Preparation Method and Application of Hexagonal Hole SnO2@Ti3C2 Electrode Material for High-Energy-Density All-Solid-State Supercapacitors

Abstract

Preparation method and application of a hexagonal pore SnO2@Ti3C2 electrode material for a high energy density all-solid-state supercapacitor. Place the Ti3AlC2 precursor powder with hexagonal pores in a mixed solution of SnCl4·5H2O, HCl, and CaF2, and simultaneously perform etching and ion intercalation through a microwave reactor at room temperature. The obtained Sn 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder is mixed with deionized water. Subsequently, SnCl4·5H2O and NaOH are added to the mixed solution, and the mixture is uniformly stirred at room temperature, transferred to the inner lining of a reaction kettle, and the SnO2@Ti3C2 electrode material is prepared by microwave-assisted method through a microwave reactor. The advantages are: the process method is simple, fast, and has good stability. The synthesized SnO2@Ti3C2 can maintain stable performance in different environments, and the pseudocapacitance property brought also further improves the energy density.

Description

Technical Field

[0001] The present invention belongs to the field of all-solid-state supercapacitors for new energy vehicles, and particularly relates to a preparation method and application of a hexagonal pore SnO2@Ti3C2 electrode material for all-solid-state supercapacitors with high energy density. Background Art

[0002] New energy vehicles, with their green and environmental protection characteristics, have become a key force in promoting green travel and reducing carbon emissions. They represent the future development direction of the automotive industry. The popularization and development of new energy vehicles can not only reduce the dependence on fossil fuels, lower greenhouse gas emissions, but also promote the optimization of the energy structure and industrial upgrading.

[0003] As an ideal energy storage device for new energy vehicles, supercapacitors have the advantages of rapid charge and discharge, long cycle life, and high power output, and have broad development prospects. However, traditional supercapacitors often use organic electrolytes to improve the energy density of the capacitors, but the organic electrolytes used often have toxicity and are prone to leakage during use, posing safety hazards to the environment and users. Therefore, it is particularly important to develop safe all-solid-state supercapacitors with high energy density.

[0004] Solid-state supercapacitors significantly improve the safety and stability of energy storage devices for new energy vehicles by using solid electrolytes. The key to performance improvement lies in the optimization of electrode materials. Selecting appropriate electrode materials can greatly enhance the energy density of supercapacitors. Among many electrode materials, two-dimensional layered Ti3C2 has attracted much attention due to its unique properties. As a representative of the MXene series of materials, it has rich surface functional groups, excellent electrical conductivity, and outstanding mechanical flexibility. Limited by the low voltage window, the improvement of its energy density faces bottlenecks. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a preparation method and application of a hexagonal pore SnO2@Ti3C2 electrode material for all-solid-state supercapacitors with high energy density.

[0006] The technical solution of the present invention is as follows:

[0007] A preparation method of a hexagonal pore SnO2@Ti3C2 electrode material for all-solid-state supercapacitors with high energy density, comprising the following steps:

[0008] (1) Prepare Ti3AlC2 precursor powder with hexagonal pores

[0009] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly according to the molar ratio of (5 - 7):1:1. Under the protection of an inert atmosphere, react in a vacuum hot-pressing sintering furnace. After the reaction, introduce liquid nitrogen for cooling, and then grind to 200 mesh to obtain a precursor powder with hexagonal pores;

[0010] (2) Synchronously prepare Sn by microwave-assisted etching and ion intercalation 4+ Add SnCl4·5H2O to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Add the precursor powder with hexagonal pores prepared in step (1), mix evenly, place it in a microwave reactor at room temperature, and perform microwave-assisted etching and ion intercalation. Then, wash with dilute hydrochloric acid with a concentration of 1 mol·L -1 , then ultrasonically treat for 1 h at room temperature, centrifuge, retain the precipitate, wash it with deionized water until the solution pH = 6, vacuum filter, and dry in a vacuum drying oven to obtain Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder;

[0011] (3) Use SnCl4·5H2O as a tin source to synthesize tin dioxide-coated tin ion-intercalated Ti3C2 powder by microwave-assisted synthesis

[0012] In the Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder prepared in step (2) and an aqueous solution of SnCl4·5H2O, add NaOH to adjust the pH value to 12 - 13, stir at room temperature for 20 - 40 min, then place it in the inner lining of the reaction kettle and prepare it by microwave-assisted through a microwave reactor. Wash with deionized water until the pH value is 6 - 7, and dry in a vacuum drying oven to obtain tin dioxide-coated tin ion-intercalated Ti3C2 (SnO2@Ti3C2) powder.

[0013] Furthermore, in step (1), the inert atmosphere is an argon atmosphere; the pressure of the pressing head of the vacuum hot-pressing sintering furnace is set to 20 T, the reaction temperature in the vacuum hot-pressing sintering furnace is 700 °C - 850 °C, and the reaction time is 6 h - 12 h.

[0014] Furthermore, in step (1), introduce liquid nitrogen for cooling, and the cooling time is 1 hour.

[0015] Furthermore, in step (2), in the SnCl4·5H2O-CaF2-HCl mixed solution, the concentration of HCl is 7 mol·L -1 - 9 mol·L -1 , the molar ratio of HCl to CaF2 is 5:4, and the concentration of SnCl4·5H2O is 0.25 mol·L -1, the mass-volume ratio of the precursor powder with hexagonal pores to the SnCl4·5H2O-CaF2-HCl mixed solution is 1:20 g·mL -1 .

