A porous structure cement solid-state electrolyte and a preparation method and application thereof

Abstract

The present application relates to a kind of porous structure cement solid electrolyte and its preparation method and application.Using chemical foaming method, with potassium iodide as exciter, hydrogen peroxide as foaming agent, three-dimensional porous structure cement solid electrolyte is synthesized, effective regulation of pore structure is realized, the ionic conductivity of electrolyte is improved, and interface contact is improved.Porous cement solid electrolyte is subsequently assembled into symmetric cement structure supercapacitor with reduced graphene oxide composite material, and the area specific capacitance is 351.5 mF / cm 2 When current density is 0.5 mA / cm 2 2. Power density is 110.6 W / kg, and energy density is 21.6 Wh / kg. When power density increases to 1106.2 W / kg, energy density can still be maintained at 13.8 Wh / kg. After 5000 times of constant current charge-discharge at current density of 10 mA / cm 2 , the area specific capacitance retention rate is as high as 93.8%.

Description

Technical Field

[0001] This invention relates to the field of structural energy storage technology, and in particular to a porous cement solid electrolyte, its preparation method, and its application. Background Technology

[0002] Structural supercapacitors are highly efficient energy storage devices that have attracted much attention in the field of electrochemical energy storage due to their advantages such as high power density (10-20 times that of batteries), short charging time, long cycle life (20-30 times that of batteries), environmental friendliness, and mechanical strength. Among these advantages, the solid electrolyte in structural supercapacitors possesses certain structural strength, energy storage performance, and membrane functionality.

[0003] Currently, existing technologies disclose the use of cement to prepare solid electrolytes because cement has a certain number of pores that can be used for ion storage and transport. Furthermore, cement possesses a certain strength and is inexpensive, making it a solid electrolyte that simultaneously provides structural support and energy storage. However, while cement solid electrolytes possess these advantages, their low porosity and poor interfacial contact between the electrode material and the electrolyte result in a low ion storage capacity within the electrolyte, a slow ion diffusion rate, and a small number of ions adsorbed on the electrode surface. Ultimately, this prevents the assembled cement-structured supercapacitor from fully realizing its electrochemical performance.

[0004] Therefore, there is an urgent need in this field to develop a porous cement solid electrolyte, optimize and regulate the pore structure inside the electrolyte, expand the ion storage capacity, and accelerate the ion transport rate, so as to solve the problems of low ionic conductivity and poor interfacial contact of cement solid electrolyte in cement structure capacitors. Summary of the Invention

[0005] The purpose of this invention is to provide a porous cement solid electrolyte, its preparation method, and its application. This invention employs a chemical foaming method to create pores within the cement, using potassium iodide as an activator and hydrogen peroxide as a foaming agent to synthesize a three-dimensional porous cement solid electrolyte. This achieves effective control over the pore structure, improves the electrolyte's ionic conductivity, and enhances interfacial contact.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] The first objective of this invention is to provide a method for preparing a porous cement solid electrolyte, the specific steps of which are as follows:

[0008] S1. Dissolve potassium iodide and foam stabilizer in water and stir until homogeneous to obtain a mixed system;

[0009] S2. Add the mixture obtained in step S1 to the cement and stir evenly to obtain cement paste;

[0010] S3. Add foaming agent to the cement slurry obtained in step S2 and stir evenly to obtain cement slurry.

[0011] S4. After pouring and curing the cement slurry obtained in step S3, a porous cement solid electrolyte is obtained.

[0012] Furthermore, in step S1, the foam stabilizer is calcium stearate, and the water is deionized water.

[0013] Furthermore, in step S1, the stirring method is magnetic stirring, and the stirring time is 8s to 12s, preferably 10s.

[0014] Furthermore, in step S2, the cement is silicate cement.

[0015] Furthermore, in step S2, the stirring time is 1 min to 3 min, preferably 2 min.

[0016] Furthermore, in step S3, the foaming agent is hydrogen peroxide.

[0017] Furthermore, in step S3, the stirring time is 20s to 40s, preferably 30s.

