A fully rhombic molecular channel graphdiyne, its preparation method and application

Abstract

This invention provides a method for preparing graphyne with all rhombic molecular channels, comprising: S1 ultrasonically cleaning a copper foil in a hydrochloric acid solution to obtain a pretreated copper foil substrate; S2 placing the pretreated copper foil substrate in a double-necked flask containing a palladium catalyst, adding a reaction solvent, and refluxing to obtain an activated copper foil substrate; S3 adding a polybrominated benzene and a magnetic particle sequentially to another double-necked flask, placing the activated copper foil substrate in the flask, and then adding a reaction solvent to obtain a reaction system; S4 dissolving the polyyneylbenzene in the reaction solvent to obtain a first mixed solution, adding the first mixed solution to the reaction system for synthesis to obtain graphyne with all rhombic molecular channels. By using trisubstituted and hexasubstituted monomers for cross-coupling reactions, a two-dimensional conjugated carbon framework with all molecular channels being rhombic is precisely constructed, synthesizing a graphyne-like carbon material with all molecular channels being rhombic.

Description

Technical Field

[0001] This invention relates to the field of energy storage materials technology, and in particular to a fully rhombic molecular channel graphdiyne, its preparation method and application. Background Technology

[0002] Currently, commercially available anode materials mainly focus on two major technical routes: graphite and hard carbon. Anode materials for lithium-ion batteries need to meet several conditions: high conductivity, numerous active sites, strong charge adsorption activity, wide band gap, relatively large pore size and interlayer spacing, and low migration barrier. However, graphite has too small an interlayer spacing, and hard carbon has uneven pore size distribution, both of which affect the performance of lithium-ion batteries.

[0003] Graphdiyne is an excellent material that meets the above conditions. The charge adsorption and desorption processes of graphdiyne, as well as the diffusion kinetics of lithium ions in the bulk phase of the battery material, affect the energy and power characteristics of lithium-ion batteries, respectively. Since the discovery of graphdiyne, sp and sp² hybridized carbon atoms are connected by covalent bonds according to periodic rules, leading to the discovery of more topological structures, such as primitive graphdiyne with triangular pore structures and hexagonal pore structures, hydrogen-substituted and nitrogen-substituted graphdiyne, etc., endowing them with potential applications in gas separation, catalysis, and especially in energy-related fields.

[0004] Graphdiyne-based lithium-ion batteries (LIBs) combine the characteristics of two-dimensional and porous materials, exhibiting excellent electron transport performance. Their large surface area and porous channels can accommodate metal ions such as lithium ions. The triangular molecular structure of Graphdiyne can form LiC3, which adsorbs lithium on its surface, with a theoretical specific capacity of approximately 744 mA hg. 1 Three possible storage sites exist. Although the lithium diffusion direction is not limited to parallel to the interlayer plane of the graphyne layer, the pore size is still relatively small, limiting its rate performance. Graphyne films with a large hexagonal molecular structure can serve as freestanding flexible electrodes for lithium-ion batteries, achieving high efficiency at 0.1 A g / L. 1 The reversible capacity at the current density is 1050 mA hg 1 The pore size is so large that it is also suitable for storing Na ions, but at the same time, the large pore size makes the active sites more sparse.

[0005] It is evident that neither excessively small nor excessively large pore sizes can maximize the efficiency of Li-ion storage, making the preparation of carbon materials with suitable pore sizes a significant challenge. Therefore, designing the molecular pores of anode materials can improve the energy density and power density of lithium-ion batteries, achieving the goal of developing high-speed batteries. Summary of the Invention

[0006] To address the technical problems in existing technologies, this invention provides a fully rhombic molecular channel graphyne, its preparation method, and its applications. This invention employs a bottom-up molecular design and coupling reaction strategy to construct a graphyne carbon material with a regular rhombic channel structure. This fully rhombic molecular channel graphyne is composed of benzene rings and acetylene bonds, forming a uniformly rhombic molecular channel graphyne material with a large number of metal ion storage sites and transport channels. It can provide an actual lithium storage capacity of up to 2400 mAh / g at a current density of 50 mA / g, demonstrating significant practical value.