[0016] Furthermore, in step (1), the molar ratio of Ti3AlC2 to ZnCl2 and CuCl2 is 5:1:1; in step (2), in the SnCl4·5H2O-CaF2-HCl mixed solution, the concentration of HCl is 9 mol·L -1 , Sn 4+ The Sn-intercalated hexagonal pore Ti3C2 has a hexagonal pore structure, and the hexagonal pores have an obvious layered morphology, which provides more active sites for ion transport and helps to improve the capacitance performance.

[0017] Furthermore, in step (2), during pickling, it is washed with dilute hydrochloric acid with a concentration of 1 mol·L -1 . In step (2), during centrifugation, the centrifugation speed is 3000 rpm to 5000 rpm, and the centrifugation time is 15 min.

[0018] Furthermore, in step (3), the concentration of the SnCl4·5H2O aqueous solution is 0.075 mol·L -1 ~0.15 mol·L -1 , and the mass ratio of Sn 4+ intercalated Ti3C2 to SnCl4·5H2O in the solution is 1:(1-2). Preferably, in step (3), in the SnCl4·5H2O aqueous solution, the mass-volume ratio of SnCl4·5H2O to deionized water is 1:40 g / mL.

[0019] Furthermore, in steps (2) and (3), during microwave-assisted reaction in the microwave reactor, the microwave-assisted power is 300 W, the frequency is 2.45 GHz, the pressure is 2.0 MPa, and the reaction time is 3 h.

[0020] Application of the hexagonal pore SnO2@Ti3C2 electrode material prepared by the above preparation method as a positive electrode material and a negative electrode material in an all-solid-state supercapacitor.

[0021] Application of the hexagonal pore SnO2@Ti3C2 electrode material prepared by the above preparation method in an all-solid-state supercapacitor, characterized in that: the all-solid-state supercapacitor is specifically assembled as follows:

[0022] (1) Preparation of the negative electrode of the high energy density all-solid-state supercapacitor

[0023] Mix the SnO2@Ti3C2 electrode material, acetylene black, and PVDF in a mass ratio of 8.5:1:0.5, add NMP dropwise to form a mixed slurry, evenly coat it on 1 cm × 1 cm nickel foam, roll it flat to form an electrode sheet, and dry it in a vacuum drying oven at 80 °C for 8 hours to obtain the negative electrode material.

[0024] (2) The specific steps for preparing the positive electrode of the high energy density all-solid-state supercapacitor are as follows

[0025] Mix the Sn 4+ Intercalated Ti3C2 electrode material, acetylene black, and PVDF in a mass ratio of 8.5:1:0.5, add NMP dropwise to form a mixed slurry, evenly coat it on 1 cm × 1 cm nickel foam, roll it flat to form an electrode sheet, and dry it in a vacuum drying oven at 80 °C for 8 h to obtain the positive electrode material.

[0026] (3) Preparation of the electrolyte of the high energy density all-solid-state supercapacitor

[0027] Mix Li2S, P2S5, and LiCl in a molar ratio of 4.2:1:2 and grind them, and then sinter them in a vacuum sintering furnace at 500 °C under vacuum for 5 h. After cooling, obtain the solid electrolyte.

[0028] (4) The specific steps for assembling the high energy density all-solid-state supercapacitor are as follows

[0029] Assemble the positive electrode sheet, negative electrode sheet, and solid electrolyte into an all-solid-state supercapacitor.

[0030] The beneficial effects of the present invention are:

[0031] (1) Using Ti3AlC2 as the raw material, ZnCl2 and CuCl2 as defect inducing agents, through vacuum hot pressing sintering method and liquid nitrogen cooling method, it is easy to prepare, the reaction temperature is low, and the obtained unique hexagonal pore structure provides additional adsorption channels for ions, which helps to improve the capacitance performance.

[0032] (2) Sn 4+ The intercalated multi-layer hexagonal pore Ti3C2 material can fully expose the active sites through cation intercalation. The in-situ intercalation method of "etching - intercalation" carried out synchronously can better increase the layer spacing. After cation intercalation, it plays a supporting role and effectively inhibits the phenomenon of close stacking of the sheets.

[0033] (3) A tin ion intercalated Ti3C2 composite material coated with tin dioxide is synthesized by microwave-assisted method, which is characterized by short rod-shaped SnO2 coated Ti3C2. The interaction between SnO2 and Ti3C2 can greatly improve the conductivity and structural stability. At the same time, due to the pseudocapacitance property brought by SnO2, a highly reversible redox reaction occurs on the electrode surface to store charges, thereby improving the energy density of the all-solid-state supercapacitor.

