CN112830472A

CN112830472A - Preparation method of porous carbon, porous carbon obtained by preparation method and application of porous carbon

Info

Publication number: CN112830472A
Application number: CN202110068256.6A
Authority: CN
Inventors: 胡涵; 晁会霞; 刘海燕; 刘昭斌; 钱通; 邢涛; 黄运春; 李智; 张奎同; 韩嘉
Original assignee: Yankuang Group Corp Ltd; China University of Petroleum East China
Current assignee: Yankuang Group Corp Ltd; China University of Petroleum East China
Priority date: 2021-01-19
Filing date: 2021-01-19
Publication date: 2021-05-25
Anticipated expiration: 2041-01-19
Also published as: CN112830472B

Abstract

The invention provides a preparation method of porous carbon, the porous carbon obtained by the preparation method and application of the porous carbon. The preparation method of the porous carbon comprises the following steps: mixing petroleum asphalt with a template, calcining, and removing the residual template after calcining to obtain the porous carbon, wherein the template is basic magnesium carbonate and/or magnesium oxide. The invention particularly provides a preparation method of a petroleum-based two-dimensional porous carbon nanosheet and three-dimensional hierarchical porous carbon and application of the petroleum-based two-dimensional porous carbon nanosheet and the three-dimensional hierarchical porous carbon in a lithium ion capacitor. The double-carbon composite lithium ion capacitor constructed by the electrode active material prepared by the invention has high energy density and power density and excellent cycle stability.

Description

Preparation method of porous carbon, porous carbon obtained by preparation method and application of porous carbon

Technical Field

The invention belongs to the technical field of lithium ion capacitor preparation, and particularly relates to a preparation method of porous carbon, the porous carbon obtained by the porous carbon and application of the porous carbon, in particular to a preparation method of a petroleum-based two-dimensional porous carbon nanosheet and three-dimensional hierarchical porous carbon and application of the porous carbon in an energy storage electrode.

Background

With the further development of the energy storage field, the demand for a new energy storage device of the next generation that can satisfy both higher energy density and power density is increasing. In view of this, a new electrochemical energy storage device, metal ion capacitor, has been developed. The lithium ion capacitor is one of the metal ion capacitors, because the relatively mature lithium ion secondary battery research and development technology is a novel energy storage device which is developed most rapidly at present. Lithium ion capacitors generally comprise three parts: a battery-type negative electrode, a capacitor-type positive electrode, and a lithium-containing organic electrolyte. Thus, there are two different electrochemical energy storage mechanisms within a lithium ion capacitor, namely: ion intercalation/deintercalation at the negative electrode side and anion adsorption/desorption at the positive electrode side. Therefore, the lithium ion capacitor exhibits higher power density than the conventional secondary battery and higher energy density than the conventional supercapacitor.

At present, the negative electrode material of commercial lithium ion capacitors is mainly commercial graphite, and the positive electrode material is mainly activated carbon. But due to the lower specific capacity and the poorer cycle life of the commercial graphite and the activated carbon, the improvement of the energy density of the lithium ion container system is greatly limited. In general, the energy density of an electrochemical energy storage device is mainly determined by the energy storage behavior of the electrode material. Therefore, the development of a high-performance electrode material which is cheap and easy to obtain, simple and convenient to operate and low in cost is an effective measure for constructing a high-performance lithium ion capacitor and a future development trend.

The petroleum heavy oil is used as an intermediate product in the petroleum refining process, has low price, huge yield and higher carbon content, is an ideal carbon precursor for preparing high-performance electrode materials, and the preparation methods of the commonly used porous carbon-based materials usually comprise a hard template method, an activation method, a soft template method and the like. The direct activation method generally adopts KOH, NaOH and H₃PO₄When the activating agent is used for etching the precursor at high temperature, the requirement on the corrosion resistance of equipment is high, the yield of the product is low, and the product has a single pore passage and is mainly microporous and mesoporous. The soft template method has high requirements on the carbon precursor, generally requires that the carbon precursor and a surfactant or a block copolymer can be self-assembled, and has the limitations of higher production cost, complex preparation process and high requirements on the precursor on further popularization and application of the carbon precursor although the template is not required to be removed by adding an acidic reagent.

CN109321211A discloses a graphitized hierarchical porous carbon composite phase change energy storage material and a preparation method thereof, wherein a carbon precursor with low price, a graphitized catalyst and a pore-forming agent are used as raw materials, and the graphitized hierarchical porous carbon is prepared by ball-milling, mixing, carbonization and other processes; and compounding the prepared graphitized hierarchical porous carbon serving as a support material with a phase-change material to obtain the graphitized hierarchical porous carbon composite phase-change energy storage material.

CN106430144A discloses a method for preparing asphalt-based hierarchical porous carbon sheets by using sheet magnesium oxide templates and application thereof, wherein the method specifically comprises the following steps: and dropwise adding the asphalt solution into the magnesium oxide suspension, stirring, drying to obtain brown powder, carbonizing, grinding, adding potassium hydroxide, grinding, carbonizing for the second time, adding dilute hydrochloric acid into the product, ultrasonically oscillating, washing and drying to obtain the hierarchical porous carbon material.

