Concrete electrode material, preparation method thereof and application of concrete electrode material in supercapacitor

Abstract

The invention provides a concrete electrode material, a preparation method thereof and an application of the concrete electrode material in preparation of a supercapacitor. The preparation method comprises the steps that concrete mortar, paper fibers, nano carbon black and a water reducing agent are evenly mixed to prepare concrete mixed slurry, the mass ratio of the concrete mortar to the paper fibers to the nano carbon black is 1: (0.005-0.01): (0.01-0.02), and the mass ratio of the water reducing agent to the nano carbon black is 0.08-0.1: 1; and pouring the concrete mixed slurry into a mold for shaping and curing. The paper fiber is introduced into the concrete electrode material, so that the capacitance characteristic of a concrete electrode under the condition of low nano carbon black doping amount is enhanced, the mechanical property loss is reduced, and the raw material cost is reduced together with the standard sand. The concrete material is used as an electrode of the supercapacitor, so that the supercapacitor not only has relatively high specific capacitance, but also has relatively high mechanical strength, and is low in cost.

Description

Technical Field

[0001] The present invention relates to the field of supercapacitors, and particularly to a concrete electrode material for energy storage, a preparation method thereof, and an application in the preparation of supercapacitors. Background Art

[0002] With the continuous growth of human demand for fossil energy, environmental problems have become increasingly prominent. Developing a large-scale energy storage device with stable performance, high safety, low environmental pollution, scalability has important practical significance. As a "structure-function integration" energy storage technology, cement-based structural supercapacitors are triggering a paradigm shift in the fields of architecture and energy.

[0003] Chinese Patent Application CN107195478A provides a graphene / magnesium phosphate cement structural supercapacitor and its preparation. Graphene is used as the electrode material, and magnesium phosphate cement is used as the solid electrolyte. Compared with the prior art, the preparation of the solid electrolyte of this capacitor is simple, and the early compressive strength is 5-7.5 MPa. However, this structural supercapacitor has poor working performance of magnesium phosphate cement, and the later strength is difficult to meet the load-bearing requirements of building components. At the same time, due to the high price of graphene electrodes, the volume of the supporting cement-based electrolyte is limited, and it cannot be applied on a large scale.

[0004] Patent Application CN117809988A provides a carbon-high belite cement-based supercapacitor and its preparation method. Carbon black and carbon fiber are added to high belite cement to prepare a carbon cement electrode, and seawater is used as the electrolyte, which is suitable for offshore energy storage; however, its raw material cost is much higher than that of ordinary concrete, and it also cannot be applied on a large scale.

[0005] Therefore, developing a concrete energy storage material with good mechanical properties, excellent energy storage capacity and low cost is crucial for achieving efficient energy storage. Summary of the Invention

[0006] In view of this, the main object of the present invention is to provide a concrete electrode material for energy storage and a preparation method thereof. Paper fibers are introduced into the concrete electrode material, which enhances the capacitance characteristics of the concrete electrode with a low nano-carbon black content, reduces the loss of mechanical properties, and together with standard sand, reduces the raw material cost.

[0007] Another object of the present invention is to provide an application of the above concrete electrode material in the preparation of supercapacitors. The concrete material is used as the electrode of the supercapacitor, so that the supercapacitor not only has a high specific capacitance, but also has high mechanical strength and low cost.

[0008] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a concrete electrode material comprises the following steps: Mixing slurry: uniformly mixing concrete mortar, paper fiber, nano carbon black and water reducing agent to prepare concrete mixed slurry, wherein the mass ratio of the concrete mortar, paper fiber and nano carbon black is 1: (0.005-0.01): (0.01-0.02), and the mass ratio of the water reducing agent to the nano carbon black is 0.08-0.1: 1; Shaping and curing: pour the concrete mixture into a mold for shaping and curing.

[0009] In the concrete electrode material, concrete mortar is mainly used as the matrix material of the electrode. The concrete mortar is mainly obtained by fully stirring and uniformly mixing cement, standard sand and water in a mass ratio of 1:2 to 4:0.5. Among them, the cement is the existing technology, including various types of cement on the market.

