CN-120774410-B - Preparation and application of high-performance asphalt-based porous carbon material

Abstract

The invention belongs to the technical field of energy storage materials, and particularly discloses a preparation method and application of a high-performance asphalt-based porous carbon material. The preparation method comprises the steps of pretreating asphalt, hydrothermally synthesizing cellulose ester from microcrystalline cellulose and phytic acid, compounding humic acid, hectorite powder and the cellulose ester, freeze-drying to obtain a compound auxiliary agent, carrying out microwave-hydrothermal reaction on pretreated asphalt and the compound auxiliary agent to form a precursor, activating the precursor, carbonate and phosphate in a multistage gradient atmosphere, and finally washing and drying to obtain the porous carbon material. According to the method, the composite auxiliary agent is used for cooperating with pore-forming and atmosphere activation to replace alkali etching, so that green controllable reaming and heteroatom uniform doping are realized, and a hierarchical pore structure is accurately constructed through multistage carbonization. The obtained material has a three-dimensional interpenetrating network, high specific surface area and excellent conductivity, can effectively buffer ion intercalation stress, remarkably improves electrochemical stability, inhibits volume expansion, and is suitable for negative electrodes of lithium and sodium ion batteries and super capacitor electrodes.

Inventors

• CHENG GUIGANG
• SHI XINGYU
• ZHAO LONG

Assignees

• 定远东昌碳基材料有限公司

Dates

Publication Date

20260512

Application Date

20250721

Claims (10)

1. 1. The preparation method of the high-performance pitch-based porous carbon material is characterized by comprising the following steps of: s1, crushing petroleum asphalt and vacuum drying to obtain pretreated asphalt; S2, mixing microcrystalline cellulose, phytic acid, sodium tripolyphosphate and urea, adding water to prepare slurry, stirring in an oil bath for reaction, washing with hot water to be neutral, and then drying in vacuum to obtain cellulose ester; S3, dispersing humic acid and hectorite powder in deionized water, adding cellulose ester, stirring uniformly at normal temperature, and crushing after freeze drying to obtain a composite auxiliary agent; S4, mixing the pretreated asphalt with a composite additive and ammonium persulfate, and performing hydrothermal reaction after microwave treatment to obtain a precursor; S5, mixing the precursor, carbonate and phosphate, performing multi-stage heating treatment under the nitrogen atmosphere, and switching to carbon dioxide to continue heating treatment to obtain an activated product; s6, circularly washing the activated product by using 80-90 ℃ hot water until the pH value of the filtrate is 6.8-7.2, and vacuum drying for 7-9h at 115-125 ℃ to obtain the high-performance asphalt-based porous carbon material.
2. 2. The preparation method according to claim 1, wherein the petroleum asphalt in the step S1 is crushed to a particle size of 6-8 μm, the vacuum drying temperature is 100-120 ℃, and the drying time is 6-8 hours.
3. 3. The preparation method according to claim 1, wherein in step S2, 10-13 parts by weight of microcrystalline cellulose, 7-10 parts by weight of phytic acid, 2-4 parts by weight of sodium tripolyphosphate, 3-5 parts by weight of urea, and 100-120 parts by weight of water are used.
4. 4. The preparation method according to claim 1, wherein in the step S3, 20-25 parts by weight of humic acid, 5-8 parts by weight of hectorite powder, 100-115 parts by weight of deionized water and 6-8 parts by weight of cellulose ester are used.
5. 5. The preparation method according to claim 1, wherein in the step S4, the pretreatment asphalt is 85-90 parts by weight, the composite additive is 15-20 parts by weight, and the ammonium persulfate is 0.5-0.9 part by weight, the hydrothermal reaction temperature is 170-180 ℃, and the reaction time is 3-5 hours.
6. 6. The method according to claim 1, wherein the carbonate in step S5 is at least one selected from the group consisting of potassium carbonate, sodium carbonate and lithium carbonate, and the phosphate is at least one selected from the group consisting of potassium phosphate, potassium hydrogen phosphate and sodium phosphate.
7. 7. The preparation method according to claim 1, wherein the precursor is 95-100 parts by weight, the carbonate is 25-30 parts by weight, and the phosphate is 8-12 parts by weight in step S5.
8. 8. The preparation method according to claim 1, wherein the multi-stage heating treatment in the step S5 comprises heating to 290-310 ℃ at 4-6 ℃ per min for 0.8-1.2h, heating to 740-800 ℃ at 7-9 ℃ per min for 1.8-2.2h, switching to carbon dioxide gas, and heating to 840-860 ℃ for 0.8-1.2h.
9. 9. A high performance pitch-based porous carbon material prepared by the preparation method of any one of claims 1 to 8.
10. 10. Use of the high performance pitch-based porous carbon material of claim 9 for the preparation of a lithium ion battery anode, a sodium ion battery anode or a supercapacitor electrode.

