A method for preparing low-cost sodium titanate negative material from titanyl sulfate solution
Low-cost sodium titanate anode materials were prepared by using a titanium oxysulfate solution, which eliminated the calcination and impurity removal steps. Metatitanic acid was directly used as the titanium source and mixed with sodium source for calcination, which solved the problem of high production cost of sodium titanate anode materials and realized high-performance sodium titanate anode materials.
Patent Information
- Application Number
- CN202411427162.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2044-10-14
AI Technical Summary
The high production cost of existing sodium titanate anode materials limits their application. Existing synthesis methods, such as hydrothermal and sol-gel methods, are too expensive and difficult to scale up for production.
A method for preparing low-cost sodium titanate anode materials using a titanium oxysulfate solution includes preheating of the bottom solution, hydrolysis, preparation of metatitanic acid, and calcination. This method omits the calcination, surface treatment, and impurity removal steps from metatitanic acid to titanium dioxide, and directly uses metatitanic acid as the titanium source and mixes it with sodium source for calcination.
Production costs were reduced and production efficiency was improved. The prepared sodium titanate anode material has a specific capacity of over 82 mAh/g at 2000 mA/g and a capacity retention rate of over 78.4% after 1000 cycles, demonstrating excellent performance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of sodium-ion battery technology, and particularly relates to a method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution. Background Technology
[0002] With the increasing global demand for renewable energy, energy storage technology has become crucial for achieving energy transition and ensuring energy security. Among various energy storage technologies, sodium-ion batteries are gradually becoming a powerful complement to lithium-ion batteries, especially in the field of large-scale energy storage, due to their abundant resources, low cost, and potential high energy density. However, the application of graphite, a widely used anode material in lithium-ion batteries, is limited by issues such as ion size mismatch and interlayer spacing. Therefore, researchers are exploring other types of anode materials, among which sodium titanate has received widespread attention and research in recent years due to its environmental friendliness and safety, making it highly suitable for large-scale energy storage.
[0003] However, the synthesis methods of sodium titanate materials reported so far are mostly limited to hydrothermal methods and sol-gel methods. In addition, the raw materials are mostly titanium metal and tetrabutyl titanate, which leads to high production costs and the inability to scale up production, thus restricting the commercialization of sodium titanate materials.
[0004] Existing methods for preparing sodium titanate anode materials generally use titanium metal, tetrabutyl titanate, titanium dioxide, and other substances as titanium sources, resulting in high production costs and limiting the application of sodium titanate anode materials. How to prepare low-cost sodium titanate anode materials has become an urgent technical problem to be solved. Summary of the Invention
[0005] To address the high production cost of existing sodium titanate anode materials, this invention provides a method for preparing low-cost sodium titanate anode materials using a titanium oxysulfate solution.
[0006] This invention discloses a method for preparing low-cost sodium titanate anode materials from a titanium oxysulfate solution. The preparation method includes the following steps:
[0007] S1. Preheating of the base solution: Take an appropriate amount of deionized water into the reactor and preheat it to 80℃-110℃;
[0008] S2. Hydrolysis: Under stirring, the titanium oxysulfate solution is added to the reactor at a constant rate, and the temperature of the system inside the reactor is kept constant. The hydrolysis reaction ends when the feeding is finished.
[0009] S3. Preparation of metatitanic acid: Cool the hydrolyzed slurry to room temperature, wash it with water, and dry it to obtain metatitanic acid.
[0010] S4, preparation of sodium titanate: the sodium source and metatitanic acid are mixed uniformly according to a sodium and titanium molar ratio of 2:3, calcination is carried out under an argon atmosphere, and then natural cooling is carried out to obtain sodium titanate.
[0011] Further, the stirring speed in step S2 is 1000-1400 rpm.
[0012] Further, the concentration of the titanyl sulfate solution in step S2 is 170-240 g / L.