[0034] The preparation method provided by the present invention is simple, fast and has a high yield, which is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 XRD patterns of the precursor with hexagonal pores, Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 and tin ion intercalated Ti3C2 composite material coated with tin dioxide in Example 1 of the present invention;

[0036] Figure 2 XRD pattern of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 in Example 1 of the present invention;

[0037] Figure 3 SEM image of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 in Example 1 of the present invention;

[0038] Figure 4 SEM image of tin ion intercalated Ti3C2 composite material coated with tin dioxide with hexagonal pores in Example 1 of the present invention;

[0039] Figure 5 Magnified SEM image of tin ion intercalated Ti3C2 composite material coated with tin dioxide in Example 1 of the present invention;

[0040] Figure 6 Graph showing the relationship between the specific capacitance of tin ion intercalated Ti3C2 composite material coated with tin dioxide with hexagonal pores and the charge-discharge cycle of the supercapacitor in Example 1 of the present invention;

[0041] Figure 7 Graph showing the relationship between the energy density of tin ion intercalated Ti3C2 composite material coated with tin dioxide with hexagonal pores and the power density of the supercapacitor in Example 1 of the present invention;

[0042] Figure 8 SEM image of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder in Example 2 of the present invention;

[0043] Figure 9 SEM image of Sn4+ Scanning electron microscope image of intercalated multi-layer hexagonal pore Ti3C2 powder;

[0044] Figure 10 is Sn in Comparative Example 1 of the present invention 4+ Scanning electron microscope image of intercalated multi-layer Ti3C2;

[0045] Figure 11 is the scanning electron microscope image of the Sn ion intercalated Ti3C2 powder coated with tin dioxide synthesized directly using SnCl4·5H2O as the tin source in Comparative Example 2 of the present invention;

[0046] Figure 12 is Sn obtained by the non-in-situ intercalation method in Comparative Example 3 of the present invention and the in-situ intercalation method in Example 1 4+ XRD pattern of intercalated multi-layer hexagonal pore Ti3C2 powder. Detailed implementation manners

[0047] Example 1

[0048] (1) Preparation of Ti3AlC2 precursor powder with hexagonal pores

[0049] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly at a molar ratio of 5:1:1. Under the protection of inert gas argon, put them into a vacuum hot-pressing sintering furnace. The power of the vacuum hot-pressing sintering furnace is 65KW, the pressure of the press head is set to 20T, and the diameter of the effective contact surface of the press head is Ф90mm; Use argon as the protective atmosphere in the furnace, the inflation pressure is set to 0.03MPa, react at 700°C for 6 hours, after the reaction, introduce liquid nitrogen for cooling for 1h, and grind to 200 mesh to obtain the precursor powder with hexagonal pores;

[0050] (2) Simultaneously prepare Sn intercalated multi-layer hexagonal pore Ti3C2 powder by microwave-assisted etching and ion intercalation 4+ Add SnCl4·5H2O to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Among them, the molar ratio of HCl to CaF2 in the mixed solution is 5:4, and the concentration of HCl is 9mol·L -1 , the concentration of SnCl4·5H2O is 0.25mol·L -1 , put 1g of the precursor powder prepared in step (1) into 20mL of the SnCl4·5H2O-CaF2-HCl mixed solution. In the microwave reactor, the microwave-assisted power is 300W, the frequency is 2.45GHz, the pressure is 2.0MPa, and etching and ion intercalation are carried out simultaneously at room temperature. The reaction time is 3h, and then use a concentration of 1mol·L -1Wash the impurities with dilute hydrochloric acid, then perform ultrasonic treatment for 1 h. Put the suspension obtained after ultrasonic treatment into a centrifuge, with a centrifugation speed of 3000 rpm and a centrifugation time of 15 min. After centrifugation, pour off the supernatant, take out the centrifuged precipitate, and wash it with deionized water until the solution pH = 6. Then perform vacuum filtration and dry it in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder;

[0051] (3) Using SnCl4·5H2O as the tin source, synthesize tin dioxide-coated tin ion intercalated Ti3C2 powder by microwave-assisted method. Dissolve 0.5 g of SnCl4·5H2O in 20 mL of deionized water to obtain an aqueous solution of SnCl4·5H2O. Add 0.5 g of Sn 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder prepared in step (2), then add NaOH to adjust the pH to 12, stir at room temperature for 30 min, and then pour it into the inner lining of the reaction kettle. Under the conditions of a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 MPa, carry out microwave-assisted reaction in a microwave reactor for 3 h. After the reaction is completed, wash it with deionized water until the pH value is 7, perform vacuum filtration, and dry it in a vacuum drying oven at 80 °C for 8 hours to obtain tin dioxide-coated tin ion intercalated Ti3C2 (SnO2@Ti3C2) powder;

[0052] (4) Assembly of all-solid-state supercapacitor

[0053] ① Preparation of negative electrode plate

[0054] Mix tin dioxide-coated tin ion intercalated Ti3C2 powder as the electrode material, acetylene black, and PVDF according to a mass ratio of 8.5:1:0.5, add NMP dropwise to form a mixed slurry, evenly coat it on a 1 cm × 1 cm nickel foam, roll it flat to form an electrode plate, and dry it in a vacuum drying oven at 80 °C for 8 hours to obtain a negative electrode plate;

[0055] ② Preparation of positive electrode plate

[0056] Use Sn 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder as the electrode material, acetylene black, and PVDF according to a mass ratio of 8.5:1:0.5, add NMP dropwise to form a mixed slurry, evenly coat it on a 1 cm × 1 cm nickel foam, roll it flat to form an electrode plate, and dry it in a vacuum drying oven at 80 °C for 8 h to obtain a positive electrode plate; ③ Preparation of solid electrolyte

[0057] Mix Li2S, P2S5, and LiCl according to a molar ratio of 4.2:1:2 and grind them, and then perform vacuum sintering at 500 °C in a vacuum sintering furnace for 5 h. After cooling, obtain a solid electrolyte;

[0058] ④Assembly of all-solid-state supercapacitor

[0059] Assemble the positive electrode sheet in step ②, the negative electrode sheet in step ① and the solid electrolyte in step ③ into an all-solid-state supercapacitor.

