A hydrogen bond-stabilized bipolar organic small-molecule cathode material, a preparation method and application thereof

Abstract

This invention provides a hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method, and its application, comprising the following steps: weighing a conductive agent and a binder, adding a solvent, and grinding uniformly to obtain a slurry; uniformly coating the slurry onto a current collector; and drying to obtain the cathode material.

Description

Technical Field

[0001] This invention relates to the field of chemical power source technology, specifically to a hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method, and its application. Background Technology

[0002] Against the backdrop of the urgent pursuit of sustainable energy solutions, developing practical and economical energy storage devices has become a core strategy for addressing the contemporary energy crisis and environmental protection issues. Aqueous zinc-ion batteries, with their unique advantages of high theoretical capacity and low redox potential, are considered important candidates for future energy storage technologies, demonstrating enormous application potential. However, the development of zinc batteries still faces severe challenges such as slow kinetics, limited capacity, and poor cycle stability, which seriously restrict their full performance.

[0003] Given that the energy storage efficiency of aqueous zinc-ion batteries is highly dependent on the interaction between redox active motifs and charge carriers, designing and optimizing cathode materials with multiple active sites has become a key path to improve battery performance. Against this backdrop, small organic molecules, due to their advantages such as resource renewability, structural designability, and functional customizability, have rapidly emerged in the field of zinc-organic batteries, offering new possibilities for achieving high-efficiency energy storage.

[0004] Among numerous types of organic cathode materials, bipolar organic compounds ingeniously combine the high capacity of n-type organics with the high discharge voltage of p-type organics, effectively overcoming the limitations of single-type materials and providing a fast and stable solution for zinc-ion storage. However, in practical applications, these materials still face problems such as poor resistance to dissolution, insufficient structural stability, and low conductivity, leading to sluggish reaction kinetics and shortened cycle life, thus limiting the further development of zinc-organic batteries. To overcome this challenge, it is urgent to design bipolar organic cathode materials with high stability and high-density redox active sites. Summary of the Invention

[0005] This invention is made to solve the above-mentioned problems, and aims to provide a hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method and application, which has high stability and high density of bipolar redox cluster active sites.

[0006] This invention provides a method for preparing a hydrogen-bonded stable bipolar organic small molecule cathode material, characterized by the following features:

[0007] Weigh Conductive agents and binders are added to a solvent and ground evenly to obtain a slurry. The slurry is then evenly coated onto a current collector and dried to obtain the positive electrode material.

[0008] The method for preparing the hydrogen-bonded stable bipolar organic small molecule cathode material provided by this invention may also have the following characteristic: wherein, The mass ratio of conductive agent to adhesive is (6-7):(2-3):1.

[0009] The method for preparing hydrogen-bonded stable bipolar organic small molecule cathode material provided by the present invention may also have the following characteristics: wherein the drying temperature is 70-90℃ and the drying time is 10-14h.

[0010] The method for preparing hydrogen-bonded stable bipolar organic small molecule cathode material provided by the present invention may also have the following feature: wherein the conductive agent is any one of graphite, carbon black or acetylene black.

[0011] The method for preparing hydrogen-bonded stable bipolar organic small molecule cathode material provided by the present invention may also have the following characteristics: wherein the binder is polytetrafluoroethylene and the solvent is any one of N-methylpyrrolidone, dimethylformamide or ethanol.

[0012] The method for preparing hydrogen-bonded stable bipolar organic small molecule cathode material provided by the present invention may also have the following feature: wherein the current collector is any one of titanium foil, nickel mesh, titanium mesh, stainless steel mesh or carbon paper.

[0013] The present invention also provides a hydrogen-bonded stable bipolar organic small molecule cathode material, characterized by being prepared by a method for preparing hydrogen-bonded stable bipolar organic small molecule cathode materials.

[0014] This invention also provides an application of a hydrogen-bonded stable bipolar organic small molecule cathode material in assembling the cathode of an aqueous zinc-ion battery.