[0013] Further, the feeding speed of the titanyl sulfate solution in step S2 is 1.0-1.8 mL / min.
[0014] Further, the system temperature is constant at 80-110°C during the feeding process in step S2.
[0015] Further, the feeding time of the titanyl sulfate solution in step S2 is 2-12 h.
[0016] Further, the drying temperature in step S3 is 120°C, and the drying time is 10 h.
[0017] Further, the sodium source in step S4 is one or more of sodium acetate, sodium carbonate, sodium hydroxide, sodium oxalate, sodium oxide and sodium peroxide.
[0018] Further, the calcination in step S4 is: heating at a heating rate of 5°C / min to 800-950°C, and holding for 5-15 h.
[0019] The present application prepares metatitanic acid by hydrolysis of a titanyl sulfate solution, and then prepares sodium titanate from the metatitanic acid and a sodium source. The prepared sodium titanate has low cost, simple and easy process, a specific capacity of more than 82 mAh / g at 2000 mA / g, a capacity retention rate of more than 78.4% after 1000 cycles, and excellent product performance. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 SEM spectrum of the hydrolysis product metatitanic acid in Example 1 of the present application;
[0021] Figure 2 XRD spectrum of the hydrolysis product metatitanic acid in Example 1 of the present application;
[0022] Figure 3 SEM spectrum of the sodium titanate prepared in Example 1 of the present application;
[0023] Figure 4 XRD spectrum of the sodium titanate prepared in Example 1 of the present application;
[0024] Figure 5The performance graph of the sodium titanate negative electrode prepared in Embodiment 1 of the present application is cycled at 2000 mA / g for 1000 cycles;
[0025] Figure 6 The performance graph of the sodium titanate negative electrode prepared in Embodiment 1 of the present application is cycled at 2000 mA / g for 1000 cycles;
[0026] Figure 7 The rate performance graph of the sodium titanate negative electrode prepared in Embodiment 1 of the present application. DETAILED DESCRIPTION
[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application belong to the scope of protection of the present application.
[0028] Embodiment 1
[0029] A method for preparing a low-cost sodium titanate negative electrode material from a titanyl sulfate solution, the preparation method comprising the following steps:
[0030] S1, preheating of the base solution: take an appropriate amount of deionized water in a reaction kettle and preheat to 80°C;
[0031] S2, hydrolysis: under the condition of 1000 rpm stirring, a titanyl sulfate solution with a concentration of 170 g / L is added to the reaction kettle at a feeding speed of 1.8 mL / min, and the system temperature in the reaction kettle is kept constant at 80°C. The feeding time is 2 h, and the hydrolysis reaction ends when the feeding is completed.
[0032] S3, preparation of metatitanic acid: after hydrolysis, the slurry is cooled to room temperature, washed with water, and then dried at 120°C for 10 h to obtain metatitanic acid;
[0033] S4, preparation of sodium titanate: sodium oxalate and metatitanic acid are uniformly mixed according to a sodium to titanium molar ratio of 2:3, calcined under an argon atmosphere, heated to 800°C at a heating rate of 5°C / min, kept for 15 h, and then naturally cooled to obtain sodium titanate. The synthesized sodium titanate has a particle size of 6-10 microns and perfect sphericity, and achieves a specific capacity of 82 mAh / g at 2000 mA / g, and a capacity retention rate of 78.4% after 1000 cycles.
