Preparation method and application of heterostructure manganese-based positive electrode material
By preparing heterostructured α/β-MnO2 cathode materials, the shortcomings of zinc-ion battery cathode materials in terms of cycle stability and specific capacity were solved, and the performance of efficient zinc-manganese batteries was improved.
Patent Information
- Application Number
- CN202511579338.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-02-06
AI Technical Summary
The existing zinc-ion battery cathode material α-MnO2 suffers from poor cycle stability during charge-discharge cycling due to the Jahn-Teller effect, while β-MnO2 has a low initial specific capacity due to the narrow tunnel structure that hinders Zn2+ insertion.
Using potassium permanganate and manganese sulfate as raw materials, heterostructured α/β-MnO2 cathode materials were prepared through hydrothermal reaction and high-temperature annealing. The growth and crystallization process of MnOOH nanorods were regulated to form heterostructured manganese dioxide.
It improves the specific capacity and cycle stability of zinc-manganese batteries, solves the problems of few extraction channels and poor reversibility of insertion and extraction of monocrystalline manganese dioxide ions, and significantly enhances the performance of the cathode of aqueous zinc-ion batteries.
Smart Images
Figure CN121470545A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery material preparation technology, specifically to a method for preparing a heterostructure manganese-based cathode material and its application. Background Technology
[0002] With the widespread use of fossil fuels such as coal, natural gas, and oil in daily life, industrial production, and transportation, their reserves are increasingly depleted, and the accompanying environmental pollution problems are becoming increasingly severe. Therefore, developing green and sustainable new energy sources has become a crucial issue that urgently needs to be addressed. Against this backdrop, secondary batteries, due to their low cost, environmental friendliness, and excellent cycle stability, are considered one of the most promising electrochemical energy storage technologies, encompassing various systems such as lithium-ion batteries, sodium-ion batteries, aluminum-ion batteries, zinc-ion batteries, and metal-air batteries. Among them, aqueous zinc-ion batteries (AZIBs), with their high safety, low cost, and good environmental compatibility due to the metallic zinc anode and aqueous electrolyte, are considered a highly promising energy storage system. Specifically, zinc-ion batteries possess advantages such as high safety, suitable redox potential, low toxicity, and simple manufacturing processes. The cathode material, as a key component determining the electrochemical performance of AZIBs, has received widespread attention in recent years. Manganese dioxide (MnO2) is favored due to its abundant natural resources, low cost, and high theoretical specific capacity (based on MnO2). 4+ / Mn 2+ With a high reaction rate (up to 616 mAh / g) and a relatively high operating voltage plateau (approximately 1.35 V), and possessing diverse tunnel structures and layered crystal structures, it is considered one of the ideal cathode material candidates. Among them, α-MnO2, due to its 2*2 tunnel structure, is a Zn... 2+ The rapid, reversible embedding / extraction provides ample space and reduces Zn 2+ The high initial specific capacity is due to the high diffusion barrier of α-MnO2. However, during charge-discharge cycling, the Jahn-Teller effect inevitably occurs, leading to poor cycle stability and rapid capacity decay in α-MnO2. β-MnO2, due to its dense 1*1 tunnel structure, can effectively suppress lattice distortion and phase transitions during charge-discharge, exhibiting excellent long cycle life. However, the narrow 1*1 tunnels severely hinder the diffusion of Zn. 2+ The electrochemical process relies more on surface control than bulk intercalation, resulting in typically low initial specific capacity. Therefore, optimizing the MnO2 structure while simultaneously improving capacity and stability has become a key research focus.
[0003] Therefore, in order to solve the above problems, this paper proposes a method for preparing heterostructure manganese-based cathode materials and their applications. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing a heterostructured manganese-based cathode material; using potassium permanganate and manganese sulfate as raw materials, a precursor MnOOH is obtained through high-temperature hydrothermal treatment, and then the heterostructured manganese-based cathode material (α / β-MnO2 cathode material) is obtained through high-temperature annealing.
