Preparation method of ferromanganese selenide-based Prussian blue composite electrode material and application of ferromanganese selenide-based Prussian blue composite electrode material as positive electrode material in sodium-ion battery
By introducing selenium in the synthesis process of MnHCF and using vapor deposition method to process it, the capacity and stability of MnHCF in sodium ion batteries are solved, the conductivity and cycling performance are significantly improved, and higher energy density and cycling life are achieved.
Patent Information
- Application Number
- CN202411920730.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-01
AI Technical Summary
The actual capacity and cycle stability of ferromanganese Prussian Blue (MnHCF) in sodium ion batteries are poor, mainly due to its inherent low conductivity and Jahn-Teller effect, which leads to the easy dissolution of manganese 3+.
By introducing selenium during the synthesis of MnHCF, the MnHCF-Se composite electrode material was prepared, and the vapor deposition method was used to calcinate under an argon atmosphere, which improved the conductivity and structural stability of the material.
The conductivity of MnHCF is improved, the charge transfer of the redox center is promoted, the dissolution of manganese is inhibited, and the energy density and cycle life of the material is significantly improved. The actual capacity is increased from 105mA h·g-1 to 130mA h·g-1.
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Figure CN119735222A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of materials, and in particular relates to a method for preparing a manganese iron selenide-based Prussian blue composite electrode material and an application of the material as a positive electrode material in a sodium ion battery. Background Art
[0002] With the development of production technology, the scarcity and uneven distribution of lithium resources have become increasingly apparent, and the search for low-cost, resource-rich alternatives has become the focus of attention. In recent years, sodium-ion batteries have entered people's field of vision due to cheap, abundant and readily available sodium resources, and have become a choice for large-scale energy storage with broad development prospects. Among the many cathode materials, Prussian blue and its analogues have been widely studied due to their rich redox centers, flexible three-dimensional framework structures and ion channels, which allow sodium ions to be embedded / ejected during the charging and discharging process. Among them, manganese iron-based Prussian blue (MnHCF) has dual redox centers, which can theoretically store 2 Na per unit molecular weight. + , thus achieving 170mAh·g- 1 However, researchers gradually realized that MnHCF has the Jahn-Teller effect and that Mn 3+ The easy dissolution into the electrolyte and the inherent low conductivity of Prussian blue materials result in unsatisfactory actual capacity and cycle stability. Therefore, effective strategies need to be developed to improve the structural stability and conductivity of manganese-based Prussian blue positive electrode materials, so as to achieve sodium-ion batteries with high specific capacity and cycle stability. Summary of the invention
[0003] In order to solve the above problems, the present invention provides a method for preparing a MnHCF-Se composite material and application of the composite material as a positive electrode material in a sodium ion battery.
[0004] To achieve the above object, the technical solution adopted by the present invention is: a MnHCF-Se composite electrode material, the preparation method of which comprises the following steps:
[0005] Manganese acetate and dipotassium ethylenediaminetetraacetic acid are dissolved in deionized water to obtain solution A, potassium ferrocyanide is dissolved in deionized water to obtain solution B, solution A is added dropwise to solution B under stirring conditions, and the mixture is aged for 4 hours and then centrifuged to obtain Prussian blue MnHCF. Selenium powder and Prussian blue are mixed and ground, and then placed in a tube furnace for vapor deposition under argon atmosphere to obtain MnHCF-Se composite electrode material.
[0006] The above-mentioned MnHCF composite electrode material has a molar ratio of dipotassium ethylenediaminetetraacetic acid: manganese acetate: potassium ferrocyanide = 4:5:4.
[0007] The above-mentioned MnHCF-Se composite electrode material has a mass ratio of selenium powder:MnHCF=1:20.
[0008] The vapor deposition of the MnHCF-Se composite electrode material mentioned above refers to calcining in an argon atmosphere in a tubular furnace at a heating rate of 5°C per minute and maintaining the temperature at 250°C for 150 minutes.
[0009] The above-mentioned MnHCF-Se composite electrode material is used as a positive electrode in a sodium ion battery.
