Nitrogen-doped manganous-manganic oxide material as well as preparation method and application thereof
The formation of nitrogen-doped trimanganese tetraoxide material on the conductive substrate by electrochemical co-deposition and heat treatment methods solves the problems of complex preparation process and high cost, improves the conductivity and ion transportability of the material, and achieves higher charge and discharge performance and cycle life.
Patent Information
- Application Number
- CN202510700308.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-07-18
AI Technical Summary
The existing nitrogen-doped manganese tetraoxide preparation method has complex processes, high cost and poor control, which limits its application performance under high magnification and long cycle life conditions.
By using electrochemical co-deposition combined with heat treatment, nitrogen elements are introduced to form a nitrogen-doped manganese tetraoxide material by forming a polyphenolone composite manganese dioxide deposited film on a conductive substrate and calcining it in an oxygen-free environment.
The preparation process is simplified, the cost is reduced, and the high conductivity and ion transportability of trimanganese tetraoxide materials are achieved, which improves the charge and discharge performance, specific capacity and cycle life.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of preparation of cathode materials for secondary batteries, and particularly relates to a nitrogen-doped manganese tetroxide material, a preparation method and an application thereof. Background Art
[0002] With the rapid development of renewable energy and portable electronic devices, the demand for high-performance, low-cost and environmentally friendly energy storage devices is increasing day by day. Aqueous zinc-ion batteries have become a hot spot for the next-generation energy storage system due to their advantages such as high safety, rich raw materials, low cost and environmental friendliness. Among them, the cathode active material plays a decisive role in the battery performance.
[0003] As a cathode active material, manganese tetroxide is a typical manganese-based oxide, which has rich oxidation states, a high theoretical specific capacity and good environmental compatibility, and has been widely used in aqueous zinc-ion batteries. However, manganese tetroxide has defects such as poor conductivity and slow ion diffusion rate, which limit its application performance under high rate and long cycle life conditions.
[0004] To improve the above problems, technicians have regulated the structure and performance of manganese tetroxide by means of doping, nanosizing, carbon composite, etc. Among them, doping with non-metallic elements, especially nitrogen doping, has become a feasible optimization means because it can effectively adjust the electronic structure of manganese tetroxide, improve the conductivity and the number of active sites. However, the existing preparation methods of nitrogen-doped manganese tetroxide have problems such as complex process, high cost and poor controllability, and cannot be popularized and applied on a large scale. Summary of the Invention
[0005] Aiming at the problems existing in the prior art, the present invention provides a nitrogen-doped manganese tetroxide material, a preparation method and an application thereof, so as to solve the problems of complex process, high cost and poor controllability of nitrogen-doped manganese tetroxide. It is simple, highly controllable, suitable for large-scale preparation, improves the conductivity and ion transportability of manganese tetroxide, and realizes higher charge and discharge performance, specific capacity and longer cycle life of manganese tetroxide.
[0006] The present invention is realized by the following technical solutions:
[0007] A preparation method of a nitrogen-doped manganese tetroxide material, comprising the following steps:
[0008] Step 1, dissolve a manganese salt and phenanthroline in deionized water according to a molar ratio of (10-50):(5-10) to form a precursor solution;
[0009] Step 2, adopt an electrochemical co-deposition method to co-deposit a poly(phenanthroline) composite manganese dioxide deposition film on a conductive substrate in the precursor solution with the conductive substrate as the working electrode to form a composite electrode;
[0010] Step 3: Calcinate the composite electrode in an oxygen-free environment at 400 - 600 °C to obtain a nitrogen-doped manganese tetroxide material.
[0011] A further improvement of the present invention lies in:
[0012] In Step 1, the manganese salt is one or a mixture of manganese sulfate, manganese nitrate, or manganese acetate, and the phenanthroline is 1,10-phenanthroline or a derivative of 1,10-phenanthroline.
[0013] In Step 2, the conductive substrate is carbon cloth, carbon paper, metal foam, or conductive glass.
[0014] In Step 2, the electrochemical co-deposition is carried out by a constant current or constant potential method, with a current density of 0.5 - 1 mA / cm 2 , a potential of 1.5 - 1.8 V, and a deposition time of 10 - 60 min.
[0015] In Step 3, after drying the composite electrode at 55 - 65 °C for 10 - 12 h, then calcinate it in an oxygen-free environment at 400 - 600 °C.
[0016] The calcination treatment starts from room temperature and is carried out under the condition that the nitrogen gas flow rate is 100 - 300 SCCM, and the heating rate is 2 - 10 °C / min.
[0017] The calcination treatment is carried out for 1 - 3 h.
[0018] A nitrogen-doped manganese tetroxide material is prepared by the preparation method of the nitrogen-doped manganese tetroxide material described in any one of the above.
