Calcium ion doped manganese dioxide positive electrode material, preparation method thereof and application of calcium ion doped manganese dioxide positive electrode material in aqueous magnesium ion capacitor
By using calcium ion doped manganese dioxide positive electrode material in magnesium ion batteries, the problem of slow dendrite formation and magnesium ion diffusion kinetics in magnesium ion batteries is solved, and the effects of high specific capacitance and long discharge time are achieved, which improves the safety and economy of the battery.
Patent Information
- Application Number
- CN202510171550.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-17
- Publication Date
- 2025-05-16
AI Technical Summary
In aqueous magnesium ion batteries, dendrite formation of the positive electrode material leads to poor safety, limited lithium resources, and slow diffusion kinetics of magnesium ions, resulting in low reversible specific capacity.
Calcium ion-doped manganese dioxide (Ca0.12MnO2·0.5H2O) was used as the cathode material, and the composite material was prepared by hydrothermal reaction and used in combination with activated carbon to improve the intercalation and removal efficiency of magnesium ions.
The specific capacitance of the aqueous magnesium ion capacitor is significantly improved, the discharge time is increased by about 1420 seconds, which is about 1.4 times larger than the original MnO2, and the material is highly safe and low cost.
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Figure CN120015537A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of materials, and relates to a calcium ion-doped manganese dioxide positive electrode material, a preparation method thereof, and an application in an aqueous magnesium ion capacitor. Background Art
[0002] In the field of efficient storage of electrical energy, commercial rechargeable lithium-ion batteries still dominate the current market. However, poor safety caused by dendrite formation, limited lithium resources and low power density mainly based on plug-in are huge obstacles limiting their long-term application in the future energy storage field. Therefore, it is crucial to find energy storage devices to replace lithium-ion batteries and develop clean, green and safe energy systems. Aqueous rechargeable magnesium-ion batteries are considered to be the most promising alternative due to their abundant environmentally friendly magnesium elements, high intrinsic safety and good ionic conductivity of water-based electrolytes. Compared with the standard hydrogen electrode, the negative reduction potential of the Mg anode is -2.37V, which is close to that of the lithium electrode, and the tendency of dendrite formation is low, so it can provide high energy and stable performance. Compared with lithium-ion batteries, magnesium-ion batteries also have higher material abundance (about 2.9% of the earth's crust reserves), high theoretical volume capacity (about 3833mAh / cm 3 ), higher safety and lower cost. The biggest challenge facing magnesium-ion batteries is the potential decomposition of water during charge and discharge (GCD). The thermodynamic potential of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) caused by water electrolysis will limit the working voltage between electrode materials, which is not conducive to the electrochemical reaction. For the positive electrode material, divalent Mg 2+ Ions have a strong electrostatic effect on the host, resulting in slow diffusion kinetics and low reversible specific capacity. Therefore, a reasonable insertion framework is designed to increase the interlayer distance of the material and optimize the Mg 2+ Diffusion channels are more conducive to the embedding and extraction of magnesium ions, thus improving the cycle performance. Summary of the invention
[0003] The purpose of the present invention is to use a manganese-based composite material doped with metal ions as a positive electrode material in an aqueous magnesium ion capacitor, and the provided aqueous magnesium ion capacitor has significantly improved specific capacitance.
[0004] To achieve the above object, the technical solution adopted by the present invention is:
[0005] A calcium ion-doped manganese dioxide positive electrode material, the preparation method of which comprises the following steps:
[0006] 1) Potassium permanganate, manganese sulfate monohydrate and anhydrous calcium chloride are added to deionized water in sequence, dissolved by magnetic stirring to make them evenly dispersed, and the solution is transferred to a high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction, centrifuged and washed, and dried to obtain Ca 0.12MnO 2 0.5H 2 O composite materials.
[0007] Furthermore, the above-mentioned method for preparing a calcium ion-doped manganese dioxide positive electrode material comprises: 0.12 MnO 2 0.5H 2 In the composite material, KMnO 4 :MnSO 4 ·H 2 O:CaCl 2 =6:1:2.
[0008] Furthermore, in the above-mentioned method for preparing a calcium ion-doped manganese dioxide positive electrode material, the hydrothermal reaction is carried out at 140° C. for 10 hours.
[0009] Application of a calcium ion-doped manganese dioxide positive electrode material as described in any one of the above in an aqueous magnesium ion capacitor.
