An organic-inorganic composite positive electrode material, a preparation method and application thereof

Abstract

This invention belongs to the field of electrochemical energy storage technology, specifically relating to an organic-inorganic composite cathode material, its preparation method, and its applications. An organic carbonyl compound and a transition metal oxide are dispersed in a mixed solvent and stirred until a homogeneous mixture is obtained. The homogeneous mixture is then subjected to a solvothermal reaction. After the reaction, the resulting product is washed and dried to obtain the organic-inorganic composite cathode material. This invention constructs an organic-inorganic synergistic composite cathode structure. The inorganic material provides a framework that enables the organic molecules to become more ordered and expose more active sites. It also acts as an electron donor to rapidly activate oxygen, greatly improving the efficiency of air self-charging and achieving electron-ion coupling regulation at the cathode interface. After being exposed to air for 1 hour, the battery spontaneously recovers to an open-circuit voltage of 1.21V and exhibits a discharge capacity at a current density of [value missing].

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology, specifically relating to an organic-inorganic composite cathode material, its preparation method, and its application. Background Technology

[0002] Air-based self-charging aqueous zinc-ion batteries are a novel energy storage system capable of spontaneous energy recovery using oxygen from ambient air. They combine the inherent safety, low cost, and environmental friendliness of aqueous electrolytes, making them promising for applications in self-powered energy storage devices. These batteries typically use zinc or zinc-based materials as the negative electrode and a positive electrode material capable of reversible redox reactions as the energy storage carrier, achieving voltage recovery through oxygen reduction reactions in an air environment. However, existing air-based self-charging zinc-ion batteries generally suffer from slow self-charging rates, insufficient open-circuit voltage recovery, and limited cycle stability in practical applications. The root causes lie in the slow reaction kinetics at the positive electrode interface and the difficulty in coordinating electron and ion transport processes.

[0003] Existing research indicates that organic aromatic compounds containing active groups such as carbonyl and imine groups possess abundant redox sites as cathode materials for aqueous zinc-ion batteries, but they generally suffer from insufficient electronic conductivity and structural degradation during cycling. Related patents CN102683756B and CN111934029B propose polymer and zinc-organic cathode systems, respectively, which improve capacity output to some extent, but are still limited by insufficient electron transport capability and capacity decay at high rates.

[0004] In the inorganic system field, CN102110858B and CN107221716B employ vanadium oxide and its nanostructure as cathode materials to achieve… Reversible insertion / extraction exists, but a trade-off remains between rate performance and structural stability. Furthermore, CN113937266B... Composite strategies improve conductivity and specific surface area, but still do not fundamentally solve the problem of synergistic optimization of electron transport and ion diffusion within the system.

[0005] In summary, a single inorganic oxide or organic cathode system cannot simultaneously achieve oxygen adsorption and activation, rapid electron transport, and... Highly efficient migration is crucial; simple composite systems struggle to construct stable interfacial coupling structures through physical mixing. Therefore, how to construct an organic-inorganic synergistic structure at the cathode interface that combines efficient electron transport and rapid ion migration capabilities while enhancing oxygen adsorption / activation efficiency, in order to achieve electron-ion coupling regulation during air self-charging, remains a critical technical challenge that urgently needs to be addressed. Summary of the Invention

[0006] To address the problems of slow self-charging rate, insufficient open-circuit voltage recovery, and limited reaction kinetics at the cathode interface in existing air-charged zinc-ion batteries, this invention provides an organic-inorganic composite cathode material, its preparation method, and its applications.

[0007] The technical solution adopted is as follows: A method for preparing an organic-inorganic composite cathode material, wherein an organic carbonyl compound and a transition metal oxide are dispersed in a mixed solvent and continuously stirred until a uniform mixture is obtained, the uniform mixture is subjected to a solvothermal reaction, and after the reaction is completed, the obtained product is washed and dried to obtain the organic-inorganic composite cathode material.

[0008] Preferably, the organic carbonyl compound is a naphthalenetetracarboxylic acid dianhydride compound or its derivatives, and the source of the transition metal oxide includes, but is not limited to, vanadium dioxide and its derived vanadates or mixtures thereof.

[0009] Preferably, the organic carbonyl compound is Transition metal oxides are The mixed solvent is a mixture of water and alcohol solvents.

[0010] Preferably, the mass ratio of the organic carbonyl compound to the transition metal oxide is 0.01-0.03:1.

[0011] Preferably, the solvothermal reaction temperature is 170-200℃ and the reaction time is 10-14h.

