A supercapacitor paper and a method of making the same

Abstract

The application relates to a super capacitor paper and a preparation method thereof. The super capacitor paper comprises a base material, the base material is prepared by using Tencel fiber papermaking, a chemical fiber layer is arranged on the surface of the base material through electrostatic spinning, the thickness of the base material is 15-70 mu m, and the material of the chemical fiber layer is selected from electrostatic spinning materials, and the thickness of the chemical fiber layer is 0.1-20 mu m. The chemical fiber layer is arranged on the base material prepared by using Tencel fiber papermaking through electrostatic spinning, the strength of the super capacitor paper is solved, the aperture of the chemical fiber layer is small and uniform, the porosity is high, and the balance between high power and long pressure retention can be considered.

Description

TECHNICAL FIELD

[0001] The present application relates to a supercapacitor paper and a preparation method thereof. BACKGROUND

[0002] Electrolytic capacitor is one of the most important basic electronic components in electronic engineering. In addition to the filtering, coupling and bypass functions in electronic circuits, it also plays a special role in special circuits such as correction circuits, power supply circuits and AC motor starting circuits. It is widely used in military, civilian communication equipment, audio-visual systems, control appliances and electronic instruments and other fields. Electrolytic capacitor paper is a gasket material for adsorbing electrolyte in electrolytic capacitor, and its performance directly affects the quality of electrolytic capacitor.

[0003] With the rapid development of electronic technology, electrolytic capacitors are rapidly developing towards miniaturization, high quality, high reliability and long life. Correspondingly, higher requirements are put forward for electrolytic capacitor paper, and the development of new high-grade electrolytic capacitors often depends on the development of new electrolytic capacitor paper. Double-layer capacitor, also known as supercapacitor, is a new type of power electronic component that has emerged in recent years with the breakthrough of material science. It fills the gap between ordinary capacitors and batteries in specific energy and specific power, has a capacity of up to thousands of farads, and an instantaneous discharge current of thousands of amperes. In short, it has the capacity of a battery and the rapid charging and discharging performance of a capacitor, and also has the characteristics of safety and reliability, wide application range. It is a breakthrough component for improving and solving the power performance of electronic devices, and it will not pollute the environment like chemical batteries or accumulators. Supercapacitors have great application value and market potential in automobiles (especially electric vehicles, hybrid fuel vehicles and special heavy vehicles), power, railways, communications, national defense industry (especially missile launch and communication), consumer electronics and other fields. It is widely concerned by countries around the world. It has a long cycle life, usually in the order of millions of times, while the cycle life of the lithium battery we commonly use is less than 1,000 times. Due to the superior cycle life of supercapacitors, they are often made into maintenance-free products in the consumer market. Due to the super large capacity characteristics of supercapacitors, many developed countries use them in military equipment, such as the United States, which first used the capacitors in heavy trucks, armored personnel carriers and tanks to ensure the rapid and safe starting of vehicles in low temperature conditions. The supercapacitor paper is one of the core raw materials of the supercapacitor.

[0004] Chinese invention patent (publication number: CN101696558A, publication date: 2010-04-21) discloses a kind of super electrolytic capacitor paper, which is made of pineapple hemp fiber and Tencel fiber papermaking, pineapple hemp fiber is 10-80% by weight, Tencel fiber is 20-90%. The super electrolytic capacitor paper of the patent has low tightness, good strength, small and uniform aperture, low tightness makes its loss low, does not increase the internal resistance of super capacitor, good strength makes it suitable for super capacitor processing, small aperture will make the leakage current of super capacitor small, make it suitable for energy storage, suitable for use in super capacitor.

[0005] Chinese invention patent (publication number: CN108221487A, publication date: 2018-06-29) discloses a kind of low internal resistance super electrolytic capacitor paper, which is made of Tencel fiber and superfine chemical fiber, Tencel fiber is 10-95% by weight, chemical fiber is 5-90%; The chemical fiber used includes one or more of polyester fiber, polyolefin fiber, polyamide fiber, polyimide fiber, polyacrylonitrile fiber, polyvinyl alcohol fiber and spandex fiber. The patent obtains low internal resistance super electrolytic capacitor paper by adding chemical fiber to Tencel pulp, and has good strength, good water absorption and low internal resistance, and the internal resistance can be reduced by more than 0.3Ω.

[0006] The above-mentioned patents use part of plant fibers and superfine chemical fibers, which have high strength, but plant fibers and superfine chemical fibers cannot be nanometerized, and the super electrolytic capacitor paper made of them has the biggest feature of large leakage current, and the energy storage performance of super capacitor is not good, especially in the use of intelligent three meters, the shortcomings are obvious. SUMMARY

[0007] To solve the defects in the above background art, a super capacitor paper suitable for super capacitor is provided, which has a chemical fiber layer on the Tencel fiber papermaking substrate by electrospinning, solving the problem of large leakage current of the papermaking type super capacitor paper, and the chemical fiber layer has smaller and more uniform aperture, high porosity and convenient thickness design, balancing high power and long pressure retention.