[0018] Further, in steps S1 to S3, the mass ratio of potassium iodide, foam stabilizer, water, cement, and foaming agent is 0.8:0.1 to 0.5:40:100:5.

[0019] Furthermore, the mass ratio of potassium iodide, foam stabilizer, water, cement, and foaming agent is 0.8:0.4:40:100:5.

[0020] The second objective of this invention is to provide a porous cement solid electrolyte, which is prepared by the above-described preparation method.

[0021] Furthermore, the porous cement solid electrolyte exhibits a porous structure with irregular pore channels.

[0022] Furthermore, the pore volume ranges from 0.25 to 0.35 mL / g, the porosity ranges from 21.7% to 41.1%, the average pore size ranges from 64 to 100 nm, and the dry density of the porous cement solid electrolyte ranges from 280 to 750 kg / m³. 3 .

[0023] The third objective of this invention is to provide an application of a porous cement solid electrolyte, which is used to prepare cement-structured supercapacitors.

[0024] Furthermore, the cement structure supercapacitor includes a metal layer, a reduced graphene oxide layer, and a porous cement solid electrolyte. One side of each of the two reduced graphene oxide layers is connected to the upper and lower sides of the porous cement solid electrolyte, respectively, and the other side of each of the two reduced graphene oxide layers is provided with a metal layer.

[0025] Furthermore, the method for preparing the cement structure supercapacitor is as follows:

[0026] S1. Graphene oxide slurry is uniformly coated onto a metal, reacted at high temperature, and then washed and dried to obtain a reduced graphene oxide composite material.

[0027] S2. Dissolve potassium iodide and foam stabilizer in water, add to cement, add foaming agent, and stir evenly to obtain cement slurry;

[0028] S3. The cement slurry obtained in step S2 is poured between two pieces of reduced graphene oxide composite material, and after curing, a cement structure supercapacitor is obtained.

[0029] Furthermore, in step S1, the metal is nickel foam.

[0030] Furthermore, in step S3, the maintenance period is 20 to 30 days.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) This invention successfully synthesized a porous cement solid electrolyte using chemical foaming, which improves the ionic conductivity of the material. Electrochemical tests show that the ionic conductivity of the porous cement solid electrolyte is 20.5 mS / cm. Potassium iodide plays a dual role: first, as an activator, it increases the porosity of the porous cement solid electrolyte, thereby improving the overall ionic conductivity; second, as a redox active material, it additionally provides pseudocapacitance for the cement structure supercapacitor, improving the electrochemical performance of the capacitor.

[0033] (2) A cement-structured supercapacitor assembled from porous cement solid electrolyte and reduced graphene oxide composite material operates at a current density of 0.5 mA / cm². 2 The area capacitance at that time was 351.5 mF / cm². 2 At a power density of 110.6 W / kg, the energy density is 21.6 Wh / kg. When the power density increases to 1106.2 W / kg, the energy density remains at 13.8 Wh / kg. At 10 mA / cm²... 2 After 5000 constant current charge-discharge cycles at a current density, its area specific capacitance retention rate is as high as 93.8%, demonstrating excellent electrochemical performance.

[0034] (3) The porous cement solid electrolyte of the present invention is mainly prepared from hydrogen peroxide, potassium iodide and silicate cement, and assembled with reduced graphene oxide composite material to form a cement structure supercapacitor. The process is simple, easy to operate, and can achieve large-scale production. Attached Figure Description

[0035] Figure 1 This is a schematic diagram illustrating the fabrication of the porous cement solid electrolyte and the cement structure supercapacitor in this invention.

[0036] Figure 2 The images are SEM images of the porous cement solid electrolytes in Examples 1-5 and Comparative Example 1 of this invention.

[0037] Figure 3 The following are the (a) pore volume differential distribution curves, (b) pore volume cumulative distribution curves, (c) porosity, (d) compressive strength, (e) ionic conductivity, and (f) multifunctional diagrams of the porous cement solid electrolytes in Examples 1-5 and Comparative Example 1 of this invention.

