Cement-based electrode material capable of 3D printing, and preparation method and application thereof

Abstract

The invention belongs to the field of electrode materials, and relates to a cement-based electrode material capable of 3D printing and a preparation method and application thereof. The cement-based electrode material comprises 500 to 600 parts of cement, 10 to 25 parts of aluminum sulfate, 70 to 84 parts of surface activated carbon black, 150 to 300 parts of surface modified quartz sand, 7.5 to 15 parts of carbon fiber, 500 to 600 parts of water and 6 to 10 parts of a water reducing agent. The material has excellent mechanical properties and electrical properties, can realize integration of energy storage and structural functions, has high practical application value, and is especially applicable to the fields of intelligent building materials and green energy storage. And through the 3D printing technology, complex structure customization of the cement-based material can be achieved, structural energy storage integration is expected to be achieved, and a new thought is provided for development of a smart energy system in the building field.

Description

Technical Field

[0001] The present invention belongs to the field of electrode materials, and in particular to a 3D printable cement-based material and a preparation method and application thereof. Background Art

[0002] As the imbalance between energy demand and energy production continues to grow, the demand for energy storage is increasing globally. As a material widely used in construction and infrastructure, concrete has excellent structural strength and complete production technology, making it the preferred material for making structurally integrated supercapacitors. Using cement-based electrode materials as a carrier, concrete is designed as a supercapacitor, which can give it energy storage function while maintaining its structural function, bringing new possibilities for buildings and infrastructure. Cement-based electrode materials integrate building materials and energy storage devices by introducing conductive materials and energy storage elements into concrete. This not only reduces the additional space requirements for independent energy storage devices, but also uses the building itself for energy storage and power supply. It is suitable for buildings such as smart houses, off-grid facilities and emergency backup power systems, but this also puts higher requirements on the structural and electrical properties of cement-based electrode materials themselves.

[0003] As a common conductive material, carbon black is widely used in electrode materials due to its good conductivity and low cost. However, the surface of carbon black particles is relatively hydrophobic and its dispersibility in composite materials is poor, resulting in its electrochemical performance in energy storage materials not being fully utilized. Therefore, improving the surface activity of carbon black and enhancing its compatibility with other materials have become one of the key factors in improving the performance of cement-based electrode materials. Quartz sand is a cheap and widely used filler material. Its use can not only reduce the amount of cement in cement-based materials, but also further improve the buildability of 3D printed cement-based materials, but its low conductivity limits its application in cement-based electrode materials. The excellent conductivity and chemical stability of graphene enable it to be used in the modification of quartz sand, thereby effectively improving its conductivity. Based on this, the method of combining graphene-modified quartz sand with surface activated carbon black can better solve the performance bottleneck of carbon black and quartz sand materials in cement-based electrode materials, improve the conductivity, dispersibility and electrochemical properties of the materials, and promote the development and application of high-performance cement-based electrode materials.

[0004] 3D printing technology has a high degree of design freedom and broad application prospects. This technology can easily manufacture complex geometric shapes that cannot be achieved by traditional processes, supports personalized customization, and the material selection covers plastics, metals, ceramics and biomaterials, showing great flexibility. Through 3D printing technology, complex structural customization of cement-based materials can be achieved, providing high specific surface area and optimized ion transmission channels for the design of cement-based electrode materials, thereby improving energy storage performance. The development of a cement-based electrode material with good printability will help realize 3D printing integrated building structure energy storage material supercapacitor technology, which is expected to embed energy storage functions in 3D printed buildings, enabling them to have the ability of self-power supply, energy recovery and management, and promote the intelligent and sustainable development of buildings. Summary of the invention

[0005] The main purpose of the present invention is to provide a 3D printable cement-based electrode material and its preparation method and application, which has certain structural strength and printability and has good electrical properties.

[0006] The technical problem to be solved by the present invention is to achieve uniform dispersion of cement-based building materials and conductive materials during the mixing process.