[0010] Nano carbon black, as a conductive material, forms a conductive network in the concrete matrix and can absorb charged ions to form a double electric layer to store energy. The particle size of the nano carbon black is preferably 15 to 40 nm, and the specific surface area is greater than 100 m 2 / g.

[0011] Paper fiber mainly opens up the closed pores inside the concrete and guides the nano-carbon black in the pores to connect together to form a conductive carbon network. Its addition builds a connecting bridge for the nano-carbon black in different pores, which can increase the capacitance while minimizing the loss of compressive strength of the concrete substrate. The paper fiber includes various plant fiber raw materials for papermaking or is processed into fiber-shaped finished products by waste paper scraps through processing equipment; wherein the waste paper scraps include cartons, paper rolls, newspapers, book paper and other materials. The paper fiber can be gray paper fiber or turmeric paper fiber. Preferably, the particle size of the paper fiber is 10 to 20 μm.

[0012] The main function of the water reducer is to reduce the amount of water and improve the strength of concrete. Its addition promotes the formation of concrete mixed slurry under low water-cement ratio conditions. If this substance is omitted, it is difficult to form slurry under normal water-cement ratio conditions due to the presence of nano carbon black during stirring. The water reducer is preferably a surface anion active agent such as a polycarboxylate water reducer or a naphthalene water reducer.

[0013] In the shaping and curing step, after the concrete mixed slurry is shaped, it is demolded and cured for 20 to 30 days and then air-dried to obtain the concrete electrode material.

[0014] Therefore, in the concrete electrode material prepared by the above method provided by the present invention, the nano-carbon black spontaneously forms a conductive carbon network during the cement hydration process and is distributed inside the concrete matrix. The process is simple, the cost is low, the structure is stable, the shape can be arbitrarily changed according to the mold, and the overall bearing capacity is strong. In addition, the raw materials for preparing the concrete electrode material are widely sourced and low in cost, having a broad market prospect.

[0015] A concrete electrode material prepared by the above preparation method. The concrete electrode material can be widely used in civil engineering and has broad application prospects.

[0016] A preparation method of a concrete composite electrode, comprising the steps of: Mixing and pulping: uniformly mixing concrete mortar, paper fiber, nano-carbon black and a water reducer to form a concrete mixed slurry, wherein the mass ratio of the concrete mortar, paper fiber and nano-carbon black is 1 : (0.005 - 0.01) : (0.01 - 0.02), and the mass ratio of the water reducer to nano-carbon black is 0.08 - 0.1 : 1; Shaping and curing: pouring the concrete mixed slurry into a mold, and shaping, curing and air-drying together with a current collector to obtain a concrete composite electrode.

[0017] Among them, the step of shaping and curing includes: first pouring the concrete mixed slurry into the mold for shaping, then inserting a current collector into the concrete mixed slurry, and then shaping, demolding and curing for 20 - 30 days. Among them, the main function of the current collector is to collect the current stored on the concrete electrode so as to form a larger current for external output. The current collector can be inserted into the concrete mixed slurry, that is, embedded in the concrete mixed slurry. The material of the current collector is an existing material, such as metal materials such as copper and aluminum, and can also be a carbon fiber mesh structure. Preferably, the current collector is a grid-shaped current collector made of carbon fiber rods, and the diameter of the carbon fiber rods therein is 2 - 3 mm; this avoids problems such as easy rusting and poor durability of metals.

[0018] A concrete composite electrode prepared by the above preparation method. The compressive strength of the concrete composite electrode is 21 - 30 MPa, and the volume specific capacitance at a current density of 100 A / m 3 is 4.5×10 4 ~2.5×10 5 F / m 3 .

[0019] An application of the above concrete electrode material or concrete composite electrode in the preparation of supercapacitors.

[0020] A supercapacitor includes two saturated composite electrodes and a separator disposed between the two saturated composite electrodes. Among them, the saturated composite electrode is prepared by immersing the above-mentioned concrete composite electrode into an electrolyte solution until saturation.

