A graphene pigment orange composite material and its preparation method and application

Abstract

The present invention discloses a graphene pigment orange composite material, its preparation method and application, and relates to the technical field of electrode materials. The graphene pigment orange composite material is a composite material with a sheet-like stacked structure obtained by synthesizing o-phenylenediamine, 1,4,5,8-naphthalenetetracarboxylic acid and graphene oxide through an in-situ condensation reflux method. The preparation method of the present invention is simple, low-cost and high-yield. The abundant C=N and C=O groups serve as redox active sites to realize Li + The reversible storage of graphene pigment orange improves the electrochemical specific capacity of the electrode material. The π conjugated system formed with graphene can effectively inhibit the dissolution of the electrode material and promote charge transfer, so that the graphene pigment orange composite material has an excellent long cycle life and good rate performance.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials, and in particular to a graphene pigment orange composite material and a preparation method and application thereof. Background Art

[0002] Energy storage is one of the most important topics of the 21st century. Over the past few years, energy storage has garnered worldwide attention. Lithium-ion batteries are currently the most promising energy storage devices, with output energy typically exceeding 90% of input energy. Since their introduction in the 1990s, lithium-ion batteries have been the primary power source for portable electronic devices. However, the development of lithium-ion batteries has not kept pace with the growing demand for energy. In particular, the energy storage capacity of lithium-ion batteries is insufficient to meet the needs of emerging electric vehicles and smart grids. Therefore, the energy storage capacity of lithium-ion batteries needs to be further improved, which requires increasing the specific capacity of electrode materials, particularly those on the positive electrode side.

[0003] The practical capacity of conventional inorganic intercalation electrodes is usually limited to Moreover, traditional inorganic cathode materials are non-renewable in nature, have complex preparation processes, are costly, and easily lead to resource depletion and environmental pollution, which seriously restricts the development of secondary batteries. Therefore, it is crucial to explore alternative electrode materials to meet these challenges.

[0004] Compared with inorganic electrode materials, organic electrode materials offer various advantages. For example, organic materials have a wide range of raw materials, and their synthetic raw materials typically come from biomass, petrochemicals, and other fields. These resources are relatively abundant and renewable. Compared with some scarce inorganic metal resources, the large-scale application of organic electrode materials is more sustainable. Organic materials generally have a low density, which makes organic electrode materials lighter, which is beneficial for improving the energy density and power density of batteries. At the same time, the molecular structure of organic electrode materials can be flexibly adjusted. By changing the chemical structure of organic molecules, the type of functional groups, and the connection method, the electrochemical properties of the materials, such as redox potential and capacity, can be precisely controlled. In the subsequent recycling and reuse process, because the chemical structure of organic materials is relatively simple, at the end of the battery life, the organic electrode materials can be separated from the battery through simple chemical treatment or pyrolysis methods, and then recycled and reused, reducing pollution to the environment and waste of resources. This shows that organic electrode materials have a good development prospect.

[0005] Pigment Orange is inexpensive to synthesize and has a simple synthesis method. More importantly, its abundant C=N and C=O groups and conjugated structure in its molecular structure ensure both high theoretical capacity and high electronic conductivity. These advantages indicate that Pigment Orange is an ideal organic cathode material and can be produced on a large scale. However, Pigment Orange exhibits a certain solubility in organic electrolytes, which has a certain impact on its cycling stability. Therefore, the use of Pigment Orange as an organic cathode material requires further improvement. Summary of the Invention

[0006] The invention discloses a graphene pigment orange composite material, a preparation method and an application thereof, in order to solve the problem of poor cycle stability when the existing pigment orange is used as an organic positive electrode material.

[0007] The technical solution adopted in the present invention is as follows:

[0008] One of the objects of the present invention is to provide a graphene pigment orange composite material, which is a composite material with a sheet-like stacked structure obtained by synthesizing o-phenylenediamine, 1,4,5,8-naphthalenetetracarboxylic acid and graphene oxide through an in-situ condensation reflux method.

[0009] A second object of the present invention is to provide a method for preparing a graphene pigment orange composite material, comprising the following steps:

[0010] (1) o-phenylenediamine and 1,4,5,8-naphthalenetetracarboxylic acid were added to an acetic acid solution, and then the graphene oxide dispersion was continuously added. The mixture was ultrasonicated at room temperature for 30-60 min to mix the materials evenly, and then condensed and refluxed to produce a large amount of orange-red solid.