[0012] Preferably, the stirring stage is heated in a water bath at a temperature of 120-150℃.

[0013] The organic-inorganic composite cathode material prepared by the above-described preparation method of this application has an organic carbonyl compound uniformly coated and / or partially intercalated in the layered structure of a transition metal oxide.

[0014] Preferably, the proportion of organic carbonyl compounds is 1-3%.

[0015] The organic-inorganic composite cathode material prepared in this application is used in an air-charged aqueous zinc-ion battery.

[0016] Preferably, the air-charged aqueous zinc-ion battery uses zinc or zinc-based materials as the negative electrode and an aqueous zinc salt electrolyte.

[0017] This invention constructs an organic-inorganic synergistic composite cathode structure. The inorganic material provides the framework, enabling the organic molecules to achieve overall ordering and expose more active sites. It then acts as an electron donor to rapidly activate oxygen, significantly improving the efficiency of air self-charging and achieving electron-ion coupling regulation at the cathode interface. Benefiting from these advantages, After being exposed to air for 1 hour, the battery was able to spontaneously recover to its open-circuit voltage of 1.21V. At current density The discharge capacity.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves coupling regulation of electrons and ions at the cathode interface by constructing an organic-inorganic synergistic composite cathode structure. After being exposed to air for 1 hour, the battery was able to spontaneously recover to its open-circuit voltage of 1.21V, and... Achieving high current density The discharge capacity is high, and it can stably charge and discharge for more than 13 cycles without relying on an external power source, demonstrating excellent reversibility and cycle stability.

[0019] 2. The composite cathode material of this invention combines the abundant redox active sites of organic materials with the excellent electron transport capabilities of inorganic materials, which can effectively reduce the interfacial reaction energy barrier and remove the free energy barrier of the rate-limiting step of the oxygen reduction reaction from... Reduce to This improves the air self-charging efficiency and reversible discharge capacity.

[0020] 3. By applying the positive electrode material of this invention to a battery, it can provide up to [amount missing] during the first discharge process. Its specific capacity is significantly higher than that of most reported organic or organic-inorganic composite cathode systems, while its average operating voltage is about 0.7V, exhibiting high energy storage capacity and good energy output characteristics.

[0021] In summary, this invention achieves electron-ion synergistic transport at the positive electrode through organic-inorganic interface regulation, providing a practical and feasible technical solution for constructing a high-efficiency and stable air-charged aqueous zinc-ion battery, with promising application prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the preparation of an organic-inorganic composite cathode material formed by combining an organic carbonyl compound with a transition metal oxide in this invention.

[0023] Figure 2 These are the X-ray diffraction patterns of the organic-inorganic composite cathode material in this invention and the transition metal oxide in the comparative example.

[0024] Figure 3 This is a comparison of the Fourier transform infrared spectra of the organic-inorganic composite cathode material, the comparative organic material, and the inorganic material in this invention.

[0025] Figure 4This is a comparison of the Raman spectra of the organic-inorganic composite cathode material and the comparative inorganic material in this invention.

[0026] Figure 5 These are high-resolution transmission electron microscope images of the organic-inorganic composite cathode material in Example 1 (top left) and the inorganic material in Comparative Example 2 (bottom left); the top right image is a magnified view of the area within the red box in the top left image; the bottom right image is a magnified view of the area within the red box in the bottom left image.

[0027] Figure 6 These are scanning electron microscope (SEM) comparison images of the positive electrode in Example 1 and Comparative Examples 1-3.

[0028] Figure 7 This is the elemental distribution diagram of the organic-inorganic composite cathode in Example 1.

[0029] Figure 8 This is a distribution diagram of organic-inorganic mechanical composite elements in Comparative Example 3 of this invention.

[0030] Figure 9 This is a constant current charge-discharge curve of the organic-inorganic composite cathode in this invention and the organic material of Comparative Example 1; wherein, the overlap of the four charge-discharge cycles in Example 1 is better; the figure captions indicate the number of charge-discharge cycles, such as 1st being the first cycle, 2nd being the second cycle, 3rd being the third cycle, and 4th being the fourth cycle.

[0031] Figure 10 The diagram shows the long-cycle test results of the organic-inorganic composite cathode in Example 1 and the organic material in Comparative Example 1 and the inorganic material in Comparative Example 2.

[0032] Figure 11 This is a rate test chart of the organic-inorganic composite cathode in Example 1 and the organic material in Comparative Example 1 and the inorganic material in Comparative Example 2.

