A modification method for constructing MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material
By coating the surface of lithium manganese iron phosphate with MoS2/NiO/TiO2 nanoparticles, the problems of low conductivity and low lithium-ion diffusion rate of lithium manganese iron phosphate are solved, thereby improving the material performance and making it suitable for lithium-ion battery cathode materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUBEI XINGFA CHEM GRP CO LTD
- Filing Date
- 2024-06-11
- Publication Date
- 2026-07-10
AI Technical Summary
The poor conductivity and low lithium-ion diffusion rate of lithium manganese iron phosphate materials prevent them from fully realizing their electrochemical performance, thus limiting their application in lithium-ion batteries.
MoS2/NiO/TiO2 nanoparticles were synthesized via hydrothermal reaction and coated onto the surface of lithium manganese iron phosphate to improve the material's conductivity and ion diffusion rate.
It significantly improves the conductivity and lithium-ion diffusion rate of lithium manganese iron phosphate materials, enhances the specific capacity and energy density of batteries, and improves electrochemical performance.
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Figure CN118771334B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for constructing MoS2 / NiO / TiO2 to improve the electrochemical performance of lithium manganese iron phosphate. The modified lithium manganese iron phosphate can be used as a cathode material for lithium-ion batteries and can be used to manufacture various types of power batteries. Background Technology
[0002] With the increasing severity of environmental pollution and energy shortages, the collection and conversion of renewable energy sources such as solar, wind, and geothermal energy have attracted growing attention from researchers in recent years. Lithium-ion batteries, used for energy storage, are widely applied in portable electronic products such as mobile phones, laptops, and cameras. Today, lithium-ion batteries have even broader application prospects in large-scale energy storage power stations and new energy vehicles. However, despite significant progress in over 20 years of development, the current energy and power density of lithium-ion batteries still cannot meet the requirements of electric vehicles for driving range and charging speed. The cathode material accounts for a considerable proportion of the battery's cost, weight, and volume, making it a core factor restricting the development of high-performance batteries. Lithium manganese iron phosphate, as a novel cathode material, possesses advantages such as high energy density, high voltage platform, and good safety performance, and is considered a promising cathode material for lithium-ion batteries.
[0003] However, due to its olivine-type structure, lithium manganese iron phosphate (LFP) has FeO6 and MnO6 located on octahedra, lacking a continuous FeO6 (MnO6) edge-sharing octahedral network. Instead, it is connected by PO4 tetrahedra, resulting in poor conductivity. Simultaneously, the PO4 tetrahedra located between the FeO6 (MnO6) octahedra block lithium-ion diffusion channels, restricting lithium ions to movement only in one-dimensional channels, leading to a low lithium-ion diffusion rate and poor rate performance. These drawbacks prevent LFP from fully realizing its electrochemical performance and limit its further large-scale commercial applications. Therefore, improving the conductivity of LFP and optimizing its electrical properties is of great significance. Summary of the Invention
[0004] To address the above issues, this invention provides a method for modifying lithium manganese iron phosphate by synthesizing molybdenum disulfide, nickel oxide, and titanium dioxide nanoparticles and coating them onto the surface of lithium manganese iron phosphate. This preparation process is simple and improves the conductivity of the material to meet the performance requirements of power batteries and electronic devices.
[0005] To solve the technical problems of the appeal, the present invention adopts the following technical solution:
[0006] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0007] S1: Mix nickel nitrate and sodium hydroxide thoroughly, add water, and sonicate until homogeneous to obtain a nickel-lithium mixture; mix ammonium molybdate and thiourea solution thoroughly, add water, and sonicate until homogeneous to obtain a molybdenum source mixture;
[0008] S2: The nickel-lithium mixture and the molybdenum source mixture obtained in S1 were subjected to hydrothermal reactions to obtain NiO and MoS2 solid particles, respectively.
[0009] S3: Tetrabutyl titanate, MoS2 solid particles and NiO solid particles are placed in an alcohol solution, stirred evenly, and then salt is added. After standing, the mixture is washed and vacuum dried to obtain MoS2 / NiO / TiO2 solid particles.
[0010] S4: Mix the obtained MoS2 / NiO / TiO2 solid particles with lithium iron manganese phosphate particles in a certain proportion, add water, stir and let stand, centrifuge and wash and then dry to obtain lithium iron manganese phosphate cathode material coated with MoS2 / NiO / TiO2 composite material.
[0011] The nickel salt is selected from any one of Ni(NO3)2, nickel chloride, nickel sulfate, and nickel acetate, and the mass ratio of the nickel salt to sodium hydroxide is 1:2-3. Alternatively, commercially available nickel nitrate can be used directly.
