Coal gangue geopolymer composite solid electrolyte membrane, preparation method and application thereof, and sodium ion battery

Abstract

The application discloses a coal gangue geopolymer composite solid electrolyte film and a preparation method and application thereof and a sodium ion battery, and belongs to the technical field of sodium ion batteries. Raw materials of the coal gangue geopolymer composite solid electrolyte film include a polymer, a sodium salt and a coal gangue geopolymer powder. The preparation method comprises the following steps: uniformly dispersing the polymer and the sodium salt in a solvent, then adding the coal gangue geopolymer powder, and then sequentially performing stirring and ultrasonic treatment to obtain a mixed solution; pouring the mixed solution into a mold, and performing vacuum drying to obtain the coal gangue geopolymer composite solid electrolyte film. The application of the coal gangue geopolymer composite solid electrolyte film in a sodium ion battery. The coal gangue geopolymer composite solid electrolyte film has high ionic conductivity, good electrochemical stability and excellent mechanical performance. The sodium ion battery containing the coal gangue geopolymer composite solid electrolyte film has good cycle performance and excellent rate performance.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery technology, specifically relating to a coal gangue geopolymer composite solid electrolyte membrane, its preparation method and application, and sodium-ion batteries. Background Technology

[0002] With severe environmental pollution, new energy sources have received widespread attention. Sodium, being abundant and inexpensive, is a powerful complement to lithium-ion batteries. Solid-state sodium-ion batteries, which use solid electrolyte membranes to replace the electrolyte and separators of traditional sodium-ion batteries, are gaining increasing attention due to their high safety.

[0003] Composite solid electrolyte membranes combine polymers and inorganic functional fillers; however, commonly used inorganic functional fillers (such as Al2O3 and SiO2) are expensive. Therefore, developing a low-cost inorganic functional filler for use in composite solid electrolyte membranes is an urgent problem to be solved. Summary of the Invention

[0004] To address the problems mentioned in the background section, the present invention aims to provide a coal gangue geopolymer composite solid electrolyte membrane, its preparation method, its application, and a sodium-ion battery. This invention achieves high-value utilization of coal gangue at a low cost, and the coal gangue geopolymer powder prepared from coal gangue is suitable for use in sodium-ion solid electrolyte membranes.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a coal gangue geological polymer composite solid electrolyte membrane, wherein the raw materials of the coal gangue geological polymer composite solid electrolyte membrane include: polymer, sodium salt and inorganic functional filler; The inorganic functional filler is coal gangue geopolymer powder.

[0006] Furthermore, the polymer is selected from one or more of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA).

[0007] Furthermore, the sodium salt is selected from one or more of sodium hexafluorophosphate (NaPF6), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium perchlorate (NaClO4), sodium bis(fluorosulfonyl)imide (NaFSI), and sodium tetrafluoroborate (NaBF4).

[0008] PVDF-HFP is the preferred choice due to its high dielectric constant and mechanical properties, while NaTFSI is the preferred choice due to its large anion, which facilitates dissociation.

[0009] Furthermore, the mass of the inorganic functional filler is 3% of the total mass of the polymer and sodium salt; The mass ratio of the polymer to the sodium salt is 1:0.9.

[0010] Furthermore, the preparation method of the coal gangue geopolymer powder includes the following steps: The coal gangue is crushed and screened to obtain fine-particle coal gangue; The fine-particle coal gangue is calcined to obtain activated coal gangue; Sodium hydroxide solution and sodium silicate solution are mixed and allowed to stand to obtain an alkaline activator; The activated coal gangue and alkali activator are mixed and then pre-cured to obtain a coal gangue geopolymer. The coal gangue geopolymer is coarsely ground and then repeatedly washed until the pH of the washing solution is 7-8. After drying and grinding, the coal gangue geopolymer powder is obtained.