CN109292750A discloses a preparation method of an inter-crosslinked three-dimensional porous carbon sheet for a supercapacitor, which is characterized by comprising the following steps: the preparation method comprises the steps of taking viscous petroleum asphalt as a carbon source and potassium citrate as a template agent, forming ester bond combination between carboxylic acid in the potassium citrate and hydroxyl in the petroleum asphalt through pyrolysis, cracking the ester bond to generate gas to form a bubbling structure, and further performing pyrolysis to prepare the nanosheet porous carbon material.

Therefore, the development of a method for improving the yield of the porous carbon and improving the pore canal singleness of the product is the focus of research in the field.

Disclosure of Invention

The invention aims to provide a preparation method of porous carbon, the porous carbon obtained by the preparation method and application of the porous carbon. The preparation method of the porous carbon further improves the yield of the obtained porous carbon product, and enables the porous carbon to have a rich mesoporous structure.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for preparing porous carbon, comprising the steps of: mixing petroleum asphalt with a template, calcining, and removing the residual template after calcining to obtain the porous carbon, wherein the template is basic magnesium carbonate and/or magnesium oxide.

The preparation method of the porous carbon further improves the yield of the obtained porous carbon product, and enables the porous carbon to have rich mesoporous structures, so that the porous carbon material prepared by the method has more excellent lithium storage capacity and higher specific capacity compared with graphite of a negative electrode of a commercial lithium ion battery/capacitor and activated carbon of a positive electrode of a commercial super capacitor/lithium ion capacitor, and can greatly improve the energy density and the cycling stability of the commercial lithium ion battery and the super capacitor.

Preferably, the mass ratio of the petroleum asphalt to the template is (3-5):1, such as 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, 5:1, and the like.

Preferably, the petroleum asphalt is a hard asphalt, the petroleum asphalt has an initial weight loss temperature of greater than 300 ℃ (e.g., 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, etc.), the petroleum asphalt has a weight loss of greater than 75% (e.g., 76%, 77%, 78%, 79%, 80%, etc.) between 300 ℃ and 635 ℃ (e.g., 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 635 ℃, etc.), and the petroleum asphalt has a weight loss of greater than 95% (e.g., 95%, 96%, 97%, 98%, 99%, etc.) at greater than 750 ℃ (e.g., 755 ℃, 760 ℃, 765 ℃, 770 ℃, 775 ℃, etc.).

Preferably, the basic magnesium carbonate is not pretreated, the initial weight loss stage is 34-300 ℃, and the weight loss ratio is 19.3 wt% due to moisture removal. The second weight loss stage was 300-. The total weight loss ratio of the two stages was 56.7 wt%.

Preferably, the calcination is carried out in a horizontal high temperature tube furnace.

Preferably, the temperature of the calcination is 700-.

Preferably, the removing of the template remaining after calcination specifically comprises: and washing with hydrochloric acid to remove the residual template after calcination.

Preferably, the hydrochloric acid is used in an amount of 10 to 150mL/g of asphalt, e.g., 10mL/g of asphalt, 20mL/g of asphalt, 40mL/g of asphalt, 60mL/g of asphalt, 80mL/g of asphalt, 100mL/g of asphalt, 120mL/g of asphalt, 140mL/g of asphalt, 150mL/g of asphalt, etc., and the hydrochloric acid has a concentration of 1 to 10mol/L, e.g., 1mol/L, 2mol/L, 4mol/L, 6mol/L, 8mol/L, 10mol/L, etc. Wherein, the dosage of the hydrochloric acid refers to the volume of the hydrochloric acid used per gram of the asphalt, for example, 10mL/g of the asphalt refers to that 10mL of the hydrochloric acid is used for washing and removing the residual template after calcination every 1g of the asphalt.

Preferably, the hydrochloric acid washing is followed by water washing, the number of the water washing is 1-2, and the amount of water is 500-1000mL/g asphalt, such as 500mL/g asphalt, 600mL/g asphalt, 700mL/g asphalt, 800mL/g asphalt, 900mL/g asphalt, 1000mL/g asphalt, etc. Where the amount of water used is the volume of water used per gram of bitumen, for example "500 mL/g bitumen" means that 500mL of water are required per 1g of bitumen for washing.

Preferably, the porous carbon is a two-dimensional porous carbon nanosheet, and the preparation method of the two-dimensional porous carbon nanosheet comprises the following steps:

(1) mixing the petroleum asphalt and the basic magnesium carbonate in a grinding and mixing mode;

(2) calcining the mixed substance obtained in the step (1) in a high-temperature tubular furnace in a nitrogen atmosphere;

(3) and (3) washing the product obtained by calcining in the step (2) with hydrochloric acid to remove the residual template after calcining, and then washing with water to obtain the two-dimensional porous carbon nanosheet.

Preferably, the porous carbon is a porous carbon having a three-dimensional hierarchical porous structure, and the preparation method of the porous carbon having the three-dimensional hierarchical porous structure comprises the following steps:

(1') mixing the petroleum asphalt and the magnesium oxide by a grinding mixing mode;

(2') calcining the mixed substance obtained in the step (1') in a high-temperature tubular furnace in a nitrogen atmosphere;

(3') washing the product obtained by calcining in the step (2') with hydrochloric acid to remove the residual template after calcining, and then washing with water to obtain intermediate porous carbon;

(4') mixing the intermediate porous carbon obtained in the step (3') with an activating agent by a grinding mixing mode;

(5') calcining the mixed substance obtained in the step (4') in a high-temperature tubular furnace in a nitrogen atmosphere;

(6) and (5') washing the product obtained by calcining in the step (5') with hydrochloric acid to remove the residual template after calcining, and then washing with water to obtain the porous carbon with the three-dimensional hierarchical porous structure.