[0033] Figure 12 This is a comparison chart of the rate capability of the organic-inorganic composite cathode in this invention with other batteries. Figure 13 This is a comparison diagram of impedance and GITT between the organic-inorganic composite cathode of this invention and the organic material of Comparative Example 1 and the inorganic material of Comparative Example 2.

[0034] Figure 14 This is a differential charge density distribution diagram at the interface of the organic-inorganic composite cathode material in this invention.

[0035] Figure 15 Comparative Example 1 (NTCDA) and Example 1 ( Composite materials and Comparative Example 2 ( Total density of states and partial density of states plots.

[0036] Figure 16These are constant current charge-discharge curves for characterization under different charge-discharge states in this invention, X-ray diffraction patterns of the cathode material under different charge-discharge states, and Fourier transform infrared spectra of the cathode material under different charge-discharge states, where a, b, and c correspond to three sampling state points of the battery during the charge-discharge process.

[0037] Figure 17 Comparative Example 1 (NTCDA), Comparative Example 2 ( Comparative Example 3 Mechanical mixing) and Example 1 ( ) The change of air self-charging open-circuit voltage (OCV) of the electrode over time.

[0038] Figure 18 The discharge curves of the batteries after different air self-charging times are obtained by mixing the organic-inorganic composite cathode material of Example 1 with the organic material of Comparative Example 1 and the mechanically mixed material of Comparative Example 3.

[0039] Figure 19 This is a comparison chart of the self-charging rate of the organic-inorganic composite cathode in this invention with other batteries.

[0040] Figure 20 This is a graph showing the capacity stability test results of the organic-inorganic composite cathode material in Example 1 during multiple air self-charge-discharge cycles.

[0041] Figure 21 This is a graph showing the capacity stability test results of the organic cathode material in Comparative Example 1 during multiple air self-charge-discharge cycles in this invention.

[0042] Figure 22 This is a graph showing the capacity stability test results of the mechanical hybrid material in Comparative Example 3 during multiple air self-charge-discharge cycles in this invention.

[0043] Figure 23 This is a graph showing the free energy change of the organic-inorganic composite cathode and the comparative organic cathode during the oxygen reduction reaction process in this invention.

[0044] Figure 24 This is a schematic diagram of an air-chargeable zinc-ion battery that powers external electronic devices in this invention.

[0045] In the diagram: Charging indicates charging; Discharging indicates discharging; Self-charging indicates self-charging; AirSelf-charging indicates self-charging in air; This work indicates the present application. The cathode material was prepared according to the scheme of Example 1; the cathode material was prepared according to the scheme of Comparative Example 1 for NTCDA. The cathode material prepared according to Comparative Example 2 is referred to as "the cathode material prepared according to Comparative Example 3". Detailed Implementation

[0046] To facilitate understanding of the present invention, it will be described in more detail below with reference to the accompanying drawings and specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0047] This invention provides a method for preparing an organic-inorganic composite cathode material for an air-chargeable aqueous zinc-ion battery, comprising the following steps: S1. The organic carbonyl compound and the transition metal oxide are added to the solvent, and after stirring (300 rpm, 30 minutes) and water bath heating treatment, a uniformly dispersed first mixed system is obtained; S2. The first mixture system is subjected to ultrasonic treatment to obtain the second mixture system. The second mixture system is transferred to a reaction vessel for solvothermal reaction. After the reaction is completed, the initial product is collected by centrifugation. S3. The initial product is repeatedly washed with deionized water and / or alcohol solvents, and then dried to obtain an organic-inorganic composite cathode material.

[0048] Principle Explanation: Organic carbonyl compounds possess advantages such as multi-electron redox activity and strong structural tunability, but suffer from poor conductivity and easy solubility. Transition metal oxides, on the other hand, exhibit high conductivity and structural stability, but their theoretical capacity improvement potential is limited. This application utilizes a solvothermal reaction process to produce a synergistic effect: transition metal oxides serve as a conductive framework, enhancing the electron transport efficiency of carbonyl materials while suppressing their dissolution in the electrolyte, maintaining good stability in use; organic carbonyl compounds provide additional redox active sites, increasing the overall specific capacity and mitigating the volume expansion problem of transition metal oxides.

[0049] In one embodiment, the mass ratio of the organic carbonyl compound to the transition metal oxide is 0.01-0.03:1.

[0050] In one embodiment, the organic carbonyl compound is a naphthalenetetracarboxylic acid dianhydride compound or its derivative; the source of the transition metal oxide includes, but is not limited to, vanadium pentoxide, vanadium dioxide and its derived vanadates or composite oxides.