[0038] Figure 4 The electrochemical performance of symmetrical cement-structured supercapacitors assembled using reduced graphene oxide composite materials as positive and negative electrodes, in conjunction with porous cement solid electrolytes from Examples 1-5 and Comparative Example 1, was characterized as follows: (a) Cyclic voltammetry curves at a scan rate of 10 mV / s; (b) Cyclic voltammetry curves at different scan rates (10-200 mV / s); (c) Cyclic voltammetry curves at 0.5 mA / cm². 2 (d) Constant current charge-discharge curves at different current densities (0.5-10 mA / cm²). 2 (e) Constant current charge-discharge curves at different current densities (0.5-10 mA / cm²); (f) Impedance plots; (g) Bode plots; 2 (h) Area-to-capacitance ratio; (i) Lagun plot; (h) Cyclic performance.

[0039] The following are the symbols in the attached diagram: 1. Metal layer, 2. Reduced graphene oxide layer, 3. Porous cement solid electrolyte. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0041] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other. Unless otherwise specified, the reagents, methods, instruments, and equipment used in the present invention are conventional reagents, methods, instruments, and equipment in the art. Unless otherwise specified, the reagents and materials used in the following embodiments are commercially available and of analytical grade.

[0042] Example 1

[0043] This embodiment provides a method for preparing porous cement solid electrolyte, the specific steps of which are as follows:

[0044] (1) Dissolve 0.8g calcium stearate and 0.1g potassium iodide in 40g deionized water and mix the above solution evenly with magnetic stirring to obtain a mixed system.

[0045] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0046] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0047] (4) Quickly pour the cement slurry obtained in step (3) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the process of preparing the cement slurry in step (3). The cement slurry prepared in step (3) was then poured into a cubic compressive strength test mold (64cm). 3 The compressive strength of the test sample is obtained in the process.

[0048] Furthermore, this embodiment also provides a method for preparing a cement-structured supercapacitor, the specific steps of which are as follows:

[0049] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0050] (2) Dissolve 0.8g calcium stearate and 0.1g potassium iodide in 40g deionized water, add to 100g silicate cement, add 5g hydrogen peroxide, and stir evenly to obtain cement slurry.

[0051] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0052] Example 2

[0053] This embodiment provides a method for preparing porous cement solid electrolyte, the specific steps of which are as follows:

[0054] (1) Dissolve 0.8g calcium stearate and 0.2g potassium iodide in 40g deionized water and mix the above solution evenly by magnetic stirring to obtain a mixed system.

[0055] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0056] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0057] (4) Quickly pour the cement slurry obtained in step (3) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the process of preparing the cement slurry in step (3). The cement slurry prepared in step (3) was then poured into a cubic compressive strength test mold (64cm). 3 The test sample for compressive strength was obtained in the process.

[0058] Furthermore, this embodiment also provides a method for preparing a cement-structured supercapacitor, the specific steps of which are as follows:

[0059] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0060] (2) Dissolve 0.8g calcium stearate and 0.2g potassium iodide in 40g deionized water, add to 100g silicate cement, add 5g hydrogen peroxide, and stir evenly to obtain cement slurry.

[0061] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3 To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0062] Example 3

[0063] This embodiment provides a method for preparing porous cement solid electrolyte, the specific steps of which are as follows:

[0064] (1) Dissolve 0.8g calcium stearate and 0.3g potassium iodide in 40g deionized water and mix the above solution evenly by magnetic stirring to obtain a mixed system.

[0065] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0066] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0067] (4) Quickly pour the cement slurry obtained in step (3) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the process of preparing the cement slurry in step (3). The cement slurry prepared in step (3) was then poured into a cubic compressive strength test mold (64cm). 3 The test sample for compressive strength was obtained in the process.

[0068] Furthermore, this embodiment also provides a method for preparing a cement-structured supercapacitor, the specific steps of which are as follows:

[0069] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0070] (2) Dissolve 0.8g calcium stearate and 0.3g potassium iodide in 40g deionized water, add to 100g silicate cement, add 5g hydrogen peroxide, and stir evenly to obtain cement slurry.