[0021] The function of the separator is to conduct ions, block electrons, and prevent the supercapacitor from short-circuiting. Its material can be polypropylene (PP), polyethylene (PE), a composite material of polypropylene (PP) and polyethylene (PE), etc.

[0022] Furthermore, the supercapacitor further includes a waterproof insulating layer disposed on the outer surface of the entire supercapacitor, and the concrete composite electrode is disposed between the waterproof insulating layer and the separator.

[0023] Therefore, the concrete electrode material prepared by the above technical solution provided by the present invention not only reduces the loss of the mechanical properties of the concrete matrix itself, but also has good energy storage characteristics and capacitance characteristics, and can be widely used in civil engineering structural energy storage based on the principle of supercapacitors. Description of the Drawings

[0024] Figure 1 Schematic structural diagram of the concrete composite electrode provided in Embodiment 1 of the present invention; Figure 2 SEM diagram of the concrete composite electrode provided in Embodiment 1 of the present invention; Figure 3 Schematic structural diagram of the supercapacitor using the concrete composite electrode provided in Embodiment 4 of the present invention; Figure 4 GCD diagram of the constant current charge and discharge curves for the electrochemical performance tests of Examples 4-6 and Comparative Examples 1-4 prepared by the present invention; Figure 5 CV diagram of the cyclic voltammetry curves for the electrochemical performance tests of 1-3 prepared by the present invention and Comparative Examples 1-4; Among the above figures: 1 - waterproof insulating layer, 2 - concrete composite electrode, 3 - separator, 4 - current collector. Detailed Embodiments

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0026] In the ranges disclosed in the present invention, the endpoints and any values of the ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0027] In the present invention, unless otherwise specified and / or described, all numerical values related to the amounts of components are "weight". If not specifically indicated, the terms used in the present invention are common terms in the art. For the preparation processes, test methods, etc. used in each embodiment without special description, they are all conventional means well-known to those skilled in the art, and the raw materials and equipment used can be obtained from public commercial channels.

[0028] In the following examples or comparative examples, the separator uses a commercial supercapacitor separator (NKK TF4030, Japan), the waterproof insulation layer uses commercial waterproof mortar coated with transparent waterproof glue, the paper fiber is turmeric paper fiber (10 - 20 μm, 0.8 g / cm 3 ), the particle size of nano-carbon black is 25 ± 5 nm, and the specific surface area is 420 - 570 m 2 / g.

[0029] Example 1 This example provides a concrete composite electrode for a supercapacitor and its preparation method, including the steps of: Mixing and pulping: Mix 450 g of water, 900 g of 425 magnesium slag portland cement, and 2700 g of standard sand evenly to make concrete mortar, then add 20.25 g of dry paper fiber, 40.5 g of nano-carbon black, and 4 g of polycarboxylate water reducer, and stir well to make a uniformly mixed concrete slurry; Shaping and curing: Pour the concrete slurry into a mold, and insert a grid-shaped current collector 4 made of carbon fiber rods. After shaping, demold and cure for about 28 days, and air dry to obtain the concrete composite electrode as shown in Figure 1 and Figure 2 which can be used as the electrode of a supercapacitor. The composite electrode 2 includes a concrete electrode and a current collector 4, and the current collector 4 is embedded in the concrete electrode.

[0030] Example 2 This example provides a concrete composite electrode for a supercapacitor and its preparation method, including the steps of: Mixing Pulp: Mix 450 g of water, 900 g of 425 magnesium slag Portland cement, and 2700 g of standard sand evenly to make concrete mortar, then add 20.25 g of dry paper fiber, 81 g of nano-carbon black, and 8 g of polycarboxylate water reducer, and stir well to make a uniformly mixed concrete slurry; Shaping and Curing: Pour the concrete slurry into a mold, and insert a grid-shaped current collector made of carbon fiber rods. After shaping, demold and cure for about 28 days, then air dry. The obtained concrete can be used as a composite electrode of a supercapacitor.

