阅读说明：本技术 一种碳纤维毡基柔性全固态非对称超级电容器及制备方法 (Carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor and preparation method thereof ) 是由 严学华 犹明瑜 张文静 李艳丽 潘建梅 程晓农 于 2021-03-19 设计创作，主要内容包括：本发明涉及一种碳纤维毡基柔性全固态非对称超级电容器及制备方法,属于新能源材料与器件研究领域。本发明通过混酸酸化得到活化碳纤维毡,进一步采用活化碳毡与其表面直接生长一维VO-(2)纳米带复合形成的二元材料作为正极材料,在碳毡上涂覆一层致密的活性炭作为负极材料。所述CFF@VO-(2)二元纳米复合材料尺寸均一、排列致密、赝电容效应显著,所述活性炭负极材料导电性好、稳定性、倍率性能优异。(The invention relates to a carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor and a preparation method thereof, and belongs to the field of research on new energy materials and devices. The invention obtains the activated carbon fiber felt by mixed acid acidification, and further adopts the activated carbon felt and the surface thereof to directly grow one-dimensional VO 2 The binary material formed by compounding the nano belts is used as a positive electrode material, and a layer of compact activated carbon is coated on the carbon felt and used as a negative electrode material. The CFF @ VO 2 The binary nano composite material has the advantages of uniform size, compact arrangement, obvious pseudo-capacitance effect, good conductivity, excellent stability and excellent rate performance.)

1. The carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor comprises a positive electrode, a negative electrode and a gel electrolyte, and is characterized in that the positive electrode is a homogeneous one-dimensional VO (volatile organic solvent) grown on the surface of a carbon fiber felt with a three-dimensional space structure₂A binary composite electrode material formed by orderly arranging nanobelts; the binary composite electrode material is VO (vanadium oxide) which is prepared by taking a plurality of fibrous carbon rods in a carbon felt as a supporting substrate and a conductive bracket₂The nanobelts are completely coated on the surface of the carbon felt in a winding state, the structure provides a large specific surface area and binding sites for a large number of functional groups, and meanwhile, the non-totally-enclosed three-dimensional structure provides a large amount of space for free flow of anions and cations in electrolyte and direct contact with an electrode material to generate effects and store energy, so that the activity of the electrode material is improved, and the electrochemical reaction rate of the electrode material is improved from the aspect of dynamics; the three-dimensional structure can also stably maintain VO₂The shape of the nano belt effectively avoids single film-shaped VO₂The accumulation is continuous, and the pseudo-capacitive performance of the capacitor is influenced.

2. The carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 1, wherein the negative electrode is made by coating a layer of activated carbon on a carbon felt.

3. The carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 1, wherein the gel electrolyte is a PVA/LiCl gel electrolyte.

4. The preparation method of the carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 1, which comprises the following specific steps:

(1) cleaning the surface of the carbon felt: ultrasonically cleaning a commercial carbon felt by using HCl solution, NaOH solution, ethanol solution and deionized water in sequence, and then drying the carbon felt in an oven for later use;

(2) activating the surface of the carbon felt: placing a piece of dry carbon felt with proper size in a beaker; are respectively configured with H₂SO₄Solution with HNO₃A solution; pouring the two into a beaker in sequence; stirring the beaker at a constant speed at room temperature, transferring the beaker to a 70 ℃ water bath kettle, and continuously stirring at a constant speed; after stirring, taking out the carbon felt and cleaning the carbon felt by using an ethanol solution; finally, drying the carbon felt and taking out the carbon felt to weigh the carbon felt;

(3) preparing a binary material: weighing in turn the quantity C₂H₂O₄·2H₂O、CTAB、NH₄VO₃Pouring the powder into a beaker with deionized water added in advance to obtain a mixed solution; stirring the mixed solution at a constant speed at room temperature, transferring the mixed solution to a constant-temperature water bath kettle at 75 ℃ after the color of the solution is observed to be changed from dark yellow to green and then to light blue, continuously stirring at a constant speed, and simultaneously immersing a piece of activated and dried carbon felt into a beaker for chemical bath deposition; stirring at constant speed for 40-60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 deg.C for 3 h; finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; to record VO carried on carbon felt₂The net mass of the nanoribbon;

(4) preparing an all-solid-state supercapacitor: calculating the load capacity of the negative active carbon according to the charge conservation law of the positive electrode and the negative electrode; weighing quantitative PVA, LiCl and deionized water to prepare PVA/LiCl gel electrolyte; respectively soaking the anode and the cathode in the gel electrolyte for 10-20 min; taking out and adding a diaphragm between the two electrodes; and then wrapping a layer of plastic film outside, and finally maintaining the device under certain pressure for a certain time to obtain the all-solid-state supercapacitor.