[0007] The primary objective of this invention is to provide a method for preparing fully rhombic molecular-pore graphdiyne, the method comprising: S1 The copper foil is ultrasonically cleaned in hydrochloric acid solution and dried under an inert atmosphere to obtain a pretreated copper foil substrate; S2. The pretreated copper foil substrate is placed in a double-necked flask containing a palladium catalyst, and a reaction solvent is added to it. The mixture is then stirred and refluxed to obtain an activated copper foil substrate. S3. In another double-necked flask, polybrominated benzene and magnetic particles are added in sequence. Under an inert atmosphere, the activated copper foil substrate is placed in the double-necked flask, sealed, and then the gas is replaced. Then, the reaction solvent is added to obtain the reaction system. S4 dissolves polyacetylenoid benzene in a reaction solvent to obtain a first mixed solution. The first mixed solution is added to the above reaction system to carry out the synthesis reaction. After the reaction is completed, graphdiyne with full rhombic molecular channels is obtained on a copper foil substrate.

[0008] Specifically, the concentration of the hydrochloric acid solution in step S1 is 2 M; the ultrasonic cleaning time is 5-10 min.

[0009] Specifically, the palladium catalyst in step S2 is bis(triphenylphosphine)palladium dichloride; the first reaction substrate is a polybrominated benzene or a polyiodinated benzene, wherein the polybrominated benzene is 1,3,5-tribromobenzene or hexabromobenzene; the polyiodinated benzene is 1,3,5-triiodobenzene or hexaiodobenzene; the palladium catalyst is tetratriphenylphosphine palladium dichloride or bis(triphenylphosphine)palladium dichloride; the reflux treatment in step S2 is carried out at 80°C for 30-60 minutes.

[0010] Specifically, the reflux treatment in step S2 is carried out at 80°C for 30-60 minutes.

[0011] Specifically, the molar ratio of the polybrominated benzene or polyiodobenzene in step S3 to the polyynylbenzene in step S4 is (0.8~2):(1.8~2.2), and the molar ratio is further preferably 1:2.

[0012] Specifically, in step S4, the second reaction substrate is polyynylbenzene, trihalobenzene, trichlorotriazine, or triynyltriazine; wherein the polyynylbenzene is 1,3,5-triynylbenzene or hexaethynylbenzene; and the trihalobenzene is 1,3,5-tribromobenzene or 1,3,5-triiodobenzene.

[0013] Specifically, the reaction solvent is triethylamine or a mixture of triethylamine with one or more of tetrahydrofuran, pyridine, acetone, and dimethylformamide; the inert gas is argon.

[0014] Specifically, the concentrations of the first and second reaction substrates in the reaction system are both 0.1~2 mg / mL.

[0015] Specifically, the reaction temperature of the synthesis reaction in step S4 is 50-100℃, and the reaction time is 1-7 days.

[0016] The second objective of this invention is to provide a fully rhombic molecular-pore graphdiyne prepared by the above-described preparation method, wherein the fully rhombic molecular-pore graphdiyne is composed of two elements, carbon and hydrogen, with a carbon-to-hydrogen ratio of 5:1.

[0017] The third objective of this invention is to provide an application of the above-described fully rhombic molecular channel graphyne in the field of energy storage.

