Preparation method of torispherical Li1. 3Al0. 3Ti1. 7 (PO4) 3 ultrafine powder

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of torispherical Li1. 3Al0. 3Ti1. 7 (PO4) 3 ultrafine powder. According to the specific technical scheme, the method comprises the following steps: adding a Li source solution, an Al source solution, a Ti source solution and a PO4 source solution into water, stirring, and calcining a sample solution in two stages to obtain Li1. 3Al0. 3Ti1. 7 (PO4) 3 coarse grains; and grinding the coarse grains to obtain the Li1. 3Al0. 3Ti1. 7 (PO4) 3 ultrafine powder. The first-stage calcination temperature is 300-400 DEG C, and the calcination time is 6-8 hours; the calcining temperature of the second stage is 800-1000 DEG C, and the calcining time is 8-10 hours. According to the method, different raw materials are simultaneously and continuously dropwise added, and the concentration and the dripping speed of the raw materials are strictly controlled, so that the stoichiometric ratio equilibrium and the equilibrium concentration among the substances participating in the reaction are accurately controlled, the formation of by-products is favorably reduced, and the purity of the product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly relates to a method for preparing quasi-spherical Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder. Background Art

[0002] Lithium-ion batteries are currently widely used in various fields such as various electronic devices, electric vehicles, aerospace, etc. Most of the currently mainstream lithium-ion batteries use liquid electrolytes, such as the combination of LiPF6 and carbonate-based organic solutions. Such liquid electrolytes will cause uncontrolled growth of lithium dendrites during uneven charge and discharge, and are prone to piercing the separator, resulting in huge safety hazards (Z.Y. Wang, Z.X. Lu, W. Guo, et al. A Dendrite-Free Lithium / CarbonNanotube Hybrid for Lithium-Metal Batteries. [J]. Advanced Materials, 2021, 33: 2006702; S. Sen, F.H. Richter. Typology of Battery Cells-From Liquid to SolidElectrolytes. [J]. Advanced Science, 2023, 10(33): e2303985; C.F.J. Francis, I.L. Kyratzis, A.S. Best. Lithium-Ion Battery Separators for Ionic-LiquidElectrolytes: A Review. [J]. Advanced Materials, 2020, 32(18): e1904205.).

