CN113764200B - A kind of supercapacitor, diaphragm and preparation method thereof - Google Patents

Abstract

The invention discloses a super capacitor, a super capacitor diaphragm and a preparation method, wherein the super capacitor diaphragm is prepared from the following raw materials in percentage by mass: 5-60% of ampullaria gigas shell powder, 12-65% of aluminium oxide, 4-8% of corn starch, 3-8% of silicon dioxide, 3-6% of potassium phosphate, 5-10% of diboron trioxide, 0.5-5% of calcium oxide and 0.5-5% of polyvinyl alcohol. According to the invention, the Pomacea canaliculata shell is used as a raw material to prepare the supercapacitor diaphragm, so that the application of the Pomacea canaliculata shell is realized, the damage of the Pomacea canaliculata to the ecological environment is reduced, the sintering temperature in the diaphragm preparation process is reduced, and the manufacturing cost is further reduced.

Description

A kind of supercapacitor, diaphragm and preparation method thereof

technical field

The invention relates to the technical field of capacitors, in particular to a super capacitor, a diaphragm and a preparation method thereof.

Background technique

With the rapid development of new industries such as new energy vehicles and smart phones, higher requirements have been placed on the performance improvement of energy storage devices. Supercapacitors (SCs) are a new type of energy storage device with fast charge-discharge capability, long cycle life and high safety, which make up for some of the defects of lithium-ion batteries and are the key development target of high-efficiency energy storage devices. . Improving the stability and life of supercapacitors is an important research direction.

Supercapacitors are mainly composed of electrodes, diaphragms, electrolytes and other components. As one of the key materials of supercapacitors, its structure and performance directly affect the specific power, specific capacity and cycle life of supercapacitors. Common diaphragm materials mainly include cellulose paper diaphragm, synthetic polymer diaphragm, electrospinning diaphragm and biological diaphragm. With the wide application of capacitors, how to prepare low-cost and high-performance separators has become an urgent technical problem to be solved.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a supercapacitor, a supercapacitor diaphragm and a preparation method thereof, aiming at solving the problem of the preparation cost of the existing supercapacitor.

The invention provides a supercapacitor diaphragm, which is prepared from the following raw materials by mass percentage: 5-60% Fushou snail shell powder, 12-65% aluminum oxide, 4-8% corn starch, 3-8% Silica, 3-6% potassium phosphate, 5-10% boron trioxide, 0.5-5% calcium oxide and 0.5-5% polyvinyl alcohol.

Further, the Fushou snail shell powder is 100-300 mesh.

Further, the corn starch is 100-150 mesh.

The invention utilizes the shells of the snails abundant in nature as raw materials to prepare the supercapacitor diaphragm, which not only reduces the damage of the snails to the ecological environment, but also greatly excavates the economic value contained in the snails, and reduces the manufacturing cost of the capacitor diaphragm.

In addition, the present invention also provides a method for preparing a supercapacitor diaphragm, comprising the following steps:

S1, the above-mentioned mass percentage is mixed with Fushou snail shell powder, aluminum oxide, cornstarch, silicon dioxide, potassium phosphate, boron trioxide, calcium oxide;

S2, adding the mixed raw materials into the nanometer ball mill and dry ball milling to a powder with an average particle size of 1-10 microns;

S3, mixing the above powder with 0.5-5% polyvinyl alcohol and drying;

S4, pressing the dried raw material and sintering at low temperature to prepare the supercapacitor diaphragm.

Further, described Fushou snail shell powder is obtained by the following method:

S01, put the Fushou snail shell into a 2-5% sodium lauryl sulfate aqueous solution for cleaning and drying to obtain a clean snail shell;

S02, crushing the clean snail shell into shell powder with a pulverizer, and sieving with a 100-300 mesh screen to obtain the Fushou snail shell powder.

Further, the compression molding in step S4 is specifically: compression molding with a press under a pressure of 10-30 MPa, with a thickness of about 1.2 mm.