[0008] To achieve the above-mentioned purposes, the following technical solutions are adopted in the present application:

[0009] A supercapacitor paper, comprising a substrate, the substrate is made of Tencel fiber papermaking, the surface of the substrate is provided with a chemical fiber layer by electrospinning, the thickness of the substrate is 15-70 µm, below 15 µm, the paper sheet may have a pinhole, carbon particles may penetrate the paper sheet into the other side, and it is very easy to pierce the very thin and extremely small strength electrostatic spinning layer. Higher than 70 µm, the ion passing time through the diaphragm is longer, affecting the maximum advantage of the double-layer capacitor: high power density. The material of the chemical fiber layer is selected from one or more of polypropylene, polyethylene, polyester, polyether, polyacrylonitrile, polyvinyl alcohol, polyamide and polyimide.

[0010] As preferred, the material of the chemical fiber layer is selected from one or more of polypropylene, polyethylene, polyester, polyether, polyacrylonitrile, polyvinyl alcohol, polyamide and polyimide.

[0011] The thickness of the chemical fiber layer is 0.5-5 µm.

[0012] As preferred, the substrate is selected from 100% Tencel fiber; or, the substrate is selected from 20-60% hemp fiber and 40-80% Tencel fiber.

[0013] As preferred, the thickness of the substrate is 20-60 µm; and more preferably, the thickness of the substrate is 25-55 µm.

[0014] Further, the application discloses a preparation method of the supercapacitor paper.

[0015] 1) pulp the Tencel fiber to obtain a substrate;

[0016] 2) dissolve the chemical fiber material in a selected solvent, and adjust the concentration to 15-25% w / v;

[0017] 3) set the chemical fiber spinning on the surface of the substrate by electrospinning.

[0018] As preferred, the step 1) is to pulp the Tencel fiber to 90-95 0 SR, and to make paper with a basis weight of 10-25 g / m 2 .

[0019] As preferred, the solvent used in the step 1) and step 2) is one or more of methanol, ethanol, toluene, dimethylformamide, dimethyl sulfoxide and ethyl acetate.

[0020] As preferred, the parameters of the electrospinning are set as follows:

[0021] 1) voltage: set to 15-25 kilovolts;

[0022] 2) Distance between nozzle and substrate: controlled between 15-20 cm;

[0023] 3) Solution feeding rate: controlled between 0.5-1.0 mL / h;

[0024] 4) Nozzle travel speed: 100-200 mm / s;

[0025] 5) Substrate speed: using a rotating drum, speed set to 1000-2000 rpm.

[0026] The present application, due to the adoption of the above technical solutions, has a chemical fiber layer on the surface of the substrate through electrospinning, which has good strength, small and uniform pore size, high porosity, and is suitable for use in supercapacitors. Good strength makes it suitable for supercapacitor processing, small pore size will make the leakage current of the supercapacitor small, making it suitable for energy storage, high porosity allows a large number of ions to pass through in a short time, and the high power density performance of the supercapacitor is realized. This new type of double-layer capacitor paper can balance between high power and long pressure retention. If the designed double-layer capacitor requires large current discharge, the spinning layer is thin, and the high porosity is maintained as much as possible, and a little leakage current is sacrificed. For example, the port machinery requires such a double-layer capacitor. When the port machinery is working, the instantaneous power required to lift the container is very large, but the work of moving the container is not large, and a small motor can meet the requirements. After lifting the container, the double-layer capacitor is charged to prepare for lifting the next container. At this time, the double-layer capacitor needs to discharge a large current. If the designed double-layer capacitor requires long time to maintain an electric state, i.e. requires a small leakage current as much as possible, then the spinning layer is thickened to reduce the leakage current as much as possible to prolong the time of the capacitor in the electric state. For example, the intelligent three-meter application is an example of this application. The required current is not large, but it needs to be powered for a long time to save data. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a cross-sectional electron microscope photo of the embodiment 3 of the present application.

[0028] Figure 2 It is a cross-sectional electron microscope photo of the embodiment 3 of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0030] Reference Example 1: Tencel fiber is beaten to 92 0SR, using a Fourdrinier paper machine, to make a capacitor paper with a basis weight of 20 g / m 2 , thickness of 40 pm.

[0031] Reference Example 2: Pineapple pulp beaten to 72°SR and Tencel fiber beaten to 88°SR, in a 4 to 6 weight ratio, using a Fourdrinier paper machine, to make a capacitor paper with a basis weight of 20 g / m 2 , thickness of 40 pm.

[0032] Example 1 : Using the capacitor paper in Reference Example 1 as a substrate, electrospinning was performed using polyamide as the electrospinning material, with the electrospinning spray speed and substrate movement speed controlled, and the thickness of the spun layer being 0.1 pm;

[0033] The polyamide was dissolved in ethanol, with the concentration adjusted to 20% w / v.

