Electrode material, preparation method thereof, supercapacitor and application thereof

Abstract

The application provides an electrode material, a preparation method thereof, a supercapacitor and application. The preparation method of the electrode material comprises the following steps: mixing a block copolymer, a metal complex and an organic chelating agent in an organic solvent, and performing a self-assembly reaction to form an ordered self-assembly precursor; mixing the ordered self-assembly precursor, a polymerization monomer and an initiator, and performing in-situ oxidative polymerization to obtain an ordered polymer / metal composite precursor; performing gradient pyrolysis on the ordered polymer / metal composite precursor in a protective atmosphere; and performing acid pickling treatment, filtration, washing and drying on the pyrolysis product to obtain the electrode material. The electrode material provided by the application has a regular cubic morphology, a large specific surface area, and a multi-level pore structure formed in the interior, can realize more efficient material transmission, and exhibits excellent performance in the fields of energy storage and conversion.

Description

An electrode material, its preparation method, and its application in supercapacitors. Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to an electrode material, its preparation method, and a supercapacitor and its applications. Background Technology

[0002] Porous carbon materials, due to their large specific surface area, excellent electrical conductivity, chemical stability, and tunable structure, have broad application prospects in energy storage and conversion, catalysis, and adsorption separation. In recent years, the development of high-performance porous carbon materials for clean energy storage and conversion and environmental remediation has become a research hotspot in the field of materials science.

[0003] Currently, the main methods for preparing porous carbon materials include physical activation, chemical activation, and template methods. Physical activation involves using oxidants such as CO2 and water vapor to react with carbon precursors at high temperatures to form a porous structure. Chemical activation involves using chemical reagents such as KOH, ZnCl2, and H3PO4 to react with carbon precursors at high temperatures to form pores. Template methods involve using solid templates (such as silica, metal oxides, and polymer microspheres) as a framework, infiltrating and carbonizing the carbon source, and then removing the template to obtain the porous carbon material.

[0004] However, these methods often struggle to simultaneously and precisely control both the external morphology and internal pore structure of carbon materials, especially in preparing porous carbon materials with regular geometries, which remains a significant challenge. The existing technologies suffer from the following shortcomings:

[0005] 1. Although porous carbon materials prepared by traditional activation methods have high specific surface areas, their pore size distribution is narrow, mainly consisting of micropores, which is not conducive to the transport of macromolecules and the efficient utilization of internal space. Moreover, the activation process is often accompanied by severe carbon loss, resulting in low yields, and the residue of activating agents can affect the purity and performance of the materials.

[0006] 2. Porous carbon materials prepared by conventional template methods often exhibit disordered morphologies and are difficult to form regular geometric shapes, especially cubic morphologies. Template methods typically require strict control of reaction conditions, and the template removal process is complex. The use of strong acids or bases can pollute the environment and may also damage the structural integrity of the carbon material.

[0007] 3. Existing porous carbon materials prepared based on soft templates can achieve ordered pore structures, but it is difficult to control the external morphology and the pore structure is monotonous, which cannot meet the needs of multi-scale material transport.

[0008] 4. The reported methods for controlling the morphology of porous carbon materials usually require complex templates or multi-step processes, which are complicated, costly, and difficult to mass-produce.

[0009] 5. The pore structures of most existing porous carbon materials are single-pore types or non-connected channels, which limits their application performance in fields such as electrochemistry. In particular, applications such as supercapacitors and lithium-sulfur batteries require well-developed hierarchical pore structures for rapid ion transport in the electrolyte and effective adsorption of macromolecules, which current technologies struggle to meet simultaneously.

[0010] In the field of electrochemical energy storage, porous carbon materials are commonly used as electrode materials in devices such as supercapacitors and lithium-sulfur batteries. An ideal electrode material should simultaneously possess a large specific surface area (providing abundant active sites), a well-developed hierarchical pore structure (facilitating ion transport), good conductivity (reducing internal resistance), and mechanical stability (ensuring cycle life). However, porous carbon materials prepared using existing technologies often struggle to simultaneously meet these requirements, especially at high current densities where limited ion transport leads to a sharp decline in electrochemical performance.

[0011] In the field of catalysis, porous carbon materials are often used as catalyst supports, requiring good dispersibility and stability, as well as a suitable pore structure to facilitate the transport of reactants and products. The irregular morphology and uneven pore distribution of existing porous carbon materials often lead to uneven catalyst dispersion and limited catalytic performance.

[0012] In the field of adsorption separation, porous carbon materials need to possess the ability to selectively adsorb specific molecules, which requires the material to have a precisely controllable pore size distribution and surface chemical properties. Current technologies struggle to precisely control pore structure and surface properties, limiting the application of porous carbon materials in highly selective separation processes.

[0013] Therefore, developing a simple, efficient, and highly controllable method to prepare carbon materials with regular morphology and multi-level interconnected pore structures is of great significance for expanding the application fields of porous carbon materials and improving their application performance. Summary of the Invention

[0014] To overcome the above problems, the present invention aims to provide an electrode material, a method for preparing the same, a supercapacitor, and its applications. This electrode material has a regular cubic morphology and a well-developed and interconnected hierarchical porous structure.

[0015] To achieve the above objectives, the present invention provides a method for preparing an electrode material, the method comprising:

[0016] S1. A block copolymer, a metal complex, and an organic chelating agent in a mass ratio of 1:(0.5-2):(0.5-3) are mixed in an organic solvent to form a first system, wherein the mass of the organic solvent is 30-100 times the mass of the block copolymer. The first system is subjected to a self-assembly reaction at 60-100°C for 6-24 hours to form an ordered self-assembled precursor.

[0017] S2. The ordered self-assembled precursor is mixed with polymeric monomers and initiators to form a second system, wherein the mass of the polymeric monomers is 0.5-2 times the mass of the block copolymer, and an in-situ oxidative polymerization reaction is carried out to obtain an ordered polymer / metal composite precursor.

[0018] S3. Under a protective atmosphere, the ordered polymer / metal composite precursor is subjected to gradient pyrolysis to obtain a cubic carbon / metal composite material.

[0019] S4. The cubic carbon / metal composite material is added to an acidic oxidant for pickling treatment, wherein the acidic oxidant includes a mixed solution of strong acid and hydrogen peroxide; the mixture is filtered, washed, and dried to obtain the electrode material.

[0020] According to a specific embodiment of the present invention, the block copolymer includes one or more combinations of polystyrene-polyvinylpyrrolidone, polystyrene-polyethylene glycol, polystyrene-polyacrylic acid, and polystyrene-polyvinylpyrrolidone-polyethylene glycol.

[0021] According to a specific embodiment of the present invention, the number-average molecular weight of the block copolymer is 20,000-50,000.

[0022] According to a specific embodiment of the present invention, the metal complex comprises a combination of two or more of the following: transition metal acetylacetonates, transition metal carboxylates, and transition metal carbamates. The transition metal comprises one or more of the following: Fe, Co, Ni, Cu, and Zn.

[0023] According to a specific embodiment of the present invention, the average particle size of the metal complex is 50-500 nm;

[0024] According to a specific embodiment of the present invention, the organic chelating agent includes one or a combination of two or more of citric acid, tartaric acid, ethylenediaminetetraacetic acid, diethyltriaminepentaacetic acid, trisodium citrate, disodium ethylenediaminetetraacetic acid, and potassium sodium tartrate.

[0025] According to a specific embodiment of the present invention, the organic solvent includes one or a combination of two or more of N,N-dimethylformamide, tetrahydrofuran, and dimethyl sulfoxide.

[0026] According to a specific embodiment of the present invention, the polymeric monomer includes one or more of pyrrole, aniline, thiophene, derivatives of pyrrole, derivatives of aniline, and derivatives of thiophene.

[0027] According to a specific embodiment of the present invention, the initiator includes one or a combination of two or more of ammonium persulfate, potassium persulfate, and hydrogen peroxide.

[0028] According to a specific embodiment of the present invention, the mass of the initiator is 0.1-0.3 times the mass of the polymer monomer.

[0029] According to a specific embodiment of the present invention, the temperature of the in-situ oxidative polymerization reaction is 20-50°C, and the time of the in-situ oxidative polymerization reaction is 4-12 hours.

[0030] According to a specific embodiment of the present invention, the gradient pyrolysis process includes: heating to 300-500℃ at a heating rate of 2-10℃ / min and holding at that temperature for 1-3 hours, and then heating to 700-1000℃ at a heating rate of 3-8℃ / min and holding at that temperature for 2-5 hours.

