A sub-micron Ti2Nb 10 O 29 and a preparation method and application thereof
The synthesis of submicron-sized Ti2Nb10O29 via solution combustion solves the problem of synthesizing submicron-sized materials in existing technologies, achieving high capacity and rapid lithium-ion diffusion, and improving the high-rate performance and long-cycle stability of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-19
- Publication Date
- 2026-03-24
AI Technical Summary
Existing technologies make it difficult to synthesize submicron-sized Ti2Nb10O29, which limits its application and performance in lithium-ion batteries, especially in terms of high-rate performance and structural stability.
Submicron-sized Ti2Nb10O29 was synthesized by solution combustion. The reaction between tetrabutyl titanate and niobium oxalate was promoted by glycine and concentrated nitric acid, and the reaction process was controlled to obtain high-quality submicron-sized materials.
The prepared submicron-sized Ti2Nb10O29 material has higher capacity and faster lithium-ion diffusion coefficient, which significantly improves the rate performance of lithium-ion anodes and maintains good long-cycle performance at high rates.
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Figure CN117342612B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new energy material preparation technology, and particularly to a submicron-sized Ti2Nb 10 O 29 Its preparation methods and applications. Background Technology
[0002] Niobium-based oxides not only possess high theoretical lithium storage capacity but also have safe operating potentials (>1V), making them promising anode materials for lithium-ion batteries (LIBs). Within the niobium-based oxide family, TNO involves single-electron transfer from titanium (Ti). 4+ -Ti 3+ ) and niobium's two-electron transfer (Nb 5+ -Nb 3+ ) Charge transfer mechanism, with 396mAh g -1 Ti has a high theoretical lithium storage capacity. 4+ / Ti 3+ 、Nb 5+ / Nb 4+ 、Nb 4+ / Nb 3+ The operating potential of the redox couple is between 1.0 and 2.0 V, which is higher than the reduction voltage of some organic electrolytes (0.8 V vs. Li / Li). + Therefore, the formation of lithium dendrites and the solid electrolyte interface layer can be prevented, ensuring the safe operation of LIBs. The TNO shear-type ReO3 structure consists of octahedrons shared by corners and edges, arranged in a 3×4×∞ pattern. The edge-splitting structure enhances the structural stability of TNO during charge-discharge cycles.
[0003] Currently reported methods for synthesizing nanoscale TNO mainly include sol-gel, hydrothermal, and electrospinning techniques. Existing preparation methods primarily synthesize TNO in nano and micrometer sizes. Micrometer-sized TNO (m-TNO) is mainly synthesized using industrial TiO2 and Nb2O5 powders as raw materials in a solid-state process. Compared to m-TNO, nanoscale materials often exhibit superior rate performance and higher average diffusion coefficients due to their tightly packed structure. However, nanoscale samples typically have lower packing density and lower volumetric energy density, and the enlarged interface between the electrode and electrolyte caused by nanoscale particles can lead to severe side reactions. Submicron-sized s-TNO has a larger specific surface area and smaller, more uniform particles than m-TNO, which can shorten the lithium-ion migration distance and possess excellent high-rate storage performance. Compared to nanoscale TNO, it effectively avoids agglomeration and low coulombic efficiency caused by small particle size. However, existing preparation methods mainly synthesize nano and micrometer-sized TNO, which greatly limits the development and application of TNO. Summary of the Invention
[0004] In view of this, the present invention proposes a submicron-scale Ti2Nb 10 O 29 This invention relates to its preparation method and applications. It describes the synthesis of submicron-sized Ti₂Nb using a solution combustion method. 10 O 29 (abbreviated as s-TNO) has higher capacity and a faster lithium-ion diffusion coefficient, which significantly improves the rate performance of lithium-ion anodes.
[0005] The technical solution of this invention is implemented as follows:
[0006] A submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0007] S1. Add tetrabutyl titanate to a mixed solution of concentrated nitric acid and deionized water, stir to dissolve and obtain a tetrabutyl titanate solution.
[0008] S2. Add niobium oxalate and glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir to mix well to obtain a mixed solution.
[0009] S3. Transfer the mixed solution from step S2 to a crucible, heat it in a muffle furnace, and then anneal it to obtain submicron-sized Ti2Nb. 10 O 29 .