[0005] To achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: a method for preparing a heterostructure manganese-based cathode material, characterized by comprising the following steps:
[0006] S1. Weigh out potassium permanganate and manganese sulfate monohydrate in a molar ratio of potassium permanganate: manganese sulfate monohydrate = 2.2~2.5:1; then dissolve potassium permanganate and manganese sulfate monohydrate in deionized water, and stir magnetically for 30~50 minutes at room temperature until completely dissolved to obtain mixed solution A;
[0007] S2. Transfer the mixed solution A obtained in S1 to a hydrothermal reactor, and then heat the hydrothermal reactor in a forced-air drying oven at a reaction temperature of 150-180℃ for 10-12 hours for hydrothermal reaction. After the reaction is complete, MnOOH is formed.
[0008] S3. After cooling the product obtained in S2 to room temperature, wash it by centrifuging with deionized water and ethanol at 6000-8000 r / min for 5-8 min, and repeat the process 3-5 times.
[0009] S4. The product obtained in S3 is dried in a forced-air drying oven at a drying temperature of 50-80℃ for 10-15 hours, and then naturally cooled to 30℃. The material is then taken out and ground to obtain the precursor MnOOH material.
[0010] S5. Anneal the precursor MnOOH obtained in S4 in a tube furnace at 400-700℃ for 2-5 hours, then allow it to cool naturally to 30℃, remove the material and grind it; the heterostructure manganese-based cathode material can then be obtained.
[0011] Another objective of this invention is to provide a method for preparing a cathode sheet from a heterostructure manganese-based cathode material, characterized by comprising the following steps:
[0012] S1. Take the heterostructured manganese-based cathode material, conductive carbon black and PVDF solution in a mass ratio of 7:2:1.
[0013] S2. The heterostructured manganese-based cathode material, conductive carbon black and PVDF solution weighed above are mechanically mixed to obtain a slurry;
[0014] S3. Coat the slurry obtained in S2 onto a stainless steel mesh, and dry it at 50-80℃ for 6-12 hours before removing it.
[0015] S4. Cut the removed stainless steel mesh into circular pieces with a diameter of 10-14 mm to obtain the positive electrode sheet (α / β-MnO2 positive electrode sheet) prepared from the heterostructure manganese-based positive electrode material.
[0016] Furthermore, the mass concentration of the PVDF is 1-4%.
[0017] Furthermore, the mass concentration of the PVDF is 2%.
[0018] Another objective of this invention is to provide an application of a heterostructured manganese-based cathode material in new energy batteries.
[0019] Furthermore, the specific applications of the heterostructured manganese-based cathode material in new energy batteries are as follows:
[0020] ① A button cell is assembled using the prepared α / β-MnO2 positive electrode as the positive electrode, a zinc metal sheet as the negative electrode, and a glass fiber separator.
[0021] ② Using the prepared α / β-MnO2 positive electrode as the positive electrode, a zinc metal sheet as the negative electrode, and an aqueous solution of zinc salt and manganese salt as the electrolyte, an aqueous zinc-ion battery is assembled.
[0022] Furthermore, the solvent of the battery electrolyte used in step ② is deionized water, containing 2M ZnSO4 + 0.2M MnSO4 as solute.
[0023] Furthermore, to determine the battery performance, the assembled button cells were left to stand for 2–6 hours, and the assembled button cells were tested at a current density of 0.5 Ag. -1 and 1Ag -1 Under these conditions, long-cycle tests were conducted, and charge-discharge tests and rate cycling performance tests were performed at different current densities.
[0024] The beneficial effects of this invention are:
[0025] (1) This invention regulates the growth and crystallization process of MnOOH nanorods under thermodynamic equilibrium conditions, and then places the MnOOH nanorods in a muffle furnace for heat treatment to obtain α / β-MnO2 cathode material; without changing the morphology, a heterostructured manganese dioxide cathode material is prepared, which improves the specific capacity and cycle stability of zinc-manganese batteries.
[0026] (2) The manganese dioxide prepared by this method is a heterostructure manganese dioxide, which is different from the traditional single crystal manganese dioxide. This sample has more and more stable tunnel structures and smaller nanoneedle structures. The application of this material in batteries solves the problems of low specific capacity and poor cycle stability caused by the small number of single crystal manganese dioxide ion precursor extraction channels and poor insertion and extraction reversibility.
