Inorganic solid electrolyte material and preparation method and application thereof
By using amino-containing silane coupling agents and the sol-gel method to prepare inorganic solid electrolyte seed crystals, combined with a high-temperature solid-state method, the problems of purity and conductivity of inorganic solid electrolytes were solved, and high-performance inorganic solid electrolyte materials were prepared.
Patent Information
- Application Number
- CN202511008372.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-11-11
AI Technical Summary
Existing inorganic solid electrolytes have low phase purity, are prone to particle agglomeration, and have low ionic conductivity. The preparation method has a significant impact on the phase, grain size, and grain boundary resistance of the product.
An amino-containing silane coupling agent was used as a complexing agent to prepare inorganic solid electrolyte seed crystals using the sol-gel method. The seed crystals were then mixed with inorganic solid electrolyte raw materials using a high-temperature solid-phase method, and crystal growth was induced by using the seed crystals as nuclei, thereby improving sintering uniformity and crystallization performance.
This improved the phase purity and ionic conductivity of the inorganic solid electrolyte, ensured particle consistency, enhanced interface matching with the target crystal, and improved the overall performance of the electrolyte.
Smart Images
Figure CN120922828A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of methods or apparatus for directly converting chemical energy into electrical energy, and more particularly to an inorganic solid electrolyte material, its preparation method, and its application. Background Technology
[0002] Compared to traditional liquid electrolytes, solid-state electrolytes offer higher energy density, better electrochemical stability, and a wider electrochemical window, along with superior mechanical properties, effectively improving the safety performance of lithium-ion batteries. Solid-state electrolytes are mainly classified into polymer solid-state electrolytes and inorganic solid-state electrolytes based on their chemical composition. While polymer solid-state electrolytes exhibit good ductility, they suffer from low ionic conductivity, a narrow temperature range, and poor mechanical structural stability. In contrast, inorganic solid-state electrolytes not only possess high ionic conductivity but also maintain good structural stability within a temperature range of -70℃ to 500℃, making them a more promising type of solid-state electrolyte. Currently, the main methods for preparing inorganic solid-state electrolytes include high-temperature solid-state methods, sol-gel methods, chemical co-precipitation methods, and hydrothermal methods. Different preparation methods and process conditions significantly influence the phase composition, grain size, grain boundary resistance, and crystallinity of the product. Existing conventional preparation methods often result in inorganic solid-state electrolytes with low phase purity, easy particle agglomeration, and low ionic conductivity. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an inorganic solid electrolyte material, its preparation method, and its application.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] In a first aspect, the present invention provides a method for preparing an inorganic solid electrolyte material, the method comprising the following steps:
[0006] S1. Using an amino-containing silane coupling agent as a complexing agent for metal ions, an inorganic solid electrolyte A is prepared by the sol-gel method, and then seed crystals are obtained through crystallization.
[0007] S2. The seed crystals obtained in S1 are mixed evenly with the raw materials of inorganic solid electrolyte B to obtain a precursor, and then the inorganic solid electrolyte material is prepared by high temperature solid phase method.
[0008] The inorganic solid electrolyte A has the same chemical formula as the inorganic solid electrolyte B;
[0009] The inorganic solid electrolyte material is any one of oxide solid electrolytes.
[0010] The preparation method of this invention first uses an amino-containing silane coupling agent as a complexing agent for metal ions, and combines it with the sol-gel method to prepare seed crystals of inorganic solid electrolyte. The amino-containing silane coupling agent can co-hydrolyze with the metal salt in the inorganic solid electrolyte raw material, and the amino group can also coordinate with the metal ions to inhibit the excessive growth of particles. At the same time, a certain amount of active amino groups are retained on the surface of the formed seed crystal to enhance the interface matching with the target crystal. During the high-temperature solid-state preparation of inorganic solid electrolyte, the seed crystal acts as a nucleus to induce crystal growth, reduce the nucleation energy of the inorganic solid electrolyte raw material in the high-temperature molten state, thereby improving the sintering uniformity and the crystallization performance of the inorganic solid electrolyte, and further improving the phase purity, ionic conductivity and particle uniformity of the inorganic solid electrolyte.
[0011] This invention does not impose any particular limitation on amino-containing silane coupling agents, as long as they can achieve the purpose of this invention. For example, amino-containing silane coupling agents can be at least one of 3-aminopropyltriethoxysilane (CAS No.: 919-30-2), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CAS No.: 1760-24-3), N-phenyl-γ-aminopropyltrimethoxysilane, bis-(3-triethoxysilylpropyl)amine, bis-(3-trimethoxysilylpropyl)amine, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltrimethoxysilane.
