An etching method for regulating porous cement-based separators, and a preparation method and application thereof

Abstract

The application relates to a kind of etching method for regulating porous cement-based diaphragm and its preparation method and application, and belongs to the technical field of battery diaphragm.The preparation method flow of the cement-based diaphragm includes cement neat paste test piece forming, polishing, etching and drying.The etching is to dissolve the composition of cement neat paste itself by using acid solution, improve the porosity and pore connectivity of cement neat paste, expand the transmission channel of ions, and then improve the ion conductivity of cement neat paste.The prepared cement-based diaphragm can be applied to super capacitor, hybrid super capacitor and battery.The energy storage device includes tab, positive electrode, negative electrode and cement-based diaphragm after etching and impregnated with electrolyte between two electrodes.The preparation process of the cement-based diaphragm is simple and reasonable, convenient to operate, can improve the porosity of cement neat paste, provide more channels for the transmission of ions in its interior, thereby improve the ion conductivity of cement neat paste, so that it can have better energy storage performance when used as diaphragm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery separator, in particular to a preparation method of porous cement-based separator regulated by etching method and application thereof in electrochemical energy storage. BACKGROUND

[0002] With the population explosion and deepening of industrialization, the global fossil energy is facing serious problems such as energy depletion and environmental pollution. Under this background, renewable energy represented by solar energy and wind energy ushered in new opportunities for development. However, renewable energy has the characteristics of large fluctuation, strong randomness and intermittency, which is difficult to match with the peak of electricity consumption at the peak of power generation. The energy storage system can smooth the fluctuation of new energy power generation, reduce energy waste and promote the consumption of new energy. Therefore, the development and application of energy storage technology has become the key to promote the development of renewable energy. Current energy storage technologies include mechanical energy storage, electrochemical energy storage, electromagnetic energy storage and electrochemical energy storage. Among them, electrochemical energy storage is widely used in the field of energy storage due to its advantages of reliability, economy, long service life, large capacity, less terrain restriction, flexible operation and quick response.

[0003] The electrochemical energy storage system is composed of electrodes and separators, and is assembled into a sandwich structure according to the "electrode-separator-electrode" structure. Among them, the separator separates the positive and negative electrodes to prevent short circuit and only allows ions to pass to form a charge and discharge circuit, which needs to have the basic properties of electrical insulation, high mechanical strength, rich pore structure and high ionic conductivity. However, the mechanical strength of the existing commercial electrochemical energy storage separator is not high, which is easy to be penetrated by dendrite, and then safety problems are caused. Therefore, the development of new type of separator material is an important means to promote the further development of energy storage technology and new energy.

[0004] The non-flammability, electrical insulation, high mechanical properties and porosity-rich properties of cement-based materials make them have potential as separators. The ion transport performance of cement-based separators is a key factor affecting their electrochemical energy storage. The existing methods for improving the ion transport performance of cement-based separators include adding polymers (such as polyacrylic acid PAA, polyvinyl alcohol PVA, etc.) and pore structure regulation. Polymers can provide additional channels for ion transport, but the polymers are prone to agglomeration during the incorporation process and are prone to dehydration due to the loss of pore solution, thereby causing the internal porosity of the separator to be uneven and the ion transport performance to decrease. Pore structure regulation is a method for improving the porosity of cement-based separators, increasing the pore connectivity and improving the pore size distribution, thereby improving their ion transport performance. This method is simple and convenient to operate, and the method includes changing the mixing ratio, changing the curing conditions and introducing air, etc. Changing the mixing ratio and curing conditions can only limitedly improve the porosity of the material, and its ion transport performance is still poor. Although air entraining can improve the porosity and ion transport performance of the material by introducing a large number of air bubbles, the position and size of the air bubbles are random, so the controllability of the pore structure of the material is poor. The present application provides a new pore structure regulation method, which applies etching method to cement-based separators, uses acidic solution to dissolve the composition of cement-based separators to leave holes, so as to achieve the purposes of expanding the pore size, improving the porosity and improving the pore connectivity, thereby effectively improving the ion transport performance and electrochemical energy storage performance. This method can more effectively regulate the pore structure characteristics of the cement-based separator by optimizing the water-cement ratio and mass loss of the cement paste. SUMMARY

[0005] The purpose of the present application is to provide a preparation method for regulating porous cement-based separators by etching method, which can improve the porosity and pore connectivity of cement paste, thereby improving the ion conductivity; another purpose of the present application is to provide a cement-based separator; another purpose of the present application is to provide an electrochemical energy storage device.

[0006] Technical solution: In order to solve the problems of small porosity, poor pore connectivity and low ion conductivity of existing cement-based materials, the present application provides a preparation method for regulating porous cement-based battery separators based on etching method, and applies it to electrochemical energy storage devices.

[0007] The cement-based separator of the present application has a plurality of etching pores distributed on the surface of the cement-based separator, the etching pores are obtained by etching the cement paste sheet with an acidic solution, and the mass loss of the cement paste sheet is 5-40%; the cement paste sheet is further expanded in porosity, pore size and pore connectivity by etching.

[0008] Further, the acidic solution is any one or a mixture of several of 1-5 mol / L ammonium chloride solution, 1-6 mol / L ammonium nitrate solution or 0.1-1 mol / L hydrochloric acid solution.

[0009] Further, the composition of the etched cement paste slice includes one or more of calcium silicate hydrate, calcium hydroxide, calcium carbonate, ettringite, etc.

[0010] In another aspect, the present application provides a method for preparing the above-mentioned cement-based separator, wherein the cement paste slice is first soaked in water and placed in a negative pressure environment to be fully saturated with water, then the saturated cement paste slice is soaked in an acidic solution to etch away the composition of the cement paste, the mass loss of the cement paste slice is monitored, the etched cement paste slice is soaked in water to remove the etching solution, and then dried to obtain the cement-based separator.

[0011] Further, the soaking time in water is 1-3 days, and the negative pressure is -0.05 to -0.1 MPa.

[0012] Further, the water-cement ratio of the cement paste is 0.3-0.7, preferably 0.5; the stirring time is 60-90 seconds, the temperature of the curing chamber is 18-22°C, the relative humidity is above 95%, and the age is 1-180 days, preferably 28-56 days.

[0013] Further, the soaking time in water is 1-7 days; the drying is one or more of natural drying, vacuum drying, freeze-drying, or microwave drying, and the drying time is 1-14 days.

[0014] Specifically, the method for preparing the above-mentioned cement-based separator includes the following steps:

[0015] (1) Preparation of cement paste slice: cement and water are mixed and stirred, poured into a mold, and polished after curing to obtain a cement paste slice;

[0016] (2) Acidic solution etching: the cement paste slice is first soaked in water and placed in a negative pressure environment to be fully saturated with water, then the saturated cement paste slice is soaked in an acidic solution to etch away the composition of the cement paste, the mass loss of the cement paste slice is monitored, and a cement-based separator with a desired porosity is obtained;

[0017] (3) Drying: the etched cement paste slice is soaked in water to remove the etching solution, and then dried to obtain the cement-based separator.