[0060] From Figure 1 The shown X-ray diffraction pattern (XRD) indicates that the tin dioxide-coated tin ion intercalated Ti3C2 negative electrode material and Sn 4+ intercalated Ti3C2 positive electrode material are successfully prepared; from Figure 2 and Figure 3 the scanning electron microscope images, it can be seen that the Sn 4+ intercalated hexagonal pore Ti3C2 has a hexagonal pore structure, and the hexagonal pores have an obvious layered morphology, which provides more active sites for ion storage; from Figure 4 the scanning electron microscope image shows that the tin dioxide-coated tin ion intercalated Ti3C2 powder with hexagonal pores is successfully prepared and has an obvious coating morphology; from Figure 5 as shown, through local magnification, it can be seen that short rod-shaped SnO2 is coated on Ti3C2, increasing the specific surface area and improving the electric double layer capacitance. Due to the combination of the pseudocapacitance property of SnO2, the total specific capacitance is increased.

[0061] Example 2

[0062] (1) Preparation of Ti3AlC2 precursor powder with hexagonal pores

[0063] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly according to a molar ratio of 6:1:1. Under the protection of inert gas argon, put it into a vacuum hot press sintering furnace. The power of the vacuum hot press sintering furnace is 65KW, the pressure of the press head is set to 20T, and the diameter of the effective contact surface of the press head is Ф90mm; use argon as the protective atmosphere in the furnace, the inflation pressure is set to 0.03MPa, react at 850°C for 12 hours, after the reaction, introduce liquid nitrogen for cooling for 1h, and grind to 200 meshes to obtain the precursor powder with hexagonal pores;

[0064] (2) Simultaneously prepare Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder by microwave-assisted etching and ion intercalation. Add SnCl4·5H2O to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Among them, the molar ratio of HCl to CaF2 in the mixed solution is 5:4, and the concentration of HCl is 8mol·L -1 , and the concentration of SnCl4·5H2O is 0.25mol·L -1, 1 g of the precursor powder prepared in step (1) was placed in a 20 mL mixed solution of SnCl4·5H2O - CaF2 - HCl. In a microwave reactor, at room temperature, under a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 Mpa, the microwave reactor carried out microwave-assisted reaction, synchronously performing etching and ion intercalation. The reaction time was 3 h, and then impurities were washed away with dilute hydrochloric acid with a concentration of 1 mol·L -1 of, and then ultrasonic treatment was carried out for 1 h. The suspension obtained after ultrasonic treatment was put into a centrifuge, and the centrifugation speed was 4000 rpm. Centrifugation was carried out for 15 min. After centrifugation was completed, the supernatant was poured off, the centrifuged precipitate was taken out and washed with deionized water until the solution pH = 6, vacuum filtration was carried out, and it was dried in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder;

[0065] (3) Using SnCl4·5H2O as a tin source, tin dioxide-coated tin ion-intercalated Ti3C2 powder was synthesized by microwave assistance

[0066] 1 g of SnCl4·5H2O was dissolved in 20 mL of deionized water to obtain an SnCl4·5H2O aqueous solution. 0.5 g of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder prepared in step (2) was added, and then NaOH was added to adjust the pH to 12. Stirring was carried out at room temperature for 30 min, and then it was poured into the inner lining of the reaction kettle. Under a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 MPa, the microwave reactor carried out microwave-assisted reaction for 3 h. After the reaction was completed, it was washed with deionized water until the pH value was 7, vacuum filtration was carried out, and it was dried in a vacuum drying oven at 80 °C for 8 hours to obtain tin dioxide-coated tin ion-intercalated Ti3C2 powder;

[0067] (4) The assembly of the all-solid-state supercapacitor was the same as in Example 1.

[0068] From Figure 8 the scanning electron microscope images shown, compared with Example 1, due to the different molar ratios of Ti3AlC2 to ZnCl2 and CuCl2, the hexagonal pores have not been fully formed, and the hydrochloric acid concentration is relatively low, resulting in an unclear layering effect, which should be the intermediate state of the reaction in Example 1.