Preferably, in step (4'), the activator is potassium hydroxide.

Preferably, in step (4'), the mass ratio of the activator to the intermediate porous carbon is (3-5):1, for example, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, 5:1, etc.

Preferably, in step (5'), the temperature of the calcination is 700-.

Preferably, in step (6'), the hydrochloric acid is used in an amount of 2 to 30mL/g of asphalt, for example, 2mL/g of asphalt, 4mL/g of asphalt, 6mL/g of asphalt, 8mL/g of asphalt, 10mL/g of asphalt, 12mL/g of asphalt, 14mL/g of asphalt, 16mL/g of asphalt, 18mL/g of asphalt, 20mL/g of asphalt, 22mL/g of asphalt, 24mL/g of asphalt, 26mL/g of asphalt, 28mL/g of asphalt, 30mL/g of asphalt, etc., and the hydrochloric acid has a concentration of 1 to 10mol/L, for example, 1mol/L, 2mol/L, 4mol/L, 6mol/L, 8mol/L, 10mol/L, etc.

Preferably, in step (6'), the number of washing with water is 1-2, and the amount of water used is 100-200mL/g of asphalt, such as 100mL/g of asphalt, 120mL/g of asphalt, 140mL/g of asphalt, 160mL/g of asphalt, 180mL/g of asphalt, 200mL/g of asphalt, etc.

In a second aspect, the present invention provides a porous carbon obtained by the method for producing a porous carbon according to the first aspect. Preferably, the porous carbon is a two-dimensional porous carbon nanosheet or a porous carbon having a three-dimensional hierarchical porous structure.

In a third aspect, the present invention provides the use of a porous carbon according to the second aspect for the preparation of a lithium ion capacitor.

In a fourth aspect, the invention provides a lithium ion electrode plate, which includes the porous carbon according to the second aspect. Preferably, the electrode sheet is a positive electrode sheet, and the electrode sheet is porous carbon as described in the second aspect. Preferably, the electrode plate is a negative electrode plate, and the preparation raw materials of the negative electrode plate comprise: the porous carbon, conductive agent and binder of the second aspect.

Preferably, the mass ratio of the porous carbon to the conductive agent to the binder is (6-8): 1-2;

wherein "6-8" is, for example, 6, 6.5, 7, 7.5, 8, etc., the first "1-2" is, for example, 1, 1.2, 1.4, 1.6, 1.8, 2, etc., and the second "1-2" is, for example, 1, 1.2, 1.4, 1.6, 1.8, 2, etc.

Preferably, the conductive agent is conductive carbon black.

Preferably, the binder is an aqueous solution of sodium carboxymethyl cellulose.

In a fifth aspect, the invention provides a lithium ion capacitor, which includes the lithium ion electrode plate described in the fourth aspect.

In the lithium ion capacitor, the mass ratio of the positive electrode tab to the negative electrode tab is preferably (1-3):1, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.2:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, and the like.

Compared with the prior art, the invention has the following beneficial effects:

(1) the raw material used in the invention is the hard petroleum asphalt which is a byproduct in the petroleum refining process, compared with the raw materials of the active carbon and the graphite which are industrially prepared, the price is low, the source is wide, the yield is high, the high carbon content ensures that the prepared porous carbon product has high yield, and the carbon precursor is a carbon precursor with low added value.

(2) The preparation method of the material used in the invention is simple to operate, the used chemical reagent is low in price, the production cost is greatly reduced, and the material has an objective large-scale application prospect.

(3) Compared with graphite of a negative electrode of a commercial lithium ion battery/capacitor and activated carbon of a positive electrode of a commercial super capacitor/lithium ion capacitor, the porous carbon material prepared by the method has more excellent lithium storage capacity, shows higher specific capacity, and can greatly improve the energy density and the cycling stability of the commercial lithium ion battery and the super capacitor.

(4) The two-dimensional porous carbon nanosheet and the three-dimensional hierarchical porous carbon prepared by the method can be respectively used as active materials of a negative electrode and a positive electrode of a lithium ion capacitor, and have ultrahigh specific capacity and outstanding cycling stability; the lithium ion capacitor assembled by the two materials has higher energy density and power density than commercial lithium ion capacitors, has good long-cycle stability, and has great popularization and application values.

Drawings

FIG. 1 is a scanning electron micrograph of HCNs-5 provided in example 1, with a scale of 1 μm.

FIG. 2 is a scanning electron micrograph of HCNs-5 provided in example 1 at 200 nm.

FIG. 3 is a TEM image of HCNs-5 provided in example 1, with a scale of 500 nm.

FIG. 4 is a TEM image of HCNs-5 provided in example 1, with a scale of 50 nm.

FIG. 5 is an X-ray diffraction (XRD) spectrum of HCNs-5 provided in example 1.