[0031] According to a specific embodiment of the present invention, the mass of the acidic oxidant is 20-50 times the mass of the cubic carbon / metal composite material.

[0032] According to a specific embodiment of the present invention, the pickling temperature is 60-90℃ and the pickling time is 5-15h.

[0033] According to a specific embodiment of the present invention, the preparation method further includes S5: surface modification of the dried product of S4 to introduce heteroatoms, thereby obtaining a surface-modified electrode material.

[0034] According to a specific embodiment of the present invention, the surface modification process is as follows: the dried product of S4 is subjected to plasma treatment in a low-temperature plasma.

[0035] According to a specific embodiment of the present invention, the power of the plasma treatment is 50-200W, and the time is 5-30min.

[0036] According to a specific embodiment of the present invention, the low-temperature plasma includes one or more combinations of plasmas containing the following gases: oxygen-containing gas, nitrogen-containing gas, sulfur-containing gas, and phosphorus-containing gas.

[0037] The present invention also provides an electrode material, which is obtained by the above-described electrode material preparation method.

[0038] According to a specific embodiment of the present invention, the electrode material comprises three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon.

[0039] According to a specific embodiment of the present invention, the electrode material has a cubic microstructure with a side length of 1-30 μm.

[0040] According to a specific embodiment of the present invention, the electrode material has a hierarchical porous structure, including micropores, mesopores, and macropores.

[0041] According to a specific embodiment of the present invention, the specific surface area of ​​the electrode material is 1200-3500 m². 2 / g, the porosity of the electrode material is 65-95%.

[0042] According to a specific embodiment of the present invention, the pore size of the electrode material is 1-90 nm.

[0043] According to a specific embodiment of the present invention, the electrode material contains more than 95% carbon by mass and less than 5% heteroatoms by mass.

[0044] According to a specific embodiment of the present invention, the heteroatom includes one or more combinations of nitrogen, sulfur, phosphorus, and oxygen.

[0045] According to a specific embodiment of the present invention, in the electrode material, the pore volume of the micropores accounts for 50-80% of the total pore volume, the pore volume of the mesopores accounts for 10-40% of the total pore volume, and the pore volume of the macropores accounts for 5-30% of the total pore volume.

[0046] The present invention also provides a supercapacitor, wherein the electrode material of the supercapacitor comprises the electrode material provided by the present invention.

[0047] According to a specific embodiment of the present invention, the electrolyte of the supercapacitor includes one of sulfuric acid solution, potassium hydroxide solution, and organic electrolyte.

[0048] This invention also provides the application of the above-mentioned electrode materials in the preparation of catalyst supports, electrocatalysts, biosensors, gas adsorption and separation materials, and water treatment adsorption materials.

[0049] The beneficial effects of this invention include:

[0050] 1. The electrode material provided by this invention has a regular cubic morphology, a large specific surface area, and a well-developed hierarchical porous structure. This electrode material, through its regular morphology and hierarchical porous structure, enables more efficient mass transport and exhibits excellent performance in energy storage and conversion, catalysis, adsorption and separation, and other fields.

[0051] 2. The electrode material preparation method provided by the present invention achieves simultaneous regulation of cubic morphology and internal hierarchical pore structure by precisely controlling the self-assembly process and pyrolysis conditions. The prepared electrode material has excellent electrochemical performance and mechanical stability and can be widely used in supercapacitors, lithium-sulfur batteries, catalysis, adsorption separation and other fields. Attached Figure Description

[0052] Figure 1 is a scanning electron microscope image of the cubic carbon / metal composite material prepared in Example 1.

[0053] Figure 2 is a scanning electron microscope image of the electrode material prepared in Example 1.

[0054] Figure 3 is a high-magnification scanning electron microscope image of the electrode material prepared in Example 1.

[0055] Figure 4 is a transmission electron microscope image of the electrode material prepared in Example 1.

[0056] Figure 5 shows the pore distribution curve of the electrode material prepared in Example 1.

[0057] Figure 6 shows the cyclic voltammetry curves of the supercapacitor prepared in Example 1.

[0058] Figure 7 shows the rate performance curve of the supercapacitor prepared in Example 1.

[0059] Figure 8 shows the cycle performance curve of the supercapacitor prepared in Example 1. Detailed Implementation

[0060] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0061] According to a specific embodiment of the present invention, the present invention provides a method for preparing an electrode material, the method comprising:

[0062] S1. A block copolymer, a metal complex, and an organic chelating agent in a mass ratio of 1:(0.5-2):(0.5-3) are mixed in an organic solvent to form a first system, wherein the mass of the organic solvent is 30-100 times the mass of the block copolymer. The first system is subjected to a self-assembly reaction at 60-100°C for 6-24 hours to form an ordered self-assembled precursor.

[0063] S2. The ordered self-assembled precursor is mixed with polymeric monomers and initiators to form a second system, wherein the mass of the polymeric monomers is 0.5-2 times the mass of the block copolymer, and an in-situ oxidative polymerization reaction is carried out to obtain an ordered polymer / metal composite precursor.

[0064] S3. Under a protective atmosphere, the ordered polymer / metal composite precursor is subjected to gradient pyrolysis to obtain a cubic carbon / metal composite material.

[0065] S4. The cubic carbon / metal composite material is added to an acidic oxidant for pickling treatment, wherein the acidic oxidant includes a mixed solution of strong acid and hydrogen peroxide; the mixture is filtered, washed, and dried to obtain the electrode material.

[0066] In the above preparation method, S1 forms a self-assembled precursor through a self-assembly reaction, which can serve as a template for the subsequent synthesis of cubic carbon materials; S2 mixes the self-assembled precursor with a carbon source to form a composite precursor that retains the structure of the self-assembled precursor; S3 removes the template agent through gradient pyrolysis and forms a well-developed hierarchical porous structure; S4 removes impurities by acid washing to obtain the electrode material. In some specific embodiments, the electrode material can be a three-dimensional cubic porous carbon material.

[0067] In the above preparation method, S1 can form a self-assembled precursor with an ordered structure, wherein the block copolymer provides a long-range ordered periodic structure at the nanoscale (nanoscale order), and the metal complex forms a nanoscale ordered distribution or cluster within the framework of the block copolymer (nanoscale order). The addition of the organic chelating agent not only helps to dissolve and disperse the metal precursor (metal complex), but also promotes the formation of a stronger metal-organic chelating agent-block polymer ternary coordination structure. This ternary coordination structure can significantly improve the stability and dispersibility of metal species in the polymer matrix and prevent agglomeration during high-temperature processing.

[0068] In the above preparation method, S1 enables the interconnection of reactant molecules (block copolymers, metal complexes, and organic chelating agents) through molecular self-assembly reactions, and a grafting reaction occurs. In some specific embodiments, in S1, the active functional groups (-COOH, -NH2, etc.) of the organic chelating agent are grafted to specific reaction sites (such as terminal hydroxyl groups and side-chain carboxyl groups) of the block copolymer in the form of covalent bonds, and the metal is integrated into the grafted organic chelating agent through coordination bonds.

[0069] In some specific embodiments, the self-assembled precursor obtained in S1 can have an ordered structure. Furthermore, the self-assembled precursor can have a cubic-like morphology, which can serve as a template for synthesizing cubic carbon materials.

[0070] In the above preparation method, in S1, the mass ratio of the block copolymer to the metal complex can be 1:(0.5-2), specifically 1:0.5, 1:1, 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, etc., and a range with any two of the above specific values ​​as endpoints, for example, 1:1-1.5.

[0071] In the above preparation method, in S1, the mass ratio of the block copolymer to the organic chelating agent can be 1:(0.5-3), specifically 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc., and a range with any two of the above specific values ​​as endpoints, for example, 1:0.5-0.8.

[0072] In the above preparation method, in S1, the mass of the organic solvent is 30-100 times the mass of the block copolymer, specifically 30, 40, 50, 60, 70, 80, 90, 100 times, etc., and a range with any two of the above specific values ​​as endpoints, for example, 65-100 times.

[0073] In the above preparation method, in S1, the block copolymer includes one or more of polystyrene-polyvinylpyrrolidone (PS-PVP), polystyrene-polyethylene glycol (PS-PEG), polystyrene-polyacrylic acid (PS-PAA), and polystyrene-polyvinylpyrrolidone-polyethylene glycol (PS-PVP-PEG).

[0074] In the above preparation method, in S1, the number average molecular weight of the block copolymer is 20,000-50,000, for example, specific values ​​such as 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, etc., and a range with any two of the above specific values ​​as endpoints.