[0019] Application of a nitrogen-doped manganese tetroxide material in an electrochemical energy storage device.
[0020] Compared with the prior art, the present invention has the following beneficial technical effects:
[0021] In the preparation method of a nitrogen-doped manganese tetroxide material of the present invention, during the electrochemical co-deposition, Mn in the manganese salt 2+ is oxidized to Mn 3+, it is hydrolyzed to form MnOOH, which is further oxidized to MnO2 and deposited on the surface of the conductive substrate. At the same time, phenanthroline is protonated to form cations, which are prone to undergo electro-oxidation reactions to generate free radicals. The free radicals undergo dimerization or grafting reactions on the surface of the conductive substrate to form a poly(phenanthroline) film. The two processes proceed synergistically to form a poly(phenanthroline) composite manganese dioxide deposition film with a uniform structure and tight binding on the surface of the conductive substrate. When calcined in an oxygen-free environment at 400-600 °C, the poly(phenanthroline) decomposes at high temperature as a nitrogen source, releasing nitrogen-containing gases. These gases react with the surrounding MnO2 in the high-temperature environment. On the one hand, it promotes the deoxidation of MnO2 and its phase transformation into Mn3O4. On the other hand, some nitrogen atoms are doped into the lattice of Mn3O4, thus realizing the introduction of nitrogen elements. The present invention introduces nitrogen elements into the crystal structure of manganese tetraoxide through an electrochemical co-deposition combined with heat treatment method. The process is simple, low-cost, the raw materials are easily available, and the process is easy to control, suitable for large-scale preparation; by adjusting the electronic structure of manganese tetraoxide with nitrogen elements, introducing oxygen vacancies and lattice defects, the conductivity, ion transport property and electrochemical activity of the manganese tetraoxide material are significantly improved. Through charge-discharge tests, it can be known that the nitrogen-doped manganese tetraoxide material exhibits higher reversible specific capacity, better rate performance and longer cycle life.
[0022] When the nitrogen-doped manganese tetraoxide material of the present invention is applied in electrochemical energy storage devices such as aqueous zinc-ion batteries, lithium-ion batteries, sodium-ion batteries and supercapacitors, it can effectively reduce the internal resistance, relieve volume expansion, improve the energy density and cycle stability, and has broad application prospects. Brief Description of the Drawings
[0023] Figure 1 It is the X-ray diffraction (XRD) pattern of the nitrogen-doped manganese tetraoxide prepared in Example 1 of the present invention.
[0024] Figure 2 It is the X-ray photoelectron spectroscopy (XPS) pattern of the nitrogen-doped manganese tetraoxide prepared in Example 1 of the present invention.
[0025] Figure 3 It is the charge-discharge curve of the nitrogen-doped manganese tetraoxide prepared in Example 1 of the present invention in a zinc-ion battery. Detailed Description of the Invention
[0026] To more clearly illustrate the present invention, it is further described through implementation cases. The following examples do not limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
[0027] Heteroatom doping is an effective means to improve the electrochemical performance of transition metal oxide materials. As a common heteroatom, nitrogen has an electronegativity and atomic radius close to those of oxygen, and can form stable M–N bonds (M is a transition metal) in the material, thus enhancing the electron conduction path and increasing the carrier concentration. At the same time, nitrogen doping can induce lattice defects and oxygen vacancies, which is beneficial to increasing the number of electrochemically active sites in the material, enhancing the ion diffusion ability and structural stability. Therefore, nitrogen doping helps to improve the comprehensive performance of manganese tetroxide materials in aqueous energy storage devices such as zinc ion batteries.
[0028] A preparation method of a nitrogen-doped manganese tetroxide material of the present invention comprises the following steps:
[0029] Step 1: Dissolve 10 - 50 mmol of manganese salt and 5 - 10 mmol of phenanthroline (Phen) in 50 - 100 mL of deionized water to form a uniform precursor solution;
[0030] Specifically, the manganese salt is one or more of manganese sulfate, manganese nitrate or manganese acetate, and the phenanthroline is 1,10-phenanthroline or its derivative.
[0031] Step 2: Adopt the electrochemical co-deposition method. In the precursor solution, use a conductive substrate as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode, and simultaneously carry out the electrodeposition of MnO2 and the electropolymerization of phenanthroline. At the anodic potential, Mn in the solution 2+ is oxidized to Mn 3+ , hydrolyzed to form MnOOH, and further oxidized to MnO2 and deposited on the electrode surface. At the same time, Phen is protonated to form a cation in an acidic environment, which is prone to undergo an electro-oxidation reaction to generate free radicals. The free radicals undergo dimerization or grafting reactions on the electrode surface to form a poly-phenanthroline film. The two proceed synergistically to form a poly-phenanthroline composite manganese dioxide deposition film with a uniform and tightly bound structure on the surface of the conductive substrate, forming a composite electrode.
