A nano solid-state electrolyte lithium aluminum titanium phosphate and a preparation method and application thereof

Abstract

The application relates to the technical field of lithium ion batteries, in particular to a nano solid-state electrolyte lithium aluminum titanium phosphate and a preparation method and application thereof. The preparation method comprises the following steps: raw materials are prepared according to the stoichiometric ratio of lithium aluminum titanium phosphate, a precipitate is prepared, and the precipitate is washed; the atomic ratio of the raw materials satisfies Li:Al:Ti:P=(1+x):x:(2-x):3, 0<=x<=0.5; water is used as a solvent in the preparation process of the precipitate; the washed precipitate is configured into a suspension liquid by adding water, then the suspension liquid is moved into a sealed pressure container, reacts at a certain temperature for a period of time, then the reacted material is dried to obtain a precursor powder; and the precursor powder is subjected to heat treatment to obtain the solid-state electrolyte lithium aluminum titanium phosphate. The solid-state electrolyte lithium aluminum titanium phosphate obtained by the application has a D50 of less than 200 nm, and can effectively improve the overall performance of a lithium ion battery when applied to the lithium ion battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery, in particular to a kind of nano solid electrolyte lithium aluminum titanium phosphate and preparation method and application. BACKGROUND

[0002] In solid electrolyte, lithium aluminum titanium phosphate Li 1+x Al x Ti 2-x (PO4)3(x=0.3-0.5) (hereinafter referred to as "LATP") has high room temperature ionic conductivity, close to the level of commercial electrolyte and is particularly concerned. The current common method for synthesizing lithium aluminum titanium phosphate mainly includes solid phase sintering method, liquid phase precipitation method, sol-gel method, etc. In these preparation methods, the solid phase sintering method and the precipitation method are simple in process and are more suitable for mass production in industry. In the process of preparing LATP powder by the existing solid phase sintering method, the energy is generally high, the reaction time is long, impurity phases are easily produced, and the particle size of the powder is generally large (> 10 μm); in order to obtain nano-sized LATP powder material, sol-gel method is generally used in the reported data to prepare, which generally needs to use some organic solvents such as ethanol and ethylene glycol, which greatly limits the demand for equipment in the process of process amplification. SUMMARY

[0003] The present application provides a kind of nano solid electrolyte lithium aluminum titanium phosphate and preparation method and application, to solve the problem of large particle size of LATP solid electrolyte prepared by the existing preparation, and the synthesis temperature is too high in the preparation process, which easily leads to the loss of lithium, the problem of excessive energy consumption and complex process.

[0004] The present application provides a kind of preparation method of nano solid electrolyte lithium aluminum titanium phosphate, comprising the following steps:

[0005] Step S1: according to the stoichiometric ratio of lithium aluminum titanium phosphate, the raw materials are configured, the precipitate is prepared by using the raw materials, and the precipitate is washed; wherein the atomic ratio of the raw materials meets: Li: Al: Ti: P = (1+x): x: (2-x): 3, 0≤x≤0.5; water is used as solvent in the preparation of the precipitate; preferably, 0.3≤x≤0.5; more preferably, x=0.3 or 0.4;

[0006] Step S2: the washed precipitate is configured into a suspension after adding water, and then moved into a sealed pressure container, reacted at a certain temperature for a period of time, and then the reacted material is dried to obtain a precursor powder;

[0007] Step S3: the precursor powder is obtained by heat treatment to obtain the solid electrolyte lithium aluminum titanium phosphate.