5. The method for preparing the carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 4, wherein in the step (1), the concentrations of the HCl solution and the NaOH solution are 1mol/L, the mass percentage concentration of the ethanol solution is 95%, and the ultrasonic cleaning time is controlled to be 15 min.

6. The method for preparing the carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 4, wherein in the step (2), H is₂SO₄Solution with HNO₃The molar concentration of the solution is kept consistent and is 1-6mol/L, H₂SO₄Solution with HNO₃The volume ratio of the solution is 3: 1; the stirring speed of the beaker at room temperature and in the water bath is controlled to be 900 r/min; stirring for 45 min; the mass percentage concentration of the ethanol solution adopted for cleaning is 95 percent, and the cleaning is carried out for three times; drying means drying in an oven at 65 ℃ for 5 h.

7. The method for preparing the carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor according to claim 4, wherein in the step (3), the C is₂H₂O₄·2H₂O、CTAB、NH₄VO₃And deionized water at a mass ratio of 0.6303-0.6325: 0.1-0.12: 0.2925-0.3035: 30, of a nitrogen-containing gas; wherein C is₂H₂O₄·2H₂O as an activator and CTAB as an initiator and inducer; stirring the mixed solution at room temperature at a constant speed, wherein the stirring speed is 1200 r/min; continuously stirring in a water bath kettle at a constant speed at a stirring speed of 900r/min for 40-60 min; VO loaded on carbon felt₂The net mass of the nanobelt is 1.58-2.47mg/cm²。

8. The method for preparing the carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor as claimed in claim 4, wherein in the step (4), the loading amount of the negative active carbon is 3.20-5.60mg/cm²(ii) a The mass ratio of PVA to LiCl to deionized water is 3-3.5: 6.3-6.56: 30-35; the pressure is 0.1-0.15 MPa; the maintaining time is 10-15 min.

Technical Field

The invention relates to a carbon fiber felt-based flexible all-solid-state asymmetric supercapacitor and a preparation method thereof, and belongs to the field of research on new energy materials and devices.

Background

As a new energy storage device, the super capacitor has a series of advantages of high charging and discharging speed, long service cycle and the like. The super capacitor mainly comprises three blocks, namely an electrode material, electrolyte and a diaphragm. The electrode material is the most critical factor for determining the performance of the device, and the super capacitor can be divided into three categories according to the difference of energy storage mechanisms of the electrode material: double layer capacitance, faraday pseudocapacitance, hybrid.

The electric double layer capacitance type and Faraday pseudo capacitance type materials have respective advantages and disadvantages. Single electric double layer materials, such as activated carbon, carbon cloth, etc., have good stability and rate capability, but have low specific capacitance. The specific capacitance value of a single pseudocapacitance material, such as manganese-based material, copper-based material and the like, is high, but the structure is easy to collapse, and ions are easy to accumulate. Therefore, researchers focus on the diversified and multidimensional field combining the carbon material and the pseudocapacitance material, and focus on the advantages of the carbon material and the pseudocapacitance material together, and meanwhile, the defects of the carbon material and the pseudocapacitance material are prevented from being exposed, and a device with excellent performance is prepared.

Among many pseudocapacitance type electrode materials, vanadium has rich valence and high redox activity. The compound of vanadium widely studied by researchers is V₂O₅、VO₂And the like. VO (vacuum vapor volume)₂The material has excellent electrochemical performance, and has the advantages of large theoretical specific capacity, wide voltage window, high energy density and the like. But VO₂There are also some disadvantages such as low electron conduction rate, slow ion diffusion rate, poor cycling stability, and poor rate capability. Therefore, it is necessary to subject VO to₂And measures such as modification are taken to improve the electrochemical performance of the catalyst.

In addition, the performance of the electrode material is closely related to the microstructure thereof, and the microstructure thereof determines the number of binding sites of the surface active substances (such as oxygen-containing functional groups) of the electrode material. How to design and prepare the nanoscale electrode material with uniform size, uniform appearance and large specific surface area so as to fully and stably load the binding sites of the surface active substances is one of the key problems in the current research. Compared to zero-dimensional nanoparticles or one-dimensionalNanowire, etc., one-dimensional ribbon VO₂The method has the more remarkable advantage that the one-dimensional strip-shaped structure has larger specific surface area, so that the movement of anions and cations in the electrolyte between the strips is facilitated, and the electrochemical reaction between the anions and the electrode material is promoted in dynamics. Currently, VO with one-dimensional ribbon structure₂There are few reports of use as a metamaterial.