[0011] Furthermore, the fine-grained coal gangue has a mesh size of 200 mesh; And / or, the calcination temperature is 600-800℃, for example, 600℃, 700℃, 800℃, and the calcination time is 2 hours; And / or, the mass ratio of the sodium silicate solution to the sodium hydroxide solution is 0.24:1, the concentration of the sodium hydroxide solution is 5 mol / L, the modulus of the sodium silicate solution is 3.2, and the solid content is 38%; And / or, the settling time is 12-24 hours; And / or, the mass ratio of the activated coal gangue to the alkaline activator is 1:10; And / or, the pre-curing temperature is 70-80℃, and the pre-curing time is 20-24h; And / or, the drying temperature is 70-80℃, and the drying time is 12-14h; And / or, the coal gangue geopolymer powder has a mesh size of 200 mesh.

[0012] On the other hand, the present invention provides a method for preparing the coal gangue geopolymer composite solid electrolyte membrane as described above, comprising the following steps: (1) The polymer and sodium salt are uniformly dispersed in a solvent, then coal gangue geopolymer powder is added, and then the mixture is stirred and ultrasonically treated until the coal gangue geopolymer powder is uniformly distributed in the solution to obtain a mixed solution; (2) The mixed solution is poured into a mold and vacuum dried to obtain the coal gangue geopolymer composite solid electrolyte membrane.

[0013] Further, the solvent is one or more selected from N-dimethylformamide (DMF), acetone (AC), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO); And / or, the stirring temperature is 60°C, the stirring time is 12 hours, and the stirring speed is 240-260 rpm; And / or, the frequency of the ultrasound is 40KHz, the power of the ultrasound is 200W, and the duration of the ultrasound is 1h; And / or, the vacuum drying temperature is 70-80℃, and the vacuum drying time is 20-24h.

[0014] Furthermore, the mold is disc-shaped with a cylindrical cavity inside to hold the mixed solution.

[0015] Furthermore, the mold is made of polytetrafluoroethylene.

[0016] On the other hand, the present invention provides an application of the coal gangue geopolymer composite solid electrolyte membrane described above or the coal gangue geopolymer composite solid electrolyte membrane prepared by any of the above preparation methods in a sodium-ion battery.

[0017] In another aspect, the present invention provides a sodium-ion battery comprising the coal gangue geopolymer composite solid electrolyte membrane described above or the coal gangue geopolymer composite solid electrolyte membrane prepared by any of the preparation methods described above.

[0018] In application, sodium-ion batteries are assembled in the following order: positive electrode shell, positive electrode plate, coal gangue geopolymer composite solid electrolyte membrane, sodium plate, steel plate, spring plate, and negative electrode shell.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Coal gangue is considered difficult to use directly as a high-performance filler due to its low activity and complex composition. This invention successfully transforms coal gangue into a high-efficiency filler with a specific structure (three-dimensional amorphous network) and function (abundant hydroxyl / oxygen vacancies) by using a specific process of "calcination + alkali activation" to form "geopolymer". This realizes the high-value utilization of coal gangue solid waste, turning waste into treasure, with significant environmental benefits, and solves the problem of high cost of existing inorganic functional fillers.

[0020] (2) The coal gangue geopolymer powder used in this invention has a wide range of raw material sources, low cost, simple preparation process, and is easy to scale up production.

[0021] (3) Compared with the preparation of geopolymers in the traditional building materials field, the use of geopolymers in solid electrolyte membranes usually does not require high-energy-consuming processes such as high-temperature sintering, further reducing carbon emissions and energy consumption. Combining coal gangue utilization with batteries is conducive to the vigorous development of new energy sources.

[0022] (4) This invention uses coal gangue geopolymer powder for the preparation of solid electrolyte membranes, which has a unique amorphous structure and more abundant hydroxyl (OH) groups on the surface. - This results in more favorable interfacial interactions, which facilitates the dissociation of sodium salts. Coal gangue geopolymers themselves possess high mechanical strength; using them as inorganic functional fillers in polymer composites significantly improves the mechanical properties of solid electrolyte membranes, achieving simultaneous enhancement of both mechanical and electrochemical properties compared to traditional solid electrolyte membranes.

