A multi-electron tetranitroporphyrin active material, an organic cathode material, and an aqueous zinc battery

Abstract

This invention provides a multi-electron tetranitroporphyrin active material, an organic cathode material, and an aqueous zinc battery. The process involves dissolving pyrrole and 4-nitrobenzaldehyde in chloroform and heating the solution, then sequentially adding a boron trifluoride diethyl ether complex, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone. The reaction solution is then evaporated, washed, dried, and purified to obtain the multi-electron tetranitroporphyrin active material. This active material, along with a graphite conductive agent and a polytetrafluoroethylene binder, is mixed, and then N-methylpyrrolidine is added. The mixture is then uniformly ground and coated onto a current collector, followed by drying to obtain the organic cathode material. This organic cathode material is then used to assemble an aqueous zinc battery. The organic cathode material containing the multi-electron tetranitroporphyrin active material designed in this invention serves as a highly redox-active and stable cathode material for aqueous zinc batteries, significantly improving the specific capacity, energy density, and cycle stability of organic cathode materials.

Description

Technical Field

[0001] This invention belongs to the field of chemical power source technology, specifically relating to a multi-electron tetranitroporphyrin active material, an organic cathode material, and an aqueous zinc battery. Background Technology

[0002] To address environmental degradation and the increasingly severe energy shortage, the development of new energy sources is crucial. Batteries, as highly efficient electrochemical energy storage devices, are experiencing rapid growth driven by demand from portable consumer electronics and medical devices, electric vehicles, power grids, high-power military applications, and the Internet of Things (IoT) and wearable technologies. Aqueous zinc-ion batteries, with their advantages of being environmentally friendly, low-cost, non-toxic, simple to assemble, and safe, represent a new type of "green battery." Zinc metal possesses abundant resources and high stability, exhibiting a high theoretical specific capacity (820 mAh / g) and a high volumetric theoretical specific capacity (5851 mAh / cm³). 2 With its low redox voltage (-0.76V vs. standard hydrogen electrode), it is suitable as the negative electrode for aqueous batteries. Meanwhile, organic positive electrode materials have received widespread attention from the scientific and industrial communities due to their structural and functional diversity and abundant resources.

[0003] The functional groups in organic materials exhibit high reactivity, enabling them to undergo redox reactions with zinc ions and achieve energy storage and output. Based on the charge properties of these functional groups, organic materials can be classified into n-type, p-type, and bipolar types. n-type organic materials typically include quinones, imines, nitroaromatics, nitrile compounds, and azo compounds. Most of these organic materials exhibit high specific capacity but low operating potential (<0.8V vs. Zn / Zn). 2+ This is due to the inherently high energy level of its lowest unoccupied molecular orbital. Although a very small number of quinone compounds provide high discharge voltages (1.1 V), their high solubility in the discharge state leads to irreversible capacity loss; although p-type organic materials have high redox potentials (>1.0 V vs. Zn / Zn), 2+ While zinc batteries exhibit high capacity and fast reaction kinetics, their low density of active sites and single-electron group reactions result in limited capacity output (<150 mAh / g). In contrast, n / p hybrid bipolar organic materials combine the high capacity-voltage advantages of both n-type and p-type reactions, overcoming their respective limitations, and show promising application prospects in energy storage. However, bipolar organic materials are still in the early stages of research, facing challenges such as insufficient capacity (<200 mAh / g), low energy density (<150 Wh / kg), and / or limited cycle life (<5000 charge-discharge cycles) due to their low redox active unit density and single-electron reactions per active group. Therefore, developing highly active multi-electron bipolar organic materials is crucial for improving zinc battery performance. Summary of the Invention

[0004] This invention addresses the aforementioned problems and aims to provide a multi-electron tetranitroporphyrin active material, an organic cathode material, and an aqueous zinc battery. To achieve this objective, this invention designs a multi-electron tetranitroporphyrin cathode material, which, as a highly redox-active and stable cathode material for aqueous zinc batteries, significantly improves the specific capacity, energy density, and cycle stability of organic cathode materials.