[0010] Furthermore, the above application method comprises the following steps:
[0011] 1) Preparation of positive electrode: Ca 0.12 MnO 2 0.5H 2 After the O composite material is mixed evenly with the binder and the conductive material, a small amount of NMP is added as a dispersion liquid. After mixing evenly, the slurry is directly applied to the substrate carbon paper, dried in a vacuum drying oven at 60°C for 12 hours, and then taken out and punched using a punching machine to obtain a sheet coated with Ca 0.12 MnO 2 0.5H 2 O composite material positive electrode sheet;
[0012] 2) Preparation of negative electrode: After the activated carbon is mixed with the binder and the conductive material, a small amount of NMP is added as a dispersion liquid. After mixing evenly, the slurry is directly applied on the substrate carbon paper, dried in a vacuum drying oven at 60°C for 12 hours, and then taken out and punched using a punching machine to obtain a negative electrode sheet coated with activated carbon;
[0013] 3) Preparation of aqueous magnesium ion capacitors: Place the prepared negative electrode sheet coated with activated carbon into the center of the negative electrode shell, then place the diaphragm into the negative electrode shell, and drip the electrolyte to fully wet the diaphragm, then 0.12 MnO 2 0.5H 2 One side of the positive electrode sheet of the O composite material contacts the wetted diaphragm, and finally a gasket and a spring are placed therein, and after packaging, an aqueous magnesium ion capacitor is obtained.
[0014] Furthermore, in the above application, the binder is carboxymethyl cellulose or polyvinylidene fluoride.
[0015] Furthermore, in the above application, the conductive material is acetylene black or Super P.
[0016] Furthermore, in the above application, the electrolyte is MgSO 4 Solution, MgCl 2 solution and Mg(NO 3 ) 2 Any kind of solution.
[0017] Preferably, the concentration of the electrolyte is 0.5M, and the amount added is 200 μL.
[0018] Furthermore, in the above application, the diaphragm is any one of a glass fiber diaphragm, a polypropylene membrane, a filter paper diaphragm and a polymer semipermeable membrane.
[0019] The beneficial effects of the present invention are:
[0020] 1. The present invention designs a novel aqueous magnesium ion asymmetric capacitor, with Ca 0.12 MnO 2 0.5H 2 O composite materials and activated carbon as positive and negative electrode materials, respectively. It has the following advantages: First, metallic calcium is an ideal doping element for metal oxides, which is cost-effective and less toxic. More importantly, the pre-embedded divalent calcium ions can effectively strengthen the layered structure by combining with oxygen atoms to form stable Ca-O chemical bonds; second, due to the MnO 4- and Mn 2+ At a relatively low temperature of 140 °C, the reaction was insufficient and Mn vacancies were successfully introduced into MnO. 2 In the crystal lattice; Thirdly, during the first charge and discharge process, the material will form a conductive SEI film with the electrolyte, which adheres to the surface of the material, inhibits the degradation of the positive electrode material in the aqueous electrolyte, and improves its conductivity and electrochemical stability. In addition, the material contains a small amount of crystal water, which also plays a role as a support for some water molecules.
[0021] 2. The present invention adopts a calcium ion doped manganese dioxide positive electrode material to prepare an aqueous magnesium ion capacitor. After calcium doping, the discharge time is increased by about 1420 seconds, and the specific capacitance is as high as 302.06F / g, which is higher than the original MnO 2 Increased by about 1.4 times.
[0022] 3. The raw synthetic materials selected in the present invention have the characteristics of being cheap, environmentally friendly, recyclable and non-toxic. 0.12 MnO 2 0.5H2 The O composite material also has a high specific capacitance and is highly compatible with the selected electrolyte.
[0023] 4. The present invention adopts Ca 0.12 MnO 2 0.5H 2 The O composite material is a positive electrode material combined with activated carbon as a negative electrode material. The method has a simple synthesis process, a simple assembly process, is environmentally friendly, and has a low cost. It is expected to become an ideal green energy-saving energy storage device in the future. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The MnO prepared by the present invention 2 and Ca 0.12 MnO 2 0.5H 2 XRD patterns of the O composites.
[0025] Figure 2 The Ca prepared by the present invention 0.12 MnO 2 0.5H 2 SEM spectra of O composites.
[0026] Figure 3 The Ca prepared by the present invention 0.12 MnO 2 0.5H 2 Time-voltage diagram of an asymmetric aqueous magnesium ion capacitor assembled from O composite material and activated carbon.