[0051] In one embodiment, the organic carbonyl compound is 1,4,5,8-naphthalenetetracarboxylic anhydride (NTCDA), and the transition metal oxide is... .

[0052] In one embodiment, the water bath heating temperature is 120-150℃, and the treatment time is 8-12h; the solvothermal reaction temperature is 170-200℃, and the reaction time is 10-14h.

[0053] In one embodiment, drying is performed by natural drying under an inert atmosphere or vacuum for 12-15 hours.

[0054] The organic-inorganic composite cathode material prepared by the above method is applied in an air-charged aqueous zinc-ion battery.

[0055] In one embodiment, the air-charging aqueous zinc-ion battery uses a zinc sheet or zinc-based material as the negative electrode and an aqueous zinc salt electrolyte as the electrolyte, wherein the zinc salt is zinc sulfate, zinc trifluoromethanesulfonate, or a combination thereof. It has also been found that adding borate buffer additives to the electrolyte further improves interfacial stability and increases the air self-charging rate.

[0056] The positive electrode sheet was prepared by weighing the organic-inorganic composite positive electrode material, conductive agent and binder obtained in Example 1 according to the mass ratio (e.g., active material: conductive agent: binder = 7:2:1), adding an appropriate amount of solvent to prepare a uniform slurry, uniformly coating the slurry on the current collector and drying it to obtain the positive electrode sheet; the corresponding positive electrode sheets of Comparative Examples 1, 2 and 3 were prepared in the same way.

[0057] The assembly of an air-based self-charging aqueous zinc-ion battery uses a zinc sheet or zinc-based material as the negative electrode and the aforementioned positive electrode sheet as the positive electrode. A glass fiber or other separator is used, and an aqueous zinc salt electrolyte is added to assemble the battery. The battery can be a button cell structure or a pouch cell structure.

[0058] Test Methods: The morphology and microstructure of the cathode material were characterized using scanning electron microscopy (SEM); elemental distribution was analyzed using energy-dispersive X-ray spectroscopy (EDS); the material structure was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy; and the changes in the surface chemical state of the material under different conditions were analyzed using X-ray photoelectron spectroscopy (XPS). Electrochemical tests included cyclic voltammetry (CV), constant current charge-discharge, rate performance testing, and cycle stability testing; air self-charging behavior was evaluated by discharging to a set cutoff voltage, exposing the material to air for a certain period of time, and then discharging again / recording the change in open-circuit voltage.

[0059] Example 1: Combination Figure 1 Understand the preparation process of organic-inorganic composite cathode materials formed by combining organic carbonyl compounds with transition metal oxides. First, 9.0 mg NTCDA and 500 mg... Add (mass ratio 0.018:1) to a mixed solvent consisting of 10 mL ethylene glycol and 20 mL deionized water, and magnetically stir for 1 h at room temperature. Then, heat in a water bath for 30 min, followed by further stirring. Heat in a water bath at 130°C for 12 h to ensure thorough mixing, and then ultrasonically disperse for 45 min. Transfer the resulting suspension to a 50 mL PTFE-lined stainless steel reactor and react at 180°C for 12 h. After the reaction, allow it to cool naturally to room temperature. Collect the product by centrifugation and wash it six times alternately with deionized water and anhydrous ethanol. Finally, dry under vacuum at 60°C for 12 h to obtain... Composite materials.

[0060] Example 2: Unlike Example 1, 5 mg NTCDA and 500 mg Add (mass ratio 0.01:1) to a mixed solvent of ethanol and deionized water in a volume ratio of 2:1, and magnetically stir at 300 rpm for 30 minutes at room temperature. Then, heat in a water bath at 120°C for 10 hours to ensure thorough mixing, followed by ultrasonic dispersion for 45 minutes. Transfer the resulting suspension to a 50 mL PTFE-lined stainless steel reactor, and solvothermally react at 170°C for 14 hours. After the reaction, allow it to cool naturally to room temperature. Collect the product by centrifugation and wash it six times alternately with deionized water and anhydrous ethanol. Finally, allow it to air dry under vacuum for 14 hours to obtain the desired product. Composite materials.

[0061] Example 3: Unlike Example 1, 15 mg NTCDA and 500 mg The product was added at a mass ratio of 0.03:1 to a mixed solvent consisting of ethylene glycol and deionized water in a volume ratio of 2:1. The mixture was magnetically stirred at 300 rpm for 30 minutes at room temperature, followed by water bath heating at 150°C for 8 hours to ensure thorough mixing. The mixture was then ultrasonically dispersed for 45 minutes. The resulting suspension was transferred to a 50 ml PTFE-lined stainless steel reactor, and the reaction was carried out at a solvothermal temperature of 200°C for 10 hours. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was collected by centrifugation and washed six times alternately with deionized water and anhydrous ethanol. Finally, it was naturally dried under vacuum for 15 hours to obtain the desired product. Composite materials.