On the other hand, with the help of the carbon fiber felt with a three-dimensional structure, the overall design of the composite material is a three-dimensional structure, and the performance of the device is comprehensively improved: (1) carbon fiber skeleton with high strength as VO₂VO, a growth substrate of₂The size and the shape of the carbon felt are controlled, and VO generated when the carbon felt is not introduced is effectively avoided₂Thick film belt, mass accumulation, different sizes and the like. (2) The three-dimensional conductive carbon felt with rich pore structure enhances VO₂The conductivity of the semiconductor improves the energy density and the power density of the device. (3) VO with high pseudocapacitance₂The carbon felt directly grows on the carbon felt, avoids the introduction of a conductive agent and a polymer binder in the test process, and has more real and reliable performance. (4) The introduction of the carbon felt with good flexibility and excellent mechanical property enables the preparation of the miniature flexible all-solid-state device to be realized, and the practical development of the device is promoted.

Currently, the main materials studied for the flexible substrates are metal substrates and highly conductive carbon materials. The conductive carbon material has the advantages of environmental friendliness, direct contact with human skin and the like, but the untreated flexible carbon substrate hardly reacts with an inorganic compound. Therefore, a stable and reliable method is designed and developed to grow one-dimensional VO with high pseudo capacitance on a carbon material substrate₂The nano-band electrode material and the binary material are used as the anode material of the flexible device, and have great significance for promoting the development of the electrode material of the super capacitor and the practical application of the device.

Disclosure of Invention

In order to solve the key problems, the invention firstly proposes that the mixed acid is used for activating the commercial carbon felt to ensure that the commercial carbon felt is rich in a large number of functional groups, and the mixed acid is further deposited on the activated carbon felt by a chemical bath for growingOne-dimensional VO₂The nanoribbon is used as a positive electrode material, and a novel flexible all-solid-state supercapacitor is designed.

The flexible all-solid-state supercapacitor comprises a positive electrode, a negative electrode and a gel electrolyte, and is characterized in that the positive electrode is a homogeneous one-dimensional VO (vanadium oxide) grown on the surface of a carbon fiber felt with a three-dimensional space structure₂The nano-belts are orderly arranged to form the binary composite electrode material. The binary composite electrode material is VO (vanadium oxide) which is prepared by taking a plurality of fibrous carbon rods in a carbon felt as a supporting substrate and a conductive bracket₂The nanobelts are completely wrapped on the surface of the carbon felt in a winding state, the structure provides a large specific surface area and binding sites for a large number of functional groups, and meanwhile, the non-totally-enclosed three-dimensional structure provides a large amount of space for free flow of anions and cations in electrolyte and direct contact with an electrode material to generate effects and store energy, so that the activity of the electrode material is improved, and the electrochemical reaction rate of the electrode material is improved from the aspect of dynamics. The three-dimensional structure can also stably maintain VO₂The shape of the nano belt effectively avoids single film-shaped VO₂The accumulation is continuous, and the pseudo-capacitive performance of the capacitor is influenced. The negative electrode is prepared by coating a layer of activated carbon on a carbon felt. As a typical carbon material, the activated carbon has the advantages of good conductivity, good stability and the like, and when the activated carbon is used as a cathode material of a supercapacitor, the excellent structural stability of the activated carbon can be utilized to improve the rate capability, the cycle life and the like of a device. The gel electrolyte is PVA/LiCl gel electrolyte. Compared with an aqueous electrolyte, the gel electrolyte obviously widens the working voltage interval due to the addition of the organic polymer. In addition, the gel electrolyte has an all-solid-state structure, so that a series of problems of volume expansion, liquid overflow and the like of a device can be solved, and the preparation and the practical application of the flexible super capacitor are guaranteed.

The preparation method of the flexible all-solid-state supercapacitor comprises the following steps:

(1) cleaning the surface of the carbon felt: the commercial carbon felt is sequentially cleaned by 1mol/L HCl solution, 1mol/L NaOH solution, 95% ethanol solution with mass concentration and deionized water in an ultrasonic mode, and then placed in an oven to be dried for later use.

