Application of Zn3 (HHTP) 2 and NiCo-LDH nanoflower composite material in preparation of supercapacitor electrode and friction generator electrode

Abstract

This invention provides an application of Zn3(HHTP)2 and NiCo-LDH nanoflower composite material in the preparation of supercapacitor electrodes and triboelectric generator electrodes. NiCo-LDH nanoflowers provide abundant pseudocapacitive active sites, while Zn3(HHTP)2 enhances the overall conductivity and pore structure characteristics, thereby improving the specific capacitance, rate performance, and cycle stability of the supercapacitor. Simultaneously, this composite material is further combined with a PVDF dispersion system and drop-coated onto nickel foam to construct a mesh-like triboelectric generator positive electrode material. This material is then assembled with an Ecoflex negative electrode to achieve dual applications of the same composite material in energy storage and triboelectric power generation.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and energy harvesting materials technology, specifically relating to the application of a Zn3(HHTP)2 and NiCo-LDH nanoflower composite material in the preparation of supercapacitor electrodes and triboelectric generator electrodes. Background Technology

[0002] Existing supercapacitor electrode materials mainly include carbon materials, conductive polymers, metal oxides / hydroxides, and metal-organic framework-derived materials. Two-dimensional conductive MOF material Zn3(HHTP)2 is considered one of the more promising energy storage materials due to its regular channels, large specific surface area, and good electron transport capability; however, its structural stability in alkaline electrolytes and its specific capacitance level when used alone are still insufficient to fully meet the requirements of high-performance supercapacitors.

[0003] NiCo-LDH, as a typical bimetallic layered compound, possesses abundant redox reaction sites and a high theoretical capacity, but suffers from insufficient conductivity and limited utilization of active materials. In existing technologies, LDH is often composited with carbon materials, conductive polymers, or other two-dimensional materials to improve its electrochemical performance.

[0004] Triboelectric generators, as self-powered devices, have attracted attention in the fields of wearable electronics and environmental energy harvesting in recent years. However, their electrode materials still generally suffer from problems such as imperfect conductive networks, insufficient utilization of active components, and simple structural designs.

[0005] Most existing supercapacitor electrode solutions focus on improving the single energy storage function. Although they can improve the conductivity and electrochemical activity of electrode materials to some extent, their material systems and structural designs mainly serve the energy storage device itself and have not been further extended to the energy harvesting field, resulting in low functional integration. Furthermore, while existing triboelectric generator composite films mention that output performance can be improved by combining MOFs with polymers, their active material systems are mostly concentrated on simple MOF / polymer combinations, lacking synergistic design with pseudocapacitive active components such as NiCo-LDH. Moreover, they are usually not combined with a three-dimensional conductive framework structure, resulting in a relatively simple material utilization method and limited ability to expand the overall functionality of the device.

[0006] Furthermore, existing technologies mostly focus on energy storage devices or triboelectric generation devices, and there is no known technology that combines Zn3(HHTP)2 with NiCo-LDH in situ on the surface of a nickel foam substrate, and further expands its triboelectric generation application through polymer dispersion film formation, thereby achieving a single composite material system that serves as both a supercapacitor electrode and a triboelectric generation functional layer. Therefore, how to construct a multifunctional composite material system with both good electrochemical energy storage performance and triboelectric generation response capability, and realize its synergistic application in supercapacitors and triboelectric generators, remains a problem that needs further research in the current technology. Summary of the Invention

[0007] The main drawbacks of the existing technology are: firstly, the stability of a single Zn3(HHTP)2 material is limited in the electrolyte environment, and the active sites are not fully utilized when used as an electrode alone; secondly, although the single NiCo-LDH material has good pseudocapacitive performance, its conductivity is low, which affects the rate performance and cycle stability; thirdly, the supercapacitor electrode and the triboelectric generator electrode are usually designed separately, and the material system and preparation route are independent of each other, making it difficult to take into account both energy storage and mechanical energy harvesting functions.

[0008] To address the aforementioned shortcomings, the present invention aims to propose a method for preparing a Zn3(HHTP)2 / NiCo-LDH composite electrode based on a nickel foam substrate. This method utilizes NiCo-LDH nanoflowers to provide abundant pseudocapacitive active sites and leverages Zn3(HHTP)2 to enhance overall conductivity and pore structure characteristics, thereby improving the specific capacitance, rate performance, and cycle stability of the supercapacitor. Furthermore, this composite material is combined with a PVDF dispersion system and drop-coated onto nickel foam to construct a mesh-like triboelectric generator positive electrode material. This material is then assembled with an Ecoflex negative electrode to achieve dual applications of the same composite material in energy storage and triboelectric power generation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: Application of a Zn3(HHTP)2 and NiCo-LDH nanoflower composite material in the preparation of supercapacitor electrodes and triboelectric generator electrodes.