[0011] (2) After the reaction is completed, stop the reaction and cool to room temperature. Then, centrifuge and wash the reaction mixture obtained in step 1 with acetic acid and deionized water for 3 to 5 times respectively. The solid product obtained is vacuum dried. Then, the dried product is Soxhlet extracted with anhydrous ethanol for 20 to 28 hours, and then vacuum dried at 80 to 100 ° C for 20 to 28 hours. The orange-red target product obtained is the graphene pigment orange composite material.

[0012] Furthermore, the mass ratio of o-phenylenediamine, 1,4,5,8-naphthalenetetracarboxylic acid and graphene oxide is 1:1.3-2:0.1-0.22.

[0013] Furthermore, in step (1), the reaction temperature of the condensation reflux reaction is 80-100° C., and the reaction time is 3-8 h.

[0014] Furthermore, in step (2), the process of Soxhlet extraction of the dried product with anhydrous ethanol is as follows: placing the dried product in a filter paper sleeve and placing it in a Soxhlet extractor; adding anhydrous ethanol to the solvent bottle of the Soxhlet extractor and heating it under reflux at 60-80°C; after 20-28 hours, removing the filter paper sleeve and collecting the sample by filtration with ethanol. The purpose of Soxhlet extraction of the washed product with anhydrous ethanol for 20-28 hours after vacuum drying is to fully remove impurities.

[0015] The third object of the present invention is to protect the application of the graphene pigment orange composite material as a positive electrode material for lithium-ion batteries.

[0016] A fourth object of the present invention is to provide a lithium-ion battery prepared using the graphene pigment orange composite material.

[0017] Preferably, the preparation process of the lithium-ion battery is as follows: using the graphene pigment orange composite material as the active material, mixing it with a binder and a conductive agent in an organic solvent, coating it on aluminum foil, vacuum drying it at 80-100°C for more than 12 hours, and cutting it to prepare a positive electrode sheet; using metallic lithium as the negative electrode, placing a diaphragm, adding an electrolyte, and assembling to form a lithium-ion battery.

[0018] The conductive agent, binder, and graphene pigment orange composite material have a mass ratio of 3:1:6. The conductive agent, binder, and graphene pigment orange composite material are mixed in an organic solvent and then ground into a slurry with a particle size of 5 to 10 μm. In the present invention, the 3:1:6 mass ratio of the conductive agent, binder, and graphene / pigment orange composite material ensures the loading of active material and effectively increases the conductivity of the material. The advantage of grinding to a particle size of 5 to 10 μm is that the active sites are fully exposed.

[0019] The conductive agent is Ketjen black; the binder is polyvinylidene fluoride; the diaphragm is a polypropylene diaphragm; the electrolyte is a lithium salt electrolyte, the electrolyte of the lithium salt electrolyte is lithium bis(trifluoromethanesulfonyl)imide, and the solvent of the lithium salt electrolyte is 1,3-dioxolane and propylene glycol methyl ether acetate.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] (1) The graphene pigment orange composite material provided by the present invention has abundant C=N and C=O groups as redox active sites to realize Li + The reversible storage of lithium ions can improve the electrochemical specific capacity of the electrode material. The π conjugated system formed with graphene can effectively inhibit the dissolution of the electrode material and promote charge transfer. Moreover, the sheet structure can increase the transmission rate of electrons and lithium ions, which is conducive to making full use of the active material to increase the battery capacity and reflect excellent rate performance.

[0022] (2) The graphene pigment orange composite material provided by the present invention can greatly increase its stability in organic electrolyte after pigment orange and graphene are loaded. The battery prepared by using the composite material has excellent cycle stability, high specific capacity and stable charge and discharge platform. -1 The capacity after 200 cycles is 250mAh.g -1 , and exhibits good low temperature performance.

[0023] (3) The preparation method of the graphene pigment orange composite material provided by the present invention is simple, the raw material cost is low, and it can be synthesized on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The synthetic route of the graphene pigment orange composite material of the present invention is shown in FIG.

[0025] Figure 2 This is a Fourier transform infrared spectrum of the graphene pigment orange composite material obtained in Example 1 of the present invention.

[0026] Figure 3 This is a scanned photo of the graphene pigment orange composite material obtained in Example 1 of the present invention.