[0018] Further, in step (1), the polishing method is one or more of sandpaper, automatic polishing machine, and manual polishing machine.

[0019] Further, in step (1), the thickness of the cement paste slice is 0.4-5.0 mm.

[0020] In another aspect, the present application provides an electrochemical energy storage device, which comprises the cement-based separator, two tabs, a positive electrode and a negative electrode, wherein the tabs are respectively fixedly connected with the positive and negative electrodes, and the cement-based separator is immersed in an electrolyte under negative pressure and is arranged between the positive and negative electrodes to form a sandwich structure.

[0021] Further, the cement-based separator is sealed after forming the sandwich structure with the positive and negative electrodes, and the sealing method is one of vacuum packaging, epoxy coating and paraffin coating.

[0022] Further, the material of the tabs is one or more of aluminum, stainless steel, nickel and titanium.

[0023] Further, the electrolyte immersion time is 1-28 days.

[0024] Further, the electrolyte is one or more of soluble salt solutions of zinc sulfate, zinc acetate, zinc nitrate, manganese sulfate, potassium hydroxide and sodium hydroxide.

[0025] Further, the positive and negative electrodes are metal foils (zinc, copper, platinum, etc.) or active material electrodes.

[0026] Further, the specific manufacturing method of the active material electrode is as follows: the active material, the conductive agent and the binder are put into a mortar and fully ground and mixed, then N-methyl pyrrolidone is added for rapid stirring, and finally the obtained slurry is uniformly coated on a carrier with conductivity, and dried to obtain the active material electrode.

[0027] Specifically, the specific manufacturing method of the active material electrode is as follows: the active material, the conductive agent and the binder are put into a mortar according to the mass ratio and fully ground and mixed, then N-methyl pyrrolidone is added for rapid stirring according to the liquid-solid mass ratio, and finally the obtained slurry is uniformly coated on a carrier with conductivity and is put into a blast drying oven for drying.

[0028] Further, the active material is one or more of activated carbon, graphene, redox graphene, manganese dioxide or nano carbon black.

[0029] Further, the conductive agent is one or more of acetylene black, ketjen black, conductive graphite or nano carbon fiber.

[0030] Further, the binder is one or more of polyvinylidene fluoride, sodium alginate, polyvinyl alcohol and hydroxymethyl cellulose.

[0031] Further, the mass ratio is (75-85):(5-15):(5-15), and preferably the mass ratio is 8:1:1.

[0032] Further, the liquid-solid mass ratio is 2-7.

[0033] Further, the slurry is uniformly scraped by a doctor blade, a spatula, a four-blade wet film maker or an automatic coating machine.

[0034] Further, the carrier is one or more of foil, mesh or foam of stainless steel, copper, titanium, nickel and the like.

[0035] Further, the loading of the active substance is 0.5-30 mg / cm 2 .

[0036] Further, the drying temperature is 55-65 DEG C, and the drying time is 4-36 h.

[0037] Advantages: compared with the prior art, the present application has the following remarkable advantages: (1) the cement paste is a composite material composed of various phases, the constituent phases are easily dissolved by acid, when the pore structure of the cement paste is regulated by etching, the constituent phases of the cement paste can be used as pore-forming agents, without adding additional pore-forming agents, and then the pores are left by dissolving the pore-forming agents with acid solution, so that the process is simplified;

[0038] (2) compared with static water etching, the acid solution etching can quickly dissolve part of the constituent components of the cement paste, thereby saving time;

[0039] (3) the present application regulates the pore structure of the cement-based separator from a microscopic point of view, the acid solution etching can improve the porosity and pore connectivity of the cement paste, expand the ion transmission channel, and thus improve the ion conductivity of the cement paste, thereby effectively improving the energy storage characteristics of the material, providing a new idea for relieving the energy crisis;

[0040] (4) by optimizing the water-cement ratio, age, thickness and mass loss of the cement paste, the pore structure parameters of the cement-based separator can be effectively regulated, and the application prospect is broad;

[0041] (5) the method of the present application is simple and reasonable, easy to operate, low in raw material cost, environment-friendly, and has good economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The structure of the energy storage device provided by the present application is shown in the figure, wherein 1 is an ear, 2 is a positive electrode, 3 is a negative electrode, 4 is a cement-based separator, and 5 is an energy storage device.

[0043] Figure 2 The AC impedance spectrum, charge-discharge curve and long cycle of the obtained example 1 are shown in the figure.

[0044] Figure 3Fig. 2 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 2 obtained by using the present application;

[0045] Figure 4 Fig. 3 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 3 obtained by using the present application;

[0046] Figure 5 Fig. 4 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 4 obtained by using the present application;

[0047] Figure 6 Fig. 5 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 5 obtained by using the present application;

[0048] Figure 7 Fig. 6 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 6 obtained by using the present application;

[0049] Figure 8 Fig. 7 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 7 obtained by using the present application;

[0050] Figure 9 Fig. 8 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 8 obtained by using the present application;

[0051] Figure 10 Fig. 9 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 9 obtained by using the present application;

[0052] Figure 11 Fig. 10 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 10 obtained by using the present application;

[0053] Figure 12 Fig. 11 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 11 obtained by using the present application;

[0054] Figure 13 Fig. 12 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 12 obtained by using the present application;

[0055] Figure 14 Fig. 13 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 13 obtained by using the present application;

[0056] Figure 15 Fig. 14 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 14 obtained by using the present application;

[0057] Figure 16 Fig. 15 is an AC impedance spectrum, charge-discharge curve and long cycle of Example 15 obtained by using the present application;

[0058] Figure 17To utilize the AC impedance spectrum, charge-discharge curves, and long-cycle data of Example 16 obtained by the present invention;

[0059] Figure 18 The AC impedance spectrum, charge-discharge curves, and long-cycle data of Example 17 obtained by utilizing the present invention are presented. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] like Figure 1 As shown, an embodiment of the present invention provides an electrochemical energy storage device 5, including a tab 1, a positive electrode 2, a negative electrode 3, and a cement-based diaphragm 4, which is etched between the two electrodes and wetted with electrolyte; wherein the tab 1 is fixedly connected to the positive electrode 2 and the negative electrode 3 respectively, the cement-based diaphragm 4 is immersed in electrolyte under negative pressure and placed between the positive electrode 2 and the negative electrode 3 to form a sandwich structure, and the positive and negative electrodes are made of metal foil or active material.

[0062] Example 1

[0063] Preparation of cement-based diaphragm: Deionized water and silicate cement were mixed in a mixing pot at a water-cement ratio of 0.5 for 60 seconds, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the mixture was demolded and cured for 5 days in a curing room at a temperature of 20±2℃ and a relative humidity of over 95%. The specimen was ground into a 1.0 mm thin sheet, soaked in deionized water for 1 day, and then placed in a 0.1 mol / L hydrochloric acid solution. The mass of the specimen was weighed every 30 minutes, and the mass loss was calculated until the mass loss of the specimen reached 5%. Finally, the specimen was dried in a vacuum drying oven at 45℃ for 7 days to obtain a cement-based diaphragm with a porosity of 40.4%.

