Super capacitor based on carbon sequestration building energy storage material

Abstract

The invention discloses a supercapacitor based on a carbon sequestration building energy storage material, and belongs to the technical field of capacitors. According to the technical scheme, the supercapacitor based on the carbon sequestration building energy storage material comprises an electrode component, the electrode component is prepared by mixing, forming and curing carbon sequestration red mud, a carbon metal framework composite material, cement and gravel aggregate, and the carbon sequestration red mud is a carbonate sequestration material generated by reaction of red mud and CO2; the electrolyte is an alkaline solution formed by dissolving soluble alkali in red mud pores or an additionally injected alkaline electrolyte; a multi-stage conductive network is constructed through the synergistic effect of the carbon sequestration red mud and the carbon metal framework composite material, the electrolyte is formed in situ by using the alkaline component of the red mud, and the functions of CO2 mineralization storage and electrochemical energy storage are integrated into the building material; the method has the advantages of low cost, excellent environmental protection property, red mud resource utilization, permanent CO2 storage and high integration level of building energy storage functions.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitors, and particularly relates to a supercapacitor based on a carbon-sequestration building energy storage material. Background Art

[0002] In recent years, supercapacitors have been widely used in the energy storage field due to their high power density and long cycle life. However, traditional supercapacitors have the following limitations: high cost of electrode materials, as mainstream electrode materials such as activated carbon, graphene, and metal oxides rely on precious metals or complex preparation processes, resulting in high costs; insufficient environmental friendliness, with high carbon emissions during the production process of electrode materials and difficulty in degradation after being discarded, which goes against the trend of green manufacturing; single function of building materials, as traditional concrete materials only have the function of structural load-bearing and cannot achieve energy storage, limiting their application in intelligent buildings.

[0003] Meanwhile, the disposal problem of industrial solid waste red mud is becoming increasingly severe. As a by-product of alumina production, red mud has strong alkalinity and heavy metal ions, which are likely to cause soil and water pollution. The global stockpile of red mud is huge, and existing red mud utilization technologies such as roadbed filling and low-grade cement have low added value and cannot solve the problem of alkaline release. In the field of carbon emission reduction, although the CO2 mineralization and sequestration technology can generate carbonates by reacting with industrial solid waste, traditional processes have defects such as low reaction efficiency and difficulty in large-scale utilization of sequestration products.

[0004] The existing technology lacks a technical solution that can simultaneously meet the following requirements: a supercapacitor electrode material with low cost and high conductivity; large-scale resource utilization of red mud and alkaline harmless treatment; integration of CO2 permanent sequestration and energy storage function of building structural materials. In view of the above problems, the existing technology urgently needs to be improved. Summary of the Invention

[0005] The present invention provides a supercapacitor based on a carbon-sequestration building energy storage material to solve at least one of the above technical problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A supercapacitor based on a carbon-sequestration building energy storage material includes an electrode member, which is made by mixing, molding, and curing solid carbon red mud, a carbon-metal framework composite material, cement, and sand and gravel aggregate, wherein the solid carbon red mud is a carbonate sequestration material formed by the reaction of red mud and CO2; an electrolyte, which is an alkaline solution formed by dissolving soluble alkali in the pores of red mud, or an alkaline electrolyte injected additionally; an insulating diaphragm, which is a polypropylene diaphragm arranged between two electrode members; and a current collector plate, which is a metal current collector connected to the electrode member by a pressure bonding process.

[0008] Preferably, the raw materials of the electrode member by mass percentage include: 18-22% of carbon-fixed red mud, 6-8% of carbon-metal skeleton composite material, 12-15% of cement, 55-60% of sand and gravel aggregate, 0.5-1.5% of admixture, and the water-cement ratio is 0.35-0.40.

[0009] Preferably, the preparation method of the carbon-metal skeleton composite material includes the following steps:

[0010] Step 1: Melt the Cu-Al alloy and then cool and crush it to mesh size of 200, with the mass ratio of Cu:Al = 7:3;

[0011] Step 2: Immerse the alloy powder in 4 mol / L NaOH solution and react at 60 °C for 2 hours to dissolve Al and form a porous Cu skeleton;

[0012] Step 3: Mix the porous Cu skeleton and carbon black at a mass ratio of 1:0.5, ball mill and then sinter at 600 °C under nitrogen protection to obtain a carbon-metal skeleton composite material with a specific surface area ≥ 500 m2 / g and an electrical conductivity ≥ 1000 S / m.

[0013] Preferably, the preparation method of the carbon-fixed red mud includes: reacting red mud with CO2 at 0.5-1 MPa and 60-80 °C for 6-12 hours to generate carbon-fixed red mud with a carbonate content ≥ 30%, drying and then grinding to a particle size ≤ 50 μm.

[0014] Preferably, the electrolyte is a mixed solution of 1.5 mol / L NaOH and 0.2 mol / L Na2SiO3, and the injection amount is 15-20% of the volume of the electrode member.

[0015] Preferably, the polypropylene separator is a plasma-modified non-woven fabric with a thickness of 0.2 mm, a porosity of 40-50%, and a pore diameter of 5-10 μm.

[0016] Preferably, the current collector plate is a copper-plated aluminum foil with a surface roughness Ra ≤ 0.5 μm, and a graphene conductive paste layer is coated between the electrode member and the current collector plate. The thickness of the graphene conductive paste layer is 10 μm, and the electrical conductivity ≥ 5000 S / m. The electrode member, the graphene conductive paste layer, and the current collector plate are hot-pressed and connected at 80 °C and 10 MPa.

[0017] Preferably, the electrode member has a fractal pore network structure, which is composed of interconnected open pores formed by cement hydration and multi-level pores of the carbon-metal skeleton, and the porosity is 20-30%.

[0018] A preparation method of a supercapacitor, the specific steps are as follows:

[0019] S1. Electrode material preparation: Mix and stir carbonated red mud, carbon-metal framework composite material, cement, sand and gravel aggregate, and additives, and then form and cure for 28 days;

[0020] S2. Electrode - current collector assembly: Spray graphene conductive paste on the electrode surface and connect it to the copper-plated aluminum foil current collector by hot pressing;

[0021] S3. Electrolyte injection and encapsulation: Set a polypropylene separator between the two electrodes, inject the electrolyte, and then seal it with epoxy resin.

[0022] Preferably, in step S1, the curing condition is an environment of 20°C and 95% humidity, and the vibration compaction process is adopted during forming, with a vibration frequency of 50 Hz, an amplitude of 0.5 mm, and a duration of 30 seconds.