[0023] (5) The coal gangue geopolymer composite solid electrolyte membrane of the present invention has high ionic conductivity, good electrochemical stability, and excellent mechanical properties. Sodium-ion batteries containing the coal gangue geopolymer composite solid electrolyte membrane have good cycle performance and excellent rate performance. Attached Figure Description

[0024] Figure 1 The images show the XRD patterns of activated coal gangue and uncalcined coal gangue prepared in Examples 1-3 of this invention. Figure 2 The image shows the XRD pattern of the coal gangue geopolymer powder prepared in Example 3 of this invention. Figure 3 The XRD patterns are of the solid electrolyte membranes prepared in Example 4 and Comparative Example 3 of this invention. Figure 4 The impedance diagrams at room temperature are shown for the solid electrolyte membranes prepared in Example 4 and Comparative Examples 1-3 of this invention with a thickness of 0.022 cm. Figure 5 The impedance diagrams at room temperature are for the solid electrolyte membranes prepared in Example 4 and Comparative Examples 1-3 of the present invention with a thickness of 0.02 cm. Figure 6 Linear scanning voltammetry curves of the solid electrolyte membranes prepared in Example 4 and Comparative Example 3 of this invention; Figure 7 The graph shows the rate performance results of the sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 and the sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3. Figure 8 The graph shows the cycle performance results of the sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 of this invention. Figure 9The graph shows the cycle performance results of the sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3 according to the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0026] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0027] Example 1 Preparation of coal gangue geopolymer powder: Coal gangue was crushed and sieved to obtain 200-mesh fine coal gangue particles; the 200-mesh fine coal gangue particles were calcined in a crucible at 600℃ for 2 hours to obtain activated coal gangue; sodium hydroxide solution (5 mol / L) and sodium silicate solution (modulus 3.2, solid content 38%) were mixed (mass ratio of sodium silicate solution to sodium hydroxide solution 0.24:1) and allowed to stand for 12 hours to obtain an alkali activator; the activated coal gangue and alkali activator were mixed (mass ratio of activated coal gangue to alkali activator 1:10) and then pre-cured at 80℃ for 24 hours to obtain coal gangue geopolymer; the coal gangue geopolymer was coarsely ground and then repeatedly washed until the pH of the washing solution was 7, then dried at 80℃ for 12 hours, and then ground to obtain 200-mesh coal gangue geopolymer powder.

[0028] Example 2 Preparation of coal gangue geopolymer powder: Coal gangue was crushed and sieved to obtain 200-mesh fine coal gangue particles; the 200-mesh fine coal gangue particles were calcined in a crucible at 700℃ for 2 hours to obtain activated coal gangue; sodium hydroxide solution (5 mol / L) and sodium silicate solution (modulus 3.2, solid content 38%) were mixed (mass ratio of sodium silicate solution to sodium hydroxide solution 0.24:1) and allowed to stand for 12 hours to obtain an alkali activator; the activated coal gangue and alkali activator were mixed (mass ratio of activated coal gangue to alkali activator 1:10) and then pre-cured at 80℃ for 24 hours to obtain coal gangue geopolymer; the coal gangue geopolymer was coarsely ground and then repeatedly washed until the pH of the washing solution was 7, then dried at 80℃ for 12 hours, and then ground to obtain 200-mesh coal gangue geopolymer powder.