[0007] Another technical problem to be solved by the present invention is to ensure that the material has both good rheological properties and electrical properties.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A 3D printable cement-based electrode material, comprising the following components in parts by weight:

[0010] 500~600 parts of cement;

[0011] 10-25 parts of aluminum sulfate;

[0012] Surface activated carbon black 70-84 parts;

[0013] 150~300 parts of surface modified quartz sand;

[0014] Carbon fiber 7.5~15 parts;

[0015] 500~720 parts of water;

[0016] 6 to 10 parts of water reducing agent.

[0017] Among them, the surface modified quartz sand is prepared by graphene coating treatment, the surface activated carbon black is prepared by reacting acrylamide and hydrogen peroxide solution, and the volume of the carbon fiber accounts for 0.5~1.0% of the total volume of the cement-based electrode material.

[0018] Furthermore, the cement is ordinary Portland cement having a strength grade greater than or equal to 52.5 according to GB175-2007 general Portland cement standard.

[0019] Furthermore, the carbon black has a specific surface area of ​​>254 m 2 / g, and the carbon fiber is 3mm short chopped carbon fiber.

[0020] Furthermore, the water reducing agent is a polycarboxylic acid-based water reducing agent with a water reducing rate greater than 30% and a solid content of 30-38%.

[0021] Furthermore, the preparation method of the surface activated carbon black includes: dissolving acrylamide and hydrogen peroxide in distilled water to form a reaction solution; adding carbon black, heating to 60-80°C after ultrasonic dispersion, and maintaining for 30-60 minutes; washing the reacted carbon black with deionized water and drying at 60-80°C.

[0022] Furthermore, the preparation method of the surface activated carbon black comprises: adding acrylamide and hydrogen peroxide to distilled water to dissolve them respectively, then adding carbon black, fully mixing and dispersing them by 100-200W ultrasound for 10-20 minutes, heating the mixed system to 60-80°C, maintaining for 30-60 minutes to react, then washing the reacted carbon black with deionized water, and drying in an oven at 60-80°C until the water and solvent are completely removed. The target concentration of acrylamide is 1%-10%, the concentration of hydrogen peroxide solution is 30%, and the mass ratio of hydrogen peroxide, acrylamide and carbon black is (1-3):10:2.

[0023] Furthermore, the preparation method of the surface-modified quartz sand comprises: soaking the quartz sand in a 20-30% v / v hydrochloric acid solution for 2 hours, washing and drying; then adding the dried quartz sand to an ethanol aqueous solution of 60-80% v / v KH-550 silane coupling agent, stirring and heating at high temperature, and drying in an oven at 120-150° C.;

[0024] Furthermore, the preparation method of the surface modified quartz sand includes: soaking the quartz sand in an acid solution, washing it several times and completely drying it in an oven at 120-150°C; adding the acid-washed sand to a mixed solution of ethanol and water containing 60-80% KH-550 silane coupling agent, stirring and heating at 80-120°C for 30-60 minutes, and then drying it in an oven at 120-150°C for 1-2 hours; gradually adding the dried sand to a 2-5 mg / mL graphene oxide solution, stirring it evenly at room temperature, and drying it in an oven at 50-60°C for 24 hours. The acid solution is hydrochloric acid or nitric acid with a concentration of 20-30%, the mass ratio of water to alcohol in the ethanol aqueous solution is 1:(3-4), and the mass ratio of quartz sand, KH-550 silane coupling agent and graphene is 1000:30:(1-2).

[0025] The present invention also provides a method for preparing the above-mentioned 3D printable cement-based electrode material, comprising the following steps:

[0026] 1) Weigh cement, aluminum sulfate, surface-modified quartz sand, surface-activated carbon black, and carbon fiber in proportion and mix them evenly to obtain a dry material;

[0027] 2) mixing water and a water reducing agent in proportion to obtain a liquid mixed solution;

[0028] 3) Add the mixed solution to the dry material in batches and stir evenly in multiple times;

[0029] 4) The mixed slurry is formed into an electrode material by 3D printing or molding.

[0030] Furthermore, the method for preparing the 3D printable cement-based electrode material comprises the following steps:

[0031] Step 1, weigh cement, aluminum sulfate, surface activated carbon black, surface modified quartz sand, and carbon fiber according to proportion, stir for 2 minutes to fully mix the components, and obtain a uniformly mixed dry material;

[0032] Step 2, weighing water and water reducing agent in proportion, and stirring to obtain a mixed solution;

[0033] Step 3: Pour 60% of the mixed solution into the evenly mixed dry material and start stirring at the same time; after stirring for 1 minute, add 20% of the mixed solution and continue stirring for 1 minute; finally, add the remaining 20% ​​of the mixed solution and continue stirring for 3 minutes.