[0008] In the above scheme, the preparation method of the solid-state electrolyte lithium aluminum titanium phosphate adopts a water-based system, which can reduce the equipment requirements and environmental protection requirements in the industrial scale production process. The preparation method of the present application first uses water as a solvent to prepare a precipitate, and the precipitate is washed. Washing the precipitate can remove excess ions in the precipitate that do not participate in the reaction, which can effectively avoid the influence of these ions on the final form of the subsequent product. Under high temperature and high pressure, the particle reactivity between ions is higher, which makes the effective particle collision more and the raw material mixing more uniform. The preparation method of the present application configures the washed precipitate into a suspension after adding water, and then moves it into a sealed pressure container for reaction at a certain temperature for a period of time, which can effectively control the reaction and crystal growth, so that the initial particle size formed is smaller than that of the particles made by ordinary precipitation method, thereby forming a small size precursor powder. The small size precursor powder is finally heat treated to obtain a solid-state electrolyte lithium aluminum titanium phosphate with a D50 of less than 200 nm. The application of such a solid-state electrolyte lithium aluminum titanium phosphate to a lithium ion battery can effectively improve the overall performance of the lithium ion battery.

[0009] According to the preparation method of the present application, the following steps are included:

[0010] Step S1: an aluminum source, a titanium source and a phosphorus source are added to water to configure a mixed salt solution; an alkaline solution is added dropwise to the mixed salt solution until the pH value is 7-10 to form the precipitate; and the precipitate is washed with water for 1-3 times;

[0011] Step S2: the washed precipitate is mixed uniformly with a lithium ion solution, then water is added to configure the suspension, and then the suspension is moved into a sealed pressure container for reaction at 80-130℃ for 2-12h; and then the reacted material is dried to obtain the precursor powder;

[0012] Step S3: the precursor powder is heat treated to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0013] Specifically, in step S1, the alkaline solution can be selected from ammonium bicarbonate solution, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, ammonia, etc. The pH value can be 7, 7.5, 8, 8.5, 9, 9.5 or 10, etc., and of course can also be other values within the above range, which are not limited herein. The number of washing times can be 1, 2 or 3. In step S2, the temperature of the reaction moved into the sealed pressure vessel can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃ or 130℃, etc., and of course can also be other values within the above range, which are not limited herein, and the time can be 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, etc., and of course can also be other values within the above range, which are not limited herein.

[0014] In the above scheme, in order to reduce the loss of lithium during the preparation of the precipitate, the lithium salt, such as lithium hydroxide, lithium nitrate, lithium acetate, etc., which is soluble in water, is mixed with the precipitate in the form of lithium ion solution and then added to the sealed pressure vessel for hydrothermal reaction.

[0015] According to the preparation method of the present application, the following steps are included:

[0016] Step S1: an aluminum source, a titanium source and a phosphorus source are added to water to configure a mixed salt solution, an alkaline solution is added dropwise to the mixed salt solution until the pH value is 7-10 to form a first precipitate; the first precipitate is put into water, a lithium salt is then added to the water, and then dispersed sufficiently to obtain a second precipitate by suction filtration;

[0017] Step S2: the second precipitate is configured into the suspension by adding water, and then the suspension is moved into a sealed pressure vessel for reaction at 80℃-130℃ for 2h-12h; then the reacted material is dried to obtain the precursor powder;

[0018] Step S3: the precursor powder is obtained by heat treatment to obtain the solid-state electrolyte lithium titanium aluminum phosphate.

[0019] Specifically, in step S1, the alkaline solution can be selected from ammonium bicarbonate solution, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, ammonia, etc. The pH value can be 7, 7.5, 8, 8.5, 9, 9.5 or 10, etc., and of course other values within the above range are also possible, which are not limited herein. The temperature for the reaction in the sealed pressure vessel can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃ or 130℃, etc., and of course other values within the above range are also possible, which are not limited herein. The time can be 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, etc., and of course other values within the above range are also possible, which are not limited herein.

[0020] In the above scheme, the lithium salt which is insoluble or slightly soluble in water is designed. In order to reduce the loss of lithium during the preparation of the first precipitate, the lithium salt which is insoluble or slightly soluble in water (such as lithium carbonate) is mixed with the first precipitate in the form of lithium salt after washing, and then added to the sealed pressure vessel for hydrothermal reaction.