Further, the low-temperature sintering in step S4 is specifically: low-temperature sintering in an air atmosphere of 350-580° C. for 0.5-5 h.

The main component of the Fushou snail shell is aragonite-type calcium carbonate. Using the characteristics of the Fushou snail shell itself and cooperating with other components, the invention can greatly reduce the temperature in the sintering stage when preparing the supercapacitor diaphragm, and only needs to be in an air atmosphere of 350-580 ° C. The medium and low temperature sintering is sufficient for 0.5-5 hours. The reduction of the sintering temperature means the reduction of energy consumption, which further reduces the manufacturing cost of the capacitor diaphragm.

At the same time, the present invention also provides a supercapacitor, comprising the separator prepared by the above preparation method.

Further, both the positive and negative electrodes of the supercapacitor use carbon nanotube electrodes based on nickel foam.

Further, the preparation method of the carboxyl carbon nanotube electrode includes: weighing 5-30 mg of carboxyl carbon nanotubes with 200-500 μL tetrahydrofuran to dissolve, taking 100 μL of the solution dropwise into 1-10 mg acetylene carbon black for ultrasonic dispersion, adding 10 The 0.01-0.06 mol/L glue prepared from -50 μL of PTFE emulsion was stirred evenly to form a paste, and then pressed onto a nickel foam sheet and vacuum-dried.

The invention adopts the supercapacitor diaphragm prepared by Fushou screw shell, which has good insulation performance, controllable pore structure and morphology, stable chemical properties and high mechanical strength. Tests such as current charging and discharging have verified that the supercapacitor has good energy storage performance stability and long life. After 20,000 cycle tests, the performance remains good.

Description of drawings

1 is a flow chart of a method for preparing a supercapacitor diaphragm in an embodiment of the present invention;

Fig. 2 is the flow chart of the preparation method of Fushou snail shell powder in an embodiment of the present invention;

3 is a CV diagram of a supercapacitor at different scan rates in an embodiment of the present invention;

4 is a test chart of the dependence of the specific capacitance of the supercapacitor on the scan rate in an embodiment of the present invention;

5 is a constant current charge-discharge curve diagram of a supercapacitor under different current densities in an embodiment of the present invention;

6 is a test chart of the dependence of the specific capacitance of the supercapacitor on the current density in an embodiment of the present invention;

7 is a test chart of the dependence of the supercapacitor capacitance retention rate on the number of cycles (current density is 3.60 A g-1) in an embodiment of the present invention;

FIG. 8 is an electrochemical AC impedance spectrogram of the supercapacitor before and after 20,000 cycle life tests at room temperature in an embodiment of the present invention.

Detailed ways

The present invention provides a supercapacitor diaphragm, a preparation method thereof, and a supercapacitor. In order to make the purpose, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The invention provides a supercapacitor diaphragm, which is prepared from the following raw materials by mass percentage: 5-60% Fushou snail shell powder, 12-65% aluminum oxide, 4-8% corn starch, 3-8% Silica, 3-6% potassium phosphate, 5-10% boron trioxide, 0.5-5% calcium oxide and 0.5-5% polyvinyl alcohol.

Preferably, the Fushou snail shell powder is 100-300 mesh.

Preferably, the corn starch is 100-150 mesh.

As shown in Figure 1, the present invention also provides a method for preparing a supercapacitor diaphragm, comprising the following steps:

S1, the above-mentioned mass percentage is mixed with Fushou snail shell powder, aluminum oxide, cornstarch, silicon dioxide, potassium phosphate, boron trioxide, calcium oxide;

S2, adding the mixed raw materials into the nanometer ball mill and dry ball milling to a powder with an average particle size of 1-10 microns;

S3, mixing the above powder with 0.5-5% polyvinyl alcohol and drying;

S4, pressing the dried raw material and sintering at low temperature to prepare the supercapacitor diaphragm.

Preferably, as shown in Figure 2, the Fushou snail shell powder is prepared by the following method:

S01, put the Fushou snail shell into a 2-5% sodium lauryl sulfate aqueous solution for cleaning and drying to obtain a clean snail shell;

S02, crushing the clean snail shell into shell powder with a pulverizer, and sieving with a 100-300 mesh screen to obtain the Fushou snail shell powder.

