Conjugated naphthone diimide compounds, their preparation methods and applications

Abstract

This invention provides conjugated naphthone diimide compounds, belonging to the field of electrochemical energy storage and energy conversion technology. The structural formulas of the compounds are shown in any one of formulas 1 to 3. Electrode materials prepared from these compounds exhibit excellent electrochemical stability, high specific capacity, good rate performance, and excellent cycle life, making them suitable for novel energy storage systems such as zinc-ion batteries and aluminum-ion batteries. This invention also provides a method for preparing and applying conjugated naphthone diimide compounds.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage and energy conversion technology, and specifically relates to conjugated naphthone diimide compounds, their preparation methods and applications. Background Technology

[0002] With the continued growth of global energy demand and increasingly stringent environmental requirements, traditional fossil fuels are gradually being replaced by renewable energy sources, making the efficient storage and utilization of energy a key focus of current scientific research. While lithium-ion batteries are widely used due to their high energy density and good cycle performance, their high cost, resource scarcity, and potential safety hazards limit their application in large-scale energy storage. In contrast, aqueous zinc / aluminum ion batteries have become a promising research area due to their abundant material sources, low production costs, high safety, and environmental friendliness.

[0003] However, the performance of electrode materials in aqueous zinc / aluminum ion batteries still faces bottlenecks, especially for organic electrode materials. Traditional organic electrode materials, due to their short-range conjugated molecular structure and low molecular weight, suffer from poor conductivity, insufficient redox active sites, and unstable electrochemical performance, limiting their application in high-efficiency energy storage devices. Improving their conductivity, redox activity, and cycle stability through precise molecular structure design and optimization of the conjugated framework has become crucial to solving these current problems. Summary of the Invention

[0004] To address the poor performance of existing organic electrode materials, this invention provides conjugated naphthone diimide compounds. Electrode materials prepared from these compounds exhibit excellent electrochemical stability, high specific capacity, good rate performance, and excellent cycle life, making them suitable for novel energy storage systems such as zinc-ion batteries and aluminum-ion batteries.

[0005] The present invention also provides a method for preparing and applying conjugated naphthone diimide compounds.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides conjugated naphthone diimide compounds, the structural formula of which is shown in any one of formulas 1 to 3:

[0008]

[0009] Calculations show that the theoretical specific capacities of the compounds shown in formulas 1-3 are 260 mAh g, respectively. -1 347mAh g -1 374mAh g -1 The theoretical specific capacity is calculated using the following formula:

[0010]

[0011] Since the method for calculating the theoretical specific capacity of a compound is known in the art, it will not be described in detail here.

[0012] Based on the same inventive concept, the present invention provides a method for preparing conjugated naphthone diimide compounds, the method comprising:

[0013] 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds were dissolved together in an acidic solvent and then subjected to dehydration condensation to obtain a mixture.

[0014] The mixture was subjected to solid-liquid separation, and the resulting solid was washed and vacuum dried to obtain a crude product.

[0015] The crude product was purified in nitric acid solution to obtain conjugated naphthone and diimide compounds.

[0016] Furthermore, the step of dissolving 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds together in an acidic solvent and then performing dehydration condensation to obtain a mixture specifically includes:

[0017] 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds were dissolved together in an acidic solvent, and then dehydrated and condensed at 90℃ to 110℃ for 22 to 26 hours to obtain a mixed solution.

[0018] Furthermore, the o-phenylenediamine compounds include any one of o-phenylenediamine, 2,3-diaminophenazine, and 2,3-diaminonaphthalene-1,4-dione;

[0019] The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to the o-phenylenediamine compound is 1:2.

[0020] Furthermore, the acidic solvent is a mixed solution of acetic acid and ethanol in a volume ratio of 1:1;

[0021] The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to the volume of the acidic solvent is (1-2) mmol: 120 mL.