[0031] Example 3 This example provides a concrete composite electrode for a supercapacitor and its preparation method, including the steps: Mixing Pulp: Mix 450 g of water, 900 g of 425 magnesium slag Portland cement, and 2700 g of standard sand evenly to make concrete mortar, then add 10.125 g of dry paper fiber, 40.5 g of nano-carbon black, and 4 g of polycarboxylate water reducer, and stir well to make a uniformly mixed concrete slurry; Shaping and Curing: Pour the concrete slurry into a mold, and insert a grid-shaped current collector made of carbon fiber rods. After shaping, demold and cure for about 28 days, then air dry. The obtained concrete can be used as a composite electrode of a supercapacitor.

[0032] Examples 4 - 6 Please refer to Figure 3 , Examples 4 - 6 of the present invention each provide a supercapacitor, including a separator 3, two saturated composite electrodes 2, and two waterproof insulation layers 1 located on the outermost layer. Among them, the separator 3 is located in the middle, and the saturated composite electrodes are arranged between the waterproof insulation layer 1 and the separator 3. The preparation method of this supercapacitor includes: first soak the two concrete composite electrodes 2 in 1 mol / L KCl solution until no bubbles emerge on the surface of the concrete composite electrodes to obtain two saturated composite electrodes, and then package the two concrete composite electrodes 2, separator 3, and waterproof insulation layer 1 according to Figure 3 the structure shown, and the supercapacitor can be obtained. Among them, the concrete composite electrodes in Examples 4 - 6 are the concrete composite electrodes prepared in Examples 1 - 3 respectively.

[0033] Comparative Examples 1 - 5 Comparative Examples 1 - 5 each provide a supercapacitor, whose structure is basically the same as that of the supercapacitor provided in Example 4. The main difference lies in the different formulations of the concrete electrodes in the concrete composite electrodes. The main differences of each comparative example are as follows: Based on Example 1, Comparative Example 1 omits the nano-carbon black therein; On the basis of Example 1, the addition amount of nano-carbon black in Comparative Example 2 is 121.5 g, and the addition amount of polycarboxylate superplasticizer is 12.1 g; On the basis of Example 1, paper fiber is omitted in Comparative Example 3; On the basis of Example 1, the addition amount of paper fiber in Comparative Example 4 is 30.375 g; On the basis of Example 1, polycarboxylate superplasticizer is omitted in Comparative Example 5. However, the raw materials cannot form a slurry and are basically in a powder state; that is, the concrete cannot be formed according to the formula of Comparative Example 5.

[0034] Performance Test 1) Capacitance performance test: A current density of 100 A / m is applied to the supercapacitors provided in Examples 4-6 and Comparative Examples 1-4 for capacitance performance test (instrument and equipment: Princeton VersaSTAT 3F electrochemical workstation), and the test results are as 3 shown in Figure 4 and Figure 5 Table 1; Table 1 Capacitance Performance Test Results Table (unit: F / m 3 ) Sample Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Specific capacitance <![CDATA[5.748×10 4 > <![CDATA[1.962×10 5 > <![CDATA[5.283×10 4 > <![CDATA[2.002×10 -6 > <![CDATA[1.655×10 5 > <![CDATA[1.02×10 3 > <![CDATA[3.51×10 4 > 2) Compressive strength test: The concrete composite electrodes prepared in Examples 1-3 and those used in Comparative Examples 1-4 are subjected to compressive strength test (instrument and equipment: microcomputer-controlled electro-hydraulic servo pressure testing machine HCT206A), and the test results are shown in Table 2 and Figure 4 and Figure 5 .

[0035] Table 2 Compressive Strength Test Results Table (unit: MPa) Sample Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Compressive strength 28.7 22.71 29.46 32.9 12.88 31.1 25.5 The conductive paths formed by nano-carbon black can adsorb charged ions to form an electric double layer to play a energy storage role. The compressive strength of the concrete composite electrode decreases with the increase of the nano-carbon black content, and the capacitance increases with the increase of the nano-carbon black content. The addition of paper fiber builds a connected bridge for the nano-carbon black in different pores, which can improve the capacitance while minimizing the loss of compressive strength.