[0010] A method for preparing supercapacitor electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following steps: (1) Pre-cleaning of nickel foam: Place the nickel foam in dilute hydrochloric acid for ultrasonic cleaning, then clean it with ultrapure water and anhydrous ethanol in sequence, and finally dry it in a vacuum drying oven at 60 ℃ and take it out for use. (2) Preparation of NiCo-LDH / NF: Nickel nitrate hexahydrate, cobalt nitrate hexahydrate and CTAB were added to an ultrapure water / methanol mixed solution with a volume ratio of 1:5 and stirred evenly to form a pink precursor solution; it was transferred to a polytetrafluoroethylene-lined reactor, and cleaned nickel foam was added. The reaction was carried out at 180 °C for 24 h. After the reaction, the sample was taken out, cleaned and dried at 60 °C to obtain NiCo-LDH / NF; (3) Preparation of Zn3(HHTP)2@NiCo-LDH / NF: Weigh 30 mg HHTP and 30 mg zinc acetate dihydrate, add 15 mL DMF and 15 mL ultrapure water, sonicate for 30 min and then put into NiCo-LDH / NF, react at 85 ℃ for 12 h; take it out and rinse repeatedly with ultrapure water and acetone until there is no deposit, and dry at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH / NF supercapacitor electrode.

[0011] A method for preparing triboelectric generator electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following steps: 1) Preparation of NiCo-LDH nanoflower powder: Nickel nitrate hexahydrate, cobalt nitrate hexahydrate and CTAB were added to an ultrapure water / methanol mixed solution with a volume ratio of 1:5 and stirred evenly to form a pink precursor solution; it was transferred to a polytetrafluoroethylene-lined reactor and reacted at 180 °C for 24 h; after the reaction, the sample was taken out, washed and dried at 60 °C to obtain NiCo-LDH nanoflower powder; 2) Preparation of Zn3(HHTP)2@NiCo-LDH powder: Weigh 30 mg HHTP and 30 mg zinc acetate dihydrate, add 15 mL DMF and 15 mL ultrapure water, sonicate for 30 min, then add NiCo-LDH nanoflower powder, and react at 85 ℃ for 12 h; wash with distilled water, anhydrous ethanol and acetone by centrifugation in sequence, and dry at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH powder; 3) Preparation of network Zn3(HHTP)2@NiCo-LDH@PVDF / NF: Zn3(HHTP)2@NiCo-LDH powder was added to a PVDF / DMF mixed dispersion system with a mass ratio of 5%, sonicated for 5 h, and treated in a 70 ℃ water bath for 24 h to obtain a uniform colloidal solution; pre-cleaned and dried nickel foam was taken, and the colloidal solution was drop-coated onto the surface of the nickel foam and dried on a 60 ℃ heating stage; through multiple drop-coating-drying cycles, a uniformly dispersed network composite layer was formed on the surface of the nickel foam to obtain the network Zn3(HHTP)2@NiCo-LDH@PVDF / NF triboelectric generator electrode.

[0012] Furthermore, the supercapacitor test electrode was constructed: Zn3(HHTP)2@NiCo-LDH / NF was used as the working electrode, a platinum sheet as the counter electrode, Hg / HgO as the reference electrode, and 1 mol / L KOH as the electrolyte to form a three-electrode system. Its cyclic voltammetry, constant current charge-discharge and impedance performance were tested to evaluate its energy storage performance.

[0013] Furthermore, construct the triboelectric generator device: Take a 3×3 cm piece 2 A mesh-like Zn3(HHTP)2@NiCo-LDH@PVDF / NF is used as the positive electrode for friction, with conductive copper tape fixed to the back. Ecoflex silicone of the same size and about 2 mm thick is selected as the negative electrode for friction, with conductive copper tape also fixed to the back. The positive and negative electrodes are then fixed to a PMMA board, and polyurethane sponge supports are set at the four corners to obtain the triboelectric generator device.

