Electrolyte and double-electric-layer capacitor

Abstract

The invention belongs to the field of electrochemistry and discloses electrolyte and a double-electric-layer capacitor. The electrolyte comprises hexafluorophosphate ionic liquid and fluorinated alkyl boride in the molar ratio of 1:0.001-1:0.05. The electrolyte for the double-electric-layer capacitor is obtained by mixing the hexafluorophosphate ionic liquid with the fluorinated alkyl boride, and the fluorinated alkyl boride and PF6- can form a complex, so that the dissociation degree of the hexafluorophosphate ionic liquid is increased, conductivity of the electrolyte is increased greatly, and equivalent internal resistance of the double-electric-layer capacitor is lowered greatly. The fluorinated alkyl boride is used as additives, the conductivity of the electrolyte is increased greatly only with the fluorinated alkyl boride accounting for not more than 5% of the total mass of the electrolyte, and if organic solvents are added to increase the conductivity, a great amount of organic liquid is needed to dissolve the hexafluorophosphate ionic liquid low in dissolvability, so that consumption cost of the electrolyte is saved greatly.

Description

technical field [0001] The invention relates to the field of electrochemistry, in particular to an electrolyte. The invention also relates to an electric double layer capacitor using the electrolytic solution. Background technique [0002] Electric double layer capacitor is a new type of energy storage device, which has the advantages of high power density, high cycle life, and fast charge and discharge performance. It is widely used in military fields, mobile communication devices, computers, and hybrid power supplies for electric vehicles. As an important part of the electric double layer capacitor, the electrolyte has a great influence on the storage performance of the electric double layer capacitor, which determines the working voltage range, storage capacity, working temperature and working environment of the capacitor. [0003] Ionic liquids are organic liquid substances composed entirely of ions at or near room temperature. As a new type of electrolyte, the emergen...

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Problems solved by technology

Ionic liquids have good development prospects as the electrolyte of electric double-layer capacitors. However, the capacitance of pure ionic liquids at room temperature is not high, resulting in the equivalent internal resistance of electric double-layer capacitors using pure ionic liquids as electrolytes. Big

Hexafluorophosphonate ionic liquid is currently one of the most commonly used ionic liquid electrolytes because of its easy synthesis and low cost, but its high resistance limits its application as an electrolyte for electric double layer capacitors. The method of organic solvent (acetonitrile, propylene carbonate, 1-butyrolactone) can achieve the purpose of greatly reducing the equivalent internal resistance of the electric double layer capacitor, but it greatly increases the amount of electrolyte in the electric double layer capacitor, thereby increasing the cost

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