[0022] Furthermore, the solid-liquid separation of the mixture, followed by washing and vacuum drying of the resulting solid to obtain a crude product, specifically includes:

[0023] The mixture was subjected to solid-liquid separation. The resulting solid was washed several times by centrifugation with hot acetic acid and deionized water, and then vacuum dried at 60±80℃ to obtain the crude product.

[0024] The temperature of the hot acetic acid is 70–90°C.

[0025] Furthermore, the step of purifying the crude product in a nitric acid solution to obtain conjugated naphthone diimide compounds specifically includes:

[0026] The crude product was placed in a 20-40 wt% nitric acid solution and purified at 120-140 °C for 5-10 h to obtain conjugated naphthone diimide compounds.

[0027] The ratio of the mass of the crude product to the volume of the nitric acid solution is (100-200) mg: 200 mL.

[0028] Based on the same inventive concept, this invention provides the application of conjugated naphthone diimide compounds in the preparation of organic electrodes or aqueous zinc / aluminum ion batteries.

[0029] Based on the same inventive concept, the present invention provides an aqueous zinc / aluminum ion battery, wherein the aqueous zinc / aluminum ion battery contains the above-mentioned conjugated naphthone diimide compound.

[0030] Based on the same inventive concept, this invention provides a method for preparing a positive electrode for an aqueous zinc / aluminum ion battery, the method comprising:

[0031] The conductive additive, the binder, and the above-mentioned conjugated naphthone diimide compound are co-dispersed in a solvent to obtain a dispersion.

[0032] The dispersion is coated onto a current collector and dried under vacuum to obtain the positive electrode of an aqueous zinc / aluminum ion battery.

[0033] Furthermore, the step of dispersing the conductive additive, the binder, and the aforementioned conjugated naphthone diimide compound together in a solvent to obtain a dispersion specifically includes:

[0034] The conductive additive, binder and the above-mentioned conjugated naphthone diimide compound were co-dispersed in NMP and then ground into a slurry to obtain a dispersion.

[0035] The conductive additive includes at least one of Ketjen black, Super P, and carbon nanotubes; at least one of Ketjen black, Super P, and carbon nanotubes.

[0036] The adhesive includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, and SBR rubber.

[0037] Furthermore, the step of coating the dispersion onto the current collector and then vacuum drying to obtain the aqueous zinc / aluminum ion battery cathode specifically includes:

[0038] The dispersion was coated onto the surface of a current collector titanium foil and vacuum dried at 90–100°C for 10–14 h to obtain the positive electrode of an aqueous zinc / aluminum ion battery.

[0039] Based on the same inventive concept, the present invention also provides a method for preparing an aqueous zinc / aluminum ion battery, wherein the aqueous zinc / aluminum ion battery uses a conjugated naphthone diimide electrode as the positive electrode, a metallic zinc / aluminum foil as the negative electrode, a glass fiber separator to separate the positive electrode and the negative electrode, and then an electrolyte is added to assemble it into a button battery.

[0040] The conjugated naphthone diimide electrode is prepared by the above-mentioned method for preparing a positive electrode of an aqueous zinc / aluminum ion battery.

[0041] The electrolyte uses zinc perchlorate or aluminum perchlorate as the electrolyte and deionized water as the solvent.

[0042] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0043] 1. This invention relates to conjugated naphthone diimide compounds, which are conjugated compounds containing C=O and C=N structural units. These compounds possess multiple redox active sites, effectively enhancing the multi-electron transfer capability of the material and significantly improving its redox potential and electronic conductivity. When applied to the preparation of battery cathodes, the abundant C=O and C=N groups provide redox active sites, achieving the desired Zn… 2+ And Al 3+ The reversible storage significantly improves the electrochemical specific capacity of the electrode material and exhibits excellent cycle stability. At the same time, the π-conjugated structure within the compound molecule effectively inhibits the dissolution of the electrode material in the electrolyte, ensuring that it still has rapid electron transfer and ion diffusion capabilities under low temperature conditions, thus endowing the battery with excellent low-temperature electrochemical performance.