[0018] Compared with the prior art, the beneficial effects of the present invention include: (1) This invention provides a graphyne material with a fully rhombic molecular channel structure, its preparation method, and its application. Through a bottom-up molecular design strategy, such as selecting trisubstituted (1,3,5-triethynylbenzene or 1,3,5-tribromobenzene, etc.) and hexasubstituted (hexabromobenzene or hexaethynylbenzene) monomers for cross-coupling reactions, a two-dimensional conjugated carbon skeleton in which all molecular channels are rhombic is precisely constructed. This solves the problem of excessively small (e.g., triangular channels) or excessively large (e.g., hexagonal channels) pore sizes in existing graphyne materials, and achieves a synergistic match between theoretical specific capacity and ion migration pore size. The prepared fully rhombic graphodyne not only possesses a high specific capacity but also provides a low-barrier migration channel for the rapid insertion and extraction of lithium ions, significantly improving the rate performance and cycle stability of the electrode material. It exhibits an actual lithium storage capacity of up to 2400 mAh / g at a current density of 50 mA / g and can still maintain a high capacity of 750 mAh / g at a high rate of 2000 mA / g. At the same time, it has excellent cycle stability (high capacity retention after 1000 cycles, with an average coulombic efficiency of 99.8%), providing a new solution for developing next-generation lithium-ion battery anode materials with both high energy density and high power density. (2) This invention employs an in-situ grown palladium-copper catalytic cross-coupling reaction to directly synthesize a self-supporting film on a copper foil current collector, forming a precisely controllable graphyne with a fully rhombic molecular channel structure. Rhombic graphyne is a carbon-rich polymer whose units are composed of 18-C rhombic structures, linked by acetylene bonds ( C≡C It connects four benzene rings; it has a moderate atomic density, moderately sized pores and H groups in the pores, which not only provide a large number of uniformly distributed active adsorption sites for lithium ions, but also construct a low-energy-barrier, isotropic three-dimensional ion fast transport network; the hydrogen atoms exposed in the pores further enhance the adsorption capacity for lithium ions, and can provide a large number of storage and transport channels for metal ions. (3) In terms of preparation method, the present invention adopts in-situ growth of palladium-copper catalytic cross-coupling reaction to directly synthesize self-supporting films on copper foil current collectors. The method is simple and mild (50-100℃), avoiding the complex precursor protection / deprotection steps and subsequent film formation process in traditional methods. By precisely controlling the molar ratio of the two monomers (1.8-2.2), solvent system and reaction parameters, the high selectivity and high yield of the reaction are ensured, and side reactions are effectively suppressed. Thus, it is possible to prepare structurally complete and defect-controllable full-rhombic pore graphdiyne films on a large scale and with high quality, laying a solid process foundation for their practical application. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the reaction process of the fully rhombic molecular channel graphyne prepared in Example 2 of the present invention; Figure 2 A schematic diagram of the reaction process of the fully rhombic molecular channel graphyne prepared in Example 7 of the present invention; Figure 3 A schematic diagram of the reaction process for preparing fully rhombic molecular channel graphyne in Example 9 of the present invention; Figure 4 This is a molecular framework structure diagram of the fully rhombic molecular channel graphdiyne prepared in Example 1 of the present invention; Figure 5 This is a scanning electron microscope image of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of the present invention; Figure 6Here is a high-resolution electron microscope image of the fully rhombic molecular channel graphdiyne prepared in Example 1 of this invention; Figure 7 The Raman spectrum of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of this invention; Figure 8 The infrared spectrum of the fully rhombic molecular channel graphdiyne prepared in Example 1 of this invention; Figure 9 The solid-state NMR spectrum of the fully rhombic molecular channel graphdiyne prepared in Example 1 of this invention; Figure 10 The charge-discharge cycle test diagram of the lithium battery with all-rhombic molecular channel graphdiyne as cathode prepared in Example 1 of the present invention. Figure 11 The image shows the cycle stability test results of a lithium battery using fully rhombic molecular channel graphdiyne prepared in Example 1 of this invention as the cathode. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention.

[0022] Example 1 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain the activated copper foil substrate. S3 added 137 mg (0.25 mmol) hexabromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 100 mL of triethylamine was added to obtain the reaction system. S4 dissolved 150 mg (0.5 mmol) of 1,3,5-triethynylbenzene in 75 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 3 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 1 on the copper foil substrate, with a yield of 98.3%.

[0023] Example 2 Please see Figure 1 , Figure 1 This is a schematic diagram of the reaction process for preparing fully rhombic molecular-pore graphdiyne in Example 2 of the present invention; the details are as follows: S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 5 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain the activated copper foil substrate. S3 added 157 mg (0.5 mmol) of 1,3,5-tribromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 150 mL of triethylamine was added to obtain the reaction system. S4 dissolves 55 mg (0.25 mmol) of hexaethynylbenzene in 60 mL of triethylamine to obtain a first mixed solution. The first mixed solution is added to the above reaction system and the synthesis reaction is carried out at 60 °C under an argon atmosphere for 3 days. After the reaction is completed, the copper foil substrate is washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 2 on the copper foil substrate, with a yield of 98.5%.