[0015] In the application of the hydrogen-bonded stable bipolar organic small molecule cathode material provided by this invention in assembling the cathode of an aqueous zinc-ion battery, it can also have the following characteristics: wherein the hydrogen-bonded stable bipolar organic small molecule cathode material is used as the cathode of the battery, high-purity commercial zinc foil with a zinc content of ≥99.99% is used as the anode, filter paper or glass fiber is used as the filter paper, a separator is placed between the cathode and the anode, and after being arranged, it is placed in the battery case, and then the electrolyte is added.

[0016] In the application of the hydrogen-bonded stable bipolar organic small molecule cathode material provided by the present invention in assembling the cathode of an aqueous zinc-ion battery, it may also have the following characteristics: wherein the electrolyte is one or more of Zn(CF3SO3)2, ZnCl2 or ZnSO4 aqueous solution.

[0017] The role and effect of invention

[0018] According to the present invention, a hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method, and its application, the present invention introduces highly redox-active p-type -NH motifs and n-type C=O groups into organic cathode materials. This not only promotes reversible electrochemical processes but also significantly enhances reaction kinetics. Simultaneously, by constructing an intermolecular hydrogen bond network, the structural stability of organic molecules can be significantly enhanced, reducing capacity loss and ensuring the persistence of charge transport. Furthermore, the extended π-conjugated molecular structure effectively promotes electron delocalization between molecules, improving the overall conductivity of the material and accelerating charge storage. Attached Figure Description

[0019] Figure 1 Scanning electron microscope image of 5,12-dihydroquinolino[2,3-b]acridin-7,14-dione;

[0020] Figure 2 A schematic diagram of hydrogen bonding in the small organic molecule 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione;

[0021] Figure 3 The band gap of 5,12-dihydroquinolino[2,3-b]acridin-7,14-dione;

[0022] Figure 4 This is a rate performance diagram of the aqueous zinc-organic battery in Example 1 of the present invention;

[0023] Figure 5 This is a cycle stability diagram of the aqueous zinc-organic battery in Example 1 of the present invention at a current density of 2A / g;

[0024] Figure 6 This is a rate performance diagram of the aqueous zinc-organic battery in Example 2 of the present invention;

[0025] Figure 7 This is a rate performance diagram of the aqueous zinc-organic battery in Example 3 of the present invention;

[0026] Figure 8 This is a cycle stability diagram of the aqueous zinc-organic battery in Example 3 of the present invention at a current density of 2A / g. Detailed Implementation

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] 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 hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method and application.

[0029] Example 1

[0030] This embodiment describes a method for preparing a hydrogen-bonded stable bipolar organic small molecule cathode material, comprising the following steps:

[0031] 0.03g 0.015g of acetylene black conductive agent and 0.005g of polytetrafluoroethylene adhesive were mixed in a mass ratio of 6:3:1. Then, 70μL of N-methylpyrrolidone was added and the mixture was ground for 30 minutes to obtain a slurry. The slurry was then uniformly coated onto a 1.2cm diameter titanium foil current collector using a blade, with a mass loading of approximately 2.8mg / cm². –1 The cathode material was then dried in an 80°C vacuum oven for 12 hours.

[0032] In this embodiment, the prepared battery positive electrode is further used to assemble an aqueous zinc-organic battery, as detailed below:

[0033] Using the prepared battery as the positive electrode and high-purity commercial zinc foil (zinc content ≥99.99%) as the negative electrode, a GE-Whatman glass fiber separator is placed between the positive and negative electrodes. After being arranged, the battery is placed in a CR2032 button cell battery case, and then 3M Zn(CF3SO3)2 electrolyte is added to assemble an aqueous zinc-organic battery.

[0034] All raw materials used in this embodiment are commercially available reagent-grade products.

[0035] In this embodiment, the electrochemical performance of the prepared aqueous zinc-organic battery was also tested, including testing the energy storage performance of the device using a CHI660E electrochemical workstation. Cycle and rate performance tests were performed on a LAND CT2001A battery testing system. The voltage window was 0.2–1.6V.

[0036] Figure 1 This is a scanning electron microscope image of 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione in Example 1 of the present invention.

[0037] like Figure 1 As shown, the small organic molecule 5,12-dihydroquinolino[2,3-b]acridin-7,14-dione has a regular rod-shaped geometry.