[0012] Step S1 in the above preparation method specifically involves: dissolving the raw material (soluble metal salt) of the inorganic solid electrolyte A in a solvent, and adjusting the pH of the solution to 4.5–5.5 (for example, it can be adjusted using organic acids such as citric acid, malic acid, formic acid, acetic acid, oxalic acid, succinic acid, propionic acid, butyric acid, benzoic acid, fatty acids, and amino acids; the specific pH values can be 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, and 5.4). The range of values in 5.5 or both is used; at 60-100°C (preferably around 80°C), the metal ions are complexed with the amino-containing silane coupling agent to form a sol, which is then heated until the water is completely evaporated, so that the sol is converted into a gel; the gel is calcined at 400-600°C for 2-8 hours to remove organic matter and other excess ions; finally, the obtained product is ground and then crystallized at 700-1000°C for 2-8 hours to obtain seed crystals.
[0013] Step S2 in the above preparation method is specifically as follows: the seed crystals are mixed with the raw materials of inorganic solid electrolyte B, and the mixed material is calcined (the calcination temperature and time can be selected according to the type of inorganic solid electrolyte) and coarsely crushed and finely crushed to obtain inorganic solid electrolyte material.
[0014] Specifically, a mixer can be used to mix for 1 to 12 hours. Mixers include, but are not limited to, planetary ball mills, high-energy ball mills, drum ball mills, three-dimensional mixers, blade mixers, twin-screw extruders, double-cone mixers, vertical mixers, horizontal dry ball mills, octagonal ball mills, air jet mills, fluidized beds, single-cone twin-screw mixers, and vacuum mixing tanks.
[0015] The calcination process includes a staged heating process, a constant temperature process, and a cooling process. The heating rate during the staged heating process is 1–10 °C / min. The atmosphere during the calcination process includes at least one of air, argon, nitrogen, and oxygen. During the constant temperature process, each constant temperature process lasts no less than 2 hours. The sintering equipment includes, but is not limited to, box furnaces, tube furnaces, roller kilns, and rotary kilns.
[0016] Coarse crushing equipment includes, but is not limited to, jaw crushers, cone crushers, impact crushers, hammer crushers, and roller crushers; fine crushing equipment includes, but is not limited to, flat air jet mills, fluidized bed air jet mills, circulating air jet mills, impact crushers, expansion crushers, ball mills, high-speed rotary ball mills, and high-speed rotary impact mills.
[0017] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the purity of the seed crystal is ≥80%, preferably 83% to 91%; for example, it can be any or both of the following ranges: 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, and 95%. The purity of the seed crystal affects the phase purity of the inorganic solid electrolyte material. The higher the purity of the seed crystal, the fewer impurities it contains, which better avoids impurities potentially becoming heterogeneous nucleation sites, leading to crystal growth deviating from the expected direction and subsequent abnormal crystal orientation.
[0018] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the crystallization treatment temperature is 700–1000℃ (for example, any or both of 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, and 1000℃) and the time is 2–8h (for example, any or both of 2h, 3h, 4h, 5h, 6h, 7h, and 8h). By controlling the high crystallization treatment temperature within the above range, not only can the sintering of the raw materials be better ensured to improve the purity of the synthesized phase, but also excessive Li volatilization can be effectively avoided, which would lead to a decrease in the ionic conductivity of the inorganic solid electrolyte material.
[0019] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the atmosphere of the crystallization treatment is air or an inert gas (e.g., nitrogen, argon, etc.).
[0020] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the mass percentage of the seed crystal relative to the raw material of the inorganic solid electrolyte B is ≥0.1%. For example, the mass percentage of the seed crystal relative to the raw material of the inorganic solid electrolyte B can be any one or any two of the following values: 0.1%, 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 11%, and 12%.
[0021] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the seed crystals account for 0.5% to 10% of the mass percentage of the raw material of the inorganic solid electrolyte B. Studies have found that as the amount of seed crystals added increases, the raw material of the inorganic solid electrolyte B has more nucleation sites in the high-temperature molten state, thereby reducing the nucleation stage during sintering and shortening the sintering cycle; however, a large number of nucleation sites leads to a smaller primary particle size and more grain boundaries in the inorganic solid electrolyte, which in turn reduces the ionic conductivity of the inorganic solid electrolyte material.