[0034] Embodiment 2
[0035] A method for preparing a low-cost sodium titanate negative electrode material from a titanyl sulfate solution, the preparation method comprising the following steps:
[0036] S1, preheating of the base solution: take an appropriate amount of deionized water in a reaction kettle and preheat to 90°C;
[0037] S2, hydrolysis: under the condition of stirring at 1100 rpm, the titanyl sulfate solution with a concentration of 190 g / L was added into the reactor at a feeding rate of 1.5 mL / min, and the temperature of the system in the reactor was kept constant at 90°C, the feeding time was 5 h, and the hydrolysis reaction ended when the feeding was completed;
[0038] S3, preparation of metatitanic acid: the slurry after hydrolysis was cooled to room temperature, and then dried at 120°C for 10 h after water washing to obtain metatitanic acid;
[0039] S4, preparation of sodium titanate: sodium hydroxide and metatitanic acid were uniformly mixed according to a sodium-titanium molar ratio of 2:3, calcination was performed under an argon atmosphere, the temperature was raised to 850°C at a heating rate of 5°C / min, the temperature was kept constant for 7 h, and then natural cooling was performed to obtain sodium titanate. The particle size of the synthesized sodium titanate was 4-10 microns, the sphericity was good, the specific capacity of the sodium titanate reached 113 mAh / g at 2000 mA / g, and the capacity retention rate was 81% after 1000 cycles.
[0040] Example 3
[0041] A method for preparing a low-cost sodium titanate negative material from a titanyl sulfate solution, the preparation method comprising the following steps:
[0042] S1, preheating of the base solution: an appropriate amount of deionized water was taken in a reactor and preheated to 100°C;
[0043] S2, hydrolysis: under the condition of stirring at 1200 rpm, the titanyl sulfate solution with a concentration of 210 g / L was added into the reactor at a feeding rate of 1.2 mL / min, and the temperature of the system in the reactor was kept constant at 100°C, the feeding time was 8 h, and the hydrolysis reaction ended when the feeding was completed;
[0044] S3, preparation of metatitanic acid: the slurry after hydrolysis was cooled to room temperature, and then dried at 120°C for 10 h after water washing to obtain metatitanic acid;
[0045] S4, preparation of sodium titanate: sodium acetate and metatitanic acid were uniformly mixed according to a sodium-titanium molar ratio of 2:3, calcination was performed under an argon atmosphere, the temperature was raised to 900°C at a heating rate of 5°C / min, the temperature was kept constant for 10 h, and then natural cooling was performed to obtain sodium titanate. The particle size of the synthesized sodium titanate was 1-6 microns, the sphericity was good, the specific capacity reached 103 mAh / g at 2000 mA / g, and the capacity retention rate was 86% after 1000 cycles.
[0046] Example 4
[0047] A method for preparing a low-cost sodium titanate negative material from a titanyl sulfate solution, the preparation method comprising the following steps:
[0048] S1, bottom liquid preheating: take an appropriate amount of deionized water in the reaction kettle, and preheat to 110°C;
[0049] S2, hydrolysis: under the condition of 1400 rpm stirring, the concentration of 240 g / L titanyl sulfate solution was added to the reaction kettle at a feeding speed of 1.0 mL / min, and the system temperature in the reaction kettle was kept constant at 110°C, the feeding time was 12 h, and the hydrolysis reaction ended when the feeding ended;
[0050] S3, preparation of metatitanic acid: after hydrolysis, the slurry was cooled to room temperature, washed with water, and dried at 120°C for 10 h to obtain metatitanic acid;
[0051] S4, preparation of sodium titanate: sodium carbonate and metatitanic acid were mixed uniformly according to a sodium to titanium molar ratio of 2:3, calcined under an argon atmosphere, heated to 950°C at a heating rate of 5°C / min, kept for 5 h, and then naturally cooled to obtain sodium titanate. The particle size of the synthesized sodium titanate is 6-10 microns, the sphericity is good, the specific capacity of the sodium titanate reaches 96 mAh / g at 2000 mA / g, and the capacity retention rate is 79.2% after 1000 cycles.