[0003] Compared with liquid lithium-ion batteries, all-solid-state lithium-ion batteries have higher safety, stability and cycle life. The preparation of high-performance solid-state lithium-ion conductors is the key material for realizing all-solid-state lithium-ion batteries. Currently, scientists have developed solid-state lithium-ion conductors with various structures, such as Li7La3Zr2O 12 ,Li 3x La 2 / 3-x Zr 1 / 3-2x TiO3,Li 1.3 Al 0.3 Ti 1.7(PO4)3 etc. (J. Awaka, N. Kijima, H. Hayakawa, et al. Synthesis and Structure Analysis of Tetragonal Li7La3Zr2O 12 with the Garnet-related Type Structure. [J]. Journal of Solid State Chemistry, 2009, 182(8): 2046 - 2052; K. W. Ju, K. Hyeongil, J. K. Nam, et al. Enhanced Li + conduction in perovskite Li 3x La 2 / 3-x Zr 1 / 3-2x TiO3 solid - electrolytes via microstructural engineering. [J]. Journal of Materials Chemistry A, 2017, 5(13): 6257 - 6262; M. Yedukondalu, J. Anirudha, C. Ho, et al. Recent Advancements in Li - Ion Conductors for All - Solid - State Li - Ion Batteries. [J]. ACS Energy Letters, 2017, 2(12): 2734 - 2751.). Among them, Li 1.3 Al 0.3 Ti 1.7(PO4)3(LATP) has three-dimensionally connected cavities, and has the advantages of stable chemical properties, wide electrochemical window, high ionic conductivity, etc. It is an excellent candidate material for solid-state lithium ion conductors (S.P.Shen, G.Tang, H.J.Li, et al. Low-temperature fabrication of NASICON-type LATP with superior ionic conductivity. [J]. Ceramics International, 2022, 48(24): 36961-36867.). Its common preparation methods mainly include solid-phase sintering method and liquid-phase sol-gel method. Among them, the solid-phase sintering preparation method has problems such as easy loss of raw materials and insufficient product purity caused by uneven mixing (C.W.Luo, G.Q.Zhao, M.Y.Zhang, et al. Facile Route to Synthesize a Highly Sinterable Li 1.3 Al 0.3 Ti 1.7 (PO4)3 Solid Electrolyte. [J]. ACS Applied Materials & Interfaces, 2024, 16(3): 3289-3301; O.M. et al. Structure and Ionic Conductivity of NASICON-type LATP Solid Electrolytes Synthesized by the Solid-State Method. [J]. Ceramics International, 2024, 50(17PB): 31435 - 31441; A.M. Segarra, S.F. Nicomedes, N.V. Agut, et al. The Role of the LATP Particle Size as a Cornerstone of the Cold Sintering Process. [J]. Journal of the European Ceramic Society, 2024, 44(8): 5105 - 5114.). And the sol - gel method can make the raw materials be mixed evenly at the molecular or near - molecular level, which is beneficial to improving the product purity and controlling its morphology. The specific method is to slowly drip the anionic precipitant into the cationic solution under rapid stirring (positive dripping method). The uneven local concentration is likely to cause the product to deviate from its stoichiometric ratio and widen the product particle size distribution, both of which will affect the final lithium - ion conduction performance of the material (E.C. Bucharsky, K.G. Schell, A. Hintennach, et al. Preparation and Characterization of Sol - gel Derived High Lithium Ion Conductive NZP - type Ceramics Li 1+x Al x Ti 2-x (PO4)3. [J]. Solid State Ionics, 2015, 274: 77 - 82; M. Monchak, T. Hupfer, A. Senyshyn, et al. Lithium Diffusion Pathway in Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP) Superionic Conductor. [J]. Inorganic Chemistry, 2016, 55(6): 2941 - 2945; P. Bharathi, S.F. Wang. Nanoscale Synthesis of Li 1.3 Al 0.3 Ti 1.7(PO4)3 Solid-State Lithium Ion Battery Electrolyte: A Structural and Ionic Conductivity Study. [J]. ACS Applied Nano Materials, 2024, 7(2): 1615-1624.). Therefore, further development of high-purity nano Li with controllable morphology and size 1.3 Al 0.3 Ti 1.7 (PO4)3 particles is crucial for realizing its wide practical applications.. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a method for preparing quasi-spherical Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] The present invention discloses a method for preparing quasi-spherical Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder. Add the Li source solution, Al source solution, Ti source solution and PO4 source solution into water. After stirring, the sample solution is calcined in two stages. After calcination, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 coarse particles are obtained; after grinding the coarse particles, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder is obtained;

[0007] The calcination temperature of the first stage is 300-400 °C, and the calcination time is 6-8 h; the calcination temperature of the second stage is 800-1000 °C, and the calcination time is 8-10 h.

[0008] Preferably, the Li source is at least one of lithium acetate, lithium carbonate, lithium chloride, lithium bromide, lithium acetate, lithium sulfate, lithium lactate;

[0009] The Al source is at least one of aluminum nitrate, aluminum tri-sec-butoxide, aluminum sulfate, aluminum chloride, triethylaluminum, triisobutylaluminum, diethylaluminum chloride;

[0010] The Ti source is at least one of tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, titanium oxychloride, titanium tetrachloride;

[0011] The PO4 source is at least one of ammonium phosphate, ammonium dihydrogen phosphate, sodium tripolyphosphate, and ammonium polyphosphate.

[0012] Preferably, the ratio of lithium in the Li source, aluminum in the Al source, and titanium in the Ti source is calculated according to the stoichiometric ratio of 13:3:17:30 of the target molecule, and the molar dosage of the PO4 source is 1.00 - 1.15 times the required dosage for preparing Li 1.3 Al 0.3 Ti 1.7 (PO4)3.

[0013] Preferably, the concentration of the Li source is 0.08 - 0.15 mol / L, the concentration of the Al source is 0.015 - 0.030 mol / L, the concentration of the Ti source is 0.120 - 0.140 mol / L, and the concentration of the PO4 source is 0.210 - 0.252 mol / L.

[0014] Preferably, the Li source solution, Al source solution, Ti source solution, and PO4 source solution are simultaneously dropped into water in a dropping manner.

[0015] Preferably, the dropping rate of the Li source solution is 12 - 15 ml / min, the dropping rate of the Al source solution is 6 - 12 ml / min, the dropping rate of the Ti source solution is 6 - 12 ml / min, and the dropping rate of the PO4 source solution is 3 - 6 ml / min.

[0016] Preferably, the rotation speed of the grinding is 300 - 500 r / min.