[0044] 2. This invention relates to conjugated naphthone diimide compounds, which achieve multi-electron redox processes through optimized molecular structure and electronic configuration. This unique conjugated molecular arrangement not only improves conductivity but also optimizes the storage capacity of zinc and aluminum ions. When used to prepare cathode materials, these compounds exhibit excellent energy storage performance in aqueous zinc / aluminum ion batteries, with a theoretical specific capacity greater than 350 mAh g⁻¹. -1 In practical applications, this material is found in 0.2A g. -1 It exhibits 235 mAh g at a current density. -1 It exhibits high reversible capacity and, in aqueous aluminum-ion batteries, can provide approximately 200 mAh g⁻¹ at the same current density. -1The reversible capacity demonstrates excellent energy storage capability. In addition, the cathode material also exhibits excellent rate performance and low-temperature cycling performance, and can maintain stable electrochemical performance at high rates, making it suitable for the preparation of aqueous zinc / aluminum ion batteries.

[0045] 3. The present invention provides a method for preparing conjugated naphthone diimide compounds. The conjugated naphthone diimide compounds prepared by this method have abundant C=O and C=N structural units. The synergistic effect of multiple electroactive centers C=O and C=N enhances the electron transfer capability of the material, thereby enabling the battery to achieve higher electrochemical activity and energy density during discharge. Especially in aqueous environments, the extended aromatic conjugated structure further enhances the dissolution stability of the material, effectively inhibiting the dissolution of the material in aqueous electrolytes, thereby significantly improving the structural stability and cycle life of the electrode material. This method has low production costs and good environmental characteristics, and can be widely used in the manufacture of future high-energy-density energy storage devices. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a scanned image of the naphthone diimide organic electrode material obtained in Example 2 of the present invention;

[0048] Figure 2 The Fourier transform infrared spectrum of the naphthone diimide organic electrode material obtained in Example 2 of this invention;

[0049] Figure 3 The naphthone diimide organic electrode material obtained in Example 2 of this invention was used at 0.2 A g. -1 Electrochemical cycle diagram of a room-temperature aqueous zinc-ion battery at current density;

[0050] Figure 4 The naphthone diimide organic electrode material obtained in Example 2 of this invention was used at 0.2 A g. -1 Constant current charge-discharge curves of a room-temperature aqueous zinc-ion battery at current density.

[0051] Figure 5 This is an electrochemical rate diagram of a room-temperature aqueous zinc-ion battery using the naphthone-diimide organic electrode material obtained in Example 2 of this invention.

[0052] Figure 6 The naphthone diimide organic electrode material obtained in Example 2 of this invention was used at 0.2 A g.-1 Cyclic diagram of an aqueous zinc-ion battery at low current density (-50℃);

[0053] Figure 7 The naphthone diimide organic electrode material obtained in Example 2 of this invention was tested at 0.2 mV s. -1 Cyclic voltammetry curves of a room-temperature aqueous zinc-ion battery at scan rate.

[0054] Figure 8 The naphthone diimide organic electrode material obtained in Example 2 of this invention was used at 0.2 A g. -1 Electrochemical cycle diagram of a room-temperature aqueous aluminum-ion battery at current density;

[0055] Figure 9 The naphthone diimide organic electrode material obtained in Example 2 of this invention was used at 0.2 A g. -1 Constant current charge-discharge curves of a room-temperature aqueous aluminum-ion battery at current density. Detailed Implementation

[0056] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0057] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0058] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0059] The technical principle of this invention is as follows:

[0060] The present invention discloses a method for preparing conjugated naphthone diimide compounds, the method comprising:

[0061] S1. Dissolve 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds together in an acidic solvent and then perform dehydration condensation to obtain a mixture;

[0062] S2. The mixture is subjected to solid-liquid separation, and the resulting solid is washed and vacuum dried to obtain a crude product;

[0063] S3. The crude product is purified in nitric acid solution to obtain conjugated naphthone and diimide compounds.

