Neuron-like structure negative electrode material and preparation method and application thereof

Abstract

The invention discloses a neuron-like structure negative electrode material and a preparation method and application thereof, graphdiyne oxide and a carbon oxide nanotube adopt a one-step hydrothermal self-assembly method, the process is simple, expensive equipment is not needed, the neuron-like structure negative electrode material is suitable for large-scale production, and through hydrogen bond assembly between the graphdiyne oxide and the carbon oxide nanotube, the neuron-like structure negative electrode material is obtained. A bionic structure with a three-dimensional interconnection network and multistage pores is formed, and the ion diffusion path and the electron transmission efficiency are remarkably optimized. The negative electrode material shows high specific capacity and long cycle stability under rapid charge and discharge conditions, can still maintain relatively high capacity in a low-temperature environment, and breaks through the performance bottleneck of a traditional carbon-based material under extreme conditions. The method is applied to energy storage devices including but not limited to high-power lithium ion / sodium ion batteries and supercapacitors, and is suitable for low-temperature / fast-charging scene requirements including but not limited to electric vehicles and aerospace.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemistry and new energy materials, and in particular to a neuron-like structure negative electrode material and a preparation method and application thereof. Background Art

[0002] With the surge in demand for electric vehicles, portable electronic devices and energy storage in extreme environments, the limitations of traditional lithium-ion battery negative electrode materials (such as graphite and silicon-based materials) have become increasingly prominent. Although graphite materials are stable, they have low theoretical capacity (372mAh / g), are prone to lithium precipitation during fast charging, causing safety hazards, and the ion diffusion rate drops sharply at low temperatures, resulting in serious capacity attenuation; although silicon-based materials have high capacity, the huge volume expansion during charging and discharging causes structural pulverization and a sharp drop in cycle life. Optimizing conductivity and ion transport by constructing carbon-based heterostructures (such as graphene / carbon nanotube composites) is an effective strategy, but traditional heterointerfaces mostly rely on physical stacking, have poor interface stability, and are prone to ion transport bottlenecks at extreme rates or low temperatures. The preparation of traditional heterostructures often requires complex processes such as high-temperature annealing and chemical vapor deposition, resulting in high costs and high energy consumption.

[0003] Two-dimensional carbon-based heterostructures have become a research hotspot to break through the above bottlenecks due to their unique interface coupling effects. As a new type of sp-sp² hybrid carbon material, oxidized graphyne has excellent charge transfer potential due to its rich surface functional groups and three-dimensional through-hole structure; and oxidized carbon tubes have significant advantages in building fast ion transport networks due to their one-dimensional hollow topological structure and edge active site density. However, existing research has mostly focused on the modification and optimization of single carbon materials, and lacks a systematic understanding of the synergistic mechanism of multidimensional carbon-based heterogeneous interfaces, especially the key technology of constructing bionic ion channels through non-covalent bonds has not yet made a breakthrough. Summary of the invention

[0004] In order to overcome the above problems existing in the prior art, the present invention proposes a neuron-like structure negative electrode material and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a neuron-like structure negative electrode material, including oxidized graphene and oxidized carbon nanotubes, wherein the oxidized graphene is obtained by oxidizing graphene, and the oxidized carbon nanotubes are obtained by nitric acid oxidation method, and the heterogeneous structure obtained by synthesizing the oxidized graphene and the oxidized carbon nanotubes by hydrothermal method is the negative electrode material.

[0006] In the above-mentioned neuron-like structure negative electrode material, the carbon nanotube has a diameter of 6-8nm.

[0007] A method for preparing a neuron-like structure negative electrode material specifically comprises the following steps: Step 1, preparation of graphyne: pyridine is added into a three-necked flask containing a copper sheet, and then hexynylbenzene is added thereto, and the mixture is heated to 110° C. and refluxed for 72 hours. The copper sheet on which graphyne is grown is ultrasonically treated in hydrochloric acid, and then filtered, washed, and dried to obtain a graphyne polymer; Step 2, preparation of oxidized graphene: placing the graphene polymer obtained in step 1 in a single-mouth bottle, adding a magnet, adding concentrated sulfuric acid dropwise under ice-water bath conditions, and then adding hydrogen peroxide dropwise, stirring for 5 minutes under ice-water bath, transferring it to room temperature and stirring for 1 hour, adding a large amount of deionized water after the reaction is completed to quench the reaction, and centrifuging and drying to obtain oxidized graphene; Step 3, preparation of oxidized carbon nanotubes: Place the multi-walled carbon nanotubes in a dry single-necked bottle equipped with a condenser and slowly add 9 M HNO 3 , the mixture was refluxed at 75°C for 24h, after which it was filtered, washed and dried to obtain oxidized carbon nanotubes; Step 4, preparation of oxidized graphyne / oxidized carbon nanotube heterogeneous material: the oxidized graphyne obtained in step 2 and the oxidized carbon nanotubes obtained in step 3 are placed in a single-mouth bottle equipped with a magnet in a mass ratio of 3:7 and deionized water is added. After ultrasonic dispersion for 5 minutes, the mixture is stirred and condensed under reflux at 80°C for 24 hours to allow them to fully contact to obtain a heterogeneous structure.

