CS / NiCo-CH composite electrode material, preparation method thereof and supercapacitor

Abstract

The invention discloses a CS / NiCo-CH composite electrode material, a preparation method thereof and a supercapacitor, and belongs to the technical field of supercapacitors. The CS / NiCo-CH composite electrode material comprises a CS substrate and a nickel-cobalt-based hydroxide which is compounded with the CS substrate, the CS matrix is prepared from pyromellitic dianhydride through a carbonization process. According to the preparation method, pyromellitic dianhydride is used as a carbon source, the cost is low, the carbonization efficiency is high, and the CS matrix can be stably prepared through heating, constant-temperature carbonization and subsequent treatment in the inert gas protection atmosphere; the nickel salt and the cobalt salt are selected to be more adaptive to urea, the solubility and reaction activity of the nickel salt and the cobalt salt are more adaptive, the problem that double salt is easily formed in a traditional sulfate system to hinder the reaction can be avoided, in the whole preparation process, the raw material reaction efficiency is high, excessive addition is not needed, energy consumption and pollution can be reduced, the preparation process is easy to amplify on a large scale, and the industrial application cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor technology, specifically relating to a CS / NiCo-CH composite electrode material, its preparation method, and a supercapacitor. Background Technology

[0002] Supercapacitors are widely used in new energy storage, electric vehicles, and other fields due to their fast charge / discharge rates and long cycle life. Their performance is primarily dependent on the electrode materials. Nickel-cobalt based compounds (such as hydroxide carbonate) possess Ni... 2+ / Ni 3+ Co 2+ / Co 3+ Multivalent state reactivity has made it a popular electrode candidate, but existing technologies have significant limitations.

[0003] Traditional nickel-cobalt based materials are mostly pure metal compounds, which are prone to particle agglomeration, resulting in a low specific surface area (usually less than 1000 m²). 2 ·g -1 The active sites are insufficiently exposed, and the lack of a support structure makes them prone to peeling off during cycling, resulting in capacitance retention rates often below 85%. To improve performance, researchers have attempted to combine them with carbon materials. However, traditional processes suffer from high costs and low carbonization efficiency of carbon sources (such as perylene derivatives), and uneven dispersion of carbon materials and metal compounds easily leads to interfacial separation, which in turn reduces electron conduction efficiency. Furthermore, existing composite processes often use metal salt systems such as sulfates, which easily form complex salts with metal ions, hindering the uniform growth of the active phase; the ligands often contain toxic components, making subsequent processing complex and environmentally polluting. Simultaneously, process parameters are difficult to match, easily leading to pore structure collapse or excessive growth of the active phase, resulting in poor batch stability and hindering large-scale application. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing supercapacitor electrode materials, such as low specific capacitance, poor cycle stability, complex preparation process and high cost, the present invention aims to provide a CS / NiCo-CH composite electrode material, its preparation method and a supercapacitor.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a CS / NiCo-CH composite electrode material, comprising a CS matrix and a nickel-cobalt based hydroxide composite with the CS matrix; wherein the CS matrix is ​​prepared by a carbonization process of pyromellitic dianhydride.

[0006] A further improvement of this invention is that the specific surface area of ​​the composite electrode material is ≥1800 m². 2 ·g -1 Specific capacitance ≥ 650 F·g -1After 5000 cycles, the capacitance retention is ≥94%, and the energy density is ≥50Wh·kg. -1 .

[0007] Secondly, the present invention also provides a method for preparing a CS / NiCo-CH composite electrode material, comprising the following steps: Step 1: Place pyromellitic dianhydride in an inert gas protective atmosphere, heat to the carbonization temperature and maintain the temperature, then cool, grind and sieve to obtain the CS matrix; Step 2: Disperse the CS matrix in ultrapure water, and prepare a precipitate-free suspension by stirring and ultrasonic treatment; add nickel salt, cobalt salt and urea to the suspension, and continue stirring and ultrasonic treatment until the solid is completely dissolved to form a homogeneous mixture; Step 3: Transfer the homogeneous mixture to a high-pressure reactor for hydrothermal reaction. After the hydrothermal reaction is completed, allow the reactor to cool naturally to room temperature. Step 4: Filter the solid-liquid mixture in the cooled reactor to obtain a solid product; wash the solid product with ultrapure water until the pH of the filtrate is neutral; vacuum dry the washed solid product, grind it, and sieve it to obtain the CS / NiCo-CH composite electrode material.