[0021] According to the preparation method of the present application, the aluminum source includes one or more of aluminum nitrate, aluminum chloride, aluminum hydroxide;

[0022] And / or, the titanium source includes one or more of tetrabutyl titanate and titanium tetrachloride;

[0023] And / or, the phosphorus source includes one or more of ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

[0024] According to the preparation method of the present application, the lithium ion solution includes one or more of lithium hydroxide solution, lithium nitrate solution and lithium acetate solution.

[0025] According to the preparation method of the present application, the lithium salt includes lithium carbonate.

[0026] According to the preparation method of the present application, the filling pressure in the sealed pressure vessel is maintained at 0.4-0.6 MPa.

[0027] Alternatively, the filling pressure in the sealed pressure vessel can be maintained at 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa or 0.6 MPa, etc., and of course other values within the above range are also possible, which are not limited herein.

[0028] By limiting the filling pressure in the sealed pressure vessel within a reasonable range, the hydrothermal reaction of the precipitate is facilitated, the reaction and the growth of the crystal can be more effectively controlled, so that the obtained precursor powder has smaller size and more uniform particle distribution, and thus a solid-state electrolyte lithium aluminum titanium phosphate with small size and uniform particle distribution is obtained.

[0029] According to the preparation method, in step S3, the temperature of the heat treatment is 800-950℃, and the time is 1-10h.

[0030] Optionally, in step S3, the temperature of the heat treatment can be 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃ or 950℃, and of course, other values within the above range are also possible, which are not limited herein. The time of the heat treatment can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, and of course, other values within the above range are also possible, which are not limited herein.

[0031] By limiting the temperature and time of the heat treatment within a reasonable range, the internal structure of the solid-state electrolyte lithium aluminum titanium phosphate crystal is controlled, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate has small size and uniform particle distribution.

[0032] The application further provides a nano solid-state electrolyte lithium aluminum titanium phosphate prepared by the above preparation method; the D50 of the solid-state electrolyte lithium aluminum titanium phosphate is less than 200nm.

[0033] The application further provides the solid-state electrolyte lithium aluminum titanium phosphate prepared by the above preparation method or the application of the above solid-state electrolyte lithium aluminum titanium phosphate in lithium ion batteries.

[0034] Specifically, the solid-state electrolyte lithium aluminum titanium phosphate prepared by the above preparation method or the above solid-state electrolyte lithium aluminum titanium phosphate can be applied to the positive and negative electrode materials added into lithium ion batteries, and by forming a coating layer on the surface thereof during the mixing process, the nano size can reduce the thickness of the coating layer, so as to improve the interface problem between the solid-state electrolyte and the positive and negative electrode materials without affecting the battery performance of the positive and negative electrode materials, thereby improving the overall performance of the lithium ion batteries.

[0035] The application provides a nano solid-state electrolyte lithium aluminum titanium phosphate and a preparation method and application thereof, the preparation method adopts a water-based system, and equipment demand and environmental protection demand in an industrial scale production process can be reduced. The preparation method of the application is that: after the precipitate after washing is configured into a suspension liquid and is moved into a sealed pressure container, reaction is carried out at a certain temperature for a period of time, so that the reaction and the growth of the crystal can be effectively controlled, thereby the initial particle size is smaller than that of a particle size prepared by an ordinary precipitation method, and then a small-size precursor powder is obtained. The small-size precursor powder is finally subjected to heat treatment, so that the solid-state electrolyte lithium aluminum titanium phosphate with a D50 of less than 200 nm is obtained, and the solid-state electrolyte lithium aluminum titanium phosphate is applied to a lithium ion battery, so that the electrical performance of the lithium ion battery can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0037] Figure 1 is an XRD pattern of the solid-state electrolyte LATP powder provided in Example 1 of the application;

[0038] Figure 2 is an SEM morphology diagram of the solid-state electrolyte LATP powder provided in Example 1 of the application;

[0039] Figure 3 is an SEM morphology diagram of the solid-state electrolyte LATP powder provided in Example 2 of the application;

[0040] Figure 4 is an SEM morphology diagram of the LATP powder provided in Comparative Example 1 of the application;

[0041] Figure 5 is an SEM morphology diagram of the LATP powder provided in Comparative Example 2 of the application. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the application clearer, the technical solutions in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the application.

