Graphite@polyaniline composite material, and preparation method and application thereof

Abstract

The application belongs to the technical field of aluminum batteries, and particularly relates to a graphite@polyaniline composite material and a preparation method and application thereof. In-situ growth of polyaniline is utilized to expand the interlayer spacing of graphite nanolayers, which is beneficial to embedding / detaching reactions in the reaction process of aluminum-graphite batteries, and the actual specific capacity of the aluminum-graphite batteries is improved. The process is simple, the cost is low, the aluminum ion secondary battery with high stability and high capacity can be obtained, and the application is green and environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of aluminum battery technology, specifically a graphite@polyaniline composite material, its preparation method, and its application. Background Technology

[0002] In its early stages, aluminum batteries faced challenges such as electrode corrosion, low discharge voltage, and poor cycle performance, resulting in slow development. It wasn't until 2015 that Professor Hongjie Dai of Stanford University reported an aluminum battery based on an ILE electrolyte, a metallic aluminum anode, and a pyrolytic graphite cathode in Nature. Around the same time, the inventor's team also reported this type of aluminum-graphite battery. This type of battery operates at approximately 2.0V and has a cathode specific capacity of approximately 70 mAh g⁻¹. -1 It exhibits almost no capacity decay after 7500 stable cycles. Its working mechanism involves the formation of aluminum complex ions (AlCl4) at the positive electrode during charge and discharge. - Intercalation / deintercalation between graphite layers, while Al occurs in the negative electrode. 3+ Deposition and dissolution. Although carbon materials exhibit good cycling stability, the active ions AlCl4 in the ionic liquid electrolyte used result in [the following]. - The relatively large size (0.528 nm) of AlCl4 in the graphite cathode leads to... - The reversible capacity is difficult to improve, which limits the capacity of intercalation / deintercalation aluminum-carbon batteries, with a discharge specific capacity of around 70 mAh g. -1 about. Summary of the Invention

[0003] To address the problems existing in the prior art, the main objective of this invention is to propose a graphite@polyaniline composite material, its preparation method and application, as well as the application of the graphite@polyaniline composite material as a cathode material for aluminum-ion batteries. The invention innovatively uses an in-situ growth method of polyaniline to cause aniline units to polymerize and grow in situ between graphite layers, thereby increasing the spacing between graphite layers and improving the actual specific capacity of aluminum-graphite batteries.

[0004] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0005] A method for preparing a graphite@polyaniline composite material includes the following steps:

[0006] S1. Mix aniline monomer and graphite powder to obtain a mixture;

[0007] S2. Add an initiator to the mixture to initiate the polymerization reaction and generate polyaniline between the graphite layers, thereby increasing the interlayer spacing of the graphite.

[0008] S3. The polymerized product is placed in a container filled with anhydrous ethanol for ultrasonic cleaning to remove impurities and then dried to obtain graphite@polyaniline composite material.

[0009] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S1, graphite powder is ultrasonically placed under acidic solution conditions, and then aniline monomer is added and magnetically stirred to obtain a mixture.

[0010] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S1, the mass ratio of graphite powder to aniline monomer is 5:(1~1.5).

[0011] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S1, the acidic solution refers to a solution with a pH value ≤ 2, and the pH value is controlled by hydrochloric acid or valine.

[0012] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S1, the ultrasonic time is 10-30 min and the magnetic stirring time is 12-15 h.

[0013] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S2, the initiator is an ammonium persulfate solution with a concentration of 0.03-0.05 g / mL.

[0014] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S2, the polymerization reaction time is more than 20 hours.

[0015] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S2, the liquid-solid ratio of the initiator to the aniline monomer is (2-3) mL:(0.1-0.2) g.

[0016] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, in step S3, ultrasonic cleaning is performed for ≥20 min.

[0017] In a preferred embodiment of the preparation method of graphite@polyaniline composite material according to the present invention, the drying temperature in step S3 is 50-200°C.

[0018] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0019] A graphite@polyaniline composite material is prepared using the above-described method for preparing graphite@polyaniline composite materials. The graphite interlayer spacing of the graphite@polyaniline composite material is 0.3–0.4 nm, and the specific surface area of ​​the composite material is 250–550 m². 2 / g.

[0020] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0021] An aluminum battery positive electrode is obtained by uniformly dispersing the above-mentioned graphite@polyaniline composite material, conductive additives and binders in a solvent, coating it on a conductive current collector, and vacuum drying it under conditions of 60-100°C and a vacuum pressure of 1-100Pa.