FIG. 6 is a Raman spectrum of HCNs-5 provided in example 1.

FIG. 7 is a scanning electron micrograph of HCNs-4 provided in example 2, with a scale of 1 μm.

FIG. 8 is a scanning electron micrograph of HCNs-4 provided in example 2 at 200 nm.

Figure 9 is an X-ray diffraction (XRD) spectrum of HCNs-4 provided in example 2.

FIG. 10 is a Raman spectrum of HCNs-4 provided in example 2.

FIG. 11 is a scanning electron micrograph of HCNs-6 provided in example 3, with a scale of 1 μm.

FIG. 12 is a scanning electron micrograph of HCNs-6 provided in example 3 at 200 nm.

FIG. 13 is an X-ray diffraction (XRD) spectrum of HCNs-6 provided in example 3.

FIG. 14 is a Raman spectrum of HCNs-6 provided in example 3.

FIG. 15 is a scanning electron micrograph of 3DHPC-5 provided in example 5 at 500 nm.

FIG. 16 is a scanning electron micrograph of 3DHPC-5 provided in example 5 at 100 nm.

FIG. 17 is a SEM of 3DHPC-5 provided in example 5, with a scale of 500 nm.

FIG. 18 is a TEM image of 3DHPC-5 provided in example 5, with a scale of 100 nm.

FIG. 19 is a scanning electron micrograph of basic magnesium carbonate with a scale of 1 μm.

FIG. 20 is a scanning electron micrograph of basic magnesium carbonate at 200 nm.

FIG. 21 is a scanning electron micrograph of magnesium oxide, with a scale of 2 μm.

FIG. 22 is a scanning electron micrograph of magnesium oxide at 500 nm.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The sources of the components in the following embodiments are as follows: petroleum asphalt is purchased from China petrochemical Jiujiang petrochemical company, brand: hard asphalt), basic magnesium carbonate is purchased from China pharmaceutical group chemical reagent limited, brand: 20023717, conductive carbon black is purchased from Dongguan city Korea laboratory instruments science limited, brand: MA-EN-CO-03, and sodium carboxymethylcellulose is purchased from Shanghai Allantin Biotechnology limited, brand: C104977.

Example 1

The embodiment provides a preparation method of porous carbon (HCNs-4), which comprises the following steps:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of basic magnesium carbonate, grinding and mixing uniformly in a 250mL agate mortar;

(2) transferring the corundum boat into a 20mL corundum boat, putting the corundum boat into a horizontal tube furnace filled with nitrogen, and heating the corundum boat from room temperature to 800 ℃ at the heating rate of 5 ℃/min and keeping the corundum boat for 120 min;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring a sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain a final product, namely HCNs-4.

Fig. 1 and 2 are scanning electron micrographs of HCNs-4 provided in example 1, and as shown in fig. 1 and 2, it can be seen from the scanning electron micrographs of HCNs-4 that the prepared material has a two-dimensional lamellar structure, and can provide an enlarged interlayer spacing for intercalation and diffusion of lithium ions, effectively reduce diffusion resistance of lithium ions, and improve transport kinetics of lithium ions. Meanwhile, the stable two-dimensional lamellar structure can effectively relieve the volume change caused in the process of lithium ion insertion and extraction, and the circulation stability of the material is improved.

FIGS. 3 and 4 are transmission electron micrographs of HCNs-4 provided in example 1, and from FIG. 3, it can be seen that the material HCNs-4 is a defect-rich layered structure capable of providing rich active sites and storage spaces for the adsorption and storage of lithium ions; as shown in fig. 4, it is shown that the two-dimensional lamellar surface has rich mesopores, which effectively increases the specific surface area of the material, further shortens the diffusion path of lithium ions, accelerates the transmission rate of lithium ions in the material bulk, provides rich space for the adsorption of lithium ions, increases the surface capacitance contribution ratio of lithium ions, shows fast reaction kinetics, and is an ideal high-performance negative electrode active material for a lithium ion capacitor.

FIG. 5 is an X-ray diffraction (XRD) spectrum of HCNs-4 provided in example 1, from which FIG. 5, a powder X-ray diffraction pattern of HCNs-4 showing two diffraction peaks corresponding to the 002 and 100 crystal planes of graphite at around 23 DEG and 43 DEG can be seen, indicating that the prepared example exhibits the characteristics of amorphous carbon.

FIG. 6 is a Raman spectrum of HCNs-4 provided in example 1, as shown in FIG. 6, which is seen to be located at 1350cm^-1And 1590cm^-1The two peaks correspond to the D peak (sp) of the carbon material²) And G peak (sp)³) Peak intensity ratio of D peak to G peak I_D/I_GThe higher defect degree of the embodiment is shown to be 0.894, which is beneficial to providing abundant electrochemical lithium storage active sites for the storage of lithium ions, greatly improving the lithium storage capacity of the material, and simultaneously increasing the capacitance contribution ratio of the material capacity.

Example 2

The embodiment provides a preparation method of porous carbon (HCNs-3), and the preparation method of the porous carbon (HCNs-3) comprises the following steps:

(1) respectively weighing 1.0g of petroleum asphalt and 3.0g of basic magnesium carbonate, grinding and mixing uniformly in a 250mL agate mortar;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring a sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain a final product, namely HCNs-3.