[0064] Step S1 specifically includes:

[0065] 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds were dissolved together in an acidic solvent, and then dehydrated and condensed at 90℃ to 110℃ for 22 to 26 hours to obtain a mixed solution.

[0066] Furthermore, the o-phenylenediamine compounds include any one of o-phenylenediamine, 2,3-diaminophenazine, and 2,3-diaminonaphthalene-1,4-dione;

[0067] The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to the o-phenylenediamine compound is 1:2.

[0068] In this invention, the advantage of having a molar ratio of 1:2 for the 1,4,5,8-naphthotetracarboxylic dianhydride and the o-phenylenediamine compound is that this molar ratio ensures that all 1,4,5,8-naphthotetracarboxylic dianhydride molecules can fully react with the o-phenylenediamine compound, thereby maximizing the generation of the target product. Furthermore, this ratio helps to improve reaction efficiency and reduce the residue of unreacted substances.

[0069] Furthermore, the acidic solvent is a mixed solution of acetic acid and ethanol in a volume ratio of 1:1;

[0070] The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to the volume of the acidic solvent is (1-2) mmol: 120 mL.

[0071] In this invention, the advantage of using a 1:1 volume ratio mixture of acetic acid and ethanol as the acidic solvent is that acetic acid is a highly polar acidic solvent, capable of effectively dissolving many organic and inorganic compounds, while ethanol has good solubility and low polarity. Using acetic acid and ethanol in a 1:1 ratio forms a mixed solvent system with both polar and non-polar properties, further improving solubility and ensuring the complete dissolution and uniform dispersion of reactants. Furthermore, the mixed solution of acetic acid and ethanol promotes the chemical reaction while suppressing certain unwanted side reactions.

[0072] Step S2 specifically includes:

[0073] The mixture was subjected to solid-liquid separation. The resulting solid was washed several times by centrifugation with hot acetic acid and deionized water, and then vacuum dried at 60±80℃ to obtain the crude product.

[0074] The temperature of the hot acetic acid is 70–90°C.

[0075] In this invention, the advantage of washing the obtained solid material several times by centrifugation with acetic acid at 70-90°C and deionized water is that acetic acid, under high-temperature conditions, can effectively dissolve and remove organic impurities or byproducts in the solid material. This process helps to purify the material surface, making it purer. The use of high-temperature acetic acid helps to activate the material surface, making the surface structure more regular by dissolving unstable surface substances. This has a positive impact on the material's performance in subsequent reactions or applications. After washing with acetic acid, a small amount of acidic substances may remain on the material surface. Washing with deionized water multiple times can effectively neutralize and remove these acidic residues, avoiding adverse effects on the material's performance.

[0076] Step S3 specifically includes:

[0077] The crude product was placed in a 20-40 wt% nitric acid solution and then subjected to an oxidation reaction at 120-140 °C for 5-10 h to obtain conjugated naphthone diimide compounds.

[0078] The ratio of the mass of the crude product to the volume of the nitric acid solution is (100-200) mg: 200 mL.

[0079] In this invention, the advantage of placing the crude product in a 20-40 wt% nitric acid solution is that the nitric acid solution can oxidize and remove certain unwanted small organic molecule impurities, improving the purity of the product. This purification effect helps to improve the performance and quality of the final material. The advantage of carrying out the purification reaction at 120-140°C is that at this temperature, solubility and reactivity increase, making it easier for impurities to separate from the target product, thereby improving the purification effect. This helps to more effectively remove impurities that are difficult to remove from the solution.

[0080] The conjugated naphthone diimide compounds of this application, their preparation methods, and applications will be described in detail below with reference to examples and experimental data.

[0081] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0082] In the following examples, battery performance testing was conducted using the Newway Battery Testing System and the Princeton Electrochemical Workstation. Low-temperature testing required placing the battery in a -50°C low-temperature test chamber.