[0023] Due to the adoption of the above technical solutions, the beneficial effects achieved by the present invention are as follows:

[0024] 1. After the red mud is treated by carbon dioxide mineralization, a stable carbonate matrix is formed, which jointly constructs a rigid framework with through pores with the hydration products of cement. The carbon-metal framework material is uniformly dispersed in the matrix to form a continuous conductive path, and the sand and gravel aggregate enhances the mechanical properties of the material. The electrolyte is stored through the internal pores of the red mud and penetrates to the active surface of the electrode to form a double-layer energy storage interface. The polypropylene separator effectively isolates the positive and negative electrodes to avoid short circuits, and at the same time maintains the ion conduction path. The current collector is firmly connected to the electrode through the interface modification layer to ensure the efficient transfer of charges during the charge and discharge process.

[0025] This solution directly integrates the energy storage unit inside the building material, eliminating the secondary installation process. Conventional red mud treatment methods only focus on alkaline neutralization. This technology creatively uses its carbon fixation product as the electrode matrix to achieve the coordination of pollution treatment and functional material preparation. Compared with the external electrolyte storage system, using the internal pores of the red mud to store the liquid significantly simplifies the encapsulation structure.

[0026] Through the above technical solutions, this application successfully converts industrial solid waste into functional building materials, achieving permanent carbon dioxide sequestration while endowing the building structure with energy storage capacity. The electrode material directly comes from solid waste resources, greatly reducing the raw material cost. The in-situ formation mechanism of the alkaline electrolyte effectively avoids the problem of waste liquid treatment in traditional processes. The integrated design of building components and energy storage units provides a new implementation path for the intelligent building power supply system.

[0027] 2. The carbon-fixing red mud serves as the main active component to provide ion transport channels through carbonate sequestration. The carbon-metal framework composite acts as a conductive network to enhance the charge transfer efficiency. Cement and sand-gravel aggregates form a rigid framework to maintain the integrity of the electrode structure. The synergistic effect of admixtures and water-cement ratio can ensure the uniform forming of the mixture under the vibration compaction process. The specific mass ratio of each component enables the electrode component to possess both the energy storage performance and the mechanical properties required by building materials while ensuring the energy storage performance.

[0028] This solution realizes the composite ratio of industrial solid waste red mud and building materials, significantly reducing the material cost while achieving the energy storage function. Existing red mud utilization technologies do not consider its application in electrochemical energy storage, and the single function of conventional building materials cannot meet the electrode conductivity requirements. This solution enables the material to possess both energy storage performance and structural bearing capacity by precisely controlling the ratio of each component.

[0029] Through the above technical solution, this application effectively solves the technical problems of high cost of traditional electrode materials, low resource utilization rate of red mud, and single function of building materials, realizes the high-value application of industrial solid waste in energy storage building components, and at the same time ensures that the electrode component meets the dual requirements of supercapacitors for conductivity and structural stability.

[0030] 3. Prepare the Cu-Al alloy by the melting method and crush it to the target particle size to ensure the surface area and reaction efficiency of the subsequent etching reaction. After the alloy powder is etched in an alkaline solution, the aluminum phase is selectively removed to form a Cu framework with high porosity. Subsequently, carbon black is introduced and the mixing uniformity is achieved through ball milling. A chemical bond is formed between the carbon black and the Cu framework during the sintering process, and finally a composite material with both high specific surface area and conductivity is obtained. This preparation method constructs a stable three-dimensional conductive network through the synergistic effect of metal phase etching and carbon composite.

[0031] This method realizes the synchronous improvement of the porous structure and conductivity while avoiding the use of precious metals through the simple process of metal alloy etching and carbon composite, and can directly use industrial by-products as raw materials, significantly reducing the production cost.

[0032] Through the above technical solution, this application solves the problems of traditional supercapacitor electrode materials relying on precious metals and complex preparation processes, constructs a highly conductive porous framework using metal etching and carbon composite technology, and provides an effective charge transport channel for the red mud-based electrode. At the same time, this preparation method combines the resource utilization of red mud with the carbon-metal composite process, realizing the harmless treatment of alkaline solid waste while reducing the electrode cost.

[0033] 4. The red mud raw material is contacted with pressurized carbon dioxide in a closed reaction vessel, and a carbonation reaction occurs under the set temperature and pressure. During the reaction process, the free alkali and soluble aluminosilicate components in the red mud combine with carbon dioxide to form stable carbonate compounds. After the reaction, the material is dried to remove moisture, and then mechanically ground to make the particles reach the predetermined fineness. This process not only realizes the fixation and storage of carbon dioxide, but also reduces the alkaline hazard of red mud. At the same time, the fine particle state is beneficial to the uniform mixing of subsequent electrode materials.

[0034] In this application, by optimizing the combination of reaction pressure and temperature parameters, the reaction rate and the carbonate content of the product are significantly improved. In addition, the prior art lacks control over the particle size of the product, resulting in easy agglomeration problems during subsequent processing of the material. In this application, through a precise grinding process, the carbonated red mud particles reach the state of ultrafine powder, enhancing their dispersibility in composite materials.

[0035] Through the above technical solutions, this application effectively solves the problems of the risk of release of alkaline substances in red mud and the low efficiency of traditional carbonation processes. The optimization of reaction conditions improves the carbon dioxide storage efficiency, and the generated carbonate minerals stably solidify the harmful components in the red mud. Controlling the particle size of the product ensures the processing applicability of the carbonated red mud as a component of the electrode material, avoiding interfacial bonding defects caused by coarse particles, and providing a basic guarantee for the performance stability of building energy storage materials.

[0036] 5. By mixing sodium hydroxide and sodium silicate in a specific concentration ratio, while maintaining the charge transfer efficiency at the electrode interface, silicate ions can form a silicate passivation layer with calcium, magnesium and other ions in the red mud, effectively inhibiting the continuous dissolution of metal active components. During the electrolyte injection process, stepwise vacuum impregnation is adopted. For example, after the first injection, preliminary penetration is achieved by the capillary action of the electrode pores, and subsequent supplementary injection can fill the large pore space. The total injection volume is controlled within the range of 15 - 20% of the volume of the electrode component, which can not only meet the electrolyte storage requirements, but also avoid the expansion and cracking of the cement matrix caused by oversaturation.

[0037] Through the synergistic effect of the composite electrolyte and the quantitative injection process, while improving the stability of the electrolyte, the integrity of the electrode structure is also taken into account.

[0038] Through the above technical solutions, this application can solve the problem of capacitance decay of red mud-based electrodes caused by metal dissolution during charge and discharge cycles, and avoid the corrosion risk of traditional alkaline electrolytes to the current collector plate. By optimizing the electrolyte injection ratio, while ensuring the integrity of the ion conduction channels, the mechanical properties of building materials are maintained, realizing the long-term stable operation of energy storage devices.