[0043] Example 1

[0044] A preparation method of a nano solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0045] Step S1: 10.43 g of aluminum chloride, 84.10 g of titanium tetrachloride, and 90.02 g of ammonium dihydrogen phosphate are added to a certain amount of water to configure a 1L mixed salt solution, 2 mol / L of an ammonium bicarbonate solution is added to the mixed salt solution, the pH is adjusted to 8.0, after white precipitates are formed, stirring is continued for 3 h, then the precipitates are suction-filtered out, and the precipitates are continuously dispersed in water and suction-filtered out again.

[0046] Step S2: a lithium ion solution of 0.1 mol / L is configured by using lithium hydroxide, 4.07 ml of the lithium ion solution is taken, the obtained washed precipitates and the lithium ion solution are mixed, and water is configured to 800 ml of a suspension, the suspension is moved into a 1L sealed pressure container, and reaction is performed at 80°C for 12 h; during the reaction, the filling pressure in the sealed pressure container is maintained at 0.4 MPa-0.6 MPa; after cooling to room temperature, the slurry is taken out, and drying treatment is performed at 130°C to obtain a LATP precursor powder.

[0047] Step S3: the obtained precursor powder is calcined at 850°C for 4 h to obtain a nano solid-state electrolyte LATP powder, and the particle size D50 is approximately 100 nm.

[0048] Attached Figure 1 The XRD pattern of the prepared nano solid-state electrolyte LATP powder is attached Figure 2 The SEM morphology diagram of the prepared nano solid-state electrolyte LATP powder is attached.

[0049] Example 2

[0050] A preparation method of a nano solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0051] Step S1: 16.67 g of aluminum nitrate, 84.10 g of titanium tetrachloride, and 90.02 g of ammonium dihydrogen phosphate are added to a certain amount of water to configure a 1L mixed salt solution, 2 mol / L of an ammonium bicarbonate solution is added to the mixed salt solution, the pH is adjusted to 8.0, after white precipitates are formed, stirring is continued for 3 h, then the precipitates are suction-filtered out, and the precipitates are continuously dispersed in water and suction-filtered out again.

[0052] Step S2: the obtained second precipitates are configured into 800 ml of a suspension by adding water, the suspension is moved into a 1L sealed pressure container, and reaction is performed at 100°C for 6 h; during the reaction, the filling pressure in the sealed pressure container is maintained at 0.4 MPa-0.6 MPa; then after cooling to room temperature, the slurry is taken out, and drying treatment is performed at 100°C to obtain a LATP precursor powder;

[0053] Step S3: calcining the obtained precursor powder at 900℃ for 4h to obtain the nano solid-state electrolyte LATP powder, with a particle size D50≈110nm.

[0054] Figure 2 is a SEM image of the nano solid-state electrolyte LATP powder prepared in Example 1. Figure 3 Figure 3 is a SEM image of the nano solid-state electrolyte LATP powder prepared in Example 2.

[0055] Example 3

[0056] A method for preparing a nano solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0057] Step S1: 6.1g of aluminum hydroxide, 84.10g of titanium tetrachloride, and 129.10g of phosphoric acid diammonium hydrogen are added to a certain amount of water to prepare a mixed salt solution of 1L. A 2mol / L ammonium bicarbonate solution is added to the mixed salt solution, and the pH is adjusted to 8.0. After the formation of white precipitate, stirring is continued for 3h, and then the precipitate is suction filtered out and dispersed in water again for suction filtration.

