Preparation method of printing flexible supercapacitor based on MnO2 / MXene
The preparation of MnO2/MXene composite ink solved the problem of Ti3C2Tx sheet re-stacking, realizing a flexible supercapacitor with high specific capacitance and high energy density, simplifying the preparation process and reducing costs.
Patent Information
- Application Number
- CN202511246801.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2025-11-07
AI Technical Summary
In the current process of preparing thin film electrodes, single Ti3C2Tx sheets tend to be re-stacked, resulting in a low specific capacity of the electrode material.
By using MnO2/MXene composite ink, single-layer or few-layer exfoliation is achieved through a gentle MXene exfoliation technique, and the microscale of the two-dimensional active material MnO2 nanosheets is controlled. By combining the microscale matching of MXene and MnO2 nanosheets, flexible supercapacitor electrodes printed with composite ink are prepared.
It improves the specific capacitance characteristics of electrode materials, simplifies the preparation process of supercapacitors, reduces material costs, and maintains more than 70% of the initial value of specific capacitance after 10,000 charge-discharge cycles, with an areal specific capacitance of 80 mF/cm2.
Smart Images
Figure CN120914031A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of printed energy storage devices. BACKGROUND
[0002] Super capacitors, due to their excellent electrochemical energy storage performance, have gradually become an important class of energy storage devices. Generally speaking, the energy density of super capacitors is several tens to hundreds of times that of traditional capacitors. In addition, due to its excellent charge and discharge mechanism, super capacitors can achieve a large amount of energy transmission in a short time, so its power density is significantly higher than that of batteries. In addition to its short charging time, long service life, and good low-temperature performance, it is unmatched by battery energy storage materials. Because it can provide super large current power in a short time, it can be used as a starting power source for large machinery in industry and agriculture, and can also ensure the smooth start of tanks and armored vehicles in low-temperature harsh environments, while also serving as a pulse energy source for laser weapons. With the upgrading of China's industrial production capacity and the replacement of military equipment, the demand for super capacitors is increasing. With the development of electronic components and the pursuit of precision, in order to meet the demand for lightweight and portable electronic devices, it is urgent to develop compatible high-energy-density and flexible micro energy storage devices. Micro super capacitors (MSCs) have excellent energy density and cycle life, and are currently a research hotspot in the field of micro energy storage devices. In addition, flexible super capacitors can also provide stable power for wearable devices, so the development of flexible electrodes and super capacitors is of great significance.
[0003] MXene is a general term for a series of two-dimensional transition metal carbides, nitrides or carbonitrides. Due to its excellent physical and chemical properties, it has attracted people's attention, and more than 30 kinds of MXene materials have been found. The presence of surface end groups on MXene makes it have good hydrophilicity and reactivity, and its negative Zeta potential makes MXene material conducive to forming a stable dispersion in aqueous solution and other different solvents. In the structure of the most common Ti3C2T x , the Ti3C2core part has high metal-like conductivity and excellent electrochemical energy storage characteristics, so MXene material is much better than existing carbon materials such as graphene and flexible graphite when used as a super capacitor electrode material.
[0004] However, the existing single Ti3C2T x thin sheet tends to restack during the preparation of the thin film electrode, resulting in a problem of low specific capacity of the electrode material. SUMMARY
[0005] The present application solves the problem of the existing single Ti3C2T xThe flakes tend to restack during the preparation of the thin film electrode, resulting in the problem of low specific capacity of the electrode material, and thus a preparation method of a printed flexible supercapacitor based on MnO2 / MXene is provided.