Fig. 7 and 8 are scanning electron micrographs of HCNs-3 provided in example 2, and as shown in fig. 7 and 8, it can be seen from the scanning electron micrographs of HCNs-3 that the prepared material has a blocky morphology, lacks of pores, has a small specific surface area, is not favorable for rapid transmission of lithium ions on the surface and bulk phase of the material, has a large transmission resistance, and simultaneously has a relatively limited effective lithium storage capacity, which greatly limits the lithium storage capacity of the material. The coating effect of the template is poor due to less template addition, and the regulation and activation effects of the template are not effectively exerted.

FIG. 9 is an X-ray diffraction (XRD) spectrum of HCNs-3 provided in example 2, and as shown in FIG. 9, two diffraction peaks corresponding to the 002 and 100 crystal planes of graphite at around 23 DEG and 43 DEG are observed in a powder X-ray diffraction pattern of HCNs-3, and amorphous carbon characteristics consistent with those of example 1 are exhibited.

Fig. 10 is a raman spectrum of HCNs-3 provided in example 2, and as shown in fig. 10, a raman spectrum of HCNs-3 shows that example 2 has similar spectral characteristics to example 1, i.e., shows defect peaks (D peaks) and graphitization peaks (G peaks) corresponding to carbon materials, and ID/IG is 0.895, and the defect degree is high.

Example 3

The embodiment provides a preparation method of porous carbon (HCNs-5), and the preparation method of the porous carbon (HCNs-5) comprises the following steps:

(1) respectively weighing 1.0g of petroleum asphalt and 5.0g of basic magnesium carbonate, grinding and mixing uniformly in a 250mL agate mortar;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring a sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain a final product, namely HCNs-5.

Fig. 11 and 12 are scanning electron micrographs of HCNs-5 provided in example 3, and as shown in fig. 11 and 12, it can be seen from the scanning electron micrographs of HCNs-5 that the prepared material has a lamellar stacking structure and is severely deficient in pore structure. The excessively high template addition amount causes deformation and convolution of the prepared lamellar structure, is not beneficial to the adsorption of lithium ions on the surface of the material and the insertion and extraction of the lithium ions in a bulk phase, and has short lithium storage space and weak lithium storage capacity.

FIG. 13 is an X-ray diffraction (XRD) spectrum of HCNs-5 provided in example 3; in the powder X-ray diffraction pattern of HCNs-5, two diffraction peaks corresponding to the 002 and 100 crystal planes of graphite, around 23 DEG and 43 DEG, were observed, exhibiting amorphous carbon characteristics consistent with those of example 1.

FIG. 14 is a Raman spectrum of HCNs-5 provided in example 3; the raman spectrum of HCNs-5 showed similar spectral characteristics of example 3 to example 1, i.e., exhibited defect peaks (D peaks) and graphitization peaks (G peaks) corresponding to carbon materials, with ID/IG of 0.859, and had the lowest defect level and the highest graphitization level as compared with examples 1 and 2. According to the electrochemical test results, the lithium storage capacity of this example was the worst, which is attributed to the lowest defect level and deformed two-dimensional lamellar structure.

Example 4

The present embodiment provides a method for preparing porous carbon (SHC-4), where the method for preparing porous carbon (SHC-4) includes the following steps:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of magnesium oxide, grinding and mixing uniformly in a 250mL agate mortar;

(2) then transferring the mixture into a 20mL corundum boat, putting the corundum boat into a horizontal tube furnace filled with nitrogen, heating the mixture from room temperature to 800 ℃ at the heating rate of 5 ℃/min, and keeping the temperature for 120 min;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration into a 60 ℃ drying oven for drying for 120min to obtain the final product, namely SHC-4.

Example 5

The present embodiment provides a method for preparing porous carbon (3DHPC-4), where the method for preparing porous carbon (3DHPC-4) includes the following steps:

(1) respectively weighing 0.1g of the SHC-5 prepared in example 4 and 0.4g of KOH, and grinding and uniformly mixing in a 250mL agate mortar;

(3) and (3) reducing the temperature of the isopipe furnace to room temperature, transferring the calcined product to a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual KOH after calcination, washing for many times, transferring the sample obtained by vacuum filtration to a 60 ℃ oven for drying for 24 hours to obtain the final product, namely 3 DHPC-4.

Comparative example 1

The present comparative example provides a method for preparing porous carbon (HPC-4), the method for preparing porous carbon (HPC-4) comprising the steps of:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of potassium citrate, grinding in a 250mL agate mortar, and uniformly mixing;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain the final product, namely the HPC-4.

Comparative example 2

The present comparative example provides a method of preparing porous carbon (MCC-4), the method of preparing porous carbon (MCC-4) comprising the steps of:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of magnesium citrate, grinding in a 250mL agate mortar, and uniformly mixing;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring a sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain a final product, namely MCC-4.

Comparative example 3

The present comparative example provides a method for producing porous carbon (MAC-4), the method for producing porous carbon (MAC-4) including the steps of:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of magnesium acetate, grinding and mixing uniformly in a 250mL agate mortar;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain the final product, namely MAC-4.