[0022] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the molar ratio of the amino-containing silane coupling agent to the metal ions is (1-5):(0.5-1). For example, the molar fraction of the amino-containing silane coupling agent can be any one or both of the following: 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, and 5 parts; the molar fraction of the metal ions can be any one or both of the following: 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part. Studies have found that by controlling the molar ratio of the amino-containing silane coupling agent to the metal ions within the above range, it is possible not only to fully complex with the metal ions, avoiding premature hydrolysis or precipitation of some metal ions, and thus forming a uniform sol to reduce component segregation or impurity phases in the product; it is also possible to avoid excessive residual amino-containing silane coupling agent leading to organic residues, reducing the burden of subsequent heat treatment and abnormal pore structure.
[0023] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the average particle size of the inorganic solid electrolyte A is 0.05–0.3 μm. For example, the average particle size of the inorganic solid electrolyte A can be any or any combination of 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.15 μm, 0.18 μm, 0.2 μm, 0.25 μm, and 0.3 μm.
[0024] In a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the average particle size of the seed crystals is 0.05–0.3 μm. For example, the average particle size of the seed crystals can be any or both of the following: 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.15 μm, 0.18 μm, 0.2 μm, 0.25 μm, and 0.3 μm. By controlling the average particle size of the seed crystals within the above range, it is possible not only to better prevent the seed crystals from rapidly turning into a molten state and losing their template function during high-temperature solid-phase reactions, but also to maintain a large number of surface active sites on their surface to provide sufficient nucleation driving force, thereby better promoting the improvement of the phase purity of the inorganic solid electrolyte material.
[0025] As a preferred embodiment of the preparation method of the inorganic solid electrolyte material of the present invention, the oxide solid electrolyte includes at least one of garnet-type solid electrolyte material, NASCION-type solid electrolyte, LISCION-type solid electrolyte, and perovskite-type solid electrolyte.
[0026] Secondly, the present invention provides an inorganic solid electrolyte material prepared by the above-described method. Preferably, the primary particle size range of the inorganic solid electrolyte material is 0.1–10 μm.
[0027] Thirdly, the present invention provides an application of the above-mentioned inorganic solid electrolyte material in the preparation of all-solid-state lithium-ion batteries or all-solid-state sodium-ion batteries.
[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0029] The preparation method of this invention first uses an amino-containing silane coupling agent as a complexing agent for metal ions, and combines it with the sol-gel method to prepare seed crystals of inorganic solid electrolyte. The amino-containing silane coupling agent can co-hydrolyze with the metal salt in the inorganic solid electrolyte raw material, and the amino group can also coordinate with the metal ions to inhibit the excessive growth of particles. At the same time, a certain amount of active amino groups are retained on the surface of the formed seed crystal to enhance the interface matching with the target crystal. During the high-temperature solid-state preparation of inorganic solid electrolyte, the seed crystal acts as a nucleus to induce crystal growth, reduce the nucleation energy of the inorganic solid electrolyte raw material in the high-temperature molten state, thereby improving the sintering uniformity and the crystallization performance of the inorganic solid electrolyte, and further improving the phase purity, ionic conductivity and particle uniformity of the inorganic solid electrolyte. Attached Figure Description
[0030] Figure 1 SEM image of the inorganic solid electrolyte material prepared in Comparative Example 3;
[0031] Figure 2This is a SEM image of the inorganic solid electrolyte material prepared in Example 1. Detailed Implementation
[0032] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0033] Unless otherwise specified, all other materials and reagents used in the examples are commercially available.
[0034] Test methods and equipment
[0035] 1. Phase purity test: Test the XRD diffraction pattern of the inorganic solid electrolyte material and compare the intensity of the diffraction peaks of the main phase and the impurity phase.
[0036] Phase purity = Main phase diffraction peak intensity / (Main phase diffraction peak intensity + Impurity phase diffraction peak intensity) × 100%.
[0037] XRD diffraction peak data of inorganic solid electrolyte materials were compared with standard PDF cards. Diffraction peaks conforming to the standard cards were identified as target material diffraction peaks. Target diffraction peaks were defined as the main phase, and non-target diffraction peaks as impurity phases. The crystallinity of the main phase and impurity phases was obtained by fitting the data to the corresponding diffraction peak intensities.
[0038] 2. Primary particle size (D50) test: The inorganic solid electrolyte material was tested using a Malvern 3000 particle size analyzer to obtain the primary particle size.