[0075] In the above preparation method, in S1, the metal complex includes one or more of the following: acetylacetone salts of transition metals, carboxylates of transition metals, and carbamates of transition metals; the transition metal includes one or more of the following: Fe, Co, Ni, Cu, and Zn.

[0076] In the above preparation method, in S1, the average particle size of the metal complex is 50-500 nm, for example, specific values ​​such as 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc., and a range with any two of the above specific values ​​as endpoints; further, it can be 100-300 nm.

[0077] In the above preparation method, in step S1, the organic chelating agent includes one or more combinations of citric acid, tartaric acid, ethylenediaminetetraacetic acid (EDTA), diethyltriaminepentaacetic acid (DTPA), trisodium citrate, disodium ethylenediaminetetraacetic acid, and potassium sodium tartrate. In some specific embodiments, the purity of the organic chelating agent is ≥98%.

[0078] In the above preparation method, in S1, by controlling the amount of organic solvent relative to the block copolymer, it is helpful for the self-assembly process to form an ordered structure, obtain a regular and tightly ordered micelle structure, and ensure that the carbon material has a uniform pore structure, thereby obtaining a porous carbon material with excellent performance. The mass of the organic solvent is generally controlled to be 30-100 times the mass of the block copolymer, for example, it can be a specific value of 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 times, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 70-100 times.

[0079] In the above preparation method, in S1, the organic solvent includes one or more of N,N-dimethylformamide (DMF), tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO);

[0080] In some specific embodiments, when the organic solvent comprises a combination of N,N-dimethylformamide (DMF), tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO), the volume ratio of N,N-dimethylformamide (DMF), tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO) can be 1: (1-3):1.

[0081] According to a specific embodiment of the present invention, S1 further includes dispersing the mixed block copolymer, metal complex, organic chelating agent and organic solvent before the self-assembly reaction. The dispersion may be ultrasonic dispersion, and the ultrasonic dispersion time is 30-120 min, for example, specific values ​​such as 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc., and a range with any two of the above specific values ​​as endpoints, and may further be 60-100 min.

[0082] In the above preparation method, in step S1, the self-assembly reaction can be ensured to proceed smoothly by controlling the temperature of the self-assembly reaction. If the reaction temperature is too low, the reaction will not proceed easily; if the reaction temperature is too high, the reaction rate will be too fast, and the reaction process will be difficult to control. In step S1, the temperature of the self-assembly reaction is usually controlled at 60-100℃, for example, specific values ​​such as 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, and any two of the above specific values ​​as endpoints, and further, it can be 70-90℃; the time of the self-assembly reaction is usually controlled at 6-24h, for example, specific values ​​such as 6h, 10h, 12h, 16h, 20h, 24h, and any two of the above specific values ​​as endpoints, and further, it can be 12-20h.

[0083] In the above preparation method, in step S1, stirring can be performed during the self-assembly reaction. By controlling the stirring speed, uniform assembly can be promoted, and unevenness caused by excessively fast or slow stirring speeds can be avoided. In some specific embodiments, the stirring speed is typically 20 r / min to 100 r / min, for example, specific values ​​such as 20 r / min, 30 r / min, 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min, and 100 r / min, as well as a range with any two of the above specific values ​​as endpoints, for example, 50-70 r / min.

[0084] In the above preparation method, in S2, the polymeric monomers can achieve polymerization and crosslinking through in-situ oxidative polymerization. Specifically, the polymeric monomers can undergo polymerization under the action of an initiator and be mixed with the self-assembled precursor obtained in S1 to obtain a polymer / metal composite precursor. In some specific embodiments, the polymer / metal composite precursor can have an ordered structure; furthermore, the polymer / metal composite precursor can retain the ordered structure of the self-assembled precursor.

[0085] In the above preparation method, in step S2, by controlling the amount of polymeric monomer relative to the block copolymer, it is helpful to retain the ordered self-assembled structure of the self-assembled precursor during the polymerization process, thereby generating carbon material with uniformly distributed pore size during subsequent pyrolysis. This results in a multi-level porous carbon material with micropores, mesopores, and macropores, which is beneficial for improving battery performance. The mass of the polymeric monomer is generally controlled to be 0.5-2 times the mass of the block copolymer, for example, specific values ​​such as 0.5 times, 1 times, 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 2 times, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 1-1.5 times.

[0086] In the above preparation method, in S2, the polymeric monomer includes one or more of pyrrole, aniline, thiophene, pyrrole derivatives, aniline derivatives, and thiophene derivatives.

[0087] In the above preparation method, in step S2, the initiator includes one or a combination of two or more of ammonium persulfate, potassium persulfate, and hydrogen peroxide. These initiators also possess oxidizing properties, enabling the monomers to undergo polymerization under oxidative conditions.

[0088] In some specific embodiments, in S2, the initiator may be added in solution form, and the concentration of the initiator solution is 1-5 wt%.

[0089] In the above preparation method, in S2, the mass of the initiator is 0.1-0.3 times the mass of the polymer monomer, for example, specific values ​​such as 0.1 times, 0.15 times, 0.2 times, 0.25 times, 0.3 times, etc., and a range with any two of the above specific values ​​as endpoints.

[0090] In the above preparation method, in S2, the temperature of the in-situ oxidative polymerization reaction is 20-50℃, for example, specific values ​​such as 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 20-40℃; the time of the in-situ oxidative polymerization reaction is 4-12h, for example, specific values ​​such as 4h, 6h, 8h, 10h, 12h, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 8-10h.

[0091] In the above preparation method, in step S2, the protective atmosphere includes an inert gas and / or nitrogen, and the inert gas may include argon.

[0092] In the above preparation method, S3 undergoes a pyrolysis activation reaction, thereby forming a porous carbon material. Furthermore, this invention employs a gradient pyrolysis (i.e., stepwise pyrolysis) method to achieve pyrolysis. This gradient pyrolysis first occurs at a low temperature to slowly remove volatiles, preventing pore collapse and forming a stable carbon framework; then, a pore-expanding reaction and the formation of a graphitized microcrystalline structure occur at a high temperature, resulting in a hierarchical porous structure. The formation of micropores is related to the pyrolysis process, while the formation of mesopores and macropores is related to the formation of precursors from S1 and S2, as well as the pyrolysis process of S3.

[0093] In the above preparation method, in step S3, the gradient pyrolysis includes a first pyrolysis and a second pyrolysis performed sequentially. Specifically, the gradient pyrolysis process includes: heating to 300-500℃ at a heating rate of 2-10℃ / min and holding for 1-3 hours (performing the first pyrolysis), and then heating to 700-1000℃ at a heating rate of 3-8℃ / min and holding for 2-5 hours (performing the second pyrolysis). The heating rate of the first pyrolysis process is generally 2-10℃ / min, for example, specific values ​​such as 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 3-5℃ / min; the temperature of the first pyrolysis process is generally 300-500℃, for example, specific values ​​such as 300℃, 350℃, 400℃, 450℃, 500℃, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 350-450℃; the holding time of the first pyrolysis process is generally 1-3h, for example, specific values ​​such as 1h, 1.5h, 2h, 2.5h, 3h, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 1.5h- 2.5h; the heating rate of the second pyrolysis process is generally 3-8℃ / min, for example, specific values ​​such as 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 4-6℃ / min; the temperature of the second pyrolysis process is generally 700-1000℃, for example, specific values ​​such as 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 800-900℃; the holding time of the second pyrolysis process is generally 2-5h, for example, specific values ​​such as 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 3h-4h.

[0094] In the above preparation method, in step S4, the acid washing process involves an etching reaction to remove metal from the material.

[0095] In the above preparation method, in step S4, the strong acid in the mixed solution of strong acid and hydrogen peroxide includes one of the following: hydrochloric acid (concentrated hydrochloric acid) with a mass concentration of 36-38%, sulfuric acid (concentrated sulfuric acid) with a mass concentration of 98% or higher, and nitric acid (concentrated nitric acid) with a mass concentration of 68% or higher. The mass concentration of the hydrogen peroxide can be 30%. In some specific embodiments, the volume ratio of the strong acid to hydrogen peroxide is 1:(2-5), for example, specific values ​​such as 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, etc., and a range with any two of the above specific values ​​as endpoints, further being 1:3-5.

[0096] In the above preparation method, in step S4, the etching efficiency and etching effect can be adjusted by controlling the amount of acidic oxidant (a mixed solution of strong acid and hydrogen peroxide), the temperature of the acid pickling treatment, and the time. In some specific embodiments, appropriately increasing the amount of the mixed solution can improve the etching efficiency, and appropriately increasing the reaction temperature and time can also obtain a more obvious etching effect.

