Preparation method of winding type super capacitor

Abstract

The invention provides a preparation method of a winding type super capacitor, which comprises the following steps: 1) selecting the direct growth method for preparing a carbon nanotube thin film as an electrode material; 2) cutting the carbon nanotube thin film into a plurality of carbon nanotube thin film small pieces; 3) flatly laying a long strip-shaped separator film in a volatile organic solvent; 4) sequentially flatly laying the plurality of the carbon nanotube thin film small pieces on the separator film in a head-to-tail connection manner till the organic solvent on the separator film which is laid on the carbon nanotube thin film is completely volatilized; and 5) winding and packaging the separator film and obtaining the winding type super capacitor. The invention firstly successfully prepares the winding type super capacitor with a carbon nanotube thin film electrode and can greatly improve the electrical conductivity of the winding type super capacitor, reduce the equivalent series resistance of the super capacitor, further improve the energy and the power density of the carbon nanotube thin film winding type super capacitor and show good power characteristic and current response.

Description

technical field [0001] This embodiment relates to the technical field of electrochemistry, and specifically, the present invention relates to a winding supercapacitor and a preparation method thereof. Background technique [0002] Supercapacitors, also known as electrochemical capacitors, are a new type of energy storage device whose performance is between traditional capacitors and batteries, and has the characteristics of high specific energy of batteries and high specific power of traditional capacitors. Its capacity can reach farad level or even thousands of farads, its mass specific capacitance or volume specific capacitance is 20 to 200 times that of traditional capacitors, and its energy density is 10 to 100 times that of traditional capacitors. At the same time, the power density of supercapacitors is about 10 times higher than that of batteries, and the cycle life is also better than that of batteries, with the number of cycles up to 106. In addition, supercapacito...

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Problems solved by technology

Its defects include: 1. The preparation of activated carbon fiber cloth is relatively complicated, and its electrical conductivity is low. Before it is used as an electrode, a layer of aluminum film must be deposited on its surface to improve its electrical conductivity, and the existence of aluminum film will lead to inorganic Electrolytes such as sulfuric acid solutions will not work

2. The equivalent series resistance (ESR) of the activated carbon fiber cloth supercapacitor is relatively large, which leads to the low power density of the activated carbon fiber cloth

[0006] ①For carbon nanotube polymer film electrodes, the addition of polymer will reduce the conductivity and porosity of carbon nanotube electrodes, which will have an adverse effect on the transfer of charges in the electrode and the diffusion of ions in the electrolyte in the electrode gap. , leading to a decrease in the power density of the supercapacitor, and the carbon nanotube polymer film must use a metal substrate as a current collector to collect and transfer charges. The use of a metal substrate will increase the weight of the capacitor and affect its actual use; in addition, carbon nanotubes The preparation of polymer film electrodes is complicated, the thickness controllability is poor, and the specific capacitance of carbon nanotube polymer supercapacitor is relatively small. Although the specific capacitance can be improved by activating the polymer of carbon nanotubes, the activation needs to be carried out at high temperature. Therefore, many conductive substrates that are not resistant to high temperatures cannot be used

However, the binding force between the carbon nanotube film and the substrate is relatively small. If the substrate and the carbon nanotube film are curled together, the carbon nanotube film will be easily detached from the substrate.

In addition, the poor flexibility and foldability of the substrate makes it difficult for the carbon nanotube film on the substrate to be directly used in the preparation of wound supercapacitors.

[0008] To sum up, the winding supercapacitor can accommodate large-area electrodes to increase its capacitance, and can be used as a high-capacity, high-power pulse power supply. However, the electrode material needs to be soft, foldable and not easy to fall off. Limiting the application of thin-film electrode materials with higher conductivity and porosity

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