[0052] Example 5
[0053] A method for preparing low-cost sodium titanate negative material from titanyl sulfate solution, the preparation method comprising the following steps:
[0054] S1, bottom liquid preheating: take an appropriate amount of deionized water in the reaction kettle, and preheat to 85°C;
[0055] S2, hydrolysis: under the condition of 1300 rpm stirring, the concentration of 180 g / L titanyl sulfate solution was added to the reaction kettle at a feeding speed of 1.6 mL / min, and the system temperature in the reaction kettle was kept constant at 85°C, the feeding time was 10 h, and the hydrolysis reaction ended when the feeding ended;
[0056] S3, preparation of metatitanic acid: after hydrolysis, the slurry was cooled to room temperature, washed with water, and dried at 120°C for 10 h to obtain metatitanic acid;
[0057] S4, preparation of sodium titanate: sodium carbonate and metatitanic acid were mixed uniformly according to a sodium to titanium molar ratio of 2:3, calcined under an argon atmosphere, heated to 850°C at a heating rate of 5°C / min, kept for 12 h, and then naturally cooled to obtain sodium titanate. The particle size of the synthesized sodium titanate is 1-6 microns, the sphericity is good, the specific capacity reaches 106 mAh / g at 2000 mA / g, and the capacity retention rate is 83% after 1000 cycles.
[0058] Example 6
[0059] A method for preparing a low-cost sodium titanate negative material from a titanyl sulfate solution, the preparation method comprising the following steps:
[0060] S1, preheating of the base solution: take an appropriate amount of deionized water in a reaction kettle and preheat to 95°C;
[0061] S2, hydrolysis: under the condition of stirring at 1150 rpm, add a titanyl sulfate solution with a concentration of 220 g / L to the reaction kettle at a feeding speed of 1.3 mL / min, keep the temperature of the system in the reaction kettle constant at 95°C, the feeding time is 7h, and the hydrolysis reaction ends when the feeding is completed;
[0062] S3, preparation of metatitanic acid: cool the hydrolyzed slurry to room temperature, wash with water, and then dry at 120°C for 10h to obtain metatitanic acid;
[0063] S4, preparation of sodium titanate: mix sodium peroxide and metatitanic acid uniformly according to a sodium to titanium molar ratio of 2:3, perform calcination under an argon atmosphere, heat to 900°C at a heating rate of 5°C / min, keep the temperature for 8h, and then naturally cool to obtain sodium titanate. The synthesized sodium titanate has a particle size of 1-5 microns, perfect sphericity, a specific capacity of 108 mAh / g at 2000 mA / g, and a capacity retention rate of 85% after 1000 cycles.
[0064] Comparative Example 1
[0065] A method for preparing a traditional sodium titanate negative material, the preparation method using anatase titanium dioxide (titanium white) as a titanium source, calcining with a sodium source, and then naturally cooling to obtain a sodium titanate negative material.
[0066] The preparation method of anatase titanium dioxide generally uses the sulfuric acid method, comprising the following steps:
[0067] S1, preparation of raw ore: crush and magnetically separate the titanium ore;
[0068] S2, preparation of titanium sulfate: use sulfuric acid to decompose the titanium ore into TiOSO4;
[0069] S3, preparation of hydrated titanium dioxide: hydrolyze TiOSO4 into TiO2·H2O;
[0070] S4, calcination: calcine the hydrolysis product into titanium dioxide;
[0071] S5, post-treatment: including surface treatment, separation and impurity removal to obtain a titanium white product.
[0072] After the titanyl sulfate solution is hydrolyzed into metatitanic acid, it undergoes calcination, surface treatment, impurity removal and other energy-consuming links, and this process also produces wastewater, waste gas and solid waste, which need to be treated to meet environmental protection standards, which also constitutes part of the cost.
[0073] In addition, the key link affecting the size and morphology performance of the final product is the hydrolysis of the titanyl sulfate solution, i.e. the reaction of titanyl sulfate with water to generate hydrated titanium dioxide (metatitanic acid) precipitate and sulfuric acid:
[0074] TiOSO4+ 2H2O→TiO2·H2O + H2SO4
[0075] At present, multiple parameters need to be accurately controlled in the hydrolysis process of titanyl sulfate, such as the acidity (pH value) of the solution, and the particle size and morphology of metatitanic acid can also be controlled by adding seeds or adjusting the hydrolysis conditions, which undoubtedly increases the production cost.