Preferably, the compression molding in step S4 is specifically: compression molding with a press under a pressure of 10-30 MPa, with a thickness of about 1.2 mm.

Preferably, the low-temperature sintering in step S4 is specifically: low-temperature sintering in an air atmosphere of 350-580° C. for 0.5-5 h.

At the same time, the present invention also provides a supercapacitor, comprising the separator prepared by the above preparation method.

Preferably, both the positive and negative electrodes of the supercapacitor are carboxyl carbon nanotube electrodes based on nickel foam.

Preferably, the preparation method of the carboxyl carbon nanotube electrode comprises: dissolving 5-30 mg of carboxyl carbon nanotubes with 200-500 μL of tetrahydrofuran, dropping 100 μL of the solution into 1-10 mg of acetylene carbon black for ultrasonic dispersion, adding 10 -50 μL of polytetrafluoroethylene emulsion (PTFE, 0.01mg/L) was prepared by mixing 0.01-0.06 mol/L glue to form a paste, and then pressing it on a nickel foam sheet and vacuum-drying it. Preferably, the positive and negative electrodes are prepared by vacuum drying at 80-130 °C for 1-10 h.

In order to verify the performance of the supercapacitor of the present invention, in one embodiment, the capacitor diaphragm made of the positive and negative electrodes and the Fushou screw shell was cut into small pieces of 2 cm × 2 cm, and immersed in a 1.0 mol/L Na ₂ SO ₄ aqueous solution. Wetting in the middle, place the glass slide, positive electrode, capacitor diaphragm, negative electrode and glass slide horizontally from bottom to top in turn, and then wrap and seal the supercapacitor with paraffin film to seal the supercapacitor device F. .

Figure 3 shows the CV diagrams of the device F at different scan rates. It can be seen from the figure that the CV diagrams of the device F are all rectangular or quasi-rectangular, indicating that the devices have good capacitance characteristics. As the scan rate increases, the area of the CV curve gradually increases.

，计算结 果如图4所示。从图4中可以看出随着扫描速率从10，20，50，100至200 mV s-1增加，器件的 比电容随着扫描速率的增加而下降。当扫描速率高达200 mV/s时，比电容为7.4 F g^-1，其倍 率为59.2%，表明其具有高的倍率。 We calculate the specific capacitance of device F from the integral area of Fig. 3, and the calculation formula is

, and the calculation result is shown in Fig. It can be seen from Figure 4 that the specific capacitance of the device decreases with increasing scan rate as scan rate increases from 10, 20, 50, 100 to 200 mV s-1. When the scan rate is as high as 200 mV/s, the specific capacitance is 7.4 F g ^-1 and its magnification is 59.2%, indicating its high magnification.

The charge-discharge curves of device F at different current densities were further studied through constant current charge-discharge tests. As shown in Figure 5, the curves all showed good symmetry and linearity, reflecting excellent supercapacitor performance.

，从图5的放电曲线计算出器件F在不同电流密度下的比电容 值，如图6所示。电流密度依次为0.07，0.18，0.36，0.73，1.80和3.60 A g^-1时，比电容分别为 13.3，12.4，11.6，10.6，8.3和5.4 F g^-1，上述结果表明器件F具有优越的超级电容性能。 Use the formula

, the specific capacitance values of device F at different current densities are calculated from the discharge curves in Figure 5, as shown in Figure 6. When the current densities are 0.07, 0.18, 0.36, 0.73, 1.80 and 3.60 A g ^-1 in turn, the specific capacitances are 13.3, 12.4, 11.6, 10.6, 8.3 and 5.4 F g ^-1 , respectively. Capacitive performance.