[0064] Zinc electrode fabrication: Zinc foil is cut into zinc electrodes with a diameter of 12mm using a tablet press.

[0065] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 minutes. 1800 μL of N-methylpyrrolidone was added to the mortar, and the mixture was rapidly stirred to obtain a slurry. The slurry was evenly coated onto a 200-mesh stainless steel mesh using a 10 μm coating tool, and then dried in a 60℃ forced-air drying oven for 24 hours. The dried material was then cut into 12 mm diameter activated carbon electrodes using a tablet press, with an activated carbon loading of approximately 2.45 mg / cm³. 2 .

[0066] Energy storage device: The activated carbon electrode was used as the positive electrode, the zinc electrode was used as the negative electrode, and the cement-based separator was soaked in zinc sulfate solution to form a hybrid supercapacitor. The dried cement-based separator was immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 Mpa for 14 days. First, the tabs were fixed to the positive and negative electrodes, then the cement-based separator soaked with electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 2 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and the ionic conductivity of the cement-based separator was calculated to be 0.29 S / m. The maximum specific capacity was 66.9 mWh / g, and the energy attenuation was 13.1% after 220 cycles.

[0067] Example 2

[0068] The difference between the cement-based separator of this example and that of Example 1 is that the cement-based separator of this example is cured for 7 days, and the acid etching solution is 1.25 mol / L ammonium nitrate solution, and the mass loss of the test piece is 20%. The energy storage device of this example is the same as that of Example 1.

[0069] Cement-based separator preparation: Deionized water and Portland cement were mixed in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the test piece was removed from the mold and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days. The test piece was polished to a thickness of 1.0 mm and immersed in deionized water for 1 day, then placed in a 1.25 mol / L ammonium nitrate solution. The mass of the test piece was measured every 30 min and the mass loss was calculated until the mass loss of the test piece reached 20%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 67.4%.

[0070] Zinc electrode preparation: The zinc foil was cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0071] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 1800 μL of N-methyl pyrrolidone was added to the mortar and stirred quickly to obtain a slurry. The slurry was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), then placed in a 60℃ air drying oven for 24 h. The coated mesh was cut into activated carbon electrodes with a diameter of 12 mm using a tablet press, and the activated carbon loading was about 2.45 mg / cm 2 .

[0072] Energy storage device: the activated carbon electrode as the positive electrode, zinc electrode as the negative electrode, and the cement-based separator soaked in zinc sulfate solution to form a hybrid supercapacitor. Dry the cement-based separator and immerse it in 2 mol / L zinc sulfate solution for 14 days in a negative pressure environment of -0.1 Mpa. First, connect the tabs to the positive and negative electrodes, then place the cement-based separator soaked in electrolyte between the two electrodes, and fix it with adhesive tape to form a sandwich structure. Finally, test the AC impedance spectrum under the condition of test frequency range 0.1-10 6 Hz, see Figure 3 ; test the constant current charge and discharge performance and cycle performance of the hybrid capacitor under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and calculate the ionic conductivity of the cement-based separator as 0.47 S / m. The maximum specific capacity is 102 mWh / g, and the energy attenuation is 13.4% after 340 cycles.

[0073] Example 3

[0074] The difference between this example and the cement-based separator of Example 1 is that the cement-based separator of this example is cured for 7 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the sample is 20%. The energy storage device of this example is the same as that of Example 1.

[0075] Cement-based separator preparation: deionized water and Portland cement are mixed in a ratio of water-cement ratio 0.5 in a stirring pot for 60 s, then poured into a mold with inner diameter 13 mm and depth 5 mm, demolded after hardening for 1 day, and cured in a curing room with temperature 20±2℃ and relative humidity above 95% for 7 days. The sample is polished into a 1 mm thick sheet, immersed in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution, and its mass is measured every 30 min to calculate the mass loss until the mass loss of the sample reaches 20%. Finally, dry the cement-based separator in a vacuum drying oven at 45℃ for 7 days to obtain a cement-based separator with porosity of 64.1%.

[0076] Zinc electrode preparation: use a tablet press to cut zinc foil into a zinc electrode with a diameter of 12 mm.

[0077] Activated carbon electrode preparation: put 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride into a mortar and grind for 10 min, add 1800 μL of N-methyl pyrrolidone to the mortar, and quickly stir to obtain a slurry. Use a film applicator (10 μm) to evenly coat the slurry on a 200 mesh stainless steel mesh, then place it in a 60℃ air drying oven for 24 h, and use a tablet press to cut it into an activated carbon electrode with a diameter of 12 mm. The activated carbon loading is about 2.45 mg / cm 2 .

[0078] Energy storage device: the activated carbon electrode as the positive electrode, zinc electrode as the negative electrode, and the cement-based separator soaked in zinc sulfate solution to form a hybrid supercapacitor. The dry cement-based separator was immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 Mpa for 14 days. First, the tab was fixed to the positive and negative electrodes, then the cement-based separator soaked with electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the alternating current impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 4 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and the calculated ionic conductivity of the cement-based separator was 0.51 S / m. The maximum specific capacity was 69.9 mWh / g, and the energy attenuation was 10.4% after 1050 cycles.

[0079] Example 4

[0080] The difference between this example and the cement-based separator of Example 1 is that the cement-based separator of this example is cured for 7 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 28%. The energy storage device of this example is the same as that of Example 1.

[0081] Cement-based separator preparation: deionized water and Portland cement were mixed in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the test piece was removed and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days. The test piece was polished to a thickness of 1.0 mm and immersed in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution. The mass of the test piece was measured every 30 min and the mass loss was calculated until the mass loss of the test piece reached 28%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 68.5%.

[0082] Zinc electrode preparation: zinc foil was cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0083] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 1800 μL of N-methyl pyrrolidone was added to the mortar and stirred quickly to obtain a slurry. The slurry was uniformly coated on a 200 mesh stainless steel mesh using a film applicator (10 μm), then placed in a 60℃ air drying oven for 24 h. The coated mesh was cut into activated carbon electrodes with a diameter of 12 mm using a tablet press, and the activated carbon loading was about 2.45 mg / cm 2 .

[0084] Energy storage device: the activated carbon electrode as the positive electrode, zinc electrode as the negative electrode, and the cement-based separator soaked in zinc sulfate solution to form a hybrid supercapacitor. The dry cement-based separator was immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of-0.1 Mpa for 14 days. First, the tab was fixed to the positive and negative electrodes, then the cement-based separator soaked with electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 5 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and the calculated ionic conductivity of the cement-based separator was 1.39 S / m. The maximum specific capacity was 89.9 mWh / g, and the energy attenuation was 20.4% after 925 cycles.

[0085] Example 5

[0086] The difference between this example and the cement-based separator of Example 1 is that the cement-based separator of this example is cured for 7 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 14%. The energy storage device of this example is the same as that of Example 1.