[0005] This invention provides a multi-electron tetranitroporphyrin active substance, characterized by the following chemical structural formula:

[0006] The multi-electron tetranitroporphyrin active material provided by this invention may also have the following characteristic: the preparation method of the multi-electron tetranitroporphyrin active material includes the following steps:

[0007] Step 1: Dissolve pyrrole and 4-nitrobenzaldehyde in chloroform to obtain a mixed solution; Step 2: Heat the mixed solution and add boron trifluoride diethyl ether complex, triethylamine and 2,3-dicyano-5,6-dichlorobenzoquinone in sequence to react and obtain a crude product solution; Step 3: Evaporate the crude product solution to obtain a crude product, wash, dry and purify the crude product to obtain a multi-electron tetranitroporphyrin active substance.

[0008] The multi-electron tetranitroporphyrin active material provided by the present invention may also have the following characteristics: wherein the mass ratio of pyrrole, 4-nitrobenzaldehyde, chloroform, boron trifluoride diethyl ether complex, triethylamine and 2,3-dicyano-5,6-dichlorobenzoquinone is 1:(2-4):(500-1000):(0.5-1):(0.5-1):(3-4).

[0009] The multi-electron tetranitroporphyrin active material provided by this invention may also have the following characteristics: in step one, the dissolution condition is stirring at room temperature; in step two, the heating condition is heating under reflux at 50-80°C and reacting for 1-6 hours; in step three, the evaporation condition is evaporation at 30-80°C for 2-6 hours, the washing condition is anhydrous methanol, the drying condition is vacuum drying at 50-80°C for 3-6 hours, and the purification condition is purification using dichloromethane.

[0010] The present invention also provides an organic cathode material having the following characteristics: comprising a multi-electron tetranitroporphyrin active material as described above.

[0011] The organic cathode material provided by this invention may also have the following characteristics: the preparation method of the organic cathode material includes the following steps: Step 1, mixing multi-electron tetranitroporphyrin active material, graphite and polytetrafluoroethylene, and adding N-methylpyrrolidine and grinding uniformly to obtain a slurry; Step 2, uniformly coating the slurry onto the current collector, and drying it to obtain the organic cathode material.

[0012] The organic cathode material provided by this invention may also have the following characteristics: in step one, the mass ratio of the multi-electron tetranitroporphyrin active material, graphite, polytetrafluoroethylene and N-methylpyrrolidine is (4-7):(2-1):1:2; in step two, the current collector is one of titanium foil, nickel mesh, titanium mesh, stainless steel mesh and carbon paper, and the drying conditions are drying in a vacuum oven at 80°C for 12 hours.

[0013] The present invention also provides an aqueous zinc battery, characterized by being assembled using any of the above-mentioned organic cathode materials.

[0014] The aqueous zinc battery provided by the present invention may also have the following features: the preparation method of the aqueous zinc battery includes the following steps: using an organic positive electrode material as the positive electrode and metallic zinc as the negative electrode, placing a separator between the positive electrode and the negative electrode, arranging it and placing it in the battery case, adding electrolyte and assembling it into a battery.

[0015] The aqueous zinc battery provided by this invention may also have the following characteristics: the purity of metallic zinc is ≥99.99%; the separator is one of filter paper and glass fiber; the electrolyte is one or more of ZnCl2, ZnSO4 or Zn(CF3SO3)2 aqueous solution, and the concentration of the electrolyte is 1-10M.

[0016] The role and effect of invention

[0017] According to the multi-electron tetranitroporphyrin active material, organic cathode material, and aqueous zinc battery of the present invention, the active material is obtained by dissolving pyrrole and 4-nitrobenzaldehyde in chloroform and heating, then sequentially adding boron trifluoride diethyl ether complex, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone. The reaction solution is then evaporated, washed, dried, and purified to obtain the multi-electron tetranitroporphyrin active material. The multi-electron tetranitroporphyrin active material, graphite conductive agent, and polytetrafluoroethylene binder are mixed, and N-methylpyrrolidine is added. The mixture is then uniformly ground and coated onto a current collector. After drying, the organic cathode material is obtained. Subsequently, an aqueous zinc battery is assembled using the organic cathode material.