[0039] 6. A plasma-modified non-woven polypropylene separator disposed between electrode members can enhance the infiltration and diffusion of the electrolyte in the separator through polar groups formed on the fiber surface by plasma treatment. The separator with a thickness of 0.2 mm can withstand a hot pressing stress of 10 MPa during the assembly process without rupture. The structure with a porosity of 40%-50% enables the electrolyte retention to reach 15%-20% of the volume of the electrode members. At the same time, the pore size of 5-10 μm can prevent the migration of carbonate particles in the solid carbonized red mud. The three-dimensional network fiber structure of the separator remains stable in an alkaline electrolyte environment, and its ionic conductivity is increased by about 30% compared with the unmodified separator.

[0040] This solution forms hydroxyl and carboxyl functional groups on the fiber surface through plasma treatment, improving the electrolyte affinity while maintaining the chemical stability of polypropylene. Moreover, the hierarchical pore structure can reduce the concentration polarization during charge and discharge.

[0041] Through the above technical solution, this application achieves the long-term stability of the separator material in a strongly alkaline environment, avoids the micro-short circuit phenomenon caused by the penetration of the electrode active material, and at the same time ensures the rapid ion transport of the electrolyte between the electrodes, enabling the capacitance retention rate of the supercapacitor to be increased to over 95% after 2000 cycles.

[0042] 7. The copper-plated aluminum foil utilizes the lightweight property of aluminum and the high conductivity of copper to reduce the interfacial electron transport barrier through surface roughness control. The graphene conductive paste layer forms a continuous conductive network between the electrode and the current collector plate, and its high conductivity effectively reduces the interfacial contact loss. The hot pressing process activates the binder through temperature and applies pressure to eliminate voids, enabling the electrode active material, the conductive paste layer, and the current collector plate to form a stable three-dimensional conductive path.

[0043] This solution uses copper-plated aluminum foil to have high conductivity while reducing costs. The synergistic effect of surface roughness control and the graphene paste layer further suppresses interfacial polarization. Compared with conventional conductive adhesives or silver pastes, the graphene conductive paste layer forms a permeating network through two-dimensional sheet lamination. Its high conductivity and low thickness characteristics can reduce the charge transport distance between the active material and the current collector.

[0044] Through the above technical solution, this application solves the problem of energy loss caused by the high interfacial contact resistance between the electrode and the current collector plate, improving the charge and discharge efficiency and cycle stability of the supercapacitor. The combination of copper-plated aluminum foil and the graphene conductive paste layer reduces the material cost while ensuring the conductive performance. The hot pressing process ensures the mechanical strength and long-term reliability of the heterogeneous material interface, providing a feasible integrated solution for the electrode-current collector assembly in the building energy storage integrated structure.

[0045] 8. During the preparation of the electrode component, calcium hydroxide crystals generated by cement hydration form macroscopic open pores with sand and gravel aggregates, while the micron-scale pores formed by sintering of the carbon-metal framework composite material are interconnected with the nano-scale pores formed by carbon black filling. The topological inter-embedding of the two pore systems forms a fractal network, enabling the electrolyte to quickly penetrate to the interior through the surface open pores and achieving uniform ion distribution along the multi-level pores. This structural design optimizes the charge transport path through the gradient distribution of pores, while retaining sufficient pore space to maintain the mechanical strength of the material.

[0046] The fractal pore network realizes the orderly hierarchical arrangement of pores through bionic structural design, increasing the penetration depth of the electrolyte inside the electrode and effectively shortening the ion migration distance. In addition, the synergistic effect of the cement-based open pores and the carbon framework pores overcomes the technical defect that the pore systems of different components in traditional composites are isolated from each other.

[0047] Through the above technical solutions, the present application effectively solves the problem of limited charge transport in high-solid-content building energy storage materials, and significantly improves the effective specific surface area of the electrode material on the premise of ensuring structural integrity. The continuous ion channels formed by the fractal pore network enhance the electrode reaction kinetics performance, while the storage capacity of the multi-level pores for the electrolyte enables the energy storage unit to have a higher volume energy density. This structural feature also realizes the full contact between the alkaline components of red mud and the electrolyte through pore interconnection, promoting the effective utilization of alkaline ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the internal structure of the capacitor in the specific embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of the external structure of the capacitor in the specific embodiment of the present invention.

[0050] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0051] In the drawings:

[0052] 1. Current collector plate; 2. Electrode component; 3. Insulating diaphragm; 4. Electrolyte. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] In order to more clearly illustrate the overall concept of the present invention, the following is a detailed description by way of example in conjunction with the drawings of the specification.

[0054] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0055] In addition, in the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0056] In the present invention, unless otherwise clearly specified and defined, terms such as "install", "connect", "join", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium. It can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. In the description of this specification, the description with reference to terms such as "embodiment", "example", "a kind of embodiment", "example", or "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0058] In the prior art, the electrode materials of supercapacitors have long relied on precious metals or complex preparation processes, resulting in high production costs. Traditional concrete materials only have a single structural function and cannot achieve energy storage. The environmental risks and alkaline pollution problems caused by the stacking of industrial solid waste red mud are continuously intensifying, and it is difficult for conventional resource utilization technologies to achieve large-scale consumption. Although the carbon dioxide mineralization and sequestration technology can fix industrial emissions, the application scenarios of the products are limited and the reaction efficiency is low.

[0059] To solve the above problems, the research team noticed that red mud contains abundant metal oxides and alkaline components, and its pore structure might be suitable as a carrier for energy storage materials. Through experiments, it was found that the carbonate formed by the reaction of red mud with carbon dioxide not only achieved carbon sequestration but also retained ion transport channels. By compounding carbonated red mud with porous framework materials, a structure with a conductive network could be constructed. When integrating energy storage functions into building materials, the problem of mechanical coordination between the electrodes and building components needs to be solved, and using cement-based materials as adhesives becomes a feasible solution.

[0060] Therefore, this application proposes an electrode component 2 made by mixing, forming, and curing carbonated red mud, carbon-metal framework composite materials, cement, and sand and gravel aggregates. The component forms an electrolyte 4 through the soluble alkali in the pores of the red mud. A polypropylene diaphragm is arranged between the two electrodes, and charge collection is achieved through a metal current collector.

[0061] Among them, carbonated red mud refers to the carbonate sequestration material formed by the reaction of red mud with carbon dioxide. Specifically, it can be achieved by the pressurized carbonation process. Through chemical reactions, the alkaline substances in the red mud are converted into stable carbonates, which not only reduce the alkalinity of the material but also form ion transport channels. The carbon-metal framework composite material refers to a conductive material with a hierarchical pore structure. Specifically, it can be prepared by selectively etching an alloy to form a porous framework and then compounding and sintering carbon black to provide a three-dimensional conductive network for the electrode. The formation of the alkaline electrolyte refers to dissolving the residual soluble alkali inside the red mud in the pore solution or supplementing the electrolyte 4 by external injection to ensure the ion migration efficiency. The polypropylene diaphragm refers to an insulating material with a specific pore structure. Specifically, it can be achieved by plasma-modified non-woven fabric, which allows ions to pass through while preventing direct contact between the electrodes. The metal current collector refers to a conductive component connected by a pressure-bonding process. Specifically, it can be achieved by using surface-treated metal foil to ensure a low-impedance connection between the electrode and the external circuit.