[0034] Step 4: The mixed material after stirring is molded or 3D printed to form a cement-based electrode material.

[0035] The present invention also provides the use of the above-mentioned 3D printable cement-based electrode material in the preparation of capacitors.

[0036] Furthermore, the cement-based electrode material according to claim 1 is cut into thin sheets with a thickness of 2 to 5 mm, and the sheets are arranged in the order of carbon paper, cement-based electrode material, electrolyte solution, glass fiber separator, electrolyte solution, cement-based electrode material, and carbon paper to be assembled into a capacitor.

[0037] Carbon black itself is highly hydrophobic, and there may be problems with dispersion and mixing. Through the solution prepared with acrylamide and hydrogen peroxide, a free radical reaction is used to initiate a copolymerization reaction between acrylamide and the carbon black surface to form a hydrophilic polymer chain and modify its surface; the 3D printing material of the electrode material needs to be printed continuously at a high height, and there are certain requirements for the material structure development rate. Aluminum sulfate is used to promote the early hydration process; in order to increase the overall yield stress of the 3D printing material and reduce the amount of cement itself, fine quartz sand is required, but quartz sand itself is not conductive, and the overall conductivity will be reduced in the material, so it is modified by graphene coating. The modified material has good rheological properties after mixing, which is convenient for 3D printing, and has good mechanical and electrical properties after the material hardens.

[0038] Beneficial Effects

[0039] The present invention effectively improves the dispersion performance of carbon black in cement-based materials or other matrices by performing surface activation treatment on carbon black. This surface activation method generates hydrophilic polymer chains on the surface of carbon black, thereby enhancing the dispersion ability between carbon black and other materials. During the mixing process, the activated carbon black can not only avoid agglomeration, but also be evenly distributed inside the material. Compared with unactivated carbon black, the activated carbon black particles can be better integrated into the matrix material to form a uniform composite system. Excellent dispersibility helps to improve the overall performance of the material, especially the balance between energy storage performance and mechanical properties. This uniform dispersion also reduces the generation of local defects, thereby improving the stability and durability of the composite material.

[0040] The present invention modifies quartz sand with graphene, and evenly attaches or embeds highly conductive graphene materials on the surface of quartz sand particles, so that the quartz sand particles have good conductive properties. This modified quartz sand not only retains the role of quartz sand as an aggregate to provide mechanical support in cement-based materials, which can effectively improve the buildability of the material, but also forms an efficient conductive network in the material, thereby significantly improving the overall conductivity. Conventional cement-based electrode materials usually rely on doping with conductive fillers (such as carbon black and graphite) to improve conductivity, but the distribution of conductive materials is often uneven, resulting in limited conductivity and the introduction of more material defects. The present invention modifies quartz sand with graphene, which improves the buildability of the material while achieving simultaneous optimization of the conductive properties of the material, providing a new method for improving the performance of cement-based materials in energy storage applications.

[0041] The addition of aluminum sulfate promotes early hydration, enabling it to meet the requirements of early strength development in 3D printing. The material has excellent mechanical and electrical properties, can realize the integration of energy storage and structural functions, and has high practical application value, especially in the field of smart building materials and green energy storage. Through 3D printing technology, complex structural customization of cement-based materials can be achieved, and it is expected to realize structural energy storage integration, providing new ideas for the development of smart energy systems in the construction field.