[0058] Step S2: a lithium ion solution of 0.1mol / L is prepared by using lithium hydroxide. 4.07ml of the lithium ion solution is taken, and the obtained washed precipitate and lithium ion solution are mixed and water is added to prepare a suspension of 800mL. The suspension is moved into a 1L sealed pressure container, and reaction is carried out at 80℃ for 12h. During the reaction, the filling pressure in the sealed pressure container is maintained at 0.4MPa-0.6Mpa. After cooling to room temperature, the slurry is taken out and dried at 120℃ to obtain a LATP precursor powder.

[0059] Step 3: the obtained precursor powder is calcined at 900℃ for 4h to obtain the nano solid-state electrolyte LATP powder, with a particle size D50≈110nm.

[0060] Example 4

[0061] A method for preparing a nano solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0062] Step S1: 6.1g of aluminum hydroxide, 84.10g of titanium tetrachloride, and 129.10g of phosphoric acid diammonium hydrogen are added to a certain amount of water to prepare a mixed salt solution of 1L. A 2mol / L ammonium bicarbonate solution is added to the mixed salt solution, and the pH is adjusted to 8.0. After the formation of white precipitate, stirring is continued for 3h, and then the precipitate is suction filtered out and dispersed in water again for suction filtration.

[0063] Step S2: 0.1 mol / L lithium ion solution was prepared by using lithium hydroxide, 4.07 ml of the lithium ion solution was taken, the obtained washed precipitate mixed lithium ion solution was prepared into 800 ml of a suspension by adding water, and the suspension was moved into a 1 L sealed pressure container, reacted at 80°C for 6 h, during the reaction, the filling pressure in the sealed pressure container was maintained at 0.4-0.6 MPa, the slurry was taken out after cooling to room temperature, and the slurry was dried at 100°C to obtain a LATP precursor powder;

[0064] Step 3: the obtained precursor powder was calcined at 900°C for 4 h to obtain a nano solid-state electrolyte LATP powder, and the particle size D50 was about 150 nm.

[0065] Example 5

[0066] A preparation method of a nano solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0067] Step S1: 10.43 g of aluminum chloride, 84.10 g of titanium tetrachloride, and 90.02 g of ammonium dihydrogen phosphate were added to a certain amount of water to prepare a 1 L mixed salt solution, 2 mol / L ammonium bicarbonate solution was added to the mixed salt solution, the pH was adjusted to 8.0, a white precipitate was formed, stirring was continued for 3 h, and then the precipitate was suction filtered, and the precipitate was dispersed in water again and suction filtered.

[0068] Step S2: 0.1 mol / L lithium ion solution was prepared by using lithium hydroxide, 4.07 ml of the lithium ion solution was taken, the obtained washed precipitate mixed lithium ion solution was prepared into 800 ml of a suspension by adding water, and the suspension was moved into a 1 L sealed pressure container, reacted at 80°C for 6 h, during the reaction, the filling pressure in the sealed pressure container was maintained at 0.4-0.6 MPa, the slurry was taken out after cooling to room temperature, and the slurry was dried at 100°C to obtain a LATP precursor powder;

[0069] Step S3: the obtained precursor powder was calcined at 950°C for 4 h to obtain a nano solid-state electrolyte LATP powder, and the powder particle size D50 was about 180 nm.

[0070] Example 6

[0071] A preparation method of a nano solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0072] Step S1: 10.43 g of aluminum chloride, 84.10 g of titanium tetrachloride, and 90.02 g of ammonium dihydrogen phosphate were added to a certain amount of water to prepare a mixed salt solution of 1 L. A 2 mol / L ammonium bicarbonate solution was added to the mixed salt solution, and the pH was adjusted to 7.0 to form white precipitates. The stirring was continued for 3 h, and then the precipitates were suction-filtered and dispersed in water again to suction-filter the precipitates.