In addition to being able to charge and discharge rapidly, cycle life is a key parameter for capacitor performance. When the current density is 3.60 A g-1, the cycle life test of device F is carried out, and the results of 20,000 times of charge and discharge are shown in Fig. 7. The capacitance did not decay after 20,000 cycles, indicating a long service life. In order to further study the internal resistance of device F, electrochemical impedance spectroscopy (EIS) data before and after 20,000 life tests were collected as shown in Figure 8. It can be seen that the two EIS curves basically overlap, indicating that 20,000 cycles Before and after, the internal resistance is basically unchanged. Specifically, the two EIS curves are a small semicircle in the high frequency region, indicating that device F has a very low charge transfer internal resistance. The mid-low frequency region is an upward sloping curve, indicating that device F has ideal capacitive behavior before and after the cycle life test.

To sum up, the present invention adopts the Fushou screw shell to prepare a supercapacitor diaphragm, and the diaphragm has good insulating properties, controllable pore structure and morphology, stable chemical properties and high mechanical strength. After applying it to the supercapacitor device, through electrochemical characterization such as cyclic voltammetry and constant current charge-discharge, it is found that the specific capacitance of device F is 13.3 F g ^-1 when the current density is 0.07 A g ^-1 ; at 3.60 A The cycle life test was carried out at g ^-1 , and the specific capacitance of device F did not decay after 20,000 cycles, indicating that the Fushou screw-shell porous ceramic separator is a supercapacitor separator with excellent performance.

It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (6)

1. a supercapacitor, is characterized in that, comprises the supercapacitor diaphragm that the preparation method of supercapacitor diaphragm makes, the positive and negative poles of described supercapacitor all adopt the carboxyl carbon nanotube electrode that takes nickel foam as substrate, wherein, The supercapacitor diaphragm is prepared from the following raw materials by mass percentage: 5-60% Fushou snail shell powder, 12-65% aluminum oxide, 4-8% corn starch, 3-8% silicon dioxide, 3- 6% potassium phosphate, 5-10% boron trioxide, 0.5-5% calcium oxide and 0.5-5% polyvinyl alcohol; Wherein, the preparation method of the supercapacitor diaphragm comprises the following steps: S1, by the above-mentioned mass percentage by described diaphragm, Fushou snail shell powder, aluminum oxide, corn starch, silicon dioxide, potassium phosphate, boron trioxide, calcium oxide are mixed; S2, adding the above-mentioned mixed raw materials into the nanometer ball mill and dry ball milling to a powder with an average particle size of 1-10 microns; S3, the above-mentioned powder is uniformly mixed with the above-mentioned mass percent polyvinyl alcohol and dried; S4, pressing the dried raw material and sintering at low temperature to prepare the supercapacitor diaphragm. 2. The supercapacitor according to claim 1, wherein the preparation method of the carboxy carbon nanotube electrode comprises: taking 5-30 mg of carboxy carbon nanotubes and dissolving them in 200-500 μL tetrahydrofuran, taking 100 μL of the solution dropwise and adding 1-10mg of acetylene carbon black is ultrasonically dispersed, and 0.01-0.06mol/L glue prepared by adding 10-50μL of polytetrafluoroethylene emulsion is mixed to form a paste, and then pressed on a foam nickel sheet and vacuum-dried. 3 . The supercapacitor according to claim 1 , wherein the Fushou snail shell powder is 100-300 mesh, and the corn starch is 100-150 mesh. 4 . 4 . The supercapacitor according to claim 1 , wherein the compression molding in step S4 is specifically: compression molding with a press under a pressure of 10-30 MPa, with a thickness of 1.2 mm. 5 . 5 . The supercapacitor according to claim 4 , wherein the low-temperature sintering in step S4 is specifically: low-temperature sintering in an air atmosphere of 350-580° C. for 0.5-5 h. 6 . 6. supercapacitor according to claim 1, is characterized in that, described Fushou snail shell powder is made by following method: S01, put the Fushou snail shell into a 2-5% sodium lauryl sulfate aqueous solution for cleaning and drying to obtain a clean snail shell; S02, crushing the clean snail shell into shell powder with a pulverizer, and sieving with a 100-300 mesh screen to obtain the Fushou snail shell powder.

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