[0008] In the above-mentioned method for preparing a neuron-like structure negative electrode material, the ratio of pyridine to copper sheet in step 1 is 150 mL: 20 copper sheets with a size of 1 cm×5 cm.

[0009] In the above-mentioned method for preparing a neuron-like structure negative electrode material, the volume ratio of concentrated sulfuric acid to hydrogen peroxide in step 2 is 7:3.

[0010] An application of a neuron-like structure negative electrode material, such as the above-mentioned neuron-like structure negative electrode material or a neuron-like structure negative electrode material prepared by the above-mentioned method of preparing a neuron-like structure negative electrode material, is applied to energy storage devices including but not limited to high-power lithium-ion / sodium-ion batteries and supercapacitors, and is suitable for low-temperature / fast charging scenarios including but not limited to electric vehicles and aerospace.

[0011] The beneficial effect of the present invention is that the present invention designs a bionic neuron topological structure: oxidized graphyne and oxidized carbon tubes are directionally bonded through hydrogen bonds to form a three-dimensional bionic neural network structure, thereby optimizing the ion transmission path, reducing the tortuosity of ion diffusion, and increasing the lithium ion diffusion coefficient and the lithium ion diffusion rate under low temperature conditions.

[0012] The present invention innovatively utilizes the oxygen-containing functional groups on the surface of GDYO and OCNTs to achieve hydrogen bond-guided assembly through a one-step hydrothermal method, avoiding the damage to the material structure caused by high-temperature treatment, and constructing a three-dimensional heterogeneous structure using a low-energy and high-efficiency method.

[0013] The present invention utilizes the difference in work function between oxidized graphene and oxidized carbon nanotubes to construct a built-in electric field, thereby accelerating the migration and diffusion of lithium ions, so that the material has excellent fast charging performance.

[0014] The heterostructure of the present invention has excellent fast charging capability, which is attributed to the fast lithium ion migration of the neuron bionic structure.

[0015] The heterostructure of the present invention has extreme temperature adaptability: at a low temperature of -20°C, it can still maintain a relatively high capacity under high-rate charge and discharge, and at a high temperature of 50°C, it can maintain high stability cycles under high-rate charge and discharge, with almost no capacity attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a scanning electron microscope image of the heterostructure negative electrode material obtained in Example 1 of the present invention; Figure 2 is a transmission electron microscope image of a heterogeneous structure negative electrode material obtained in Example 1 of the present invention; Figure 3 This is an atomic force microscope image of the heterostructure negative electrode material obtained in Example 1 of the present invention; Figure 4 is a KPFM diagram of a heterostructure negative electrode material obtained in Example 1 of the present invention; Figure 5 is a CV curve diagram of the heterostructure negative electrode material of Example 1 of the present invention; Figure 6 is a CV curve diagram of the heterostructure negative electrode material at 1 mV / s of Example 1 of the present invention; Figure 7 is the lithium ion diffusion coefficient obtained by GITT test and calculation of the heterostructure negative electrode material in Example 1 of the present invention; Figure 8 This is a rate performance test of the heterogeneous structure negative electrode material of Example 1 of the present invention and the control example; Fig. 9 The cycle performance test at 2A / g of the heterogeneous structure negative electrode material of Example 1 of the present invention and the comparative example; Fig.10 This is a cycle performance test at 10 A / g of the heterostructure negative electrode material of Example 1 of the present invention and the comparative example. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0018] This embodiment discloses a neuron-like structure negative electrode material, which includes oxidized graphene and oxidized carbon nanotubes, the mass of oxidized graphene is 18 mg, the mass of oxidized carbon nanotubes is 42 mg, the diameter of the carbon nanotubes is 6-8 nm, the oxidized graphene is obtained by oxidizing graphene, and the oxidized carbon nanotubes are obtained by nitric acid oxidation method. The heterostructure synthesized by hydrothermal method of oxidized graphene and oxidized carbon nanotubes is the negative electrode material.