[0032] Specifically, the electrochemical co-deposition is carried out in a constant current or constant potential mode, with a current density of 0.5 - 1 mA / cm 2 , or a potential of 1.5 - 1.8 V, and a deposition time of 10 - 60 min. The conductive substrate can be carbon cloth, carbon paper, metal foam or conductive glass, and the metal foam can further be nickel foam.
[0033] Step 3: The composite electrode is dried in a vacuum drying oven at 60 °C for 10 - 12 hours, and then placed in a tube furnace for calcination treatment in a nitrogen atmosphere at 400 - 600 °C. During this process, poly(phenanthroline) decomposes at high temperature as a nitrogen source, releasing nitrogen-containing gases. These gases react with the surrounding MnO₂ in the local high-temperature environment. On the one hand, it promotes the deoxidation of MnO₂ and its phase transformation into Mn₃O₄. On the other hand, some nitrogen atoms are doped into the lattice of Mn₃O₄, thus realizing the introduction of nitrogen element. And the conductive substrate does not change in composition in a nitrogen atmosphere at 400 - 600 °C. After heat preservation, it is naturally cooled to room temperature to obtain the nitrogen-doped manganese tetroxide material.
[0034] Specifically, the calcination treatment is carried out under the condition that the nitrogen flow rate is 100 - 300 SCCM. Starting from room temperature, the calcination heating rate is 2 - 10 °C / min, and the constant temperature time is 1 - 3 h.
[0035] When the above nitrogen-doped manganese tetroxide material is applied in an electrochemical energy storage device, it can be specifically applied in an aqueous zinc-ion battery, or in a lithium-ion battery, a sodium-ion battery or a supercapacitor, and is specifically used as a positive electrode active material.
[0036] Example 1
[0037] A preparation method of a nitrogen-doped manganese tetroxide material of the present invention includes the following steps:
[0038] Step 1: Dissolve 20 mmol of manganese nitrate and 5 mmol of 1,10-phenanthroline in 100 mL of deionized water to form a uniform precursor solution.
[0039] Step 2: Use the cleaned carbon cloth (2 cm × 3 cm) as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode. Using the constant current electrodeposition method, deposit for 30 minutes under the condition of a current density of 1 mA / cm 2 to obtain a poly(phenanthroline) composite manganese dioxide deposition film.
[0040] Step 3: Dry the above-deposited composite electrode in a vacuum drying oven at 60 °C for 12 hours. Then place it in a tube furnace, heat from room temperature to 550 °C at a heating rate of 5 °C / min in a nitrogen atmosphere (flow rate 200 sccm), keep the temperature for 2 hours, and then naturally cool to room temperature to obtain the nitrogen-doped manganese tetroxide electrode material.
[0041] Example 2
[0042] A preparation method of a nitrogen-doped manganese tetroxide material of the present invention includes the following steps:
[0043] Step 1: Dissolve 25 mmol of manganese nitrate and 10 mmol of 1,10-phenanthroline in 100 mL of deionized water to form a homogeneous and transparent precursor solution.
[0044] Step 2: Take a pre-ultrasonically cleaned and dried carbon cloth (2 cm × 3 cm) as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode. Adopt the potentiostatic electrodeposition method to deposit for 20 minutes at a potential of 1.5 V to form a poly(phenanthroline) composite manganese dioxide deposition film.
[0045] Step 3: After the electrode deposition is completed, dry it in a vacuum drying oven at 60 °C for 12 hours. Place the dried sample in a tubular furnace and start from room temperature under a nitrogen atmosphere (flow rate 200 sccm), heat it to 600 °C at a rate of 5 °C / min, hold for 1.5 hours, and then naturally cool to room temperature to obtain a nitrogen-doped manganese tetroxide electrode material.
[0046] Example 3
[0047] A preparation method of a nitrogen-doped manganese tetroxide material according to the present invention includes the following steps:
[0048] Step 1: Add 15 mmol of manganese nitrate and 5 mmol of 1,10-phenanthroline to 100 mL of deionized water and magnetically stir for 30 minutes to form a homogeneous precursor solution.
[0049] Step 2: Select a (2 cm × 3 cm) carbon cloth as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode, and perform electrodeposition for 45 minutes under the condition of a constant current density of 0.5 mA / cm 2 The deposited film is dark brown.
[0050] Step 3: After the obtained electrode is dried in a vacuum drying oven at 60 °C for 12 hours, place it in a tubular furnace. Under a nitrogen atmosphere (flow rate 200 sccm), start from room temperature and heat it to 500 °C at a heating rate of 10 °C / min, hold for 3 hours, and then naturally cool to room temperature to obtain a nitrogen-doped manganese tetroxide electrode material.