[0097] In the above preparation method, in S4, the mass of the acidic oxidant (a mixed solution of strong acid and hydrogen peroxide) is 20-50 times the mass of the cubic carbon / metal composite material, for example, specific values ​​such as 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, 50 times, etc., and a range with any two of the above specific values ​​as endpoints, and can further be 30-50 times.

[0098] In the above preparation method, in step S4, the pickling temperature is 60-90℃, for example, specific values ​​such as 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 70-90℃; the pickling time is 5-15h, for example, specific values ​​such as 5h, 7h, 9h, 10h, 11h, 13h, 15h, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 10-13h.

[0099] In the above preparation method, in step S4, the drying temperature is 80-120℃, for example, specific values ​​such as 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 100-120℃; the drying time is 8-24h, for example, specific values ​​such as 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 12-16h.

[0100] According to a specific embodiment of the present invention, the above preparation method may further include S5: surface modification of the dried product of S4 to introduce heteroatoms, and the resulting electrode material includes surface-modified three-dimensional cubic porous carbon.

[0101] In the above preparation method, in S5, the dried product of S4 can be further surface modified by plasma method to introduce heteroatoms or functional groups to increase the active sites of the electrode material and enhance its conductivity.

[0102] In the above preparation method, in step S5, the surface modification process is as follows: the dried product of step S4 is subjected to plasma treatment in a low-temperature plasma.

[0103] In the above preparation method, in S5, the power of the plasma treatment is 50-200W, for example, specific values ​​such as 50W, 100W, 150W, 180W, 200W, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 100-180W; the time is 5-30min, for example, specific values ​​such as 5min, 10min, 15min, 20min, 25min, 30min, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 15-25min.

[0104] In the above preparation method, in step S5, the plasma treatment, through the dissociation of different gases on the porous carbon surface, enables controllable doping of oxygen-, nitrogen-, sulfur-, and nitrogen-containing functional groups. Furthermore, the plasma treatment has an etching effect on the porous carbon, increasing the number of active sites and enhancing conductivity. High-energy particle bombardment induces disorder in the carbon layer, increasing the proportion of edge defects and sp³ hybridized carbon.

[0105] In the above preparation method, in S5, the temperature of the low-temperature plasma is 50-200℃, for example, specific values ​​such as 50℃, 75℃, 100℃, 125℃, 150℃, 175℃, 200℃, etc., and a range with any two of the above specific values ​​as endpoints.

[0106] In the above preparation method, in step S5, the low-temperature plasma includes one or more combinations of plasmas containing the following gases: oxygen-containing gas, nitrogen-containing gas, sulfur-containing gas, and phosphorus-containing gas. In some specific embodiments, the oxygen-containing gas may include oxygen, the nitrogen-containing gas may include nitrogen and / or ammonia, the sulfur-containing gas may include sulfur dioxide, and the phosphorus-containing gas may include one or more combinations of PH3, PCl3, and PF5.

[0107] Specifically, the low-temperature plasma includes one or more combinations of the following gases: oxygen, nitrogen, ammonia, sulfur dioxide, PH3, PCl3, and PF5.

[0108] According to a specific embodiment of the present invention, the above preparation method may specifically include:

[0109] S1. A block copolymer, a metal complex, and an organic chelating agent in a mass ratio of 1:(0.5-2):(0.5-3) are mixed in an organic solvent and ultrasonically dispersed to form a first system. The mass of the organic solvent is 30-100 times the mass of the block copolymer. The first system is subjected to a self-assembly reaction at 60-100℃ for 6-24 hours to form an ordered self-assembled precursor.

[0110] S2. The ordered self-assembled precursor is mixed with polymeric monomers and initiators to form a second system. The mass of the polymeric monomers is 0.5-2 times the mass of the block copolymer, and the mass of the initiator is 0.1-0.3 times the mass of the polymeric monomers. The mixture is subjected to in-situ oxidative polymerization at 20-50°C for 4-12 hours to obtain an ordered polymer / metal composite precursor.

[0111] S3. Under a protective atmosphere, the ordered polymer / metal composite precursor is subjected to gradient pyrolysis: the temperature is increased to 300-500℃ at a heating rate of 2-10℃ / min and held for 1-3h, and then the temperature is increased to 700-1000℃ at a heating rate of 3-8℃ / min and held for 2-5h to obtain cubic carbon / metal composite material.

[0112] S4. The carbon / metal composite material is added to an acidic oxidant and acid-washed at 60-90℃ for 5-15 hours. After acid washing, it is filtered, washed, and dried. The dried product is the electrode material, which includes a three-dimensional cubic porous carbon material. The acidic oxidant includes a mixed solution of strong acid and hydrogen peroxide in a volume ratio of 1:(2-5), and the mass of the acidic oxidant is 20-50 times the mass of the cubic carbon / metal composite material. The acidic oxidant includes a mixed solution of strong acid and hydrogen peroxide.

[0113] Optionally, the above preparation method further includes S5, subjecting the dried product of S4 to plasma treatment in a low-temperature plasma at a power of 50-200W for 5-30 minutes to obtain an electrode material, which includes surface-modified three-dimensional cubic porous carbon.

[0114] The preparation method provided by this invention is simple, efficient, and highly controllable, enabling the preparation of carbon materials with regular cubic morphology and well-developed hierarchical pore structure as electrode materials. This is of great significance for expanding the application fields of porous carbon materials and improving their performance. Such cubic porous carbon materials are expected to provide a large specific surface area while achieving more efficient mass transport through their regular morphology and hierarchical pore structure, exhibiting excellent performance in energy storage and conversion, catalysis, adsorption and separation, and other fields.

[0115] The present invention also provides an electrode material obtained by the preparation method described above.

[0116] According to a specific embodiment of the present invention, the electrode material comprises three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon. When the above preparation method includes S1 to S4, the electrode material obtained therefrom comprises three-dimensional cubic porous carbon; when the above preparation method includes S1 to S5, the electrode material obtained therefrom comprises surface-modified three-dimensional cubic porous carbon.

[0117] According to a specific embodiment of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a cubic morphology with a side length of 1-30 μm, for example, specific values ​​such as 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc., and a range with any two of the above specific values ​​as endpoints, and further, it can be 5-10 μm.

[0118] According to specific embodiments of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a hierarchical pore structure; specifically, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has micropores, mesopores, and macropores; in some specific embodiments, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a well-developed hierarchical pore structure, that is, it has well-developed micropores, mesopores, and macropores; in some more specific embodiments, the micropores, mesopores, and macropores of the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) can be interconnected.

[0119] According to a specific embodiment of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a specific surface area of ​​1200-3500 m². 2 / g, for example, 1200m 2 / g, 1500m 2 / g、2000m 2 / g、2200m 2 / g、2500m 2 / g、27000m 2 / g、3000m 2 / g、32000m 2 / g、3500m 2 The specific values ​​such as / g and the range with any two of the above specific values ​​as endpoints can be further defined as 2000-3500m. 2 / g.

[0120] According to a specific embodiment of the present invention, the porosity of the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) is 65-95%, for example, specific values ​​such as 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc., and a range with any two of the above specific values ​​as endpoints, and may further be 75-90%.

[0121] According to a specific embodiment of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a pore volume of 1-2 cm³. 3 / g, for example, 1cm 3 / g, 1.1cm 3 / g, 1.2cm 3 / g, 1.3cm 3 / g, 1.4cm 3 / g, 1.5cm 3 / g, 1.6cm 3 / g, 1.7cm 3 / g, 1.8cm 3 / g, 1.9cm 3 / g、2cm 3 The specific values ​​such as / g and the range with any two of the above specific values ​​as endpoints.

[0122] According to a specific embodiment of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) has a pore size of 1-90 nm. Specifically, the micropores have a pore size less than 2 nm; the mesopores have a pore size of 2-50 nm; and the macropores have a pore size greater than 50 nm, for example, 50-90 nm, specifically values ​​such as 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, and 90 nm, as well as a range with any two of the above specific values ​​as endpoints.

[0123] According to a specific embodiment of the present invention, the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) comprises carbon and heteroatoms. The carbon content is 95% or more by mass, and can be 95-100%, specifically 95%, 96%, 97%, 98%, 99%, 100%, or any two of the above values ​​as endpoints; the heteroatom content is 5% or less by mass, and can be 0-5%, specifically 0%, 1%, 2%, 3%, 4%, 5%, or any two of the above values ​​as endpoints. In some specific embodiments, the heteroatoms include one or more combinations of nitrogen, sulfur, phosphorus, and oxygen.