[0019] Graphdyne is a new type of carbon material suitable for the negative electrode of fast-charged batteries. However, it is difficult to construct heterostructures using Graphdyne due to the stability of Graphdyne sheets. Therefore, oxidizing Graphdyne so that the edges of Graphdyne contain highly active oxygen-containing groups is an effective method to construct heterostructures of Graphyne. Carbon nanotubes have long-range ordered channels to provide lithium ion shuttle migration and diffusion, and their intrinsic structure has high conductivity. Heterogeneous formation of the two is expected to produce high-quality lithium-ion battery fast-charge negative electrode materials.

[0020] A method for preparing a neuron-like structure negative electrode material comprises the following steps: Step 1, preparation of graphyne: first add pyridine into a three-necked flask containing a copper sheet, then add hexynylbenzene, heat to 110°C, reflux for 72 hours, place the copper sheet with graphyne grown in hydrochloric acid for ultrasonic treatment, filter, wash and dry to obtain a graphyne polymer.

[0021] Step 2, preparation of oxidized Graphene: oxidized Graphene is obtained by mild oxidation of Graphene. Graphene is placed in a single-mouth bottle, a magnet is added, concentrated sulfuric acid is added dropwise under ice-water bath conditions, and then hydrogen peroxide is added dropwise, stirred for 5 minutes under ice-water bath, and then transferred to room temperature and stirred for 1 hour. After the reaction is completed, a large amount of deionized water is added to quench the reaction, and oxidized Graphene is obtained by centrifugal filtration and freeze-drying.

[0022] Step 3, preparation of oxidized carbon nanotubes: Place the multi-walled carbon nanotubes in a dry 50 mL single-mouth bottle equipped with a condenser, and slowly add 9 M HNO 3 The mixture was refluxed at 75°C for 24 hours, and then filtered, washed and dried to obtain oxidized carbon nanotubes.

[0023] Step 4, preparation of oxidized graphyne / oxidized carbon nanotube heterogeneous materials: the obtained oxidized graphyne and oxidized carbon tubes are placed in a single-mouth bottle equipped with a magnet in a mass ratio of 3:7 and deionized water is added. After ultrasonic dispersion for 5 minutes, the mixture is stirred, condensed and refluxed at 80°C for 24 hours to allow them to fully contact to obtain a heterogeneous structure.

[0024] In this embodiment, the ratio of pyridine to copper sheets in step 1 is 150 mL: 20 copper sheets of 1 cm×5 cm in size. The volume ratio of concentrated sulfuric acid to hydrogen peroxide in step 2 is 7:3. Example

[0025] Under argon protection, 100 mg of hexaynylbenzene was added to 10 pieces of 1 cm × 5 cm copper sheets, 150 mL of pyridine was added, and the reaction was carried out at 110 ° C for 72 h to obtain a copper sheet with graphyne. The copper sheet was rinsed with deionized water, and then added to 200 mL of 3M HCl solution for ultrasonication to separate the graphyne from the copper sheet, and then filtered, washed and dried to obtain graphyne.

[0026] Add a magnet and 100 mg of Graphene to a single-mouth bottle under ice-water bath conditions, add 7 mL of concentrated sulfuric acid under slow stirring conditions and gradually increase the stirring speed until all are added, add 3 mL of hydrogen peroxide dropwise, stir in an ice-water bath for 5 min after all are added, then transfer the single-mouth bottle to room temperature, stir at room temperature for 60 min, add 400 mL of deionized water to quench the reaction. Centrifuge the resulting mixture, remove the lower layer of solid after centrifugation, add deionized water and continue centrifugation until the pH test paper test solution shows neutral, and freeze-dry it to obtain 40 mg of Graphene oxide.

[0027] 80 mL of 9 M nitric acid was added to a single-mouth bottle, and 500 mg of carbon nanotubes were added. The mixture was stirred at 80° C. for 24 h, and then filtered, washed, and dried to obtain oxidized carbon nanotubes.