[0008] A further improvement of the present invention is that, in step 1, during the preparation of the CS matrix, pyromellitic dianhydride is placed in a high-temperature alumina crucible and calcined before carbonization, and the inert gas is high-purity argon.

[0009] A further improvement of the present invention is that, in step 1, the carbonization temperature is 1050-1150℃, the temperature is maintained for 5.5-6.5 hours, and the sample is passed through a 200-mesh sieve.

[0010] A further improvement of the present invention is that, in step 2, the cobalt salt is cobalt chloride hexahydrate and the nickel salt is nickel chloride hexahydrate.

[0011] A further improvement of the present invention is that, in step 2, during the process of forming a homogeneous mixture, the ultrasonic treatment time is 50-60 minutes.

[0012] A further improvement of the present invention is that, in step 3, the high-pressure reactor is a polytetrafluoroethylene-lined high-pressure reactor; the temperature of the hydrothermal reaction is 100-105℃, and the time is 22-24h.

[0013] A further improvement of the present invention is that, in step 4, the filtration is carried out using a circulating vacuum pump; the vacuum drying is carried out using a vacuum drying oven at a temperature of 65-70℃; after drying, the material is ground using an agate mortar at a grinding rate of 150-200 r / min and then passed through a 200-mesh sieve.

[0014] Thirdly, the present invention also provides a supercapacitor, wherein the electrodes of the supercapacitor comprise the aforementioned CS / NiCo-CH composite electrode material.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a CS / NiCo-CH composite electrode material, which comprises a CS matrix prepared by carbonization of pyromellitic dianhydride and a nickel-cobalt-based hydroxide composite with the CS matrix. The porous structure of the CS matrix guides the uniform deposition of the nickel-cobalt-based hydroxide within the pores, forming a tightly bonded composite structure of "carbon skeleton-metal active phase." This overcomes the limitations of weak interfacial bonding between carbon materials and metal compounds caused by uneven dispersion in traditional composite processes, effectively ensuring electronic conductivity and structural stability, and preventing the detachment of the nickel-cobalt-based hydroxide. Simultaneously, the hierarchical porous structure formed by this composite structure facilitates electrolyte transport and charge storage, synergistically increasing the specific surface area and the number of active sites, resulting in significantly superior capacitance performance compared to traditional composite electrode materials, making it more suitable for the performance requirements of supercapacitors.

[0016] This invention also provides a method for preparing CS / NiCo-CH composite electrode materials. First, pyromellitic dianhydride is used as the carbon source, which is low in cost and has high carbonization efficiency. The CS matrix can be stably prepared by heating and isothermal carbonization under an inert gas protective atmosphere and subsequent treatment. Second, nickel salt, cobalt salt and urea are selected. The solubility and reactivity of nickel salt and cobalt salt are more compatible, which can avoid the problem of complex salt formation that hinders the reaction in traditional sulfate systems. Urea, as a green ligand, has non-toxic decomposition products. Stirring and ultrasonic treatment can fully disperse the CS matrix and form a homogeneous mixture with nickel salt, cobalt salt and urea. Then, by precisely controlling the hydrothermal reaction, particle agglomeration caused by excessive growth can be avoided, ensuring the formation of a hierarchical porous structure. Finally, residues can be removed by rinsing with ultrapure water, without the need for complicated post-treatment. The raw material reaction efficiency is high throughout the preparation process, and excessive addition is not required, which can reduce energy consumption and pollution. The preparation process is easy to scale up, reducing the cost of industrial applications, and can stably prepare CS / NiCo-CH composite electrode materials with excellent performance. Detailed Implementation

[0017] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0018] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0019] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0020] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0021] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0022] This invention provides a CS / NiCo-CH composite electrode material, comprising a CS matrix and a nickel-cobalt based hydroxide composite with the CS matrix; the CS matrix is ​​prepared by a carbonization process of pyromellitic dianhydride.