[0027] (3) The preparation method of the manganese dioxide cathode material of the present invention is novel, simple to operate, low in investment cost, and can significantly improve the performance of the cathode of aqueous zinc-ion battery, and has broad application prospects. Attached Figure Description
[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is an X-ray diffraction pattern of the MnOOH precursor prepared in Example 1 of this invention;
[0030] Figure 2 This is a comparison diagram of X-ray diffraction tests of the α / β-MnO2 cathode material prepared in Example 1 of the present invention with the standard PDF cards of α-MnO2 and β-MnO2;
[0031] Figure 3 This is a scanning electron microscope image of the α / β-MnO2 cathode material prepared in Example 1 of this invention;
[0032] Figure 4 This is a transmission electron microscope image of the α / β-MnO2 cathode material prepared in Example 1 of this invention;
[0033] Figure 5 This is a comparison chart of the cycle performance of a zinc-manganese battery composed of α / β-MnO2 cathode material prepared in Example 1 of the present invention and a zinc-manganese battery composed of ordinary α-MnO2 and β-MnO2 cathode materials at a current density of 0.5Ag-1.
[0034] Figure 6 This is a comparison chart of the cycle performance of a zinc-manganese battery composed of α / β-MnO2 cathode material prepared in Example 1 of the present invention and a zinc-manganese battery composed of ordinary α-MnO2 and β-MnO2 cathode materials at a current density of 1Ag-1.
[0035] Figure 7This is a comparison chart of the rate cycling performance of a zinc-manganese battery composed of α / β-MnO2 cathode material prepared in Example 1 of this invention and a zinc-manganese battery composed of ordinary α-MnO2 and β-MnO2 cathode materials at different current densities. Detailed Implementation
[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0037] Example 1
[0038] The preparation of a heterostructured manganese-based cathode material (α / β-MnO2 cathode material) includes the following steps:
[0039] Step 1: Accurately weigh 0.988g of potassium permanganate (KMnO4) and dissolve it in 80ml of deionized water. Accurately weigh 0.479g of manganese sulfate monohydrate (MnSO4·H2O) and dissolve it in the above solution. Stir magnetically for 30min to obtain a mixed solution.
[0040] Step 2: Transfer the mixed solution obtained in Step 1 to a hydrothermal reactor and keep it in an oven at 160℃ for 12 hours.
[0041] Step 3: After cooling the product obtained in Step 2 to room temperature, wash it with deionized water and ethanol respectively and centrifuge it. The centrifugation process is to centrifuge at 6500 r / min for 5 min, and repeat the process 4 times.
[0042] Step 4: Place the product obtained in Step 3 into an oven and dry at 60℃ for 12 hours. Then, allow it to cool naturally to 30℃, remove the material, and grind it to obtain the precursor MnOOH.
[0043] Step 5: Anneal the precursor MnOOH obtained in Step 4 in a muffle furnace at 500℃ for 3 hours, then allow it to cool naturally to 30℃. Remove the material and grind it to obtain the α / β-MnO2 cathode material.
[0044] The α / β-MnO2 cathode material prepared in Example 1 was characterized as follows:
[0045] pass Figure 2 It can be seen that the α / β-MnO2 cathode material prepared in Example 1 has the same crystal form as the standard α-MnO2 and β-MnO2, that is, it is a mixed-phase manganese dioxide cathode material.
[0046] pass Figure 3 It can be seen that the α / β-MnO2 cathode material prepared in Example 1 has a nanoneedle-like morphology.
[0047] pass Figure 4 It can be seen that the α / β-MnO2 cathode material prepared in Example 1 has obvious lattice distortion at the interface between the α-MnO2 and β-MnO2 phases, that is, the heterostructure manganese-based cathode material (α / β-MnO2 cathode material) was successfully prepared.
[0048] II. Preparation of α / β-MnO2 cathode:
[0049] The α / β-MnO2 cathode material prepared above is mechanically mixed with acetylene black and a 2% PVDF solution at a mass ratio of 7:2:1 to obtain a viscous slurry. This slurry is then coated onto a stainless steel mesh and cut into 12mm round pieces to obtain the α / β-MnO2 cathode sheet. This electrode sheet is used as the cathode sheet for a coin cell.
[0050] III. Preparation of Zinc-Manganese Batteries
[0051] The aforementioned α / β-MnO2 positive electrode was assembled with a conventional zinc negative electrode and a glass fiber separator to form an LIR2032 type button cell. The electrolyte was 2M ZnSO4 + 0.2M MnSO4. The assembled cells were then left to stand for 4 hours. Similarly, cells assembled with conventional α-MnO2 and β-MnO2 positive electrodes, conventional zinc negative electrodes, and glass fiber separators were used as controls.