[0029] Example 3 Preparation of coal gangue geopolymer powder: Coal gangue was crushed and sieved to obtain 200-mesh fine coal gangue particles; the 200-mesh fine coal gangue particles were calcined in a crucible at 800℃ for 2 hours to obtain activated coal gangue; sodium hydroxide solution (5 mol / L) and sodium silicate solution (modulus 3.2, solid content 38%) were mixed (mass ratio of sodium silicate solution to sodium hydroxide solution 0.24:1) and allowed to stand for 12 hours to obtain an alkali activator; the activated coal gangue and alkali activator were mixed (mass ratio of activated coal gangue to alkali activator 1:10) and then pre-cured at 80℃ for 24 hours to obtain coal gangue geopolymer; the coal gangue geopolymer was coarsely ground, then repeatedly washed with water by vacuum filtration until the pH of the filtrate was 7, then dried at 80℃ for 12 hours, and then ground to obtain 200-mesh coal gangue geopolymer powder.

[0030] Example 4 The raw materials for the coal gangue geopolymer composite solid electrolyte membrane include: PVDF-HFP, NaTFSI, and the coal gangue geopolymer powder prepared in Example 3.

[0031] Preparation of coal gangue geopolymer composite solid electrolyte membrane: (1) Mix PVDF-HFP (1g), NaTFSI (0.9g) and DMF (8mL), stir at 60℃ for 12h, and after uniform dispersion, add 3% of coal gangue geopolymer powder of total mass of PVDF-HFP and NaTFSI, and stir at 240rpm and 60℃ for 12h. Then sonicate at 40KHz and 200W for 1h to obtain a mixed solution; (2) Cast the mixed solution prepared in step (1) into a custom mold using the solution casting method, and dry in a vacuum drying oven at 80℃ for 24h to obtain a coal gangue geopolymer composite solid electrolyte membrane. The custom mold is disc-shaped with a cylindrical cavity inside to hold the mixed solution. The material of the custom mold is polytetrafluoroethylene.

[0032] Comparative Example 1 The raw materials for the coal gangue geopolymer composite solid electrolyte membrane include: PVDF-HFP, NaTFSI, and the coal gangue geopolymer powder prepared in Example 3.

[0033] Preparation of coal gangue geopolymer composite solid electrolyte membrane: (1) Mix PVDF-HFP (1g), NaTFSI (0.9g) and DMF (8mL), stir at 60℃ for 12h, and after uniform dispersion, add 5% of coal gangue geopolymer powder of total mass of PVDF-HFP and NaTFSI, and stir at 240rpm and 60℃ for 12h. Then sonicate at 40KHz and 200W for 1h to obtain a mixed solution; (2) Use solution casting method to cast the mixed solution prepared in step (1) into a custom mold, and dry in a vacuum drying oven at 80℃ for 24h to obtain a coal gangue geopolymer composite solid electrolyte membrane. The custom mold is disc-shaped with a cylindrical cavity inside to hold the mixed solution. The material of the custom mold is polytetrafluoroethylene.

[0034] Comparative Example 2 The raw materials for the coal gangue geopolymer composite solid electrolyte membrane include: PVDF-HFP, NaTFSI, and the coal gangue geopolymer powder prepared in Example 3.

[0035] Preparation of coal gangue geopolymer composite solid electrolyte membrane: (1) Mix PVDF-HFP (1g), NaTFSI (0.9g) and DMF (8mL), stir at 60℃ for 12h, and after uniform dispersion, add 7% of coal gangue geopolymer powder of total mass of PVDF-HFP and NaTFSI, and stir at 240rpm and 60℃ for 12h. Then sonicate at 40KHz and 200W for 1h to obtain a mixed solution; (2) Use solution casting method to cast the mixed solution prepared in step (1) into a custom mold, and dry in a vacuum drying oven at 80℃ for 24h to obtain a coal gangue geopolymer composite solid electrolyte membrane. The custom mold is disc-shaped with a cylindrical cavity inside to hold the mixed solution. The material of the custom mold is polytetrafluoroethylene.

[0036] Comparative Example 3 The raw materials for solid electrolyte membranes include: PVDF-HFP and NaTFSI.