[0083] Example 1

[0084] This embodiment provides a method for preparing conjugated naphthone diimide compounds, specifically including:

[0085] Step 1: Using 1,4,5,8-naphthalenetetracarboxylic acid dianhydride (1 mmol) and 2,3-diaminonaphthalene-1,4-dione (2 mmol) as raw materials, the crude product was obtained by high-temperature dehydration condensation reaction in an acidic solvent (120 mL). The acidic solvent was a 1:1 volume ratio mixture of acetic acid and ethanol. Nitrogen gas (N2) was introduced as an inert gas for protection. The reaction temperature was 100 °C and the reaction time was 24 hours.

[0086] Step 2: After the obtained mixture is filtered, the solid product is washed 5 times each with hot acetic acid (80℃) and deionized water by centrifugation. The solid product is then dried under vacuum at 60℃.

[0087] Step 3: The crude product (150 mg) obtained in Step 2 was refluxed at 140 °C for 3 h with 30 wt% nitric acid (200 mL), washed 5 times by centrifugation with deionized water, and dried under vacuum at 60 °C to obtain the organic compound shown in Formula 3.

[0088] Furthermore, the synthesis method of the compound of formula (1) is as follows:

[0089] Step 1: Using 1,4,5,8-naphthalenetetracarboxylic acid dianhydride (1 mmol) and o-phenylenediamine (2 mmol) as raw materials, the crude product was obtained by high-temperature dehydration condensation reaction in an acidic solvent; the acidic solvent was a 1:1 volume ratio mixture of acetic acid and ethanol (120 mL), nitrogen (N2) was introduced as an inert gas for protection, the reaction temperature was 100℃, and the reaction time was 24 hours;

[0090] Step 2: After the obtained mixture is filtered, the solid product is washed 5 times each with hot acetic acid (80℃) and deionized water by centrifugation. The solid product is then dried under vacuum at 60℃.

[0091] Step 3: The crude product obtained in Step 2 (150 mg) was refluxed at 140 °C for 3 h with 30 wt% nitric acid (200 mL), washed 5 times by centrifugation with deionized water, and dried under vacuum at 60 °C to obtain the organic compound shown in Formula (1).

[0092] The synthesis method of compound (2) is as follows:

[0093] Step 1: Using 1,4,5,8-naphthalenetetracarboxylic acid dianhydride (1 mmol) and 2,3-diaminophenazine (2 mmol) as raw materials, the crude product was obtained by high-temperature dehydration condensation reaction in an acidic solvent; the acidic solvent was a 1:1 volume ratio mixture of acetic acid and ethanol (120 mL), nitrogen (N2) was introduced as an inert gas for protection, the reaction temperature was 100℃, and the reaction time was 24 hours;

[0094] Step 2: After the obtained mixture is filtered, the solid product is washed 5 times each with hot acetic acid (80℃) and deionized water by centrifugation. The solid product is then dried under vacuum at 60℃.

[0095] Step 3: The crude product obtained in Step 2 (150 mg) was refluxed at 140 °C for 3 h with 30 wt% nitric acid (200 mL), washed 5 times by centrifugation with deionized water, and dried under vacuum at 60 °C to obtain the organic compound shown in formula (2).

[0096] Example 2

[0097] The compounds obtained in the above examples, Ketjen black, and polyvinylidene fluoride (PVDF) were mixed with N-methylpyrrolidone (NMP) solution at a mass ratio of 60:30:10 and ground into a well-dispersed slurry in an agate mortar. This slurry was then uniformly coated onto a titanium foil current collector and vacuum-dried at 80°C for 12 hours to prepare the working electrode (i.e., naphthone-diaimide organic electrode material). Using the working electrode as the positive electrode, zinc foil as the negative electrode, and a glass fiber membrane as the separator, a 2032 button cell was assembled using 3M zinc perchlorate (Zn(ClO4)2). The test voltage range was 0.4V-1.6V vs Zn / Zn. 2+ .