[0076] In the preparation method of the present application, metatitanic acid is directly used as a titanium source to calcine with a sodium source to prepare sodium titanate, compared with the above-mentioned traditional method, multiple energy consumption links such as calcination, surface treatment and impurity removal from metatitanic acid to titanium dioxide are omitted, and the hydrolysis of titanyl sulfate does not need to add seeds and adjust the pH of the system, which reduces the complexity of the operation, improves the production efficiency, and the obtained hydrolysis product metatitanic acid has good sphericity and uniform particles.
[0077] Comparative Example 2
[0078] Metatitanic acid precursor was prepared by hydrolysis using industrial titanium liquid as a titanium source.
[0079] The industrial titanium liquid and the bottom water were preheated to 96℃ respectively before the reaction, then the titanium liquid was uniformly added into a three-necked flask containing the bottom water within 16 min by using a peristaltic pump, after the addition was completed, the temperature was raised to the micro-boiling state of the solution in the flask (the first boiling point was 106℃), and the color change of the titanium liquid was observed. When the titanium liquid turned to steel gray, the heating and stirring were immediately turned off, and the aging was performed for 30 min. After the aging was completed, the heating and stirring were restarted, and when the titanium liquid reached the micro-boiling state again (the second boiling point was 108℃), the reaction timing was started. After 3 h of reaction, 10 mL of hot water was added, and the reaction was continued for 1 h. Then the heating and stirring were turned off, and the reaction slurry was cooled to about 45℃. Then the slurry was vacuum filtered and dried. 2 g of metatitanic acid precursor was weighed according to n(Na)∶n(Ti) of 2∶3, with 5% (mass fraction) excess of sodium source. 10 mL of anhydrous ethanol was taken as a dispersant, added to a nylon ball mill tank, and ball milled in a high-speed ball mill for 2 h. The slurry was taken out and placed on a watch glass. After removing a large amount of anhydrous ethanol by air drying at room temperature, it was placed in a 60℃ oven for drying for 90 min. The dried material was scraped off, placed in a mortar, and ground thoroughly. Then the mixture was moved into a square porcelain boat, and the porcelain boat was placed in a muffle furnace for calcination in an air atmosphere. The calcination temperature was 800℃, the constant temperature was 20 h, and the heating / cooling rate was 5℃ / min.
[0080] The sodium titanate synthesized in Comparative Example 2 mainly contains Na2Ti3O7 and Na2Ti6O 13the initial discharge specific capacity can reach 233.77 mA·h / g at a low current density of 17.7 mA / g; after 200 cycles at a current density of 88.5 mA / g, the discharge specific capacity is 26.87 mA·h / g, the capacity retention rate is 47.56%, and the charge-discharge efficiency is 99.54%; and the sodium storage process of the prepared mixed sodium titanate is dominated by pseudo-capacitive behavior.
[0081] The method for synthesizing sodium titanate in Comparative Example 2 shortens the process for preparing sodium titanate, but the hydrolysis process is too complex, and the electrochemical performance of the synthesized material is poor.
[0082] Experimental results and analysis
[0083] Figure 1 SEM spectrum of the metatitanic acid hydrolysis product in Example 1 of the application; Figure 2 XRD spectrum of the metatitanic acid hydrolysis product in Example 1 of the application; it can be seen that the metatitanic acid hydrolysis product in Example 1 has good sphericity, the particles are uniform, and the particle size is about 1-5 microns. The metatitanic acid corresponds to the anatase titanium dioxide phase.
[0084] Figure 3 SEM spectrum of the sodium titanate prepared in Example 1 of the application; Figure 4 XRD spectrum of the sodium titanate prepared in Example 1 of the application; it can be seen that the sodium titanate prepared in Example 1 is a spherical nanoflower with nanorod and nanosheet accumulation, and the sodium titanate is mainly a mixed phase of Na2Ti3O7 and Na2Ti6O 13 , and in addition, there is a Na2SO4 phase.