[0124] According to a specific embodiment of the present invention, in the electrode material (three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon), the pore volume of the micropores accounts for 50-80% of the total pore volume, for example, specific values ​​such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, and any two of the above specific values ​​as endpoints; the pore volume of the mesopores accounts for 10-40% of the total pore volume, for example, specific values ​​such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, and any two of the above specific values ​​as endpoints; the pore volume of the macropores accounts for 5-30% of the total pore volume, for example, specific values ​​such as 5%, 10%, 15%, 20%, 25%, 30%, and any two of the above specific values ​​as endpoints.

[0125] According to a specific embodiment of the present invention, the surface-modified three-dimensional cubic porous carbon comprises carbon and heteroatoms. The carbon content is 95% or more by mass, specifically 95-100%, including values ​​such as 95%, 96%, 97%, 98%, 99%, 100%, and any two of these values ​​as endpoints. The heteroatom content is 5% or less by mass, specifically 0.001%, 0.01%, 0.1%, 1%, 2%, 3%, 4%, 5%, and any two of these values ​​as endpoints. In some embodiments, the heteroatoms include one or more combinations of nitrogen, sulfur, phosphorus, and oxygen.

[0126] According to a specific embodiment of the present invention, in the surface-modified three-dimensional cubic porous carbon, the micropore volume accounts for 50-80% of the total pore volume, for example, specific values ​​such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, and any two of the above specific values ​​as endpoints; the mesopore volume accounts for 10-40% of the total pore volume, for example, specific values ​​such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, and any two of the above specific values ​​as endpoints; the macropore volume accounts for 5-30% of the total pore volume, for example, specific values ​​such as 5%, 10%, 15%, 20%, 25%, 30%, and any two of the above specific values ​​as endpoints.

[0127] The present invention also provides a supercapacitor, wherein the electrode material of the supercapacitor includes the electrode material provided by the present invention (including unmodified three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon).

[0128] According to a specific embodiment of the present invention, the electrolyte of the supercapacitor includes one of sulfuric acid solution, potassium hydroxide solution, and organic electrolyte.

[0129] According to a specific embodiment of the present invention, the electrode material provided by the present invention has high mechanical stability and structural stability, and is not prone to structural collapse during cycling. Therefore, the supercapacitor made from it has good cycling stability.

[0130] According to a specific embodiment of the present invention, a supercapacitor using the electrode material of the present invention (including unmodified three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) as the electrode material has a specific capacitance of 280 F / g or more, and more preferably 290 F / g or more at a current density of 1 A / g; the supercapacitor has a specific capacitance of 270 F / g or more at a current density of 50 A / g; and the supercapacitor retains a capacitance of ≥99% after 10,000 cycles at a current density of 6 A / g, and more preferably ≥99.7%, and even more preferably ≥99.8% or ≥99.9%.

[0131] The present invention also provides the application of the above-mentioned electrode materials (including unmodified three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon) in the preparation of catalyst supports, electrocatalysts, biosensors, gas adsorption and separation materials, and water treatment adsorption materials.

[0132] Example 1

[0133] This embodiment provides an electrode material, and the preparation method of the electrode material includes the following steps:

[0134] (1) Self-assembly molding steps: Weigh 0.5g of polystyrene-polyvinylpyrrolidone (PS-PVP, Mn=32000-b-8000), 0.5g of iron acetylacetone (Fe(C5H7O2)3, average particle size about 100nm) and 0.25g of trisodium citrate, add them to 50mL of N,N-dimethylformamide (DMF), ultrasonically disperse for 60min, and then stir at 80℃ at a speed of 50r / min for 12h to form a reddish-brown transparent solution as a self-assembly precursor;

[0135] (2) In-situ polymerization step: 0.5 g of pyrrole monomer and 10 mL of aqueous solution containing 0.1 g of ammonium persulfate (1 wt%) were slowly added dropwise to the above self-assembled precursor solution. The mixture was reacted at 30 °C for 8 h to obtain a black suspension. The obtained suspension was centrifuged, washed 3 times, and dried to obtain the polymer / metal composite precursor.

[0136] (3) Gradient pyrolysis step: The polymer / metal composite precursor is placed in a tube furnace and heated to 400℃ at a heating rate of 5℃ / min under a nitrogen atmosphere and held for 2h. Then, it is heated to 800℃ at a heating rate of 5℃ / min and held for 3h. It is then naturally cooled to room temperature to obtain cubic carbon / iron composite material.

[0137] (4) Selective etching step: The above carbon / iron composite material is added to a mixed solution of concentrated hydrochloric acid (concentration 36wt%) and hydrogen peroxide (mass concentration 30wt.%) (volume ratio 1:3, mass of the mixed solution is 30 times the mass of the carbon / iron composite material), stirred at 80℃ for 10h for acid treatment, filtered, washed with water until neutral, and dried at 100℃ for 12h to obtain cubic porous carbon material;

[0138] (5) Surface modification step: The obtained cubic porous carbon material is placed in a low-temperature oxygen plasma treatment instrument. The temperature of the low-temperature plasma is 60℃, the power is 100W, and the treatment time is 15min to obtain the electrode material. The electrode material is a surface-modified cubic porous carbon material (named sample S1).

[0139] Figure 1 is a scanning electron microscope (SEM) image of the cubic carbon / metal composite material (product of step (3)) prepared in Example 1. Figure 2 is a SEM image of the electrode material (i.e., sample S1) prepared in Example 1. Figure 3 is a high-magnification SEM image of the electrode material prepared in Example 1. Figure 4 is a transmission electron microscope (TEM) image of the electrode material prepared in Example 1. Figure 5 is a pore distribution curve of the electrode material prepared in Example 1.

[0140] As shown in Figure 1, the cubic carbon / iron composite material obtained in the gradient pyrolysis step, observed by scanning electron microscopy (SEM), retains its complete cubic shape. After selective etching and surface modification, the morphology of sample S1, observed by SEM (as shown in Figure 2), still exhibits a clear cubic shape with a side length of approximately 5 μm, and all edges and corners of the cubes remain intact. Figure 3 shows the presence of macropores larger than 50 nm. Transmission electron microscopy (TEM) observation (as shown in Figure 4) reveals that the cubic structure of the electrode material contains a well-developed hierarchical porous structure, including micropores of 1-2 nm and mesopores of 2-20 nm. Nitrogen adsorption-desorption testing confirmed the specific surface area of ​​sample S1 to be 2420 m². 2 / g, pore volume is 1.65cm³ 3 The pore size distribution of micropores and mesopores (as shown in Figure 5) is mainly concentrated in the range of 1-20 nm, while the macropore size is 55-80 nm, and the overall porosity of the material is 78%. In sample S1, the mass content of carbon is 98.6%, and the mass content of heteroatoms is 1.4%; the micropore volume accounts for 71.2% of the total pore volume, the mesopore volume accounts for 22.5% of the total pore volume, and the macropore volume accounts for 6.3% of the total pore volume.

[0141] This embodiment also provides a supercapacitor, specifically a two-electrode symmetrical supercapacitor. The raw material includes the electrode material of this embodiment (surface-modified cubic porous carbon material). The preparation method of the two-electrode symmetrical supercapacitor includes:

[0142] 80 wt% of electrode material, 10 wt% carbon black, and 10 wt% water-based binder (LA133 binder, also known as an aqueous dispersion of acrylonitrile copolymer) were dispersed in water and stirred for 5 hours to prepare a water-based slurry. The resulting water-based slurry was then uniformly coated onto circular nickel foam to prepare the working electrode, which was then dried in a vacuum oven. Glass fiber and 6M KOH solution were used as the separator and electrolyte, respectively, with working electrodes of equal mass on both sides of the separator and electrolyte, assembling a symmetrical supercapacitor.

[0143] After the supercapacitor was assembled, its electrochemical performance was evaluated. Figure 6 shows the cyclic voltammetry curve of the supercapacitor prepared in Example 1. Figure 7 shows the rate performance curve of the supercapacitor prepared in Example 1. Figure 8 shows the cycle performance curve of the supercapacitor prepared in Example 1.

[0144] Figure 6 shows the cyclic voltammetry (CV) curves, which exhibit a good rectangular shape at a scan rate of 30 mV / s, indicating ideal double-layer capacitance behavior. Constant current charge-discharge tests show the specific capacitance values ​​at different current densities, as shown in Figure 7. At a current density of 1 A / g, the specific capacitance reaches 285 F / g; then, at a high current density of 50 A / g, it still maintains a specific capacitance of 270 F / g, with a capacity retention rate as high as 94.7% (capacitance retention rate = specific capacitance at 50 A / g current density / specific capacitance at 1 A / g current density), demonstrating excellent rate performance. Cyclic stability tests conducted at a current density of 6 A / g (as shown in Figure 8) show that after 10,000 cycles, the capacity retention rate is as high as 99.8%, proving that this material has excellent electrochemical stability as a supercapacitor electrode.