[0087] Cement-based separator preparation: deionized water and Portland cement were mixed in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the test piece was removed and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days. The test piece was polished to a thickness of 1.0 mm and immersed in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution. The mass of the test piece was measured every 30 min and the mass loss was calculated until the mass loss of the test piece reached 14%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 55.9%.

[0088] Zinc electrode preparation: zinc foil was cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0089] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 1800 μL of N-methyl pyrrolidone was added to the mortar and stirred quickly to obtain a slurry. The slurry was evenly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), then placed in a 60℃ air drying oven for 24 h. The coated mesh was cut into activated carbon electrodes with a diameter of 12 mm using a tablet press, and the activated carbon loading was about 2.45 mg / cm 2 .

[0090] Energy storage device: An activated carbon electrode is used as the positive electrode, a zinc electrode as the negative electrode, and a cement-based diaphragm is soaked in zinc sulfate solution to form a hybrid supercapacitor. The dried cement-based diaphragm is immersed in a 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 MPa for 14 days. First, the electrode tabs are fixedly connected to the positive and negative electrodes. Then, the electrolyte-soaked cement-based diaphragm is placed between the two electrodes, secured with tape to form a sandwich structure, and sealed. Finally, the test frequency range is 0.1–10 Hz. 6 The AC impedance spectrum was tested under Hz conditions, see [reference needed]. Figure 6 Within the voltage window of 0.2–1.8V, the current density is 0.4 mA / cm². 2 The constant current charge-discharge performance and cycle performance of the hybrid capacitor were tested under the specified conditions. The calculated ionic conductivity of the cement-based diaphragm was 0.364 S / m. The maximum specific capacity was 69 mWh / g, and the energy decay was 7.2% after 850 cycles.

[0091] Example 6

[0092] The difference between this embodiment and the cement-based diaphragm fabrication in Embodiment 1 is that in this embodiment, the diaphragm was cured for 7 days, and the acid etching solution was a 4 mol / L ammonium chloride solution, resulting in a mass loss of 18% for the specimen. The energy storage device setup in this embodiment is the same as in Embodiment 1.

[0093] Preparation of cement-based diaphragm: Deionized water and silicate cement were mixed in a mixing pot at a water-cement ratio of 0.5 for 60 seconds, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the mixture was demolded and cured for 7 days in a curing room at a temperature of 20±2℃ and a relative humidity of over 95%. The specimen was ground into a 1.0 mm thin sheet, soaked in deionized water for 1 day, and then placed in a 4 mol / L ammonium chloride solution. The mass of the specimen was weighed every 30 minutes, and the mass loss was calculated until the mass loss of the specimen reached 18%. Finally, the specimen was dried in a vacuum drying oven at 45℃ for 7 days to obtain a cement-based diaphragm with a porosity of 61%.

[0094] Zinc electrode fabrication: Zinc foil is cut into zinc electrodes with a diameter of 12mm using a tablet press.

[0095] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 minutes. 1800 μL of N-methylpyrrolidone was added to the mortar, and the mixture was rapidly stirred to obtain a slurry. The slurry was evenly coated onto a 200-mesh stainless steel mesh using a 10 μm coating tool, and then dried in a 60℃ forced-air drying oven for 24 hours. The dried material was then cut into 12 mm diameter activated carbon electrodes using a tablet press, with an activated carbon loading of approximately 2.45 mg / cm³. 2 .

[0096] Energy storage device: the activated carbon electrode as the positive electrode, the zinc electrode as the negative electrode, and the cement-based separator soaked in zinc sulfate solution to form a hybrid supercapacitor. The dry cement-based separator was immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 Mpa for 14 days. First, the tab was fixed to the positive and negative electrodes, then the cement-based separator soaked in electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 7 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and the calculated ionic conductivity of the cement-based separator was 0.492 S / m. The maximum specific capacity was 79.6 mWh / g, and the energy attenuation was 4.1% after 800 cycles.

[0097] Example 7

[0098] The difference between this example and the cement-based separator of Example 1 is that the cement-based separator of this example is cured for 7 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 24%. The energy storage device of this example is the same as that of Example 1.

[0099] Cement-based separator preparation: deionized water and Portland cement were mixed in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm, demolded after hardening for 1 day, and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 7 days. The test piece was polished into a 1.0 mm thick sheet, immersed in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution, and its mass was measured every 30 min to calculate the mass loss until the mass loss of the test piece reached 24%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 62.3%.

[0100] Zinc electrode preparation: zinc foil was cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0101] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride were put into a mortar and ground for 10 min, 1800 μL of N-methyl pyrrolidone was added to the mortar, and fast stirring was performed to obtain a slurry. The slurry was uniformly coated on a 200 mesh stainless steel mesh using a film applicator (10 μm), then placed in a 60℃ air drying oven for drying for 24 h, and cut into an activated carbon electrode with a diameter of 12 mm using a tablet press. The activated carbon loading was about 2.45 mg / cm 2 .

[0102] Energy storage device: An activated carbon electrode is used as the positive electrode, a zinc electrode as the negative electrode, and a cement-based diaphragm is soaked in zinc sulfate solution to form a hybrid supercapacitor. The dried cement-based diaphragm is immersed in a 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 MPa for 14 days. First, the electrode tabs are fixedly connected to the positive and negative electrodes. Then, the electrolyte-soaked cement-based diaphragm is placed between the two electrodes, secured with tape to form a sandwich structure, and sealed. Finally, the test frequency range is 0.1–10 Hz. 6 The AC impedance spectrum was tested under Hz conditions, see [reference needed]. Figure 8 Within the voltage window of 0.2–1.8V, the current density is 0.4 mA / cm². 2 The constant current charge-discharge performance and cycle performance of the hybrid capacitor were tested under the specified conditions. The calculated ionic conductivity of the cement-based diaphragm was 0.834 S / m. The maximum specific capacity was 86.7 mWh / g, and the energy decay was 7% after 948 cycles.

[0103] Example 8

[0104] The difference between this embodiment and the cement-based diaphragm fabrication in Embodiment 1 is that in this embodiment, the diaphragm was cured for 14 days, and the acid etching solution was a 4 mol / L ammonium chloride solution, resulting in a 24% mass loss of the specimen. The energy storage device setup in this embodiment is the same as in Embodiment 1.

[0105] Preparation of cement-based diaphragm: Deionized water and silicate cement were mixed in a mixing pot at a water-cement ratio of 0.5 for 60 seconds, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the mixture was demolded and cured for 14 days in a curing room at a temperature of 20±2℃ and a relative humidity of over 95%. The specimen was ground into a 1.0 mm thin sheet, soaked in deionized water for 1 day, and then placed in a 4 mol / L ammonium chloride solution. The mass was weighed every 30 minutes, and the mass loss was calculated until the mass loss of the specimen reached 24%. Finally, the cement-based diaphragm was dried in a vacuum drying oven at 45℃ for 7 days to obtain a porosity of 69%.