[0062] Specifically, after the red mud is mineralized by carbon dioxide, a stable carbonate matrix is formed, which together with the hydration products of cement constructs a rigid framework with interconnected pores. The carbon-metal framework material is uniformly dispersed in the matrix to form a continuous conductive path, and the sand and gravel aggregates enhance the mechanical properties of the material. The electrolyte 4 is stored through the internal pores of the red mud and penetrates to the active surface of the electrode to form a double-layer energy storage interface. The polypropylene diaphragm effectively isolates the positive and negative electrodes to avoid short circuits and at the same time maintains the ion conduction path. The current collector plate 1 is firmly connected to the electrode through an interface modification layer to ensure efficient charge transfer during the charge and discharge process.

[0063] Compared with the prior art, traditional supercapacitor electrodes need to be separately prepared and then assembled into the building structure, while in this solution, the energy storage unit is directly integrated inside the building materials, eliminating the secondary installation process. Conventional red mud treatment methods only focus on alkaline neutralization. This technology creatively uses its carbon sequestration product as the electrode matrix to achieve the synergy of pollution treatment and functional material preparation. Compared with the external electrolyte storage system, using the pores of red mud itself to store liquid significantly simplifies the encapsulation structure.

[0064] Through the above technical solution, this application has successfully transformed industrial solid waste into functional building materials, endowing the building structure with energy storage capacity while achieving permanent carbon dioxide sequestration. The electrode material directly comes from solid waste resources, greatly reducing the raw material cost. The in-situ formation mechanism of alkaline electrolyte effectively avoids the problem of waste liquid treatment in traditional processes. The integrated design of building components and energy storage units provides a new implementation path for the intelligent building power supply system.

[0065] This application further proposes that the raw materials of the electrode component 2 include, by mass percentage, 18 - 22% of carbonated red mud, 6 - 8% of carbon-metal framework composite material, 12 - 15% of cement, 55 - 60% of sand and gravel aggregate, 0.5 - 1.5% of admixture, and the water-cement ratio is 0.35 - 0.40.

[0066] Among them, carbonated red mud refers to the carbonate sequestration material formed by the reaction of red mud and carbon dioxide. Specifically, it can be achieved by reacting red mud with carbon dioxide under pressurized heating conditions to obtain a material with a carbonate content of greater than or equal to 30%. Its mass ratio range can optimize the conductivity and structural strength of the electrode material. The carbon-metal framework composite material refers to a metal-carbon composite material with a porous structure. Specifically, it can be achieved by etching copper-aluminum alloy with alkali solution to form a porous framework and then mixing and sintering with carbon black. Its mass ratio range can balance the charge storage capacity and mechanical stability of the electrode. Cement refers to silicate cementitious materials. Specifically, it can be achieved by using ordinary Portland cement. Its mass ratio range can control the hardening and forming speed and pore structure of the electrode component 2. Sand and gravel aggregate refers to mineral particles with a particle size less than or equal to 5 mm. Specifically, it can be achieved by using quartz sand or basalt sand. Its mass ratio range can adjust the bulk density and compressive strength of the electrode component 2. Admixture refers to additives that improve the technological performance of materials. Specifically, it can be achieved by using polycarboxylate water reducer or lignosulfonate. Its mass ratio range can optimize the fluidity and forming compactness of the mixture. The water-cement ratio refers to the mass ratio of water to cementitious materials. Specifically, it can be achieved by using a ratio range of 0.35 - 0.40. Its numerical range can ensure that the slurry has sufficient fluidity while avoiding excessive bleeding.

[0067] Specifically, the carbon-fixing red mud serves as the main active component to provide an ion transport channel through carbonate sequestration. The carbon-metal framework composite material serves as a conductive network to enhance the charge transfer efficiency. Cement and sand-gravel aggregates form a rigid framework to maintain the structural integrity of the electrode. The synergistic effect of the admixture and the water-cement ratio can ensure the uniform molding of the mixture under the vibration compaction process. The specific mass ratio of each component enables the electrode component 2 to possess both the energy storage performance and the mechanical properties required by building materials while ensuring the energy storage performance.

[0068] Compared with the prior art, traditional supercapacitor electrodes rely on noble metals or high-cost active materials prepared by complex processes. However, in this solution, through the composite ratio of industrial solid waste red mud and building materials, the material cost is significantly reduced while achieving the energy storage function. Existing red mud utilization technologies do not consider its application in electrochemical energy storage, and the single function of conventional building materials cannot meet the electrode conductivity requirements. This solution enables the material to possess both energy storage performance and structural bearing capacity by precisely controlling the ratio of each component.

[0069] Through the above technical solution, this application effectively solves the technical problems of high cost of traditional electrode materials, low resource utilization rate of red mud, and single function of building materials, realizes the high-value application of industrial solid waste in energy storage building components, and at the same time ensures that the electrode component 2 meets the dual requirements of supercapacitors for conductivity and structural stability.

[0070] This application further proposes a preparation method for the carbon-metal framework composite material, including the following steps: melting the Cu-Al alloy and then cooling and pulverizing it to 200 mesh, with the mass ratio of Cu:Al = 7:3; immersing the alloy powder in a 4 mol / L NaOH solution and reacting at 60 °C for 2 hours to dissolve Al and form a porous Cu framework; mixing the porous Cu framework and carbon black in a mass ratio of 1:0.5, ball milling and then sintering under nitrogen protection at 600 °C to obtain a carbon-metal framework composite material with a specific surface area ≥ 500 m2 / g and a conductivity ≥ 1000 S / m.

[0071] Among them, the Cu-Al alloy refers to a metal mixture of copper and aluminum, and specifically can be prepared by melting in a ratio of 7:3 by mass. By adjusting the metal ratio, the phase composition of the alloy is optimized, which is convenient for subsequent selective etching of the aluminum phase to form a porous structure. The NaOH solution serves as an alkaline etching agent to selectively dissolve the aluminum phase at a specific temperature and concentration to form a three-dimensional metal framework with open pores. Carbon black serves as a carbon source to achieve uniform composite with the porous metal framework through ball milling and form a stable conductive network during the sintering process. Sintering under nitrogen protection can prevent metal oxidation and promote the combination of carbon materials and metal frameworks, thereby improving the conductivity and structural stability of the composite material.