[0071] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3 To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0072] Example 4

[0073] This embodiment provides a method for preparing porous cement solid electrolyte, the specific steps of which are as follows:

[0074] (1) Dissolve 0.8g calcium stearate and 0.4g potassium iodide in 40g deionized water and mix the above solution evenly by magnetic stirring to obtain a mixed system.

[0075] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0076] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0077] (4) Quickly pour the cement slurry obtained in step (3) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the process of preparing the cement slurry in step (3). The cement slurry prepared in step (3) was then poured into a cubic compressive strength test mold (64cm). 3 The test sample for compressive strength was obtained in the process.

[0078] Furthermore, this embodiment also provides a method for preparing a cement-structured supercapacitor, the specific steps of which are as follows:

[0079] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0080] (2) Dissolve 0.8g calcium stearate and 0.4g potassium iodide in 40g deionized water, add to 100g silicate cement, add 5g hydrogen peroxide, and stir evenly to obtain cement slurry.

[0081] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3 To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0082] Example 5

[0083] This embodiment provides a method for preparing porous cement solid electrolyte, the specific steps of which are as follows:

[0084] (1) Dissolve 0.8g calcium stearate and 0.5g potassium iodide in 40g deionized water and mix the above solution evenly by magnetic stirring to obtain a mixed system.

[0085] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0086] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0087] (4) Quickly pour the cement slurry obtained in step (3) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the process of preparing the cement slurry in step (3). The cement slurry prepared in step (3) was then poured into a cubic compressive strength test mold (64cm). 3 The test sample for compressive strength was obtained in the process.

[0088] Furthermore, this embodiment also provides a method for preparing a cement-structured supercapacitor, the specific steps of which are as follows:

[0089] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0090] (2) Dissolve 0.8g calcium stearate and 0.5g potassium iodide in 40g deionized water, add to 100g silicate cement, add 5g hydrogen peroxide, and stir evenly to obtain cement slurry.

[0091] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3 To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0092] Comparative Example 1

[0093] This comparative example provides a method for preparing cement solid electrolyte, the specific steps of which are as follows:

[0094] (1) Dissolve 0.8g of calcium stearate in 40g of deionized water and mix the solution evenly using magnetic stirring to obtain a mixed system.

[0095] (2) Add the mixture obtained in step (1) to 100g of silicate cement and stir evenly to obtain cement paste.

[0096] (3) Add 5g of hydrogen peroxide to the cement slurry obtained in step (2) and stir quickly for 30s to obtain cement slurry.

[0097] (4) Quickly pour the cement slurry obtained in step (4) into a cubic electrochemical test mold (1cm) with two stainless steel plates. 3 The porous cement solid electrolyte ionic conductivity test sample was obtained in the sample, and the cement slurry prepared in step (4) was poured into a cubic compressive strength test mold (64cm). 3 The test sample for compressive strength was obtained in the process.

[0098] In addition, this comparative example also provides a method for preparing a capacitor, the specific steps of which are as follows:

[0099] (1) Graphene oxide slurry with a specification of 22 mg / mL was prepared in the laboratory using the modified Hummers method. It was uniformly coated on cleaned nickel foam and dried for 2 h. Then it was transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 18 h. The product was washed twice with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain reduced graphene oxide composite material.

[0100] (2) Dissolve 0.8g of calcium stearate in 40g of deionized water, add it to 100g of silicate cement, add 5g of hydrogen peroxide, and stir evenly to obtain cement slurry.

[0101] (3) The cement slurry obtained in step (2) is poured into a cubic electrochemical testing mold (1cm) containing two pieces of reduced graphene oxide composite material. 3 To obtain cement-structured supercapacitors, it was ensured that the composite material and cement could fully contact each other to achieve effective ion transport. After casting, all test samples were placed in a standard curing room and cured in mold for 24 hours. After demolding, the samples were cured for 28 days before relevant performance tests were conducted. Before electrochemical performance testing, the cement-structured supercapacitors were immersed in a 2 mol / L KOH solution for 12 hours until saturation.