[0036] Combined with Figures 3 - 4As can be seen from Tables 1-2, Comparative Example 5 shows that the water reducing agent is an essential component for the preparation of concrete electrodes. Without this substance, a concrete slurry cannot be formed under the condition of a low water-cement ratio, and it is thus difficult to prepare the concrete electrode material. Both Example 5 and Comparative Example 2 have relatively high capacitances. However, the compressive strength of Comparative Example 2 is only 12.88 MPa. Compared with the concrete composite electrode used in Comparative Example 3, 0.005 parts of paper fiber were additionally added to the raw materials of the concrete composite electrode prepared in Example 3, resulting in a compressive strength loss of about 5%, but the capacitance increased by about 50 times. When the dosage of paper fiber is less than 0.005 parts by mass, it cannot fully play its role. When the dosage of paper fiber is greater than 0.01 parts by mass, it will have a great impact on the compressive strength. When the dosage of nano-carbon black is less than 0.01 parts by mass, the capacitance value is too small, resulting in waste of the volume of the supercapacitor. When the dosage of nano-carbon black is greater than 0.02 parts by mass, the compressive strength is too low to provide structural bearing capacity. Therefore, upon comprehensive consideration, the content of paper fiber in the raw materials for preparing the concrete material for energy storage provided by the present invention is preferably 0.005-0.01 parts by mass, and the nano-carbon black is 0.01-0.02 parts by mass. With the components cooperating with each other and coordinating, the electrochemical performance and mechanical strength of the concrete electrode can be better balanced, and the raw material cost is low.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features without departing from the spirit of the technical solutions of the present invention, and all of them should be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A preparation method of a concrete electrode material, comprising the steps: Mixed pulping: uniformly mix concrete mortar, paper fiber, nano carbon black and water reducing agent to make a concrete mixed slurry, where The mass ratio of the concrete mortar, paper fiber and nano-carbon black is 1 : (0.005 - 0.01) : (0.01 - 0.02), and the mass ratio of the water reducing agent to nano-carbon black is 0.08 - 0.1 : 1; Shaping and curing: Pour the concrete slurry into a mold for shaping and curing.

2. The preparation method according to claim 1, characterized in that, The concrete mortar is mainly obtained by fully stirring and uniformly mixing cement, standard sand and water in a mass ratio of 1 : 2 - 4 : 0.

5.

3. The preparation method according to claim 1 or 2, characterized in that, In the step of shaping and curing, after the concrete slurry is shaped, it is demolded and cured for 20 - 30 days and then dried to obtain the concrete electrode material.

4. A concrete electrode material prepared by the preparation method according to claim 1 or 2 or 3.

5. A preparation method of a concrete composite electrode, comprising the steps: Mixed pulping: uniformly mix concrete mortar, paper fiber, nano carbon black and water reducing agent to make a concrete mixed slurry, where The mass ratio of the concrete mortar, paper fiber and nano-carbon black is 1 : (0.005 - 0.01) : (0.01 - 0.02), and the mass ratio of the water reducing agent to nano-carbon black is 0.08 - 0.1 : 1; Shaping and curing: Pour the concrete slurry into a mold and shape and cure it together with the current collector, and then dry it to obtain the concrete composite electrode.

6. The preparation method according to claim 5, characterized in that, The step of shaping and curing includes: first pour the concrete slurry into the mold for shaping, then insert the current collector into the concrete slurry, and then shape, demold and cure for 20 - 30 days.

7. A concrete composite electrode prepared by the preparation method according to claim 6.

8. An application of the concrete electrode material according to claim 4 or the concrete composite electrode according to claim 7 in the preparation of a supercapacitor.

9. A supercapacitor, characterized in that, It includes two saturated composite electrodes and a separator disposed between the two saturated composite electrodes. The saturated composite electrode is obtained by soaking the concrete composite electrode according to claim 7 in an electrolyte solution until saturated.

10. The supercapacitor according to claim 9, characterized in that, It further includes a waterproof insulating layer disposed on the outer surface of the entire super-sweet container, and the concrete composite electrode is disposed between the waterproof insulating layer and the separator.

Images