Carbon molecular sieve, method of making, electrode, battery, and supercapacitor

Abstract

The application belongs to the technical field of carbon materials, and discloses a preparation method of carbon molecular sieve with super-high specific surface area, an electrode, a battery and a supercapacitor. Molecular sieves with different structures are used as templates, which are placed in saturated carbon source steam for sufficient absorption, and trimethylbenzene is used to clean the surface of the unabsorbed carbon source and to wash, then the obtained mixture is placed in a tube furnace, heated and reacted under a nitrogen atmosphere to obtain an intermediate; the molecular sieve template in the intermediate is removed, washed and dried to obtain the final product. The application firstly proposes to fill the template with carbon source steam; the prepared carbon molecular sieve has super-high specific surface and high structural regularity; the carbon molecular sieve used as a sodium battery electrode material can achieve excellent overall performance.

Description

Technical Field

[0001] This invention belongs to the field of carbon materials technology, and relates to a method for preparing carbon molecular sieves with ultra-high specific surface area and their application in electrodes, batteries and supercapacitors. Background Technology

[0002] Carbon molecular sieves are a general term for a class of carbon materials with regular pore structures. Carbon molecular sieves prepared using zeolite molecular sieves as hard templates possess the regular microporous channels of the zeolite molecular sieve template and are expected to be widely used in adsorption, batteries, capacitors, electrocatalysis, and other fields. Currently, the main methods for preparing these carbon molecular sieves include vacuum impregnation, chemical vapor deposition (CVD), and a two-step method coupling vacuum impregnation and CVD. Among these, vacuum impregnation is simple, but the prepared carbon molecular sieves have poor regularity and low specific surface area; the two-step method is complex, but the prepared samples have regular microporous structures and high specific surface areas; CVD falls somewhere in between. Therefore, current preparation technologies cannot simultaneously meet the requirements of good material properties and ease of preparation, and these limitations significantly restrict the development of this type of carbon molecular sieve. Summary of the Invention

[0003] To address the problems of irregular pores and low specific surface area in currently prepared carbon molecular sieves, this invention provides a method for preparing carbon molecular sieves with ultra-high specific surface area and extends their application in electrodes, batteries, and supercapacitors.

[0004] The purpose of this invention is to provide a carbon molecular sieve with an ultra-high specific surface area. The preparation method of the ultra-high specific surface area carbon molecular sieve includes: placing a molecular sieve template in saturated carbon source vapor under a certain pressure, and absorbing it to obtain a mixture;

[0005] Use trimethylbenzene to clean the carbon source off the surface of the mixture, and then evaporate any remaining trimethylbenzene.

[0006] The washed mixture was transferred to a tube furnace, heated and held at a temperature under a nitrogen atmosphere to obtain an intermediate.

[0007] The molecular sieve template in the intermediate was removed using acid, and the product was then washed and dried to obtain the final product.

[0008] Furthermore, the molecular sieve template is one of the following molecular sieves with the following structures: FAU, EMT, BPH, CHA, BEA.

[0009] Furthermore, the carbon source is one of the following substances: furfuryl alcohol, formamide, or ethylenediamine.

[0010] Furthermore, the amount of molecular sieve template used is 0.5-10g, and the pressure of saturated carbon source vapor is 10KPa-100KPa.

[0011] Further, the cleaned mixture is transferred to a tube furnace and reacted at 100-200℃ for 2-10 hours under a nitrogen atmosphere, and then the temperature is raised to 600-1000℃ for another 2-10 hours.

[0012] Furthermore, the acid solution is prepared in a ratio of HF:HCl = 1:0 to 1:1.

[0013] Another objective of this invention is to provide an electrode material, wherein the electrode material is prepared by uniformly mixing the carbon molecular sieve material with ultra-high specific surface area, a binder, and acetylene black into a slurry, using carbon-coated copper foil as the current collector, and pressing it into a sheet; the ratio of carbon molecular sieve: binder: acetylene black is 8:1:1-9:0.5:0.5.

[0014] Another object of the present invention is to provide a battery that uses the aforementioned electrodes.

[0015] Another object of the present invention is to provide a supercapacitor that uses the aforementioned electrodes.

[0016] The advantages and positive effects of this invention, combining all the above technical solutions, are as follows: Based on the characteristics of carbon materials themselves, this invention selects a suitable carbon source and uses the principle of vacuum vapor deposition to obtain a carbon molecular sieve with a complete structure, uniform pores, and ultra-high specific surface area. The prepared carbon molecular sieve exhibits excellent structural integrity, ultra-high specific surface area, and regular microporous structure.

[0017] This invention is the first to propose a vacuum steam impregnation method for preparing carbon molecular sieves; the carbon molecular sieves prepared by this method have a regular microporous structure and an ultra-high specific surface area; the preparation method is simple to operate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the preparation method of carbon molecular sieve with ultra-high specific surface area provided in the embodiments of the present invention.

[0020] Figure 2 This is a schematic diagram of the preparation method of carbon molecular sieve with ultra-high specific surface area provided in the embodiment of the present invention.

[0021] Figure 3 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images of the materials prepared according to embodiments of the present invention.

[0022] Figure 4 These are the nitrogen adsorption-desorption curves and pore size distribution diagrams of the materials prepared according to the embodiments of the present invention.

[0023] Figure 5 This is a performance characterization of the material prepared according to the embodiments of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed description of the invention is provided in conjunction with embodiments, but this is not intended to limit the invention.