[0014] Furthermore, through the above steps, this invention enables the application of the same composite material system in supercapacitor electrodes and triboelectric generator electrodes. Specifically, Zn3(HHTP)2@NiCo-LDH / NF is mainly used for energy storage testing, while the mesh-like Zn3(HHTP)2@NiCo-LDH@PVDF / NF is mainly used as the positive electrode material for triboelectric generators.

[0015] Furthermore, the conductive substrate can be replaced with carbon cloth, conductive fabric, stainless steel mesh, or other substrate materials with a three-dimensional conductive framework.

[0016] Furthermore, the binder in the dispersion system can be replaced with other polymer systems that can form a stable coating.

[0017] Furthermore, in addition to Ecoflex, other flexible polymer materials with strong triboelectric negative properties can also be selected as the negative electrode material for the triboelectric generator.

[0018] Furthermore, without changing the composite approach, the loading amount, number of drop coatings, substrate size, and device structure of Zn3(HHTP)2 and NiCo-LDH can all be adjusted according to actual needs.

[0019] The advantages of this invention are: (1) By synergistically combining Zn3(HHTP)2 with NiCo-LDH, the stability of the electrode structure is improved while taking into account both conductivity and pseudocapacitive activity, which is beneficial to improving the specific capacitance, rate performance and cycle stability of supercapacitors.

[0020] (2) Using nickel foam as a three-dimensional conductive substrate is beneficial to the uniform loading of active materials and rapid electron transport, while also helping electrolyte wetting and ion diffusion.

[0021] (3) Based on the preparation of energy storage electrodes, the composite material is further constructed as the positive electrode of the mesh triboelectric generator, realizing the extended application of the same material system in both energy storage and energy harvesting directions, which has the advantage of functional integration.

[0022] (4) The overall preparation route is clear, the raw materials and process conditions used are relatively conventional, and it is feasible to further scale up and apply it. Attached Figure Description

[0023] Figure 1 A photograph of the Zn3(HHTP)2@NiCo-LDH / NF composite material; Figure 2 XRD pattern of Zn3(HHTP)2@NiCo-LDH composite material; Figure 3 The image shows the FTIR spectrum of the Zn3(HHTP)2@NiCo-LDH composite material. Figure 4 The CV (a), EIS (b), and GCD (c) plots are for the Zn3(HHTP)2@NiCo-LDH / NF supercapacitor. Figure 5 The output voltage (a), current (b), and charge (c) of the Zn3(HHTP)2@NiCo-LDH / NF triboelectric generator are shown in the diagram. Figure 6 A diagram showing the operation of lighting 45 LED bulbs for a Zn3(HHTP)2@NiCo-LDH / NF triboelectric generator. Detailed Implementation

[0024] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are provided below for detailed description. Unless otherwise specified, the methods of the present invention are conventional methods in the art.

[0025] The materials used in the examples, such as nickel foam, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, CTAB, HHTP, and Ecoflex, are all commercially available products, making them easy to implement and reproduce. Example 1

[0026] A method for preparing supercapacitor electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following specific steps: (1) Pre-cleaned nickel foam: cut 1×5 cm 2 The foamed nickel was ultrasonically cleaned in 1 mol / L dilute hydrochloric acid for 20 min, then ultrasonically cleaned in ultrapure water and anhydrous ethanol for 5 min each, and repeated twice. Finally, it was dried in a vacuum drying oven at 60 ℃ for 12 h and then taken out for use. (2) Preparation of NiCo-LDH / NF: Weigh 1.5 mmol nickel nitrate hexahydrate, 1.0 mmol cobalt nitrate hexahydrate and 1 g CTAB respectively, add them to a mixed solution of ultrapure water / methanol with a volume ratio of 1:5 (12 mL ultrapure water and 60 mL methanol), stir evenly to form a pink precursor solution; transfer it to a polytetrafluoroethylene-lined reactor, add the pretreated nickel foam, and react at 180 °C for 24 h. After the reaction, take out the sample, wash it and dry it at 60 °C to obtain NiCo-LDH / NF; (3) Preparation of Zn3(HHTP)2@NiCo-LDH / NF: Weigh 30 mg HHTP and 30 mg zinc acetate dihydrate, add 15 mL DMF and 15 mL ultrapure water, sonicate for 30 min, then place in NiCo-LDH / NF, and react at 85 ℃ for 12 h; after removal, rinse repeatedly with ultrapure water and acetone until no deposits are found, and dry at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH / NF composite electrode (see Figure 1 ). Example 2