Comparative example 4

The present comparative example provides a method for preparing porous carbon (PAC-4), the method for preparing porous carbon (PAC-4) comprising the steps of:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of potassium acetate, grinding and mixing uniformly in a 250mL agate mortar;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain the final product, namely PAC-4.

Comparative example 5

The present comparative example provides a method for producing porous carbon (IOC-4), the method for producing porous carbon (IOC-4) including the steps of:

(1) respectively weighing 1.0g of petroleum asphalt and 4.0g of ferric oxide, grinding and mixing uniformly in a 250mL agate mortar;

(3) and when the temperature of the tube furnace is reduced to room temperature, transferring the calcined product into a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration into a 60 ℃ oven for drying for 24 hours to obtain the final product, namely IOC-4.

Comparative example 6

The present comparative example provides a method for producing porous carbon (HPAC-4), the method for producing porous carbon (HPAC-4) comprising the steps of:

(1) 0.1g of HPC-4 prepared in comparative example 1 and 0.4g of KOH are weighed respectively and ground and mixed evenly in a 250mL agate mortar;

(3) and (3) reducing the temperature of the isopipe furnace to room temperature, transferring the calcined product to a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration to a 60 ℃ oven for drying for 24 hours to obtain the final product, namely HPAC-4.

Comparative example 7

The present comparative example provides a method for producing porous carbon (MCAC-4), the method for producing porous carbon (MCAC-4) including the steps of:

(1) respectively weighing 0.1g of MCC-4 prepared in the comparative example 2 and 0.4g of KOH, and grinding and mixing the mixture uniformly in a 250mL agate mortar;

(3) and (3) reducing the temperature of the isopipe furnace to room temperature, transferring the calcined product to a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration to a 60 ℃ oven for drying for 120min to obtain the final product, namely MCAC-5.

Comparative example 8

The present comparative example provides a method for producing porous carbon (MAAC-4), the method for producing porous carbon (MAAC-4) including the steps of:

(1) respectively weighing 0.1g of the MAC-4 prepared in the comparative example 3 and 0.4g of KOH, and grinding and mixing the mixture uniformly in a 250mL agate mortar;

(3) and (3) reducing the temperature of the isopipe furnace to room temperature, transferring the calcined product to a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration to a 60 ℃ oven for drying for 24 hours to obtain the final product, namely MAAC-4.

Comparative example 9

The present comparative example provides a method for producing porous carbon (HACNs-4), the method for producing porous carbon (HACNs-4) including the steps of:

(1) respectively weighing 0.1g of HCNs-4 prepared in example 1 and 0.4g of KOH, and grinding and uniformly mixing in a 250mL agate mortar;

(3) and (3) reducing the temperature of the isopipe furnace to room temperature, transferring the calcined product to a 250mL beaker, adding a proper amount of hydrochloric acid to remove the residual template after calcination, washing for many times, and transferring the sample obtained by vacuum filtration to a 60 ℃ oven for drying for 24 hours to obtain the final product, namely HACNs-4.

Application example 1

The embodiment provides a metal ion capacitor, wherein a capacitor cathode electrode material comprises the following components: 32mg of HCNs-4 active material, 6mg of conductive carbon black, and an aqueous solution containing 2mg of sodium carboxymethylcellulose from example 1.

The present embodiment provides a method for manufacturing a secondary battery, including the steps of:

32mg of HCNs-4 active material, 6mg of conductive carbon black and an aqueous solution containing 2mg of sodium carboxymethylcellulose. Fully grinding and uniformly mixing the mixture in a 100mL mortar, coating the mixture on a copper foil, and controlling the electrode area loading on the copper foil to be 1.0mg/cm²And then transferring the obtained product to a vacuum oven to dry the product at the temperature of 80 ℃ for 120min, and then cutting the product into round electrode plates and assembling the electrode plates and metal lithium plates into button secondary batteries.

Application example 2

The present application example provides a metal ion capacitor, which is different from application example 1 only in that HCNs-3 provided in example 2 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the method for producing the battery are the same as in application example 1.

Application example 3

The present application example provides a metal ion capacitor, which is different from application example 1 only in that HCNs-5 provided in example 3 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the method for producing the battery are the same as in application example 1.

Application example 4

The present application example provides a metal ion capacitor, which is different from application example 1 only in that the capacitor negative electrode material contains the SHC-4 provided in example 4, and the amounts of the remaining raw materials and the method for producing the battery are the same as in application example 1.

Application example 5

The embodiment provides a metal ion capacitor, wherein a positive electrode material of the capacitor comprises the following components: 32mg of 3DHPC-4 active material from example 4, 6mg of conductive carbon black and an aqueous solution containing 2mg of sodium carboxymethylcellulose.

A method for manufacturing a secondary battery, comprising the steps of:

fully grinding 32mg of 3DHPC-4 active material, 4mg of conductive carbon black and an aqueous solution containing 2mg of sodium carboxymethylcellulose in a 100mL mortar, uniformly mixing, coating on an aluminum foil, and controlling the electrode area loading on the aluminum foil to be 2.0mg/cm²And then transferring the obtained product to a vacuum oven to dry the product at the temperature of 80 ℃ for 120min, and then cutting the product into round electrode plates and assembling the electrode plates and metal lithium plates into button secondary batteries.