(2) Activating the surface of the carbon felt: placing a piece of dry carbon felt with proper size in a beaker; respectively prepared with 1-6mol/L H₂SO₄Mixing the solution with 1-6mol/L HNO₃A solution; pouring the two into a beaker in sequence according to the volume ratio of 3: 1; stirring the beaker at room temperature for 45min at a constant speed; then transferring the mixture into a 70 ℃ water bath kettle and stirring the mixture for 45min at a constant speed; after stirring, taking out the carbon felt and cleaning the carbon felt with 95% ethanol solution by mass concentration for three times; and finally, drying the carbon felt for 5 hours in a drying oven at the temperature of 65 ℃, and taking out the carbon felt to weigh the carbon felt.

(3) Preparing a binary material: weighing in turn the quantity C₂H₂O₄·2H₂O、CTAB、NH₄VO₃Pouring the powder into a beaker with deionized water added in advance to obtain a mixed solution; stirring the mixed solution at a constant speed at room temperature, transferring the mixed solution to a constant-temperature water bath kettle at 75 ℃ after the color of the solution is observed to be changed from dark yellow to green and then to light blue, continuously stirring at a constant speed, and simultaneously immersing a piece of activated and dried carbon felt into a beaker for chemical bath deposition; stirring at constant speed for 40-60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 deg.C for 3 h; finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; to record VO carried on carbon felt₂Net mass of nanoribbons.

(4) Preparing an all-solid-state supercapacitor: calculating the load capacity of the negative active carbon according to the charge conservation law of the positive electrode and the negative electrode; weighing quantitative PVA, LiCl and deionized water to prepare PVA/LiCl gel electrolyte; respectively soaking the anode and the cathode in the gel electrolyte for 10-20 min; taking out and adding a diaphragm between the two electrodes; and then wrapping a layer of plastic film outside, and finally maintaining the device under certain pressure for a certain time to obtain the all-solid-state supercapacitor.

In the step (1), the ultrasonic cleaning time is controlled to be 15 min.

H added in the step (2) above₂SO₄Solution with HNO₃The molarity of the solution should be kept consistent, with volumes of 60mL and 20mL, respectively.

In the step (2), the stirring speed of the beaker at room temperature and the stirring speed of the beaker in the water bath are both controlled to be 900 r/min.

In the above step (3), said C₂H₂O₄·2H₂O、CTAB、NH₄VO₃And deionized water at a mass ratio of 0.6303-0.6325: 0.1-0.12: 0.2925-0.3035: 30. wherein C is₂H₂O₄·2H₂O as an activator and CTAB as an initiator and inducer.

In the step (3), the beaker is stirred at the room temperature of 1200r/min and is stirred at the water bath speed of 900 r/min.

VO loaded on the carbon felt in the step (3)₂The net mass of the nanobelt is 1.58-2.47mg/cm²。

In the step (4), the loading amount of the negative active carbon is 3.20-5.60mg/cm²(ii) a The mass ratio of PVA to LiCl to deionized water is 3-3.5: 6.3-6.56: 30-35; the pressure is 0.1-0.15 MPa; the maintaining time is 10-15 min.

Therefore, the flexible all-solid-state asymmetric supercapacitor obtained by the invention has the following advantages: (1) the electrochemical performance is excellent: the working voltage is stabilized at 1.4V, and the highest energy density reaches 0.715mWh/cm³The highest power density reaches 52.5mW/cm³And the two devices are connected in series to light the LED bulb, so that good practicability is shown. (2) The device is light in weight and good in flexibility, and is expected to provide energy support for portable wearing equipment. (3) The anode and cathode materials are wide in source and low in cost. (4) The preparation of the gel electrolyte and the assembly process of the device are simple, direct, stable, safe and controllable.

Drawings

FIG. 1 is a schematic diagram of experimental process routes and assembled devices taken in examples 1-4 of the present invention.

FIG. 2 shows a pure carbon felt and a CFF @ VO prepared according to example 1 of the present invention₂Scanning electron microscope pictures of the binary composite material in a selected area.

Fig. 3 is a performance test curve of the assembled flexible all-solid-state asymmetric device of example 1 of the present invention.

Fig. 4 is a lighting schematic diagram of the flexible all-solid-state asymmetric device assembled in embodiment 1 of the present invention.

Detailed Description

The technical solution of the present invention is further described below with reference to specific embodiments.

Example 1:

1) cleaning the surface of the carbon felt: preparing 1mol/L HCl and 1mol/L NaOH solution in advance; a piece of commercial carbon felt with a size of 3.5cm x 1.5cm x 3mm (length x width x height) was ultrasonically cleaned with 30mL of HCl solution, 30mL of NaOH solution, 30mL of 95% ethanol solution, and 30mL of deionized water for 15min, and then placed in an oven to be dried for use.