[0023] The specific surface area of ​​the composite electrode material is ≥1800 m². 2 ·g -1 Specific capacitance ≥ 650 F·g -1 After 5000 cycles, the capacitance retention is ≥94%, and the energy density is ≥50Wh·kg. -1 .

[0024] This invention also provides a method for preparing a CS / NiCo-CH composite electrode material, comprising the following steps: Step 1: Place pyromellitic dianhydride in an inert gas protective atmosphere, heat to the carbonization temperature and maintain the temperature, then cool, grind and sieve to obtain the CS matrix; Step 2: Disperse the CS matrix in ultrapure water, and prepare a precipitate-free suspension by stirring and ultrasonic treatment; add nickel salt, cobalt salt and urea to the suspension, and continue stirring and ultrasonic treatment until the solid is completely dissolved to form a homogeneous mixture; Step 3: Transfer the homogeneous mixture to a high-pressure reactor for hydrothermal reaction. After the hydrothermal reaction is completed, allow the reactor to cool naturally to room temperature. Step 4: Filter the solid-liquid mixture in the cooled reactor to obtain a solid product; wash the solid product with ultrapure water until the pH of the filtrate is neutral; vacuum dry the washed solid product, grind it, and sieve it to obtain the CS / NiCo-CH composite electrode material.

[0025] In some embodiments, during step 1, in the preparation of the CS matrix, pyromellitic dianhydride is placed in a high-temperature alumina crucible and calcined before carbonization, and the inert gas is high-purity argon.

[0026] In some embodiments, in step 1, the carbonization temperature is 1050-1150℃, the temperature is maintained for 5.5-6.5 hours, and the sample is passed through a 200-mesh sieve.

[0027] In some embodiments, in step 2, the cobalt salt is cobalt chloride hexahydrate and the nickel salt is nickel chloride hexahydrate.

[0028] In some embodiments, during step 2, the ultrasonic treatment time is 50-60 minutes in the process of forming a homogeneous mixture.

[0029] In some embodiments, in step 3, the high-pressure reactor is a polytetrafluoroethylene-lined high-pressure reactor; the hydrothermal reaction temperature is 100-105℃, and the time is 22-24h.

[0030] In some embodiments, in step 4, a circulating vacuum pump is used for filtration; a vacuum drying oven is used for vacuum drying at a temperature of 65-70℃; after drying, the material is ground in an agate mortar at a grinding rate of 150-200 r / min and then passed through a 200-mesh sieve.

[0031] The present invention also provides a supercapacitor, wherein the electrodes of the supercapacitor comprise the aforementioned CS / NiCo-CH composite electrode material.

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0034] Example 1 This embodiment provides a method for preparing a CS / NiCo-CH composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g of PMDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PMDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0035] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1 The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0036] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.028g of CS matrix into a 100mL beaker, add 42mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 35min to prepare a black suspension without precipitate; then add 0.0012mol cobalt chloride hexahydrate, 0.0006mol nickel chloride hexahydrate, and 0.0038mol urea, stir at 400r / min for 40min, and sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0037] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0038] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS / NiCo-CH composite electrode material.

[0039] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0040] Example 2 This embodiment provides a method for preparing a CS / NiCo-2 composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g of PMDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PMDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0041] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1 The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0042] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.028g of CS matrix into a 100mL beaker, add 42mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 35min to prepare a black suspension without precipitate; then add 0.0008mol of cobalt chloride hexahydrate, 0.0016mol of nickel chloride hexahydrate, and 0.0038mol of urea, stir at 400r / min for 40min, and sonicate for 60min until the solid is completely dissolved to form a homogeneous mixture.

[0043] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 100℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0044] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS / NiCo-2 composite electrode material.

[0045] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0046] Example 3 This embodiment provides a method for preparing a CS / NiCo-S composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g of PMDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PMDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0047] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1 The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0048] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.028g of CS matrix into a 100mL beaker, add 45mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 35min to prepare a black suspension without precipitate; then add 0.0012mol cobalt sulfate heptahydrate, 0.0006mol nickel sulfate hexahydrate, and 0.0038mol urea, stir at 400r / min for 40min, and sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0049] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0050] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 70 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS / NiCo-S composite electrode material.

