Method for preparing lithium molybdate powder with adjustable particle size by reaction ball milling

Abstract

The method for preparing adjustable-size lithium molybdate powder by reactive ball milling uses Li2MoO4 as the chemical formula, with a purity ≥99.5% and a particle size satisfying 0.1μm≤D50≤50μm. The powder is white and comprises six steps and conditions: batching, ball milling, sieving and drying, annealing, and pulverizing. This method offers advantages such as precise control of powder particle size, significantly reduced preparation time, simplified preparation process, and improved product yield.

Description

Technical Field

[0001] This invention relates to the field of new energy material powder preparation technology, and in particular to a method for preparing lithium molybdate powder with adjustable particle size by reactive ball milling. Background Technology

[0002] Lithium molybdate (Li₂MoO₄), as a novel inorganic functional material, has shown diverse application prospects in the field of lithium-ion batteries due to its rich valence state variations (Mo can exhibit +4 and +6 valences), unique stable framework structure, and excellent mechanical properties. Currently, it has been widely used in the modification of ternary cathode materials and silicon-carbon anode materials, as well as in the construction of solid sulfide electrolytes.

[0003] Benefiting from its high Young's modulus and thermodynamically stable hexagonal phase crystal structure, lithium molybdate exhibits excellent mechanical support strength and structural stability in battery systems. Studies have shown that its introduction into battery material systems can effectively suppress the structural collapse of ternary cathode materials during lithium insertion / extraction, alleviate the severe volume expansion effect and interfacial side reactions faced by silicon anode materials, and improve the core technical bottlenecks such as the low ionic conductivity of solid electrolyte materials, thereby significantly improving the overall cycle life and safety performance of batteries. However, traditional preparation processes still have many technical problems that need to be solved: (1) Lithium molybdate prepared by traditional solid-phase methods has poor morphology, high energy consumption, and sintering temperature is usually greater than 450℃; (2) Although traditional liquid-phase methods can reduce reaction energy consumption, they generally have problems such as long reaction cycles, product purity being affected by impurity ions, and limited yield, which are difficult to meet the needs of large-scale industrial production.

[0004] To address the aforementioned issues, several researchers have published methods, including CN105293579A, "A method for preparing lithium molybdate." This method, a liquid-phase process, prepares lithium molybdate powder using ammonium molybdate as a raw material. Molybdate acid is prepared by adding seed crystals and controlling the feeding method and pH of the reaction system. Finally, battery-grade lithium hydroxide is added to produce the final lithium molybdate product. The entire process includes steps such as batching, acid precipitation, molybdate acid purification, alkali dissolution, ammonium removal, evaporation and concentration, cooling and crystallization, and drying. While this method can reduce reaction energy consumption, it suffers from problems such as a long reaction cycle, product purity being affected by impurity ions, and limited yield, making it difficult to meet industrial-scale requirements. The need for large-scale production: CN112441617A "A method for preparing lithium molybdate powder" involves directly mixing lithium carbonate powder and molybdenum oxide powder with deionized water, heating to 40-90℃ to allow the chemical reaction to proceed rapidly in solution and form a lithium molybdate solution, followed by filtration and drying to obtain lithium molybdate powder. This method can reduce reaction temperature, reduce energy consumption, improve preparation efficiency, and obtain lithium molybdate powder products with high purity. However, from an industrialization perspective, it still has technical pain points such as complex process flow, long experimental cycle, and difficulty in scaling up the subsequent filtration and drying process, which are not conducive to its industrial application.

[0005] Therefore, it is of great significance to develop a method for preparing lithium molybdate powder of different particle sizes using reactive ball milling with low energy consumption. Summary of the Invention

[0006] The objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing adjustable particle size lithium molybdate powder by reactive ball milling. This method can precisely control the powder particle size, and can also greatly shorten the preparation time, simplify the preparation process, and improve the product yield.

[0007] The objective of this invention is achieved through the following technical solution: Adjustable particle size lithium molybdate powder was prepared by reactive ball milling. The chemical formula of the lithium molybdate powder is Li2MoO4, the purity is ≥99.5%, the particle size meets the requirement of 0.1μm≤D50≤50μm, and it is a white powder II.

[0008] A method for preparing adjustable particle size lithium molybdate powder by reactive ball milling includes the following steps and conditions: ingredient preparation, ball milling, sieving and drying, annealing, and pulverization. S1: Weigh the lithium source and molybdenum source according to the stoichiometric ratio of lithium molybdate (Li2MoO4), and measure an appropriate amount of dispersant, and mix them thoroughly to obtain mixture A; S2: Add mixture A to the ball mill jar and set the ball milling parameters to perform reaction ball milling; S3: The white mixture B obtained after ball milling and zirconium beads are ultrasonically sieved to separate the zirconium beads and the white mixture. The sieved white mixture B is placed in an oven for low-temperature drying to obtain powder I. S4: Place powder I in a tube furnace or atmosphere box furnace for low-temperature annealing to obtain white powder II; S5: Crush and sieve the white powder II to obtain qualified lithium molybdate product.