[0037] Preparation of solid electrolyte membrane: (1) Mix PVDF-HFP (1g), NaTFSI (0.9g) and DMF (8mL), stir at 60℃ for 12h, and obtain a mixed solution after uniform dispersion; (2) Use solution casting method to cast the mixed solution prepared in step (1) into a custom mold, and dry in a vacuum drying oven at 80℃ for 24h to obtain a solid electrolyte membrane. The custom mold is disc-shaped with a cylindrical cavity inside to hold the mixed solution. The material of the custom mold is polytetrafluoroethylene.

[0038] XRD tests were performed on the activated coal gangue and uncalcined coal gangue prepared in Examples 1-3, and the results are as follows: Figure 1 As shown. From Figure 1 As can be seen, in uncalcined coal gangue, kaolinite loses its water of crystallization upon heating, its crystal structure is destroyed, and it transforms into amorphous metakaolinite. The hematite phase also disappears, resulting in a calcined product rich in amorphous active aluminosilicates. XRD analysis was performed on the coal gangue geopolymer powder prepared in Example 3, and the results are as follows... Figure 2 As shown. From Figure 2 As can be seen, the coal gangue after alkali activation exhibited broad and diffuse peaks, successfully forming a geopolymer material with an amorphous gel as a continuous matrix. XRD tests were performed on the solid electrolyte membranes prepared in Example 4 and Comparative Example 3, and the results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the addition of coal gangue geopolymer powder significantly reduces the crystallinity of the polymer and increases the amorphous regions.

[0039] The ionic conductivity of the solid electrolyte membranes prepared in Example 4 and Comparative Examples 1-3 was tested using AC impedance spectroscopy. During AC impedance spectroscopy testing, the solid electrolyte membranes were assembled into a stainless steel || solid electrolyte membrane || stainless steel symmetrical blocking cell, with parameters set as follows: amplitude 10mV, frequency 0.01~106Hz. σ represents the ionic conductivity of the solid electrolyte membrane. The ionic conductivity can be calculated using the formula σ=L / (R×S). Substituting the measured ohmic impedance value of the solid electrolyte membrane into the formula yields the ionic conductivity under different conditions. Where L is the thickness of the solid electrolyte membrane, S is the effective contact area between the stainless steel and the solid electrolyte membrane, and R is the ohmic impedance value of the solid electrolyte membrane measured by AC impedance spectroscopy. The impedance diagrams of the solid electrolyte membranes prepared in Example 4 and Comparative Examples 1-3 are shown below. Figure 4 and Figure 5 As shown in Table 1, the ionic conductivity results are as follows.

[0040] Table 1. Ionic conductivity results of solid electrolyte membranes prepared in Example 4 and Comparative Examples 1-3

[0041] from Figure 4 , Figure 5 As can be seen from Table 1, compared to the solid electrolyte membrane prepared in Comparative Example 3, the ionic conductivity of the solid electrolyte membrane prepared in Example 4 of this invention is 3.22 × 10⁻⁶ at a thickness of 0.022 cm. -4 (S / cm) increased to 7.26×10 -4 (S / cm), at a thickness of 0.02cm, it is 3.62×10 -4(S / cm) increased to 5.56×10 -4 (S / cm), while the ionic conductivity of the solid electrolyte membranes prepared in Comparative Examples 1 and 2 decreased. This is because the addition of inorganic functional fillers can disrupt the regular arrangement of polymer chains, increasing the proportion of amorphous regions in the polymer that are conducive to ion conduction, thus providing Na+. + The transition provides more pathways; at the same time, the abundant active sites on its surface generate more favorable interfacial interactions, which helps sodium salt dissociation. However, as the content of inorganic functional fillers increases, inorganic particles aggregate to form insulating agglomerates, which block ion conduction pathways, disrupt the continuous polymer phase, and lead to a significant increase in interfacial impedance and a decrease in ionic conductivity.