[0085] Figure 5 Performance graph of the sodium titanate negative electrode prepared in Example 1 of the application at 200 mA / g after 200 cycles; it can be seen that the capacity retention rate of the sodium titanate negative electrode prepared in Example 1 is 86% after 200 cycles at 200 mA / g.
[0086] Figure 6 Performance graph of the sodium titanate negative electrode prepared in Example 1 of the application at 2000 mA / g after 1000 cycles; it can be seen that the sodium titanate negative electrode prepared in Example 1 realizes a capacity retention rate of 78.4% at 2000 mA / g after 1000 cycles.
[0087] Figure 7 Rate performance graph of the sodium titanate negative electrode prepared in Example 1 of the application; it can be seen that the sodium titanate negative electrode prepared in Example 1 realizes a specific capacity of 82 mAh / g at 2000 mA / g.
[0088] In summary, the beneficial effects brought by the technical scheme of the application are as follows:
[0089] 1. The application directly hydrolyzes titanyl sulfate solution at constant temperature and constant rotating speed to obtain metatitanic acid without needing crystal seeds and adjusting the pH of the system, reduces operation complexity, improves production efficiency, and obtains metatitanic acid hydrolysis products with good sphericity and uniform particles.
[0090] 2. The application directly calcines metatitanic acid as a source of titanic acid and sodium to prepare sodium titanate, omits multiple energy consumption links such as calcination, surface treatment and impurity removal from metatitanic acid to titanium dioxide, greatly reduces the production cost of sodium titanate, and has great economic effect.
[0091] 3. The prepared sodium titanate negative material has excellent performance, realizes that the specific capacity of sodium titanate reaches more than 82 mAh / g at 2000 mA / g, and the capacity retention rate reaches more than 78.4% after 1000 cycles.
[0092] The above only describes preferred embodiments of the application and is not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the application shall be included in the protection scope of the application.
Claims
1. A method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution, the method comprising the following steps: S1. Preheating of the base solution: Take an appropriate amount of deionized water into the reactor and preheat it to 80℃-110℃; S2. Hydrolysis: Under stirring, the titanium oxysulfate solution is added to the reactor at a constant rate, and the temperature of the system inside the reactor is kept constant. The hydrolysis reaction ends when the feeding is finished. S3. Preparation of metatitanic acid: Cool the hydrolyzed slurry to room temperature, wash it with water, and dry it to obtain metatitanic acid. S4. Preparation of sodium titanate: Sodium source and metatitanic acid are mixed evenly at a sodium to titanium molar ratio of 2:3, calcined under an argon atmosphere, and then naturally cooled to obtain sodium titanate. In step S2, the concentration of the titanium oxysulfate solution is 170-220 g / L; In step S4, the calcination is performed by heating the temperature to 800-950℃ at a rate of 5℃ / min and holding it at that temperature for 5-15 hours.
2. The method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution according to claim 1, characterized in that, The stirring speed in step S2 is 1000-1400 rpm.
3. The method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution according to claim 1, characterized in that, In step S2, the feed rate of the titanium oxysulfate solution is 1.0-1.8 mL / min.
4. The method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution according to claim 1, characterized in that, The feeding time for the titanium oxysulfate solution in step S2 is 2-12 hours.
5. The method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution according to claim 1, characterized in that, In step S3, the drying temperature is 120℃ and the drying time is 10 hours.
6. The method for preparing low-cost sodium titanate anode material from a titanium oxysulfate solution according to any one of claims 1 to 5, characterized in that, In step S4, the sodium source is one or more of sodium acetate, sodium carbonate, sodium hydroxide, sodium oxalate, sodium oxide, and sodium peroxide.