[0069] Example 3

[0070] (1) Preparation of Ti3AlC2 precursor powder with hexagonal pores

[0071] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly at a molar ratio of 7:1:1. Under the protection of an inert argon atmosphere, place them in a vacuum hot-pressing sintering furnace. The power of the vacuum hot-pressing sintering furnace is 65 KW, the pressure of the press head is set to 20 T, and the diameter of the effective contact surface of the press head is Ф90 mm. Use argon as the protective atmosphere in the furnace, set the inflation pressure to 0.03 MPa, react at 800 °C for 9 hours, after the reaction, introduce liquid nitrogen for cooling h, grind to 200 mesh to obtain a precursor powder with hexagonal pores;

[0072] (2) Synchronously prepare Sn by microwave-assisted etching and ion intercalation 4+ Add SnCl4·5H2O to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Among them, the molar ratio of HCl to CaF2 in the mixed solution is 5:4, and the concentration of HCl is 7 mol·L -1 , and the concentration of SnCl4·5H2O is 0.25 mol·L -1 . Place 1 g of the precursor powder prepared in step (1) in 20 mL of the SnCl4·5H2O-CaF2-HCl mixed solution. In a microwave reactor, under the conditions of a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 Mpa at room temperature, carry out microwave-assisted reaction in the microwave reactor to synchronously carry out etching and ion intercalation. The reaction time is 3 h, then wash away the impurities with dilute hydrochloric acid with a concentration of 1 mol·L -1 . Then carry out ultrasonic treatment for 1 h. Put the suspension obtained after ultrasonic treatment into a centrifuge, with a centrifugation speed of 5000 rpm and centrifuge for 15 min. After centrifugation, pour off the supernatant, take out the centrifuged precipitate, wash it with deionized water until the solution pH = 6, carry out vacuum filtration, and dry it in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder;

[0073] (3) Use SnCl4·5H2O as the tin source to synthesize tin dioxide-coated tin ion-intercalated Ti3C2 powder by microwave-assisted method. Dissolve 0.75 g of SnCl4·5H2O in 20 mL of deionized water to obtain an SnCl4·5H2O aqueous solution, and add 0.5 g of Sn prepared in step (2) 4+The intercalated multi-layer hexagonal pore Ti3C2 powder was added with NaOH to adjust the pH to 12, stirred at room temperature for 30 min, then poured into the inner lining of the reaction kettle, and under the conditions of a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 MPa, the microwave reactor was used for microwave-assisted reaction for 3 h. After the reaction was completed, it was washed with deionized water until the pH value reached 7, vacuum filtered, and dried in a vacuum drying oven at 80 °C for 8 h to obtain tin ion-intercalated Ti3C2 powder coated with tin dioxide;

[0074] (4) The assembly of the all-solid-state supercapacitor was the same as in Example 1.

[0075] From Figure 9 the SEM images shown, compared with Example 1, due to the different molar ratios of Ti3AlC2 to ZnCl2 and CuCl2, the hexagonal pores have not been completely formed, and the hydrochloric acid concentration is relatively low, resulting in an unclear delamination effect, which should be the intermediate state of the reaction in Example 1.

[0076] Comparative Example 1 In this comparative example, the Ti3AlC2 precursor was not treated by vacuum hot pressing sintering and cooling process

[0077] (1) Synchronously prepare Sn by microwave-assisted etching and ion intercalation 4+ Intercalated multi-layer Ti3C2 powder SnCl4·5H2O was added to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Among them, the molar ratio of HCl to CaF2 in the mixed solution was 5:4, and the concentration of HCl was 9 mol·L -1 , and the concentration of SnCl4·5H2O was 0.25 mol·L -1 . 1 g of Ti3AlC2 powder was placed in 20 mL of the SnCl4·5H2O-CaF2-HCl mixed solution. In the microwave reactor, under the conditions of a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 Mpa, the microwave reactor was used for microwave-assisted reaction to synchronously carry out etching and ion intercalation. The reaction time was 3 h, and then it was washed with dilute hydrochloric acid with a concentration of 1 mol·L -1 to remove impurities, followed by ultrasonic treatment for 1 h. The suspension obtained after ultrasonic treatment was put into a centrifuge, and the centrifugation speed was 3000 rpm. After centrifugation for 15 min, after centrifugation was completed, the supernatant was poured out, the centrifuged precipitate was taken out and washed with deionized water until the solution pH = 6, vacuum filtered, and dried in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ intercalated multi-layer Ti3C2 powder;

[0078] (2) Using SnCl4·5H2O as the tin source, tin ion intercalated Ti3C2 powder coated with tin dioxide was synthesized by microwave-assisted method. Dissolve 0.5 g of SnCl4·5H2O in 20 mL of deionized water to obtain an aqueous solution of SnCl4·5H2O. Add 0.5 g of Sn prepared in step (2) 4+ intercalated multi-layered hexagonal pore Ti3C2 powder, then add NaOH to adjust the pH to 12, stir at room temperature for 30 min, then pour it into the inner lining of the reaction kettle, and under the power of 300 W, the frequency of 2.45 GHz and the pressure of 2.0 MPa, the microwave reactor was used for microwave-assisted reaction for 3 h. After the reaction was completed, it was washed with deionized water until the pH value was 7, vacuum filtered, and dried in a vacuum drying oven at 80 °C for 8 hours to obtain tin ion intercalated Ti3C2 powder coated with tin dioxide;

[0079] (3) The assembly of the all-solid-state supercapacitor is the same as in Example 1

[0080] From Figure 10 the scanning electron microscope images shown, the multi-layer Ti3C2 powder without hexagonal pores intercalated with Sn 4+ has a significantly smaller specific surface area compared to the multi-layer hexagonal pore Ti3C2 powder intercalated with Sn in Example 1, and at the same time reduces the additional ion adsorption channels and redox sites. As can be seen from Table 1, the energy density of Comparative Example 1 is 277.58 F g 4+ , which is the relatively smallest. -1

