 4; in step (6), the solid-liquid ratio is 1 to 2: 6 to 15.

6. The preparation method of the lithium-rich material modified by lithium zirconium titanium phosphate according to claim 3, characterized in that The vacuum drying is carried out in a vacuum box, the vacuum degree is 0 to -0.1 MPa, the temperature is 70 to 130 °C, the drying time is 4 to 15 h, and the material is vacuum sealed.

7. The preparation method of the lithium-rich material modified with lithium titanium zirconium phosphate according to claim 3, characterized in that, The dropping rate of the organic solvent is from 0.5 ml / min to 2 ml / min, and the solid-liquid ratio of the lithium-rich material to the mixed solution is 1 to 2: 5 to 15.

8. The preparation method of the lithium-rich material modified with lithium zirconium phosphate according to claim 3, characterized in that, The stirring temperature is 60 to 85 °C, the magnetic stirring time is 3 to 5 h; stir evenly to form a paste-like substance, and control the time to make the slurry 5 to 15 ml.

9. The preparation method of the lithium-rich material modified with lithium titanium zirconium phosphate according to claim 3, wherein, Sintering is carried out in an air atmosphere, the sintering temperature is 500 °C to 1000 °C, sintering is carried out in two stages, and the sintering time is 10 to 20 h.

10. The preparation method of the lithium-rich material modified with lithium titanium zirconium phosphate according to claim 3, wherein The mass percentage content of lithium titanium zirconium phosphate is 0.5% to 1.5%; the experiment process should be carried out in an environment with a humidity of 3% to 8%.

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