[0098] Furthermore, the method for preparing the positive electrode of an aluminum-ion battery is as follows:

[0099] The compounds obtained in the above examples, Ketjen black, and polyvinylidene fluoride (PVDF) were mixed with N-methylpyrrolidone (NMP) solution at a mass ratio of 60:30:10 and ground into a well-dispersed slurry in an agate mortar. This slurry was then uniformly coated onto a titanium foil current collector and vacuum-dried at 80°C for 12 hours to prepare the working electrode (i.e., naphthone-diaimide organic electrode material). Using the working electrode as the positive electrode, zinc foil as the negative electrode, and a glass fiber membrane as the separator, a 2032 button cell was assembled using 1M Al(ClO4)3 solution as the electrolyte. The test voltage range was 0.2-1.05 vS Al / Al. 3+ .

[0100] Figure 1 This is a scanning electron microscope image of the naphthone diimide organic electrode material (Formula 3) obtained in this embodiment. The material exhibits a distinct rod-like structure, demonstrating its microscopic morphological characteristics during the preparation process.

[0101] Figure 2The Fourier transform infrared (FTIR) spectrum of the naphthone diimide organic electrode material (Formula 3) obtained in this embodiment is shown. The FTIR spectrum reveals that the NH stretching vibration peak in 2,3-diaminonaphthalene-1,4-dione is significantly weakened or disappears, indicating that the amino group participated in the reaction and formed a new bond. The CN vibration peak appears in the spectrum of the final product, indicating the formation of the imide structure. These peak changes indicate that the raw material has been successfully converted into the target product, the naphthone diimide organic electrode material.

[0102] Figure 3 The three compounds shown in Formulas 1-3 were demonstrated at 0.2 A g. -1 Electrochemical cycling performance of room-temperature aqueous zinc-ion batteries at current density. It can be seen that with increasing cycle number, the capacity retention rate of compound 3 (Equation 3) electrode material is high during charge and discharge, with a coulombic efficiency approaching 100%. This indicates that the material has good cycle stability and high coulombic efficiency during long cycles, while compounds 1 (Equation 1) and 2 (Equation 2) exhibit different degrees of capacity decay, especially compound 1, whose capacity decay is more significant, indicating that its structure may have undergone irreversible changes during cycling.

[0103] Figure 4 The constant current charge-discharge curves of the three compounds show that the discharge curve of compound 3 has a relatively obvious plateau around 0.8V. The voltage corresponding to the plateau reflects the main electrochemical reaction process of the naphthone diimide organic electrode material in the aqueous zinc-ion battery, which is usually related to the insertion and extraction behavior of zinc ions. The voltage plateaus of compounds 1 and 2 fluctuate more, especially the discharge plateau of compound 1, which is lower, indicating that its energy storage capacity is limited.

[0104] Figure 5 The electrochemical rate performance of three compounds as cathodes in aqueous zinc-ion batteries at room temperature is shown. The data indicate that the electrode material maintains good specific capacity and stable coulombic efficiency at different rates, especially at high rates, demonstrating excellent rate performance and cycle stability. Compounds 1 and 2, however, exhibit low capacity at high current densities, particularly at 20 A g. -1 At that time, compound 1 almost lost its capacity.

[0105] Figure 6 Three compounds were demonstrated at 0.2 A g. -1 Cycling performance of aqueous zinc-ion batteries at low temperature (-50℃) under varying current densities was investigated. The results show that even at extremely low temperatures, the electrode material exhibits a high specific capacity and very stable capacity retention. In contrast, compounds 2 and 1 have lower specific capacities, maintaining around 85 mAh g⁻¹. -1and 55mAh g -1 This indicates that compound 3 possesses superior electrochemical stability and energy storage capacity at low temperatures.