[0024] Example 3 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 8 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 60 min to obtain the activated copper foil substrate. S3 added 137 mg (0.25 mmol) of hexabromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 100 mL of triethylamine was added to obtain the reaction system. S4 dissolved 120 mg (0.8 mmol) of 1,3,5-triethynylbenzene in 75 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 3 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 3 on the copper foil substrate, with a yield of 98.5%.

[0025] Example 4 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (2000 mL) and ultrasonically cleaned for 8 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 60 min to obtain the activated copper foil substrate. S3 added 157 mg (0.5 mmol) of tribromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 100 mL of triethylamine was added to obtain the reaction system. S4 dissolved 44 mg (0.2 mmol) hexaethynylbenzene in 60 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 3 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 4 on the copper foil substrate, with a yield of 77.5%.

[0026] Example 5 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 50 min to obtain the activated copper foil substrate. S3 added 110 mg (0.2 mmol) of hexabromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine was added to obtain the reaction system. S4 dissolved 150 mg (1 mmol) of 1,3,5-triethynylbenzene in 75 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 3 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 5 on the copper foil substrate, with a yield of 86.3%.

[0027] Example 6 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 50 min to obtain the activated copper foil substrate. S3 added 141 mg (0.45 mmol) of tribromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine was added to obtain the reaction system. S4 dissolved 55 mg (0.25 mmol) hexaethynylbenzene in 60 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 3 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 6 on the copper foil substrate, with a yield of 86.3%.

[0028] Example 7 Please see Figure 2 , Figure 2 A schematic diagram of the reaction process for preparing fully rhombic molecular-pore graphdiyne in Example 7 of this invention is shown below; in detail: S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 5 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of tetratriphenylphosphine palladium dichloride, and then 100 mL of a mixed reaction solvent of triethylamine and tetrahydrofuran (the volume ratio of triethylamine to tetrahydrofuran in the mixed reaction solvent was 1:1) was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain the activated copper foil substrate. S3 added 228 mg (0.5 mmol) of 1,3,5-triiodobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine and tetrahydrofuran (the volume ratio of triethylamine to tetrahydrofuran was 5:1) were added to the flask to obtain the reaction system. S4 dissolves 55.5 mg (0.25 mmol) of hexaethynylbenzene in 75 mL of triethylamine and tetrahydrofuran to obtain a first mixed solution. The first mixed solution is added to the above reaction system and the synthesis reaction is carried out at 80 °C under an argon atmosphere for 5 days. After the reaction is completed, the copper foil substrate is washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 7 on the copper foil substrate, with a yield of 86.7%.

[0029] Example 8 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 5 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of tetratriphenylphosphine palladium dichloride, and then 100 mL of a mixed reaction solvent of triethylamine and pyridine was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain an activated copper foil substrate. S3 added 208 mg (0.25 mmol) of hexaiodobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine and pyridine (the volume ratio of triethylamine to pyridine was 1:1) were added to obtain the reaction system. S4 dissolves 75 mg (0.5 mmol) of 1,3,5-triethynylbenzene in 75 mL of triethylamine and pyridine to obtain a first mixed solution. The first mixed solution is added to the above reaction system and the synthesis reaction is carried out at 80 °C under an argon atmosphere for 5 days. After the reaction is completed, the copper foil substrate is washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 8 on the copper foil substrate, with a yield of 88.2%.