[0042] The 3D printable cement-based electrode material of the present invention has good rheological properties, can be used for large-scale 3D printing of energy storage materials, and has high practicality. 3D printing technology can accurately construct complex geometric structures through layer-by-layer manufacturing, providing higher design freedom for the preparation of electrode materials. Applying this technology to the preparation of cement-based materials and electrode composites can optimize material distribution and concentrate energy storage materials in specific areas, such as the surface or internal electrode layer, to improve energy storage efficiency. Enhance structural performance, achieve a balance between mechanical properties and electrochemical properties through topological optimization design, take into account both strength and functionality, can withstand loads, and can adapt to diverse engineering needs with complex shapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of a supercapacitor assembled from 3D printable cement-based electrode materials;

[0044] Figure 2 is a cyclic voltammogram of a supercapacitor assembled from the electrode material in Example 2;

[0045] Figure 3 1 is a cyclic voltammogram of a supercapacitor assembled with the electrode material of Example 3 having an electrode thickness of 2 mm;

[0046] Figure 4 This is the cyclic voltammogram of the supercapacitor assembled with the electrode material of Example 4 with a water-to-gel ratio of 1.0. DETAILED DESCRIPTION

[0047] The following is a further detailed description of the present invention:

[0048] Example 1

[0049] A 3D printable cement-based electrode material comprises the following components, measured by weight: 600 parts of cement, 25 parts of aluminum sulfate, 84 parts of surface-activated carbon black, 300 parts of surface-modified quartz sand, 15 parts of carbon fiber, 615 parts of water, and 10 parts of a water reducing agent.

[0050] The cement is silicate cement that meets the general silicate cement standard GB175-2007 and has a strength grade greater than or equal to 52.5.

[0051] The preparation method of the surface activated carbon black comprises: dissolving acrylamide and hydrogen peroxide in distilled water to form a reaction solution; adding carbon black, and heating to 70° C. after ultrasonic dispersion, and maintaining for 60 minutes; washing the reacted carbon black with deionized water, and drying at 70° C.

[0052] The preparation method of the surface modified quartz sand comprises: soaking the quartz sand in a 20% v / v hydrochloric acid solution for 2 hours, washing and drying at 120° C.; adding the dried quartz sand to an ethanol aqueous solution of 80% v / v KH-550 silane coupling agent, stirring and heating at 80° C. for 60 minutes, and then drying in an oven at 120° C. for 2 hours; adding the dried quartz sand to a 2 mg / mL graphene oxide solution, stirring at room temperature, and then drying in an oven at 60° C. for 24 hours.

[0053] The water reducing agent is a polycarboxylic acid-based water reducing agent, the water reducing rate of which is greater than 30%, and the solid content is 30% to 38%.

[0054] Among them, the water-to-cement ratio of the electrode material is 0.8; the volume of carbon fiber accounts for 1.0% of the total volume of the cement-based electrode material; the concentration of acrylamide used in the preparation of surface-activated carbon black is 5%, the concentration of hydrogen peroxide solution is 30%, and the mass ratio of hydrogen peroxide, acrylamide and carbon black is 1:10:2; in the preparation of surface-modified quartz sand, the mass ratio of quartz sand, KH-550 silane coupling agent and graphene oxide used is 1000:30:1.

[0055] The preparation method and performance test of the above-mentioned 3D printable cement-based electrode material include the following steps:

[0056] Step 1, stirring process: (1) Weigh various dry materials in proportion and stir for 2 minutes to obtain a mixed dry material; the dry material includes cement, aluminum sulfate, surface-activated carbon black, surface-modified quartz sand and carbon fiber; (2) Mix a water reducer with water according to corresponding weight parts to obtain a mixed solution; (3) Add 60% of the mixed solution to the mixed dry material and stir for 1 minute to obtain a mixture; (4) Add the remaining 40% of the mixed solution to the mixture and stir for 1 minute; finally, add the remaining 20% ​​of the mixed solution and continue stirring for 3 minutes to obtain a cement-based electrode material that can be 3D printed;

[0057] Step 2: Printability test: Perform printability test on the stirred material, including static yield stress, plastic viscosity, thixotropy, slump, and fluidity;

[0058] Step 3, molding process: Pour the mixed material after stirring into a 40mm×40mm×40mm cube plastic mold, fully vibrate it and then coat the surface for curing; during the 3D printing process, the material must have good rheological properties, including initial static yield stress and appropriate thixotropy, to ensure molding quality.

[0059] Step 4: Mechanical properties test: When the curing age reaches 28 days, take out the hardened cement-based electrode material sample and conduct a mechanical properties test.