[0006] A preparation method of a printed flexible supercapacitor based on MnO2 / MXene is performed in the following steps:
[0007] I. Preparation of Ti3C2T x
[0008] Mix H2O and concentrated hydrochloric acid uniformly to obtain an acid solution, add LiF to the acid solution and stir, then add dry Ti3AlC2 powder and stir, seal the reaction kettle, then etch at a temperature of 30-50 DEG C for 0.5-24 h, and finally centrifugal wash, freeze and vacuum dry to obtain Ti3C2T x powder;
[0009] II. Preparation of printable ink
[0010] Mix deionized water, hydroxypropyl methyl cellulose, MnO2 dispersion liquid and Ti3C2T x powder uniformly to obtain MnO2 / MXene printable ink;
[0011] III. Assembly of supercapacitor
[0012] 1. Apply and print the MnO2 / MXene printable ink on both sides of the electrode, and then naturally dry to obtain a thin film electrode;
[0013] 2. Assemble in the order of from bottom to top as follows: non-conductive flexible substrate, thin film electrode, LiCl / PVA gel electrolyte layer, filter paper, LiCl / PVA gel electrolyte layer and thin film electrode, to obtain a sandwich structure of electrode-electrolyte-electrode;
[0014] 3. Apply conductive silver paste on both ends of the electrode-electrolyte-electrode sandwich structure, and wrap the electrode with aluminum foil to obtain a supercapacitor.
[0015] The beneficial effects of the present application are:
[0016] 1. The mild MXene exfoliation technology is selected in the method to realize single-layer or few-layer exfoliation of MXene, which reduces the groups and wrinkles on the surface of MXene on the basis of maintaining the integrity of the two-dimensional sheet of MXene, so as to exert the excellent conductive performance of MXene.
[0017] 2. By regulating the micro size of the two-dimensional active material MnO2 nanosheet, the micro size matching of MXene and the two-dimensional active material is realized, and very high specific capacitance characteristics are realized. MXene has a metallic property, and its excellent conductivity can effectively improve the electrochemical activity of the two-dimensional active material.
[0018] 3. The MXene, the two-dimensional active material MnO2 nanosheet and the binder are made into a composite ink, which can save the mixing, coating and other processes in the preparation process of the supercapacitor, thereby simplifying the preparation process of the supercapacitor. A flexible supercapacitor electrode printed with the composite ink is prepared, and an asymmetric all-solid-state flexible supercapacitor is assembled, and the area specific capacitance reaches 80 mF / cm 2 After 10,000 times of charging and discharging, the specific capacitance is greater than 70% of the initial value.
[0019] 4. The two-dimensional active material MnO2 nanosheet is added to the MXene ink, which can effectively reduce the material cost of the composite ink while improving the electrochemical energy storage performance of the composite ink, so that it has certain economic cost advantage as a high-energy-density battery material in mass production.
[0020] The application relates to a preparation method of a printed flexible supercapacitor based on MnO2 / MXene. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The Ti3C2T x powder is prepared by one step of the embodiment.
[0022] Figure 2 The scanning electron microscope image of the MnO2 / MXene printable ink prepared by one step two of the embodiment. DETAILED DESCRIPTION
[0023] Specific embodiment one: the preparation method of the printed flexible supercapacitor based on MnO2 / MXene in the embodiment is carried out according to the following steps:
[0024] I. Preparation of Ti3C2T x
[0025] H2O and concentrated hydrochloric acid are uniformly mixed to obtain an acid solution, LiF is added to the acid solution and stirred, dry Ti3AlC2 powder is added and stirred, a reaction kettle is sealed, then etching is carried out at a temperature of 30 DEG C to 50 DEG C for 0.5 h to 24 h, and finally centrifugal washing, freezing and vacuum drying are carried out to obtain Ti3C2T x powder;
[0026] II. Preparation of printable ink:
[0027] deionized water, hydroxypropyl methyl cellulose, MnO2 dispersion liquid and Ti3C2T x The powders were mixed uniformly to obtain the MnO2 / MXene printable ink;
[0028] III. Assembly of the supercapacitor:
[0029] ① The MnO2 / MXene printable ink was coated and printed on both sides of the electrode, and then naturally dried to obtain a thin film electrode;
[0030] ② The electrode-electrolyte-electrode sandwich structure was assembled in the order of a non-conductive flexible substrate, a thin film electrode, a LiCl / PVA gel electrolyte layer, filter paper, a LiCl / PVA gel electrolyte layer, and a thin film electrode from bottom to top;
[0031] ③ The conductive silver paste was coated on both ends of the electrode-electrolyte-electrode sandwich structure, and the electrode was wrapped with an aluminum foil to obtain a supercapacitor.