[0038] Figure 2 This is a schematic diagram of the hydrogen bonds of the hydrogen-bonded stable 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione organic molecule in Example 1 of the present invention.

[0039] like Figure 2 As shown, the hydrogen-bonded stable 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione organic small molecule designed in this embodiment has a nitrogen heterocyclic π-conjugated aromatic structure and contains multiple redox-active carbonyl / imine sites, which can form an NH···O type hydrogen bond network.

[0040] Figure 3 It is the band gap of 5,12-dihydroquinolino[2,3-b]acrid-7,14-dione in Example 1 of the present invention.

[0041] like Figure 3 As shown, 5,12-dihydroquinolino[2,3-b]acridin-7,14-dione has an ultra-low band gap of 1.97 eV, which is much lower than that of most organic electrode materials. This indicates that the small organic molecule has high conductivity, which is beneficial for its better charge transfer efficiency and lower kinetic hindrance when applied to batteries, thus promoting redox reactions.

[0042] Figure 4 The diagram shows the rate performance of the zinc-organic battery assembled in Example 1 of this invention using a 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione organic small molecule positive electrode, a zinc foil negative electrode, and a Zn(CF3SO3)2 aqueous electrolyte.

[0043] like Figure 4 As shown, the aqueous zinc-organic battery prepared in this embodiment has a specific capacity of over 212 mAh / g when charged and discharged at 0.2 A / g, and a rate capacity of over 146 mAh / g when charged and discharged at 10 A / g, demonstrating high specific capacity storage performance.

[0044] Figure 5 This is a cycle stability diagram of a zinc-organic battery assembled in Example 1 of the present invention using a 5,12-dihydroquinoline[2,3-b]acridin-7,14-dione organic small molecule positive electrode, a zinc foil negative electrode, and a Zn(CF3SO3)2 aqueous electrolyte at a current density of 2 A / g.

[0045] like Figure 5 As shown, the aqueous zinc-organic battery prepared in this embodiment retains 71.2% of its capacity after 20,000 charge-discharge cycles, demonstrating excellent cycle stability.

[0046] Example 2

[0047] In this embodiment, based on the preparation conditions of Example 1, 0.03g The 0.015g acetylene black conductive agent and 0.005g polytetrafluoroethylene adhesive are replaced with: 0.035g 0.01g of graphite conductive agent and 0.005g of polytetrafluoroethylene adhesive.

[0048] In this embodiment, the electrochemical performance of the prepared aqueous zinc-organic battery was tested, including testing the energy storage performance of the device using a CHI660E electrochemical workstation. Cycle and rate performance tests were performed on a LAND CT2001A battery testing system with a voltage window of 0.2–1.6V.

[0049] Figure 6 This is a rate performance diagram of the aqueous zinc-organic battery in Example 2 of the present invention. Figure 6 As shown, the aqueous zinc-organic battery prepared in this embodiment has a specific capacity of over 200 mAh / g when charged and discharged at 0.2 A / g, and a rate capacity of over 131 mAh / g when charged and discharged at 10 A / g, demonstrating high specific capacity storage performance.

[0050] Example 3

[0051] In this embodiment, based on the preparation conditions of Example 1, when assembling an aqueous zinc-organic battery using the prepared battery cathode, the electrolyte of the aqueous zinc-organic battery is replaced with ZnSO4.

[0052] Figure 7 This is a rate performance diagram of the aqueous zinc-organic battery in Example 3 of the present invention. Figure 7 As shown, the aqueous zinc-organic battery prepared in this embodiment has a specific capacity of over 206 mAh / g when charged and discharged at 0.2 A / g, and a rate capacity of 121 mAh / g when charged and discharged at 10 A / g.

[0053] Figure 8 This is a cycle stability diagram of the aqueous zinc-organic battery in Example 3 of the present invention at a current density of 2 A / g. (See diagram below.) Figure 8 As shown, the aqueous zinc-organic battery prepared in this embodiment has a capacity retention rate of 68.3% after 20,000 charge-discharge cycles, indicating good cycle stability.