[0027] Figure 4 The graphene pigment orange composite material obtained in Example 1 of the present invention is subjected to 50 mA.g -1 Constant current charge and discharge curve of room temperature lithium-ion battery under current density.

[0028] Figure 5 This is a rate cycling performance diagram of the graphene pigment orange composite material obtained in Example 1 of the present invention when applied to a room temperature lithium-ion battery.

[0029] Figure 6 The graphene pigment orange composite material obtained in Example 1 of the present invention is subjected to 2000 mA.g -1 Electrochemical cycling diagram of a room-temperature lithium-ion battery at different current densities.

[0030] Figure 7 The graphene pigment orange composite material obtained in Example 1 of the present invention is subjected to 200 mA.g -1 Electrochemical cycling diagram of lithium-ion batteries at different temperatures and current densities. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than for limiting the present invention.

[0032] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event of any conflict, the present specification shall take precedence.

[0033] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0034] In the following embodiments, the battery performance tests were performed using a Xinwei battery testing system and a Princeton electrochemical workstation. Low-temperature tests required placing the battery in a low-temperature test chamber at different temperatures.

[0035] Example 1

[0036] The present invention provides a graphene pigment orange composite material, such as Figure 1 As shown, the preparation process includes the following steps:

[0037] Step 1: Add 4.5-5.8g of o-phenylenediamine and 6-9g of 1,4,5,8-naphthalenetetracarboxylic acid to 200-300mL of acetic acid solution. Then, continuously add 50-80mL of a graphene oxide dispersion containing 0.6-0.96g of graphene oxide. Ultrasonicate the mixture at room temperature for 30-60 minutes to mix thoroughly. Stir and reflux at 60-100°C for 3-8 hours.

[0038] Step 2: After the reaction is completed, stop the reaction and cool to room temperature, then centrifuge and wash with acetic acid and deionized water for 3-5 times, and vacuum dry the obtained solid product. The obtained product is extracted with anhydrous ethanol for 20-28 hours, and then vacuum dried at 80-100°C for 20-28 hours to obtain an orange-red target product, which is a graphene pigment orange composite material. The Soxhlet extraction process is as follows: put the product into a filter paper sleeve and put it into a Soxhlet extractor; add anhydrous ethanol to the solvent bottle of the Soxhlet extractor and heat it to reflux at 60-80°C; after 20-28 hours, remove the filter paper sleeve and collect the sample by ethanol filtration. In this embodiment, the purpose of Soxhlet extraction of the washed product with anhydrous ethanol for 20-28 hours after vacuum drying is to fully remove impurities.

[0039] like Figure 2 As shown, the graphene pigment orange composite material prepared in this embodiment has a -1 、1450cm -1 and 1740cm -1 The characteristic peaks at correspond to CN, C=N and C=O bonds, respectively, which indicates that abundant CN, C=N and C=O bonds are formed in the material.

[0040] like Figure 3 As shown, it can be clearly seen that the graphene pigment orange composite material prepared in this embodiment is in a sheet-like stacked shape.

[0041] Example 2

[0042] This embodiment provides a lithium ion battery prepared using the graphene pigment orange composite material obtained in Example 1. The preparation process of the battery is as follows:

[0043] The graphene / pigment orange composite electrode material, Ketjen black and polyvinylidene fluoride (PVDF) obtained in Example 1 were mixed with N-methylpyrrolidone (NMP) solution in a mass ratio of 6:3:1, and ground into a well-dispersed slurry in an agate mortar. The particle size of the material in the slurry was 5 to 10 μm. The slurry was evenly coated on an aluminum foil current collector and dried in a vacuum oven at 90 to 110 ° C for 10 to 12 hours to prepare a working electrode. The working electrode was used as the positive electrode, the metal lithium sheet was used as the negative electrode, the polypropylene diaphragm was used as the diaphragm, and 1M lithium bis(trifluoromethanesulfonyl)imide was used as the electrolyte (configuration) to assemble a 2032 button cell. The test voltage range was 1.1V-3.6V relative to Li / Li + .

[0044] like Figure 4 As shown, the 2032 button battery prepared in this embodiment has a high capacitance at 2.24 V / 2.43 V (relative to Li / Li + ) and a pair of flat redox peaks appeared at the bottom, with a maximum specific capacity of 260 mAh.g -1 , after 200 cycles, the capacity retention rate is as high as 90%. It can be concluded that the battery has high capacity and excellent cycle stability.