[0042] The solid electrolyte membranes prepared in Example 4 and Comparative Example 3 were analyzed for their stable electrochemical window using linear sweep voltammetry (LSV). A three-electrode system was used to test a sodium metal sheet (Na)||solid electrolyte membrane||stainless steel (SS) half-cell. The test parameters were: voltage range 2–6 V, scan rate 1 mV / s, and temperature 300 K. The test results are as follows: Figure 6 As shown. From Figure 6 As can be seen, the solid electrolyte membrane prepared in Comparative Example 3 showed a significant current at around 3.9V, while the solid electrolyte membrane prepared in Example 4 only started to show a significant current at around 4.5V, indicating that the solid electrolyte membrane with added coal gangue geopolymer powder has better electrochemical stability.

[0043] The solid electrolyte membranes prepared in Example 4 and Comparative Example 3 were subjected to mechanical property tests. The mechanical properties of the solid electrolyte membranes were tested using a universal tensile testing machine. Tensile strength is the ratio of the maximum load that the test sample can withstand to the original cross-sectional area of ​​the sample, expressed by the formula P = F / S, where P is the tensile strength, F is the maximum load that the test sample can withstand, and S is the original cross-sectional area of ​​the test sample. The equipment used for the tensile test of the solid electrolyte membrane in this invention was a CMT7504 universal testing machine, and the test parameters were as follows: tensile speed was 10 mm / min. -1 The sample size was 40mm × 15mm. The test results are shown in Table 2.

[0044] Table 2. Mechanical properties of the solid electrolyte membranes prepared in Example 4 and Comparative Example 3.

[0045] As can be seen from Table 2, the addition of coal gangue geopolymer powder improved the tensile strength of the solid electrolyte membrane, indicating an increase in mechanical strength. At the same time, the increase in elongation at break indicates an improvement in elastic properties.

[0046] Sodium vanadium phosphate (a positive electrode active material), acetylene black (a conductive agent), and polyvinylidene fluoride (PVDF) (a binder) were mixed with N-methylpyrrolidone (NMP) (an organic solvent) at a mass ratio of 7:2:1 to obtain a positive electrode slurry. The positive electrode slurry was then coated onto aluminum foil using a coating machine and dried at 80°C for 24 hours to obtain a positive electrode sheet.

[0047] Sodium-ion batteries are assembled in the following order: positive electrode shell, positive electrode sheet, solid electrolyte membrane prepared in Example 4, sodium sheet, steel sheet, spring sheet, and negative electrode shell, to obtain a sodium-ion battery containing the solid electrolyte membrane prepared in Example 4.

[0048] Sodium-ion batteries are assembled in the following order: positive electrode shell, positive electrode sheet, solid electrolyte membrane prepared in Comparative Example 3, sodium sheet, steel sheet, spring sheet, and negative electrode shell, to obtain a sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3.

[0049] Rate performance tests were performed on a sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 and a sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3. The results are as follows: Figure 7 As shown. From Figure 7 As can be seen, compared to the sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3, the sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 shows a certain improvement in discharge capacity at all rates. In particular, at 2C rate, the sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3 almost decays to 0 in discharge specific capacity, while the sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 still has a discharge specific capacity greater than 50 mAh•g. -1 The specific discharge capacity.