Application example 6

This example provides a metal ion capacitor, where the negative electrode tab is the electrode tab prepared in example 1, and the positive electrode tab is the electrode tab prepared in application example 5. And the mass ratio of the negative electrode plate to the positive electrode plate is 1:1, and the pre-lithiated negative electrode plate and the positive electrode plate are assembled into a complete lithium ion capacitor.

Application example 7

This example provides a metal ion capacitor, where the negative electrode tab is the electrode tab prepared in example 1, and the positive electrode tab is the electrode tab prepared in application example 5. And the mass ratio of the negative electrode plate to the positive electrode plate is 1:2, and the pre-lithiated negative electrode plate and the positive electrode plate are assembled into a complete lithium ion capacitor.

Application example 8

This example provides a metal ion capacitor, where the negative electrode tab is the electrode tab prepared in example 1, and the positive electrode tab is the electrode tab prepared in application example 5. And the mass ratio of the negative electrode plate to the positive electrode plate is 1:3, and the pre-lithiated negative electrode plate and the positive electrode plate are assembled into a complete lithium ion capacitor.

Comparative application example 1

This comparative application example provides a metal ion capacitor, which is different from application example 1 only in that HPC-4 provided in comparative example 1 is contained in the capacitor negative electrode material, and the remaining raw material amounts and the battery preparation method are the same as in application example 1.

Comparative application example 2

The comparative application example provides a metal ion capacitor, which is different from application example 1 only in that the MCC-4 provided in comparative example 2 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the preparation method of the battery are the same as in application example 1.

Comparative application example 3

This comparative application example provides a metal ion capacitor, which is different from application example 1 only in that the MAC-4 provided in comparative example 3 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the method of producing the battery are the same as in application example 1.

Comparative application example 4

This comparative application example provides a metal ion capacitor, which is different from application example 1 only in that PAC-4 provided in comparative example 4 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the method of manufacturing the battery are the same as in application example 1.

Comparative application example 5

This comparative application example provides a metal ion capacitor, which is different from application example 1 only in that IOC-4 provided in comparative example 5 is contained in the capacitor negative electrode material, and the amounts of the remaining raw materials and the method of producing the battery are the same as in application example 1.

Comparative application example 6

This comparative application example provides a metal ion capacitor, which is different from application example 5 only in that HPAC-4 provided in comparative example 6 is contained in the positive electrode material of the capacitor, and the amounts of the remaining raw materials and the method of manufacturing the battery are the same as those of application example 5.

Comparative application example 7

This comparative application example provides a metal ion capacitor, differing from application example 5 only in that MCAC-4 provided in comparative example 7 was contained in the capacitor positive electrode material, and the amounts of the remaining raw materials and the method of producing the battery were the same as in application example 5.

Comparative application example 8

This comparative application example provides a metal ion capacitor, which is different from application example 5 only in that MAAC-4 provided in comparative example 8 is contained in the positive electrode material of the capacitor, and the amounts of the remaining raw materials and the method for producing the battery are the same as in application example 5.

Comparative application example 9

The present comparative application example provides a metal ion capacitor, which is different from application example 5 only in that HACNs-4 provided in comparative example 9 is contained in the positive electrode material of the capacitor, and the amounts of the remaining raw materials and the method of producing the battery are the same as in application example 5.

Performance testing

The secondary batteries and the metal ion capacitors provided in the application examples 1 to 8 and the comparative application examples 1 to 9 were subjected to various electrochemical lithium storage performance tests, and the specific test methods were as follows:

(1) lithium storage performance: and testing the lithium storage performance of the anode or the cathode: performing lithium storage performance test on a blue test device, wherein the voltage range of a negative electrode test is 0.01-3.0V, and the current density of the test is 1 Ag-1; the voltage range of the anode test is 2.0-4.5V, and the current density of the anode test is 2 Ag-1; testing the quality of the obtained lithium storage specific capacity based on the single-electrode active substance;

(2) testing the lithium storage performance of the lithium ion capacitor:

firstly, a constant current charge and discharge test is carried out on an electrochemical workstation at Shanghai under different current densities, namely: 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0Ag-1, the voltage range of the test is 0.5-4.2V, the discharge time Deltat/s under different current densities is recorded, and the energy density (E) and the power density (P) of the metal ion capacitor are calculated according to the following formulas: p ═ I × (Vmax + Vmin) × 1000]/(m × 2); e ═ P × Δ t)/3600, where: i/m is current density with the unit of Ag-1; (Vmax + Vmin)/2 is the average voltage in V; Δ t is the discharge time in units of s. Secondly, testing the cycling stability in a blue test device, wherein the tested voltage range is 0.5-4.2V, the tested current density is 1Ag < -1 >, and the tested specific capacity of the lithium storage is based on the total mass of the active materials of the anode and the cathode.

The specific test results are shown in tables 1-3 below:

TABLE 1

As can be seen from table 1, the two-dimensional porous carbon nanosheet with rich mesopores prepared by the method disclosed by the invention has excellent lithium storage performance, and HCNs-5 prepared in example 1 shows the most excellent lithium storage capacity of the negative electrode, so that the lithium storage performance of the negative electrode is significantly improved compared with that of a commercial graphite negative electrode.