[0027] Figure 4 The Ca prepared by the present invention 0.12 MnO 2 0.5H 2 Asymmetric aqueous magnesium ion capacitors assembled from MnO composites and activated carbon and pristine MnO 2 Comparison of specific capacitance of asymmetric aqueous magnesium ion capacitors assembled with activated carbon. DETAILED DESCRIPTION
[0028] Example 1
[0029] (I) A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0030] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 140°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum oven at 60°C for 12h to obtain the target Ca 0.12 MnO 2 0.5H 2 O material (CaMO-140).
[0031] (II) Comparative Example: The preparation method of the original manganese dioxide is as follows:
[0032] 0.1896g potassium permanganate and 0.0338g manganese sulfate monohydrate were added to 30mL deionized water, and the two were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene, and hydrothermally reacted at 140°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum drying oven at 60°C for 12h to obtain the comparative example MnO 2 Material.
[0033] (III) Detection
[0034] Figure 1 is the XRD spectrum of the calcium ion doped manganese dioxide composite material prepared in this embodiment. Figure 1 It can be seen that after the hydrothermal reaction, the obtained material is MnO 2 (PDF#80-1098) and Ca 0.12 MnO 2 0.5H 2 After Ca doping, the XRD spectrum of the sample did not show obvious changes. The shift of individual peaks indicated that Ca ions were successfully doped into MnO. 2 middle.
[0035] Figure 2 is a SEM spectrum of the calcium ion doped manganese dioxide composite material prepared in this embodiment. Figure 2 It can be seen that the pre-embedded divalent calcium ions form stable Ca-O chemical bonds by combining with oxygen atoms, forming a smaller nanoflower-like structure.
[0036] Example 2
[0037] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0038] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 110°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum drying oven at 60°C for 12h to obtain the target material CaMO-110.
[0039] Example 3
[0040] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0041] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 120°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum drying oven at 60°C for 12h to obtain the target material CaMO-120.
[0042] Example 4
[0043] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0044] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 130°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum oven at 60°C for 12h to obtain the target material CaMO-130.
[0045] Example 5
[0046] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0047] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 150°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum oven at 60°C for 12h to obtain the target material CaMO-150.
[0048] Example 6
[0049] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0050] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 160°C for 10h, and then naturally cooled to room temperature. Finally, it was washed three times with deionized water and ethanol, and dried in a vacuum oven at 60°C for 12h to obtain the target material CaMO-160.
[0051] Example 7
[0052] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0053] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 170°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum oven at 60°C for 12h to obtain the target material CaMO-170.
[0054] Example 8
[0055] A method for preparing a calcium ion-doped manganese dioxide positive electrode material is as follows:
[0056] 0.1896g potassium permanganate, 0.0338g manganese sulfate monohydrate, and 0.044g anhydrous calcium chloride were added to 30mL deionized water in sequence, and the three were fully dissolved by magnetic stirring for 1h. The solution was then transferred to a polytetrafluoroethylene-lined autoclave for hydrothermal reaction at 180°C for 10h, and then naturally cooled to room temperature. Finally, it was washed with deionized water and ethanol three times, and dried in a vacuum oven at 60°C for 12h to obtain the target material CaMO-180.
[0057] Example 9
[0058] (I) An aqueous magnesium ion capacitor with calcium ion doped manganese dioxide as a positive electrode material, the preparation method is as follows:
[0059] 1) Preparation of positive electrode: 40 mg of Ca obtained in Example 1 0.12 MnO 2 0.5H 2 After the O composite material was mixed evenly with 5 mg of polyvinylidene fluoride and 5 mg of Super P, a small amount of NMP was added as a dispersion liquid to fully grind and mix the polyvinylidene fluoride and other substances. Then, the slurry was directly applied to the substrate carbon paper, placed in a vacuum drying oven at 60°C for drying, and taken out and punched using a punching machine to obtain a film coated with Ca 0.12 MnO 2 0.5H 2 O composite material positive electrode sheet;
[0060] 2) Preparation of negative electrode: 40 mg of activated carbon was mixed with 5 mg of polyvinylidene fluoride and 5 mg of Super P, and a small amount of NMP was added as a dispersion liquid. After mixing evenly, the slurry was directly applied on the substrate carbon paper, dried in a vacuum drying oven at 60°C for 12 hours, and then taken out and punched using a punching machine to obtain a negative electrode sheet coated with activated carbon;
[0061] 3) Preparation of aqueous magnesium ion capacitors: Place the negative electrode sheet coated with activated carbon into the center of the negative electrode shell, then place the diaphragm into the negative electrode shell, and drop 200 μL 0.5 M MgSO 4 electrolyte, and then coated with Ca 0.12 MnO 2 0.5H 2 The positive electrode of the composite material was placed in contact with the wetted diaphragm, and finally the gasket and spring were placed in the CR2032 button battery using a battery packaging machine to obtain an asymmetric aqueous magnesium ion capacitor Ca 0.12 MnO 2 0.5H 2 O / / AC.