[0028] 42 mg of oxidized carbon nanotubes and 18 mg of oxidized graphene were added to a single-necked bottle, a stirring bar was added, and the mixture was stirred at 60° C. for 12 h to obtain a heterostructure material. Example

[0029] Under argon protection, 100 mg of hexaynylbenzene was added to 10 pieces of 1 cm × 5 cm copper sheets, 150 mL of pyridine was added, and the reaction was carried out at 110 ° C for 72 h to obtain a copper sheet with graphyne. The copper sheet was rinsed with deionized water, and then added to 200 mL of 3M HCl solution for ultrasonication to separate the graphyne from the copper sheet, and then filtered, washed and dried to obtain graphyne.

[0030] Add a magnet and 100 mg of Graphene to a single-mouth bottle under ice-water bath conditions, add 7 mL of concentrated sulfuric acid under slow stirring conditions and gradually increase the stirring speed until all are added, add 3 mL of hydrogen peroxide dropwise, stir in an ice-water bath for 5 min after all are added, then transfer the single-mouth bottle to room temperature, stir at room temperature for 60 min, add 400 mL of deionized water to quench the reaction. Centrifuge the resulting mixture, remove the lower layer of solid after centrifugation, add deionized water and continue centrifugation until the pH test paper test solution shows neutral, and freeze-dry it to obtain 40 mg of Graphene oxide.

[0031] 42 mg of carbon nanotubes and 18 mg of oxidized graphene were added into a single-mouth bottle, a stirring bar was added, and the mixture was stirred at 60° C. for 12 h to obtain a heterostructure material.

[0032] The electrical performance test method of the above-mentioned Example 1 and the comparative example is as follows: the obtained electrode material is placed on a copper foil to form a negative electrode sheet, and assembled with a metal lithium sheet into a button battery, and the electrolyte is 1 mol / L LiPF 6 Dissolved in DMC to test battery rate, cycle and other electrochemical properties.

[0033] Figure 1 This is a scanning electron microscope image of the oxidized Graphene / oxidized carbon nanotube carbon heterostructure negative electrode material obtained in Example 1 of the present invention. Figure 1 It can be observed that the GO / CO carbon nanotube carbon heterostructure presents a neuron-like structure, with the GDYO layer structure as the "neuron cell body", providing abundant active sites and ion storage space; and OCNTs as the "axon" extending to form a continuous conductive pathway.

[0034] Figure 2 This is a transmission electron microscope image of the oxidized Graphene / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention. A heterostructure similar to neurons can also be observed.

[0035] Figure 3 This is an atomic force microscope image of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material obtained in Example 1 of the present invention. From the image, it can be observed that the heterostructure has a certain height difference, and the carbon tubes therein radiate in all directions like star rays.

[0036] Figure 4 The KPFM diagram of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material obtained in Example 1 of the present invention is used to characterize that the oxidized graphyne and oxidized carbon nanotubes with different work functions constitute an interfacial built-in electric field. Under the action of the built-in electric field, the heterostructure has ultra-fast lithium ion diffusion dynamics.

[0037] Figure 5This is a CV curve diagram of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material obtained in Example 1 of the present invention. The b value is obtained by calculating and fitting at different scanning speeds to indicate the kinetic characteristics of the battery. The results show that the b value is close to 1, indicating that the lithium ion diffusion behavior of the material is dominated by the fast pseudocapacitive behavior on the surface, and therefore has excellent rate performance.

[0038] Figure 6 The CV curve at 1 mV / s of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention is used to calculate the pseudocapacitance ratio at a scan rate of 1 mV / s. The results show that the pseudocapacitance ratio is 73%.

[0039] Figure 7 The lithium ion diffusion coefficient obtained by GITT test and calculation of the oxidized Graphene / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention is 10 -8 to 10 -9 This shows that its lithium ion diffusion behavior is excellent and it has good fast charging performance.

[0040] Figure 8 The rate performance of the oxidized graphene / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention and the control example was tested. The results showed that the capacities of the two materials were similar at 0.1 A / g, but at current densities of 2 A / g and above, the gap between the two was large. The heterostructure had excellent rate performance and could maintain a relatively high capacity even at a high current density of 10 A / g.

[0041] Fig. 9 The cycle performance test of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention and the comparative example at 2A / g showed that its capacity was much higher than that of the comparative example.

[0042] Fig.10 The cycle performance test at 10 A / g of the oxidized graphyne / oxidized carbon nanotube carbon heterostructure negative electrode material prepared in Example 1 of the present invention and the comparative example showed that the capacity was much higher than that of the comparative example.