TABLE 2

As can be seen from table 2, the porous carbon with a three-dimensional hierarchical skeleton prepared by the present invention has excellent lithium storage performance, and the 3DHPC-5 prepared in example 4 exhibits the most excellent lithium storage capacity of the positive electrode, and has significantly improved lithium storage performance compared to the lithium storage performance of a commercial activated carbon positive electrode.

TABLE 3

By comparing the lithium storage performance of the negative electrode and the positive electrode of the application example, HCNs-4 is adopted as the negative electrode, 3DHPC-4 is adopted as the positive electrode active material, the dual-carbon mixed lithium ion capacitor HCNs-4/3 DHPC-4 is constructed, the different mass ratios of the positive electrode and the negative electrode are researched, and the lithium ion capacitor constructed when the mass ratios of the positive electrode and the negative electrode are the same has the optimal electrochemical performance.

Fig. 19 and 20 are scanning electron microscope images of basic magnesium carbonate, and as shown in fig. 19 and 20, the basic magnesium carbonate shows an irregular stacking lamellar morphology, so that petroleum asphalt can obtain a porous nanosheet morphology with a high specific surface area. Among them, fig. 21 and 20 are scanning electron micrographs of magnesium oxide, and as shown in fig. 21 and 22, they show a dispersed bulk morphology, and can make petroleum pitch have a porous morphology, increase the specific surface area of the material, and shorten the diffusion distance of electrolyte ions.

The applicant states that the present invention is illustrated by the above examples of the preparation method of the porous carbon of the present invention and the porous carbon obtained therefrom and the applications thereof, but the present invention is not limited to the above process steps, i.e. it is not meant that the present invention must rely on the above process steps to be carried out. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims

1. A preparation method of porous carbon is characterized by comprising the following steps: mixing petroleum asphalt with a template, calcining, and removing the residual template after calcining to obtain the porous carbon, wherein the template is basic magnesium carbonate and/or magnesium oxide.

2. The preparation method of porous carbon according to claim 1, wherein the mass ratio of the petroleum pitch to the template is (3-5): 1;

preferably, the petroleum asphalt is hard asphalt, the initial weight loss temperature of the petroleum asphalt is greater than 300 ℃, the weight loss of the petroleum asphalt is greater than 75 wt% between 300 ℃ and 635 ℃, and the weight loss of the petroleum asphalt is more than 95 wt% at the temperature of greater than 750 ℃.

3. The method for producing porous carbon according to claim 1 or 2, characterized in that the calcination is performed in a horizontal high-temperature tube furnace;

preferably, the calcination temperature is 700-900 ℃, the temperature rise rate of the calcination is 2-5 ℃/min, and the calcination time is 200-510 min.

4. The method for preparing porous carbon according to any one of claims 1 to 3, wherein the removal of the template remaining after calcination is specifically: washing with hydrochloric acid to remove the residual template after calcination;

preferably, the dosage of the hydrochloric acid is 10-150mL/g of asphalt, and the concentration of the hydrochloric acid is 1-10 mol/L;

preferably, the hydrochloric acid washing is followed by water washing, the number of times of water washing is 1-2, and the amount of water is 500-1000mL/g asphalt.

5. The preparation method of porous carbon according to any one of claims 1 to 4, characterized in that the porous carbon is a two-dimensional porous carbon nanosheet, the preparation method of the two-dimensional porous carbon nanosheet comprising the steps of:

6. The preparation method of porous carbon according to any one of claims 1 to 5, characterized in that the porous carbon is porous carbon having a three-dimensional hierarchical porous structure, the preparation method of porous carbon having a three-dimensional hierarchical porous structure comprising the steps of:

(6) washing the product obtained by calcining in the step (5') with hydrochloric acid to remove the residual template after calcining, and then washing with water to obtain porous carbon with a three-dimensional hierarchical porous structure;

preferably, in step (4'), the activator is potassium hydroxide;

preferably, in the step (4'), the mass ratio of the activator to the intermediate porous carbon is (3-5): 1;

preferably, in the step (5'), the calcination temperature is 700-;

preferably, in the step (6'), the dosage of the hydrochloric acid is 2-30mL/g of the asphalt, and the concentration of the hydrochloric acid is 1-10 mol/L;

preferably, in step (6'), the number of washing with water is 1-2, and the amount of water used is 100-200mL/g of asphalt.

7. Porous carbon, characterized in that it is obtained by a method for preparing porous carbon according to any one of claims 1 to 6;

preferably, the porous carbon is a two-dimensional porous carbon nanosheet or a porous carbon having a three-dimensional hierarchical porous structure.

8. Use of porous carbon according to claim 7 in the preparation of a lithium ion capacitor.

9. A lithium ion electrode sheet, wherein the lithium ion electrode sheet comprises the porous carbon of claim 7;

preferably, the electrode sheet is a positive electrode sheet, and the electrode sheet is porous carbon according to claim 7;

preferably, the electrode plate is a negative electrode plate, and the preparation raw materials of the negative electrode plate comprise: the porous carbon, conductive agent and binder of claim 7;

preferably, the conductive agent is conductive carbon black;

10. A lithium ion capacitor, characterized in that it comprises a lithium ion electrode sheet according to claim 9;

in the lithium ion capacitor, the mass ratio of the positive electrode sheet to the negative electrode sheet is preferably (1-3): 1.