[0062] Comparative Example 1: The organic cathode material was prepared using only the organic carbonyl compound NTCDA as the cathode active material, and the organic cathode material was obtained by the same washing and drying method as in Example 1.

[0063] Comparative Example 2: Inorganic cathode materials were prepared using only transition metal oxide materials. Inorganic cathode materials were obtained as positive electrode active materials using the same washing and drying methods as in Example 1.

[0064] Comparative Example 3: The composite material was prepared by mechanical mixing as the positive electrode active material. The mechanically mixed positive electrode material was obtained by washing and drying in the same way as in Example 1.

[0065] Mix in a mass ratio of 7:2:1 Acetylene black and polytetrafluoroethylene (PTFE) binder were mixed and thoroughly ground to prepare an electrode slurry. The slurry was then uniformly coated onto a stainless steel mesh substrate using a roller coating method and dried under vacuum at 80°C for 8 hours to obtain the positive electrode sheet of this invention. In Comparative Examples 1-3, the corresponding positive electrode sheets were prepared using the same method.

[0066] Combination Figure 2 understand, Figure 2 Example 1 of the organic-inorganic composite cathode material of the present invention ( (Comparative Example 2) and transition metal oxides The X-ray diffraction pattern. As can be seen from the figure, Comparative Example 2 ( ) and Example 1 ( All are in approximately , A distinct diffraction peak appears at this location. The diffraction peaks at these locations can be attributed to the (110), (111), (-311), and (312) crystal planes, respectively. It should be noted that the composite sample still retains [the following characteristics]. The crystal structure characteristics. Compared with Comparative Example 2 ( Compared to Example 1, Example 2 ( The diffraction peak intensity shifted slightly and the peak shape broadened slightly, indicating that the crystallinity of the material decreased after the introduction of NTCDA, but it did not damage the crystallinity. The main crystalline phase indicates that NTCDA has been successfully composited into... in the matrix.

[0067] Combination Figure 3 understand, Figure 3 This is a comparison of the Fourier transform infrared (FT-IR) spectra of the organic-inorganic composite cathode material of the present invention, the organic materials of Comparative Examples 1-2, and the inorganic materials. The FT-IR results further confirm the findings of Example 1 (…). Successful construction of composite materials. Comparative Example 1 (NTCDA) at 1680, 1352, 1123, and 766. The region exhibits a distinct characteristic absorption peak, which can be attributed to the C=O stretching vibration. Compared to Comparative Example 1 (NTCDA), Example 1 ( The aforementioned characteristic peaks were still retained, indicating that the molecular skeleton structure of NTCDA still exists after recombination. It is noteworthy that the C=O characteristic peak changed from 1680... Move to 1640 This indicates that the carbonyl group and There are obvious interface interactions between them. This indicates that NTCDA in Example 1 has been successfully covered. The surfaces form a strong coupling between them.

[0068] Combination Figure 4 understand, Figure 4 This is a comparison of the Raman spectra of the organic-inorganic composite cathode material and the inorganic material of this invention. The Raman test results show that the material prepared in Example 1 of this invention... Composite materials retain The characteristic vibration peaks indicate that the composite process was not damaged. The main structure. Meanwhile, in composite materials... Peak and The relative spacing of the peaks is determined by pure 143.99 The change is 140.39 This indicates that the introduction of the organic component NTCDA has an effect on... The lattice vibrations of the organic and inorganic components exerted a regulatory effect, demonstrating the formation of a stable interfacial coupling structure. This indicates that the present invention can achieve effective composite composition of organic and inorganic components, and contributes to improving the structural stability and interfacial reactivity of the material.

[0069] Combination Figure 5 Understanding, compared to comparative example 2 ( Example 1 () The interlayer spacing of the composite material significantly increased from the original 0.72 nm to 0.93 nm, an increase of approximately 0.21 nm. This change directly confirms the successful insertion of some NTCDA. Between layers.