[0022] An aluminum battery is obtained by separating the positive and negative electrodes of the above-mentioned aluminum battery with a separator, injecting electrolyte, and assembling to obtain an aluminum battery with graphite@polyaniline composite material as the positive electrode.

[0023] In a preferred embodiment of the aluminum battery described in this invention, the discharge and charge voltages of the aluminum battery are 0.3–2.3V and 0.3–2.3V, respectively, and the current density is 0.1–1.0Ag. -1 Specific capacity is 40-120 mA hg -1 The number of reversible cycles can reach 10,000.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention proposes a graphite@polyaniline composite material, its preparation method, and its applications. Utilizing the in-situ growth of polyaniline, the interlayer spacing of graphite nanolayers is increased, facilitating the intercalation / deintercalation reactions during the aluminum-graphite battery reaction process and improving the actual specific capacity of the aluminum-graphite battery. The process is simple, low-cost, and can yield highly stable, high-capacity aluminum-ion secondary batteries that are environmentally friendly. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the preparation method of the graphite@polyaniline composite material of the present invention;

[0028] Figure 2 This is a morphology diagram of the graphite@polyaniline composite material prepared in Example 1 of the present invention.

[0029] Figure 3 The charge-discharge curves of the aluminum-ion secondary battery in Example 2 of this invention are shown.

[0030] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention proposes a graphite@polyaniline composite material, its preparation method, and its application. In order to improve the problems mentioned in the background art, it is necessary to expand the nano-layer spacing of graphite to improve the actual specific capacity of aluminum-graphite batteries. This invention innovatively uses the in-situ growth method of polyaniline to cause aniline units to polymerize and grow in situ between graphite layers, thereby expanding the graphite layer spacing. This is a very good way to improve the graphite layer spacing and can improve the specific capacity of aluminum-graphite batteries.

[0033] According to one aspect of the present invention, the present invention provides the following technical solution:

[0034] like Figure 1 As shown, a method for preparing a graphite@polyaniline composite material includes the following steps:

[0035] S1. Mix aniline monomer and graphite powder to obtain a mixture, so that the aniline monomer can be fully impregnated into the graphite carbon layer;

[0036] S2. Add an initiator to the mixture to initiate the polymerization reaction and generate polyaniline between the graphite layers, thereby increasing the interlayer spacing of the graphite.

[0037] S3. The polymerized product is placed in a container filled with anhydrous ethanol for ultrasonic cleaning to remove impurities and then dried to obtain graphite@polyaniline composite material.

[0038] This invention innovatively uses the in-situ growth method of polyaniline to polymerize and grow aniline units in situ between graphite layers, thereby increasing the spacing between graphite layers.

[0039] Preferably, in step S1, graphite powder is placed in an acidic solution and sonicated, and then aniline monomer is added and magnetically stirred to obtain a mixture; the mass ratio of graphite powder to aniline monomer is 5:(1-1.5), the acidic solution refers to a solution with a pH value ≤2, and the pH value is controlled by hydrochloric acid or valine; the sonication time is 10-30 min, and the magnetic stirring time is 12-15 h.

[0040] Preferably, in step S2, the initiator is an ammonium persulfate solution with a concentration of 0.03-0.05 g / mL; the polymerization reaction time is more than 20 h; and the liquid-solid ratio of the initiator to the aniline monomer is (2-3) mL:(0.1-0.2) g.

[0041] Preferably, in step S3, ultrasonic cleaning lasts for ≥20 minutes; the drying temperature is 50–200°C.

[0042] According to another aspect of the present invention, the present invention provides the following technical solution:

[0043] A graphite@polyaniline composite material is prepared using the above-described method for preparing graphite@polyaniline composite materials. The graphite interlayer spacing of the graphite@polyaniline composite material is 0.3–0.4 nm, and the specific surface area of ​​the composite material is 250–550 m². 2 / g.

[0044] According to another aspect of the present invention, the present invention provides the following technical solution:

[0045] An aluminum battery positive electrode is obtained by uniformly dispersing the above-mentioned graphite@polyaniline composite material, conductive additives and binders in a solvent, coating it on a conductive current collector, and vacuum drying it under conditions of 60-100°C and a vacuum pressure of 1-100Pa.