[0073] Step S2: A lithium ion solution of 0.05 mol / L was prepared using lithium hydroxide. 8.14 ml of the lithium ion solution was taken, and the obtained washed precipitates were mixed with the lithium ion solution to prepare a suspension of 800 ml. The suspension was transferred into a 1 L sealed pressure container, and reacted at 100°C for 12 h. During the reaction, the filling pressure in the sealed pressure container was maintained at 0.4-0.6 MPa. After cooling to room temperature, the slurry was taken out, and dried at 130°C to obtain a LATP precursor powder.

[0074] Step S3: The obtained precursor powder was calcined at 900°C for 4 h to obtain a nano solid-state electrolyte LATP powder. The particle size of the powder was D50≈130 nm.

[0075] Example 7

[0076] A method for preparing a nano solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0077] Step S1: 10.43 g of aluminum chloride, 84.10 g of titanium tetrachloride, and 90.02 g of ammonium dihydrogen phosphate were added to a certain amount of water to prepare a mixed salt solution of 1 L. A 2 mol / L ammonium bicarbonate solution was added to the mixed salt solution, and the pH was adjusted to 7.0 to form white precipitates. The stirring was continued for 3 h, and then the precipitates were suction-filtered and dispersed in water again to suction-filter the precipitates.

[0078] Step S2: A lithium ion solution of 0.05 mol / L was prepared using lithium hydroxide. 8.14 ml of the lithium ion solution was taken, and the obtained washed precipitates were mixed with the lithium ion solution to prepare a suspension of 800 ml. The suspension was transferred into a 1 L sealed pressure container, and reacted at 100°C for 12 h. During the reaction, the filling pressure in the sealed pressure container was maintained at 0.4-0.6 MPa. After cooling to room temperature, the slurry was taken out, and dried at 130°C to obtain a LATP precursor powder.

[0079] Step S3: The obtained precursor powder was calcined at 900°C for 4 h to obtain a nano solid-state electrolyte LATP powder. The particle size of the powder was D50≈130 nm.

[0080] Comparative Example 1

[0081] A preparation method of a solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0082] Step S1: 6.1 g of aluminum hydroxide, 84.10 g of titanium tetrachloride, and 129.10 g of phosphoric acid diammonium hydrogen are added into a certain amount of water to prepare a mixed salt solution of 1 L, 2 mol / L of an ammonium bicarbonate solution is added into the mixed salt solution, the pH is adjusted to 8.0, and after white precipitates are formed, stirring is continued for 3 h, and then the precipitates are suction-filtered out and are dispersed in water again to suction-filter out the precipitates.

[0083] Step S2: 0.1 mol / L of a lithium ion solution is prepared by using lithium hydroxide, 4.07 ml of the lithium ion solution is taken, the obtained washed precipitates are mixed with the lithium ion solution, and water is added to prepare a suspension of 800 ml, and the suspension is dried at 120 DEG C to obtain a LATP precursor powder.

[0084] Step S3: the obtained precursor powder is calcined at 900 DEG C for 4 h to obtain a LATP powder, and the particle size of the obtained powder is D50≈1 mu m.

[0085] The SEM morphology of the prepared LATP powder is shown in the following figure. Figure 4

[0086] Comparative Example 2

[0087] A preparation method of a solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0088] Step S1: 6.1 g of aluminum hydroxide, 84.10 g of titanium tetrachloride, and 129.10 g of phosphoric acid diammonium hydrogen are added into a certain amount of water to prepare a mixed salt solution of 1 L, 2 mol / L of an ammonium bicarbonate solution is added into the mixed salt solution, the pH is adjusted to 8.0, and after white precipitates are formed, stirring is continued for 3 h, and then the precipitates are suction-filtered out and are dispersed in water again to suction-filter out the precipitates.

[0089] Step S2: the obtained precursor powder is calcined at 900 DEG C for 4 h to obtain a LATP powder. The particle size of the obtained LATP powder is seriously agglomerated, and the secondary particle size is >20 mu m.