[0070] Combination Figure 6 It is understood that pure NTCDA exhibits a regular sheet-like structure with a smooth surface and clear edges. However, in Comparative Example 2 (… This manifests as a flower-like or layered aggregate structure loosely assembled from two-dimensional nanosheets. In Example 1 ( In the composite material, the two components exhibit significant structural synergy and morphological reconstruction. NTCDA molecules are not simply attached, but rather uniformly coated... The surface of the nanosheets, and partially embedded in their interlayer voids, leads to The originally loose stacking pattern has been significantly altered. This tight composite state not only makes the overall morphology of the material more ordered, but also effectively increases the surface area and provides more channels for ion migration and electron transport. Comparative Example 3 (mechanically mixed) The fact that no NTCDA molecules were found embedded in the layer indicates that the technical path in this application is irreplaceable.

[0071] Combination Figure 7 and Figure 8 By comparing the elemental distribution maps, it can be directly observed that the three elements C, V, and O are present in Example 1 ( The spatial distribution of the nanoflowers was investigated. The results showed that the elemental signals uniformly covered the entire composite structure, strongly confirming that the NTCDA molecule not only... The surface achieved uniform coating and was successfully embedded within the layered structure. This result corroborates the aforementioned SEM morphology observations, jointly confirming that NTCDA and... The composite is uniform and effective. However, in Comparative Example 3 ( The uniform distribution of C, N, V, and O elements cannot be observed in the elemental distribution diagram of the mechanical mixture, indicating that the mechanically mixed material cannot achieve the desired uniform distribution of NTCDA and... Effective compounding.

[0072] Combination Figure 9 Understanding, in At current density, Example 1 ( The battery can provide up to [amount missing] during the first discharge. The specific capacity, as provided in Example 2, is... The specific capacity, as provided in Example 3, can be... The specific capacity indicates that all three synthetic steps can successfully prepare the product. The cathode exhibits a significantly higher specific capacity than most reported organic or organic-inorganic composite cathode systems. In contrast, the initial discharge specific capacity of Comparative Example 1 (Zn / / NTCDA) battery is only... This indicates that the capacity of the composite material is much greater than that of the NTCDA monomer.

[0073] Combination Figure 10 Understanding. Example 1 ( ) Battery in Under high current density, the battery underwent long-term cycle testing. Even after 500 consecutive charge-discharge cycles, its discharge specific capacity remained stable at [value missing]. The coulombic efficiency remained at 100% throughout, indicating that the electrode possesses excellent cycle stability. This is evident from the performance of Comparative Example 1 (Zn / / NTCDA) cell. The long-cycle results at current density show that the battery maintains approximately [percentage missing] after 500 cycles. The discharge specific capacity. From Comparative Example 2 ( ) Battery in The long-cycle results at current density show that the battery maintains approximately [percentage missing] after 500 cycles. The discharge specific capacity of these components is lower than that of the examples. These results indicate that the composite system of the present invention can effectively improve battery energy storage performance.

[0074] Combination Figure 11 Understand that the embodiment of the present invention prepared in Example 1 ( The electrodes exhibit excellent rate performance at different current densities: The discharge capacity is approximately As the current density increases to 1, 2, 5, 10 The hourly capacity decreased sequentially to approximately 352.3, 284.6, 235.2, and 159.5. When the current density recovers to At that time, the capacity can be restored to approximately The capacity recovery rate was 89%, while the coulombic efficiency remained close to 100%. In contrast, Comparative Example 2 ( Electrode in The discharge capacity is approximately , Decrease to approximately While the comparative example 1 (NTCDA) single electrode in Below only about At high rates, capacity decay is significant. The above data indicates that, through NTCDA and... The composite structure can significantly improve the high-rate capacity retention and reversibility of the electrode, verifying the effectiveness of the technical solution of the present invention.

[0075] Combination Figure 12 Understanding, Example 1 ( (The image above shows the battery and...) Compared with previously reported Zn battery composite cathode materials, Example 1 exhibits higher capacity retention under different current densities. The performance at lower rates is significantly improved.

[0076] Combination Figure 13 Understanding, this invention ( The electrode with the smallest semicircle diameter in the Nyquist curve has a significantly lower charge transfer impedance than Comparative Example 2. The electrodes of Comparative Example 1 (NTCDA) and the electrode of Comparative Example 2 show that the composite structure has low charge transport impedance and can effectively promote interfacial charge transport. Meanwhile, the GITT calculation using the galvanostatic intermittent titration technique yielded... The diffusion coefficient shows that in Example 1 ( The Log D of the electrode during the charging and discharging process is mainly distributed in approximately Within the range, while comparative example 2 ( The electrodes of Comparative Example 1 (NTCDA) are approximately [missing information]. and This indicates that the composite electrode exhibits superior ion diffusion kinetics. Furthermore, Example 1 ( The electrode exhibits a smaller fluctuation in diffusion coefficient throughout the entire charge and discharge process, demonstrating greater stability. Transmission behavior. The above results demonstrate that the method constructed in this invention... Composite structures can effectively reduce charge transport resistance and improve This increases the diffusion rate, thereby significantly improving the electrochemical reaction kinetics performance of the electrode material.