[0145] Example 2

[0146] This embodiment provides an electrode material, and the preparation method of the electrode material includes the following steps:

[0147] (1) Self-assembly molding steps: Weigh 0.8g of polystyrene-polyethylene glycol (PS-PEG, Mn=25000-b-10000), 1.2g of cobalt acetylacetonate (Co(C5H7O2)2, average particle size of 120nm) and 0.6g of disodium ethylenediaminetetraacetate (EDTA-2Na), add them to 60mL of a mixed solvent of tetrahydrofuran (THF) and DMF (volume ratio 1:1), ultrasonically disperse for 90min, and then stir at 70℃ at a speed of 60r / min for 18h to form a purple transparent solution as a self-assembly precursor;

[0148] (2) In-situ polymerization step: 0.8 g of aniline monomer and 15 mL of aqueous solution containing 0.15 g of potassium persulfate (1 wt%) were slowly added dropwise to the above self-assembled precursor solution. The mixture was reacted at 25 °C for 10 h to obtain a dark green suspension. The obtained suspension was centrifuged, washed 3 times, and dried to obtain the polymer / metal composite precursor.

[0149] (3) Gradient pyrolysis step: The polymer / metal composite precursor is placed in a tube furnace and heated to 350℃ for 2h at a heating rate of 3℃ / min under an argon atmosphere. Then, it is heated to 900℃ at a heating rate of 4℃ / min and held for 4h. It is then naturally cooled to room temperature to obtain cubic carbon / cobalt composite material.

[0150] (4) Selective etching step: The above carbon / cobalt composite material is added to a mixed solution of concentrated sulfuric acid (98% by mass) and hydrogen peroxide (30 wt.% by mass) (volume ratio of 1:4, the mass of the mixed solution is 30 times the mass of the carbon / cobalt composite material), stirred at 70°C for 12 h for acid treatment, filtered, washed with water until neutral, and dried at 120°C for 12 h to obtain cubic porous carbon material;

[0151] (5) Surface modification step: The obtained cubic porous carbon material is placed in a low-temperature oxygen plasma treatment instrument with a power of 150W and a treatment time of 20min. The temperature of the low-temperature plasma is the same as in Example 1. Electrode material is obtained, which is a surface-modified cubic porous carbon material (named sample S2).

[0152] Morphological characterization of sample S2 revealed a uniform cubic shape with a side length of approximately 8 μm, a slightly rough surface, and a rich hierarchical network of pores within. The specific surface area of ​​sample S2 was 2520 m². 2 / g, pore volume is 1.70cm³ 3 The material has a porosity of 82%, with micropores and mesopores mainly distributed in the range of 1-18 nm, macropores ranging from 55-90 nm, and a carbon content of 99.5% by mass and heteroatom content of 0.5%. Micropores account for 73.8% of the total pore volume, mesopores for 21.5%, and macropores for 4.7%.

[0153] This embodiment also provides a supercapacitor, specifically a two-electrode symmetrical supercapacitor. The raw materials include the electrode materials of this embodiment. The preparation method of the two-electrode symmetrical supercapacitor is similar to that of Embodiment 1, except that the electrode materials of Embodiment 1 are replaced with the electrode materials of this embodiment. Other raw materials and operation steps are the same as in Embodiment 1.

[0154] After assembly, the supercapacitor underwent electrochemical testing according to the method described in Example 1. Constant current charge-discharge testing showed that at a current density of 1 A / g, the supercapacitor achieved a specific capacitance of 290 F / g; at a high current density of 50 A / g, the supercapacitor still maintained a specific capacitance of 275 F / g, with a capacity retention of 94.8%, demonstrating excellent rate performance. Cyclic stability testing at a current density of 6 A / g showed that after 10,000 cycles, the capacity retention was as high as 99.7%, proving that this material has excellent electrochemical stability as a supercapacitor electrode.

[0155] Example 3

[0156] This embodiment provides an electrode material, and the preparation method of the electrode material includes the following steps:

[0157] (1) Self-assembly molding steps: Weigh 0.6g of polystyrene-polyacrylic acid (PS-PAA, Mn=28000-b-7000), 0.9g of nickel acetylacetone (Ni(C5H7O2)2, average particle size about 200nm) and 0.4g of sodium potassium tartrate (purity 99.0%), add them to 45mL of dimethyl sulfoxide (DMSO, mass is 75 times the mass of the block copolymer), ultrasonically disperse for 75min, and then stir at 85℃ at a speed of 60r / min for 15h to form a green transparent solution as a self-assembly precursor;

[0158] (2) In-situ polymerization step: 0.9 g of thiophene monomer (the mass of the monomer is 1.5 times the mass of the block copolymer) and an aqueous solution (18 mL, concentration 1 wt%) containing 0.18 g of hydrogen peroxide (the mass of the initiator is 0.2 times the mass of the monomer) were slowly added dropwise to the above self-assembled precursor solution. The reaction was carried out at 35 °C for 10 h to obtain a brown-black suspension. The obtained suspension was centrifuged, washed 3 times, and dried to obtain the polymer / metal composite precursor.

[0159] (3) Gradient pyrolysis step: The polymer / metal composite precursor is placed in a tube furnace and heated to 380℃ at a heating rate of 4℃ / min under a nitrogen atmosphere and held for 1.5h. Then, it is heated to 850℃ at a heating rate of 6℃ / min and held for 3.5h. It is then naturally cooled to room temperature to obtain cubic carbon / nickel composite material.

[0160] (4) Selective etching step: The above carbon / nickel composite material is added to a mixed solution of concentrated hydrochloric acid (mass concentration of 36-38%) and hydrogen peroxide (mass concentration of 30wt.%) (volume ratio of 1:3.5, the mass of the mixed solution is 35 times the mass of the carbon / nickel composite material), stirred at 75℃ for 11h for acid treatment, filtered, washed with water until neutral, and dried at 110℃ for 14h to obtain cubic porous carbon material;

[0161] (5) Surface modification step: The obtained cubic porous carbon material was placed in a low-temperature oxygen plasma treatment instrument with a power of 120W and a treatment time of 18min. The temperature of the low-temperature plasma was the same as in Example 1. Electrode material was obtained, which was a surface-modified cubic porous carbon material (named sample S3).

[0162] SEM observation of sample S3 revealed a regular cubic shape with sides approximately 6 μm in length, and clearly defined edges and corners. TEM observation showed a well-developed hierarchical porous structure within the cube, including micropores of 1-2 nm and mesopores of 5-18 nm. Nitrogen adsorption-desorption testing determined the specific surface area of ​​sample S3 to be 2682 m². 2 / g, pore volume is 1.75cm³ 3The material has a porosity of 80%, with micropores and mesopores mainly distributed in the 1-20 nm range, macropores ranging from 55-85 nm, and a carbon content of 97.6% by mass and heteroatom content of 2.4% by mass. Micropores account for 76.8% of the total pore volume, mesopores for 19.6%, and macropores for 3.6%.

[0163] This embodiment also provides a supercapacitor, specifically a two-electrode symmetrical supercapacitor. The raw materials include the electrode materials of this embodiment. The preparation method of the two-electrode symmetrical supercapacitor is similar to that of Embodiment 1, except that the electrode materials of Embodiment 1 are replaced with the electrode materials of this embodiment. Other raw materials and operation steps are the same as in Embodiment 1.

[0164] After assembly, the supercapacitor underwent electrochemical testing according to the method described in Example 1. Constant current charge-discharge testing showed that at a current density of 1 A / g, the supercapacitor achieved a specific capacitance of 292 F / g; at a high current density of 50 A / g, the supercapacitor still maintained a specific capacitance of 276 F / g, with a capacity retention of 94.5%, demonstrating excellent rate performance. Cyclic stability testing at a current density of 6 A / g showed that after 10,000 cycles, the capacity retention was as high as 99.9%, proving that this material has excellent electrochemical stability as a supercapacitor electrode.

