A method for preparing manganese dioxide co-doped with organic amine and phosphorus
By using layered manganese dioxide materials co-doped with organic amines and phosphorus, the structural instability and ion diffusion problems of manganese dioxide cathode materials in zinc-ion batteries were solved, resulting in a significant improvement in high-performance electrochemical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- EAST CHINA UNIV OF TECH
- Filing Date
- 2026-02-22
- Publication Date
- 2026-05-29
AI Technical Summary
Existing manganese dioxide cathode materials suffer from structural instability, slow ion diffusion kinetics, and manganese dissolution issues in zinc-ion batteries, leading to severe capacity decay and limited cycle life.
Layered manganese dioxide materials co-doped with organic amines and phosphorus are used to synergistically improve ion diffusion kinetics, electronic conductivity and structural stability through a dual regulation strategy of organic molecule intercalation and non-metallic element doping.
It significantly improved the electrochemical performance of manganese dioxide, enhanced its specific capacity and rate performance, and improved the cycling stability of the material.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of materials preparation technology, specifically to a method for preparing modified manganese dioxide, which is particularly suitable for aqueous zinc-ion battery cathode materials. Background Technology
[0002] Manganese dioxide (MnO2) cathodes benefit from high operating voltage and considerable specific capacity (theoretical specific capacity 308 mAh·g). -1 With its advantages such as high density and density, manganese dioxide is considered a highly promising candidate material for zinc-ion batteries. However, it suffers from structural instability, slow ion diffusion kinetics, and manganese dissolution during charge and discharge, leading to significant capacity decay and limited cycle life, severely hindering its practical application. Studies have shown that appropriate interlayer spacing is beneficial for ion storage. Doping modification can effectively control the interlayer spacing of manganese dioxide, thereby stabilizing its crystal structure during ion insertion / extraction.
[0003] Currently, the most common doping elements are metal ions (such as K). + Na + Al 3+ (etc.). For example, Zhang and Yi's research group used Fe... 3+ and Co 2+ Doped and modified manganese dioxide cathodes were applied to aqueous zinc-ion batteries, and it was found that metal cation doping can broaden the range of Zn... 2+ and H + The transport channels are improved, the diffusion barrier is reduced, and the rate performance is enhanced. Doped metal ions can form MO bonds with oxygen, which enhances structural stability and optimizes electrochemical performance by changing the local charge distribution (Advanced Functional Materials, 2025, 35(20): 2423755).
[0004] Furthermore, non-metallic element doping has also been shown to significantly improve the electronic structure of transition metal oxides. For example, selenium (Se) and phosphorus (P) co-doped MnO2 nanorods exhibit excellent electrochemical performance when used as the cathode in aqueous zinc-ion batteries. The substitution of highly electronegative O with low-electronyl Se and P can adjust the electronic structure of MnO2 and balance H+. + / Zn 2+ The adsorption-desorption process accelerates the reaction kinetics (Chemical Engineering Journal, 2024, 484, 149525).
[0005] In recent years, organic molecule intercalation modification strategies have also attracted widespread attention. Compared with inorganic ions, organic molecules (such as ethylenediamine, urea, and polyaniline) have advantages such as tunable molecular size and abundant functional groups. The amino groups in organic amines can form stable coordination bonds with the MnO2 layer, while simultaneously expanding the interlayer spacing, thus providing Zn.2+ Provides a wider diffusion channel (Small, 2024, 20(42): 2402811).
[0006] While the aforementioned methods can improve the zinc storage performance of manganese dioxide, none of them fully address its existing problems. Therefore, this invention proposes a layered manganese dioxide material co-doped with organic amines and phosphorus. Through a dual regulation strategy of organic molecule intercalation and non-metallic element doping, it synergistically improves ion diffusion kinetics, electronic conductivity, and structural stability, providing a new material and approach for high-performance aqueous zinc-ion batteries. Summary of the Invention
[0007] This invention aims to overcome the shortcomings of existing technologies and provide a simple and structurally controllable method for preparing manganese dioxide co-doped with organic amines and phosphorus. This method significantly improves the electrochemical performance of manganese dioxide through the synergistic effect of organic amine intercalation and phosphorus doping.