[0025] To address the problems existing in the prior art, this invention provides a carbon molecular sieve with ultra-high specific surface area, a preparation method, an electrode, a battery, and a supercapacitor. The invention will be described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the method for preparing carbon molecular sieves with ultra-high specific surface area provided by the present invention includes the following steps:

[0027] S101: Place 0.5-10g of FAU, EMT, BPH, CHA or BEA molecular sieve template in a 10-100KPa pressure environment, introduce saturated furfuryl alcohol vapor, and absorb to obtain a mixture.

[0028] S102: Take 1-5g of the mixture, add 50ml of trimethylbenzene, stir thoroughly and then centrifuge; place the separated product in an 80℃ oven for 24h to fully evaporate the trimethylbenzene.

[0029] S103: Transfer the cleaned mixture to a tube furnace and react at 100-200℃ for 2-10 hours under a nitrogen atmosphere, then raise the temperature to 600-1000℃ and react for another 2-10 hours.

[0030] S104: The molecular sieve template is removed using an acid solution with a ratio of HF:HCl = 1:0 to 1:1. After washing and drying, the final product is obtained.

[0031] The method for preparing carbon molecular sieves with ultra-high specific surface area provided by this invention can also be implemented by those skilled in the art using other steps. Figure 1 The method for preparing carbon molecular sieves with ultra-high specific surface area provided by the present invention is merely one example.

[0032] This invention involves uniformly mixing the prepared carbon molecular sieve with a binder and acetylene black to form a slurry. Using carbon-coated copper foil as the current collector, the mixture is pressed into a sheet to prepare an electrode. A three-electrode system is assembled using the electrode material as the working electrode, a mercury oxide electrode as the reference electrode, and a platinum sheet as the counter electrode. The electrochemical performance of the electrode material is then tested. The mass ratio of carbon material: binder: acetylene black is 8:1:1-9:0.5:0.5.

[0033] This invention proposes a vacuum vapor impregnation strategy for preparing carbon molecular sieves with ultra-high specific surface area. The carbon molecular sieves prepared by this method have a regular microporous structure and ultra-high specific surface area, and the preparation method is simple to operate. When applied to electrochemical performance, the initial discharge specific capacity and initial charge specific capacity can reach 1714 mAh / g and 288 mAh / g, respectively, without any activation treatment. Structural characterization shows that this method can provide numerous defect sites for sodium ion insertion and extraction for ion storage. The above preparation process does not have harsh preparation techniques or special requirements, and is simple and easy to operate.

[0034] The invention will now be further described in conjunction with experimental data.

[0035] In this invention, Figure 2 This is the process flow for preparing carbon molecular sieves with ultra-high specific surface area.

[0036] Figure 3 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the prepared material.

[0037] Figure 4 It refers to the pore size distribution effect of the prepared material.

[0038] Figure 5 It is the cyclic voltammetry and constant current charge-discharge effect that characterize the performance.

[0039] Experiments show that:

[0040] Traditional liquid-phase impregnation methods result in carbon molecular sieves with small specific surface areas and unstable structures. The steam impregnation method in this invention can achieve ultra-high specific surface areas and uniform pore sizes, thereby improving performance.

[0041] Based on the characteristics of carbon materials, this invention selects a suitable carbon source and uses a steam impregnation method to fully fill the pores of a molecular sieve template, thereby obtaining a carbon molecular sieve with an ultra-high specific surface area. The prepared carbon molecular sieve exhibits excellent overall performance.

[0042] This invention is the first to propose a steam impregnation method for preparing carbon molecular sieves. The carbon molecular sieves prepared by this method have a regular microporous structure and an ultra-high specific surface area. Experiments have shown that the carbon molecular sieves prepared by this invention exhibit excellent overall performance when used as electrode materials for sodium batteries. The preparation method is simple to operate.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, in accordance with the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing carbon molecular sieves with ultra-high specific surface area, characterized in that, The method for preparing the carbon molecular sieve with ultra-high specific surface area includes: A molecular sieve template was placed in saturated furfuryl alcohol vapor under a certain pressure to absorb and obtain a mixture; the amount of molecular sieve template used was 0.5-10 g, and the reaction pressure was 10 kPa. Use trimethylbenzene to wash off the furfuryl alcohol from the surface of the mixture, and then evaporate the remaining trimethylbenzene. The washed mixture was transferred to a tube furnace and reacted at 100-200℃ for 2-10 h under a nitrogen atmosphere. Then, the temperature was raised to 600-1000℃ and reacted for another 2-10 h to obtain an intermediate. The molecular sieve template in the intermediate was removed using acid, and the intermediate was washed and dried to obtain the final product. The molecular sieve templates mentioned above are one of the following molecular sieves with the following structures: FAU, EMT, BPH, CHA, and BEA.

2. The method for preparing carbon molecular sieves with ultra-high specific surface area as described in claim 1, characterized in that, Take 1-5g of the mixture, add 50ml of trimethylbenzene, stir thoroughly and then centrifuge; place the separated product in an 80℃ oven for 24h to fully evaporate the trimethylbenzene.

3. The method for preparing carbon molecular sieves with ultra-high specific surface area as described in claim 1, characterized in that, The ratio of acid solution used is HF:HCl = 1:0 to 1:

1.

4. A carbon molecular sieve with ultra-high specific surface area prepared by the preparation method of carbon molecular sieve with ultra-high specific surface area according to any one of claims 1 to 3.

5. An electrode, characterized in that, The electrode is prepared by mixing the carbon molecular sieve with ultra-high specific surface area obtained by the preparation method of carbon molecular sieve with ultra-high specific surface area according to any one of claims 1 to 3 with a binder and acetylene black to form a slurry, using copper foil as the current collector, and pressing it into a sheet to obtain the electrode. The ratio of carbon molecular sieve: binder: acetylene black is 8:1:1-9:0.5:0.

5.

6. A battery, characterized in that, The battery uses the electrode as described in claim 5.

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