[0081] Comparative Example 2

[0082] (1) Preparation of Ti3AlC2 precursor powder with hexagonal pores

[0083] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly according to a molar ratio of 5:1:1. Under the protection of an inert atmosphere of argon, put it into a vacuum hot-pressing sintering furnace. The power of the vacuum hot-pressing sintering furnace is 65 KW, the pressure of the pressing head is set to 20 T, and the diameter of the effective contact surface of the pressing head is Ф90 mm; use argon as the protective atmosphere in the furnace, the inflation pressure is set to 0.03 MPa, react at 700 °C for 6 hours, and after the reaction is completed, introduce liquid nitrogen for cooling for 1 h, and grind to 200 mesh to obtain the precursor powder with hexagonal pores;

[0084] (2) Simultaneously prepare Sn 4+ intercalated multi-layered hexagonal pore Ti3C2 powder by microwave-assisted etching and ion intercalation. Add SnCl4·5H2O to the mixed etching agent of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Among them, the molar ratio of HCl to CaF2 in the mixed solution is 5:4, and the concentration of HCl is 9 mol·L -1, the concentration of SnCl4·5H2O is 0.25 mol·L -1 , place 1 g of the precursor powder prepared in step (1) into a 20 mL SnCl4·5H2O-CaF2-HCl mixed solution. In a microwave reactor, at room temperature, under the power of 300 W, the frequency of 2.45 GHz, and the pressure of 2.0 Mpa, carry out microwave-assisted reaction in the microwave reactor, synchronously carry out etching and ion intercalation. The reaction time is 3 h. Then, wash away impurities with dilute hydrochloric acid with a concentration of 1 mol·L -1 . Then, perform ultrasonic treatment for 1 h. Put the suspension obtained after ultrasonic treatment into a centrifuge, with a centrifugal speed of 3000 rpm, and centrifuge for 15 min. After centrifugation, pour off the supernatant, take out the centrifuged precipitate, and wash it with deionized water until the solution pH = 6. Carry out vacuum filtration, and dry it in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ -intercalated multi-layer hexagonal pore Ti3C2 powder;

[0085] (3) Without microwave-assisted synthesis, directly use SnCl4·5H2O as the tin source to synthesize tin dioxide-coated tin ion-intercalated Ti3C2 powder. Dissolve 0.5 g of SnCl4·5H2O in 20 mL of deionized water to obtain an SnCl4·5H2O aqueous solution. Add 0.5 g of Sn 4+ -intercalated multi-layer hexagonal pore Ti3C2 powder prepared in step (2), then add NaOH to adjust the pH to 12, stir at room temperature for 30 min, then pour it into the inner lining of the reaction kettle, and react at room temperature for 3 h. After the reaction is completed, wash it with deionized water until the pH value is 7. Carry out vacuum filtration, and dry it in a vacuum drying oven at 80 °C for 8 hours to obtain tin dioxide-coated tin ion-intercalated Ti3C2 powder;

[0086] (4) The assembly of the all-solid-state supercapacitor is the same as in Example 1.

[0087] Comparative Example 2 was tested for charge-discharge cycles under the same conditions as in Example 1, as Figure 6 shown. The specific capacitance of Comparative Example 2 increases with the increase of charge-discharge cycles. The change range of the specific capacitance of Ti3C2 in Comparative Example 2 is relatively large, and the long-cycle charge-discharge is relatively unstable. When it reaches 50,000 cycles, the specific capacitance of Ti3C2 in Comparative Example 2 changes from 356.52 F g -1 to 244.13 F g -1 , and the specific capacitance decay rate is 31.52%. And, from Figure 7 the change curve of the energy density with the power density shown, it can be seen that the energy density of Ti3C2 in Comparative Example 2 decays more significantly with the increase of the power density. At the same time, from Figure 11As can be seen from the SEM images shown, for the tin ion intercalated Ti3C2 powder coated with tin dioxide synthesized without microwave assistance, the surface coating is uneven, which will lead to differences in electrochemical performance in different regions, affecting the stability and consistency of the overall performance and resulting in a small energy density. Moreover, the particle sizes of tin dioxide are uneven in length, resulting in uneven electrochemical active sites of Ti3C2 during the charge and discharge process, thus reducing the stability of the specific capacitance and energy density during long cycling.

[0088] In Comparative Example 3, etching and ion intercalation were carried out step by step.

[0089] (1) Prepare Ti3AlC2 precursor powder with hexagonal pores

[0090] Mix Ti3AlC2, ZnCl2, and CuCl2 evenly according to a molar ratio of 5:1:1. Under the protection of an inert gas argon, put them into a vacuum hot pressing sintering furnace. The power of the vacuum hot pressing sintering furnace is 65 KW, the pressure of the press head is set to 20 T, and the diameter of the effective contact surface of the press head is Ф90 mm; use argon as the protective atmosphere in the furnace, set the inflation pressure to 0.03 MPa, react at 700 °C for 6 hours, after the reaction is completed, introduce liquid nitrogen for cooling for 1 h, and grind to 200 mesh to obtain the precursor powder with hexagonal pores;

[0091] (2) Prepare multi-layer hexagonal pore Ti3C2 powder by microwave-assisted etching