[0010] In the above application, the method for preparing the positive electrode sheet comprises the following steps:
[0011] After the above-mentioned MnHCF-Se composite electrode material is evenly mixed with a binder and a conductive material, a small amount of NMP is added as a solvent, mixed evenly, and then directly applied on a carbon-coated titanium foil substrate, dried in a vacuum drying oven, and taken out to obtain a positive electrode sheet coated with the MnHCF-Se composite electrode material.
[0012] In the above application, the binder is PVDF.
[0013] In the above application, the conductive material is Super-p.
[0014] In the above application, the mass ratio of MnHCF-Se composite electrode material: conductive material: binder is 7:2:1.
[0015] In the above application, the above positive electrode sheet is used as the positive electrode, the sodium sheet is used as the negative electrode, and the electrolyte is NaPF6 electrolyte NP-005 to obtain a sodium ion battery.
[0016] The beneficial effects of the present invention are:
[0017] 1. By introducing selenium during the synthesis process, the conductivity of MnHCF is effectively improved, which promotes the 2+ / Mn 3+ , Fe 2+ / Fe 3+ The charge transfer between the two redox centers also helps to inhibit manganese dissolution, thereby preparing advanced Prussian blue positive electrode materials for sodium-ion batteries, improving the energy density and cycle life of the material.
[0018] 2. The synthesis process and assembly process are simple, easy to operate and control, and suitable for continuous large-scale production.
[0019] 3. After modification, the capacity of the electrode material is increased from 105mA h·g -1 Increased to 130mAh·g -1 . BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 is the XRD spectrum of MnHCF-Se prepared in Example 1.
[0021] Figure 2 This is the TEM spectrum of MnHCF-Se prepared in Example 1.
[0022] Figure 3 This is the cyclic voltammetry curve of MnHCF-Se prepared in Example 1.
[0023] Figure 4 This is the impedance diagram of MnHCF-Se prepared in Example 1. DETAILED DESCRIPTION
[0024] The technical solution of the present invention is further described below, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.
[0025] Example 1
[0026] (I) The preparation method of MnHCF-Se is as follows:
[0027] 0.98g of manganese acetate and 1.61g of dipotassium ethylenediaminetetraacetate were dissolved in 50ml of deionized water to obtain solution A, 1.66g of potassium ferrocyanide was dissolved in 50ml of deionized water to obtain solution B, solution A was added dropwise to solution B under stirring, aged for 4h, centrifuged and washed three times with deionized water, and vacuum dried at 60°C for 12h to obtain MnHCF. 5mg of selenium powder was mixed with 100mg of MnHCF and ground, then placed in a tube furnace, heated at a heating rate of 5°C per minute under an argon atmosphere, and kept at a constant temperature of 250°C for 150min to obtain MnHCF-Se.
[0028] (II) Comparative Example: The preparation method of MnHCF is as follows:
[0029] 0.98 g of manganese acetate and 1.61 g of dipotassium ethylenediaminetetraacetate were dissolved in 50 ml of deionized water to obtain solution A, and 1.66 g of potassium ferrocyanide was dissolved in 50 ml of deionized water to obtain solution B. Solution A was added dropwise to solution B under stirring, aged for 4 h, centrifuged and washed three times with deionized water, and vacuum dried at 60 ° C for 12 h to obtain MnHCF.
[0030] (III) Detection
[0031] Figure 1 is the XRD spectrum of MnHCF-Se prepared in this example. Figure 1 It can be seen that selenium does not affect the crystal form of Prussian blue. Figure 2This is the TEM spectrum of MnHCF-Se. Figure 2 It can be seen that the prepared MnHCF-Se has a typical cubic structure. Figure 3 This is the cyclic voltammetry curve of MnHCF-Se. Figure 3 It can be seen that the area enclosed by MnHCF-Se is significantly larger than that of MnHCF, which indicates that the capacity of MnHCF-Se is greater than that of MnHCF. Figure 4 is the electrochemical impedance diagram of MnHCF and MnHCF-Se. Figure 4 It can be seen that the conductivity of MnHCF-Se is significantly higher than that of MnHCF.