[0008] The present invention discloses a method for preparing manganese dioxide co-doped with organic amine and phosphorus, comprising the following steps:
[0009] (1) Prepare a potassium permanganate solution with a concentration of 0.01-0.02 mol / L and preheat it in a water bath at 60℃ for 2-3 hours; then prepare a sodium thiosulfate solution with the same concentration range and add it dropwise to the potassium permanganate solution under stirring to obtain a manganese dioxide precursor solution.
[0010] (2) Under continuous stirring, organic amine is added dropwise to the solution obtained in step (1) and reacted at 60°C for 2-3 hours; after the reaction is completed, the suspension is washed with water and filtered, the solid product is collected and dried under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0011] (3) Place sodium hypophosphite in the upstream zone of the tubular furnace and place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone; under an inert atmosphere, heat to 200-300℃ at 2-5℃ / min, hold for 1-1.5 hours, and cool with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0012] Further, the organic amine mentioned in step (2) is selected from ethylenediamine, propylenediamine or diethylenetriamine.
[0013] Furthermore, the inert atmosphere mentioned in step (3) is argon or nitrogen.
[0014] Furthermore, in step (3), the mass ratio of sodium hypophosphite to organic amine-doped manganese dioxide is 1:1 to 1:6.
[0015] This invention also relates to an organic amine / phosphorus co-doped manganese dioxide material prepared by the method described above. The material is used as the cathode material in an aqueous zinc-ion battery.
[0016] The present invention also relates to an aqueous zinc-ion battery in which the positive electrode comprises the above-described material.
[0017] This invention achieves effective control over the interlayer spacing, electronic structure, and ion transport kinetics of manganese dioxide through the synergistic effect of organic amine intercalation and phosphorus doping. The introduction of organic amines not only widens the interlayer spacing, but their amino functional groups also enhance framework stability; phosphorus doping introduces lattice defects and active sites, further optimizing electron conduction and ion diffusion performance. The composite material prepared by this method shows good application potential in energy storage devices such as supercapacitors, lithium / sodium-ion batteries, and zinc-ion batteries. Attached Figure Description
[0018] Figure 1 Scanning electron microscope (SEM) image of organic amine / phosphorus co-doped manganese dioxide prepared in Example 1 of this invention.
[0019] Figure 2 The infrared spectrum of the organic amine / phosphorus co-doped manganese dioxide prepared in Example 1 of this invention.
[0020] Figure 3 This is a SEM image of pure manganese dioxide prepared in Comparative Example 1 of this invention.
[0021] Figure 4 This is a SEM image of the organic amine-doped manganese dioxide prepared in Comparative Example 2 of this invention.
[0022] Figure 5 This is a SEM image of phosphorus-doped manganese dioxide prepared in Comparative Example 3 of this invention.
[0023] Figure 6 The X-ray lattice diffraction patterns are of the materials prepared in Examples 1, 1, 2 and 3 of this invention. Detailed Implementation
[0024] The present invention will be further illustrated by the following examples and comparative examples, but the present invention is not limited to the following contents.