[0009] The innovation of this invention compared with the prior art lies in: (1) Lithium molybdate samples can be obtained by ball milling molybdenum source, lithium source and dispersant according to stoichiometric ratio, followed by low-temperature annealing. The entire process is simple, easy to operate, has low equipment dependence, low energy consumption and low processing cost, and meets the requirements of green chemistry processes. The preparation process is suitable for industrial production. (2) By adjusting the ball mill speed, interval time, milling time, and dispersant quality, the reaction rate and local thermal effect are precisely controlled, thereby achieving the regulation of the morphology, size, and particle size distribution of lithium molybdate powder. The median particle size of the obtained lithium molybdate powder can be arbitrarily adjusted within the range of 0.1 μm to 50 μm, and the product morphology and particle size are easily controlled.

[0010] The advantages or effects of this invention are as follows: (1) Because the prepared lithium molybdate has high crystallinity, controllable particle size and regular morphology and the preparation process is simple, the preparation cycle is short, the energy consumption is low, the product quality is stable and controllable, and it is easy to scale up to industrial scale.

[0011] (2) At the same time, since the lithium molybdate sample can be obtained by ball milling the molybdenum source, lithium source and dispersant according to the stoichiometric ratio and then annealing at low temperature, the process is simple, easy to operate, and has low dependence on equipment, low energy consumption and low processing cost.

[0012] (3) In addition, by adjusting the ball milling speed, interval time, ball milling time and the mass of dispersant, the reaction rate and local thermal effect can be precisely controlled, thereby achieving the regulation of the morphology, size and particle size distribution of lithium molybdate powder. The median particle size of the obtained lithium molybdate powder can be arbitrarily adjusted in the range of 0.1μm to 50μm. The morphology and particle size of the product are easy to control, and the preparation process is suitable for industrial production applications.

[0013] (4) In addition, since the purity of the obtained high-purity lithium molybdate powder is ≥99.5% and its wide particle size distribution is 0.1μm≤D50≤50μm, it can meet the requirements of chemical analysis grade and battery grade materials. It can ensure that the material can be used for doping and coating of solid electrolytes and electrodes, as well as for refrigerator corrosion inhibitors, metal ceramics and resistors. Attached Figure Description

[0014] Figure 1This invention provides a process flow diagram for preparing adjustable particle size lithium molybdate powder using reactive ball milling.

[0015] The present invention will now be described in further detail with reference to the accompanying drawings. Detailed Implementation

[0016] The chemical formula of the adjustable particle size lithium molybdate powder prepared by reactive ball milling is Li2MoO4, with a purity ≥99.5% and a particle size satisfying 0.1μm≤D50≤50μm. It is a white powder.

[0017] The adjustable particle size lithium molybdate powder of the present invention further comprises: Nanoscale lithium molybdate powder (0.1μm≤D50≤3μm) is suitable for doping and coating battery materials. Due to its stable framework structure, high ionic conductivity and diverse valence states, it is suitable for improving the cycle stability and ionic conductivity of oxide solid electrolyte LLZTO, ternary high-nickel cathode materials and silicon-carbon anodes.

[0018] Micron-sized lithium molybdate powder (3μm≤D50≤50μm) is suitable for chemical corrosion inhibitors, cermets and resistor materials.

[0019] A method for preparing adjustable particle size lithium molybdate powder by reactive ball milling includes the following steps and conditions: ingredient preparation, ball milling, sieving and drying, annealing, and pulverization. S1: Weigh the lithium source and molybdenum source according to the stoichiometric ratio of lithium molybdate (Li2MoO4), and measure an appropriate amount of dispersant, and mix them thoroughly to obtain mixture A; S2: Add mixture A to the ball mill jar and set the ball milling parameters to perform reaction ball milling; S3: The white mixture B obtained after ball milling and zirconium beads are ultrasonically sieved to separate the zirconium beads and the white mixture. The sieved white mixture B is placed in an oven for low-temperature drying to obtain powder I. S4: Place powder I in a tube furnace or atmosphere box furnace for low-temperature annealing to obtain white powder II; S5: Crush and sieve the white powder II to obtain qualified lithium molybdate product.

[0020] A further method for preparing adjustable particle size lithium molybdate powder using reactive ball milling is: In step S1, the molybdenum source is any one or more of molybdenum trioxide, molybdic acid, and ammonium molybdate.

[0021] In step S1, the lithium source is one or more of lithium carbonate, lithium hydroxide, lithium oxalate, etc.