[0032] In step one of the embodiment, MXene was prepared by acid etching. HF etching MAX phase Ti3AlC2 was synthesized by in-situ reaction of concentrated HCl and LiF to obtain Ti3C2T x MXene nanosheets.
[0033] In this embodiment, MnO2 / MXene ink was prepared from MnO2 and MXene, which combined the two characteristics of MXene, i.e., forming a stable colloidal dispersion in water and high-density energy storage materials. The printable ink used for printing should have high conductivity and adjustable viscosity. The ink showed pseudoplastic non-Newtonian fluid behavior, which could meet the requirements of coating on paper and print clear MnO2 / MXene ink on different substrates, providing a technical research basis for energy storage applications of wearable electronic devices. In the conductivity test, the MnO2 / MXene printable ink sample showed slightly better conductivity than the MXene printed ink. At a high scan rate, the MnO2 / MXene ink printed sample showed better area capacitance than the MXene printed sample. The incorporation of MnO2 slowed down the impact of electrolyte particle diffusion on the area capacitance of the printed electrode due to the increase in scan rate. The constant current charge and discharge experiment proved the good charge and discharge rate performance of the printed sample. The flexible supercapacitor electrode printed with the composite ink was assembled into an asymmetric all-solid-state flexible supercapacitor, and the area specific capacitance reached 80 mF / cm 2 After 10,000 charge and discharge cycles, the specific capacitance was greater than 70% of the initial value. The above results provide a practical strategy for the preparation of two-dimensional MXene functional materials with high efficiency, high resolution patterning, and complex structure. The construction of a self-supporting flexible thin film electrode with high stability and the use of interlayer structure and Ti3C2Tx The synergistic effect of the two further improves the electrochemical performance to obtain a flexible electrode material with high specific capacitance, high power density and high energy density, thereby promoting the development of the flexible electrode material in portable electronic product applications.
[0034] The beneficial effects of the embodiment are:
[0035] 1. The method of the embodiment uses a mild MXene exfoliation technique to achieve single-layer or few-layer exfoliation of MXene, thereby reducing the groups and wrinkles on the surface of MXene while maintaining the integrity of the two-dimensional sheets of MXene, so as to exert the excellent conductive performance of MXene.
[0036] 2. By adjusting the micro-size of the two-dimensional active material MnO2 nanosheet, the micro-size matching of MXene and the two-dimensional active material is achieved, and very high specific capacitance characteristics are achieved. MXene has metallic properties, and its excellent conductive performance can effectively improve the electrochemical activity of the two-dimensional active material.
[0037] 3. The composite ink prepared by mixing MXene, two-dimensional active material MnO2 nanosheet and binder can save the mixing and coating processes in the preparation process of supercapacitors, thereby simplifying the preparation process of supercapacitors. A flexible supercapacitor electrode printed with the composite ink is prepared, and an asymmetric all-solid-state flexible supercapacitor is assembled, so that the area specific capacitance reaches 80 mF / cm 2 After 10,000 times of charging and discharging, the specific capacitance is greater than 70% of the initial value.
[0038] 4. The addition of two-dimensional active material MnO2 nanosheet to the MXene ink not only improves the electrochemical energy storage performance of the composite ink, but also effectively reduces the material cost of the composite ink, so that it has certain economic cost advantage as a high-energy-density battery material in mass production.