[0032] Example 2 Preparation of MnHCF-Se
[0033] 0.98g manganese acetate and 1.61g ethylenediaminetetraacetic acid dipotassium salt were dissolved in 50ml deionized water to obtain solution A, 1.66g potassium ferrocyanide was dissolved in 50ml deionized water to obtain solution B, solution A was added dropwise to solution B under stirring, aged for 4h, centrifuged and washed three times with deionized water, and vacuum dried at 60℃ for 12h to obtain MnHCF. 3.5mg selenium powder was mixed with 100mg MnHCF and ground, then placed in a tube furnace, heated at a heating rate of 5℃ per minute under argon atmosphere, and kept at 250℃ for 150min to obtain MnHCF-Se.
[0034] Example 3 Preparation of MnHCF-Se
[0035] 0.98g manganese acetate and 1.61g dipotassium salt of ethylenediaminetetraacetic acid were dissolved in 50ml deionized water to obtain solution A, 1.66g potassium ferrocyanide was dissolved in 50ml deionized water to obtain solution B, solution A was added dropwise to solution B under stirring, aged for 4h, centrifuged and washed three times with deionized water, and vacuum dried at 60℃ for 12h to obtain MnHCF. 7.5mg selenium powder was mixed with 100mg MnHCF and ground, then placed in a tube furnace, heated at a heating rate of 5℃ per minute under argon atmosphere, and kept at 250℃ for 150min to obtain MnHCF-Se.
[0036] Example 4 Preparation of MnHCF-Se
[0037] 0.98g of manganese acetate and 1.61g of dipotassium ethylenediaminetetraacetate were dissolved in 50ml of deionized water to obtain solution A, 1.66g of potassium ferrocyanide was dissolved in 50ml of deionized water to obtain solution B, solution A was added dropwise to solution B under stirring, aged for 4h, centrifuged and washed three times with deionized water, and vacuum dried at 60°C for 12h to obtain MnHCF. 10mg of selenium powder and 100mg of MnHCF were mixed and ground and placed in a tube furnace, heated at a heating rate of 5°C per minute under an argon atmosphere, and kept at a constant temperature of 250°C for 150min to obtain MnHCF-Se.
[0038] Example 5 Preparation of negative electrode material
[0039] Commercially available round sodium sheets with a diameter of 12 mm were purchased as negative electrode sheets.
[0040] Example 6 Preparation of Sodium Ion Battery
[0041] 1) Preparation of positive electrode: After the MnHCF-Se composite electrode material prepared in Example 1 is uniformly mixed with PVDF and Super-p, a small amount of NMP is added as a solvent, and after uniform mixing, it is directly applied on the substrate carbon-coated titanium foil, placed in a vacuum drying oven, dried and taken out to obtain a positive electrode sheet coated with MnHCF-Se;
[0042] 2) The positive electrode sheet prepared in step 1) is used as the positive electrode, the negative electrode material prepared in Example 5 is used as the negative electrode, and NaPF6 electrolyte (NP-005) is selected as the electrolyte to obtain a sodium ion battery and perform electrochemical testing.
[0043] Example 7 Preparation of Sodium Ion Battery
[0044] 1) Preparation of positive electrode: After the MnHCF-Se composite electrode material prepared in Example 2 is mixed with PVDF and Super-p, a small amount of NMP is added as a solvent, mixed evenly, and then directly applied on the substrate carbon-coated titanium foil, placed in a vacuum drying oven and dried, and then taken out to obtain a positive electrode sheet coated with MnHCF-Se;
[0045] 2) The positive electrode sheet prepared in step 1) is used as the positive electrode, the negative electrode material prepared in Example 5 is used as the negative electrode, and NaPF6 electrolyte (NP-005) is selected as the electrolyte to obtain a sodium ion battery and perform electrochemical testing.