[0106] Zinc electrode fabrication: Zinc foil is cut into zinc electrodes with a diameter of 12mm using a tablet press.

[0107] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 minutes. 1800 μL of N-methylpyrrolidone was added to the mortar, and the mixture was rapidly stirred to obtain a slurry. The slurry was evenly coated onto a 200-mesh stainless steel mesh using a 10 μm coating tool, and then dried in a 60℃ forced-air drying oven for 24 hours. The dried material was then cut into 12 mm diameter activated carbon electrodes using a tablet press, with an activated carbon loading of approximately 2.45 mg / cm³. 2 .

[0108] Energy storage device: the activated carbon electrode as the positive electrode, zinc electrode as the negative electrode, zinc sulfate soaked cement-based separator, the composition of hybrid supercapacitor. The dry cement-based separator was immersed in 2 mol / L zinc sulfate solution, and placed in a negative pressure environment of-0.1Mpa for 14d. First, the tab was fixed with the positive and negative electrodes, then the cement-based separator soaked with electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 9 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8V and current density 0.4mA / cm 2 , and the calculated ionic conductivity of the cement-based separator was 0.98S / m. The maximum specific capacity was 83.8Wh / g, and the energy attenuation was 6% after 984 cycles.

[0109] Example 9

[0110] The difference between this example and the cement-based separator of example 1 is that the curing time of this example is 14d, and the acid etching solution is 4mol / L ammonium chloride solution, and the mass loss of the sample is 28%. The energy storage device of this example is the same as that of example 1.

[0111] Cement-based separator preparation: deionized water and Portland cement were mixed in a ratio of water-cement ratio 0.5 in a stirring pot for 60s, then poured into a mold with inner diameter 13mm and depth 5mm, demolded after hardening 1d, and cured in a curing room with temperature 20±2℃ and relative humidity above 95% for 14d. The sample was polished into a 1.0mm thin sheet, immersed in deionized water for 1d, then placed in a 4mol / L ammonium chloride solution, and its mass was measured every 30min to calculate the mass loss until the mass loss of the sample reached 28%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7d, and the porosity was 70%.

[0112] Zinc electrode preparation: zinc foil was cut into a zinc electrode with a diameter of 12mm using a tablet press.

[0113] Activated carbon electrode preparation: 400mg of activated carbon, 50mg of acetylene black and 50mg of polyvinylidene fluoride were put into a mortar and ground for 10min, 1800μL of N-methyl pyrrolidone was added to the mortar, and fast stirring was carried out to obtain a slurry. The slurry was uniformly coated on a 200 mesh stainless steel mesh using a film applicator(10μm), and then placed in a 60℃ air drying oven for drying for 24h. The coated mesh was cut into activated carbon electrodes with a diameter of 12mm using a tablet press, and the activated carbon loading was about 2.45mg / cm 2 .

[0114] Energy storage device: An activated carbon electrode is used as the positive electrode, a zinc electrode as the negative electrode, and a cement-based diaphragm soaked in zinc sulfate is used to form a hybrid supercapacitor. The dried cement-based diaphragm is immersed in a 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 MPa for 14 days. First, the tabs are fixedly connected to the positive and negative electrodes. Then, the electrolyte-soaked cement-based diaphragm is placed between the two electrodes, secured with tape to form a sandwich structure, and sealed. Finally, the test frequency range is 0.1–10 Hz. 6 The AC impedance spectrum was tested under Hz conditions, see [reference needed]. Figure 10 Within the voltage window of 0.2–1.8V, the current density is 0.4 mA / cm². 2 Under certain conditions, the constant current charge-discharge performance and cycle performance of the hybrid capacitor were tested, and the calculated ionic conductivity of the cement-based diaphragm was 1.465 S / m. The maximum specific capacity was 84.1 mWh / g, and the energy decay was 9.2% after 989 cycles.

[0115] Example 10

[0116] The difference between this embodiment and the cement-based diaphragm fabrication in Embodiment 1 is that: in this embodiment, the diaphragm was cured for 28 days, the specimen was polished into a 0.8 mm thin sheet, and the acid etching solution was a 4 mol / L ammonium chloride solution, resulting in a 16% mass loss of the specimen. The energy storage device setup in this embodiment is the same as in Embodiment 1.

[0117] Preparation of cement-based diaphragm: Deionized water and silicate cement were mixed in a mixing pot at a water-cement ratio of 0.5 for 60 seconds, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the mixture was demolded and cured in a curing room at a temperature of 20±2℃ and a relative humidity of over 95% for 28 days. The specimen was ground into a 0.8 mm thin sheet, soaked in deionized water for 1 day, and then placed in a 4 mol / L ammonium chloride solution. The mass of the specimen was weighed every 30 minutes, and the mass loss was calculated until the mass loss of the specimen reached 16%. Finally, the cement-based diaphragm was dried in a vacuum drying oven at 45℃ for 7 days to obtain a porosity of 56.3%.

[0118] Zinc electrode fabrication: Zinc foil is cut into zinc electrodes with a diameter of 12mm using a tablet press.

[0119] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 minutes. 1800 μL of N-methylpyrrolidone was added to the mortar, and the mixture was rapidly stirred to obtain a slurry. The slurry was evenly coated onto a 200-mesh stainless steel mesh using a 10 μm coating tool, and then dried in a 60℃ forced-air drying oven for 24 hours. The dried material was then cut into 12 mm diameter activated carbon electrodes using a tablet press, with an activated carbon loading of approximately 2.45 mg / cm³. 2 .

[0120] Energy storage device: the activated carbon electrode as the positive electrode, zinc electrode as the negative electrode, zinc sulfate soaked cement-based separator, the composition of hybrid supercapacitor. The dry cement-based separator was immersed in 2 mol / L zinc sulfate solution, and placed in a negative pressure environment of-0.1Mpa for 14d. First, the tab was fixed with the positive and negative electrodes, then the cement-based separator soaked with electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the test frequency range was 0.1-10 6 Hz, and the AC impedance spectrum was tested, see Figure 11 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8V and current density 0.4mA / cm 2 , and the ionic conductivity of the cement-based separator was calculated to be 0.39S / m. The maximum specific capacity was 85.8mWh / g, and the energy attenuation was 15% after 270 cycles.

[0121] Example 11

[0122] The difference between this example and the cement-based separator of example 1 is that this example is cured for 28d, the test piece is polished into a 0.8mm thin piece, and the acid etching solution is 4mol / L ammonium chloride solution, and the mass loss of the test piece is 30%. The energy storage device of this example is the same as that of example 1.

[0123] Cement-based separator preparation: deionized water and Portland cement were stirred in a stirring pot at a water-cement ratio of 0.5 for 60s, then poured into a mold with an inner diameter of 13mm and a depth of 5mm, demolded after hardening for 1d, and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 28d. The test piece was polished into a 0.8mm thin piece, immersed in deionized water for 1d, then placed in a 4mol / L ammonium chloride solution, and its mass was measured every 30min to calculate the mass loss until the mass loss of the test piece reached 30%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7d, and the porosity was 70.1%.