[0052] IV. Electrochemical Performance Testing of Zinc-Manganese Batteries
[0053] The zinc-manganese battery was subjected to cycle performance and rate performance tests on the Xinwei charge / discharge test channel. The cycle test condition was 0.5Ag. -1 and 1Ag -1 0.5Ag -1 The initial specific capacity at current density is as high as 326.23 mAh g. -1 After 200 cycles, it still has 311.87 mAh g. -1 High specific capacity. 1Ag -1 The initial specific capacity at the current density is 224.48 mAh g. -1 It retains 77% of its capacity after 1000 cycles.
[0054] Example 2
[0055] The preparation of α-MnO2 cathode material includes the following steps:
[0056] Step 1: Accurately weigh 1.264g of potassium permanganate (K2MnO4) and dissolve it in 80ml of deionized water. Accurately weigh 1.812g of manganese sulfate monohydrate (MnSO4·H2O) and dissolve it in the above solution. Stir magnetically for 60min to obtain a mixed solution.
[0057] Step 2: Transfer the mixed solution obtained in Step 1 to a hydrothermal reactor and keep it at 160℃ for 12 hours.
[0058] Step 3: After cooling the product obtained in Step 2 to room temperature, wash it with deionized water and ethanol respectively and centrifuge it. The centrifugation process is to centrifuge at 6500 r / min for 5 min, and repeat the process 5 times.
[0059] Step 4: Place the product obtained in Step 3 into an oven and dry it at 60℃ for 12 hours. Then, allow it to cool naturally to 30℃, remove the material, and grind it to obtain the α-MnO2 cathode material.
[0060] II. Preparation of α-MnO2 cathode sheet:
[0061] The prepared α-MnO2 cathode material was mechanically mixed with acetylene black and a 2% PVDF solution at a mass ratio of 7:2:1 to obtain a viscous slurry. This slurry was then coated onto a stainless steel mesh and cut into 12mm round pieces to serve as the cathode material for a coin cell.
[0062] III. Preparation of Zinc-Manganese Batteries
[0063] The above-mentioned α-MnO2 positive electrode sheet was assembled with a common zinc negative electrode sheet and a glass fiber separator to form an LIR2032 type button cell. The electrolyte was 2M ZnSO4 + 0.2M MnSO4. The assembled cell was left to stand for 8 hours.
[0064] IV. Electrochemical Performance Testing of Zinc-Manganese Batteries
[0065] The zinc-manganese battery was subjected to cycle performance and rate performance tests on the Xinwei charge / discharge test channel. The cycle test condition was 0.5Ag. -1 and 1Ag -1 0.5Ag -1 The initial specific capacity at the current density is 241.09 mAh g. -1 After 200 cycles, the specific capacity is 228.90 mAh g. -1 1Ag -1 The initial specific capacity at the current density is 224.48 mAh g. -1 After 1000 cycles, the specific capacity is only 37.19 mAh g. -1 The capacity retention rate was only 16.57%.
[0066] Example 3
[0067] The preparation of β-MnO2 cathode material includes the following steps:
[0068] Step 1: Accurately weigh 0.676 g of manganese sulfate monohydrate (MnSO4·H2O) and dissolve it in 80 ml of deionized water. Accurately weigh 0.912 g of ammonium persulfate ((NH4)2S2O8) and dissolve it in the above solution. Stir magnetically for 60 min to obtain a mixed solution.
[0069] Step 2: Transfer the mixed solution obtained in Step 1 to a hydrothermal reactor and keep it at 140℃ for 12 hours.
[0070] Step 3: After cooling the product obtained in Step 2 to room temperature, wash it with deionized water and ethanol respectively and centrifuge it. The centrifugation process is to centrifuge at 6500 r / min for 5 min, and repeat the process 5 times.
[0071] Step 4: Place the product obtained in Step 3 into an oven and dry it at 60℃ for 12 hours. Then, allow it to cool naturally to 30℃, remove the material, and grind it to obtain the β-MnO2 cathode material.
[0072] II. Preparation of β-MnO2 cathode:
[0073] The prepared β-MnO2 cathode material was mechanically mixed with acetylene black and a 2% PVDF solution at a mass ratio of 7:2:1 to obtain a viscous slurry. This slurry was then coated onto a stainless steel mesh and cut into 12mm round pieces to serve as the cathode material for coin cells.