[0039] 3. Ionic Conductivity Test: An inorganic solid electrolyte material is fabricated into an electrolyte sheet, and silver is plated on both sides of the electrolyte sheet. The impedance value of the electrolyte sheet is then measured using an electrochemical workstation. Ionic conductivity σ = D / RS, where D is the thickness of the electrolyte sheet (cm); R is the impedance value of the electrolyte sheet measured by the electrochemical workstation (Ω); and S is the area of one side of the electrolyte sheet (cm²). 2 .
[0040] Example 1
[0041] <Preparation of Seed Crystals>
[0042] According to Li 1.5 Al 0.5 Ti 1.5 P3O 12The stoichiometric ratios of the elements were as follows: aluminum source (aluminum nitrate), titanium source (tetrabutyl titanate), lithium source (lithium carbonate), and phosphorus source (ammonium dihydrogen phosphate). First, the titanium source was added to a mixed alcoholic solution of citric acid and a complexing agent (3-aminopropyltriethoxysilane) and stirred at 80°C for 1 hour to allow the titanium source to fully hydrolyze and form a homogeneous colorless solution. Then, the phosphorus source, lithium source, and aluminum source were added sequentially, and the mixture was stirred at 80°C for another 4 hours to form a milky white sol. The sol was kept at 120°C until the alcohol evaporated completely, allowing the sol to transform into a gel. The gel was then calcined at 500°C for 4 hours to remove organic matter and excess ions. Finally, the obtained product was ground and kept at 800°C for 6 hours in a nitrogen atmosphere (crystallization treatment) to obtain seed crystals (average particle size of 0.05 μm).
[0043] Preparation of Inorganic Solid Electrolyte Materials
[0044] According to Li 1.5 Al 0.5 Ti 1.5 P3O 12 The stoichiometric ratio of each element is determined by weighing aluminum source (alumina), titanium source (titanium oxide), lithium source (lithium carbonate), and phosphorus source (ammonium dihydrogen phosphate) and mixing them to obtain a mixed raw material; then the above seed crystals are mixed with the mixed raw material at a mass ratio of 0.5:100 to obtain a precursor; then the precursor is calcined at 850℃ for 5 hours and crushed to obtain an inorganic solid electrolyte material.
[0045] Example 2
[0046] Except for the fact that the mass ratio of seed crystals to mixed raw materials in the <Preparation of Inorganic Solid Electrolyte Materials> is 0.1:100, the rest is the same as in Example 1.
[0047] Example 3
[0048] Except for the fact that the mass ratio of seed crystals to mixed raw materials is 2:100 in the <Preparation of Inorganic Solid Electrolyte Materials>, the rest is the same as in Example 1.
[0049] Example 4
[0050] Except for the fact that the mass ratio of seed crystals to mixed raw materials is 5:100 in the <Preparation of Inorganic Solid Electrolyte Materials>, the rest is the same as in Example 1.
[0051] Example 5
[0052] Except for the fact that the mass ratio of seed crystals to mixed raw materials is 8:100 in the <Preparation of Inorganic Solid Electrolyte Materials>, the rest is the same as in Example 1.
[0053] Example 6
[0054] Except for the complexing agent in <Preparation of Seed Crystals> being γ-aminopropyltrimethoxysilane, the rest is the same as in Example 1.
[0055] Example 7
[0056] Except for the average seed size of 0.1 μm in <Preparation of Seed Crystals>, it is the same as in Example 1.
[0057] Example 8
[0058] Except for the average seed size of 0.3 μm in <Preparation of Seed Crystals>, it is the same as in Example 1.
[0059] Example 9
[0060] Except for the crystallization temperature of 700°C and the time of 8h in the <Preparation of Seed Crystals>, the rest is the same as in Example 1.
[0061] Example 10
[0062] Except for the crystallization temperature of 900°C and the time of 4h in the <Preparation of Seed Crystals>, the rest is the same as in Example 1.
[0063] Example 11
[0064] <Preparation of Seed Crystals>
[0065] According to Li 6.4 La3Zr 1.6 Ta 0.4 O 12 The stoichiometric ratios of the elements in the solution were as follows: lanthanum source (lanthanum nitrate), zirconium source (zirconium oxynitrate), lithium source (lithium carbonate), and tantalum source (tantalum ethoxide). First, the zirconium source was added to a mixed alcoholic solution of citric acid and a complexing agent (3-aminopropyltriethoxysilane), and stirred at 80°C for 1 hour to allow complete hydrolysis of the zirconium source into a homogeneous, colorless solution. Then, the lanthanum, lithium, and tantalum sources were added sequentially, and stirring continued at 120°C for 4 hours to form a milky white sol. The sol was maintained at 120°C until the alcohol evaporated completely, transforming the sol into a gel. The gel was then calcined at 500°C for 4 hours to remove organic matter and excess ions. Finally, the resulting product was ground and kept in air at 950°C for 12 hours (crystallization treatment) to obtain seed crystals.