[0124] Zinc electrode preparation: zinc foil was cut into a zinc electrode with a diameter of 12mm using a tablet press.

[0125] Activated carbon electrode preparation: 400mg of activated carbon, 50mg of acetylene black and 50mg of polyvinylidene fluoride were put into a mortar and ground for 10min, 1800μL of N-methyl pyrrolidone was added to the mortar, and fast stirring was carried out to obtain a slurry. The slurry was uniformly coated on a 200 mesh stainless steel mesh using a film applicator (10μm), and then placed in a 60℃ air drying oven for drying for 24h. The slurry was cut into an activated carbon electrode with a diameter of 12mm using a tablet press, and the activated carbon loading was about 2.45mg / cm 2 .

[0126] Energy storage device: activated carbon electrode as positive electrode, zinc electrode as negative electrode, cement-based separator soaked in zinc sulfate solution, to form a hybrid supercapacitor. Dry cement-based separator was immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 Mpa for 14 days. First, the tab was fixed to the positive and negative electrodes, then the cement-based separator soaked in electrolyte was placed between the two electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 12 ; the constant current charge and discharge performance and cycle performance of the hybrid capacitor were tested under the condition of voltage window 0.2-1.8 V and current density 0.4 mA / cm 2 , and the calculated ionic conductivity of the cement-based separator was 1.42 S / m. The maximum specific capacity was 92 mWh / g, and the energy attenuation was 5% after 110 cycles.

[0127] Example 12

[0128] The difference between the cement-based separator of this example and that of Example 1 is that the cement-based separator of this example is cured for 28 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 20%.

[0129] The difference between the energy storage device of this example and that of Example 1 is that activated carbon electrode is used as positive and negative electrode, and cement-based separator is soaked in potassium hydroxide solution to form a supercapacitor.

[0130] Cement-based separator preparation: deionized water and Portland cement were mixed in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the test piece was removed from the mold and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 28 days. The test piece was polished to a thickness of 1 mm and immersed in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution. The mass of the test piece was measured every 30 min and the mass loss was calculated until the mass loss of the test piece reached 20%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 58.2%.

[0131] Activated carbon electrode preparation: 400 mg of activated carbon, 50 mg of acetylene black and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 1800 μL of N-methyl pyrrolidone was added to the mortar and stirred quickly to obtain a slurry. The slurry was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), then placed in a 60℃ air drying oven for 24 h. The activated carbon electrode was cut into a diameter of 12 mm using a tablet press, and the activated carbon loading was about 2.45 mg / cm 2 .

[0132] The energy storage device was prepared by using activated carbon electrode as positive and negative electrode, and soaking the cement-based separator in potassium hydroxide solution to form a supercapacitor. The dried cement-based separator was soaked in 2 mol / L potassium hydroxide solution and placed in a negative pressure environment of-0.1 Mpa for 14 days. First, the tab was connected to the electrode, then the cement-based separator soaked with electrolyte was placed between the positive and negative electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 13 ; the constant current charge and discharge performance and cycle performance of the supercapacitor were tested under the condition of voltage window 0-1.0 V and current density 0.4 mA / cm 2 , see Figure 13 and Figure 13 . According to Figure 13 , the ionic conductivity of the cement-based separator was calculated to be 3.69 S / m. According to Figure 13 , the maximum specific capacity was 17.3 mWh / g, and the energy attenuation was 46% after 880 cycles.

[0133] Example 13

[0134] The difference between the cement-based separator of this example and that of Example 1 is that the cement-based separator of this example is cured for 28 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 24%.

[0135] The difference between the energy storage device of this example and that of Example 1 is that the energy storage device of this example uses manganese dioxide electrode as positive electrode, graphene electrode as negative electrode, and potassium hydroxide solution to soak the cement-based separator to form a supercapacitor.

[0136] Cement-based separator preparation: deionized water and Portland cement were stirred in a stirring pot at a water-cement ratio of 0.5 for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 day, the test piece was removed from the mold and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 28 days. The test piece was polished to a thickness of 1 mm and soaked in deionized water for 1 day, then placed in a 4 mol / L ammonium chloride solution. The mass of the test piece was measured every 30 min and the mass loss was calculated until the mass loss of the test piece reached 24%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 days, and the porosity was 60.5%.

[0137] MnO2 electrode fabrication: 350 mg MnO2, 100 mg acetylene black and 50 mg polyvinylidene fluoride were put into a mortar and ground for 10 min, 1700 μL N-methyl pyrrolidone was added into the mortar and stirred quickly to get a slurry. The slurry was uniformly coated on a 200-mesh stainless steel net using a film applicator (10 μm) and then put into a 60 °C air-drying oven for drying for 24 h. The dried product was cut into MnO2 electrodes with a diameter of 12 mm using a tablet press, and the active carbon loading of the electrodes was about 1.05 mg / cm2. 2 .

[0138] Graphene electrode fabrication: 400 mg graphene, 50 mg acetylene black and 50 mg polyvinylidene fluoride were put into a mortar and ground for 10 min, 2000 μL N-methyl pyrrolidone was added into the mortar and stirred quickly to get a slurry. The slurry was uniformly coated on a 200-mesh stainless steel net using a film applicator (10 μm) and then put into a 60 °C air-drying oven for drying for 24 h. The dried product was cut into graphene electrodes with a diameter of 12 mm using a tablet press, and the active carbon loading of the electrodes was about 1.63 mg / cm2. 2 .

[0139] Energy storage device: the MnO2 electrode was used as the positive electrode, the graphene electrode was used as the negative electrode, and the cement-based separator soaked in potassium hydroxide solution was used to form a supercapacitor. The dried cement-based separator was immersed in a 6 mol / L potassium hydroxide solution and placed in a negative pressure environment of -0.1 MPa for 14 d. First, the tabs were fixed to the electrodes, and then the cement-based separator soaked in the electrolyte was placed between the positive and negative electrodes, and the sandwich structure was formed by fixing with adhesive tape. Finally, the AC impedance spectrum was tested under the condition of a test frequency range of 0.1-10 Hz, 6 . Figure 14 ; the constant current charge and discharge performance and the cycle performance of the supercapacitor were tested under the condition of a voltage window of 0-1.0 V and a current density of 0.4 mA / cm2, 2 . Figure 14 and Figure 14 . According to Figure 14 , the ionic conductivity of the cement-based separator was calculated to be 5.89 S / m. According to Figure 14 , the maximum specific capacity was 13.6 mWh / g, and the energy attenuation was 25% after 1140 cycles.

[0140] Example 14

[0141] The cement-based separator of this example was prepared by the same steps as those of Example 13, and the porosity of the obtained cement-based separator was slightly different, which was caused by different experimental batches.

[0142] The difference between the energy storage device of this example and that of Example 13 was that the graphene electrode was used as the positive electrode, the activated carbon electrode was used as the negative electrode, and the cement-based separator soaked in potassium hydroxide solution was used to form a supercapacitor.