[0022] The dispersant in step S1 is one or more of pure water, ethanol, propanol, isopropanol, etc.

[0023] In step S1, the mass ratio of lithium source to molybdenum source is 1.5~4.0:1.0~2.0, and the mass ratio of dispersant is 0.5~20%. The lithium source, molybdenum source and dispersant are mixed uniformly.

[0024] In step S2, the ball milling equipment is a high-energy planetary ball mill with a ball milling speed of 200~600 rpm, a ball milling time of 30 min~24 h, and a ball milling jar filling amount of 30~60%.

[0025] In step S3, low-temperature drying involves removing the dispersant and small amounts of impurities (NH3, CO2) generated during the reaction in a vacuum oven or forced-air oven at a temperature of 60~120℃ for 2~36 hours.

[0026] In step S4, the annealing temperature is 200~400℃, the annealing time is 2~15h, and the annealing atmosphere is any one or more of air, oxygen, nitrogen, and argon. Example 1

[0027] This embodiment provides a lithium molybdate material and its preparation method, including the following steps: S1. Weigh 14.4g of nano-molybdenum oxide and 7.4g of lithium carbonate according to the stoichiometric ratio of lithium molybdate (Li2MoO4), add 5% pure water, and mix thoroughly to obtain mixture A; S2. Add mixture A into the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. First run at 300 rpm for 1 hour, then run at 480 rpm for 1 hour. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 80℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 200°C for 6 hours in an oxygen atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size. Example 2

[0028] This embodiment provides a lithium molybdate material and its preparation method. The specific experimental steps are as follows: S1. Weigh 14.4g of molybdic acid and 6.4g of lithium hydroxide according to the stoichiometric ratio of lithium molybdate (Li2MoO4), and add them to a 5% ethanol and water mixture (ethanol:water = 3:2). Mix thoroughly to obtain mixture A. S2. Add mixture A into the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. First run at 300 rpm for 1 hour, then run at 380 rpm for 4 hours. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 80℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 180°C for 5 hours in air atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size. Example 3

[0029] This embodiment provides a lithium molybdate material and its preparation method. The specific experimental steps are as follows: S1. Weigh 13.5g of molybdic acid and 7.7g of lithium hydroxide monohydrate according to the stoichiometric ratio of lithium molybdate (Li2MoO4), add 15% pure water, and mix thoroughly to obtain mixture A; S2. Add mixture A into the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. First run at 300 rpm for 1 hour, then run at 400 rpm for 6 hours. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 90℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 300°C for 8 hours in an oxygen atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size. Example 4

[0030] This embodiment provides a lithium molybdate material and its preparation method. The specific experimental steps are as follows: S1. Weigh 12.3g of molybdic acid and 6.8g of lithium carbonate according to the stoichiometric ratio of lithium molybdate (Li2MoO4), and add 5% propanol, and mix thoroughly to obtain mixture A; S2. Add mixture A into the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. First run at 300 rpm for 1 hour, then run at 480 rpm for 2 hours. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 80℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 250°C for 6 hours in an oxygen atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size. Example 5

[0031] This embodiment provides a lithium molybdate material and its preparation method. The specific experimental steps are as follows: S1. Weigh 12.5g of molybdic acid and 7.9g of lithium hydroxide monohydrate according to the stoichiometric ratio of lithium molybdate (Li2MoO4), add 4% pure water, and mix thoroughly to obtain mixture A; S2. Add mixture A into the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. First run at 300 rpm for 1 hour, then run at 400 rpm for 3 hours. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 80℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 400°C for 4 hours in an oxygen atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size. Example 6

[0032] This embodiment provides a lithium molybdate material and its preparation method. The specific experimental steps are as follows: S1. Weigh 14.4g of nano-molybdenum oxide and 7.4g of lithium carbonate according to the stoichiometric ratio of lithium molybdate (Li2MoO4), add 8% pure water, and mix thoroughly to obtain mixture A; S2. Add mixture A to the ball mill jar, set the ball milling parameters and perform reaction ball milling. The mass ratio of grinding balls to grinding material is 15:1, and the mass ratio of large, medium and small grinding balls is 2:5:3. Run at 300 rpm for 3 hours. S3. The mixture B obtained after ball milling is sonicated together with zirconium beads for 30 min, and then sieved through a 100-mesh sieve to separate the zirconium beads and mixture B. Mixture B is placed in an oven and dried at a low temperature of 90℃ to obtain powder I. S4. Place powder I in a tube furnace and anneal it at 200°C for 10 hours in an oxygen atmosphere to obtain white powder II; S5. Use a high-speed blender to pulverize white powder II in small batches multiple times, and finally sieve it through a 300-mesh sieve to obtain lithium molybdate product with qualified particle size.