[0102] Performance testing

[0103] Figure 1 This is a schematic diagram of the synthesis process of porous cement solid electrolyte and cement structure supercapacitor in Examples 1-5 and Comparative Example 1 of the present invention.

[0104] Figure 2 SEM images of the porous cement solid electrolytes in Examples 1-5 and Comparative Example 1 are shown. The images reveal a porous structure with abundant irregular pore channels within the porous cement solid electrolytes. These channels and spaces, similar to an anthill, allow for rapid absorption and storage of KOH solution. Furthermore, the number of pores inside the cement increases with increasing potassium iodide content, further demonstrating the catalytic effect of potassium iodide and the synergistic pore-forming effect between potassium iodide and hydrogen peroxide. The reaction mechanism can be explained by equations (1) and (2):

[0105] H2O2+I - →IO - +H2O (1)

[0106] IO - +H₂O₂→O₂↑+I - +H2O (2)

[0107] Mercury intrusion porosimetry was performed on the porous cement solid electrolytes from Examples 1-5 and Comparative Example 1 after 28 days of hydration. The results are as follows:

[0108] Figure 3 (a) shows the pore size distribution of the porous cement solid electrolytes in Examples 1-5 and the cement solid electrolyte in Comparative Example 1. The sample without potassium iodide mainly exhibits a single-peak distribution. The addition of potassium iodide affected the pore size distribution of the sample: the pores in the 50-100 nm range shifted to the range greater than 1000 nm, showing a significant increasing trend. Figure 3 (b) indicates that the total pore volume of the samples increases with increasing potassium iodide content. The cumulative pore volumes of the six porous cement solid electrolytes are: Example 5 (0.317 mL / g) > Example 4 (0.313 mL / g) > Example 3 (0.274 mL / g) > Example 2 (0.271 mL / g) > Example 1 (0.253 mL / g) > Comparative Example 1 (0.181 mL / g). Correspondingly, as Figure 3 As shown in (c), the porosity of the six porous cement solid electrolytes was as follows: Example 5 (41.1%) > Example 4 (40.1%) > Example 3 (39.5%) > Example 2 (38.4%) > Example 1 (35.8%) > Comparative Example 1 (21.7%). This indicates that an appropriate amount of potassium iodide can significantly improve the pore structure of the cement solid electrolyte, and the porous structure increases the storage space and promotes K+ ionization. + and OH - Infiltration.

[0109] Figure 3 (d) represents the compressive strength of the porous cement solid electrolyte after 28 days of hydration. With increasing potassium iodide content, the compressive strength of the porous cement solid electrolyte decreased from 28.4 MPa to 15.3 MPa. Higher porosity and larger pore size may have a negative impact, thus reducing its compressive strength. Figure 3 (e) represents the ionic conductivity of the porous cement solid electrolyte in Examples 1-5 and the cement solid electrolyte in Comparative Example 1. The ionic conductivity of the six porous cement solid electrolytes is as follows: Example 4 (20.5 mS / cm) > Example 5 (16.8 mS / cm) > Example 3 (13.6 mS / cm) > Example 2 (12.7 mS / cm) > Example 1 (10.4 mS / cm) > Comparative Example 1 (7.9 mS / cm). Figure 3 (f) is a multifunctional diagram of the porous cement solid electrolyte in Examples 1-5 and Comparative Example 1. It can be seen that the multifunctionality of the porous cement solid electrolyte in Example 4 is closest to the ideal point.

[0110] To study the electrochemical performance of porous cement solid electrolyte, reduced graphene oxide was used as the positive and negative electrodes, and the solid electrolyte was assembled into a symmetrical cement structure supercapacitor.