[0030] Example 9 Please see Figure 3 , Figure 3A schematic diagram of the reaction process for preparing fully rhombic molecular-pore graphdiyne in Example 9 of this invention is shown below; in detail: S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 8 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of tetratriphenylphosphine palladium dichloride, and then 100 mL of a mixed reaction solvent of triethylamine and acetone was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain an activated copper foil substrate. S3 added 55 mg (0.25 mmol) of hexaethynylbenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine and pyridine (the volume ratio of triethylamine to pyridine was 5:1) were added to obtain the reaction system. S4 dissolved 92.2 mg (0.5 mmol) of trichlorotriazine in 75 mL of triethylamine and pyridine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 50 °C under an argon atmosphere for 7 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 9 on the copper foil substrate, with a yield of 78.6%.

[0031] Example 10 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 8 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of tetratriphenylphosphine palladium dichloride, and then 100 mL of a mixed reaction solvent of triethylamine and dimethylformamide was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain an activated copper foil substrate. S3 added 208 mg (0.25 mmol) of hexaiodobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine and pyridine (the volume ratio of triethylamine to dimethylformamide was 5:1) were added to obtain the reaction system. S4 dissolved 76.5 mg (0.5 mmol) of triynyltriazine in 75 mL of triethylamine and dimethylformamide to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 90 °C under an argon atmosphere for 2 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 10 on the copper foil substrate, with a yield of 76.8%.

[0032] Example 11 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 8 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of tetratriphenylphosphine palladium dichloride, and then 100 mL of a mixed reaction solvent of triethylamine and dimethylformamide was added. The mixture was stirred and refluxed at 80 °C for 30 min to obtain an activated copper foil substrate. S3 added 137 mg (0.25 mmol) of hexabromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine and pyridine (the volume ratio of triethylamine to dimethylformamide was 5:1) were added to obtain the reaction system. S4 dissolved 92.2 mg (0.5 mmol) trichlorotriazine in 75 mL of triethylamine and dimethylformamide to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 90 °C under an argon atmosphere for 2 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 11 on the copper foil substrate, with a yield of 84.2%.

[0033] Example 12 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 50 min to obtain the activated copper foil substrate. S3 added 228 mg (0.5 mmol) of 1,3,5-triiodobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 100 mL of triethylamine was added to obtain the reaction system. S4 dissolved 55 mg (0.25 mmol) hexaethynylbenzene in 60 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 2 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 12 on the copper foil substrate, with a yield of 74.5%.

[0034] Example 13 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 50 min to obtain the activated copper foil substrate. S3 added 208 mg (0.25 mmol) of hexaiodobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 100 mL of triethylamine was added to obtain the reaction system. S4 dissolved 75 mg (0.5 mmol) of 1,3,5-triethynylbenzene in 75 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 7 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 13 on the copper foil substrate, with a yield of 98.3%.

[0035] Example 14 S1. Ten copper foils (10×10 cm²) were placed in 2 M hydrochloric acid solution (200 mL) and ultrasonically cleaned for 10 min. Then, they were rinsed three times each with water, ethanol and acetone, and dried under argon atmosphere to obtain the pretreated copper foil substrate. S2. The pretreated copper foil substrate was placed in a double-necked flask containing 100 mg of bis(triphenylphosphine)palladium dichloride, and then 100 mL of triethylamine was added. The mixture was stirred and refluxed at 80 °C for 50 min to obtain the activated copper foil substrate. S3 added 157 mg (0.5 mmol) of tribromobenzene and a magnetic ball to another double-necked flask, introduced argon gas, placed the activated copper foil substrate in the double-necked flask, sealed it, and then performed gas replacement. Subsequently, 120 mL of triethylamine was added to obtain the reaction system. S4 dissolved 55 mg (0.25 mmol) hexaethynylbenzene in 60 mL of triethylamine to obtain a first mixed solution. The first mixed solution was added to the above reaction system and the synthesis reaction was carried out at 60 °C under an argon atmosphere for 7 days. After the reaction was completed, the copper foil substrate was washed with acetone and ethanol to obtain the fully rhombic molecular channel graphdiyne prepared in Example 14 on the copper foil substrate, with a yield of 97.8%.