[0010] Furthermore, the submicron-sized Ti2Nb 10 O 29 The raw materials include the following weight proportions: tetrabutyl titanate 0.250-0.300g, niobium oxalate 2.000-2.500g, and glycine 1.500-2.500g.
[0011] Furthermore, in step S1 above, the mass ratio of tetrabutyl titanate to concentrated nitric acid is 1:9 to 15; the mass concentration of concentrated nitric acid is 68 to 70%; and the volume ratio of concentrated nitric acid to deionized water is 1:1 to 3.
[0012] Furthermore, in step S2 above, the stirring speed is 100-300 r / min and the time is 1-3 h.
[0013] Furthermore, in step S3 above, the heating temperature of the muffle furnace is 700-900℃, and the heating time is 20-40 minutes.
[0014] Furthermore, in step S3 above, the heating annealing temperature is 1000-1200℃, the heating rate is 4-5℃·min-1, and the processing time is 2-4h.
[0015] Furthermore, this method can also be extended to synthesize other niobium-based oxides that can be used as high-rate lithium-ion anodes, such as barium niobium oxide, iron niobium oxide, nickel niobium oxide, molybdenum niobium oxide, etc.
[0016] Submicron Ti2Nb 10 O 29 Application in the preparation of TNO working electrodes.
[0017] Furthermore, the TNO working electrode comprises the following percentage of raw materials: submicron-sized Ti2Nb 10 O 29 Raw materials: 60-80 wt%, carbon black: 10-30 wt%, polyvinylidene fluoride: 5-15 wt%.
[0018] Furthermore, the TNO working electrode fabrication process involves: preparing submicron-sized Ti2Nb... 10 O 29 The raw materials, carbon black and polyvinylidene fluoride are mixed to obtain mixture I. Then, N-methyl-2-pyrrolidone is added to mixture I to obtain mixture II. Then, mixture II is coated on copper foil and dried overnight in a vacuum oven at 70-90°C to obtain the TNO working electrode.
[0019] Furthermore, the mass ratio of mixture I to N-methyl-2-pyrrolidone is 0.07:0.3-0.6; the mass ratio of copper foil to mixture II is 6.74:1.6-1.8.
[0020] Furthermore, the TNO working electrode is used in a half-cell.
[0021] Furthermore, the half-cell assembly materials are as follows: the electrolyte is prepared by mixing ethylene carbonate and diethyl carbonate in a mass ratio of 1:1; the glass fiber membrane GF / D is used as the membrane; the TNO working electrode is used as the working electrode; and the lithium foil is used as the counter electrode.
[0022] Compared with the prior art, the beneficial effects of the present invention are:
[0023] 1) The solution combustion method used in this invention is effective in preparing submicron-sized Ti2Nb. 10 O 29 The reaction between tetrabutyl titanate and niobium oxalate is effectively promoted by glycine and concentrated nitric acid, resulting in higher quality submicron-sized Ti2Nb. 10 O 29 Materials: Glycine not only acts as a fuel but also forms complexes with metal ions, promoting their solubility and preventing partial precipitation during rapid water evaporation. The use of concentrated nitric acid effectively prevents the hydrolysis of tetrabutyl titanate in deionized water.
[0024] 2) The preparation process of this invention is reasonable and can effectively control the reaction between tetrabutyl titanate and raw materials such as niobium oxalate, forming submicron-sized Ti2Nb with better crystallinity. 10 O 29 Material.
[0025] 3) The solution combustion method of the present invention synthesizes TNO with smaller size than the traditional solid phase method; the solution combustion method of the present invention synthesizes submicron TNO with higher capacity (50 mAh / g) than the micron TNO synthesized by the traditional solid phase method, and has a faster lithium ion diffusion coefficient, which significantly improves the rate performance.
[0026] 4) The submicron TNO of the present invention has a higher pseudocapacitance than the micron TNO synthesized by the traditional solid-state method. Furthermore, the submicron TNO has superior long-cycle performance, and its capacity can still be maintained at 77.9% after 10,000 cycles at high rates. Attached Figure Description
[0027] Figure 1 XRD patterns for the synthesis of s-TNO by solution combustion and the synthesis of m-TNO by solid phase.
[0028] Figure 2 The charge-discharge curves are for solid-phase synthesis of m-TNO.
[0029] Figure 3 The charge-discharge curves for the synthesis of s-TNO by combustion of solution are shown.