[0025] Example 1
[0026] A method for preparing manganese dioxide co-doped with organic amine and phosphorus includes the following steps:
[0027] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0028] (2) Add 5 mL of ethylenediamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0029] (3) Weigh 0.3 g of sodium hypophosphite (with a mass ratio of 1:2 to organic amine-doped manganese dioxide) and place it in the upstream zone of the tube furnace. Place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone. Introduce argon gas as a protective atmosphere and raise the temperature to 200°C at a rate of 5°C / min. Hold the temperature for 1 hour and then cool it with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0030] Example 2
[0031] A method for preparing manganese dioxide co-doped with organic amine and phosphorus includes the following steps:
[0032] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0033] (2) Add 5 mL of ethylenediamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0034] (3) Weigh 0.45 g of sodium hypophosphite (with a mass ratio of 1:3 to organic amine-doped manganese dioxide) and place it in the upstream zone of the tube furnace. Place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone. Introduce argon gas as a protective atmosphere and raise the temperature to 200°C at a rate of 5°C / min. After holding at this temperature for 1 hour, cool the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0035] Example 3
[0036] A method for preparing manganese dioxide co-doped with organic amine and phosphorus includes the following steps:
[0037] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0038] (2) Add 5 mL of ethylenediamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0039] (3) Weigh 0.6 g of sodium hypophosphite (with a mass ratio of 1:4 to organic amine-doped manganese dioxide) and place it in the upstream zone of the tube furnace. Place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone. Introduce argon gas as a protective atmosphere and raise the temperature to 250°C at a rate of 5°C / min. Hold the temperature for 1 hour and then cool it with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0040] Example 4
[0041] A method for preparing manganese dioxide co-doped with organic amine and phosphorus includes the following steps:
[0042] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0043] (2) Add 5 mL of propylenediamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0044] (3) Weigh 0.3 g of sodium hypophosphite (with a mass ratio of 1:2 to organic amine-doped manganese dioxide) and place it in the upstream zone of the tube furnace. Place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone. Introduce argon gas as a protective atmosphere and raise the temperature to 280°C at a rate of 5°C / min. Hold the temperature for 1.5 hours and then cool it with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0045] Example 5
[0046] A method for preparing manganese dioxide co-doped with organic amine and phosphorus includes the following steps:
[0047] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0048] (2) Add 5 mL of diethylenetriamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0049] (3) Weigh 0.3 g of sodium hypophosphite (with a mass ratio of 1:2 to organic amine-doped manganese dioxide) and place it in the upstream zone of the tube furnace. Place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone. Introduce argon gas as a protective atmosphere and raise the temperature to 220°C at a rate of 5°C / min. Hold the temperature for 1 hour and then cool it with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
[0050] Comparative Example 1 (pure manganese dioxide)
[0051] Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60°C for 3 hours. Separately prepare 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution with continuous stirring. Continue stirring at 60°C for another 3 hours to obtain a manganese dioxide suspension. After the reaction is complete, wash the resulting suspension with water, filter, collect the solid product, and dry it under vacuum for 24 hours to obtain pure manganese dioxide.
[0052] Comparative Example 2 (Organic Amine Doped with Manganese Dioxide)
[0053] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; prepare another 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring to obtain a manganese dioxide precursor solution.
[0054] (2) Add 5 mL of ethylenediamine to the above solution and stir at 60°C for 3 hours. After the reaction is complete, wash the resulting suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain organic amine-doped manganese dioxide.
[0055] Comparative Example 3 (Phosphorus-doped manganese dioxide)
[0056] (1) Prepare 50 mL of 0.02 mol / L potassium permanganate solution and stir magnetically in a water bath at 60℃ for 3 hours; separately prepare 50 mL of 0.02 mol / L sodium thiosulfate solution and add it dropwise to the potassium permanganate solution under continuous stirring. Continue stirring and reacting at 60℃ for 3 hours to obtain a manganese dioxide suspension. After the reaction is complete, wash the obtained suspension with water, filter it, collect the solid product, and dry it under vacuum for 24 hours to obtain pure manganese dioxide.
[0057] (2) Weigh 0.3 g of sodium hypophosphite and place it in the upstream zone of the tubular furnace, and place the manganese dioxide obtained in step (1) in the downstream zone. Argon gas is introduced as a protective atmosphere, and the temperature is raised to 200°C at a rate of 5°C / min. After holding at this temperature for 1 hour, the furnace is cooled to obtain phosphorus-doped manganese dioxide.