[0046] Example 8 Preparation of Sodium Ion Battery
[0047] 1) Preparation of positive electrode: After the MnHCF-Se composite electrode material prepared in Example 3 is mixed with PVDF and Super-p, a small amount of NMP is added as a solvent, mixed evenly, and then directly applied on the substrate carbon-coated titanium foil, placed in a vacuum drying oven and dried, and then taken out to obtain a positive electrode sheet coated with MnHCF-Se;
[0048] 2) The positive electrode sheet prepared in step 1) is used as the positive electrode, the negative electrode material prepared in Example 5 is used as the negative electrode, and NaPF6 electrolyte (NP-005) is selected as the electrolyte to obtain a sodium ion battery and perform electrochemical testing.
[0049] Example 9 Preparation of Sodium Ion Battery
[0050] 1) Preparation of positive electrode: After the MnHCF-Se composite electrode material prepared in Example 4 is mixed with PVDF and Super-p, a small amount of NMP is added as a solvent, mixed evenly, and then directly applied on the substrate carbon-coated titanium foil, placed in a vacuum drying oven and dried, and then taken out to obtain a positive electrode sheet coated with MnHCF-Se;
[0051] 2) The positive electrode sheet prepared in step 1) is used as the positive electrode, the negative electrode material prepared in Example 5 is used as the negative electrode, and NaPF6 electrolyte (NP-005) is selected as the electrolyte to obtain a sodium ion battery and perform electrochemical testing.
[0052] According to the four sodium ion batteries assembled according to the above Examples 6 to 9, we obtained that Example 6 has the best electrochemical performance, at a current density of 0.02 A·g -1 The specific capacity is 130m Ah·g -1 .like Figure 2 As shown, in Example 6, the distribution of Se in the MnHCF-Se composite material formed by selenium: Prussian blue = 1:20 is more uniform, and the Prussian blue is not completely wrapped to affect the insertion / extraction of sodium ions. By improving the conductivity and inhibiting the dissolution of manganese, a sodium ion battery with excellent rate performance and cycle performance is obtained.
Claims
1. A MnHCF-Se composite electrode material, characterized in that: The preparation method thereof comprises the following steps: Manganese acetate and dipotassium ethylenediaminetetraacetic acid are dissolved in deionized water to obtain solution A, potassium ferrocyanide is dissolved in deionized water to obtain solution B, solution A is added dropwise to solution B under stirring conditions, and the mixture is aged for 4 hours and then centrifuged to obtain Prussian blue MnHCF. Selenium powder and Prussian blue are mixed and ground, and then placed in a tube furnace for vapor deposition under argon atmosphere to obtain MnHCF-Se composite electrode material.
2. A MnHCF composite electrode material according to claim 1, characterized in that: In molar ratio, dipotassium ethylenediaminetetraacetic acid: manganese acetate: potassium ferrocyanide = 4:5:
4.
3. A MnHCF-Se composite electrode material according to claim 1, characterized in that: By mass ratio, selenium powder:MnHCF=1:
20.
4. The MnHCF-Se composite electrode material according to claim 1, characterized in that: The vapor deposition process is carried out in an argon atmosphere in a tube furnace at a heating rate of 5°C per minute and maintained at 250°C for 150 minutes.
5. Use of a MnHCF-Se composite electrode material as claimed in any one of claims 1 to 4 as a positive electrode sheet in a sodium ion battery.
6. The use according to claim 5, characterized in that: The method for preparing the positive electrode sheet comprises the following steps: After uniformly mixing any one of the MnHCF-Se composite electrode materials of claims 1-4 with a binder and a conductive material, a small amount of NMP is added as a solvent, and after uniform mixing, the mixture is directly applied on a carbon-coated titanium foil substrate, dried in a vacuum drying oven, and taken out to obtain a positive electrode sheet coated with the MnHCF-Se composite electrode material.
7. The use according to claim 6, characterized in that: The binder is PVDF.
8. The use according to claim 6, characterized in that: The conductive material is Super-p.
9. The use according to claim 6, characterized in that: In terms of mass ratio, MnHCF-Se composite electrode material: conductive material: binder = 7:2:
1.
10. The use according to claim 6, characterized in that: The positive electrode sheet obtained in claim 6 is used as the positive electrode, the sodium sheet is used as the negative electrode, and the electrolyte is NaPF6 electrolyte NP-005 to obtain a sodium ion battery.