[0051] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0052] Example 4 This embodiment provides a method for preparing a CS / NiCo-CH composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g of PMDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PMDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0053] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1 The temperature was increased to 1150℃ and held constant for 5.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 200 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0054] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.025g of CS matrix into a 100mL beaker, add 42mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 35min to prepare a black suspension without precipitate; then add 0.0012mol cobalt chloride hexahydrate, 0.0006mol nickel chloride hexahydrate, and 0.0038mol urea, stir at 400r / min for 40min, and sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0055] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0056] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS / NiCo-CH composite electrode material.

[0057] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0058] Example 5 This embodiment provides a method for preparing a CS / NiCo-CH (urea excess) composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g of PMDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PMDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0059] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0060] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.028g of CS matrix into a 100mL beaker, add 42mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 35min to prepare a black suspension without precipitate; then add 0.0012mol cobalt chloride hexahydrate, 0.0006mol nickel chloride hexahydrate, and 0.005mol urea, stir at 400r / min for 40min, and sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0061] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 24 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0062] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed 5 times with ultrapure water, 50 mL each time, until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS / NiCo-CH composite electrode material.

[0063] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0064] Example 6 This embodiment provides a method for preparing a CS-GO / NiCo-CH composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 2.8g PMDA and 0.3g graphene oxide (GO) using an electronic analytical balance, mix them thoroughly, and place them in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Then, place the crucible in an 80℃ vacuum drying oven for 4 hours. After drying, transfer the crucible to the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. The oxygen content in the tube is confirmed to be below 0.1% by tail gas detection, thus completing the air replacement.

[0065] Step 2, CS-GO matrix carbonization and post-treatment Set the heating program for the tube furnace: 4.5℃·min -1 The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 min. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS-GO matrix, which was then sealed in a desiccator for later use.

[0066] Step 3: CS-GO dispersion mixed with metal salt-urea Weigh 0.028g of CS-GO matrix into a 100mL beaker, add 42mL of ultrapure water, sonicate for 40min, then stir at 350r / min for 30min to prepare a black suspension without precipitate; then add 0.0012mol cobalt chloride hexahydrate, 0.0006mol nickel chloride hexahydrate, and 0.0038mol urea, stir at 400r / min for 40min, sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0067] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0068] Step 4, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS-GO / NiCo-CH composite electrode material.

[0069] The performance of the composite electrode material obtained in this embodiment was tested, and the test results are shown in Table 1.

[0070] Comparative Example 1 This comparative example provides a method for preparing a NiCo-CH (CS-free) composite electrode material, including the following steps: Step 1, Metal salt-urea mixture Weigh 0.0012 mol cobalt chloride hexahydrate, 0.0006 mol nickel chloride hexahydrate, and 0.0038 mol urea into a 100 mL beaker, add 42 mL of ultrapure water, stir at 400 r / min for 40 min, and sonicate for 50 min until the solids are completely dissolved to form a homogeneous mixture.

[0071] Step 2, hydrothermal reaction to prepare the structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0072] Step 3, Post-processing of products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.1 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the NiCo-CH (CS-free) composite electrode material.

[0073] The performance of the composite electrode material obtained in this comparative example was tested, and the test results are shown in Table 1.

[0074] Comparative Example 2 This comparative example provides a method for preparing a CS (PTCDA carbon source) / NiCo-CH composite electrode material, including the following steps: Step 1: Carbon source pretreatment and carbonization preparation Weigh 3g of PTCDA using an electronic analytical balance and place it in a 50mL alumina crucible that has been purified by calcination at 500℃ for 2 hours. Spread the PTCDA evenly on the bottom of the crucible to avoid local accumulation. Then place the crucible in the middle of a high-temperature tubular furnace quartz reaction tube, seal the reaction tube, and purge with high-purity argon gas for 35 minutes. Confirm that the oxygen content in the tube is below 0.1% by tail gas detection, thus completing the air replacement.