[0018] The organic cathode material containing multi-electron tetranitroporphyrin active material designed in this invention serves as a highly redox-active and stable cathode material for aqueous zinc-ion batteries, significantly improving the specific capacity, energy density, and cycle stability of organic cathode materials. Attached Figure Description

[0019] Figure 1 This is a scanning electron microscope image of the multi-electron tetranitroporphyrin active substance prepared in Example 1 of the present invention;

[0020] Figure 2 This is a scanning electron microscope image of the multi-electron tetranitroporphyrin active substance prepared in Example 2 of the present invention;

[0021] Figure 3 This is a charge-discharge curve of a zinc battery assembled with a positive electrode containing a multi-electron tetranitroporphyrin active material, a zinc foil negative electrode, and a ZnSO4 electrolyte under different current densities, as shown in Embodiment 3 of the present invention.

[0022] Figure 4 This is a cycle stability diagram of a zinc battery assembled in Embodiment 3 of the present invention using a positive electrode containing a multi-electron tetranitroporphyrin active material, a zinc foil negative electrode, and a ZnSO4 electrolyte at a current density of 10 A / g. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a tetranitroporphyrin active material and its preparation method, organic cathode material and aqueous zinc battery of this invention.

[0024] <Example 1>

[0025] This embodiment provides a multi-electron tetranitroporphyrin active substance, the chemical structural formula of which is as follows:

[0026] The preparation method of the multi-electron tetranitroporphyrin active substance is as follows:

[0027] Step 1: Dissolve pyrrole and 4-nitrobenzaldehyde in chloroform at room temperature with stirring to obtain a mixed solution;

[0028] Step two: The mixed solution was heated under reflux at 60°C, and boron trifluoride diethyl ether complex, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone were added sequentially. The mixture was reacted for 2 hours to obtain the crude product solution.

[0029] The mass ratio of pyrrole, 4-nitrobenzaldehyde, chloroform, boron trifluoride diethyl ether, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone is 1:2.5:1000:0.8:0.7:3.

[0030] Step 3: The crude product solution was evaporated at 50°C for 3 hours to obtain the crude product. The crude product was washed with anhydrous methanol, dried at 70°C for 5 hours, and purified with dichloromethane to obtain the multi-electron tetranitroporphyrin active substance.

[0031] The raw materials used in this embodiment are all commercially available reagent-grade products.

[0032] Figure 1 This is a scanning electron microscope image of the multi-electron tetranitroporphyrin active material prepared in Example 1 of the present invention, which shows that the material exhibits a nanosheet structure.

[0033] <Example 2>

[0034] This embodiment provides a multi-electron tetranitroporphyrin active substance, the chemical structural formula of which is as follows:

[0035] The preparation method of the multi-electron tetranitroporphyrin active substance is as follows:

[0036] Step 1: Dissolve pyrrole and 4-nitrobenzaldehyde in chloroform at room temperature with stirring to obtain a mixed solution;

[0037] Step two: The mixed solution was heated under reflux at 60°C, and boron trifluoride diethyl ether complex, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone were added sequentially. The mixture was reacted for 1 hour to obtain the crude product solution.

[0038] The mass ratio of pyrrole, 4-nitrobenzaldehyde, chloroform, boron trifluoride diethyl ether, triethylamine, and 2,3-dicyano-5,6-dichlorobenzoquinone is 1:2.25:1000:0.74:0.52:3.4.

[0039] Step 3: After evaporating the crude product solution at 40°C for 6 hours, the crude product is obtained. The crude product is washed with anhydrous methanol, dried at 70°C for 5 hours, and purified with dichloromethane to obtain the multi-electron tetranitroporphyrin active substance.

[0040] The raw materials used in this embodiment are all commercially available reagent-grade products.

[0041] Figure 2 This is a scanning electron microscope image of the multi-electron tetranitroporphyrin active material prepared in Example 2 of the present invention, which shows that the material exhibits a nanosheet structure.

[0042] <Example 3>

[0043] This embodiment provides an organic cathode material and an aqueous zinc battery, and tests the electrochemical performance of the prepared aqueous zinc battery.