[0106] Figure 7 Three compounds were demonstrated at 0.2 mV s. -1 Cyclic voltammetry (CV) curves of a room-temperature aqueous zinc-ion battery at the scan rate are shown. Two pairs of distinct redox peaks are clearly visible in the figure, indicating that the material exhibits good redox reactivity during electrochemical processes. These two peaks correspond to Zn... 2+ The insertion and extraction processes verified the reversible zinc storage performance of the material. These two pairs of reversible redox reactions can be attributed to zinc association / dissociation processes occurring on the C=O and C=N groups. In comparison, the redox peaks of compounds 1 and 2 are more dispersed and have lower peak currents, reflecting poorer reversibility and charge transfer kinetics. Compound 3 exhibits higher electrochemical reactivity and can more effectively promote the electrode reaction process.

[0107] Figure 8 Three compounds were demonstrated at 0.2 A g. -1 Electrochemical cycling performance of this electrode material as the cathode in a room-temperature aqueous aluminum-ion battery at the specified current density. The figure shows that the specific capacity of this electrode material is approximately 200 mAh g⁻¹. -1 Furthermore, it maintained good capacity stability over multiple cycles, demonstrating its excellent electrochemical stability. In contrast, the specific capacity of compound 1 remained at only 100 mAh g⁻¹. -1 The value of approximately [value missing] indicates poor electrochemical performance during long-term cycling, potentially suggesting significant side reactions. This result demonstrates that the material exhibits excellent cycling performance in aqueous aluminum-ion batteries, maintaining a high specific capacity over extended periods of cycling.

[0108] Figure 9 Three compounds were demonstrated at 0.2 A g. -1 Charge-discharge curves at current density. Compound 3 exhibits two distinct voltage plateaus and a specific capacity close to 200 mAh g⁻¹. -1 Compound 1 exhibited excellent voltage stability and high energy density, demonstrating the best electrochemical performance. In contrast, compounds 2 and 1 had lower voltage plateaus and lower specific capacities than compound 3.

[0109] In summary, the naphthone diimide organic electrode material (compound 3) prepared in this invention exhibits excellent electrochemical performance when applied as a cathode material in aqueous zinc / aluminum ion batteries.

[0110] Compared with existing technologies, the advantages of this invention are as follows:

[0111] 1. Significantly improved electrochemical performance: By introducing multiple electroactive centers (such as C=O and C=N groups), multi-electron redox processes are effectively realized, the redox potential is increased, and the electronic conductivity of the material is enhanced, thereby significantly improving the specific capacity and rate performance of the electrode.

[0112] 2. Excellent cycle stability: The introduction of extended aromatic conjugated structure significantly reduces the dissolution problem of the material in aqueous environment, enhances its structural stability, and ensures the performance stability of the battery during long-term cycle use, making it suitable for aqueous zinc-ion and aluminum-ion battery applications.

[0113] 3. High reversible capacity: The organic cathode material of this invention has a capacity of 0.2 A g. -1 Achieving 235mAh g at a current density -1 High reversible capacity, and exhibits 200mAh g in aqueous aluminum-ion batteries. -1 Its reversible capacity demonstrates excellent energy storage capabilities.

[0114] 4. Broad application prospects: The organic electrode material of this invention is suitable for aqueous zinc / aluminum ion batteries, especially for aqueous zinc-ion and aluminum-ion batteries. It has low production cost, environmental protection characteristics and high energy storage efficiency, and can be widely used in future high energy density energy storage devices.

[0115] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0116] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0117] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A conjugated naphthone diimide compound, characterized in that, The structural formula of the compound is shown in Formula 3:

2. The method for preparing the conjugated naphthone diimide compound as described in claim 1, characterized in that, The preparation method includes: 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds were dissolved together in an acidic solvent and then subjected to dehydration condensation to obtain a mixture. The mixture was subjected to solid-liquid separation, and the resulting solid was washed and vacuum dried to obtain a crude product. The crude product was purified in nitric acid solution to obtain conjugated naphthone and diimide compounds.