[0075] Step 2, CS matrix carbonization and post-treatment Set the heating program for the tube furnace: 3.5℃·min -1The temperature was increased to 1050℃ and held constant for 6.5 hours for carbonization. After carbonization, the product was cooled to room temperature by argon gas for 8 hours. The carbonized product was then removed and ground in an agate mortar at 150 r / min for 20 minutes. The product was then passed through a 200-mesh sieve to obtain a uniform powdered CS matrix, which was then sealed in a desiccator for later use.

[0076] Step 3: CS dispersion mixed with metal salt-urea Weigh 0.028g of CS matrix into a 100mL beaker, add 42mL of ultrapure water, stir at 350r / min for 35min, and sonicate for 45min to prepare a black suspension without precipitate; then add 0.0012mol cobalt chloride hexahydrate, 0.0006mol nickel chloride hexahydrate, and 0.0038mol urea, stir at 400r / min for 40min, and sonicate for 50min until the solid is completely dissolved to form a homogeneous mixture.

[0077] Step 4: Hydrothermal reaction to prepare composite structure Slowly pour the mixture into a 100mL polytetrafluoroethylene-lined high-pressure reactor, ensuring no liquid residue remains. After sealing, place it in a constant-temperature drying oven and maintain the temperature at 105℃ for 22 hours for hydrothermal reaction. After the reaction is complete, close the drying oven and allow the reactor to cool naturally to room temperature for about 3 hours.

[0078] Step 5, Post-processing of composite products and finished products The solid-liquid mixture in the reactor liner was transferred to a Buchner funnel lined with a 0.22 μm filter membrane and filtered by a -0.08 MPa circulating water vacuum pump. The solid product was washed four times with 50 mL of ultrapure water each time until the pH of the filtrate was 7. The washed solid was transferred to a petri dish and dried in a vacuum drying oven at 65 °C and -0.09 MPa for 11 h. After drying, it was ground in an agate mortar for 15 min and passed through a 200-mesh sieve to obtain the CS (PTCDA carbon source) / NiCo-CH composite electrode material.

[0079] The performance of the composite electrode material obtained in this comparative example was tested, and the test results are shown in Table 1.

[0080] Table 1. Electrochemical performance parameters of the composite electrode materials prepared in the embodiments and comparative examples of the present invention.

[0081] As shown in Table 1, the performance differences of the composite electrode materials prepared in the embodiments and comparative examples of this invention mainly stem from the carbon matrix structure, the synergistic effect of metal ions, and the regulatory mechanism of the reaction system. Among them, Example 6 exhibits the best specific surface area and specific capacitance because during the carbonization process of graphene oxide (GO) and PMDA composites, the GO sheets can inhibit the aggregation of the carbon skeleton, forming a richer hierarchical porous structure. Simultaneously, the excellent conductivity of GO reduces charge transfer impedance, significantly improving capacitance and cycle stability, which is a typical manifestation of the synergistic enhancement of "carbon matrix-conductive phase". In Example 4, due to the increased carbonization temperature, the high temperature accelerates the removal of PMDA carboxyl groups and the reorganization of the carbon skeleton, forming more developed channels, thus increasing the specific surface area. At the same time, the shortened isothermal time avoids pore wall collapse caused by over-carbonization; therefore, its capacitance is close to that of Example 1, confirming the matching relationship between "carbonization parameters-pore structure-performance". In Example 5, when urea is in excess, more NH3·H2O is generated, which promotes the uniform deposition of NiCo-CH in the CS channels and increases the active sites. Therefore, the capacitance is slightly higher than that in Example 1. However, excess urea is prone to residue, which leads to a slight decrease in cycle stability. This reflects the trade-off mechanism of "reactant concentration-active sites-stability".

[0082] Example 2 has a higher proportion of nickel ions, while Ni 2+ Hydrolysis activity is lower than Co 2+ High-nickel systems tend to lead to uneven precursor growth, reducing effective active sites and thus decreasing performance. Example 3 uses a sulfate system, which performs worse than the chloride system due to SO42-. 2- It readily forms complex salts with metal ions, hindering the interfacial bonding between NiCo-CH and CS, thereby reducing electron conduction efficiency.