[0039] Specific implementation method two: The difference between the embodiment and the specific implementation method one is that the volume ratio of H2O to concentrated hydrochloric acid in step one is 1:(3-4); the concentration of the concentrated hydrochloric acid in step one is 10 mol / L-14 mol / L; the mass-to-volume ratio of LiF to acid solution in step one is 1g:(8-12)mL; and the mass-to-volume ratio of dry Ti3AlC2 powder to acid solution in step one is 1g:(20-40)mL. The rest is the same as the specific implementation method one.
[0040] Specific embodiment three: the difference between this embodiment and one or two of the specific embodiments is that in step one, LiF is added to the acid solution under the condition that the rotation speed is 300 r / min-500 r / min, and stirred for 10 min-6 h, and then dry Ti3AlC2 powder is added in multiple times under the condition that the rotation speed is 500 r / min-800 r / min, and stirred for 24 min-72 min. The others are the same as one or two of the specific embodiments.
[0041] Specific embodiment four: the difference between this embodiment and one to three of the specific embodiments is that the centrifugal washing, freezing and vacuum drying in step one are specifically performed as follows: with deionized water as the washing liquid, centrifugal washing is performed under the condition that the rotation speed is 3500 r / min-4000 r / min, and the supernatant is removed, and the centrifugal washing is repeated until the supernatant is dark green and pH≥6, then the supernatant is removed and the precipitate is collected, and freeze drying is performed under the condition that the temperature is -60℃--80℃, and then vacuum drying is performed under the condition that the temperature is 10℃-20℃ for 22 h-26 h. The others are the same as one to three of the specific embodiments.
[0042] Specific embodiment five: the difference between this embodiment and one to four of the specific embodiments is that the Ti3C2T x powder and deionized water in step two is 1:(2-3); the mass ratio of the Ti3C2T x powder and hydroxypropyl methyl cellulose in step two is 1:(0.05-0.2); the mass ratio of the Ti3C2T x powder and MnO2 in the MnO2 dispersion liquid in step two is 1:(0.05-0.2); the concentration of MnO2 in the MnO2 dispersion liquid in step two is 0.5 mg / mL-2 mg / mL. The others are the same as one to four of the specific embodiments.
[0043] Specific embodiment six: the difference between this embodiment and one to five of the specific embodiments is that in step two, deionized water, hydroxypropyl methyl cellulose, MnO2 dispersion liquid and Ti3C2T x powder are mixed uniformly, which is specifically performed as follows: under the condition that the stirring speed is 300 r / min-400 r / min and the temperature is 30℃-45℃, hydroxypropyl methyl cellulose is added to deionized water for constant temperature stirring for 10 min-30 min to obtain an HPMC solution, the HPMC solution is naturally cooled to room temperature, then the MnO2 dispersion liquid and Ti3C2T xThe powder is continuously stirred at a stirring speed of 50 r / min to 100 r / min for 20 min to 40 min, and then vacuum degassed for 20 min to 40 min to obtain the MnO2 / MXene printable ink. The other aspects are the same as those in Embodiments One to Five.
[0044] Embodiment Seven: Different from one of Embodiments One to Six, in step three ①, the MnO2 / MXene printable ink is coated and printed on the two side surfaces of the electrode with a coating thickness of 0.01 mm to 0.1 mm, and then naturally dried to obtain the thin film electrode. The other aspects are the same as those in Embodiments One to Six.
[0045] Embodiment Eight: Different from one of Embodiments One to Seven, in step three ②, the LiCl / PVA gel electrolyte layer is specifically obtained by coating and naturally drying the LiCl / PVA gel electrolyte, and the thickness of the LiCl / PVA gel electrolyte layer on the two sides of the filter paper is 0.01 mm to 0.1 mm; the LiCl / PVA gel electrolyte is specifically prepared by the following steps: under the conditions of a stirring speed of 300 r / min to 400 r / min and a temperature of 30℃ to 50℃, polyvinyl alcohol is added to deionized water and stirred for 5 min to 10 min, then heated to 70℃ to 90℃ at a heating rate of 2℃ / min to 5℃ / min, and under the conditions of a stirring speed of 300 r / min to 400 r / min and a temperature of 70℃ to 90℃, LiCl is added and water-bathed for 0.5 h to 2 h; the mass ratio of the polyvinyl alcohol to the deionized water is 1 g:(5-20) mL; and the mass ratio of the polyvinyl alcohol to LiCl is 1:(0.5-2). The other aspects are the same as those in Embodiments One to Seven.