[0092] Add CaF2 to HCl to prepare a CaF2-HCl mixed etching agent. Among them, the molar ratio of HCl to CaF2 in the mixed etching agent is 5:4, and the concentration of HCl is 9 mol·L -1 , place 1 g of the precursor powder prepared in step (1) in 20 mL of the CaF2-HCl mixed etching agent. In a microwave reactor, carry out microwave-assisted etching at room temperature with a power of 300 W, a frequency of 2.45 GHz, and a pressure of 2.0 Mpa. The reaction time is 3 h, then wash away the impurities with dilute hydrochloric acid with a concentration of 1 mol·L -1 Perform ultrasonic treatment for 1 h. Put the suspension obtained after ultrasonic treatment into a centrifuge, with a centrifugation speed of 3000 rpm and a centrifugation time of 15 min. After centrifugation is completed, pour off the supernatant, take out the centrifuged precipitate, wash it with deionized water until the solution pH = 6, perform vacuum filtration, and dry it in a vacuum drying oven at 80 °C for 8 h to obtain multi-layer hexagonal pore Ti3C2 powder;

[0093] (3) Prepare Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder

[0094] Place 1 g of the multi-layer hexagonal pore Ti3C2 powder prepared in step (2) in 20 mL with a concentration of 0.25 mol·L -1In a SnCl4·5H2O solution, magnetic stirring was carried out at a stirring speed of 500 rpm at room temperature for 3 h. The reaction suspension was placed in a centrifuge, and the centrifugation speed was 3000 rpm for 15 min. After centrifugation, the supernatant was poured off, and the centrifuged precipitate was taken out and washed with deionized water until the solution pH = 6. Vacuum filtration was carried out, and it was dried in a vacuum drying oven at 80 °C for 8 h to obtain Sn 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder;

[0095] (4) Using SnCl4·5H2O as a tin source, tin ion-intercalated Ti3C2 powder coated with tin dioxide was synthesized by microwave-assisted method. 0.5 g of SnCl4·5H2O was dissolved in 20 mL of deionized water to obtain an aqueous SnCl4·5H2O solution with a concentration of 0.75 mol·L -1 of SnCl4·5H2O. 0.5 g of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder prepared in step (2) was added, and then 0.7 g of NaOH was added to adjust the pH to 12. Stirring was carried out at room temperature for 30 min, and then it was poured into the inner lining of the reaction kettle. Under the power of 300 W, the frequency of 2.45 GHz and the pressure of 2.0 MPa, microwave-assisted reaction was carried out in a microwave reactor for 3 h. After the reaction was completed, it was washed with deionized water until the pH value was 7. Vacuum filtration was carried out, and it was dried in a vacuum drying oven at 80 °C for 8 hours to obtain tin ion-intercalated Ti3C2 powder coated with tin dioxide;

[0096] (5) The assembly of the all-solid-state supercapacitor was the same as in Example 1.

[0097] Figure 12 As can be seen from the XRD pattern analysis shown, compared with Comparative Example 3, the angle of the 002 peak in Example 1 shifted to the left by 2θ = 0.18°. Compared with Comparative Example 3, the etching and ion intercalation in Example 1 of the present invention can be carried out synchronously to further increase the layer spacing, provide a wider transmission channel for ions, and can significantly improve the pseudocapacitance performance of the material.

[0098] The electrochemical performance tables of Examples 1-3 and Comparative Examples 1-3 of the present invention are shown in Table 1:

[0099] Table 1

[0100] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Specific capacitance 685.62 F / g 451.04 F / g 407.23 F / g 277.58 F / g 356.52 F / g 477.13 F / g Energy density 274.87 W / kg 180.82 W / kg 163.26 W / kg 111.28 W / kg 142.93 W / kg 191.28 W / kg

[0101] Combined with Figure 6 and Table 1, the tin ion-intercalated Ti3C2 powder coated with tin dioxide in Example 1 of the present invention greatly increases the total specific capacitance, and the total specific capacitance can reach 685.62 F g -1 , from Figure 6It can be seen that during the long-term charge-discharge cycle of up to 50,000 cycles, the specific capacitance of SnO2@Ti3C2 in Example 1 decreased from 685.62 F·g -1 to 678.76 F·g -1 , with a specific capacitance decay rate of 1%, indicating good cycle stability. Combining Figure 1 with Table 1, it can be known that the all-solid-state supercapacitor of Example 1 of the present invention, namely tin dioxide-coated tin ion intercalated Ti3C2 powder, greatly improves the energy density, and the energy density can reach 274.87 Wh kg -1 , achieving high-energy-density energy storage.