[0030] Figure 4 Rate performance for solution combustion synthesis of s-TNO and solid-phase synthesis of m-TNO.
[0031] Figure 5 Long-cycle performance of solution combustion synthesis of s-TNO and solid-phase synthesis of m-TNO.
[0032] Figure 6 Pseudocapacitive contribution diagram for solid-phase synthesis of m-TNO at a scan rate of 5 mV / s.
[0033] Figure 7 Pseudocapacitive contribution diagram for solid-phase synthesis of s-TNO at a scan rate of 5 mV / s. Detailed Implementation
[0034] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.
[0035] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0036] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.
[0037] Example 1
[0038] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0039] S1. Add 0.272g of tetrabutyl titanate to a mixed solution containing 2ml of concentrated nitric acid with a mass concentration of 68% and 4ml of deionized water, stir to dissolve and obtain a tetrabutyl titanate solution.
[0040] S2. Add 2.152 g of niobium oxalate and 2.000 g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 200 r / min for 2 h to obtain a mixed solution.
[0041] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 800°C for 30 min, then heat at 1100°C at a heating rate of 5°C / min. -1 Submicron-sized Ti2Nb was obtained by annealing for 3 hours. 10 O 29 .
[0042] Comparative Example 1
[0043] Compared with Example 1, this comparative example uses a solid-state method to synthesize micron-sized TNO (m-TNO).
[0044] 0.1 g of TiO2 and 0.83 g of Nb2O5 were mixed into 5 ml of ethanol to obtain a mixture. The mixture was continuously mixed using a solder paste machine to obtain a powder. The powder was then subjected to a heat treatment process in air at 1100°C at a rate of 5°C·min. -1 The micron-sized TNO sample (m-TNO) was prepared by heating at a certain rate for 20 h.
[0045] The micron-sized TNO sample (m-TNO) prepared in this comparative example was compared with the submicron-sized Ti2Nb sample prepared in Example 1. 10 O 29 (s-TNO) was used for performance testing and comparison. The test results are as follows: Figure 1-7 As shown.
[0046] The solution combustion method of this invention synthesizes TNO with smaller size compared to the traditional solid-phase method; the solution combustion method of this invention synthesizes submicron TNO with a higher capacity (50 mAh / g) than the micron TNO synthesized by the traditional solid-phase method, and has a faster lithium-ion diffusion coefficient, significantly improving rate performance.
[0047] Example 2
[0048] This submicron-sized Ti2Nb 10O 29 The preparation method includes the following steps:
[0049] S1. Add 0.300g of tetrabutyl titanate to a mixed solution containing 2ml of concentrated nitric acid with a mass concentration of 69% and 4ml of deionized water, stir to dissolve and obtain a tetrabutyl titanate solution.
[0050] S2. Add 2.500g of niobium oxalate and 2.000g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 200r / min for 2h to obtain a mixed solution.
[0051] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 700°C for 20 min, then heat at 1000°C at a heating rate of 4°C·min. -1 Submicron-sized Ti2Nb was obtained by annealing for 4 hours. 10 O 29 .
[0052] This embodiment yields submicron-sized Ti2Nb 10 O 29 Performance and submicron-sized Ti2Nb prepared in Example 1 10 O 29 Similar performance.
[0053] Example 3
[0054] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0055] S1. Add 0.250g of tetrabutyl titanate to a mixed solution of 2ml concentrated nitric acid and 4ml deionized water with a mass concentration of 70%, and stir to dissolve to obtain a tetrabutyl titanate solution.
[0056] S2. Add 1.978 g of niobium oxalate and 1.838 g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 300 r / min for 1 h to obtain a mixed solution.
[0057] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 900°C for 40 min, then heat at 1200°C at a heating rate of 4°C·min. -1 Submicron-sized Ti2Nb was obtained by annealing for 2 hours. 10 O 29 .