[0046] Embodiment Nine: Different from one of Embodiments One to Eight, in step three ②, the non-conductive flexible substrate is a PET plate. The other aspects are the same as those in Embodiments One to Eight.
[0047] Embodiment Ten: Different from one of Embodiments One to Nine, in step three ②, the contact area between the thin film electrode and the LiCl / PVA gel electrolyte layer in the sandwich structure of electrode-electrolyte-electrode is 0.2 cm 2 ~1 cm 2 . The other aspects are the same as those in Embodiments One to Nine.
[0048] The beneficial effects of the present application are verified by the following embodiments:
[0049] Embodiment One:
[0050] A preparation method of a printed flexible supercapacitor based on MnO2 / MXene, which is carried out in the following steps:
[0051] I. Ti3C2T x powder is prepared as follows:
[0052] H2O and concentrated hydrochloric acid are uniformly mixed to obtain an acid solution, LiF is added to the acid solution under the condition that the rotation speed is 350 r / min and stirred for 30 min, then dry Ti3AlC2 powder is added in two times under the condition that the rotation speed is 500 r / min and stirred for 25 min, the reaction kettle is sealed, then etching is carried out under the condition that the temperature is 40℃ for 24 h, finally centrifugal washing, freezing and vacuum drying are carried out to obtain Ti3C2T x powder;
[0053] The volume ratio of H2O to concentrated hydrochloric acid is 1:3.8; the concentration of the concentrated hydrochloric acid is 12 mol / L; the mass ratio of LiF to the acid solution in step I is 1g:10mL; the mass ratio of the dry Ti3AlC2 powder to the acid solution is 1g:30mL.
[0054] II. Preparation of a printable ink:
[0055] Hydroxypropyl methyl cellulose is added to deionized water under the condition that the stirring speed is 350 r / min and the temperature is 40℃, constant temperature stirring is carried out for 20 min to obtain an HPMC solution, the HPMC solution is naturally cooled to room temperature, then MnO2 dispersion liquid and Ti3C2T x powder are added, stirring is continued under the condition that the stirring speed is 50 r / min for 30 min, and vacuum degassing is carried out for 30 min to obtain a MnO2 / MXene printable ink;
[0056] The mass ratio of Ti3C2T x powder to deionized water is 1:2.4; the mass ratio of Ti3C2T x powder to hydroxypropyl methyl cellulose is 1:0.1; the mass ratio of Ti3C2T x powder to MnO2 in the MnO2 dispersion liquid is 1:0.1; the concentration of MnO2 in the MnO2 dispersion liquid is 1mg / mL;
[0057] III. Assembly of a supercapacitor:
[0058] ①The MnO2 / MXene printable ink is coated and printed on the two side surfaces of the electrode with a coating thickness of 0.02 mm, and then naturally dried to obtain a thin film electrode;
[0059] The electrode is a supercapacitor active electrode;
[0060] ②Cut the thin film electrode into two pieces of the same size, and assemble them in the order of flexible substrate, thin film electrode, LiCl / PVA gel electrolyte layer, filter paper, LiCl / PVA gel electrolyte layer and thin film electrode from bottom to top to obtain an electrode-electrolyte-electrode sandwich structure;
[0061] ③Coat the electrodes at both ends of the electrode-electrolyte-electrode sandwich structure with conductive silver paste and wrap the electrodes with aluminum foil to obtain a supercapacitor.