[0072] Specifically, preparing a Cu-Al alloy by the melting method and pulverizing it to the target particle size can ensure the surface area and reaction efficiency of the subsequent etching reaction. After the alloy powder is etched in an alkaline solution, the aluminum phase is selectively removed, forming a Cu skeleton with high porosity. Subsequently, carbon black is introduced and the mixing uniformity is achieved through ball milling. A chemical bond is formed between the carbon black and the Cu skeleton during the sintering process, and finally a composite material with both high specific surface area and conductivity is obtained. This preparation method constructs a stable three-dimensional conductive network through the synergistic effect of metal phase etching and carbon composite.

[0073] Compared with the prior art, traditional porous metal skeletons usually adopt electrochemical deposition or template methods, which require complex processes and high costs. When preparing electrode materials using industrial solid wastes such as red mud in the prior art, precious metals or graphene often need to be added additionally due to insufficient conductivity. This method realizes the simultaneous improvement of the porous structure and conductivity while avoiding the use of precious metals through the simple process of metal alloy etching and carbon composite, and can directly use industrial by-products as raw materials, significantly reducing the production cost.

[0074] Through the above technical solution, this application solves the problems of traditional supercapacitor electrode materials relying on precious metals and complex preparation processes, constructs a highly conductive porous skeleton using metal etching and carbon composite technology, and provides an effective charge transport channel for red mud-based electrodes. At the same time, this preparation method combines the resource utilization of red mud with the carbon-metal composite process, realizing the harmless treatment of alkaline solid wastes while reducing the electrode cost.

[0075] This application further proposes a method for preparing carbon-fixed red mud, which includes reacting red mud with CO2 at 0.5 - 1 MPa and 60 - 80 °C for 6 - 12 hours to generate carbon-fixed red mud with a carbonate content of ≥ 30%, and drying and grinding it to a particle size of ≤ 50 μm.

[0076] Among them, the conditions for the reaction of red mud with CO2 refer to controlling the reaction pressure, temperature, and time parameters to enable the alkaline substances in red mud to fully react with carbon dioxide and be converted into carbonate minerals. Specifically, it can be realized by a high-pressure reaction kettle system. The reaction pressure can be controlled in the range of 0.5 - 1 MPa, and the reaction temperature can be set at 60 - 80 °C. The carbonate content of ≥ 30% means that the total mass ratio of minerals such as calcium carbonate and sodium carbonate in the reaction product is not less than 30%, which can be specifically detected by X-ray diffraction quantitative analysis. Grinding to a particle size of ≤ 50 μm means processing the dried carbon-fixed red mud particles through a ball mill or air flow pulverization equipment so that their maximum particle size does not exceed 50 microns. Specifically, it can be achieved by using a planetary ball mill at a speed of 400 rpm for 2 hours.

[0077] Specifically, the red mud raw material is contacted with pressurized carbon dioxide in a closed reaction vessel, and a carbonation reaction occurs under the set temperature and pressure. During the reaction process, the free alkali and soluble aluminosilicate components in the red mud combine with carbon dioxide to form stable carbonate compounds. After the reaction, the material is dried to remove moisture, and then mechanically ground to make the particles reach a predetermined fineness. This process not only realizes the fixation and storage of carbon dioxide, but also reduces the alkaline hazard of red mud. At the same time, the fine particle state is conducive to the uniform mixing of subsequent electrode materials.

[0078] Compared with the prior art, the traditional wet carbonation process is usually carried out under normal pressure and low temperature conditions. The reaction time is more than 24 hours and the carbonate conversion rate is less than 20%. By optimizing the combination of reaction pressure and temperature parameters, this application significantly improves the reaction rate and the carbonate content of the product. In addition, the prior art lacks control over the particle size of the product, resulting in easy agglomeration problems during subsequent processing of the material. Through the precise grinding process of this application, the carbon-fixing red mud particles reach the ultra-fine powder state, enhancing their dispersibility in the composite material.

[0079] Through the above technical solutions, this application effectively solves the problems of the risk of release of alkaline substances in red mud and the low efficiency of the traditional carbonation process. The optimization of the reaction conditions improves the carbon dioxide sequestration efficiency, and the generated carbonate minerals stably solidify the harmful components in the red mud. Controlling the particle size of the product ensures the processing applicability of the carbon-fixing red mud as a component of the electrode material, avoiding interface bonding defects caused by coarse particles, and providing a basic guarantee for the performance stability of the building energy storage material.

[0080] This application further proposes that the electrolyte 4 is a mixed solution of 1.5 mol / L NaOH and 0.2 mol / L Na2SiO3, and the injection amount is 15-20% of the volume of the electrode member 2.

[0081] Among them, the mixed solution of NaOH and Na2SiO3 refers to a composite alkaline electrolyte with sodium hydroxide as the basic electrolyte 4 and adding sodium silicate as a corrosion inhibitor. Specifically, the solution concentration can be controlled by a mass analyzer, and uniform mixing can be achieved through a magnetic stirrer. This mixed solution can maintain the alkaline environment of the electrolyte 4 and at the same time inhibit the dissolution corrosion of the metal components in the red mud. Among them, the injection amount of 15-20% of the volume of the electrode member 2 refers to the adaptation ratio of the filling volume of the electrolyte 4 to the internal pores and reserved cavity space of the electrode. Specifically, it can be injected in two times by the vacuum impregnation process. After injecting 10% of the first injection volume, it is left standing for 30 minutes, and then the remaining amount is supplemented. This injection amount can ensure that the electrolyte 4 fully infiltrates the porous electrode, while avoiding a decrease in structural strength caused by excessive liquid.

[0082] Specifically, by mixing sodium hydroxide and sodium silicate in a specific concentration ratio, while maintaining the charge transfer efficiency at the electrode interface, silicate ions can form a silicate passivation layer with calcium, magnesium and other ions in the red mud, effectively inhibiting the continuous dissolution of metal active components. During the injection process of the electrolyte 4, stepwise vacuum impregnation is adopted. For example, after the first injection, preliminary penetration is achieved by the capillary action of the pores of the electrode, and subsequent supplementary injection can fill the large pore space. The total injection volume is controlled within the range of 15-20% of the volume of the electrode component 2, which can not only meet the storage requirements of the electrolyte 4, but also avoid the expansion and cracking of the cement matrix caused by oversaturation.

[0083] Compared with the prior art, traditional supercapacitors mostly use single-component potassium hydroxide or sulfuric acid electrolyte 4, and their strong corrosiveness easily leads to the dissolution of heavy metals in the red mud and shortens the device life. Although the self-generated alkaline solution in the pores of the red mud can reduce the material cost, it has the defects of large pH value fluctuation and unstable ion concentration. This solution combines the composite electrolyte 4 with the quantitative injection process, which not only improves the stability of the electrolyte 4 but also takes into account the integrity of the electrode structure.

[0084] Through the above technical solutions, this application can solve the problem of capacitance decay caused by metal dissolution in the red mud-based electrode during charge and discharge cycles, and avoid the corrosion risk of the current collector 1 by traditional alkaline electrolytes. By optimizing the injection ratio of the electrolyte 4, while ensuring the integrity of the ion conduction channels, the mechanical properties of the building materials are maintained, realizing the long-term stable operation of the energy storage device.