[0034] The electrospinning parameters were set as follows:

[0035] 1) Voltage: set to 20 kilovolts;

[0036] 2) Distance from nozzle to substrate: controlled to be between 20 centimeters;

[0037] 3) Solution feed rate: controlled to be 0.8 mL / h;

[0038] 4) Nozzle travel speed: 150 mm / s;

[0039] 5) Substrate speed: set to 1200 rpm.

[0040] Example 2: Using the capacitor paper in Reference Example 1 as a substrate, electrospinning was performed using polyamide as the electrospinning material, with the electrospinning spray speed and substrate movement speed controlled, and the thickness of the spun layer being 0.5 pm; the electrospinning method referred to Example 1.

[0041] Example 3: Using the capacitor paper in Reference Example 1 as a substrate, electrospinning was performed using polyamide as the electrospinning material, with the electrospinning spray speed and substrate movement speed controlled, and the thickness of the spun layer being 2.0 pm; the electrospinning method referred to Example 1.

[0042] Example 4: Using the capacitor paper in Reference Example 1 as a substrate, electrospinning was performed using polyamide as the electrospinning material, with the electrospinning spray speed and substrate movement speed controlled, and the thickness of the spun layer being 5.0 pm; the electrospinning method referred to Example 1.

[0043] Example 5: Using the capacitor paper in Reference Example 1 as a substrate, electrospinning was performed using polyamide as the electrospinning material, with the electrospinning spray speed and substrate movement speed controlled, and the thickness of the spun layer being 20.0 pm; the electrospinning method referred to Example 1.

[0044] Example 6: Using the capacitor paper in Reference Example 2 as the base material, electrospinning is performed, the electrospinning material is polyamide, the spray speed and base material moving speed of electrospinning are controlled, the thickness of the spinning layer is 2.0 μm; the electrospinning method refers to Example 1.

[0045] Example 7: Using the capacitor paper in Reference Example 1 as the base material, electrospinning is performed, the electrospinning material is polyester, the spray speed and base material moving speed of electrospinning are controlled, the thickness of the spinning layer is 2.0 μm; the electrospinning method refers to Example 1.

[0046] Comparative Example 1: A Tencel fiber with a beating degree of 85°SR and a microfine polyester fiber with a specification of 0.3 dtex*3 mm are used in a weight ratio of 6:4, and a cylinder paper machine is used for papermaking. The method is described in Chinese Invention Patent (Publication No. CN108221487A, Publication Date: 2018-06-29).

[0047] Comparative Example 2: A Tencel fiber with a beating degree of 85°SR and a microfine polyester fiber are used in a weight ratio of 6:4, and a cylinder paper machine is used for papermaking. The method is described in Chinese Invention Patent (Publication No. CN108221487A, Publication Date: 2018-06-29).

[0048] The base material paper obtained in the above comparative examples, examples and comparative examples is made into a double-layer capacitor with a composite paper, the capacitor is a laminated type, the capacitor specification is 22*45, and the design capacity is 100 F. The initial capacity, resistance, and resistance value and pressure retention value at room temperature 8 and 24 hours of the capacitor are detected.

[0049] The detection data is as follows:

[0050]

[0051] The above describes the embodiments of the present application, and through the above description of the disclosed embodiments, those skilled in the art can implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A supercapacitor paper comprising a substrate, said substrate being made by papermaking from fibers, characterized in that, The surface of the substrate is provided with a chemical fiber layer by electrospinning, the substrate thickness is 15-70 µm, the substrate is selected from 100% Tencel fiber; or, the substrate is selected from 20-60% hemp fiber and 40-80% Tencel fiber; the material of the chemical fiber layer is selected from electrospinnable materials, and the thickness is 0.5-2.0 µm; the material of the chemical fiber layer is selected from polyester or polyamide; The parameters of electrospinning are as follows: 1) Voltage: set to 15-25 kilovolts; 2) Distance from nozzle to substrate: controlled between 15-20 centimeters; 3) Solution feed rate: controlled at 0.5-1.0 mL / h; 4) Nozzle travel speed: 100-200 mm / s; 5) Substrate speed: set to 1000-2000 rpm.

2. The supercapacitor paper according to claim 1, wherein, The substrate thickness is 20-60 µm.

3. The supercapacitor paper according to claim 1, wherein The substrate thickness is 25-55 µm.

4. The preparation method of the supercapacitor paper according to any one of claims 1-3, characterized in that, 1) The substrate is selected from 100% Tencel fiber, the Tencel fiber is beaten, and the substrate is obtained by papermaking; 2) The solvent is selected to dissolve the chemical fiber material, and the concentration is adjusted to 15-25% w / v; 3) The chemical fiber is spun on the surface of the substrate by electrospinning.

5. The preparation method according to claim 4, characterized in that, Step 1) Pulping of Tencel fibers to 90-95 0 SR, sheeted to basis weight 10-25 g / m 2 .

6. The preparation method according to claim 4, characterized in that, The solvent used in step 1) in step 2) is one or more of the following: methanol, ethanol, toluene, dimethylformamide, dimethyl sulfoxide, and ethyl acetate.

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