[0051] Example 4
[0052] Step 1: Dissolve 30 mmol of manganese nitrate and 8 mmol of 1,10-phenanthroline in 100 mL of deionized water and ultrasonically treat for 15 minutes to obtain a clear precursor solution.
[0053] Step 2: Use a (2 cm × 3 cm) carbon cloth electrode, in combination with a platinum wire counter electrode and an Ag / AgCl reference electrode, and perform electrodeposition for 15 minutes under the condition of a potential of 1.8 V to form a poly(phenanthroline) composite manganese dioxide deposition film.
[0054] Step 3: After the electrode deposition is completed, it is dried in a vacuum drying oven at 60 °C for 10 hours, and then heated from room temperature to 550 °C at a rate of 5 °C / min under a nitrogen atmosphere (flow rate: 300 sccm), held for 2 hours, and then naturally cooled to room temperature to obtain a nitrogen-doped manganese tetroxide electrode material.
[0055] Figure 1 Figure 4 is the X-ray diffraction (XRD) pattern of the nitrogen-doped manganese tetroxide prepared in Example 1. The positions of its diffraction peaks correspond to the (103) and (211) crystal planes of manganese tetroxide (JCPDS: 97-007-6088). Therefore, it can be seen that the nitrogen-doped manganese tetroxide was successfully prepared in Example 1 of the present invention.
[0056] Figure 2 Figure 5 is the X-ray photoelectron spectroscopy (XPS) pattern of the nitrogen-doped manganese tetroxide prepared in Example 1. The presence of the N element (N1s peak) in the spectrum indicates the successful doping of the nitrogen element.
[0057] In the present invention, the nitrogen-doped manganese tetroxide obtained in Example 1 is used as the positive electrode, a zinc foil is used as the negative electrode, and a water-based zinc-ion battery is further assembled by combining an electrolyte and a CR2032 button battery. The electrolyte is a mixed solution of ZnSO4 and MnSO4, where the concentration of ZnSO4 is 2 mol / L and the concentration of MnSO4 is 0.2 mol / L. Charge-discharge experiments were carried out using this water-based zinc-ion battery, and the Figure 3 obtained charge-discharge curve diagram is shown.
[0058] As can be seen from Figure 3 Figure 6, at a charge-discharge rate of 0.2 Ag -1 -1, the discharge capacity of this water-based zinc-ion battery is 290.3 mAh g -1 -1. Therefore, it shows that the nitrogen-doped manganese tetroxide obtained in Example 1 of the present invention has a high specific capacity.
Claims
1. A preparation method of a nitrogen-doped manganese tetroxide material, characterized in that, It includes the following steps: Step 1: Dissolve manganese salt and phenanthroline in deionized water at a molar ratio of (10 - 50):(5 - 10). The manganese ion in the manganese salt is divalent to form a precursor solution. Step 2: By means of electrochemical co - deposition, use the conductive substrate as the working electrode in the precursor solution to co - deposit a poly - phenanthroline composite manganese dioxide deposition film on the conductive substrate to form a composite electrode. Step 3: Calcinate the composite electrode in an anaerobic environment at 400 - 600 °C to obtain a nitrogen - doped manganese tetraoxide material.
2. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, characterized in that, In Step 1, the manganese salt is one or a mixture of manganese sulfate, manganese nitrate, or manganese acetate.
3. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, wherein, In Step 1, the phenanthroline is 1,10 - phenanthroline or a derivative of 1,10 - phenanthroline.
4. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, wherein In Step 2, the conductive substrate is carbon cloth, carbon paper, metal foam, or conductive glass.
5. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, wherein, In Step 2, the electrochemical co-deposition is carried out in a constant current or constant potential mode, with a current density of 0.5 - 1 mA / cm 2 , a potential of 1.5 - 1.8 V, and a deposition time of 10 - 60 min.
6. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, wherein In Step 3, after drying the composite electrode at 55 - 65 °C for 10 - 12 h, then calcinate it in an anaerobic environment at 400 - 600 °C.
7. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 6, characterized in that, In the step, the calcination treatment starts from room temperature and is carried out under the condition that the nitrogen gas flow rate is 100 - 300 SCCM, and the heating rate is 2 - 10 °C / min.
8. The preparation method of the nitrogen-doped manganese tetraoxide material according to claim 1, characterized in that In Step 3, the calcination treatment is carried out for 1 - 3 h.
9. A nitrogen - doped manganese tetraoxide material is prepared by the preparation method of the nitrogen - doped manganese tetraoxide material according to any one of claims 1 - 8.
10. Use of the nitrogen - doped manganese tetraoxide material according to claim 9 in an electrochemical energy storage device.