[0111] Figure 4(a) Cyclic voltammetry curves of different cement-structured supercapacitors at a scan rate of 10 mV / s. All curves exhibit symmetrical rectangles, indicating good double-layer capacitance behavior. The area under the curve is positively correlated with the areal capacitance of the capacitor. The areal capacitance of the six capacitors is as follows: Example 4 > Example 5 > Example 3 > Example 2 > Example 1 > Comparative Example 1. The porous cement solid electrolyte-assembled supercapacitor of Example 4 has the largest areal capacitance.

[0112] Figure 4 (b) shows the cyclic voltammetry curves of different cement structure supercapacitors at different scan rates (10-200mV / s). As the scan rate increases, the shape of the curve hardly changes, indicating that it has excellent rate performance.

[0113] Figure 4 (c) Different cement-structured supercapacitors at a current density of 0.5 mA / cm² 2 The constant current charge-discharge curves were obtained. All curves exhibited an isosceles triangle shape, indicating good charge-discharge reversibility. Among them, the porous cement solid electrolyte assembled supercapacitor in Example 4 had the longest discharge time and the smallest voltage drop, which is consistent with... Figure 4 (a) The results are consistent.

[0114] Figure 4 (d) shows the supercapacitors with different cement structures at different current densities (0.5-10 mA / cm²). 2 The constant current charge-discharge curves under constant current conditions are shown. As the current density increases, the areal capacitance of the structural supercapacitor decreases, and the curves always exhibit good symmetry.

[0115] Figure 4 (e) shows the impedance diagrams of supercapacitors with different cement structures. The radius of curvature in the high-frequency region indicates the change in the internal resistance of the capacitor; the smaller the radius, the smaller the internal resistance. As can be seen from the figure, the supercapacitor assembled with porous cement solid electrolyte in Example 4 has a smaller radius of curvature, indicating a smaller internal resistance.

[0116] Figure 4 (f) shows the Bode plots of supercapacitors with different cement structures. The phase angle of the supercapacitor assembled with porous cement solid electrolyte in Example 4 is close to that of an ideal capacitor, indicating that the cement structure supercapacitor has ion diffusion behavior close to that of an ideal capacitor at low frequencies. The small relaxation time further confirms that the porous cement solid electrolyte has a fast ion transport capability.

[0117] The areal capacitance of different cement-structured supercapacitors under different current densities is as follows: Figure 4 As shown in (g), the six capacitors at 0.5 mA / cm 2The areal capacitance at current densities are as follows: Example 4 (351.5 mF / cm²) 2 Example 5 (317.5 mF / cm) 2 Example 3 (260.7 mF / cm) 2 Example 2 (243.5 mF / cm) 2 Example 1 (213.1 mF / cm) 2 ) > Comparative Example 1 (158.7 mF / cm 2 When the current density is increased to 20 times the original value, the capacitance retention rate reaches 59.9%.

[0118] The energy density and power density of the cement structure supercapacitor can be obtained through calculation and analysis of the constant current charge-discharge curves, as shown in the following results. Figure 4 As shown in (h). The structural supercapacitor assembled from the porous cement solid electrolyte of Example 4 has a maximum energy density of 21.6 Wh / kg at a power density of 110.6 W / kg and a maximum power density of 1106.2 W / kg at an energy density of 13.8 Wh / kg.

[0119] Figure 4 (i) shows the cycle stability test curves of supercapacitors with different cement structures, illustrating the performance of the porous cement solid electrolyte assembled supercapacitor in Example 4 at 10 mA / cm². 2 The areal capacitance retention rate after 5000 cycles at current density fluctuated around 93.8% during the cycle, demonstrating the good cycle stability of the cement structure supercapacitor.

[0120] In summary, this invention provides a low-cost and simple approach to constructing high-performance building energy storage devices.