[0060] Example 2

[0061] A supercapacitor based on a 3D printable cement-based electrode material comprises the following components, measured by weight: 600 parts of cement, 25 parts of aluminum sulfate, 84 parts of surface-activated carbon black, 300 parts of surface-modified quartz sand, 15 parts of carbon fiber, 615 parts of water, and 10 parts of a water reducing agent.

[0062] Among them, the water-to-binder ratio of the electrode material, the volume percentage of carbon fiber, the preparation of surface activated carbon black and surface modified quartz sand are the same as those in Example 1.

[0063] The stirring process and printability test of the 3D printable cement-based electrode material in the above embodiment are the same as those in Example 1. The molding process is different from that in Example 1 in that a 50mm×50mm×50mm cubic silicone mold is used for molding, and the surface is coated and cured after sufficient vibration; after the curing age reaches 28 days, a precision cutting machine is used to cut it into 5mm thick sheets as electrode materials.

[0064] After the electrode materials are prepared, Figure 1 The structure shown is used to assemble a supercapacitor, including carbon paper 1, electrode material 2, electrolyte solution 3 and glass fiber separator 4, and then an electrical performance test is performed. Before the test, the electrode material is soaked in the electrolyte solution until it is saturated with water.

[0065] The electrolyte solution is 1 mol / L ammonium acetate solution, and the size of the glass fiber separator is 100 mm × 100 mm × (0.29 ± 0.01) mm.

[0066] The electrical performance tests of Example 2 included cyclic voltammetry (CV) and cross-current charge-discharge (DC) tests. The capacitor capacity was calculated based on constant current charge-discharge. The electrical performance test was powered by a 1V power supply at 0.5 mA / cm 2 The current density is constant current charge and discharge, the output voltage is 0.70V, and the capacitor capacity is measured to be 186.3mF / cm 2 .

[0067] Example 3

[0068] A supercapacitor based on a 3D printable cement-based electrode material comprises the following components, measured by weight: 600 parts of cement, 25 parts of aluminum sulfate, 84 parts of surface-activated carbon black, 300 parts of surface-modified quartz sand, 15 parts of carbon fiber, 615 parts of water, and 10 parts of a water reducing agent.

[0069] Among them, the water-to-binder ratio of the electrode material, the volume percentage of carbon fiber, the preparation of surface activated carbon black and surface modified quartz sand are the same as those in Example 1.

[0070] The stirring process and printability test of the 3D printable cement-based electrode material in the above embodiment are the same as those in Example 1. The molding process is different from that in Example 1 in that a 50mm×50mm×50mm cubic silicone mold is used for molding, and the surface is coated and cured after sufficient vibration; after the curing age reaches 28 days, a precision cutting machine is used to cut it into 2mm thick slices.

[0071] After the electrode materials are prepared, Figure 1 The structure shown is assembled into a supercapacitor.

[0072] The electrical performance test of Example 3 includes cyclic voltammetry test and cross-current charge-discharge test. Before the test, the electrode material is soaked in electrolyte solution until saturated with water, and the capacitor capacity is calculated based on constant current charge-discharge. The electrical performance test uses a 1V power supply at 0.5mA / cm 2 The current density is constant current charge and discharge, the output voltage is 0.87V, and the capacitor capacity is 77.6mF / cm 2 .

[0073] Example 4

[0074] A supercapacitor based on a 3D printable cement-based electrode material comprises the following components, measured by weight: 600 parts of cement, 25 parts of aluminum sulfate, 84 parts of surface-activated carbon black, 300 parts of surface-modified quartz sand, 15 parts of carbon fiber, 700 parts of water, and 10 parts of a water reducing agent.

[0075] The volume ratio of carbon fiber, surface activated carbon black and surface modified quartz sand of the electrode material are the same as those in Example 1. The difference from Example 1 is that the water-to-binder ratio of the electrode material is 1.0.

[0076] The preparation process, printability and mechanical property testing process of the 3D printable cement-based electrode material in the above embodiment are the same as those in Example 1. The molding process is different from that in Example 1 in that a 50mm×50mm×50mm cubic silicone mold is used for molding, and the surface is fully vibrated and coated for curing; after the curing age reaches 28 days, a precision cutting machine is used to cut it into 5mm thick sheets.

[0077] After the electrode materials are prepared, Figure 1 The structure shown is assembled into a supercapacitor.