Description

Preparation and application of high-performance asphalt-based porous carbon material Technical Field The invention belongs to the technical field of energy storage materials, and particularly relates to preparation and application of a high-performance asphalt-based porous carbon material. Background The petroleum asphalt is used as a byproduct in the crude oil refining process, has the characteristics of high carbon content, adjustable molecular structure, low cost and the like, and has important application value in the field of porous carbon materials for energy storage devices. However, the strong pi-pi stacking effect among molecules leads to a compact graphitized structure easily formed during high-temperature treatment, so that the specific surface area of the asphalt-based carbon material prepared by the conventional process is generally too low, and the effective pore canal is not developed enough, so that the ion transmission dynamics performance is severely limited. In the prior art, the chemical activation method relies on strong alkali such as potassium hydroxide to promote the porosity, but corrosive reagents accelerate equipment loss, residual alkali metal impurities not only pollute the environment, but also damage the stability of an electrode interface, and part of the method needs to use highly toxic hydrofluoric acid to remove a template agent, so that the environmental risk and the disposal cost are greatly increased, the physical activation method has the advantages of environmental protection, but the pore size distribution is too wide and the mesoporous proportion is too low due to insufficient pre-oxidation of petroleum asphalt, so that a rapid ion transmission channel required by high-rate charge and discharge is difficult to support, the hard template process in the template auxiliary method needs a complex pickling process to remove the template, and the soft template rule has the defects of poor self-assembly controllability, low batch consistency and the like, and particularly when the chemical activation is combined, the industrial feasibility is obviously reduced through multiple post-treatment steps. The method is characterized in that the prior art is difficult to cooperatively solve two major core problems, namely, firstly, the uniform distribution of surface functional groups is destroyed in the high-temperature carbonization process, which leads to discontinuous conductive network of the material and remarkable rise of interface impedance of an electrode, and secondly, the binding force between a conventional polymer coating layer and a carbon matrix is weak, stripping failure is easy to occur under repeated embedding and releasing stress of ions, and structural pulverization caused by volume expansion cannot be effectively restrained. These defects commonly lead to the problems of rapid specific capacity decay, insufficient cycle life and the like of the existing asphalt-based carbon material in the application of lithium ion batteries, sodium ion batteries and super capacitors, and severely limit the popularization of the asphalt-based carbon material in high-performance energy storage devices. Therefore, development of a preparation method with high efficiency and green color is needed, and on the premise of avoiding use of toxic chemical reagents, precise regulation and control of a carbon material pore structure, optimization of a conductive network and strengthening of interface stability are synchronously realized. Disclosure of Invention The invention aims to provide a preparation method and application of a high-performance asphalt-based porous carbon material, wherein the preparation method replaces strong alkali etching by synergistic pore-forming and atmosphere activation of a composite auxiliary agent, and realizes green controllable pore expansion and heteroatom uniform doping; and (3) accurately constructing a hierarchical pore structure through multistage carbonization. The obtained material has a three-dimensional interpenetrating network, high specific surface area and excellent conductivity, can effectively buffer ion intercalation stress, remarkably improves electrochemical stability, inhibits volume expansion, and is suitable for negative electrodes of lithium and sodium ion batteries and super capacitor electrodes. The technical purpose of the invention is realized by the following technical scheme: the technical object of the first aspect of the present invention is to provide a method for preparing a high-performance pitch-based porous carbon material, comprising: S1, crushing petroleum asphalt to a particle size of 6-8 mu m, and vacuum drying at 100-120 ℃ for 6-8 hours to obtain pretreated asphalt; S2, mixing microcrystalline cellulose, phytic acid, sodium tripolyphosphate and urea, adding water to prepare slurry, stirring in an oil bath at 120-140 ℃ for reaction for 1-3 hours, washing with hot water at 58-62 ℃ to be neutral, and then drying in v