[0027] A method for preparing triboelectric generator electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following specific steps: (1) Preparation of NiCo-LDH nanoflower powder: 0.244 g of nickel nitrate hexahydrate, 0.163 g of cobalt nitrate hexahydrate, and 2 g of cetyltrimethylammonium bromide were weighed out, and 12 mL of deionized water and 60 mL of methanol were added and stirred until a uniform, transparent pink solution was obtained. Then, the solution was placed in a container with a polytetrafluoroethylene liner. After reacting in a precision forced-air drying oven at 180 °C for 24 h, the solution was allowed to cool naturally to room temperature. After the reaction was completed, a green precipitate was formed. The precipitate was washed three times each with deionized water and anhydrous ethanol by centrifugation, and then dried in a vacuum drying oven at 60 °C for 24 h to obtain NiCo-LDH nanoflower powder. (2) Preparation of Zn3(HHTP)2@NiCo-LDH powder: Weigh 30 mg of HHTP ligand (hexahydroxytriphenylene) (dissolved in DMF) and 30 mg of zinc acetate dihydrate (dissolved in water), and add them to a scintillation bottle; then add 15 mL of N,N-dimethylformamide (DMF) and 15 mL of deionized water to the scintillation bottle; sonicate in an ice bath for 30 min at a power of 90 W; then add 0.1 g of the pre-prepared NiCo-LDH nanoflower powder. Finally, place the mixed solution in a precision drying oven at 85 ℃ for 12 h, and remove it after natural cooling to room temperature; a dark blue substance is generated. Wash with distilled water, anhydrous ethanol and acetone by centrifugation, and dry in a vacuum drying oven at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH powder; (3) Preparation of network Zn3(HHTP)2@NiCo-LDH@PVDF / NF composite material: Zn3(HHTP)2@NiCo-LDH powder was weighed at mass fractions of 5%, 10%, 15%, and 20%, and a PVDF / DMF mixture with a mass ratio of 5% was used as the dispersion medium. The mixture was sonicated for 5 h and treated in a water bath at 70 ℃ for 24 h to obtain uniform colloidal solutions with different solid contents; four 3×3 cm pieces of pre-cleaned and dried Zn3(HHTP)2@NiCo-LDH@PVDF / NF composite material were taken. 2 Nickel foam was prepared by drop-coating colloidal solutions of different mass fractions onto the surface of nickel foam and drying them on a heating platform at 60 ℃. Through multiple drop-coating cycles (1 mL each time, 2 times) and drying cycles, a uniformly dispersed network composite layer was formed on the surface of the nickel foam, resulting in network Zn3(HHTP)2@NiCo-LDH@PVDF / NF composite materials with different ratios.

[0028] Application examples (1) Constructing supercapacitor test electrodes: Zn3(HHTP)2@NiCo-LDH / NF was used as the working electrode, platinum sheet as the counter electrode, Hg / HgO as the reference electrode, and 1 mol / L KOH solution as the electrolyte to construct a three-electrode system. Its cyclic voltammetry, constant current charge-discharge and impedance performance were tested to evaluate its energy storage performance. (2) Constructing a triboelectric generator device: Take a 3×3 cm piece 2 A mesh-like Zn3(HHTP)2@NiCo-LDH@PVDF / NF is used as the positive electrode for friction, with conductive copper tape fixed to the back. Ecoflex silicone of the same size and about 2 mm thick is selected as the negative electrode for friction, with conductive copper tape also fixed to the back. The positive and negative electrodes are then fixed to a PMMA board, and polyurethane sponge supports are set at the four corners to obtain the triboelectric generator device.

[0029] Through the above steps, this invention realizes the application of the same composite material system in supercapacitor electrodes and triboelectric generator electrodes. Specifically, Zn3(HHTP)2@NiCo-LDH / NF is mainly used for energy storage testing, while the mesh-like Zn3(HHTP)2@NiCo-LDH@PVDF / NF is mainly used as the positive electrode material for triboelectric generators.

