Method for increasing specific capacitance of graphene-based supercapacitor

Abstract

The invention relates to a method for increasing the specific capacitance of a graphene-based supercapacitor. An electrode of a supercapacitor is prepared from graphene, and the theoretical capacitance can be up to 550F / g. However, because of factors such as material properties and preparation techniques, generally the contained specific capacitance is within 150-300F / g. According to the method, sodium chloride and urea are doped into a graphene oxide solution of a liquid crystal state for the first time, a film is prepared from the solution by using a scraper in a coating manner, and thus a film obtained after hydrothermal reduction is adopted as the electrode of the supercapacitor. Due to added substances, graphitization stacking of graphene layers can be prevented and nitrogen doping can be achieved in the hydrothermal reduction process of the graphene film, so that the specific capacitance can be greater than 400F / g when aqueous electrolyte is used, and is at a relatively high level. The electrode of the graphene-based supercapacitor prepared by using the method is uniform in thickness, good in operability and simple to operate, in addition, the used raw materials are cheap, and the method is green. The process of the scraper coating method for preparing the film can be further improved, and can be applied to industrial production.

Description

technical field [0001] The invention belongs to the field of graphene-based supercapacitors, and the main content is a preparation technology of an energy storage electrode, which can realize relatively high specific capacitance. By adding other chemical substances to the aqueous solution of liquid crystal graphene oxide, the graphene in the film obtained by hydrothermal reduction after doctor blade coating can not only suppress the graphitization accumulation between the sheets in the way of bending and wrinkling, but also realize Nitrogen doping improves the charge storage capacity, and the specific capacitance exceeds 400F / g, which provides a technical route for preparing supercapacitors with high energy density. Background technique [0002] Supercapacitors are also commonly called electrochemical capacitors and electric double layer supercapacitors. It is a new type of energy storage device between batteries and capacitors. It has the characteristics of high power dens...

AI Technical Summary

Problems solved by technology

The general result is lower specific capacitance and lower capacitance retention

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