[0017] Preferably, the 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder has a particle size of 100 - 600 nm.

[0018] The present invention has the following beneficial effects:

[0019] Different from the traditional positive dropping method of dropping anions into a cation solution to form a precipitate, the present invention precisely controls the stoichiometric ratio balance and equilibrium concentration between the substances participating in the reaction by simultaneously and continuously dropping different raw materials and strictly controlling their concentrations and dropping rates. On the one hand, this is conducive to reducing the formation of by-products and improving the purity of the product; on the other hand, by simultaneously dropping, the supersaturation of LATP nucleation is strictly controlled, promoting the rapid formation of a large number of reaction nuclei and inhibiting the subsequent growth rate, thereby better controlling the morphology and particle size of the product, making the generated sample have a smaller particle size and a more uniform distribution, and finally making the uniformity and consistency of the LATP material meet the actual application requirements. Description of the Drawings

[0020] Figure 1SEM images of the ultrafine powder prepared in Example 1; a: LATP sample sintered at 400 °C for 6 h and then calcined at 1000 °C for 10 h, with an average particle size of 1.5 μm; b: LATP sample sintered at 400 °C for 6 h, then calcined at 1000 °C for 10 h, and subsequently ball-milled at a rotation speed of 300 r / min for 6 h, with an average particle size of 200 nm;

[0021] Figure 2 Infrared spectra of the samples prepared at different calcination temperatures and times in Example 1, Example 8, and Example 9; a: LATP powder heat-treated at 400 °C for 8 h and then at 800 °C for 8 h; b: LATP powder heat-treated at 400 °C for 7 h and then at 900 °C for 9 h and then ultrasonically crushed; c: LATP powder heat-treated at 400 °C for 6 h and then at 1000 °C for 10 h; No impurity peaks were found in the infrared spectra.

[0022] Figure 3 XRD patterns of the samples prepared at different concentrations of ammonium dihydrogen phosphate in Example 1, Example 10, and Example 11. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0025] The present invention discloses a method for preparing quasi-spherical Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder. The steps are as follows: simultaneously drop the Li source solution, Al source solution, Ti source solution, and PO4 source solution into a small amount of water at a certain dropping rate and stir. The obtained sample solution is calcined in two stages, and after calcination, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 coarse grains are obtained; after grinding the coarse grains, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder is obtained. The rotation speed of grinding is 300 - 500 r / min, and the grinding time can be adjusted according to the actual situation until the LATP powder is ground to the required particle size. The Li 1.3Al 0.3 Ti 1.7 (PO4)3 ultrafine powder has a quasi-spherical morphology, a particle size of 100 - 600 nm, and a purity of over 99%.

[0026] The calcination temperature in the first stage is 300 - 400 °C, and the calcination time is 6 - 8 h; the calcination temperature in the second stage is 800 - 1000 °C, and the calcination time is 8 - 10 h.

[0027] Furthermore, the Li source is at least one of lithium acetate, lithium carbonate, lithium chloride, lithium bromide, lithium acetate, lithium sulfate, lithium lactate;

[0028] The Al source is at least one of aluminum nitrate, aluminum tri-sec-butoxide, aluminum sulfate, aluminum chloride, triethylaluminum, triisobutylaluminum, diethylaluminum chloride;

[0029] The Ti source is at least one of tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, titanium oxychloride, titanium tetrachloride;

[0030] The PO4 source is at least one of ammonium phosphate, ammonium dihydrogen phosphate, sodium tripolyphosphate, ammonium polyphosphate.

[0031] Furthermore, the ratio of lithium in the Li source, aluminum in the Al source, and titanium in the Ti source is calculated according to the stoichiometric ratio of 13:3:17:30 of the target molecule, and the molar dosage of the PO4 source is 1.00 - 1.15 times the required dosage for preparing Li 1.3 Al 0.3 Ti 1.7 (PO4)3. When adding the PO4 source solution, it needs to be slightly in excess. Too little may cause some unreacted TiO2 impurities and some LiTiOPO4 impurities in the impurities; too much PO4 will also cause the formation of by-product AlPO4.

[0032] Furthermore, the concentration of the Li source is 0.08 - 0.15 mol / L, the concentration of the Al source is 0.015 - 0.030 mol / L, the concentration of the Ti source is 0.120 - 0.140 mol / L, and the concentration of the PO4 source is 0.210 - 0.252 mol / L.