[0165] Example 4

[0166] This embodiment provides an electrode material, and the preparation method of the electrode material includes the following steps:

[0167] (1) Self-assembly molding steps: Weigh 1.0g of polystyrene-polyvinylpyrrolidone-polyethylene glycol (PS-PVP-PEG, Mn=20000-b-5000-b-8000), 1.5g of copper acetylacetone (Cu(C5H7O2)2, average particle size about 250nm) and 0.7g of ethylenediaminetetraacetic acid (EDTA), add them to 80mL of a mixed solvent of DMF and THF (volume ratio 2:1, the mass of the mixed solvent is 80 times the mass of the block copolymer), ultrasonically disperse for 100min, and then stir at 75℃ at a speed of 65r / min for 20h to form a blue transparent solution as a self-assembly precursor;

[0168] (2) In-situ polymerization step: 1.2 g of pyrrole monomer (the mass of the monomer is 1.2 times the mass of the block copolymer) and an aqueous solution (24 mL, concentration of 1.25 wt%) containing 0.3 g of ammonium persulfate (the mass of the initiator is 0.25 times the mass of the monomer) were slowly added dropwise to the above self-assembled precursor solution. The reaction was carried out at 40 °C for 9 h to obtain a black suspension. The obtained suspension was centrifuged, washed 3 times, and dried to obtain the polymer / metal composite precursor.

[0169] (3) Gradient pyrolysis step: The polymer / metal composite precursor is placed in a tube furnace and heated to 420℃ at a heating rate of 3.5℃ / min under an argon atmosphere and held for 2.5h. Then, it is heated to 880℃ at a heating rate of 4.5℃ / min and held for 4h. It is then naturally cooled to room temperature to obtain cubic carbon / copper composite material.

[0170] (4) Selective etching step: The above carbon / copper composite material is added to a mixed solution of concentrated sulfuric acid (98% by mass) and hydrogen peroxide (30 wt.% by mass) (volume ratio of 1:4.5, the mass of the mixed solution is 45 times the mass of the carbon / copper composite material), stirred at 85°C for 13 h for acid treatment, filtered, washed with water until neutral, and dried at 115°C for 16 h to obtain cubic porous carbon material;

[0171] (5) Surface modification step: The obtained cubic porous carbon material is placed in a low-temperature oxygen plasma treatment instrument with a power of 180W for 25 minutes. The temperature of the low-temperature plasma is the same as in Example 1. Electrode material is obtained, which is a surface-modified cubic porous carbon material (named sample S4).

[0172] Morphological characterization of sample S4 revealed a uniform cubic shape with sides approximately 10 micrometers in length, clearly defined edges and corners, and a slight rough texture on the surface. Transmission electron microscopy showed a highly interconnected hierarchical porous structure within the cube. Nitrogen adsorption-desorption testing determined the specific surface area of ​​sample S4 to be 2755 m² / g. 2 / g, pore volume is 1.80cm³ 3 The material has a porosity of 87%, with micropores and mesopores mainly distributed in the 1-25 nm range, macropores ranging from 55-90 nm, and a carbon content of 99.2% by mass and heteroatom content of 0.8% by mass. Micropores account for 75.6% of the total pore volume, mesopores for 20.2%, and macropores for 4.2%.

[0173] This embodiment also provides a supercapacitor, specifically a two-electrode symmetrical supercapacitor. The raw materials include the electrode materials of this embodiment. The preparation method of the two-electrode symmetrical supercapacitor is similar to that of Embodiment 1, except that the electrode materials of Embodiment 1 are replaced with the electrode materials of this embodiment. Other raw materials and operation steps are the same as in Embodiment 1.

[0174] After assembly, the supercapacitor underwent electrochemical testing according to the method described in Example 1. Constant current charge-discharge testing showed that at a current density of 1 A / g, the supercapacitor achieved a specific capacitance of 295 F / g; at a high current density of 50 A / g, the supercapacitor still maintained a specific capacitance of 278 F / g, with a capacity retention of 94.2%, demonstrating excellent rate performance. Cyclic stability testing at a current density of 6 A / g showed that after 10,000 cycles, the capacity retention was as high as 99.9%, proving that this material has excellent electrochemical stability as a supercapacitor electrode.

[0175] In the above embodiments, the supercapacitor made of the electrode material of the present invention has excellent cycle stability, which shows that the electrode material prepared in the embodiments has high mechanical stability and structural stability, and therefore can maintain the integrity of the material structure without collapse during electrochemical cycling.

[0176] Comparative Example 1

[0177] This comparative example provides a method for preparing porous carbon materials:

[0178] Referring to the preparation method of the electrode material in Example 1, the mass of the organic solvent DMF was adjusted to 300 times the mass of the block copolymer (i.e., 150 mL), and the remaining steps and conditions were the same as in Example 1.

[0179] The specific surface area of ​​the porous carbon material prepared in Comparative Example 1 was only 150 m². 2 The pore size distribution is uneven and mainly concentrated in the 20-40 nm region. Using it as an electrode material for a supercapacitor, it was assembled into a supercapacitor according to the method in Example 1 and electrochemical tests were performed. The specific capacitance of the supercapacitor was measured to be only 45 F / g at a current density of 1 A / g, decreasing to 12 F / g at a current density of 50 A / g, with a capacity retention of only 26.7%. After 10,000 cycles at a current density of 6 A / g, the capacity retention was only 12.6%.

[0180] In Comparative Example 1, excessive solvent usage led to a significant decrease in the performance of the porous carbon. This was mainly because: excessive solvent resulted in excessively low concentrations of the block copolymer and the metal complex, weakening their interaction forces and disrupting the conditions for the formation of an ordered structure during self-assembly. In an overly diluted environment, the block copolymer molecules were too far apart to form a tightly packed, ordered micelle structure, and the metal complex also struggled to interact uniformly with the hydrophilic segments of the block copolymer. This resulted in an irregular structure of the self-assembly precursor, which in turn affected the carbon framework formed after subsequent pyrolysis, leading to an uneven pore structure distribution, predominantly consisting of large mesopores. This uneven pore structure hinders rapid ion transport during charge and discharge, especially at high current densities, resulting in poor rate performance and cycle stability.

[0181] It can be seen that by controlling the amount of organic solvent relative to the block copolymer, the present invention helps the block copolymer, metal complex and organic chelating agent to interact and form an ordered structure during the self-assembly process, thereby obtaining a regular and tightly ordered micelle structure, ensuring that the carbon material has a uniform pore structure and forms a hierarchical pore structure, thus producing a porous carbon material that enables rapid ion transport during charging and discharging and has excellent electrochemical performance (rate performance and cycle stability).

[0182] Comparative Example 2

[0183] This comparative example provides a method for preparing porous carbon materials:

[0184] Referring to the preparation method of the electrode material in Example 2, the amount of the polymeric monomer aniline was adjusted to 3 times the mass of the block copolymer (i.e., 2.4 g), and the remaining steps and conditions were kept the same as in Example 2.

[0185] The porous carbon material prepared in Comparative Example 2 has a specific surface area of ​​only 120 m². 2 The pore size distribution exhibits a bimodal distribution, concentrated in the 2-5 nm and 40-60 nm regions, respectively, lacking a uniform medium-sized mesoporous structure. When used as an electrode material for a supercapacitor, it was assembled into a supercapacitor according to the method in Example 1 and electrochemical tests were performed. The specific capacitance of the supercapacitor was measured to be only 38 F / g at a current density of 1 A / g, decreasing to 10 F / g at a current density of 50 A / g, with a capacity retention of only 26.3%. After 10,000 cycles at a current density of 6 A / g, the capacity retention was only 11.8%.

[0186] In Comparative Example 2, the excessive amount of polymerizable monomers led to a significant decrease in the performance of the porous carbon. This was mainly attributed to the following: Excess aniline monomers were difficult to fully polymerize during in-situ polymerization, and the remaining monomers interfered with the ordered structure of the self-assembled system. Furthermore, excessive polymerizable monomers resulted in an uncontrollable polymerization process, leading to a wide molecular weight distribution and disordered molecular chain arrangement in the formed polyaniline. This uncontrollable polymerization process disrupted the already formed ordered self-assembled structure, causing entanglement and aggregation of polymer chains in the precursor, forming a non-uniform network structure. During subsequent pyrolysis, this non-uniform structure transformed into a carbon material with a non-uniform pore size distribution, forming a bimodal distribution with both micropores and macropores and fewer mesopores. This non-uniform pore structure severely affected the transport efficiency of electrolyte ions within the electrode. While micropores provided a large specific surface area, ion diffusion was limited; while macropores provided rapid ion transport channels, their specific surface area utilization was low. The lack of mesopores connecting micropores and macropores as efficient transport channels meant that active sites in deep micropores were difficult to utilize effectively at high current densities, resulting in poor rate performance. Meanwhile, the non-uniform carbon structure formed by excessive polymerization of monomers has poor stability during long-term charge-discharge cycles and is prone to structural collapse, leading to a decline in cycle performance.