[0102] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Preparation method of hexagonal pore SnO2@Ti3C2 electrode material for high energy density all-solid-state supercapacitor, characterized by: It includes the following steps: (1) Prepare Ti3AlC2 precursor powder with hexagonal pores: Mix Ti3AlC2, ZnCl2, and CuCl2 evenly at a molar ratio of (5 - 7):1:

1. Under the protection of an inert atmosphere, react in a vacuum hot-pressing sintering furnace. After the reaction, introduce liquid nitrogen for cooling, and then grind to 200 mesh to obtain the precursor powder with hexagonal pores; (2)Simultaneously prepare Sn intercalated multi-layer hexagonal pore Ti3C2 powder by microwave-assisted etching and ion intercalation 4+ : Add SnCl4·5H2O to the mixed etchant of CaF2 and HCl to prepare a SnCl4·5H2O-CaF2-HCl mixed solution. Add the precursor powder with hexagonal pores prepared in step (1), mix evenly, pour it into a microwave reactor at room temperature, carry out microwave-assisted etching and ion intercalation in the microwave reactor. Then, perform pickling, followed by ultrasonic treatment at room temperature for 1 h, centrifugation. Retain the precipitate and wash it with deionized water until the solution pH = 6. Perform vacuum filtration and dry it in a vacuum drying oven to obtain Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder; (3) Use SnCl4·5H2O as a tin source to synthesize SnO2-coated tin ion-intercalated Ti3C2 powder through microwave-assisted synthesis: The Sn prepared in step (2) 4+ Intercalated multi-layer hexagonal pore Ti3C2 powder and an aqueous solution of SnCl4·5H2O are added with NaOH to adjust the pH value to 12 - 13, stirred at room temperature for 20 - 40 min, then placed in the inner lining of a reaction kettle and prepared by microwave-assisted using a microwave reactor, washed with deionized water until the pH value is 6 - 7, and dried in a vacuum drying oven to obtain tin dioxide-coated tin ion-intercalated Ti3C2 powder.

2. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In step (1), the inert atmosphere is an argon atmosphere; the pressure of the indenter of the vacuum hot-pressing sintering furnace is set to 20T, the reaction temperature in the vacuum hot-pressing sintering furnace is 700°C - 850°C, and the reaction time is 6h - 12h.

3. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In step (2), in the SnCl4·5H2O-CaF2-HCl mixed solution, the concentration of HCl is 7 mol·L -1 ~9 mol·L -1 , the molar ratio of HCl to CaF2 is 5:4, and the concentration of SnCl4·5H2O is 0.25 mol·L -1 , and the mass-volume ratio of the precursor powder with hexagonal pores to the SnCl4·5H2O-CaF2-HCl mixed solution is 1:20 g·mL -1 .

4. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In step (3), the concentration of the SnCl4·5H2O aqueous solution is 0.07 mol·L -1 ~0.15 mol·L -1 , and the mass ratio of Sn 4+ intercalated multi-layer hexagonal pore Ti3C2 powder to SnCl4·5H2O in the SnCl4·5H2O aqueous solution is 1:(1:2).

5. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 3 or 4, characterized in that: In step (1), the molar ratio of Ti3AlC2 to ZnCl2 and CuCl2 is 5:1:1; in step (2), in the SnCl4·5H2O-CaF2-HCl mixed solution, the concentration of HCl is 9 mol·L -1 .

6. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In step (3), in the aqueous solution of SnCl4·5H2O, the mass-volume ratio of SnCl4·5H2O to deionized water is 1:40 g / mL.

7. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In step (1), when liquid nitrogen is introduced for cooling, the cooling time is 1 hour; in step (2), during pickling, it is washed with dilute hydrochloric acid with a concentration of 1 mol·L -1 . In step (2), during centrifugation, the centrifugation speed is 3000 rpm to 5000 rpm, and the centrifugation time is 15 min.

8. The preparation method of the hexagonal pore SnO2@Ti3C2 electrode material for the high energy density all-solid-state supercapacitor according to claim 1, characterized in that: In steps (2) and (3), when the microwave reactor is assisted by microwaves, the microwave-assisted power is 300W, the frequency is 2.45 GHz, the pressure is 2.0 MPa, and the reaction time is 3h.

9. Application of the hexagonal pore SnO2@Ti3C2 electrode material prepared by the preparation method as described in claim 1 as a positive electrode material and a negative electrode material in an all-solid-state supercapacitor.

10. An application as described in claim 9, characterized in that: all-solid-state The supercapacitor is assembled specifically as follows: (1) Preparation of the negative electrode of a high-energy-density all-solid-state supercapacitor: Mix the SnO2@Ti3C2 electrode material, acetylene black, and PVDF at a mass ratio of 8.5:1:0.5, add NMP to form a mixed slurry, evenly coat it on 1 cm × 1 cm nickel foam, roll it flat to form an electrode sheet, and dry it in a vacuum drying oven to obtain the negative electrode material; (2) Preparation of the positive electrode of the high-energy-density all-solid-state supercapacitor electrode: Mix Sn 4+ The intercalated Ti3C2 electrode material, acetylene black, and PVDF are mixed in a mass ratio of 8.5:1:0.5, and NMP is added dropwise to form a mixed slurry. The slurry is evenly coated on a 1 cm × 1 cm nickel foam, rolled flat to form an electrode sheet, and then dried in a vacuum drying oven to obtain the positive electrode material; (3) Preparation of the electrolyte of the high-energy-density all-solid-state supercapacitor: Mix Li2S, P2S5, and LiCl at a molar ratio of 4.2:1:2 and grind them, and then sinter them in a vacuum sintering furnace at 500°C under vacuum for 5h. After cooling, obtain the solid electrolyte; (4) Assembly of the high-energy-density all-solid-state supercapacitor: Assemble the positive electrode sheet, negative electrode sheet, and solid electrolyte into an all-solid-state supercapacitor.

Images