[0077] Combination Figure 14 Understanding is that the charge density difference plot clearly reveals the characteristics of Example 1 ( The redistribution of electrons at the interface of the composite material. In this figure, yellow areas represent electron accumulation, while cyan areas represent electron depletion. This charge distribution indicates that NTCDA molecules and A highly efficient electronic transmission channel is formed between the layers.

[0078] Combination Figure 15 Understand, Comparative Example 1 (NTCDA) and Example 1 ( Composite materials and Comparative Example 2 ( The total density of states and partial density of states of ) were measured. Comparative Example 1 (NTCDA), when not combined with other materials, has a relatively limited electronic structure and weak electron conductivity, making it difficult to effectively participate in charge transfer and electrochemical reactions. In contrast, Example 1 ( The density of states spectrum of the complex shows a significant overlap between the O-2p and V-3d orbitals in the energy range of -5 to 0 eV, indicating that NTCDA and There is a strong orbital overlap.

[0079] Combination Figure 16 Understanding, non-in-situ XRD reveals Structural changes in the composite material during insertion and disengagement. Points a, b, and c correspond to three sampling states of the battery during charging and discharging. During discharge, the diffraction peaks are slightly biased towards higher angles, indicating changes in the interlayer structure. Ions and Strong charge interactions between layers reduce the interlayer spacing. This phenomenon illustrates... The insertion of ions led to The layers generate a charge shielding effect, causing the interlayer spacing to decrease. Conversely, during charging, the diffraction peaks shift to lower angles, indicating that the interlayer spacing is restored and expanded, which further verifies Example 1 ( The composite electrode exhibits good structural reversibility and stability during charge and discharge, providing a structural basis for its excellent cycle performance. Meanwhile, the non-in-situ FT-IR spectrum... The image shows a characteristic peak of the C=O stretching vibration, and changes in this peak value can reflect the electrochemical behavior of the material during charge and discharge. As the electrode is charged from 0.2V to 1.4V, the intensity of the C=O peak gradually increases, and when the electrode discharges back to 0.2V, the intensity of the C=O peak decreases again. This reversible change indicates that during charge and discharge, and The fact that ions can be reversibly inserted into and extracted from C=O groups proves that the carbonyl group is the main redox active site in the system.

[0080] Combination Figure 17 Understand, Comparative Example 1 (NTCDA), Comparative Example 2 ( Comparative Example 3 Mechanical mixing) and Example 1 ( The air self-charging open-circuit voltage (OCV) of the electrode changes over time. Of particular note is Example 1 ( After one hour of air exposure, the OCV value of the composite electrode rapidly increased to 1.21V. This voltage change is significantly higher than that of Comparative Example 2. (0.48V), Comparative Example 1 (NTCDA) (0.99V) and Comparative Example 3 ( Mechanical mixing (0.81V) indicates that Example 1 Composite electrodes can provide higher voltages during air self-charging.

[0081] Combination Figure 18 Understanding, Example 1 ( ) Battery in Discharge curves at current density. The battery's discharge capacity steadily increases with the self-charging time up to 1 hour. Finally, after 1 hour of self-charging, the battery's discharge capacity reaches... However, for Comparative Example 1 (NTCDA) cells, the battery discharge capacity continuously increases with increasing air charging time, reaching only [a certain value] after 1 hour of air exposure. Comparative Example 3 ( (Mechanical hybrid) The capacity of air self-charging in 1 hour is only This indicates that Example 1 The composite electrode can not only quickly restore high voltage, but also maintain efficient capacity output during discharge.

[0082] Combination Figure 19 Understanding, Example 1 ( (The image above shows the battery and...) Compared to conventional batteries, it has an advantage in hourly discharge capacity under different discharge current densities during the self-charging and subsequent discharge process.

[0083] Combination Figure 20 , Figure 21 and Figure 22 Understanding, Example 1 The stability and reversibility of the battery during multiple charge-discharge cycles. After 1 hour of self-charging, the battery... It provides a stable average discharge capacity at a current density. Furthermore, it can stably self-charge in air and subsequently discharge for more than 13 cycles, demonstrating high cycle stability and reversibility, with stable voltage recovery. In contrast, the comparative 1NTCDA battery... Able to continuously output average current density The discharge capacity, compared to the mechanical hybrid cathode material battery in Example 3 Able to continuously output average current density The discharge capacity of both examples is far lower than that of Example 1. Battery.

