Supercapacitor electrolyte and supercapacitor prepared by supercapacitor electrolyte

Abstract

The present invention discloses a supercapacitor electrolyte. The supercapacitor electrolyte comprises electrolyte salt and a non-aqueous solvent, the electrolyte salt at least comprises one ionic liquid, the non-aqueous solvent at least comprises one fluorinated ether, the viscosity of the fluorinated ether is lower than the viscosity of the ionic liquid, the fluorinated ether is employed as the solvent of the ionic liquid to change the ion transmission behavior of the electrolyte and improve the power features of the supercapacitor, and the fluorinated ether is taken as a flame retardant component to improve fire resistance and safety of the electrolyte. The weak polarity and the low solvability of the fluorinated ether allows lots of solions to exist as in a naked ion mode without a non-solvation mode so that more aperture structures being similar to the dimensions of the naked ions in the electrode materials to be employed, and the distance of a double electrode layer established at an electrode / electrolyte interface is smaller to cause the increasing of the capacitance of the double electrode layer. The present invention further provides a supercapacitor using the supercapacitor electrolyte. The supercapacitor is high in energy density, high power density and good in safety performance.

Description

technical field [0001] The invention belongs to the technical field of new energy, and in particular relates to a supercapacitor electrolyte and a supercapacitor prepared therefrom. Background technique [0002] Supercapacitors have outstanding advantages such as high power density, long cycle life, wide operating temperature range, and environmental protection, but the biggest challenge they face is low energy density. Since the energy density of supercapacitors has a quadratic relationship with voltage, the development of electrolyte systems with wide stable potential windows has significant application value. [0003] Ionic liquids usually have good electrochemical stability and are superior to traditional organic electrolytes (such as Et 4 NBF 4 / AN or PC), suitable for application in supercapacitors to increase energy density. However, the use of ionic liquids alone has disadvantages such as high viscosity, low conductivity, and high price. For this reason, a common...

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Problems solved by technology

[0004] Mixing ionic liquids with conventional nitrile or ester organic solvents can improve the ion transport properties of the electrolyte, reduce the amount of ionic liquid, and reduce the cost of the electrolyte, but most of these solvents are flammable, which is not conducive to the safety performance of supercapacitors

Moreover, these solvents usually have a strong solvating ability, which forms an outer coating on anions and cations, increases the ionic radius, and affects the penetration of ions in the microporous structure, resulting in an unsatisfactory performance of the energy density of the supercapacitor.

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