[0074] III. Preparation of Zinc-Manganese Batteries
[0075] The above-mentioned β-MnO2 positive electrode sheet was assembled with a common zinc negative electrode sheet and a glass fiber separator to form an LIR2032 type button cell. The electrolyte was 2M ZnSO4 + 0.2M MnSO4. The assembled cell was left to stand for 8 hours.
[0076] IV. Electrochemical Performance Testing of Zinc-Manganese Batteries
[0077] The zinc-manganese battery was subjected to cycle performance and rate performance tests on the Xinwei charge / discharge test channel. The cycle test condition was 0.5Ag. -1 and 1Ag -1 0.5Ag -1 The initial specific capacity at the current density is 191.68 mAh g. -1 After 200 cycles, the specific capacity is 191.02 mAh g. -1 1Ag -1 The initial specific capacity at the current density is 137.49 mAh g. -1After 1000 cycles, the capacity is 82.44 mAh g. -1 The capacity retention rate is 60%.
[0078] Depend on Figure 5 and Figure 6 Comparison data of cycle performance, and Figure 7 The rate performance comparison data shows that the zinc-manganese battery assembled using the α / β-MnO2 prepared by the method of the present invention has higher discharge specific capacity, better cycle performance and better rate performance, indicating that the α / β-MnO2 method and the obtained positive electrode active material provided by the present invention are feasible.
[0079] The manganese dioxide prepared by this method is a heterostructured manganese dioxide, which differs from traditional single-crystal manganese dioxide. This sample possesses more and more stable tunnel structures, as well as smaller nanoneedle structures. The application of this material in batteries solves the problems of low specific capacity and poor cycle stability caused by the limited number of ion precursor extraction channels and poor intercalation / extraction reversibility in single-crystal manganese dioxide.
[0080] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A method for preparing a heterostructured manganese-based cathode material, characterized in that, Includes the following steps: S1. Weigh out potassium permanganate and manganese sulfate monohydrate in a molar ratio of potassium permanganate: manganese sulfate monohydrate = 2.2~2.5:1; then dissolve potassium permanganate and manganese sulfate monohydrate in deionized water, and stir magnetically for 30~50 minutes at room temperature until completely dissolved to obtain mixed solution A; S2. Transfer the mixed solution A obtained in S1 to a hydrothermal reactor, and then heat the hydrothermal reactor in a forced-air drying oven at a reaction temperature of 150-180℃ for 10-12 hours for hydrothermal reaction. After the reaction is complete, MnOOH is formed. S3. After cooling the product obtained in S2 to room temperature, wash it by centrifuging with deionized water and ethanol at 6000-8000 r / min for 5-8 min, and repeat the process 3-5 times. S4. The product obtained in S3 is dried in a forced-air drying oven at a drying temperature of 50-80℃ for 10-15 hours, and then naturally cooled to 30℃. The material is then taken out and ground to obtain the precursor MnOOH material. S5. Anneal the precursor MnOOH obtained in S4 in a tube furnace at 400-700℃ for 2-5 hours, then allow it to cool naturally to 30℃, remove the material and grind it; the heterostructure manganese-based cathode material can then be obtained.
2. The preparation method of the positive electrode sheet prepared from the heterostructure manganese-based positive electrode material according to claim 1, characterized in that, Includes the following steps: S1. Take the heterostructured manganese-based cathode material, conductive carbon black and PVDF solution in a mass ratio of 7:2:
1. S2. The heterostructured manganese-based cathode material, conductive carbon black and PVDF solution weighed above are mechanically mixed to obtain a slurry; S3. Coat the slurry obtained in S2 onto a stainless steel mesh, and dry it at 50-80℃ for 6-12 hours before removing it. S4. Cut the removed stainless steel mesh into circular pieces with a diameter of 10-14 mm to obtain the positive electrode sheet prepared from the heterostructure manganese-based positive electrode material.
3. The preparation method of the positive electrode sheet prepared from the heterostructure manganese-based positive electrode material according to claim 2, characterized in that, The mass concentration of the PVDF is 1-4%.
4. The preparation method of the positive electrode sheet prepared from the heterostructure manganese-based positive electrode material according to claim 3, characterized in that, The mass concentration of the PVDF is 2%.
5. The application of the heterostructure manganese-based cathode material according to claim 1 in new energy batteries.