[0045] like Figure 5 As shown, the 2032 button battery prepared in this embodiment has the following characteristics: -1 At current densities of 260, 225, 215, 205, 198 and 190 mAh.g -1 The high discharge capacity, when the current density gradually returned to the initial 50mA.g -1 When the discharge capacity is still able to return to 250mAh.g -1 , proving that the material not only has excellent rate performance, but also maintains excellent reversibility.

[0046] like Figure 6 As shown, the 2032 button battery prepared in this embodiment has a high -1At a current density of 1.5 GHz, the battery can cycle stably for 5,000 cycles with a capacity retention rate of 78%, demonstrating the excellent long-cycle performance of the graphene / pigment orange positive electrode.

[0047] like Figure 7 As shown, the 2032 button battery prepared in this embodiment can obtain 215, 180, 150 and 140 mAh.g at temperatures of 25, 0, -15 and -25 ° C, respectively. -1 The high discharge capacity proves that the material can exhibit high electrochemical performance under different temperature environments.

[0048] Finally, it should be noted that the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention.

[0049] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.

Claims

1. A graphene pigment orange composite material, characterized in that The graphene pigment orange composite material is a composite material with a sheet-like stacked structure obtained by synthesizing o-phenylenediamine, 1,4,5,8-naphthalenetetracarboxylic acid and graphene oxide through an in-situ condensation reflux method. The mass ratio of o-phenylenediamine, 1,4,5,8-naphthalenetetracarboxylic acid and graphene oxide is 1:1.3-2:0.1-0.

22. The reaction temperature of the condensation reflux reaction is 60-100°C, and the reaction time is 3-8 hours.

2. The method for preparing the graphene pigment orange composite material according to claim 1, wherein The following steps are involved: (1) o-phenylenediamine and 1,4,5,8-naphthalenetetracarboxylic acid were added to an acetic acid solution, and then the graphene oxide dispersion was continuously added. The mixture was ultrasonicated at room temperature for 30-60 min to mix the materials evenly, and then condensed and refluxed to produce a large amount of orange-red solid. (2) After the reaction is completed, stop the reaction and cool to room temperature. Then, centrifuge and wash the reaction mixture obtained in step 1 with acetic acid and deionized water for 3 to 5 times respectively. The solid product obtained is vacuum dried. Then, the dried product is Soxhlet extracted with anhydrous ethanol for 20 to 28 hours, and then vacuum dried at 80 to 100 ° C for 20 to 28 hours. The orange-red target product obtained is the graphene pigment orange composite material.

3. The preparation method according to claim 2, wherein In step (2), the process of extracting the dried product with anhydrous ethanol using Soxhlet extraction is as follows: placing the dried product in a filter paper sleeve and placing it in a Soxhlet extractor; adding anhydrous ethanol to the solvent bottle of the Soxhlet extractor and heating it under reflux at 60-80°C; after 20-28 hours, removing the filter paper sleeve and collecting the sample by filtration with ethanol.

4. Use of the graphene pigment orange composite material as claimed in claim 1 as a positive electrode material for lithium ion batteries.

5. A lithium-ion battery prepared using the graphene pigment orange composite material according to claim 1.

6. The lithium-ion battery according to claim 5, wherein The lithium-ion battery preparation process is as follows: using a graphene pigment orange composite material as an active material, mixing it with a binder and a conductive agent in an organic solvent, coating it on aluminum foil, vacuum drying it at 80-100°C for more than 12 hours, and cutting it to prepare a positive electrode sheet; using metallic lithium as a negative electrode, placing a separator, adding an electrolyte, and assembling it to form a lithium-ion battery.

7. The lithium-ion battery according to claim 6, wherein The mass ratio of the conductive agent, the binder and the graphene pigment orange composite material is 3:1:

6. The conductive agent, the binder and the graphene pigment orange composite material are mixed in an organic solvent and then ground into a slurry with a particle size of 5 to 10 μm.

8. The lithium-ion battery according to claim 6, wherein The conductive agent is Ketjen black; the binder is polyvinylidene fluoride; the diaphragm is a polypropylene diaphragm; the electrolyte is a lithium salt electrolyte, the electrolyte of the lithium salt electrolyte is lithium bis(trifluoromethanesulfonyl)imide, and the solvent of the lithium salt electrolyte is 1,3-dioxolane and propylene glycol methyl ether acetate.

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