[0078] The electrical performance test of Example 4 includes cyclic voltammetry test and cross-current charge-discharge test. Before the test, the electrode material is soaked in electrolyte solution until saturated with water, and the capacitor capacity is calculated based on constant current charge-discharge. The electrical performance test uses a 1V power supply at 0.5mA / cm 2 The current density is constant current charge and discharge, the output voltage is 0.86V, and the capacitor capacity is measured to be 96.5mF / cm 2 .

[0079] Comparative Example 1

[0080] On the basis of Example 1, the difference from Example 1 is that 7.5 parts of carbon fiber are used, and the volume of carbon fiber accounts for 0.5% of the total volume of the cement-based electrode material.

[0081] Comparative Example 2

[0082] Based on Example 1, the difference from Example 1 is that carbon fiber is not used.

[0083] Comparative Example 3

[0084] Based on Example 1, different from Example 1, aluminum sulfate is not used.

[0085] Comparative Example 4

[0086] Based on Example 2, different from Example 2, carbon fiber is not used.

[0087] The electrical performance test of Comparative Example 4 includes cyclic voltammetry test and cross-current charge-discharge test. Before the test, the electrode material is soaked in electrolyte solution until saturated with water, and the capacitor capacity is calculated based on constant current charge-discharge. The electrical performance test uses a 1V power supply at 0.5mA / cm 2 The current density is constant current charge and discharge, the output voltage is 0.68V, and the capacitor capacity is 58.8mF / cm 2 .

[0088] Since comparative example 4 does not use carbon fiber compared to example 2, the capacitor capacity of comparative example 4 is lower than that of example 2. This is because the addition of carbon fiber can improve the electrical properties of the material, indicating that the supercapacitor assembled with cement-based electrode materials with a carbon fiber volume ratio of 1.0% has better energy storage performance.

[0089] Comparative Example 5

[0090] Based on Example 2, unlike Example 2, unmodified carbon black is used. Since Comparative Example 5 does not use modified carbon black compared to Example 2, the electrode material of Comparative Example 5 cannot be evenly dispersed during the stirring process. Since the unmodified carbon black has poor compatibility with other materials, the carbon black floats on the surface of the liquid during the preparation of the electrode material, and the other solid components agglomerate, and the materials cannot be mixed into a uniform slurry, and thus cannot be formed. However, the electrode material in Example 2 uses modified carbon black, so the various component materials can be well mixed during the stirring process.

[0091] Comparative Example 6

[0092] Based on Example 2, the difference from Example 2 is that unmodified quartz sand is used.

[0093] The electrical performance test of Comparative Example 6 includes cyclic voltammetry test and cross-current charge-discharge test. Before the test, the electrode material is soaked in electrolyte solution until saturated with water, and the capacitor capacity is calculated based on constant current charge-discharge. The electrical performance test uses a 1V power supply at 0.5mA / cm 2 The current density is constant current charge and discharge, the output voltage is 0.65V, and the capacitor capacity is measured to be 47.2mF / cm 2 .

[0094] Since comparative example 6 uses unmodified quartz sand compared to example 2, the capacitor capacity of comparative example 6 is lower than that of example 2. This is because the modified quartz sand improves the electrical properties of the material, indicating that the supercapacitor assembled with cement-based electrode materials prepared with modified quartz sand has better energy storage performance.

[0095] The printability of the electrode materials in the above embodiments and control examples is judged according to the working performance and rheological properties of the freshly mixed electrode material slurry. Among them, the working performance is tested according to GB / T 2419-2005, and the cylinder used in the slump test is 80 mm high and 80 mm in inner diameter. The equipment used for the rheological property test is the RST-SST rotational rheometer. The test uses a paddle rotor with a blade size of 10 mm × 20 mm. The static shear program is to shear the fresh slurry at a shear rate of 0.1 r / s for 180 s at a low speed, and the dynamic shear program is to uniformly accelerate from a shear rate of 0 to 50 r / s for 90 s, and then uniformly reduce the speed from 50 r / s to a shear rate of 0 for 90 s. The mechanical property test of the electrode material refers to the compressive strength test method of GB / T 17671-2021 cement mortar strength test method.