2) Activating the surface of the carbon felt: 3mol/L H is prepared in advance₂SO₄With 3mol/L HNO₃Solution, namely placing the medium carbon felt obtained in the step (1) into a beaker; 60mL of H are weighed in sequence according to the volume ratio of 3:1₂SO₄And 20mL HNO₃Pouring into a beaker; uniformly stirring the beaker at room temperature at the rotating speed of 900r/min for 45 min; then transferring the mixture into a 70 ℃ water bath kettle to continue stirring for 45min at a constant speed of 900 r/min; after stirring, taking out the carbon felt and cleaning the carbon felt with 95% ethanol solution by mass concentration for three times; and finally, drying the carbon felt for 5 hours in a drying oven at the temperature of 65 ℃, and taking out the carbon felt to weigh the carbon felt.

3) Preparing a binary material: 0.6303g C are weighed in turn₂H₂O₄·2H₂O、0.1g CTAB、0.2925gNH₄VO₃Pouring the powder into a beaker into which 30mL of deionized water is added in advance; when the mixed solution is rapidly stirred for 4 hours at the room temperature at the speed of 1200r/min, the color of the mixed solution is changed from dark yellow to green and then to light blue, the mixed solution is transferred to a constant-temperature water bath kettle at the temperature of 75 ℃ to be continuously stirred at the speed of 900r/min, and simultaneously a piece of activated carbon felt is immersed in a beaker for chemical bath deposition; stirring at a constant speed for 60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 ℃ for 3 h. Finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; recording to obtain VO loaded on the carbon felt₂The net mass of the nanobelt is 2.21mg/cm². FIG. 2 shows the pure carbon felt and CFF @ VO in this embodiment₂VO can be seen from SEM picture of binary composite material₂The nanobelts successfully grow on the surface of the carbon felt, and are uniformly distributed and uniform in size.

4) Preparing an all-solid-state supercapacitor: the loading capacity of the cathode active carbon is calculated to be 3.76mg/cm according to the charge conservation law of the anode and the cathode²And coating on the carbon felt according to the loading amount. Then 3g of PVA, 6.3g of LiCl and 30mL of deionized water are weighed to prepare PVA/LiCl gel electrolyte; then respectively immersing the positive electrode and the negative electrode into electrolyte for soaking for 10min, taking out the positive electrode and the negative electrode, and adding a diaphragm between the two electrodes; wrapping a layer of plastic film outside; and finally, maintaining the device under the pressure of 0.1mPa for 15min to obtain the all-solid-state supercapacitor. FIG. 3 is a performance test chart of the device in this embodiment, which can be calculated to obtain the maximum specific capacitance of 1051mF/cm². Fig. 4 is a lighting diagram of the device in this embodiment, which shows that the device has good practicability.

Example 2:

1) cleaning the surface of the carbon felt: this procedure is the same as in example 1.

2) Activating the surface of the carbon felt: preparing 1mol/L H in advance₂SO₄With 1mol/L HNO₃Solution, other steps are the same as in example 1.

3) Preparing a binary material: 0.6303g C are weighed in turn₂H₂O₄·2H₂O、0.1g CTAB、0.2925gNH₄VO₃Pouring the powder into a beaker into which 30mL of deionized water is added in advance; when the mixed solution is rapidly stirred for 4 hours at the room temperature at the speed of 1200r/min, the color of the mixed solution is changed from dark yellow to green and then to light blue, the mixed solution is transferred to a constant-temperature water bath kettle at the temperature of 75 ℃ to be continuously stirred at the speed of 900r/min, and simultaneously a piece of activated carbon felt is immersed in a beaker for chemical bath deposition; stirring at a constant speed for 60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 ℃ for 3 h. Finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; recording to obtain VO loaded on the carbon felt₂The net mass of the nanobelt is 1.58mg/cm²。

4) Preparing an all-solid-state supercapacitor: according to isThe load of the active carbon of the negative electrode is 4.58mg/cm calculated by the law of conservation of charge of the negative electrode²And coating on the carbon felt according to the loading amount. Then 3g of PVA, 6.3g of LiCl and 30mL of deionized water are weighed to prepare PVA/LiCl gel electrolyte; respectively soaking the anode and the cathode in the electrolyte for 10 min; taking out and adding a diaphragm between the two electrodes; wrapping a layer of plastic film outside; and finally, maintaining the device under the pressure of 0.1mPa for 15min to obtain the all-solid-state supercapacitor. Through calculation, the maximum specific capacitance of the device is 893mF/cm²。

Example 3:

1) cleaning the surface of the carbon felt: this procedure is the same as in example 1.