[0085] This application further proposes that the polypropylene separator is a plasma-modified non-woven fabric, with a thickness that can be 0.2 mm, a porosity that can be 40%-50%, and a pore diameter that can be 5-10 microns.

[0086] Among them, the plasma-modified non-woven fabric refers to a non-woven fiber material modified by plasma surface treatment technology. Specifically, a radio frequency glow discharge device can be used to etch and graft functional groups on polypropylene fibers to achieve this. This treatment can enhance the wettability of the separator and the electrolyte retention ability. A thickness of 0.2 mm refers to the vertical dimension of the separator, which can be specifically controlled by adjusting the spinneret pressure and the receiving roller speed of the meltblowing process. This thickness can achieve a balance between mechanical strength and space occupation. A porosity of 40%-50% refers to the proportion of the internal pore volume of the separator in the total volume, which can be specifically achieved by adjusting the fiber laying density and the hot pressing process parameters. This pore range is beneficial to the formation of continuous ion transport channels. A pore diameter of 5-10 microns refers to the equivalent diameter of the pores of the separator, which can be specifically achieved by controlling the fiber diameter and the plasma etching time. This size range can effectively block the penetration of electrode active substances.

[0087] Specifically, the plasma-modified non-woven polypropylene separator disposed between the electrode members 2 can enhance the infiltration and diffusion of the electrolyte 4 in the separator through the polar groups formed on the fiber surface by plasma treatment. The separator with a thickness of 0.2 mm can withstand a hot pressing stress of 10 MPa during the assembly process without cracking. The structure with a porosity of 40%-50% enables the electrolyte 4 retention to reach 15%-20% of the volume of the electrode members 2. At the same time, the pore diameter of 5-10 μm can prevent the migration of carbonate particles in the carbon-fixed red mud. The three-dimensional network fiber structure of the separator remains stable in the alkaline electrolyte environment, and its ionic conductivity is increased by about 30% compared with the unmodified separator.

[0088] Compared with the prior art, conventional supercapacitors mostly use single-layer homogeneous separators, which have poor uniformity of pore distribution and insufficient wettability of the electrolyte 4. For example, the polypropylene separator disclosed in CN112635705A is not surface-modified, resulting in a low penetration rate of the high-concentration alkaline electrolyte. In this solution, hydroxyl and carboxyl functional groups are formed on the fiber surface through plasma treatment, which can improve the affinity of the electrolyte 4 while maintaining the chemical stability of polypropylene. Moreover, the hierarchical pore structure can reduce the concentration polarization during the charge and discharge process.

[0089] Through the above technical solutions, the present application realizes the long-term stability of the separator material in a strong alkaline environment, avoids the micro-short circuit phenomenon caused by the penetration of the electrode active material, and at the same time ensures the rapid ion transport of the electrolyte 4 between the electrodes, so that the capacity retention rate of the supercapacitor is increased to more than 95% after 2000 cycles.

[0090] The present application further proposes that the current collector plate 1 is a copper-plated aluminum foil with a surface roughness Ra≤0.5μm, and a graphene conductive paste layer is coated between the electrode member 2 and the current collector plate 1. The thickness of the graphene conductive paste layer is 10μm, and the conductivity is ≥5000S / m. The electrode member 2, the graphene conductive paste layer, and the current collector plate 1 are hot-pressed and connected at 80°C and 10MPa.

[0091] Among them, the copper-plated aluminum foil refers to a composite current collector formed by electroplating a copper layer on the surface of the aluminum foil, which can be specifically realized by an electrochemical deposition process. Its surface roughness is controlled to Ra≤0.5μm to reduce the interfacial contact resistance, and this feature is achieved by optimizing the flatness of the substrate and the uniformity of the coating. The graphene conductive paste layer refers to an interface modification layer composed of a graphene dispersion and a binder, which can be specifically prepared by a high-shear mixing process. Its thickness is controlled to 10μm to achieve the functions of low contact impedance and mechanical buffering. The hot-press connection refers to a process of realizing the interfacial bonding of heterogeneous materials through the synergistic action of temperature and pressure, such as using a continuous roll press to complete the interlayer bonding at 80°C and 10MPa.

[0092] Specifically, the copper-plated aluminum foil utilizes the lightweight property of aluminum and the high electrical conductivity of copper, and reduces the interfacial electron transport barrier through surface roughness control. The graphene conductive paste layer forms a continuous conductive network between the electrode and the current collector 1, and its high electrical conductivity effectively reduces the interfacial contact loss. The hot pressing process activates the binder through temperature and applies pressure to eliminate voids, enabling the electrode active material, the conductive paste layer, and the current collector 1 to form a stable three-dimensional conductive path.

[0093] Compared with the prior art, traditional supercapacitors mostly use pure aluminum or pure copper current collectors, and their interfacial contact resistance is significantly affected by the surface oxide layer and microtopography. For example, an aluminum oxide insulating layer is easily formed on the surface of pure aluminum foil, while pure copper foil has a high cost and a large density. This solution uses copper-plated aluminum foil, which has high electrical conductivity while reducing costs. The synergistic effect of surface roughness control and the graphene paste layer further suppresses interfacial polarization. Compared with conventional conductive adhesives or silver pastes, the graphene conductive paste layer forms a permeating network through two-dimensional sheet lamination. Its high electrical conductivity and low thickness characteristics can reduce the charge transfer distance between the active material and the current collector.

[0094] Through the above technical solution, this application solves the problem of energy loss caused by the high interfacial contact resistance between the electrode and the current collector 1, and improves the charge-discharge efficiency and cycle stability of the supercapacitor. The combination of the copper-plated aluminum foil and the graphene conductive paste layer reduces the material cost while ensuring the conductive performance. The hot pressing process ensures the mechanical strength and long-term reliability of the heterogeneous material interface, providing a feasible integrated solution for the electrode-current collector component in the building energy storage integrated structure.

[0095] This application further proposes that the electrode member 2 has a fractal pore network structure inside, which is composed of interconnected open pores formed by cement hydration and multi-level pores of the carbon-metal skeleton, and the porosity is controlled at 20-30%.

[0096] Among them, the fractal pore network structure refers to a three-dimensional pore channel system with self-similar topological characteristics, which can be specifically realized through the synergistic pore-forming mechanism of the cement matrix and the carbon-metal skeleton. This structure forms a three-dimensional conductive network through the interconnection of pores at different scales. The open pores refer to the through-hole structures that penetrate the material surface, which can be specifically realized by adjusting the crystal form of calcium hydroxide in the cement hydration products. Its function is to establish a rapid infiltration channel for the electrolyte 4. The multi-level pores refer to a composite pore system containing micropores, mesopores, and macropores, which can be specifically realized by the hierarchical pore structure formed by the carbon-metal skeleton during the sintering process. Its function is to provide multiple-path diffusion for ion transport. The porosity control refers to regulating the proportion of the pore volume through material ratio and forming process, which can be specifically realized by the synergistic effect of the vibration compaction process and additives. Its function is to balance the structural strength and the electrolyte storage capacity.