[0046] An aluminum battery is provided, comprising separating the positive and negative electrodes of the aforementioned aluminum battery with a separator, injecting an electrolyte, and assembling to obtain an aluminum battery with a graphite@polyaniline composite material as the positive electrode; the discharge and charging voltages of the aluminum battery are 0.3–2.3V and 0.3–2.3V, respectively, and the current density is 0.1–1.0Ag. -1 Specific capacity is 40-120 mA hg -1 The number of reversible cycles can reach 10,000.

[0047] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0048] Example 1

[0049] A method for preparing a graphite@polyaniline composite material includes the following steps:

[0050] S1. Aniline monomer and graphite powder are mixed to obtain a mixture, allowing the aniline monomer to fully impregnate into the graphite carbon layer; the graphite powder is placed in an acidic solution and ultrasonicated, then the aniline monomer is added and magnetically stirred to obtain a mixture; the mass ratio of graphite powder to aniline monomer is 5:1.5, the acidic solution refers to a solution with a pH value ≤2, and valine is used to control the pH value; the ultrasonic time is 10 min, and the magnetic stirring time is 12 h;

[0051] S2. Add an initiator to the mixture to initiate the polymerization reaction and generate polyaniline between the graphite layers, thereby increasing the interlayer spacing of the graphite. The initiator is an ammonium persulfate solution with a concentration of 0.04 g / mL. The polymerization reaction time is 20 h. The liquid-solid ratio of the amount of initiator added to the aniline monomer is 2 mL: 0.1 g.

[0052] S3. The polymerized product is placed in a container filled with anhydrous ethanol for ultrasonic cleaning to remove impurities and then dried. The ultrasonic cleaning is performed for 60 minutes. The drying temperature is 60℃ to obtain graphite@polyaniline composite material.

[0053] The morphology of the graphite@polyaniline composite material prepared in this embodiment is shown in the figure below. Figure 2 As shown, the graphite interlayer spacing of the graphite@polyaniline composite material is 0.4 nm, and the specific surface area of ​​the composite material is 550 m². 2 / g. The graphite@polyaniline composite material, conductive additives, and binders prepared in this embodiment are uniformly dispersed in a solvent, coated onto a conductive current collector, and vacuum dried at 60°C and a vacuum pressure of 100Pa to obtain the positive electrode of an aluminum battery. The above-mentioned positive and negative electrodes of the aluminum battery are separated by a separator, and an electrolyte is injected to assemble an aluminum battery with graphite@polyaniline composite material as the positive electrode.

[0054] Example 2

[0055] A method for preparing a graphite@polyaniline composite material includes the following steps:

[0056] S1. Aniline monomer and graphite powder are mixed to obtain a mixture, allowing the aniline monomer to fully impregnate into the graphite carbon layer; the graphite powder is placed in an acidic solution and ultrasonicated, then the aniline monomer is added and magnetically stirred to obtain a mixture; the mass ratio of graphite powder to aniline monomer is 5:1.25, the acidic solution refers to a solution with a pH value ≤2, and valine is used to control the pH value; the ultrasonic time is 20 min, and the magnetic stirring time is 12 h;

[0057] S2. Add an initiator to the mixture to initiate the polymerization reaction and generate polyaniline between the graphite layers, thereby increasing the interlayer spacing of the graphite. The initiator is an ammonium persulfate solution with a concentration of 0.03 g / mL. The polymerization reaction time is 30 h. The liquid-solid ratio of the amount of initiator added to the aniline monomer is 3 mL: 0.2 g.

[0058] S3. The polymerized product was placed in a container filled with anhydrous ethanol and ultrasonically cleaned to remove impurities. After drying, the product was ultrasonically cleaned for 60 minutes. The drying temperature was 60℃, yielding a graphite@polyaniline composite material with a graphite interlayer spacing of 0.35 nm and a specific surface area of ​​350 m². 2 / g.

[0059] The graphite@polyaniline composite material, conductive additives, and binders prepared in this embodiment were uniformly dispersed in a solvent, coated onto a conductive current collector, and vacuum dried at 70°C and 60 Pa to obtain the positive electrode of an aluminum battery. The positive and negative electrodes of the aluminum battery were separated by a separator, and an electrolyte was injected to assemble an aluminum battery with the graphite@polyaniline composite material as the positive electrode. The assembled battery was tested at 0.2 Ag. -1 Constant current charging and discharging were performed at a current density, and the charge-discharge curves are shown below. Figure 3 As shown. By Figure 3 It is evident that the graphite@polyaniline composite material expanded by in-situ polymerization, used as the positive electrode in an aluminum battery, achieves a current density of 50 mAg. -1 Under these conditions, the specific capacity of the second to fourth cycles was all around 120mAh g. -1 The above performance is quite outstanding.