3. The method for preparing conjugated naphthone diimide compounds according to claim 2, characterized in that, The step of dissolving 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds together in an acidic solvent and then performing dehydration condensation to obtain a mixture specifically includes: 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and o-phenylenediamine compounds were dissolved together in an acidic solvent, and then dehydrated and condensed at 90℃ to 110℃ for 22 to 26 hours to obtain a mixed solution.

4. The method for preparing the conjugated naphthone diimide compound according to claim 3, characterized in that, The o-phenylenediamine compound is 2,3-diaminonaphthalene-1,4-dione; The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride and the o-phenylenediamine compound is 1:2; The acidic solvent is a mixed solution of acetic acid and ethanol in a volume ratio of 1:1; The molar ratio of the 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to the volume of the acidic solvent is (1-2) mmol: 120 mL.

5. The method for preparing conjugated naphthone diimide compounds according to claim 2, characterized in that, The solid-liquid separation of the mixture, followed by washing and vacuum drying of the resulting solid, yields a crude product, specifically comprising: The mixture was subjected to solid-liquid separation. The resulting solid was washed several times by centrifugation with hot acetic acid and deionized water, and then vacuum dried at 60±80℃ to obtain the crude product. The temperature of the hot acetic acid is 70–90°C; The step of purifying the crude product in a nitric acid solution to obtain conjugated naphthone diimide compounds specifically includes: The crude product was placed in a 20-40 wt% nitric acid solution and purified at 120-140 °C for 5-10 h to obtain conjugated naphthone diimide compounds. The ratio of the mass of the crude product to the volume of the nitric acid solution is (100-200) mg: 200 mL.

6. The application of the conjugated naphthone diimide compound as described in claim 1 in the preparation of organic electrodes or aqueous zinc / aluminum ion batteries.

7. An aqueous zinc / aluminum ion battery, characterized in that, The aqueous zinc / aluminum ion battery contains the conjugated naphthone diimide compound as described in claim 1.

8. A method for preparing a positive electrode for an aqueous zinc / aluminum ion battery, characterized in that, The preparation method includes: The conductive additive, the binder, and the conjugated naphthone diimide compound of claim 1 are dispersed together in a solvent to obtain a dispersion. The dispersion is coated onto a current collector and dried under vacuum to obtain the positive electrode of an aqueous zinc / aluminum ion battery.

9. The method for preparing an aqueous zinc / aluminum ion battery cathode according to claim 8, characterized in that, The step of dispersing the conductive additive, the binder, and the conjugated naphthone diimide compound of claim 1 together in a solvent to obtain a dispersion specifically includes: The conductive additive, the binder, and the conjugated naphthone diimide compound of claim 1 are co-dispersed in N-methylpyrrolidone, and then ground into a slurry to obtain a dispersion. The conductive additive is at least one of Ketjen Black, Super P, and carbon nanotubes. The adhesive is at least one of polyvinylidene fluoride, polytetrafluoroethylene, and SBR rubber; The process of coating the dispersion onto a current collector and then vacuum drying to obtain an aqueous zinc / aluminum ion battery cathode specifically includes: The dispersion was coated onto the surface of a current collector titanium foil and vacuum dried at 90–100°C for 10–14 h to obtain the positive electrode of an aqueous zinc / aluminum ion battery.

10. A method for preparing an aqueous zinc / aluminum ion battery, characterized in that, The aqueous zinc / aluminum ion battery uses a conjugated naphthone diimide electrode as the positive electrode, a metallic zinc / aluminum foil as the negative electrode, and a glass fiber separator to separate the positive and negative electrodes. Electrolyte is then added and assembled into a button cell. The conjugated naphthone diimide electrode is prepared by the method for preparing an aqueous zinc / aluminum ion battery positive electrode as described in claim 8 or 9. The electrolyte uses zinc perchlorate or aluminum perchlorate as the electrolyte and deionized water as the solvent.

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