[0012] The mass ratio of nickel nitrate to sodium hydroxide in S1 is 1:2-3.
[0013] The mass ratio of ammonium molybdate to thiourea in S1 is 1:2~3.
[0014] The heating temperature of the hydrothermal reactor in S2 is 180-230℃, and the holding time is 10-24 h.
[0015] The mass ratio of S3 tetrabutyl titanate, MoS2 solid particles, and NiO solid particles is 1-2.5:2~3:2~3.
[0016] The salt in S3 is any one of potassium chloride, sodium chloride, calcium chloride, and magnesium chloride; the salt concentration is 0.1-0.3M. The salt is added to avoid the influence of pH on the hydrolysis of tetrabutyl titanate.
[0017] The mass ratio of MoS2 / NiO / TiO2 to lithium iron manganese phosphate particles in S4 is 2~3:1.
[0018] The stirring time in S4 is 24-30 hours; the temperature of the vacuum drying oven is 60-80℃, and the drying time is 1-2 hours.
[0019] In the technical solution of this invention, MoS2 and NiO nanoparticles are synthesized by hydrothermal reaction, and titanium dioxide nanoparticles are generated by the hydrolysis of tetrabutyl titanate. These nanoparticles are then co-coated on the surface of lithium manganese iron phosphate cathode material. By introducing MoS2 / NiO / TiO2 with good conductivity, the material's conductivity and ion diffusion rate are improved.
[0020] The beneficial effects of this invention are as follows:
[0021] 1. A MoS2 / NiO / TiO2 composite material was prepared through hydrothermal and hydrolysis reactions, marking the first time that the MoS2 / NiO / TiO2 composite material has been co-coated on the surface of lithium manganese iron phosphate cathode material. The semiconductor composite material coating on the material surface provides a large number of active sites, which is beneficial to improving the specific capacity of the battery. Furthermore, the composite of the three materials exhibits high conductivity and ion transport performance, which is beneficial to improving the energy density of the battery.
[0022] 2. The modified lithium manganese iron phosphate cathode material exhibits significantly improved conductivity and increased specific capacity. Attached Figure Description
[0023] Figure 1 The discharge specific capacity diagrams for Examples 1, 2, and 5 at 0.1C are shown. Detailed Implementation
[0024] This invention does not limit the scope of the invention, and those skilled in the art can make some modifications and improvements based on the above-described invention.
[0025] Example 1
[0026] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0027] (1) Weigh 0.2 g of nickel nitrate and 0.4 g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; mix 0.2 g of ammonium molybdate and 0.6 g of thiourea, add water, and sonicate for 30 min until the two are mixed to obtain molybdenum source mixture;
[0028] (2) The mixed solution obtained in (3) was transferred to a polytetrafluoroethylene hydrothermal reactor, and slowly heated to 180°C and kept at that temperature for 24 h. The resulting mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution. The mixture was then dried in a vacuum drying oven to obtain MoS2 and NiO solid particles.
[0029] (3) Weigh 0.25 g of tetrabutyl titanate, 0.2 g of MoS2 solid particles, and 0.2 g of NiO solid particles, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.5 mL of potassium chloride solution (0.1 M), continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain MoS2 / NiO / TiO2 solid particles;
[0030] (4) Weigh 0.3 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain MoS2 / NiO / TiO2 coated lithium iron manganese phosphate cathode material.
[0031] Example 2
[0032] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0033] (1) Weigh 0.2 g of Ni(NO3)2 solid, add 0.6 g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; mix 0.2 g of ammonium molybdate and 0.4 g of thiourea thoroughly, add water, and sonicate for 30 min until the two are mixed to obtain molybdenum source mixture;
[0034] (2) The mixed solution obtained in (1) was transferred to a polytetrafluoroethylene hydrothermal reactor, and slowly heated to 180°C and kept at that temperature for 24 h. The mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution. The mixture was then dried in a vacuum drying oven to obtain MoS2 and NiO solid particles.
[0035] (3) Weigh 0.25 g of tetrabutyl titanate, 0.2 g of MoS2 solid particles, and 0.3 g of NiO solid particles, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.5 mL (0.1 M) of potassium chloride solution, continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain MoS2 / NiO / TiO2 solid particles;
[0036] (4) Weigh 0.3 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain MoS2 / NiO / TiO2 coated lithium iron manganese phosphate cathode material.