[0066] Preparation of Inorganic Solid Electrolyte Materials
[0067] According to Li 6.4 La3Zr 1.6 Ta 0.4 O 12The stoichiometric ratio of each element is determined by weighing lithium source (lithium hydroxide monohydrate), lanthanum source (lanthanum trioxide), zirconium source (zirconium dioxide), and tantalum source (tantalum pentoxide) to obtain a mixed raw material. The above seed crystals are then mixed with the mixed raw material at a mass ratio of 0.5:100 to obtain a precursor. The precursor is then calcined at 950℃ for 12 hours and crushed to obtain an inorganic solid electrolyte material.
[0068] Comparative Example 1
[0069] Except for the absence of a complexing agent in the <Preparation of Seed Crystals> section, the rest is the same as in Example 1.
[0070] Comparative Example 2
[0071] Except for the use of tetraethyl orthosilicate as the complexing agent in <Preparation of Seed Crystals>, the rest is the same as in Example 5.
[0072] Comparative Example 3
[0073] Except for the fact that the mass ratio of seed crystals to mixed raw materials is 0:100 in the <Preparation of Inorganic Solid Electrolyte Materials>, the rest is the same as in Example 1.
[0074] Table 1
[0075]
[0076] According to the data in Table 1, the phase purity of the inorganic solid electrolyte materials in Examples 1 to 11 is ≥90% and the ionic conductivity is ≥2.7×10⁻⁶. -4 S / cm indicates that the inorganic solid electrolyte material prepared by the method of this invention possesses both high phase purity and high ionic conductivity. Meanwhile, according to... Figure 1 and Figure 2 It can be seen that, under the same conditions, the inorganic solid electrolyte material without added crystal seeds has irregularly shaped particles with uneven particle size; while the inorganic solid electrolyte material with added crystal seeds has more rounded particles with more uniform particle size, indicating that the inorganic solid electrolyte material prepared by the method of the present invention has better particle consistency.
[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing an inorganic solid electrolyte material, characterized in that, Includes the following steps: S1. Using an amino-containing silane coupling agent as a complexing agent for metal ions, an inorganic solid electrolyte A is prepared by the sol-gel method, and then seed crystals are obtained through crystallization. S2. The seed crystals obtained in S1 are mixed evenly with the raw materials of inorganic solid electrolyte B to obtain a precursor, and then the inorganic solid electrolyte material is prepared by high temperature solid phase method. The inorganic solid electrolyte A has the same chemical formula as the inorganic solid electrolyte B; The inorganic solid electrolyte material is any one of oxide solid electrolytes.
2. The preparation method according to claim 1, characterized in that, The crystallization treatment is carried out at a temperature of 700–1000°C for 2–8 hours; and / or the atmosphere for the crystallization treatment is air or an inert gas.
3. The preparation method according to claim 1, characterized in that, The seed crystal has a mass percentage of ≥0.1% relative to the raw material of inorganic solid electrolyte B.
4. The preparation method according to claim 3, characterized in that, The seed crystal has a mass percentage of 0.5% to 10% relative to the raw material of inorganic solid electrolyte B.
5. The preparation method according to claim 1, characterized in that, The molar ratio of the amino-containing silane coupling agent to the metal ions is (1-5):(0.5-1).
6. The preparation method according to claim 1, characterized in that, The average particle size of the inorganic solid electrolyte A is 0.05–0.3 μm.
7. The preparation method according to claim 1, characterized in that, The average particle size of the seed crystals is 0.05–0.3 μm.
8. The preparation method according to claim 1, characterized in that, The oxide solid electrolyte includes at least one of garnet-type solid electrolyte materials, NASCION-type solid electrolyte, LISCION-type solid electrolyte, and perovskite-type solid electrolyte.
9. The inorganic solid electrolyte material prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the inorganic solid electrolyte material according to claim 9 in the preparation of all-solid-state lithium-ion batteries or all-solid-state sodium-ion batteries.