[0096] During the above performance test process, the test conditions were maintained at a temperature of (25±2)°C and a relative humidity of (70±3)%.

[0097] The printability and mechanical properties test results of the 3D printable cement-based electrode material in the present invention are shown in Table 1.

[0098] Table 1 Comparison results of printability and mechanical properties

[0099]

[0100] As can be seen from Table 1, Examples 1 and 4 have good fresh workability and rheological properties, the slump loss of which is less than 10 mm, with good buildability, fluidity in the range of 160-210 mm, initial static yield stress in the range of 1500-3000 Pa, and the material can be smoothly extruded from the print head. By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that the addition of carbon fiber not only provides electrical conductivity for cement-based electrode materials, but also improves the mechanical properties of the material to a certain extent, and does not have a significant effect on the rheological properties, so it will not affect the 3D printing process of the electrode material. Compared with Example 1, the compressive strength of Comparative Example 3 is reduced by 56.1%, which shows that the addition of aluminum sulfate contributes to the development of early strength of cement-based electrode materials.

[0101] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A 3D printable cement-based electrode material, characterized in that: The composition includes the following components in parts by weight: 500~600 parts of cement; 10-25 parts of aluminum sulfate; Surface activated carbon black 70-84 parts; 150~300 parts of surface modified quartz sand; Carbon fiber 7.5~15 parts; 500~720 parts of water; Water reducing agent 6-10 parts; Among them, surface modified quartz sand is prepared by graphene coating treatment, surface activated carbon black is prepared by the reaction of acrylamide and hydrogen peroxide solution, and the volume of carbon fiber accounts for 0.5~1.0% of the total volume of the material.

2. The 3D printable cement-based electrode material according to claim 1, characterized in that: The cement is silicate cement that meets the general silicate cement standard GB175-2007 and has a strength grade greater than or equal to 52.

5.

3. The 3D printable cement-based electrode material according to claim 1, characterized in that: The preparation method of the surface activated carbon black comprises: dissolving acrylamide and hydrogen peroxide in distilled water to form a reaction solution; Add carbon black, disperse by ultrasonic, and heat to 60-80°C for 30-60 minutes; The carbon black after the reaction was washed with deionized water and dried at 60-80°C.

4. The 3D printable cement-based electrode material according to claim 3, characterized in that: The mass ratio of hydrogen peroxide, acrylamide and carbon black is 1~3:10:

2.

5. The 3D printable cement-based electrode material according to claim 1, characterized in that: The preparation method of the surface modified quartz sand comprises: Soak the quartz sand in 20-30% v / v hydrochloric acid solution for 2 hours, clean and dry; Then add the dry quartz sand to 60~80% v / v KH-550 silane coupling agent in ethanol water solution, stir and heat at high temperature, and then dry in an oven at 120~150℃; The dried quartz sand is added into the graphene oxide solution, stirred and then dried.

6. The 3D printable cement-based electrode material according to claim 5, characterized in that: The mass ratio of quartz sand, KH-550 silane coupling agent and graphene oxide is 1000:30:1~2.

7. The 3D printable cement-based electrode material according to claim 1, characterized in that: The water reducing agent is a polycarboxylic acid-based water reducing agent, the water reducing rate of which is greater than 30%, and the solid content is 30% to 38%.

8. The method for preparing a 3D printable cement-based electrode material according to claim 1, characterized in that: The following steps are involved: Weigh cement, aluminum sulfate, surface-modified quartz sand, surface-activated carbon black, and carbon fiber according to proportion and mix them evenly to obtain a dry material; Mixing water and a water reducing agent in proportion to obtain a liquid mixed solution; Add the mixed solution to the dry material in batches and stir evenly several times; The mixed slurry is formed into electrode material through 3D printing or mold forming.

9. Use of the 3D printable cement-based electrode material according to claim 1 in preparing a capacitor.

10. The use according to claim 9, characterized in that: The cement-based electrode material according to claim 1 is cut into thin sheets of 2 to 5 mm thickness, and the sheets are arranged in the order of carbon paper, cement-based electrode material, electrolyte solution, glass fiber separator, electrolyte solution, cement-based electrode material, and carbon paper to be assembled into a capacitor.

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