2) Activating the surface of the carbon felt: preparing 6mol/L H in advance₂SO₄With 6mol/L HNO₃Solution, other steps are the same as in example 1.

3) Preparing a binary material: 0.6303g C are weighed in turn₂H₂O₄·2H₂O、0.1g CTAB、0.2925gNH₄VO₃Pouring the powder into a beaker into which 30mL of deionized water is added in advance; when the mixed solution is rapidly stirred for 4 hours at the room temperature at the speed of 1200r/min, the color of the mixed solution is changed from dark yellow to green and then to light blue, the mixed solution is transferred to a constant-temperature water bath kettle at the temperature of 75 ℃ to be continuously stirred at the speed of 900r/min, and simultaneously a piece of activated carbon felt is immersed in a beaker for chemical bath deposition; stirring at a constant speed for 60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 ℃ for 3 h. Finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; recording to obtain VO loaded on the carbon felt₂The net mass of the nanobelt is 2.47mg/cm²。

4) Preparing an all-solid-state supercapacitor: the loading capacity of the cathode active carbon is calculated to be 3.20mg/cm according to the charge conservation law of the anode and the cathode²And coating on the carbon felt according to the loading amount. Weighing 3g of PVA, 6.3g of LiCl and 30mL of deionized water to prepare PVA/LiCl gel electrolyte, respectively soaking the positive electrode and the negative electrode in the electrolyte for 10min, taking out the electrolyte, adding a diaphragm between the two electrodes, wrapping a plastic film outside the electrolyte, and finally wrapping the wrapped device at 0.1mPaAnd maintaining the pressure for 15min to obtain the all-solid-state supercapacitor. Through calculation, the maximum specific capacitance of the device is 857mF/cm²。

Examples 1-3 to compare the effect of the concentration of the mixed acid on the electrochemical performance of the composite material and the electrochemical performance of the device, it can be seen that H₂SO₄With HNO₃When the concentration of the solution is 3mol/L, the device has the best performance.

Example 4:

1) cleaning the surface of the carbon felt: this procedure is the same as in example 1.

2) Activating the surface of the carbon felt: this procedure is the same as in example 1.

3) Preparing a binary material: 0.6325g C are weighed in turn₂H₂O₄·2H₂O、0.12g CTAB、0.3035gNH₄VO₃Pouring the powder into a beaker into which 30mL of deionized water is added in advance; when the mixed solution is rapidly stirred for 4 hours at the room temperature at the speed of 1200r/min, the color of the mixed solution is changed from dark yellow to green and then to light blue, the mixed solution is transferred to a constant-temperature water bath kettle at the temperature of 75 ℃ to be continuously stirred at the speed of 900r/min, and simultaneously a piece of activated carbon felt is immersed in a beaker for chemical bath deposition; stirring at a constant speed for 60min, taking out the carbon felt, washing with deionized water and 95% ethanol by mass concentration, and transferring into an oven; drying at 65 ℃ for 3 h. Finally, taking out the carbon felt, and weighing the mass of the binary composite electrode material; recording to obtain VO loaded on the carbon felt₂The net mass of the nanobelt is 1.96mg/cm²。

4) Preparing an all-solid-state supercapacitor: the loading capacity of the cathode active carbon is calculated to be 3.64mg/cm according to the charge conservation law of the anode and the cathode²And coating on the carbon felt according to the loading amount. And weighing 3g of PVA, 6.3g of LiCl and 30mL of deionized water to prepare PVA/LiCl gel electrolyte, respectively soaking the positive electrode and the negative electrode in the electrolyte for 10min, taking out the electrolyte, adding a diaphragm between the two electrodes, wrapping a plastic film outside the electrolyte, and finally maintaining the wrapped device under the pressure of 0.1mPa for 15min to obtain the all-solid-state supercapacitor. The maximum specific capacitance of the device is calculated to be 962mF/cm². Indicating C deposited by chemical bath₂H₂O₄·2H₂O、CTAB、NH₄VO₃When the mass exceeds a certain range, VO₂The nanobelts can generate excessive accumulation on the carbon felt, so that a certain inhibiting effect is realized on the release of the binary electrode material and the device performance.