[0058] Submicron Ti2Nb 10 O 29In the preparation of TNO working electrodes, submicron-sized Ti2Nb, the raw material for TNO working electrodes, is weighed according to the following proportions. 10 O 29 The raw materials are 70 wt% carbon black, 20 wt% polyvinylidene fluoride, and 10 wt% polyvinylidene fluoride. The preparation process of this TNO working electrode is as follows: submicron-sized Ti2Nb 10 O 29 The raw materials, carbon black, and polyvinylidene fluoride are mixed to obtain mixture I. Then, mixture I is added to N-methyl-2-pyrrolidone for mixing to obtain mixture II. The mass ratio of mixture I to N-methyl-2-pyrrolidone is 0.07:0.5. Then, mixture II is coated on copper foil and dried overnight in a vacuum oven at 80°C to obtain the TNO working electrode, which is 6.74 mg of copper foil loaded with 1.6 to 1.8 mg of mixture II.
[0059] The submicron-sized Ti2Nb obtained in this embodiment 10 O 29 The performance is similar to that of Example 1, while the submicron-sized Ti2Nb obtained in this example... 10 O 29 When used in the TON working electrode, it enables the battery to have good performance.
[0060] Example 4
[0061] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0062] S1. Add 0.30g of tetrabutyl titanate to a mixed solution of 2ml concentrated nitric acid and 4ml deionized water with a mass concentration of 70%, and stir to dissolve to obtain a tetrabutyl titanate solution.
[0063] S2. Add 2.50 g of niobium oxalate and 2.50 g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 300 r / min for 1 h to obtain a mixed solution.
[0064] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 800°C for 35 min, then heat at 1100°C at a heating rate of 4°C / min. -1 Submicron-sized Ti2Nb was obtained by annealing for 4 hours. 10 O 29 .
[0065] Submicron Ti2Nb 10 O 29 In the preparation of TNO working electrodes, submicron-sized Ti2Nb, the raw material for TNO working electrodes, is weighed according to the following proportions. 10 O29 The raw materials are 60 wt% carbon black, 25 wt% polyvinylidene fluoride, and 15 wt% polyvinylidene fluoride. The preparation process of this TNO working electrode is as follows: submicron-sized Ti2Nb 10 O 29 The raw materials, carbon black, and polyvinylidene fluoride are mixed to obtain mixture I. Then, mixture I is added to N-methyl-2-pyrrolidone for mixing to obtain mixture II. The mass ratio of mixture I to N-methyl-2-pyrrolidone is 0.07:0.6. Then, mixture II is coated on copper foil and dried overnight in a vacuum oven at 70°C to obtain the TNO working electrode, which is 6.74 mg of copper foil loaded with 1.6 to 1.8 mg of mixture II.
[0066] The submicron-sized Ti2Nb obtained in this embodiment 10 O 29 The performance, as well as the performance when applied to the TON working electrode, is similar to that of Example 3.
[0067] Comparative Example 2
[0068] Compared to Example 1, this comparative example does not contain glycine. Specifically:
[0069] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0070] S1. Add 0.272g of tetrabutyl titanate to a mixed solution containing 2ml of concentrated nitric acid with a mass concentration of 68% and 4ml of deionized water, stir to dissolve and obtain a tetrabutyl titanate solution.
[0071] S2. Add 2.152 g of niobium oxalate to the tetrabutyl titanate solution obtained in step S1 above, and stir at 200 r / min for 2 h to obtain a mixed solution.
[0072] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 800°C for 30 min, then heat at 1100°C at a heating rate of 5°C / min. -1 Submicron-sized Ti2Nb was obtained by annealing for 3 hours. 10 O 29 .
[0073] In this comparative example, glycine was not added during the preparation process. Glycine, used as fuel, undergoes significant temperature changes during combustion, exhibiting very high heating and cooling rates. This makes it highly likely that non-equilibrium or metastable phases will appear in the product, resulting in higher product activity. The sample without added glycine led to agglomeration during subsequent heating and annealing, resulting in larger particle sizes and reduced capacity.
[0074] Comparative Example 3
[0075] Compared with Example 1, this comparative example prepared submicron-sized Ti2Nb 10 O 29 The processes are different. Details are as follows:
[0076] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0077] S1. Add 0.272g of tetrabutyl titanate to a mixed solution containing 2ml of concentrated nitric acid with a mass concentration of 68% and 4ml of deionized water, stir to dissolve and obtain a tetrabutyl titanate solution.
[0078] S2. Add 2.152 g of niobium oxalate and 2.000 g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 400 r / min for 1 h to obtain a mixed solution.
[0079] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 600°C for 50 min, then heat at 900°C at a rate of 3°C / min. -1 Submicron-sized Ti2Nb was obtained by annealing for 5 hours. 10 O 29 .