[0084] Tables 1 and 2 show the results of Example 1 ( Table 1 compares the performance of the Zn / / NTCDA@VO2 battery with existing air-charged zinc-ion batteries. Referring to Table 1, compared to previously reported air-charged zinc-ion batteries, the Zn / / NTCDA@VO2 battery of Example 1 exhibits a shorter self-charging time, demonstrating a technical advantage in short self-charging recovery time. Referring to Table 2, the Zn / / NTCDA@VO2 battery of Example 1 shows advantages in open-circuit voltage and capacity recovery.

[0085] Table 1. Comparison of self-charging time with other self-charging batteries Table 2 Comparison of open-circuit voltage and capacity recovery with other self-charging batteries Combination Figure 23 Understanding, NTCDA and The change in free energy of the oxygen reduction reaction (ORR) at the interface allows for a direct comparison of the differences in reaction kinetics between the two systems, illustrating the composite material's... This improved the interfacial dynamics. For the original NTCDA system, the most challenging step in the ORR process occurred during the initial electron transfer process following oxygen molecule adsorption. The energy barrier for this step is as high as 0.91 eV, indicating that oxygen activation and subsequent reactions are significantly limited in this system, which is one of the important reasons for its relatively slow air self-charging kinetics. In contrast, in In the composite system, the energy barrier of this rate-limiting step is significantly reduced to 0.39 eV, indicating that... The introduction of [a substance] has a significant regulatory effect on the reaction pathway. As an electron donor, it can effectively change the electron distribution at the interface, enhance the adsorption capacity of NTCDA for oxygen molecules, and promote the activation of oxygen molecules, thus enabling the key intermediate to... It is easier to form.

[0086] Combination Figure 24 Understandably, after the air self-charging process, the discharged state... The battery can stably provide continuous power to an electronic thermometer with a rated voltage of 1.5V, indicating that the battery can achieve effective charging and energy output without external energy input. This result directly verifies... The system exhibits excellent air self-charging capability and high energy recovery efficiency. Furthermore, the device maintains reliable operation under actual electronic loads, further highlighting its application potential in self-powered electronic devices and low-power energy systems.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for preparing an organic-inorganic composite cathode material, characterized in that, An organic carbonyl compound and a transition metal oxide are dispersed in a mixed solvent and stirred continuously until a homogeneous mixture is obtained. The homogeneous mixture is subjected to a solvothermal reaction. After the reaction is completed, the resulting product is washed and dried to obtain an organic-inorganic composite cathode material.

2. The method for preparing the organic-inorganic composite cathode material according to claim 1, characterized in that, The organic carbonyl compounds are naphthalenetetracarboxylic acid dianhydrides and their derivatives. The sources of transition metal oxides include, but are not limited to, vanadium dioxide and its derived vanadates or mixtures thereof.

3. The method for preparing the organic-inorganic composite cathode material according to claim 1, characterized in that, The organic carbonyl compound is 1,4,5,8-naphthalenetetracarboxylic anhydride (NTCDA), and the transition metal oxide is... The mixed solvent is a mixture of water and alcohol solvents.

4. The method for preparing the organic-inorganic composite cathode material according to claim 1, characterized in that, The mass ratio of organic carbonyl compounds to transition metal oxides is 0.01-0.03:

1.

5. The method for preparing the organic-inorganic composite cathode material according to claim 1, characterized in that, The solvothermal reaction temperature is 170-200℃, and the reaction time is 10-14h.

6. The method for preparing the organic-inorganic composite cathode material according to claim 1, characterized in that, During the stirring stage, water bath heating is carried out at a temperature of 120-150℃.

7. The organic-inorganic composite cathode material prepared by the method according to any one of claims 1-6, characterized in that, Organic carbonyl compounds are uniformly coated and / or partially intercalated in the layered structure of transition metal oxides. 8.The organic-inorganic composite cathode material of claim 7, characterized in that, Organic carbonyl compounds account for 1-3%.

9. The application of the organic-inorganic composite cathode material as described in claim 7, characterized in that, It is used in air-charged aqueous zinc-ion batteries.

10. The application of the organic-inorganic composite cathode material according to claim 9, characterized in that, The air-chargeable aqueous zinc-ion battery uses zinc or zinc-based materials as the negative electrode and aqueous zinc salt electrolyte.

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