[0143] Cement-based separator fabrication: Deionized water and Portland cement were mixed in a ratio of water to cement of 0.5 in a stirring pot for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 d, the mold was removed and the specimen was cured in a curing room at a temperature of 20 ± 2 °C and a relative humidity of 95% or more for 28 d. The specimen was ground into a 1 mm-thick slice, immersed in deionized water for 1 d, and then placed in a 4 mol / L ammonium chloride solution. The mass of the specimen was measured every 30 min and the mass loss was calculated until the mass loss of the specimen reached 24%. Finally, the specimen was dried in a vacuum drying oven at 45 °C for 7 d to obtain a cement-based separator with a porosity of 61.1%.

[0144] Graphene electrode fabrication: 400 mg of graphene, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 2000 μL of N-methyl pyrrolidone was added to the mortar and stirred rapidly to obtain a slurry. The slurry was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), and then dried in a 60 °C air-drying oven for 24 h. The graphene electrode was cut into a 12 mm-diameter graphene electrode using a tablet press, and the active carbon loading was about 1.63 mg / cm 2 .

[0145] Activated carbon electrode fabrication: 400 mg of activated carbon, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were placed in a mortar and ground for 10 min. 1800 μL of N-methyl pyrrolidone was added to the mortar and stirred rapidly to obtain a slurry. The slurry was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), and then dried in a 60 °C air-drying oven for 24 h. The activated carbon electrode was cut into a 12 mm-diameter activated carbon electrode using a tablet press, and the activated carbon loading was about 2.45 mg / cm 2 .

[0146] Energy storage device: A graphene electrode was used as the positive electrode, an activated carbon electrode was used as the negative electrode, and a cement-based separator was soaked in a potassium hydroxide solution to form a supercapacitor. The dried cement-based separator was immersed in a 6 mol / L potassium hydroxide solution and placed in a negative pressure environment of -0.1 MPa for 14 d. The tab was first fixed to the electrode, and then the cement-based separator soaked in the electrolyte was placed between the positive and negative electrodes, and a sandwich structure was formed by fixing with adhesive tape. Finally, the supercapacitor was sealed and tested for alternating current impedance spectrum under the condition of a test frequency range of 0.1-10 6 Hz, Figure 15 ; the constant current charge and discharge performance and cycle performance of the supercapacitor were tested under the condition of a voltage window of 0-1.0 V and a current density of 0.4 mA / cm 2 , Figure 15 and Figure 15 . According to Figure 15 , the ionic conductivity of the cement-based separator was calculated to be 2.58 S / m. According toFigure 15 , with a maximum specific capacity of 20.7 mWh / g and a 15% energy attenuation after 1400 cycles.

[0147] Example 15

[0148] The cement-based separator of this example was prepared in the same way as that of Example 13, with a slight difference in the porosity of the cement-based separator due to the different experimental batches.

[0149] The energy storage device of this example was prepared in the same way as that of Example 13, with the difference that graphene electrodes were used as the positive and negative electrodes, and the cement-based separator was soaked in a potassium hydroxide solution to form a supercapacitor.

[0150] Cement-based separator preparation: Deionized water and Portland cement were mixed in a ratio of water to cement of 0.5 in a stirring pot for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 d and demolding, the specimen was cured in a curing room at a temperature of 20 ± 2 °C and a relative humidity of more than 95% for 28 d. The specimen was ground into a 1 mm thick sheet and soaked in deionized water for 1 d, then placed in a 4 mol / L ammonium chloride solution. Every 30 min, the mass of the specimen was measured and the mass loss was calculated until the mass loss of the specimen reached 24%. Finally, the cement-based separator was dried in a vacuum drying oven at 45 °C for 7 d, and the porosity of the cement-based separator was 60.85%.

[0151] Graphene electrode preparation: 400 mg of graphene, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 min. 2000 μL of N-methyl pyrrolidone was added to the mortar, and the slurry was quickly stirred to obtain a paste. The paste was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), and then dried in a 60 °C air-drying oven for 24 h. The graphene electrode was cut into a diameter of 12 mm using a tablet press, and the active carbon loading was about 1.63 mg / cm 2 .

[0152] Energy storage device: The graphene electrode was used as the positive and negative electrode, and the cement-based separator was soaked in a potassium hydroxide solution to form a supercapacitor. The dried cement-based separator was immersed in a 6 mol / L potassium hydroxide solution and placed in a negative pressure environment of -0.1 MPa for 14 d. First, the tab was fixed to the electrode, then the cement-based separator soaked with electrolyte was placed between the positive and negative electrodes, and the sandwich structure was fixed with adhesive tape to form a seal. Finally, the alternating current impedance spectrum was tested under the condition of a test frequency range of 0.1-10 6 Hz, Figure 16 ; the constant current charge and discharge performance and cycle performance of the supercapacitor were tested under the condition of a voltage window of 0-1.0 V and a current density of 0.4 mA / cm 2 , Figure 16 and Figure 16 . According to Figure 16, the calculated ionic conductivity of the cement-based separator is 3.48 S / m. According to Figure 16 , the maximum specific capacity is 13.1 mWh / g, and the energy attenuation is 10% after 300 cycles.

[0153] Example 16

[0154] The difference between this example and the cement-based separator of Example 1 is that the cement-based separator is cured for 28 days, and the acid etching solution is 4 mol / L ammonium chloride solution, and the mass loss of the test piece is 28%. The energy storage device of this example is the same as that of Example 1.

[0155] Cement-based separator preparation: Deionized water and Portland cement are mixed in a ratio of water-cement ratio 0.5 in a stirring pot for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm, demolded after hardening for 1 d, and cured in a curing room at a temperature of 20±2℃ and a relative humidity of more than 95% for 28 d. The test piece is polished to a thickness of 1 mm, immersed in deionized water for 1 d, and then placed in a 4 mol / L ammonium chloride solution. Its mass is measured every 30 min and the mass loss is calculated until the mass loss of the test piece reaches 28%. Finally, the cement-based separator is dried in a vacuum drying oven at 45℃ for 7 d, and the porosity is 68.1%.

[0156] Zinc electrode preparation: The zinc foil is cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0157] Graphene electrode preparation: 400 mg of graphene, 50 mg of acetylene black, and 50 mg of polyvinylidene fluoride are placed in a mortar and ground for 10 min. 2000 μL of N-methyl pyrrolidone is added to the mortar, and the slurry is quickly stirred to obtain a slurry. The slurry is evenly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), and then placed in a 60℃ air-drying oven for 24 h. The graphene electrode is cut into a diameter of 12 mm using a tablet press, and the active carbon loading is about 1.63 mg / cm 2 .