[0187] It can be seen that by controlling the amount of polymerizable monomer relative to block copolymer, the present invention helps to retain the ordered structure of the self-assembled precursor during the polymerization process, thereby generating carbon materials with uniformly distributed pore size during subsequent pyrolysis. This results in a multi-level porous carbon material with micropores, mesopores, and macropores, which is beneficial to improving the ion transport capability of the material, enhancing rate performance and cycle stability, and improving battery performance.

[0188] Comparative Example 3

[0189] This comparative example provides a method for preparing porous carbon:

[0190] Referring to the preparation method of electrode material in Example 3, gradient pyrolysis is replaced with one-step pyrolysis. In step (3), the polymer / metal composite precursor is placed in a tube furnace and heated to 850°C at a heating rate of 6°C / min under a nitrogen atmosphere and held for 3.5 hours. It is then naturally cooled to room temperature to obtain composite carbon material. Subsequent steps are then performed. The remaining conditions and operations are consistent with those in Example 3.

[0191] The porous carbon material prepared in Comparative Example 3 has a specific surface area of ​​only 135 m². 2 / g, as the electrode material of the supercapacitor, was assembled into a supercapacitor according to the method of Example 1 and electrochemical tests were performed. The specific capacitance at a current density of 1A / g was only 40F / g, and the specific capacitance dropped to 9F / g at a current density of 50A / g, with a capacity retention rate of only 22.5%. After 10,000 cycles at a current density of 6A / g, the capacity retention rate was only 10.6%.

[0192] In Comparative Example 3, replacing gradient pyrolysis with a one-step pyrolysis method leads to a significant decrease in the performance of porous carbon. This is mainly attributed to: the rapid increase in temperature during one-step pyrolysis causes local overheating of the precursor, carbon layer fracture, pore collapse, and instability of the carbon skeleton structure; the violent decomposition of the precursor generates a large number of free radicals, initiating random cross-linking, resulting in disordered pores, high closed-pore ratio, and large specific surface area loss. Furthermore, the material exhibits poor electrical conductivity and mechanical strength. One-step pyrolysis lacks phased control over thermodynamics (decomposition path) and kinetics (volatile matter release rate), while gradient pyrolysis, through a temperature-time-atmosphere coordinated process, can achieve step-by-step optimization from molecular pyrolysis to carbon skeleton reconstruction.

[0193] It can be seen that by using gradient pyrolysis, the present invention can ensure that the polymer / metal composite precursor is heated uniformly, thus guaranteeing the pore stability and framework stability of the precursor, thereby obtaining a porous carbon material with a large specific surface area and a well-developed hierarchical pore structure.

[0194] The results above show that the electrode material preparation method of the present invention achieves simultaneous control of the cubic morphology and internal hierarchical pore structure of the electrode material by precisely controlling the self-assembly process, polymerization process and pyrolysis process. The prepared electrode material has excellent electrochemical performance and mechanical stability, and exhibits excellent performance in energy storage and conversion fields.

Claims

1. A method for preparing an electrode material, characterized in that, The preparation method includes: S1, mixing a block copolymer, a metal complex, and an organic chelating agent in an organic solvent at a mass ratio of 1:(0.5-2):(0.5-3) to form a first system, wherein the mass of the organic solvent is 30-100 times the mass of the block copolymer, and subjecting the first system to a self-assembly reaction at 60-100℃ for 6-24 hours to form an ordered self-assembly precursor; S2, mixing the ordered self-assembly precursor with a polymeric monomer and an initiator to form a second system, wherein the mass of the polymeric monomer is 0.5-2 times the mass of the block copolymer, and subjecting the mixture to an in-situ oxidative polymerization reaction to obtain an ordered polymer / metal composite precursor; S3, subjecting the ordered polymer / metal composite precursor to gradient pyrolysis in a protective atmosphere to obtain a cubic carbon / metal composite material; S4, adding the cubic carbon / metal composite material to an acidic oxidant for acid washing treatment, wherein the acidic oxidant includes a mixed solution of strong acid and hydrogen peroxide; filtering, washing, and drying to obtain the electrode material.

2. The preparation method according to claim 1, characterized in that, The block copolymer includes one or more of polystyrene-polyvinylpyrrolidone, polystyrene-polyethylene glycol, polystyrene-polyacrylic acid, and polystyrene-polyvinylpyrrolidone-polyethylene glycol.

3. The preparation method according to claim 1, characterized in that, The number average molecular weight of the block copolymer is 20,000-50,000.

4. The preparation method according to claim 1, characterized in that, The metal complex includes one or more of the following: acetylacetone salts of transition metals, carboxylates of transition metals, and carbamates of transition metals; the transition metal includes one or more of the following: Fe, Co, Ni, Cu, and Zn.

5. The preparation method according to claim 1, characterized in that, The average particle size of the metal complex is 50-500 nm.

6. The preparation method according to claim 1, characterized in that, The organic chelating agent includes one or more of the following: citric acid, tartaric acid, ethylenediaminetetraacetic acid, diethyltriaminepentaacetic acid, trisodium citrate, disodium ethylenediaminetetraacetic acid, and sodium potassium tartrate.

7. The preparation method according to claim 1, characterized in that, The organic solvent includes one or more of N,N-dimethylformamide, tetrahydrofuran, and dimethyl sulfoxide.

8. The preparation method according to claim 1, characterized in that, The polymer monomers include one or more of pyrrole, aniline, thiophene, derivatives of pyrrole, derivatives of aniline, and derivatives of thiophene.

9. The preparation method according to claim 1, characterized in that, The initiator includes one or more of ammonium persulfate, potassium persulfate, and hydrogen peroxide; the mass of the initiator is 0.1-0.3 times the mass of the polymer monomer.

10. The preparation method according to claim 1, characterized in that, The in-situ oxidative polymerization reaction is carried out at a temperature of 20-50℃ for 4-12 hours.

11. The preparation method according to claim 1, characterized in that, The gradient pyrolysis process includes: heating to 300-500℃ at a heating rate of 2-10℃ / min and holding for 1-3 hours, and then heating to 700-1000℃ at a heating rate of 3-8℃ / min and holding for 2-5 hours.

12. The preparation method according to claim 1, characterized in that, The mass of the acidic oxidant is 20-50 times the mass of the cubic carbon / metal composite material.

13. The preparation method according to claim 1, characterized in that, The pickling temperature is 60-90℃, and the pickling time is 5-15h.

14. The preparation method according to claim 1, characterized in that, The preparation method further includes S5: surface modification of the dried product of S4 to introduce heteroatoms, thereby obtaining a surface-modified electrode material; the surface modification process is as follows: plasma treatment of the dried product of S4 in a low-temperature plasma; the power of the plasma treatment is 50-200W, and the time is 5-30min; the low-temperature plasma includes one or more combinations of the following gas plasmas: oxygen-containing gas, nitrogen-containing gas, sulfur-containing gas, and phosphorus-containing gas.

15. An electrode material, characterized in that, The electrode material is obtained by the preparation method described in any one of claims 1-14.

16. The electrode material according to claim 15, characterized in that, The electrode material includes three-dimensional cubic porous carbon and / or surface-modified three-dimensional cubic porous carbon.

17. The electrode material according to claim 16, characterized in that, The electrode material has a cubic morphology with a side length of 1-30 μm.

18. The electrode material according to claim 15, characterized in that, The electrode material has a hierarchical porous structure, including micropores, mesopores, and macropores.

19. The electrode material according to claim 15, characterized in that, The electrode material has a specific surface area of ​​1200-3500 m². 2 / g, the porosity of the electrode material is 65-95%.

20. The electrode material according to claim 18, characterized in that, The electrode material has a pore size of 1-90 nm.

21. The electrode material according to claim 15, characterized in that, The electrode material contains more than 95% carbon by mass and less than 5% heteroatoms by mass. The heteroatoms include one or more combinations of nitrogen, sulfur, phosphorus, and oxygen.

22. The electrode material according to claim 18, characterized in that, In the electrode material, the micropores account for 50-80% of the total pore volume, the mesopores account for 10-40% of the total pore volume, and the macropores account for 5-30% of the total pore volume.

23. A supercapacitor, characterized in that, The electrode material of the supercapacitor includes the electrode material described in any one of claims 15-22.

24. The application of the electrode material according to any one of claims 15-22 in the preparation of catalyst supports, electrocatalysts, biosensors, gas adsorption and separation materials, and water treatment adsorption materials.

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