[0037] Example 3
[0038] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0039] (1) Weigh 0.3g of Ni(NO3)2 solid, add 0.6g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; mix 0.2g of ammonium molybdate and 0.6g of thiourea, add water, and sonicate for 30 min until the two are mixed to obtain molybdenum source mixture;
[0040] (2) The mixed solution obtained in (1) was transferred to a polytetrafluoroethylene hydrothermal reactor, and slowly heated to 180°C and kept at that temperature for 24 h. The mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution. The mixture was then dried in a vacuum drying oven to obtain MoS2 and NiO solid particles.
[0041] (3) Weigh 0.25 g of tetrabutyl titanate, 0.3 g of MoS2 solid particles, and 0.2 g of NiO solid particles, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.6 mL (0.1 M) of potassium chloride solution, continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain MoS2 / NiO / TiO2 solid particles;
[0042] (4) Weigh 0.3 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain MoS2 / NiO / TiO2 coated lithium iron manganese phosphate cathode material.
[0043] Example 4
[0044] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0045] (1) Weigh 0.2 g of Ni(NO3)2 solid, add 0.5 g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; mix 0.2 g of ammonium molybdate and 0.6 g of thiourea thoroughly, add water, and sonicate for 30 min until the two are mixed to obtain molybdenum source mixture;
[0046] (2) The mixed solution obtained in (1) was transferred to a polytetrafluoroethylene hydrothermal reactor, and slowly heated to 180°C and kept at that temperature for 24 h. The mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution. The mixture was then dried in a vacuum drying oven to obtain MoS2 and NiO solid particles.
[0047] (3) Weigh 0.25 g of tetrabutyl titanate, 0.3 g of MoS2 solid particles, and 0.3 g of NiO solid particles, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.5 mL of potassium chloride solution (0.1 M), continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain MoS2 / NiO / TiO2 solid particles;
[0048] (4) Weigh 0.45 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain MoS2 / NiO / TiO2 coated lithium iron manganese phosphate cathode material.
[0049] Example 5
[0050] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0051] (1) Weigh 0.3 g of Ni(NO3)2 solid, add 0.9 g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; mix 0.2 g of ammonium molybdate and 0.4 g of thiourea, add water, and sonicate for 30 min until the two are mixed to obtain molybdenum source mixture;
[0052] (2) The mixed solution obtained in (1) was transferred to a polytetrafluoroethylene hydrothermal reactor, and slowly heated to 180°C and kept at that temperature for 24 h. The mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution. The mixture was then dried in a vacuum drying oven to obtain MoS2 and NiO solid particles.
[0053] (3) Weigh 0.25 g of tetrabutyl titanate, 0.2 g of MoS2 solid particles, and 0.2 g of NiO solid particles, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.5 mL of potassium chloride solution (0.1 M), continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain MoS2 / NiO / TiO2 solid particles;
[0054] (4) Weigh 0.45 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain MoS2 / NiO / TiO2 coated lithium iron manganese phosphate cathode material.
[0055] Comparative Example 1
[0056] This embodiment is basically the same as the steps in embodiment 1, except that: in step (1), 0.2 g of ammonium molybdate and 0.8 g of thiourea solution are weighed.
[0057] Comparative Example 2
[0058] This embodiment is basically the same as the steps in embodiment 1, except that: in step (1), 0.2 g of ammonium molybdate and 0.6 g of thiourea solution are weighed, and in step (2), the temperature is raised to 150°C.
[0059] Comparative Example 3
[0060] This embodiment is basically the same as the steps in embodiment 2, except that: in step (4), 0.1 g of tetrabutyl titanate is weighed and left to stand for 12 h.
[0061] Comparative Example 4
[0062] This embodiment is basically the same as the steps in embodiment 2, except that: in step (5), 0.6 g of MoS2 / NiO / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles are weighed.
[0063] Comparative Example 5
[0064] A method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, comprising the following steps:
[0065] (1) Weigh 0.3g of Ni(NO3)2 solid, add 0.9g of sodium hydroxide solid, stir, filter, and obtain nickel source mixture; add 0.2g of ammonium molybdate and 0.4g of thiourea to the nickel source mixture, mix thoroughly, add water, and sonicate for 30 min until well mixed to obtain a mixture containing nickel and molybdenum;
[0066] (2) The nickel and molybdenum mixture obtained in (1) was transferred to a polytetrafluoroethylene hydrothermal reactor, slowly heated to 180°C and kept at that temperature for 24 h; the mixture was centrifuged and washed three times at a speed of 12000 rpm / min, and then washed three times each with ultrapure water and isopropanol solution, and dried in a vacuum drying oven to obtain solid particles containing Mo and Ni.