[0050] Cycle performance tests were performed on a sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 and a sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3. The results are as follows: Figure 8 and Figure 9 As shown. From Figure 8 and Figure 9 As can be seen from the data, the sodium-ion battery containing the solid electrolyte membrane prepared in Comparative Example 3 has a power output of 66.1 mAh•g at 0.5C. -1 The initial discharge specific capacity; the discharge specific capacity after 150 cycles is 64.1 mAh•g. -1 The capacity retention rate was 97%; the discharge specific capacity after 300 cycles was 57.4 mAh·g. -1 The capacity retention rate was 86.8%. The sodium-ion battery containing the solid electrolyte membrane prepared in Example 4 had a capacity of 89.8 mAh•g at 0.5C. -1 The initial discharge specific capacity; the discharge specific capacity after 150 cycles is 87.2 mAh•g. -1The capacity retention rate was 97.1%; the discharge specific capacity after 300 cycles was 86.4 mAh•g. -1 The capacity retention rate was 96.2%.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A coal gangue geopolymer composite solid electrolyte membrane, characterized in that, The raw materials for the coal gangue geopolymer composite solid electrolyte membrane include: polymer, sodium salt and inorganic functional filler; The inorganic functional filler is coal gangue geopolymer powder; The inorganic functional filler has a mass of 3% of the total mass of the polymer and sodium salt; The mass ratio of the polymer to the sodium salt is 1:0.9; The preparation method of the coal gangue geopolymer powder includes the following steps: The coal gangue is crushed and screened to obtain fine-particle coal gangue; The fine-particle coal gangue is calcined to obtain activated coal gangue; Sodium hydroxide solution and sodium silicate solution are mixed and allowed to stand to obtain an alkaline activator; The activated coal gangue and alkali activator are mixed and then pre-cured to obtain a coal gangue geopolymer. The coal gangue geopolymer is coarsely ground and then repeatedly washed until the pH of the washing solution is 7-8. After drying and grinding, the coal gangue geopolymer powder is obtained. The calcination temperature is 600-800℃, and the calcination time is 2 hours; The mass ratio of sodium silicate solution to sodium hydroxide solution is 0.24:1, the concentration of sodium hydroxide solution is 5 mol / L, the modulus of sodium silicate solution is 3.2, and the solid content is 38%. The settling time is 12-24 hours; The mass ratio of the activated coal gangue to the alkaline activator is 1:10; The pre-curing temperature is 70-80℃, and the pre-curing time is 20-24h.

2. The coal gangue geopolymer composite solid electrolyte membrane according to claim 1, characterized in that, The polymer is selected from one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polyacrylonitrile, and polymethyl methacrylate.

3. The coal gangue geopolymer composite solid electrolyte membrane according to claim 1, characterized in that, The sodium salt is selected from one or more of sodium hexafluorophosphate, sodium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium bis(fluorosulfonyl)imide, and sodium tetrafluoroborate.

4. The coal gangue geopolymer composite solid electrolyte membrane according to claim 1, characterized in that, The fine-grained coal gangue has a mesh size of 200 mesh; And / or, the drying temperature is 70-80℃, and the drying time is 12-14h; And / or, the coal gangue geopolymer powder has a mesh size of 200 mesh.

5. The method for preparing the coal gangue geopolymer composite solid electrolyte membrane according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The polymer and sodium salt are uniformly dispersed in a solvent, then coal gangue geopolymer powder is added, and then the mixture is stirred and ultrasonically treated in sequence to obtain a mixed solution; (2) The mixed solution is poured into a mold and vacuum dried to obtain the coal gangue geopolymer composite solid electrolyte membrane.

6. The preparation method according to claim 5, characterized in that, The solvent is one or more of N,N-dimethylformamide, acetone, N-methylpyrrolidone, and dimethyl sulfoxide; And / or, the stirring temperature is 60°C, the stirring time is 12 hours, and the stirring speed is 240-260 rpm; And / or, the frequency of the ultrasound is 40KHz, the power of the ultrasound is 200W, and the duration of the ultrasound is 1h; And / or, the vacuum drying temperature is 70-80℃, and the vacuum drying time is 20-24h.

7. The application of the coal gangue geopolymer composite solid electrolyte membrane according to any one of claims 1-4 or the coal gangue geopolymer composite solid electrolyte membrane prepared by any one of claims 5-6 in sodium-ion batteries.

8. A sodium-ion battery, characterized in that, The coal gangue geopolymer composite solid electrolyte membrane according to any one of claims 1-4 or the coal gangue geopolymer composite solid electrolyte membrane prepared by any one of claims 5-6.

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