[0044] The preparation process of the organic cathode material is as follows: The multi-electron tetranitroporphyrin active material, graphite, polytetrafluoroethylene and N-methylpyrrolidine obtained in Example 1 were weighed according to the mass ratio of 6:2:1:2 and put into a mortar and ground evenly for 30 minutes. Then, the slurry was evenly coated onto a stainless steel mesh current collector with a diameter of about 1.2 cm with a blade (the current collector is one of titanium foil, nickel mesh, titanium mesh, stainless steel mesh or carbon paper. In this example, stainless steel mesh current collector is selected). It was placed in an 80℃ vacuum oven and dried for 12 hours to obtain the organic cathode material to be assembled.

[0045] The preparation process of the aqueous zinc battery is as follows: Using the prepared organic positive electrode material as the positive electrode, and a zinc sheet with a purity of not less than 99.99% as the negative electrode, a separator (filter paper or glass fiber; in this embodiment, a GE-Whatman glass fiber separator is used) is placed between the positive and negative electrodes. A 3M ZnSO4 solution is used as the electrolyte (the electrolyte is one or more of ZnCl2, ZnSO4, and Zn(CF3SO3)2 aqueous solutions, with an electrolyte concentration of 1-10M; in this embodiment, a 3M ZnSO4 solution is used). After preparation, the electrolyte is placed in a battery casing and assembled to obtain the aqueous zinc battery. During operation, the Zn in the zinc battery electrolyte... 2+ The charge carrier undergoes a coordination reaction with the redox-active nitro group and secondary amine group of tetranitroporphyrin to achieve charge storage.

[0046] The raw materials used in this embodiment are all commercially available reagent-grade products.

[0047] Electrochemical performance testing included testing the energy storage performance of the device using a CHI660E electrochemical workstation, and performing cycle and rate performance tests on a LAND CT3001A battery testing system with a voltage window of 0.5–1.7V.

[0048] Figure 3 This is a charge-discharge curve diagram of a zinc battery assembled in Embodiment 3 of the present invention, using a positive electrode containing a multi-electron tetranitroporphyrin active material, a zinc foil negative electrode, and a ZnSO4 electrolyte, at different current densities. In this embodiment, the zinc battery assembled at a charge-discharge current density of 0.2 A / g achieves a specific capacity of 338 mAh / g, an average discharge voltage of 1.08 V, and an energy density of 365 Wh / kg. Furthermore, at a charge-discharge current density of 20 A / g, the rate capacity reaches 155 mAh / g, demonstrating high specific capacity storage performance.

[0049] Figure 4 This is a cycle stability diagram of a zinc battery assembled with a positive electrode containing a multi-electron tetranitroporphyrin active material, a zinc foil negative electrode, and a ZnSO4 electrolyte in an embodiment of the present invention at a current density of 10 A / g. The capacity retention rate of the zinc battery assembled in this embodiment after 50,000 charge-discharge cycles is 71.6%.

[0050] The role and effect of the embodiments

[0051] As can be seen from Examples 1 to 3, the multi-electron tetranitroporphyrin active material designed and synthesized in this invention possesses a quadruple n-type nitro functional group (electron acceptor) and dual p-type secondary amine groups (electron donor), enabling it to provide multiple redox active centers coupled with zinc ions, achieving high-capacity and high-voltage charge storage. Furthermore, the tetranitroporphyrin has an extended π-conjugated macrocyclic structure, which can inhibit its dissolution in the electrolyte and significantly extend battery life.

[0052] During the electrochemical reaction process of the battery, the n-type nitro group of the tetranitroporphyrin cathode reacts with Zn. 2+ A quadruple topological coordination reaction occurs in the low-voltage region, where the p-type secondary amine group reacts with SO4. 2- A dual coordination reaction occurs in the high-voltage region to form a stable organic coordination structure, thereby achieving its anti-dissolution effect in the electrolyte and solving the problem that current organic small molecule cathode materials are easily dissolved in the electrolyte, resulting in insufficient battery cycle life.