[0054] The role and effect of the embodiments

[0055] According to the present invention, a hydrogen-bonded stable bipolar organic small molecule cathode material, its preparation method, and its application, the present invention introduces highly redox-active p-type -NH motifs and n-type C=O groups into organic cathode materials. This not only promotes reversible electrochemical processes but also significantly enhances reaction kinetics. Simultaneously, by constructing an intermolecular hydrogen bond network, the structural stability of organic molecules can be significantly enhanced, reducing capacity loss and ensuring the persistence of charge transport. Furthermore, the extended π-conjugated molecular structure effectively promotes electron delocalization between molecules, improving the overall conductivity of the material and accelerating charge storage.

[0056] It is a heterocyclic organic molecule containing nitrogen and oxygen elements. It can form a stable NH···O type hydrogen bond network between molecules. At the same time, the π-conjugated planar structure is highly extended, which not only helps to improve the material's resistance to dissolution in electrolyte solution, but also promotes the efficient dispersion of electrons in the entire molecular skeleton, thereby effectively reducing the kinetic energy barrier in the redox reaction process, improving charge transfer efficiency, and improving battery performance.

[0057] When used as the positive electrode active material in aqueous zinc-organic batteries, it can react with Zn in the electrolyte. 2 + / CF3SO3 - The battery assembled using alternating coordination exhibits a specific capacity exceeding 212 mAh / g at 0.2 A / g charge / discharge and a rate capacity exceeding 146 mAh / g at 10 A / g charge / discharge, demonstrating high specific capacity storage performance. Furthermore, after 20,000 charge-discharge cycles, the capacity retention rate is over 70%, showcasing high specific capacity, energy density, and superior cycle stability. The prepared cathode material can achieve mixed anion-cation co-coordination during the electrochemical reaction process. The two n-type carbonyl groups are coupled with the cation at a lower potential, and the two imine groups are coordinated with the anion in a higher potential range. This not only achieves rapid redox reaction kinetics, which is beneficial to significantly improving battery capacity, but also effectively inhibits the dissolution of the cathode material and improves battery stability.

[0058] The main raw materials for the preparation of the positive electrode material of the present invention are widely available, low in cost 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.

[0059] 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. The application of a hydrogen-bonded stable bipolar organic small molecule cathode material in assembling the cathode of an aqueous zinc-ion battery, characterized in that: The preparation method of hydrogen-bonded stable bipolar organic small molecule cathode material includes the following steps: Weigh Conductive agents and binders are added, and solvents are added to uniformly grind to obtain a slurry. The slurry is then uniformly coated onto a current collector, and after drying, the positive electrode material is obtained. Among them, the The mass ratio of conductive agent and adhesive is (6-7):(2-3):

1.

2. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in assembling the cathode of an aqueous zinc-ion battery, characterized in that: in, The drying temperature is 70-90℃, and the drying time is 10-14 hours.

3. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in assembling the cathode of an aqueous zinc-ion battery, characterized in that: in, The conductive agent is graphite or carbon black.

4. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in assembling the cathode of an aqueous zinc-ion battery, characterized in that: in, The conductive agent is graphite or acetylene black.

5. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in assembling the cathode of an aqueous zinc-ion battery, characterized in that: in, The adhesive is polytetrafluoroethylene, and the solvent is any one of N-methylpyrrolidone, dimethylformamide, or ethanol.

6. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in assembling the cathode of an aqueous zinc-ion battery, characterized in that: in, The current collector is any one of titanium foil, nickel mesh, titanium mesh, stainless steel mesh, or carbon paper.

7. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 1 in the assembly of the cathode of an aqueous zinc-ion battery, characterized in that, in, The hydrogen-bonded stable bipolar organic small molecule cathode material is used as the positive electrode of the battery, high-purity commercial zinc foil with a zinc content of ≥99.99% is used as the negative electrode, filter paper or glass fiber is used as the filter paper, a separator is placed between the positive and negative electrodes, and after being arranged, it is placed in the battery case, and then the electrolyte is added.

8. The application of the hydrogen-bonded stable bipolar organic small molecule cathode material according to claim 7 in the assembly of the cathode of an aqueous zinc-ion battery, characterized in that, in, The electrolyte is one or more of Zn(CF3SO3)2, ZnCl2, or ZnSO4 aqueous solution.

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