[0158] Energy storage device: The graphene electrode is used as the positive electrode, the zinc foil is used as the negative electrode, and the cement-based separator is immersed in zinc sulfate solution to form a supercapacitor. The dried cement-based separator is immersed in 2 mol / L zinc sulfate solution and placed in a negative pressure environment of -0.1 Mpa for 14 d. First, the tab is connected to the electrode, then the cement-based separator soaked with electrolyte is placed between the positive and negative electrodes, and the tape is fixed to form a sandwich structure, and then sealed. Finally, the alternating current impedance spectrum is tested under the condition of test frequency range 0.1-10 6 Hz, see Figure 17 ; the voltage window is 0.2-1.8 V, and the current density is 0.32 mA / cm 2The constant current charge-discharge performance and cycle performance of the hybrid capacitor were tested under the conditions of 0.1 C, 0.5 C, 1 C, 2 C, 5 C and 10 C. The calculated ionic conductivity of the cement-based separator was 0.63 S / m. The maximum specific capacity was 50.5 mWh / g, and the energy attenuation was 16% after 880 cycles.

[0159] Example 17

[0160] The cement-based separator of this example was prepared by the same steps as in Example 16, and the porosity of the obtained cement-based separator was slightly different, which was caused by different experimental batches.

[0161] The difference between the energy storage device of this example and that of Example 16 is that the manganese dioxide electrode is used as the positive electrode, the zinc foil is used as the negative electrode, and the cement-based separator is soaked in a mixed solution of zinc sulfate and manganese sulfate to form a battery.

[0162] Cement-based separator preparation: Deionized water and Portland cement were mixed in a ratio of water-cement ratio 0.5 in a stirring pot for 60 s, then poured into a mold with an inner diameter of 13 mm and a depth of 5 mm. After hardening for 1 d, the mold was removed and placed in a curing room with a temperature of 20±2℃ and a relative humidity of more than 95% for 28 d. The test piece was polished to a thickness of 1 mm and immersed in deionized water for 1 d, then placed in a 4 mol / L ammonium chloride solution. Every 30 min, the mass of the test piece was measured and the mass loss was calculated until the mass loss of the test piece reached 28%. Finally, the cement-based separator was dried in a vacuum drying oven at 45℃ for 7 d, and the porosity of the cement-based separator was 69%.

[0163] Zinc electrode preparation: The zinc foil was cut into a zinc electrode with a diameter of 12 mm using a tablet press.

[0164] Manganese dioxide positive electrode preparation: 350 mg of manganese dioxide, 100 mg of acetylene black and 50 mg of polyvinylidene fluoride were ground in a mortar for 10 min. 1700 μL of N-methyl pyrrolidone was added to the mortar, and the slurry was quickly stirred to obtain a slurry. The slurry was uniformly coated on a 200-mesh stainless steel mesh using a film applicator (10 μm), and then placed in a 60℃ air-drying oven for 24 h. The manganese dioxide positive electrode was cut into a diameter of 12 mm using a tablet press, and the active carbon loading was about 1.05 mg / cm 2 .

[0165] Energy storage device: The manganese dioxide electrode was used as the positive electrode, the zinc foil was used as the negative electrode, and the cement-based separator was soaked in a mixed solution of zinc sulfate and manganese sulfate to form a battery. The dried cement-based separator was immersed in a mixed solution of 2 mol / L zinc sulfate and 0.1 mol / L manganese sulfate, and placed in a negative pressure environment of -0.1 Mpa for 14 d. First, the tab was connected to the electrode, then the cement-based separator soaked with electrolyte was placed between the positive and negative electrodes, and the sandwich structure was fixed with adhesive tape to form a seal. Finally, the test frequency range was 0.1-10 6The AC impedance spectra were tested under the condition of 10 mHz-100 kHz, see Figure 18 The galvanostatic charge-discharge performance and cycle performance of the battery were tested under the condition of voltage window 0.8-1.9 V, current density 0.91 mA / cm 2 The calculated ionic conductivity of the cement-based separator was 0.91 S / m. The maximum specific capacity was 102.4 mWh / g, and the energy attenuation was 6% after 1690 cycles.

Claims

1. A cement-based diaphragm, characterized in that, The cement-based diaphragm has several etched pores distributed on it. These etched pores are obtained by etching away the components of the cement paste sheet with an acidic solution, resulting in a mass loss of 5-40% for the cement paste sheet. The etching process further increases the porosity, pore size, and pore connectivity of the cement paste sheet. The preparation method of the cement-based diaphragm involves first immersing the cement paste sheet in water and placing it in a negative pressure environment to fully saturate it with water. Then, the saturated cement paste sheet is immersed in an acidic solution to etch away the components of the cement paste. The mass loss of the cement paste sheet is monitored. The etched cement paste sheet is then immersed in water to remove the etching solution and subsequently dried to obtain the cement-based diaphragm. The saturation time is 1-3 days, and the negative pressure is -0.05 to -0.1 MPa. The water-cement ratio of the cement paste sheet is 0.3-0.

7.

2. The cement-based diaphragm according to claim 1, characterized in that, The acidic solution is any one or a mixture of several of the following: 1-5 mol / L ammonium chloride solution, 1-6 mol / L ammonium nitrate solution, or 0.1-1 mol / L hydrochloric acid solution.

3. The cement-based diaphragm according to claim 1, characterized in that, The components of the etched cement paste film include one or more of the following: calcium silicate hydrate, calcium hydroxide, calcium carbonate, and ettringite.

4. A method for preparing the cement-based diaphragm according to claim 1, characterized in that, First, cement paste sheets are soaked in water and placed in a negative pressure environment to fully saturate them. Then, the saturated cement paste sheets are soaked in an acidic solution to etch away the components of the cement paste. The mass loss of the cement paste sheets is monitored. The etched cement paste sheets are then soaked in water to remove the etching solution and subsequently dried to obtain the cement-based membrane. The full saturation is achieved by soaking the sheets in water for 1 to 3 days, and the negative pressure is -0.05 to -0.1 MPa. The water-cement ratio for preparing the cement paste sheets is 0.3 to 0.

7.

5. The method for preparing the cement-based diaphragm according to claim 4, characterized in that, The cement paste sheet after etching is soaked in water for 1 to 7 days; the drying is one or more of the following: natural drying, vacuum drying, freeze drying or microwave drying, and the drying time is 1 to 14 days.

6. An electrochemical energy storage device, characterized in that, The electrochemical energy storage device includes a cement-based diaphragm as described in any one of claims 1-3, two tabs, a positive electrode and a negative electrode, wherein the tabs are fixedly connected to the positive and negative electrodes respectively, and the cement-based diaphragm is immersed in electrolyte under negative pressure and placed between the positive and negative electrodes to form a sandwich structure.

7. The electrochemical energy storage device according to claim 6, characterized in that, The positive and negative electrodes are made of metal foil or active material.

8. The electrochemical energy storage device according to claim 7, characterized in that, The method for manufacturing the electrode made of the active material is as follows: first, the active material, conductive agent and binder are put into a mortar and ground evenly. Then, N-methylpyrrolidone is added and stirred rapidly. Finally, the slurry is evenly coated on a conductive carrier and dried to obtain the active material electrode.

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