[0053] The multi-electron tetranitroporphyrin active material prepared by the method of this invention, when used as a positive electrode material for aqueous zinc-ion batteries, shows through analysis and testing that its specific capacity exceeds 338 mAh / g at a charge / discharge rate of 0.2 A / g, and its rate capacity exceeds 120 mAh / g at a charge / discharge rate of 20 A / g, demonstrating high specific capacity storage performance. After 50,000 charge-discharge cycles, the capacity retention rate is over 70%, pushing the overall energy storage performance of zinc-ion batteries to a new level.

[0054] In addition, the main raw materials used in this invention are widely available, inexpensive and environmentally friendly. The entire electrode and electrolyte preparation process is carried out at room temperature and pressure, which is simple to operate and safe and pollution-free.

[0055] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An organic cathode material, characterized in that, A water-based zinc battery: The organic positive electrode material comprises a multi-electron tetranitro porphyrin active substance, and a chemical structural formula of the multi-electron tetranitro porphyrin active substance is:

2. The organic positive electrode material according to claim 1, characterized in that: The preparation method of the organic positive electrode material comprises the following steps: Step one, mix the multi-electron tetranitroporphyrin active substance, graphite and polytetrafluoroethylene, and add N-methyl pyrrolidine for uniform grinding to obtain a slurry; Step two, uniformly coat the slurry on a current collector, and dry to obtain the organic positive electrode material.

3. The organic positive electrode material of claim 2, characterized in that: wherein The preparation method of the organic positive electrode material comprises the following steps: In step one, the mass ratio of the multi-electron tetranitroporphyrin active substance, graphite, polytetrafluoroethylene and N-methyl pyrrolidine is (4-7) : (2-1) : 1 :

2. In step two, the current collector is one of titanium foil, nickel mesh, titanium mesh, stainless steel mesh and carbon paper, and the drying condition is 80℃ vacuum oven drying for 12h.

4. The organic positive electrode material of claim 1, characterized in that: wherein, The preparation method of the multi-electron tetranitroporphyrin active substance comprises the following steps: Step one, dissolve pyrrole and 4-nitrobenzaldehyde in chloroform to obtain a mixed solution; Step two, heat the mixed solution, and sequentially add boron trifluoride diethyl ether complex, triethylamine and 2,3-dicyano-5,6-dichloroquinone for reaction to obtain a crude product solution; Step three, evaporate the crude product solution to obtain a crude product, wash, dry and purify the crude product to obtain the multi-electron tetranitroporphyrin active substance.

5. The organic positive electrode material of claim 4, characterized in that: wherein The mass ratio of pyrrole, 4-nitrobenzaldehyde, chloroform, boron trifluoride diethyl ether complex, triethylamine and 2,3-dicyano-5,6-dichloroquinone is 1: (2-4) : (500-1000) : (0.5-1) : (0.5-1) : (3-4).

6. The organic positive electrode material of claim 4, characterized in that: wherein The preparation method of the multi-electron tetranitroporphyrin active substance comprises the following steps: In step one, the dissolving condition is room temperature stirring, In step two, the heating condition is heating reflux at 50-80℃ for 1-6h, In step three, the evaporation condition is evaporation at 30-80℃ for 2-6h, the washing uses anhydrous methanol, the drying condition is vacuum drying at 50-80℃ for 3-6h, and the purification condition is purification using dichloromethane.

7. An aqueous zinc battery, characterized by: The organic positive electrode material of any one of claims 1-6 is used for assembly.

8. The water-based zinc battery of claim 7, characterized in that: wherein The preparation method of the water-based zinc battery comprises the following steps: The organic positive electrode material is used as a positive electrode, metal zinc is used as a negative electrode, a separator is placed between the positive electrode and the negative electrode, and after being arranged, the battery is placed in a battery shell, an electrolyte is added, and the battery is assembled.

9. The water-based zinc battery of claim 8, characterized in that: wherein The purity of the metal zinc is ≥99.99%; The separator is one of filter paper and glass fiber; The electrolyte is one or several of ZnCl2, ZnSO4 or Zn(CF3SO3)2 aqueous solution, and the concentration of the electrolyte is 1-10M.

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