[0067] (3) Weigh 0.25 g of tetrabutyl titanate and 0.4 g of solid particles containing Mo and Ni, add them to 50 mL of anhydrous ethanol, stir evenly, add 0.5 mL of potassium chloride solution (0.1 M), continue stirring, let stand for 24 h, wash with ultrapure water and ethanol, and vacuum dry for 24 h to obtain solid particles containing Mo / Ni / TiO2.
[0068] (4) Weigh 0.45 g of Mo / Ni / TiO2 solid particles and 0.15 g of lithium iron manganese phosphate particles, add 100 mL of ultrapure water, stir for 24 h, let stand, centrifuge and wash, and dry at 80 °C to obtain Mo / Ni / TiO2-coated lithium iron manganese phosphate cathode material. Comparative Example 6
[0069] This embodiment uses unmodified lithium manganese iron phosphate cathode material.
[0070] The obtained MoS2 / NiO / TiO2-coated lithium manganese iron phosphate was used as the positive electrode material of the battery and assembled into a coin cell for electrochemical performance testing. The discharge specific capacity and first-efficiency test results are shown in Table 1.
[0071] As shown in Table 1, the MoS2 / NiO / TiO2 coating on lithium manganese iron phosphate cathode material provided by this invention can effectively improve the conductivity of the material. Comparative Example 5 and Examples 1-4 all exhibit good discharge specific capacities, reaching 153.8-156.7 mAh / g at 0.1C rate, with an initial efficiency as high as 98.5%. The electrochemical performance of Comparative Examples 1-4 all decreased, indicating that the coating ratio of MoS2 / NiO / TiO2 particles should be appropriate. Too much or too little coating will affect its electronic conductivity, thus affecting its electrochemical performance. The amount of NiO solution should also be appropriate; too much will affect electron transport, thus affecting its electrochemical performance.
[0072] The discharge cycle life curve at 0.1C is as follows: Figure 1 As shown.
[0073] Depend on Figure 1 It can be seen that the MoS2 / NiO / TiO2 coating on lithium manganese iron phosphate cathode material provided by this invention can effectively improve the cycling performance of the material. After 300 cycles, the discharge specific capacity of Example 1 is 155.2 mAh / g, while that of Comparative Example 1 and Comparative Example 5 are 141.6 mAh / g and 139 mAh / g, respectively, indicating that MoS2 / NiO / TiO2 coating on lithium manganese iron phosphate has superior structural stability. The performance is shown in Table 1:
[0074]
[0075] The above description is merely a preferred embodiment of the present invention, but the present invention is not limited thereto. Various modifications or improvements can be made within the scope of the inventive concept, and all such modifications and improvements fall within the protection scope of the present invention. Therefore, the scope of protection of the present invention is defined by the appended claims.
Claims
1. A method for constructing a MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, characterized in that, Includes the following steps: S1: Mix nickel nitrate and sodium hydroxide thoroughly, add water, and sonicate until homogeneous to obtain a nickel source mixture; mix ammonium molybdate and thiourea solution thoroughly, add water, and sonicate until homogeneous to obtain a molybdenum source mixture; the mass ratio of nickel nitrate to sodium hydroxide is 1:2-3; the mass ratio of ammonium molybdate to thiourea is 1:2~3. S2: The nickel source mixture and molybdenum source mixture obtained in S1 are subjected to hydrothermal reaction to obtain NiO and MoS2 solid particles, respectively; the heating temperature of the hydrothermal reactor is 180-230℃, and the holding time is 10-24 h; S3: Tetrabutyl titanate, MoS2 solid particles, and NiO solid particles are placed in an alcohol solution, stirred evenly, and then salt is added. After standing, the mixture is washed and vacuum dried to obtain MoS2 / NiO / TiO2 solid particles. The mass ratio of tetrabutyl titanate, MoS2 solid particles, and NiO solid particles is 1-2.5:2~3:2~3. The salt can be any one of potassium chloride, sodium chloride, calcium chloride, and magnesium chloride. S4: Mix the obtained MoS2 / NiO / TiO2 solid particles with lithium iron manganese phosphate particles in a certain proportion, add water, stir and let stand, centrifuge and wash and then dry to obtain lithium iron manganese phosphate cathode material coated with MoS2 / NiO / TiO2 composite material; the mass ratio of MoS2 / NiO / TiO2 to lithium iron manganese phosphate particles is 2~3:1; the stirring time is 24-30h.
2. The method for modifying MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material according to claim 1, characterized in that: The temperature of the vacuum drying oven in S4 is 60-80℃, and the drying time is 1-2 hours.
3. A method for constructing a MoS2 / NiO / TiO2-coated lithium manganese iron phosphate cathode material, characterized in that, It was prepared using the modification method described in any one of claims 1-2.