[0033] The lithium molybdate powder materials obtained in the above embodiments were characterized by particle size analysis using a Malvern laser particle size analyzer. The test results are shown in Table 1 below. Table 1. Summary of Test Results for Each Case

[0034]

[0035] Notes: Example 1 uses nano-sized molybdenum oxide and water as a solvent to prepare sub-meter-sized lithium molybdate at a high milling speed of 480 rpm, suitable for doping and coating of battery materials; Example 2 uses molybdic acid and lithium hydroxide as raw materials and a mixture of water and ethanol as a solvent. The organic solvent ethanol can effectively inhibit particle growth, and the D50 of lithium molybdate is 3.42 μm; Example 3 uses the same raw materials as Example 2, but uses water as a solvent and the ball milling speed is 400 rpm, so micron-sized lithium molybdate is obtained; Example 4 uses molybdic acid, lithium carbonate, and propanol as raw materials and successfully prepares nano-sized lithium molybdate at a high milling speed of 480 rpm, suitable for doping and coating of solid electrolyte materials and cathode materials; Example 5 is similar to Example 3, except that the amount of solvent water is reduced, so the particle size of lithium molybdate is similar, all in the micron range; Example 6 uses the same raw materials as Example 1, but the ball milling speed is low, only 300 rpm, so the lithium molybdate particles are larger, with a D50 of 34.4 μm.

[0036] As described above, the present invention can be well implemented. The above embodiments are only the best implementations of the present invention, but the implementation of the present invention is not limited to the above embodiments. Other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are all included within the protection scope of the present invention.

Claims

1. A method for preparing adjustable particle size lithium molybdate powder by reactive ball milling, characterized in that... The chemical formula of lithium molybdate powder is Li2MoO4, with a purity ≥99.5% and a particle size satisfying 0.1μm≤D50≤50μm. It is a white powder.

2. The powder according to claim 1, characterized in that... Nanoscale lithium molybdate powder (0.1μm≤D50≤3μm) is suitable for doping and coating battery materials. Due to its stable framework structure, high ionic conductivity and diverse valence states, it is suitable for improving the cycle stability and ionic conductivity of oxide solid electrolyte LLZTO, ternary high-nickel cathode materials and silicon-carbon anodes.

3. The powder according to claim 1, characterized in that... Micron-sized lithium molybdate powder (3μm≤D50≤50μm) is suitable for chemical corrosion inhibitors, cermets and resistor materials.

4. A method for preparing adjustable particle size lithium molybdate powder using reactive ball milling, characterized in that... Ingredient preparation, ball milling, sieving and drying, annealing and pulverizing, specifically including the following steps and conditions: S1: Weigh the lithium source and molybdenum source according to the stoichiometric ratio of lithium molybdate (Li2MoO4), and measure an appropriate amount of dispersant, and mix them thoroughly to obtain mixture A; S2: Add mixture A to the ball mill jar and set the ball milling parameters to perform reaction ball milling; S3: The white mixture B obtained after ball milling and zirconium beads are ultrasonically sieved to separate the zirconium beads and the white mixture. The sieved white mixture B is placed in an oven for low-temperature drying to obtain powder I. S4: Place powder I in a tube furnace or atmosphere box furnace for low-temperature annealing to obtain white powder II; S5: Crush and sieve the white powder II to obtain qualified lithium molybdate product.

5. The method according to claim 4, characterized in that: In step S1, the molybdenum source is any one or more of molybdenum trioxide, molybdic acid, and ammonium molybdate.

6. The method according to claim 4, characterized in that: In step S1, the lithium source is one or more of lithium carbonate, lithium hydroxide, lithium oxalate, etc.

7. The method according to claim 4, characterized in that: The dispersant in step S1 is one or more of pure water, ethanol, propanol, isopropanol, etc.

8. The method according to claim 4, 5, 6, or 7, characterized in that: In step S1, the mass ratio of lithium source to molybdenum source is 1.5~4.0:1.0~2.0, and the mass ratio of dispersant is 0.5~20%. The lithium source, molybdenum source and dispersant are mixed uniformly.

9. The method according to claim 4, characterized in that: In step S2, the ball milling equipment is a high-energy planetary ball mill with a ball milling speed of 200~600 rpm, a ball milling time of 30 min~24 h, and a ball milling jar filling amount of 30~60%.

10. The method according to claim 4, characterized in that... In step S3, low-temperature drying is performed in a vacuum oven or forced-air oven to remove the dispersant and small amounts of impurities (NH3, CO2) generated during the reaction. The temperature is 60~120℃ and the drying time is 2~36h.

11. The method according to claim 4, characterized in that: In step S4, the annealing temperature is 200~400℃, the annealing time is 2~15h, and the annealing atmosphere is any one or more of air, oxygen, nitrogen, and argon.

Images