[0036] Performance testing Figure 4 This is a molecular framework structure diagram of the fully rhombic molecular channel graphdiyne prepared in Example 1 of the present invention; as shown. Figure 4 As shown, the structure of rhombic graphyne possesses a large π-conjugated system, which can meet the requirement of good conductivity in batteries. The fully rhombic molecularly porous graphyne prepared in Example 1 was subjected to 6° min on a Bruker D8 ADVANCE. -1 The scanning velocity was recorded using Cu Kα radiation (λ=1.5406 Å). Morphological details were observed using field emission scanning electron microscopy (FESEM, Hitachi S-4800) and transmission electron microscopy (TEM, Hitachi H-7650). Figure 5 This is a scanning electron microscope image of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of the present invention; Figure 6 Here is a high-resolution electron microscope image of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of this invention; as shown Figure 5 and Figure 6 As shown, it is a three-dimensional (3D) porous membrane composed of interconnected porous domains, with a hierarchical porous structure. Its characteristic feature is the presence of a large number of micron-sized macropores and tens of nanometer-sized mesopores. This structure has a larger surface area and higher porosity, providing abundant ion transport channels and active sites for lithium storage.

[0037] The chemical structure of the fully rhombic molecular-pore graphyne prepared in Example 1 was characterized by Fourier transform infrared spectroscopy (FT-IR, Thermo Fisher Nicolet iN10) and Raman spectroscopy (Thermo Scientific DXRxi, 532 nm). Figure 7 The Raman spectrum of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of this invention; as shown Figure 7 As shown, 1550 cm was observed. -1 G-band at 1450 cm -1The D bands represent numerous structural defects and edges of benzene rings and rhombic graphynyne, respectively. Meanwhile, the 2000 and 2200 cm⁻¹ bands... -1 The prominent y-peaks nearby correspond to C≡C acetylene bonds, demonstrating the abundance of acetylene bonds in rhombic graphynyne. For example... Figure 8 As shown, Figure 8 The infrared spectrum of the fully rhombic molecular-pore graphdiyne prepared in Example 1 of this invention; 2345 cm⁻¹ in the Fourier transform infrared spectrum (FT-IR). -1 The peak at 1350 also corresponds to typical acetylene bond stretching vibrations, which is consistent with Raman spectroscopy results. Furthermore, 1350... 1600 cm -1 The prominent peak in the vicinity is attributed to the skeletal vibrations of the benzene ring. 2925 cm⁻¹ -1 The peak value is attributed to the tensile vibration of CAr-H in rhombic graphynylene, 842 cm⁻¹ -1 The peaks correspond to out-of-plane bending vibrations. X-ray photoelectron spectroscopy (XPS) was performed on a VG Scientific ESCALab220i XL X-ray photoelectron spectrometer using Al Kα radiation as the excitation source. The solid-state NMR spectrum of the prepared rhombic graphyne is shown below. Figure 9 As shown, Figure 9 This is the solid-state NMR spectrum of the fully rhombic molecular-pore graphyne prepared in Example 1 of this invention; the structure of the rhombic graphyne contains four carbon species and four functional groups. The solid-state NMR results clearly demonstrate the chemical structure of the rhombic graphyne. The rhombic graphyne framework mainly contains four carbon species. Peaks appear at 122.8 and 133.3, corresponding to aromatic CC and CHCH sites. The peaks at 75.5 and 81.1 can be attributed to C(sp)-C(sp) and C(sp)-C(sp2) sites.

[0038] Electrochemical measurements were performed using CR2032 button cells assembled in an argon-filled glove box. Half-cells were assembled using rhombic graphdiyne prepared in Example 1 as the cathode, Li metal foil as the anode, a polypropylene membrane (Celgard 2500), and a liquid electrolyte (ethylene carbonate and dimethyl carbonate, volume ratio 1:1). The liquid electrolyte contained 1.0 M LiPF6 for the LIB. For the SIB, sodium metal glass fibers (ethylene carbonate and dimethyl carbonate, volume ratio 1:1) with 1.0 M NaClO4 and 5% fluoroethylene carbonate (FEC) additives were used.