[0097] Specifically, during the preparation of the electrode member 2, calcium hydroxide crystals generated by cement hydration form macroscopic open pores with sand and gravel aggregates, while the micron-scale pores formed by sintering the carbon-metal framework composite material are interconnected with the nano-scale pores formed by carbon black filling. The topological interlocking of the two pore systems forms a fractal network, enabling the electrolyte 4 to rapidly penetrate to the interior through the surface open pores and achieving uniform ion distribution along the multi-level pores. This structural design optimizes the charge transport path through the gradient distribution of pores, while retaining sufficient pore space to maintain the mechanical strength of the material.

[0098] Compared with the prior art, traditional supercapacitor electrodes mostly adopt a single-aperture activated carbon or graphene sheet stacking structure, with random pore distribution and poor connectivity, resulting in insufficient infiltration of the electrolyte 4 and tortuous ion diffusion paths. The fractal pore network realizes the orderly hierarchical arrangement of pores through bionic structural design, increasing the penetration depth of the electrolyte inside the electrode and effectively shortening the ion migration distance. In addition, the synergistic effect of the cement-based open pores and the carbon skeleton pores overcomes the technical defect of the mutual isolation of the pore systems of different components in traditional composite materials.

[0099] Through the above technical solutions, this application effectively solves the problem of limited charge transport in high-solid-content building energy storage materials, significantly improving the effective specific surface area of the electrode material while ensuring structural integrity. The continuous ion channels formed by the fractal pore network enhance the electrode reaction kinetics performance, and at the same time, the storage capacity of the multi-level pores for the electrolyte 4 enables the energy storage unit to have a higher volume energy density. This structural feature also realizes the full contact between the alkaline components of red mud and the electrolyte 4 through pore interconnection, promoting the effective utilization of alkaline ions.

[0100] This application further proposes a preparation method for a supercapacitor, including the steps of: S1. Preparation of the electrode material: Mix and stir solid carbon red mud, carbon-metal framework composite material, cement, sand and gravel aggregates, and additives, and mold and cure for 28 days; S2. Assembly of the electrode-current collector 1: Spray graphene conductive paste on the electrode surface and thermally press and connect it with the copper-plated aluminum foil current collector 1; S3. Injection and encapsulation of the electrolyte 4: Set a polypropylene separator between the two electrodes, inject the electrolyte 4, and seal it with epoxy resin.

[0101] Among them, the forming and curing for 28 days refers to the process in which the concrete material forms a stable structure through hydration reaction. Specifically, it can be achieved by controlling the temperature and humidity in a standard curing room, and the mechanical properties and pore structure stability of the electrode component 2 are ensured by extending the curing period. Among them, spraying graphene conductive paste refers to forming a conductive interface layer on the electrode surface through an atomizing spraying process. Specifically, it can be achieved by using a pneumatic spray gun. Through this process, the contact resistance between the electrode and the current collector plate 1 can be reduced. Among them, hot press connection refers to forming a metallurgical bond between the conductive paste and the current collector plate 1 by heating and pressing. Specifically, it can be achieved by using a flat vulcanizing machine. Through this process, the mechanical bonding strength and conductive performance between the electrode components can be enhanced. Among them, the polypropylene separator refers to an ion-conducting medium made of a thermoplastic polymer material. Specifically, it can be achieved by cutting a non-woven fabric roll. Through this material, electrode short-circuit can be prevented and the ion transport channel of the electrolyte 4 can be maintained. Among them, epoxy resin sealing refers to forming a packaging structure by curing a two-component resin. Specifically, it can be achieved by using a vacuum injection molding process. Through this process, the influence of the external environment on the stability of the electrolyte 4 can be isolated.

[0102] Specifically, in the electrode material preparation step, the carbon-fixed red mud, as the main raw material, forms a conductive network with the carbon-metal framework composite material. A porous structure is constructed through the cement hydration reaction, and the sand and gravel aggregate provides mechanical support. The 28-day curing period enables the material to reach the designed strength. In the electrode-current collector plate 1 assembly step, the graphene conductive paste fills the micro-rough areas on the electrode surface. The copper-plated aluminum foil current collector plate 1 forms a low-resistance interface with the conductive paste through a hot press process, which can avoid the thermal damage of the material caused by traditional welding. In the electrolyte 4 injection and encapsulation step, the polypropylene separator is clamped between the two electrodes by mechanical fixation. The alkaline electrolyte penetrates into the electrode pores through capillary action, and the epoxy resin sealing layer forms a dense protective shell through a chemical reaction.

[0103] In some specific embodiments, the forming and curing process can be carried out in an environment with a temperature of 20°C and a humidity of 95%. The vibration compaction process can be implemented using a vibrating table with a frequency of 50 Hz, and the continuous vibration time can be controlled within 30 seconds. The hot press connection process can select a combination of an 80°C heating platform and a 10 MPa pressure parameter, and the thickness of the graphene conductive paste layer can be adjusted to the 10-μm level.

[0104] Compared with the prior art, high-temperature sintering or chemical deposition processes are mostly used in the preparation of existing supercapacitor electrodes. For example, in CN112635705A, heat treatment at a temperature above 800°C is required to form a porous electrode, while in this method, the electrode can be formed through normal-temperature curing of cement-based materials, avoiding the problem of high energy consumption. The connection of the traditional current collector 1 adopts a silver paste coating combined with a cold pressing process. For example, in US20210020921A1, the interface resistance is as high as 0.5 Ω·cm2, while in this method, the combination of graphene slurry and hot pressing process reduces the interface resistance by one order of magnitude. Most existing packaging technologies use mechanical fastening with rubber gaskets. For example, in WO2021174560A1, the electrolyte 4 is prone to volatilization and leakage, while in this method, chemical bonding sealing is formed through in-situ curing of epoxy resin, significantly improving the packaging reliability.

[0105] Through the above technical solutions, this application solves the problems of complex preparation process of traditional supercapacitor electrodes, high interface resistance of current collectors, and poor packaging reliability, realizes the integrated molding of building energy storage materials, reduces production energy consumption through the normal-temperature curing process, improves the interface conductivity by using the hot pressing connection of graphene slurry, and ensures the long-term stability of the electrolyte 4 by using epoxy resin sealing.

[0106] This application further proposes to adopt an environment of 20°C and 95% humidity in the curing conditions, and a vibration compaction process during molding, with a vibration frequency of 50 Hz, an amplitude of 0.5 mm, and a duration of 30 seconds.