[0030] Figure 4 The figures show the CV (a), EIS (b), and GCD (c) plots of the Zn3(HHTP)2@NiCo-LDH / NF supercapacitor. The Zn3(HHTP)2@NiCo-LDH / NF electrode is shown at 1 mA cm⁻¹. -2 The capacitor below is 1460 mF cm. -2 The composite electrode improves both the areal capacitance and the cycling stability of the single-conductive MOF, increasing the cycle stability from 60% for Zn3(HHTP)2 / NF to 81% for the composite electrode Zn3(HHTP)2@NiCo-LDH / NF after 1000 cycles. The assembled ASCII device exhibits excellent cycling stability at 1 mAcm⁻¹. -2 The surface capacitance is 375 mF cm. -2 The surface energy density is 133.33 μWh / cm². -2 The corresponding surface power density is 0.8 mW / cm². -2 This indicates that the device can maintain a high energy output even under low power output conditions, demonstrating that the composite of Zn3(HHTP)2 and NiCo-LDH can effectively improve the energy storage performance of the electrode material.

[0031] Figure 5 The output voltage (a), current (b), and charge (c) of the Zn3(HHTP)2@NiCo-LDH / NF triboelectric generator are shown. Under the conditions of device size of 30 mm × 30 mm, load pressure of 20 N, and frequency of 2 Hz, an open-circuit voltage of approximately 55 V, a current of 0.4 μA, and a charge transfer of approximately 20 nC can be obtained.

[0032] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. Application of a Zn3(HHTP)2 and NiCo-LDH nanoflower composite material in the preparation of supercapacitor electrodes and triboelectric generator electrodes.

2. The application according to claim 1, characterized in that, A method for preparing supercapacitor electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following steps: (1) Pre-cleaning of nickel foam: Place the nickel foam in dilute hydrochloric acid for ultrasonic cleaning, then clean it with ultrapure water and anhydrous ethanol in sequence, and finally dry it in a vacuum drying oven at 60 ℃ and take it out for use. (2) Preparation of NiCo-LDH / NF: Nickel nitrate hexahydrate, cobalt nitrate hexahydrate and CTAB were added to an ultrapure water / methanol mixed solution with a volume ratio of 1:5 and stirred evenly to form a pink precursor solution; it was transferred to a polytetrafluoroethylene-lined reactor, and cleaned nickel foam was added. The reaction was carried out at 180 °C for 24 h. After the reaction, the sample was taken out, cleaned and dried at 60 °C to obtain NiCo-LDH / NF; (3) Preparation of Zn3(HHTP)2@NiCo-LDH / NF: Weigh 30 mg HHTP and 30 mg zinc acetate dihydrate, add 15 mL DMF and 15 mL ultrapure water, sonicate for 30 min and then put into NiCo-LDH / NF, react at 85 ℃ for 12 h; take it out and rinse repeatedly with ultrapure water and acetone until there is no deposit, and dry at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH / NF supercapacitor electrode.

3. The application according to claim 1, characterized in that, A method for preparing triboelectric generator electrodes using Zn3(HHTP)2 and NiCo-LDH nanoflower composite materials includes the following steps: 1) Preparation of NiCo-LDH nanoflower powder: Nickel nitrate hexahydrate, cobalt nitrate hexahydrate and CTAB were added to an ultrapure water / methanol mixed solution with a volume ratio of 1:5 and stirred evenly to form a pink precursor solution; it was transferred to a polytetrafluoroethylene-lined reactor and reacted at 180 °C for 24 h; after the reaction, the sample was taken out, washed and dried at 60 °C to obtain NiCo-LDH nanoflower powder; 2) Preparation of Zn3(HHTP)2@NiCo-LDH powder: Weigh 30 mg HHTP and 30 mg zinc acetate dihydrate, add 15 mL DMF and 15 mL ultrapure water, sonicate for 30 min, then add NiCo-LDH nanoflower powder, and react at 85 ℃ for 12 h; wash with distilled water, anhydrous ethanol and acetone by centrifugation in sequence, and dry at 60 ℃ for 24 h to obtain Zn3(HHTP)2@NiCo-LDH powder; 3) Preparation of mesh Zn3(HHTP)2@NiCo-LDH@PVDF / NF: Zn3(HHTP)2@NiCo-LDH powder was added to a PVDF / DMF mixture with a mass ratio of 5%, sonicated for 5 h, and treated in a 70 ℃ water bath for 24 h to obtain a uniform colloidal solution; pre-cleaned and dried nickel foam was taken, and the colloidal solution was drop-coated onto the surface of the nickel foam and dried on a 60 ℃ heating stage; through multiple drop-coating-drying cycles, a uniformly dispersed mesh composite layer was formed on the surface of the nickel foam to obtain the mesh Zn3(HHTP)2@NiCo-LDH@PVDF / NF triboelectric generator electrode.

Images