[0039] Half-cells were assembled and cycled between 0.005V and 3V using the LAND cell testing system. The thickness of the 1 cm⁻¹ cell is (700 nm–2.9 μm). 2The rhombic graphyne electrode region is used for electrochemical measurements in a standalone form. The active material is a standalone rhombic graphyne film (0.1–0.25 mg) without any additives. Figure 10 The charge-discharge cycle test diagram of the lithium battery with all-rhombic molecular channel graphdiyne as cathode prepared in Example 1 of the present invention. Figure 11 The image shows the cycle stability test results of a lithium battery using the fully rhombic molecular-channel graphdiyne prepared in Example 1 of this invention as the cathode. The coin cell assembled with the prepared rhombic graphdiyne can provide an actual lithium storage capacity of up to 2400 mAh / g at a current density of 50 mA / g, and the charge-discharge cycle diagram at a current density of 0.5 A / g is shown below. Figure 10 As shown, after 1000 cycles, the active material exhibits a specific capacity of approximately 2000 mAh / g, with an average charge / discharge efficiency of 99.8%.

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing graphdiyne with fully rhombic molecular channels, characterized in that, The preparation method includes: S1 The copper foil is ultrasonically cleaned in hydrochloric acid solution and dried under an inert atmosphere to obtain a pretreated copper foil substrate; S2. The pretreated copper foil substrate is placed in a double-necked flask containing a palladium catalyst, and a reaction solvent is added to it. The mixture is then stirred and refluxed to obtain an activated copper foil substrate. S3. The first reaction substrate and magnetic ball are added to another double-necked flask in sequence. Under an inert atmosphere, the activated copper foil substrate is placed in the double-necked flask, sealed, and then the gas is replaced. Then the reaction solvent is added to obtain the reaction system. S4 dissolves the second reaction substrate in a reaction solvent to obtain a first mixed solution. The first mixed solution is then added to the above reaction system to carry out the synthesis reaction. After the reaction is completed, fully rhombic molecular channel graphyne is obtained on a copper foil substrate.

2. The preparation method according to claim 1, characterized in that, The concentration of the hydrochloric acid solution in step S1 is 2 M; the ultrasonic cleaning time is 5-10 min.

3. The preparation method according to claim 1, characterized in that, The palladium catalyst in step S2 is bis(triphenylphosphine)palladium dichloride; the first reaction substrate is a polybrominated benzene or a polyiodophenyl, wherein the polybrominated benzene is 1,3,5-tribromobenzene or hexabromobenzene; the polyiodophenyl is 1,3,5-triiodobenzene or hexaiodobenzene; the palladium catalyst is tetratriphenylphosphine palladium dichloride or bis(triphenylphosphine)palladium dichloride; the reflux treatment in step S2 is carried out at 80°C for 30-60 minutes.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the polybrominated benzene or polyiodobenzene in step S3 to the polyynylbenzene in step S4 is (0.8~2):(0.8~2.2), and the molar ratio is further preferably 1:

2.

5. The preparation method according to claim 1, characterized in that, In step S4, the second reaction substrate is polyynylbenzene, trihalobenzene, trichlorotriazine, or triynyltriazine; wherein the polyynylbenzene is 1,3,5-triynylbenzene or hexaethynylbenzene; and the trihalobenzene is 1,3,5-tribromobenzene or 1,3,5-triiodobenzene.

6. The preparation method according to claim 1, characterized in that, The reaction solvent is triethylamine or a mixture of triethylamine with one or more of tetrahydrofuran, pyridine, acetone, and dimethylformamide; the inert gas is argon.

7. The preparation method according to claim 1, characterized in that, The concentrations of the first and second reaction substrates in the reaction system are both 0.1~2 mg / mL.

8. The preparation method according to claim 1, characterized in that, The reaction temperature of the synthesis reaction described in step S4 is 50-100℃, and the reaction time is 1-7 days.

9. A fully rhombic molecularly porous graphdiyne prepared by the preparation method according to claims 1-8, characterized in that, The fully rhombic molecular channel graphyne is composed of two elements, carbon and hydrogen, with a carbon-to-hydrogen ratio of 5:

1.

10. An application of the fully rhombic molecular channel graphyne as described in claim 9 in the field of energy storage.

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