[0033] Furthermore, the dropping rate of the Li source solution is 12 - 15 ml / min, the dropping rate of the Al source solution is 6 - 12 ml / min, the dropping rate of the Ti source solution is 6 - 12 ml / min, and the dropping rate of the PO4 source solution is 3 - 6 ml / min.

[0034] The following further elaborates the present invention in combination with specific embodiments.

[0035] Example 1

[0036] Li 1.3 Al 0.3 Ti 1.7 (Preparation of Li

[0037] (1) 50 ml of 0.1 mol / L lithium acetate dihydrate solution, 25 ml of 0.046 mol / L aluminum tri-sec-butoxide (using ethanol as the solvent), 25 ml of 0.262 mol / L titanium tetraisopropoxide solution (using ethanol as the solvent), and 55 ml of 0.231 mol / L ammonium dihydrogen phosphate solution were simultaneously added dropwise to a 250 ml conical flask containing 20 ml of water by peristaltic pumps at dropping rates of 12 ml / min, 12 ml / min, 12 ml / min, and 3 ml / min respectively, and a magnetic stirrer was added and continuously stirred.

[0038] (2) Stir continuously for 2 h at room temperature. After 2 h, take out the magnetic stirrer and dry it in an oven at 80 °C.

[0039] (3) Calcinate at 400 °C for 6 h in a muffle furnace, and then calcinate at 1000 °C for 10 h to form crystals.

[0040] (4) Then take out 5 g of the generated crystals and mix them with 50 ml of ethanol, ball mill at a rotation speed of 300 r / min for 6 h in a ball mill, and finally dry in an oven at 80 °C. Li 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor can be obtained, and the infrared spectrum image is shown in Figure 2 .

[0041] According to the above preparation method, the XRD patterns of Li 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductors prepared at different concentrations of ammonium dihydrogen phosphate are as shown in Figure 3 . Among them, a: the concentration of ammonium dihydrogen phosphate added is 0.231 mol / L, and the added amount is 55 ml. b: the concentration of ammonium dihydrogen phosphate added is 0.210 mol / L, and the added amount is 55 ml. It can be known from the phase analysis that the impurity peaks are SiO2 and LiTiOPO4. c: the concentration of ammonium dihydrogen phosphate added is 0.252 mol / L, and the added amount is 55 ml. It can be known from the phase analysis that the impurity peak is AlPO4.

[0042] Example 2

[0043] Same as Example 1, except that: the Al source is aluminum nitrate, and finally Li 1.3 Al 0.3 Ti1.7 (PO4)3 lithium ion conductor.

[0044] Example 3

[0045] Same as Example 1, except that the dropping rate of aluminum tri-sec-butoxide is 6 ml / min, and finally Li with a particle size of 300 - 500 nm is obtained 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0046] Example 4

[0047] Same as Example 1, except that the dropping rate of titanium tetraisopropoxide solution is 6 ml / min, and finally Li with a particle size of 300 - 500 nm is obtained 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0048] Example 5

[0049] Same as Example 1, except that the dropping rate of ammonium dihydrogen phosphate solution is 6 ml / min, and finally Li with a particle size of 300 - 500 nm is obtained 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0050] Example 6

[0051] Same as Example 1, except that step (3) is: calcine in a muffle furnace at 300 °C for 6 h, and then calcine at 800 °C for 10 h to crystallize, and finally Li with a particle size of 200 - 400 nm is obtained 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0052] Example 7

[0053] Same as Example 6, except that step (3) is: calcine in a muffle furnace at 300 °C for 8 h, and then calcine at 800 °C for 10 h to crystallize, and finally Li with a particle size of 200 - 400 nm is obtained 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0054] Example 8

[0055] Same as Example 1, except that: Step (3) is: calcine in a muffle furnace at 400 °C for 8 h, then calcine at 800 °C for 8 h to form crystals, and finally obtain Li with a particle size of 200 - 400 nm 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor. See the infrared spectrum image in Figure 2 .

[0056] Example 9

[0057] Same as Example 1, except that: Step (3) is: calcine in a muffle furnace at 400 °C for 7 h, then calcine at 900 °C for 9 h to form crystals, and finally obtain Li with a particle size of 200 - 400 nm 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor. See the infrared spectrum image in Figure 2 .

