Electrolyte and electrical double-layer capacitor

Abstract

The invention belongs to the field of electrochemistry, and discloses an electrolyte and a capacitor using the electrolyte. The electrolyte comprises hexafluorophosphate ionic liquid and an aza-ether compound with a molar ratio of 1:(0.001-1):0.05. The invention further provides the electrolyte used for the double-layer capacitor, the electrolyte is formed by mixing the hexafluorophosphate ionic liquid with the aza-ether compound, the aza-ether compound can form a coordination compound with PF6-, and accordingly dissociation level of the hexafluorophosphate ionic liquid is increased, conductivity of the hexafluorophosphate ionic liquid is greatly increased, and equivalent internal resistance of the double-layer capacitor is greatly lowered. The aza-ether compound is used as addictive, the conductivity of the hexafluorophosphate ionic liquid can be improved greatly by only needing less than 5% of the total mass of the hexafluorophosphate ionic liquid, the conductivity of the hexafluorophosphate ionic liquid is improved by adding organic solvent so that the hexafluorophosphate ionic liquid which is low in solubility and is dissolved by a great quantity of organic liquid is dissolved, and usage cost of the electrolyte is greatly saved.

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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