[0080] In this comparative example, the heating and annealing temperatures in step S3 are different. The excessively low heating and annealing temperatures result in slightly poor crystallinity and also lead to a decline in the long-cycle performance of s-TNO.
[0081] Comparative Example 4
[0082] Compared to Example 1, this comparative example did not contain concentrated nitric acid during the preparation process. Specifically:
[0083] This submicron-sized Ti2Nb 10 O 29 The preparation method includes the following steps:
[0084] S1. Add 0.272g of tetrabutyl titanate to 4ml of a mixed solution of deionized water and stir to dissolve to obtain a tetrabutyl titanate solution.
[0085] S2. Add 2.152 g of niobium oxalate and 2.000 g of glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir at 200 r / min for 2 h to obtain a mixed solution.
[0086] S3. Transfer the mixed solution from step S2 to a crucible, place it in a muffle furnace and heat at 800°C for 30 min, then heat at 1100°C at a heating rate of 5°C / min.-1 Submicron-sized Ti2Nb was obtained by annealing for 3 hours. 10 O 29 .
[0087] In this comparative example, concentrated nitric acid was not added during the preparation process, resulting in Ti... 4+ / Nb 5+ Hydrolysis occurs in deionized water, which prevents tetrabutyl titanate and niobium oxalate from forming a homogeneous mixed solution, resulting in partial precipitation and causing the final synthesized sample to be not a pure phase TNO.
[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A submicron-sized Ti2Nb 10 O 29 The preparation method of the [method] is characterized by, Includes the following steps: S1. Add tetrabutyl titanate to a mixed solution of concentrated nitric acid and deionized water, stir to dissolve and obtain a tetrabutyl titanate solution. S2. Add niobium oxalate and glycine to the tetrabutyl titanate solution obtained in step S1 above, and stir to mix well to obtain a mixed solution. S3. Transfer the mixed solution from step S2 to a crucible, heat it in a muffle furnace, and then anneal it to obtain submicron-sized Ti2Nb. 10 O 29 The annealing temperature is 1000~1200℃, and the heating rate is 4~5℃·min. -1 The processing time is 2-4 hours.
2. The submicron-sized Ti₂Nb according to claim 1 10 O 29 The preparation method of the [method] is characterized by, The submicron-sized Ti2Nb 10 O 29 The raw materials include the following weight proportions: tetrabutyl titanate 0.250~0.300g, niobium oxalate 2.000~2.500g, and glycine 1.500~2.500g.
3. The submicron-sized Ti2Nb according to claim 1 10 O 29 In the preparation method, in step S1 above, the mass ratio of tetrabutyl titanate to concentrated nitric acid is 1:9~15; the mass concentration of concentrated nitric acid is 68~70%; and the volume ratio of concentrated nitric acid to deionized water is 1:1~3.
4. The submicron-sized Ti₂Nb according to claim 1 10 O 29 The preparation method of the [method] is characterized by, In step S2 above, the stirring speed is 100~300 r / min and the time is 1~3 h.
5. The submicron-sized Ti₂Nb according to claim 1 10 O 29 The preparation method of the [method] is characterized by, In step S3 above, the heating temperature of the muffle furnace is 700~900℃, and the heating time is 20~40min.
6. The submicron-sized Ti2Nb according to any one of claims 1-5 10 O 29 Application in the preparation of TNO working electrodes.
7. The application according to claim 6, characterized in that, The TNO working electrode comprises the following percentage of raw materials: submicron Ti2Nb 10 O 29 Raw materials: 60-80 wt%, carbon black: 10-30 wt%, polyvinylidene fluoride: 5-15 wt%.
8. The application according to claim 7, characterized in that, The TNO working electrode is prepared by: submicron-sized Ti2Nb 10 O 29 The raw materials, carbon black and polyvinylidene fluoride are mixed to obtain mixture I. Then, N-methyl-2-pyrrolidone is added to mixture I to obtain mixture II. Then, mixture II is coated on copper foil and dried overnight in a vacuum oven at 70~90℃ to obtain the TNO working electrode.
9. The application according to claim 8, characterized in that, The mass ratio of mixture I to N-methyl-2-pyrrolidone is 0.07:0.3~0.6; the mass ratio of copper foil-loaded mixture II is 6.74:1.6~1.8.