[0058] Example 10

[0059] Same as Example 1, except that the concentration of ammonium dihydrogen phosphate solution is 0.210 mol / l. See the XRD image in Figure 3 , and the results show that there are impurities of TiO2 and some LiTiOPO4.

[0060] Example 11

[0061] Same as Example 1, except that the concentration of ammonium dihydrogen phosphate solution is 0.252 mol / l. See the XRD image in Figure 3 , and the results show that there is AlPO4.

[0062] Example 12

[0063] Same as Example 1, except that the concentration of lithium acetate dihydrate solution is 0.08 mol / l, and finally obtain Li with a particle size of 200 - 400 nm 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0064] Example 13

[0065] Same as Example 1, except that the concentration of lithium acetate dihydrate solution is 0.15 mol / l, and finally obtain Li with a particle size of 200 - 400 nm 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0066] Example 14

[0067] Same as Example 1, except that the concentration of the aluminum tri-sec-butoxide solution (using ethanol as the solvent) is 0.015 mol / l, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0068] Example 15

[0069] Same as Example 1, except that the concentration of the aluminum tri-sec-butoxide solution (using ethanol as the solvent) is 0.030 mol / l, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0070] Example 16

[0071] Same as Example 1, except that the concentration of the titanium tetraisopropoxide solution (using ethanol as the solvent) is 0.120 mol / l, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0072] Example 17

[0073] Same as Example 1, except that the concentration of the titanium tetraisopropoxide solution (using ethanol as the solvent) is 0.140 mol / l, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0074] Example 18

[0075] Same as Example 1, except that the rotation speed of the ball mill is 500 r / min, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0076] Example 19

[0077] Same as Example 1, except that the ball milling time is 8 h, and finally Li with a particle size of 200 - 400 nm is obtained. 1.3 Al 0.3 Ti 1.7 (PO4)3 lithium ion conductor.

[0078] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A quasi-spherical Li 1.3 Al 0.3 Ti 1.7 The method for preparing (PO4)3 ultrafine powder is characterized by: Li source solution, Al source solution, Ti source solution and PO4 source solution were added into water and stirred. The sample solution was calcined in two stages to obtain Li 1.3 Al 0.3 Ti 1.7 (PO4)3 coarse particles; after grinding the coarse particles, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 ultrafine powder; The calcination temperature of the first stage is 300-400°C, and the calcination time is 6-8h; the calcination temperature of the second stage is 800-1000°C, and the calcination time is 8-10h.

2. The preparation method according to claim 1, characterized in that: The Li source is at least one of lithium acetate, lithium carbonate, lithium chloride, lithium bromide, lithium acetate, lithium sulfate, and lithium lactate; The Al source is at least one of aluminum nitrate, tri-sec-butyl aluminum, aluminum sulfate, aluminum chloride, triethyl aluminum, triisobutyl aluminum, and diethyl aluminum chloride; The Ti source is at least one of tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, titanium oxychloride, and titanium tetrachloride; The PO4 source is at least one of ammonium phosphate, diammonium phosphate, sodium tripolyphosphate, and ammonium polyphosphate.

3. The preparation method according to claim 1, characterized in that: The ratio of lithium in the Li source, titanium in the Al source and titanium in the Ti source is calculated according to the stoichiometric ratio of the target molecule 13:3:17:30, and the molar amount of the PO4 source is for preparing Li 1.3 Al 0.3 Ti 1.7 1.00 to 1.15 times the required amount of (PO4)3.

4. The preparation method according to claim 1 or 3, characterized in that: The concentration of the Li source is 0.08-0.15 mol / L, the concentration of the Al source is 0.015-0.030 mol / L, the concentration of the Ti source is 0.120-0.140 mol / L, and the concentration of the PO4 source is 0.210-0.252 mol / L.

5. The preparation method according to claim 1, characterized in that: The Li source solution, Al source solution, Ti source solution and PO4 source solution are simultaneously dropped into water in a dropwise manner.

6. The preparation method according to claim 5, characterized in that: The dripping rate of the Li source solution is 12-15 ml / min, the dripping rate of the Al source solution is 6-12 ml / min, the dripping rate of the Ti source solution is 6-12 ml / min, and the dripping rate of the PO4 source solution is 3-6 ml / min.

7. The preparation method according to claim 1, characterized in that: The grinding speed is 300-500 r / min.

8. The preparation method according to claim 1, characterized in that: The Li 1.3 Al 0.3 Ti 1.7 The particle size of (PO4)3 ultrafine powder is 100~600nm.

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