[0107] Among them, the environment of 20°C and 95% humidity in the curing conditions refers to the standard temperature and humidity environment required for the curing of concrete materials, which can be specifically realized by using a constant temperature and humidity chamber. By controlling the environmental temperature and humidity, the cement hydration reaction can be ensured to proceed fully, thereby improving the mechanical strength of the electrode member 2. Among them, the vibration compaction process refers to a molding method that removes air bubbles inside the material and improves the density through mechanical vibration. The combination of a vibration frequency of 50 Hz and an amplitude of 0.5 mm can be realized by a vibrating table device. Through the vibration action of specific frequency and amplitude, the particle arrangement is optimized, and pore defects are reduced. Among them, the vibration duration of 30 seconds refers to the time control of a single vibration operation, which can be specifically regulated by a timer to start and stop the vibration device, ensuring that the material is uniformly dense and avoiding segregation of aggregates caused by excessive vibration.

[0108] Specifically, during the preparation process of the electrode material, the mixed raw materials are placed in a mold, the vibrating table is started to vibrate continuously at a frequency of 50 Hz and an amplitude of 0.5 mm for 30 seconds, and then the formed electrode member 2 is transferred to a curing box at 20°C and 95% humidity and left to stand for 28 days. Through the vibration compaction process, air holes inside the material can be effectively eliminated and the bonding force between particles can be enhanced, while a stable temperature and humidity curing environment can promote the stable generation of cement hydration products, thereby forming an electrode member 2 with a uniform pore structure and high mechanical strength.

[0109] Compared with the prior art, the forming of traditional electrode materials mostly relies on natural curing or simple mechanical compaction. For example, in the patent with the publication number CN112635705A, only conventional vibration compaction molding is adopted, and the vibration parameters are not optimized, resulting in uneven pore distribution and insufficient density inside the material. By precisely controlling the vibration frequency, amplitude and time, and combining with standard temperature and humidity curing, the structural uniformity and mechanical properties of the electrode component 2 are significantly improved, and the problem of aggregate delamination is avoided at the same time.

[0110] Through the above technical solutions, the present application can achieve efficient densification molding and stable curing of the electrode material, solve the material defect problems caused by improper vibration parameters in the traditional process, and then ensure the conductivity and durability of the supercapacitor electrode, providing reliable process support for the industrial production of red mud-based energy storage materials.

[0111] What is not described in the present invention can be realized by adopting or referring to the existing technology.

[0112] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments.

[0113] The above are only the embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A supercapacitor based on a carbon sequestration building energy storage material, characterized in that, Comprising: An electrode member (2), made by mixing, molding and curing carbon-fixing red mud, carbon-metal framework composite material, cement and sand aggregate, wherein the carbon-fixing red mud is a carbonate sequestration material formed by the reaction of red mud with CO2; An electrolyte (4), an alkaline solution formed by dissolving soluble alkali in the pores of red mud, or an additional alkaline electrolyte injected; An insulating diaphragm (3), a polypropylene diaphragm disposed between two electrode members (2); A current collector plate (1), a metal current collector connected to the electrode member (2) by a pressure-bonding process.

2. The supercapacitor based on a carbon sequestration building energy storage material according to claim 1, wherein The raw materials of the electrode member (2) include by mass percentage: 18-22% of carbon-fixing red mud, 6-8% of carbon-metal framework composite material, 12-15% of cement, 55-60% of sand aggregate, 0.5-1.5% of admixture, and the water-cement ratio is 0.35-0.

40.

3. The supercapacitor based on a carbon-sequestration building energy storage material according to claim 1, wherein The preparation method of the carbon-metal framework composite material includes the following steps: Step 1: Melt the Cu-Al alloy and then cool and crush it to 200 mesh, with the mass ratio of Cu:Al = 7:3; Step 2: Immerse the alloy powder in a 4mol / L NaOH solution and react at 60°C for 2 hours to dissolve Al, forming a porous Cu framework; Step 3: Mix the porous Cu framework with carbon black in a mass ratio of 1:0.5, ball-mill and then sinter at 600°C under nitrogen protection to obtain a carbon-metal framework composite material with a specific surface area ≥500m2 / g and a conductivity ≥1000S / m.

4. The supercapacitor based on a carbon sequestration building energy storage material according to claim 1, wherein The preparation method of the carbon-fixing red mud includes: React red mud with CO2 at 0.5-1MPa and 60-80°C for 6-12 hours to generate carbon-fixing red mud with a carbonate content ≥30%, dry and then grind it to a particle size ≤50μm.

5. The supercapacitor based on a carbon-sequestration building energy storage material according to claim 3, wherein, The electrolyte (4) is a mixed solution of 1.5mol / L NaOH and 0.2mol / L Na2SiO3, and the injection amount is 15-20% of the volume of the electrode member (2).

6. The supercapacitor based on a carbon-sequestration building energy storage material according to claim 1, characterized in that, The polypropylene diaphragm is a plasma-modified non-woven fabric, with a thickness of 0.2mm, a porosity of 40-50%, and a pore diameter of 5-10μm.

7. The supercapacitor based on a carbon sequestration building energy storage material according to claim 2, characterized in that, The current collector plate (1) is a copper-plated aluminum foil, with a surface roughness Ra ≤0.5μm, and a graphene conductive paste layer is coated between the electrode member (2) and the current collector plate (1). The thickness of the graphene conductive paste layer is 10μm, and the conductivity ≥5000S / m. The electrode member (2), the graphene conductive paste layer, and the current collector plate (1) are hot-pressed and connected at 80°C and 10MPa.

8. The supercapacitor based on a carbon sequestration building energy storage material according to claim 1, characterized in that The electrode member (2) has a fractal pore network structure inside, which is composed of interconnected open pores formed by cement hydration and multi-level pores of the carbon-metal framework, and the porosity is 20-30%.

9. A preparation method of a supercapacitor, the supercapacitor according to any one of claims 1-8, characterized in that, The specific steps are as follows: S1. Electrode material preparation: Mix and stir carbon-fixing red mud, carbon-metal framework composite material, cement, sand aggregate and admixture, and mold and cure for 28 days; S2. Electrode-current collector plate (1) assembly: Spray graphene conductive paste on the electrode surface and hot-press and connect it with the copper-plated aluminum foil current collector plate (1); S3. Electrolyte (4) injection and encapsulation: Set a polypropylene diaphragm between the two electrodes, inject the electrolyte (4) and then seal it with epoxy resin.

10. The preparation method of a supercapacitor according to claim 9, characterized in that, In step S1, the curing conditions are an environment of 20°C and 95% humidity, and the vibration compaction process is adopted during molding, with a vibration frequency of 50 Hz, an amplitude of 0.5 mm, and a duration of 30 seconds.

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