[0043] The material of the present invention is assembled through hydrogen bonds between oxidized Graphene and oxidized carbon tubes to form a bionic structure with a three-dimensional interconnected network and multi-level pores, which significantly optimizes the ion diffusion path and electron transmission efficiency. The negative electrode material exhibits high specific capacity and long cycle stability under fast charge and discharge conditions, and can still maintain a high capacity under low temperature conditions, breaking through the performance bottleneck of traditional carbon-based materials under extreme conditions. Among them, (1) the oxygen-containing functional groups on the surface of GDYO are used to form a strong hydrogen bond network with the hydroxyl / carboxyl groups of OCNTs to construct a highly stable heterogeneous interface; (2) the neuron-like topological structure realizes dual high-speed transmission of ions / electrons through multi-scale pores (micropore-mesopore synergy) and a continuous conductive skeleton; (3) the material is prepared by a one-step hydrothermal self-assembly method, which is simple in process and does not require expensive equipment, and is suitable for large-scale production. The invention is suitable for energy storage devices such as high-power lithium-ion / sodium-ion batteries and supercapacitors, especially for low-temperature / fast charging scenarios such as electric vehicles and aerospace, and has important commercial value.

[0044] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A neuron-like structure negative electrode material, characterized in that: The invention comprises oxidized graphene and oxidized carbon nanotubes. The oxidized graphene is obtained by oxidizing graphene, and the oxidized carbon nanotubes are obtained by nitric acid oxidation. The heterogeneous structure obtained by synthesizing the oxidized graphene and the oxidized carbon nanotubes by hydrothermal method is the negative electrode material.

2. The neuron-like structure negative electrode material according to claim 1, characterized in that: The carbon nanotube has a diameter of 6-8 nm.

3. A method for preparing a neuron-like structure negative electrode material, characterized in that: The specific steps include: Step 1, preparation of graphyne: pyridine is added into a three-necked flask containing a copper sheet, and then hexynylbenzene is added thereto, and the mixture is heated to 110° C. and refluxed for 72 hours. The copper sheet on which graphyne is grown is ultrasonically treated in hydrochloric acid, and then filtered, washed, and dried to obtain a graphyne polymer; Step 2, preparation of oxidized graphene: placing the graphene polymer obtained in step 1 in a single-mouth bottle, adding a magnet, adding concentrated sulfuric acid dropwise under ice-water bath conditions, and then adding hydrogen peroxide dropwise, stirring for 5 minutes under ice-water bath, transferring it to room temperature and stirring for 1 hour, adding a large amount of deionized water after the reaction is completed to quench the reaction, and centrifuging and drying to obtain oxidized graphene; Step 3, preparation of oxidized carbon nanotubes: multi-walled carbon nanotubes are placed in a dry single-mouth bottle equipped with a condenser, 9M HNO3 is slowly added, and the mixture is refluxed at 75°C for 24h, and then filtered, washed and dried to obtain oxidized carbon nanotubes; Step 4, preparation of oxidized graphyne / oxidized carbon nanotube heterogeneous material: the oxidized graphyne obtained in step 2 and the oxidized carbon nanotubes obtained in step 3 are placed in a single-mouth bottle equipped with a magnet in a mass ratio of 3:7 and deionized water is added. After ultrasonic dispersion for 5 minutes, the mixture is stirred and condensed under reflux at 80°C for 24 hours to allow them to fully contact to obtain a heterogeneous structure.

4. The method for preparing a neuron-like structure negative electrode material according to claim 3, characterized in that: In the step 1, the ratio of pyridine to copper sheets is 150 mL: 20 copper sheets with a size of 1 cm×5 cm.

5. The method for preparing a neuron-like structure negative electrode material according to claim 3, characterized in that: The volume ratio of concentrated sulfuric acid to hydrogen peroxide in step 2 is 7:

3.

6. An application of a neuron-like structure negative electrode material, characterized in that: The neuron-like structure negative electrode material as described in any one of claims 1-2 or the neuron-like structure negative electrode material prepared by the preparation method of the neuron-like structure negative electrode material as described in any one of claims 3-5 is applied to energy storage devices including but not limited to high-power lithium-ion / sodium-ion batteries and supercapacitors, and is suitable for low-temperature / fast charging scenarios including but not limited to electric vehicles and aerospace.

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