[0062] The centrifugal washing, freezing and vacuum drying in step one are specifically performed as follows: using deionized water as the washing liquid, centrifuging at a speed of 3500 r / min for 5 min, removing the supernatant, repeating the centrifugation until the supernatant is dark green and the pH is 8, then removing the supernatant and collecting the precipitate, freezing and drying at a temperature of -80℃, and then vacuum drying at a temperature of 15℃ for 24 h.
[0063] The LiCl / PVA gel electrolyte layer in step three ② is obtained by coating and naturally drying the LiCl / PVA gel electrolyte, and the thickness of the LiCl / PVA gel electrolyte layer on both sides of the filter paper is 0.04 mm; the LiCl / PVA gel electrolyte is specifically prepared as follows: under the conditions of a stirring speed of 350 r / min and a temperature of 40℃, polyvinyl alcohol is added to deionized water and stirred for 5 min, then heated to 80℃ at a heating rate of 5℃ / min, and under the conditions of a stirring speed of 350 r / min and a temperature of 80℃, LiCl is added and water bathed for 1 h; the mass ratio of polyvinyl alcohol to deionized water is 1 g:10 mL; and the mass ratio of polyvinyl alcohol to LiCl is 1:1.
[0064] The flexible non-conductive substrate in step three ② is a PET plate.
[0065] The contact area of the thin film electrode and the LiCl / PVA gel electrolyte layer in the electrode-electrolyte-electrode sandwich structure in step three ② is 0.5 cm 2 .
[0066] Example two: different from example one is that in step one, LiF is added to the acid solution and stirred for 6 h at a speed of 300 r / min. The others are the same as example one.
[0067] Figure 1 The scanning electron microscope image of the Ti3C2T x powder prepared in step one of the example; from the figure, it can be seen that Ti3C2T x is a relatively transparent flaky structure.
[0068] Figure 2 The scanning electron microscope image of the MnO2 / MXene printable ink prepared in Example Step 2; as can be seen from the figure, it presents a wrinkled filament, proving that the prepared MnO2 / MXene has a two-dimensional layered morphology structure.
[0069] The supercapacitor prepared in Example 1 has an area specific capacitance of 80 mF / cm 2 .
[0070] The supercapacitor prepared in Example 2 has an area specific capacitance of 85 mF / cm 2 .
Claims
1. A method for preparing a printed flexible supercapacitor based on MnO2 / MXene, characterized in that It is carried out in the following steps: I. Ti3C2T x Preparation: Mixing H2O and concentrated hydrochloric acid uniformly to obtain an acid solution, stirring LiF into the acid solution, then stirring dry Ti3AlC2 powder into the acid solution, sealing the reactor, etching at a temperature of 30-50℃ for 0.5-24h, and finally centrifuging, washing, freezing and vacuum drying to obtain Ti3C2T x powder; II. Preparation of printable ink: Deionized water, hydroxypropyl methylcellulose, Mn02dispersion liquid and Ti3C2T x The powders are mixed uniformly to obtain the Mn02 / MXene printable ink; III. Assembly of supercapacitor: ①MnO2 / MXene printable ink is coated and printed on both sides of the electrode surface, and then naturally dried to obtain a thin film electrode; ②The electrode-electrolyte-electrode sandwich structure is obtained by assembling in the order of non-conductive flexible substrate, thin film electrode, LiCl / PVA gel electrolyte layer, filter paper, LiCl / PVA gel electrolyte layer and thin film electrode from bottom to top; ③The conductive silver paste is coated on both ends of the electrode-electrolyte-electrode sandwich structure, and the electrode is wrapped with aluminum foil to obtain a supercapacitor.
2. The method according to claim 1, characterized in that The volume ratio of H2O to concentrated hydrochloric acid in step one is 1:(3-4); the concentration of concentrated hydrochloric acid in step one is 10-14 mol / L; the mass to volume ratio of LiF to acid solution in step one is 1g:(8-12)mL; the mass to volume ratio of dry Ti3AlC2 powder to acid solution in step one is 1g:(20-40)mL.