[0058] Electrochemical performance testing
[0059] The material prepared above was used as the positive electrode active material and mixed with acetylene carbon black conductive agent and polyvinylidene fluoride binder at a mass ratio of 7:2:1. N-methyl-2-pyrrolidone was added and ground into a slurry, which was then coated onto titanium foil, dried, and cut into positive electrode sheets. A coin cell was assembled using zinc sheet as the negative electrode, glass fiber as the separator, and a 0.2 mol / L MnSO4 + 2 mol / L ZnSO4 solution as the electrolyte. Constant current charge-discharge tests were performed using a Blue Battery testing system.
[0060] Test Results
[0061] Table 1 Comparison of cycling performance (tested under a current density of 2 A / g)
[0062]
[0063] Table 2. Rate performance comparison (specific capacity read after 5 cycles at current densities of 0.1 A / g, 0.3 A / g, 0.5 A / g and 0.1 A / g respectively)
[0064]
[0065] From SEM image ( Figure 1 , Figure 3-5 As can be seen, the material obtained in Example 1 has finer particles, more uniform dispersion, and no severe stacking, which is beneficial for ion transport.
[0066] From infrared spectrum ( Figure 2 As can be seen, the bonds between amino, phosphorus and O in the material obtained in Example 1 indicate the success of the doping of organic amine and phosphorus with manganese dioxide.
[0067] From X-ray diffraction pattern ( Figure 6 As can be seen, the crystal structure of the material obtained in Example 1 is consistent with that of manganese dioxide in Comparative Example 1. Through doping, the diffraction peak of the (-111) crystal plane of manganese dioxide shifts to a smaller angle, indicating that doping expands the lattice spacing of layered manganese dioxide.
[0068] Electrochemical tests (Tables 1-2) show that the organic amine / phosphorus co-doped manganese dioxide prepared in this invention has higher specific capacity, better rate performance, and better cycle stability.
[0069] In summary, the preparation method provided by this invention is simple, mild, and environmentally friendly, and the resulting composite material has a stable structure and excellent electrochemical performance, making it suitable for high-performance energy storage devices.
[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing manganese dioxide co-doped with organic amine and phosphorus, characterized in that, Includes the following steps: (1) Prepare a potassium permanganate solution with a concentration of 0.01-0.02 mol / L and preheat it in a water bath at 60℃ for 2-3 hours; Prepare a sodium thiosulfate solution of equal concentration range and add it dropwise to a potassium permanganate solution under stirring to obtain a manganese dioxide precursor solution. (2) Under continuous stirring, organic amine is added dropwise to the solution obtained in step (1) and reacted at 60°C for 2-3 hours; after the reaction is completed, the suspension is washed with water and filtered, the solid product is collected and dried under vacuum for 24 hours to obtain organic amine-doped manganese dioxide. (3) Place sodium hypophosphite in the upstream zone of the tubular furnace and place the organic amine-doped manganese dioxide obtained in step (2) in the downstream zone; under an inert atmosphere, heat to 200-300℃ at 2-5℃ / min, hold for 1-1.5 hours, and cool with the furnace to obtain organic amine / phosphorus co-doped manganese dioxide.
2. The preparation method according to claim 1, characterized in that, The organic amine mentioned in step (2) is selected from ethylenediamine, propylenediamine or diethylenetriamine.
3. The preparation method according to claim 1, characterized in that, The inert atmosphere mentioned in step (3) is argon or nitrogen.
4. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of sodium hypophosphite to organic amine-doped manganese dioxide is 1:1 to 1:
6.
5. An organic amine / phosphorus co-doped manganese dioxide material prepared by the method according to any one of claims 1-4.
6. The material according to claim 5, characterized in that, The material is used as the positive electrode in aqueous zinc-ion batteries.
7. An aqueous zinc-ion battery, characterized in that, Its positive electrode comprises the material described in claim 5.