[0090] The SEM morphology of the prepared LATP powder is shown in the following figure. Figure 5

[0091] ​​As can be seen from the experimental results of the above examples, the nano solid electrolyte LATP with a particle size of <200 nm can be obtained by using the preparation method of the present application. As can be seen from the comparative experimental results of Example 3 and Comparative Example 1, the hydrothermal treatment process in step S2 has an important influence on the particle size of the final solid electrolyte LATP of the present application. The particle size of the solid electrolyte LATP obtained without the hydrothermal treatment process is in the micron level, and the particle size is large. As can be seen from the comparative experimental results of Example 3 and Comparative Example 2, the washing of the precipitate in step S1 also has an important influence on the particle size of the final solid electrolyte LATP of the present application. The particle agglomeration of the solid electrolyte LATP obtained without washing the precipitate is serious, the particle size is in the micron level, and the particle size is large.

[0092] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a nanosolid-state electrolyte, lithium aluminum titanium phosphate, characterized by, Comprising the following steps: Step S1: configuring raw materials according to the stoichiometric ratio of lithium aluminum titanium phosphate, using the raw materials to prepare a precipitate, and washing the precipitate; wherein the atomic ratio of the raw materials satisfies: Li:Al:Ti:P=(1+x):x:(2-x):3, 0≤x≤0.5; water is used as a solvent during preparation of the precipitate; Step S2: after the washed precipitate is configured into a suspension liquid with water, it is moved into a sealed pressure container, reacted at a certain temperature for a period of time, and then the reacted material is dried to obtain a precursor powder; Step S3: the precursor powder is obtained by heat treatment to obtain the solid-state electrolyte lithium aluminum titanium phosphate; Wherein, Step S1: aluminum source, titanium source, and phosphorus source are added to water to configure a mixed salt solution; an alkaline solution is added dropwise to the mixed salt solution until the pH value is 7-10 to form the precipitate; the precipitate is washed with water for 1-3 times; Step S2: the washed precipitate is mixed uniformly with a lithium ion solution, then water is added to configure the suspension liquid, and then the suspension liquid is moved into a sealed pressure container and reacted at 80-130°C for 2-12 hours; then the reacted material is dried to obtain the precursor powder; the lithium ion solution includes one or more of lithium hydroxide solution, lithium nitrate solution, and lithium acetate solution; Or, Step S1: aluminum source, titanium source, and phosphorus source are added to water to configure a mixed salt solution, an alkaline solution is added dropwise to the mixed salt solution until the pH value is 7-10 to form a first precipitate; the first precipitate is placed in water, lithium salt is then added to the water, and then dispersed thoroughly to obtain a second precipitate; Step S2: the second precipitate is configured into the suspension liquid, and then the suspension liquid is moved into a sealed pressure container and reacted at 80-130°C for 2-12 hours; then the reacted material is dried to obtain the precursor powder; the lithium salt includes lithium carbonate; Wherein, The aluminum source includes one or more of aluminum nitrate, aluminum chloride, and aluminum hydroxide; And / or, the titanium source includes one or more of tetrabutyl titanate and titanium tetrachloride; And / or, the phosphorus source includes one or more of ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

2. The production method according to claim 1, characterized by, The filling pressure in the sealed pressure container is maintained at 0.4-0.6 MPa.

3. The preparation method according to claim 1, characterized in that, In step S3, the temperature of the heat treatment is 800-950°C, and the time is 1-10 hours.

4. A nanosolid electrolyte lithium aluminum titanium phosphate characterized in that, Prepared by the preparation method of any one of claims 1-3; the D50 of the solid-state electrolyte lithium aluminum titanium phosphate is less than 200 nm.

5. Application of the solid-state electrolyte lithium aluminum titanium phosphate prepared by the preparation method of any one of claims 1-3 or the solid-state electrolyte lithium aluminum titanium phosphate of claim 4 in a lithium ion battery.

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