[0083] Comparative Example 1, without the addition of CS, suffers from a lack of porous support framework, leading to particle agglomeration and a sharp drop in specific surface area. Simultaneously, the absence of a carbon matrix to disperse stress makes the material prone to structural spalling during cycling, resulting in significant performance degradation. Comparative Example 2, using PTCDA as the carbon source, performs worse than the PMDA carbon source system. This is because PTCDA has a large molecular weight and low thermal decomposition activity, resulting in insufficient pore structure development after carbonization. Furthermore, its aromatic ring structure easily reduces the conductivity of the carbon matrix, confirming the crucial influence of carbon source characteristics on material performance.

[0084] This invention utilizes PMDA as the carbon source, nickel chloride / cobalt chloride as the metal source, and urea as the ligand to prepare CS / NiCo-CH composite electrode materials via a process of "carbonization to prepare the CS matrix - dispersion mixing - hydrothermal composite - post-treatment". Results show that the specific surface area of ​​the NiCo-CH material without CS support is only 826 m². 2 ·g -1 The CS / NiCo-CH material prepared by this invention has a specific surface area of ​​1865 m². 2 ·g-1 The specific capacitance has been increased to 682 F·g -1 After 5000 cycles, the capacitance retention rate is 94.2%, and the energy density reaches 52.6 Wh·kg. -1 It is significantly superior to traditional nickel-cobalt based materials, providing a new approach for high-performance hybrid supercapacitor electrode composite materials.

[0085] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A CS / NiCo-CH composite electrode material, characterized in that, It includes a CS matrix and a nickel-cobalt-based hydroxide compounded with the CS matrix; the CS matrix is ​​prepared by a carbonization process of pyromellitic dianhydride.

2. The CS / NiCo-CH composite electrode material according to claim 1, characterized in that, The specific surface area of ​​the composite electrode material is ≥1800 m². 2 ·g -1 Specific capacitance ≥ 650 F·g -1 After 5000 cycles, the capacitance retention is ≥94%, and the energy density is ≥50Wh·kg. -1 .

3. A method for preparing the CS / NiCo-CH composite electrode material according to claim 1, characterized in that, Includes the following steps: Step 1: Place pyromellitic dianhydride in an inert gas protective atmosphere, heat to the carbonization temperature and maintain the temperature, then cool, grind and sieve to obtain the CS matrix; Step 2: Disperse the CS matrix in ultrapure water, and prepare a precipitate-free suspension by stirring and ultrasonic treatment; add nickel salt, cobalt salt and urea to the suspension, and continue stirring and ultrasonic treatment until the solid is completely dissolved to form a homogeneous mixture; Step 3: Transfer the homogeneous mixture to a high-pressure reactor for hydrothermal reaction. After the hydrothermal reaction is completed, allow the reactor to cool naturally to room temperature. Step 4: Filter the solid-liquid mixture in the cooled reactor to obtain a solid product; wash the solid product with ultrapure water until the pH of the filtrate is neutral; vacuum dry the washed solid product, grind it, and sieve it to obtain the CS / NiCo-CH composite electrode material.

4. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 1, during the preparation of the CS matrix, pyromellitic dianhydride is placed in a high-temperature alumina crucible and calcined before carbonization, and the inert gas is high-purity argon.

5. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 1, the carbonization temperature is 1050-1150℃, and the temperature is maintained for 5.5-6.5 hours, followed by passing through a 200-mesh sieve.

6. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 2, the cobalt salt is cobalt chloride hexahydrate, and the nickel salt is nickel chloride hexahydrate.

7. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 2, during the process of forming a homogeneous mixture, the ultrasonic treatment time is 50-60 minutes.

8. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 3, the high-pressure reactor is a polytetrafluoroethylene-lined high-pressure reactor; the hydrothermal reaction temperature is 100-105℃ and the time is 22-24h.

9. The method for preparing a CS / NiCo-CH composite electrode material according to claim 3, characterized in that, In step 4, a circulating vacuum pump is used for filtration; a vacuum drying oven is used for vacuum drying at a temperature of 65-70℃; after drying, the material is ground in an agate mortar at a grinding rate of 150-200 r / min and then passed through a 200-mesh sieve.

10. A supercapacitor, characterized in that, The electrodes of the supercapacitor comprise the CS / NiCo-CH composite electrode material as described in claim 1.

Images