[0121] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any 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 invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a porous cement solid electrolyte, characterized in that, The specific steps are as follows: S1. Dissolve potassium iodide and foam stabilizer in water and stir until homogeneous to obtain a mixed system; S2. Add the mixture obtained in step S1 to the cement and stir evenly to obtain cement paste; S3. Add foaming agent to the cement slurry obtained in step S2 and stir evenly to obtain cement slurry. S4. After pouring and curing the cement slurry obtained in step S3, a porous cement solid electrolyte is obtained (3). In step S1, the foam stabilizer is calcium stearate; In step S3, the foaming agent is hydrogen peroxide; In steps S1 to S3, the mass ratio of potassium iodide, foam stabilizer, water, cement, and foaming agent is 0.1 to 0.5: 0.8: 40: 100:

5. The porous cement solid electrolyte (3) has a porous structure with irregular pore channels inside. The porous cement solid electrolyte (3) has channels and spaces similar to those of an ant nest; The addition of potassium iodide affected the pore size distribution of the porous cement solid electrolyte (3): the pore size in the range of 50~100 nm shifted to the range of greater than 1000 nm, showing a significant increasing trend; A three-dimensional porous cement solid electrolyte was synthesized by using a chemical foaming method to create pores inside the cement, with potassium iodide as the activator and hydrogen peroxide as the foaming agent (3). This achieved effective control of the pore structure, improved the ionic conductivity of the electrolyte, and improved the interfacial contact. Potassium iodide plays a dual role: first, as an activator, it increases the porosity of the porous cement solid electrolyte (3), thereby improving the overall ionic conductivity; second, as a redox active material, it provides additional pseudocapacitance for the cement structure supercapacitor, thereby improving the electrochemical performance of the capacitor. The catalytic effect of potassium iodide and the reaction mechanism of the synergistic pore-forming effect between potassium iodide and hydrogen peroxide are explained by equations (1) and (2): H2O2+I - →IO - +H2O (1), I - +H2O2→O2↑+I - +H2O (2)。 2. The method for preparing a porous cement solid electrolyte according to claim 1, characterized in that, In step S1, the water is deionized water; In step S2, the cement is silicate cement.

3. The method for preparing a porous cement solid electrolyte according to claim 1, characterized in that, The mass ratio of potassium iodide, foam stabilizer, water, cement, and foaming agent is 0.4:0.8:40:100:

5.

4. A porous cement solid electrolyte, characterized in that, The porous cement solid electrolyte (3) is prepared by any of the preparation methods described in claims 1-3.

5. A porous cement solid electrolyte according to claim 4, characterized in that, The pore volume ranges from 0.25 to 0.35 mL / g, the porosity ranges from 21.7% to 41.1%, the average pore size ranges from 64 to 100 nm, and the dry density of the porous cement solid electrolyte ranges from 280 to 750 kg / m³. 3 .

6. An application of a porous cement solid electrolyte, characterized in that, The porous cement solid electrolyte (3) prepared by any of the preparation methods described in claims 1-3 is used to prepare cement structure supercapacitors.

7. The application of a porous cement solid electrolyte according to claim 6, characterized in that, The cement structure supercapacitor includes a metal layer (1), a reduced graphene oxide layer (2), and a porous cement solid electrolyte (3). One side of each of the two reduced graphene oxide layers (2) is connected to the upper and lower sides of the porous cement solid electrolyte (3), and the other side of each of the two reduced graphene oxide layers (2) is provided with a metal layer (1).

8. The application of a porous cement solid electrolyte according to claim 6, characterized in that, The method for preparing the cement structure supercapacitor is as follows: S1. Graphene oxide slurry is uniformly coated onto a metal, reacted at high temperature, and then washed and dried to obtain a reduced graphene oxide composite material. S2. Dissolve potassium iodide and foam stabilizer in water and stir evenly to obtain a mixed system. Add the mixed system to cement and stir evenly to obtain cement paste. Add foaming agent to cement paste and stir evenly to obtain cement slurry. S3. The cement slurry obtained in step S2 is poured between two pieces of reduced graphene oxide composite material, and after curing, a cement structure supercapacitor is obtained.

9. The application of a porous cement solid electrolyte according to claim 8, characterized in that, In step S1, the metal is nickel foam; in step S3, the curing time is 20-30 days.

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