3. The method according to claim 1, wherein In step one, LiF is added to the acid solution and stirred for 10-6h at a speed of 300-500r / min, and then dry Ti3AlC2 powder is added in multiple times and stirred for 24-72min at a speed of 500-800r / min.
4. The method of claim 1, wherein the method is characterized by The centrifugal washing, freezing and vacuum drying in step one are carried out in the following steps: using deionized water as the washing liquid, centrifuging at a speed of 3500-4000r / min for 5-8min, removing the supernatant, repeating the centrifugation until the supernatant is dark green and pH≥6, then removing the supernatant and collecting the precipitate, freezing and drying at a temperature of-60℃ to-80℃, and then vacuum drying at a temperature of 10-20℃ for 22-26h.
5. The method of claim 1, wherein the method is characterized by Ti3C2T in step two x The mass ratio of the powder to deionized water is 1:(2~3); Ti3C2T in step two x The mass ratio of the powder to hydroxypropyl methyl cellulose is 1:(0.05~0.2); Ti3C2T in step two x The mass ratio of the powder to MnO2 in the MnO2 dispersion is 1:(0.05~0.2); the concentration of MnO2 in the MnO2 dispersion in step two is 0.5mg / mL~2mg / mL.
6. The method of claim 1, wherein the method is characterized by The deionized water, hydroxypropyl methyl cellulose, MnO2 dispersion liquid and Ti3C2T x The powders are mixed uniformly, specifically in the following steps: under the condition that the stirring speed is 300 r / min~400 r / min and the temperature is 30℃~45℃, hydroxypropyl methyl cellulose is added into deionized water for constant temperature stirring for 10 min~30 min to obtain an HPMC solution, the HPMC solution is naturally cooled to room temperature, and then the MnO2 dispersion liquid and Ti3C2T x The powders are mixed uniformly, specifically in the following steps: under the condition that the stirring speed is 300 r / min~400 r / min and the temperature is 30℃~45℃, hydroxypropyl methyl cellulose is added into deionized water for constant temperature stirring for 10 min~30 min to obtain an HPMC solution, the HPMC solution is naturally cooled to room temperature, and then the MnO2 dispersion liquid and Ti3C2T 7. The method according to claim 1, wherein In step three ①, MnO2 / MXene printable ink is coated and printed on both sides of the electrode surface with a coating thickness of 0.01-0.1mm, and then naturally dried to obtain a thin film electrode. In step three ①, MnO2 / MXene printable ink is coated and printed on both sides of the electrode surface with a coating thickness of 0.01-0.1mm, and then naturally dried to obtain a thin film electrode.
8. The method according to claim 1, wherein The LiCl / PVA gel electrolyte layer in step three 2 is prepared by coating and naturally drying the LiCl / PVA gel electrolyte, and the thickness of the LiCl / PVA gel electrolyte layers on both sides of the filter paper is 0.01mm-0.1mm; the LiCl / PVA gel electrolyte is prepared by the following steps: under the conditions of a stirring speed of 300r / min-400r / min and a temperature of 30℃-50℃, polyvinyl alcohol is added into deionized water and stirred for 5min-10min, then heated to 70℃-90℃ at a heating speed of 2℃ / min-5℃ / min, under the conditions of a stirring speed of 300r / min-400r / min and a temperature of 70℃-90℃, LiCl is added and water-bathed for 0.5h-2h; the mass of the polyvinyl alcohol to the volume of the deionized water is 1g:(5-20)mL; the mass ratio of the polyvinyl alcohol to LiCl is 1:(0.5-2).
9. The method according to claim 1, wherein The non-conductive flexible substrate in step three 2 is a PET plate.
10. The method of claim 1, wherein the method is characterized by The contact area of the thin film electrode with the LiCl / PVA gel electrolyte layer in the sandwich-like structure of electrode-electrolyte-electrode described in Step three ② is 0.2 cm 2 1 cm 2 .