[0060] Example 3

[0061] A method for preparing a graphite@polyaniline composite material includes the following steps:

[0062] S1. Aniline monomer and graphite powder are mixed to obtain a mixture, allowing the aniline monomer to fully impregnate into the graphite carbon layer; the graphite powder is placed in an acidic solution and ultrasonicated, then the aniline monomer is added and magnetically stirred to obtain a mixture; the mass ratio of graphite powder to aniline monomer is 5:1, the acidic solution refers to a solution with a pH value ≤ 2, and hydrochloric acid is used to control the pH value; the ultrasonic time is 30 min, and the magnetic stirring time is 12 h;

[0063] S2. Add an initiator to the mixture to initiate the polymerization reaction and generate polyaniline between the graphite layers, thereby increasing the interlayer spacing of the graphite; the initiator is an ammonium persulfate solution with a concentration of 0.05 g / mL; the polymerization reaction time is 20 h; the liquid-solid ratio of the amount of initiator added to the aniline monomer is 2 mL: 0.1 g.

[0064] S3. The polymerized product was placed in a container filled with anhydrous ethanol and ultrasonically cleaned to remove impurities. After drying, it was ultrasonically cleaned for 50 minutes. The drying temperature was 100℃ to obtain a graphite@polyaniline composite material with a graphite interlayer spacing of 0.33 nm and a specific surface area of ​​250 m². 2 / g.

[0065] The graphite@polyaniline composite material, conductive additives, and binders prepared in this embodiment are uniformly dispersed in a solvent, coated onto a conductive current collector, and vacuum dried at 80°C and a vacuum pressure of 50Pa to obtain the positive electrode of an aluminum battery. The above-mentioned positive and negative electrodes of the aluminum battery are separated by a separator, and an electrolyte is injected to assemble an aluminum battery with graphite@polyaniline composite material as the positive electrode.

[0066] As can be seen from the above embodiments, this invention utilizes the in-situ growth of polyaniline to increase the spacing between graphite nanolayers, which facilitates the intercalation / deintercalation reactions during the aluminum-graphite battery reaction process, thereby improving the actual specific capacity of the aluminum-graphite battery. The process is simple, low-cost, and can produce highly stable, high-capacity aluminum-ion secondary batteries that are environmentally friendly.

[0067] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An aluminum battery, characterized in that, An aluminum battery with a graphite@polyaniline composite material as the positive electrode was assembled by separating the positive and negative electrodes with a membrane and injecting electrolyte. The aluminum battery with the graphite@polyaniline composite material as the positive electrode was tested at a current density of 50 mA g. -1 Under these conditions, the specific capacity of the second to fourth cycles is all around 120 mA hg. -1 The aluminum battery can achieve a reversible cycle count of up to 10,000 cycles. The graphite@polyaniline composite material, conductive additives and binders were uniformly dispersed in a solvent, coated onto a conductive current collector, and vacuum dried at 70°C and 60Pa to obtain the positive electrode of an aluminum battery. The preparation method of graphite@polyaniline composite material includes the following steps: S1. Aniline monomer and graphite powder are mixed to obtain a mixture, allowing the aniline monomer to fully impregnate into the graphite carbon layer; the graphite powder is placed in an acidic solution and ultrasonicated, then the aniline monomer is added and magnetically stirred to obtain a mixture; the mass ratio of graphite powder to aniline monomer is 5:1.25, the acidic solution refers to a solution with a pH value ≤2, and valine is used to control the pH value; the ultrasonic time is 20 min, and the magnetic stirring time is 12 h; S2. An initiator is added to the mixture to initiate the polymerization reaction, generating polyaniline between the graphite layers, thereby increasing the interlayer spacing. The initiator is a 0.03 g / mL ammonium persulfate solution. The polymerization reaction time is 30 h. The liquid-to-solid ratio of the initiator to the aniline monomer is 3 mL: 0.2 g. S3. The polymerized product was placed in a container filled with anhydrous ethanol and ultrasonically cleaned to remove impurities. After drying, the product was ultrasonically cleaned for 60 minutes. The drying temperature was 60℃, yielding a graphite@polyaniline composite material with a graphite interlayer spacing of 0.35 nm and a specific surface area of ​​350 m². 2 / g.

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