[0062] In addition, the comparative example is MnO2 As the positive electrode material, the original MnO 2 Asymmetric aqueous magnesium ion capacitors assembled with activated carbon MnO 2 / / AC.
[0063] (II) Performance test
[0064] Figure 3 This is a time-voltage diagram of an asymmetric aqueous magnesium ion capacitor assembled from a calcium ion-doped manganese dioxide composite material and activated carbon prepared by the present invention. Figure 3 It can be seen that the discharge time of the calcium ion-doped manganese dioxide composite material obtained in Example 1 is significantly longer than that of the original single manganese-based material, which is about 1420 seconds longer than that of the original manganese dioxide.
[0065] Figure 4 The specific capacitance comparison diagram of an asymmetric aqueous magnesium ion capacitor assembled with a calcium ion-doped manganese dioxide composite material and activated carbon prepared by the present invention and an asymmetric aqueous magnesium ion capacitor assembled with original manganese dioxide and activated carbon is shown in FIG. Figure 4 It can be seen that the calcium ion doped manganese dioxide composite material obtained in Example 1 has a specific capacitance of up to 302.06 F / g, which is about 1.4 times greater than that of the original manganese dioxide, compared with the original single manganese-based material.
Claims
1. A calcium ion doped manganese dioxide positive electrode material, characterized in that: The preparation method comprises the following steps: Potassium permanganate, manganese sulfate monohydrate and anhydrous calcium chloride were added to deionized water, dissolved by magnetic stirring to make them uniformly dispersed, and the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction, centrifuged and washed, and dried to obtain Ca 0.12 MnO2·0.5H2O composite materials.
2. The calcium ion-doped manganese dioxide positive electrode material according to claim 1, characterized in that: In Ca 0.12 In the MnO2·0.5H2O composite material, the molar ratio is KMnO4:MnSO4·H2O:CaCl2=6:1:
2.
3. The calcium ion-doped manganese dioxide positive electrode material according to claim 1, characterized in that: The hydrothermal reaction is carried out at 110-180° C. for 10 hours.
4. Use of the calcium ion doped manganese dioxide positive electrode material according to claim 1, 2 or 3 in an aqueous magnesium ion capacitor.
5. The use according to claim 4, characterized in that: The method comprises the following steps: 1) Preparation of positive electrode: Ca 0.12 After the MnO2·0.5H2O composite material is mixed evenly with the binder and the conductive material, a small amount of NMP is added as a dispersion liquid. After mixing evenly, the slurry is directly applied on the substrate carbon paper, dried, taken out and punched to obtain a sheet coated with Ca 0.12 Positive electrode sheet of MnO2·0.5H2O composite material; 2) Preparation of negative electrode: After the activated carbon is mixed with the binder and the conductive material, a small amount of NMP is added as a dispersion liquid. After mixing evenly, the slurry is directly applied on the substrate carbon paper, dried, taken out and punched to obtain a negative electrode sheet coated with activated carbon; 3) Preparation of aqueous magnesium ion capacitors: Place the prepared negative electrode sheet coated with activated carbon into the center of the negative electrode shell, then place the diaphragm into the negative electrode shell, and drip the electrolyte to fully wet the diaphragm, then 0.12 One side of the positive electrode sheet of the MnO2·0.5H2O composite material contacts the wetted diaphragm, and finally a gasket and a spring are placed therein, and after packaging, an aqueous magnesium ion capacitor is obtained.
6. The use according to claim 5, characterized in that: The binder is carboxymethyl cellulose or polyvinylidene fluoride.
7. The use according to claim 5, characterized in that: The conductive material is acetylene black or Super P.
8. The use according to claim 5, characterized in that: The electrolyte is any one of MgSO4 solution, MgCl2 solution and Mg(NO3)2 solution.
9. The use according to claim 8, characterized in that: The concentration of the electrolyte is 0.5 M, and the amount added is 200 μL.
10. The use according to claim 5, characterized in that: The diaphragm is any one of a glass fiber diaphragm, a polypropylene membrane, a filter paper diaphragm and a polymer semipermeable membrane.