A high voltage resistant electrolyte and application thereof in high voltage supercapacitors

Abstract

The invention discloses a high-voltage resistant electrolyte and application thereof in a high-voltage supercapacitors, and belongs to the technical field of electrochemistry. The electrolyte of the present invention comprises an electrolyte formed by mixing a quaternary ammonium salt or a quaternary phosphate salt with a bis (trifluoromethanesulfonyl) imide salt, organic solvents and high voltageadditives, has wider potential window and better electrochemical stability, and are not easy to decompose at high voltage, and are not easy to destroy electrode materials due to side reactions with functional groups on the electrode materials. The application of the high-voltage-resistant electrolyte in the high-voltage supercapacitor of the invention enables the supercapacitor to work stably fora long time under the voltage of 2.7 to 3.2 V, and the working temperature range is wide. 40 to 70 DEG C, and has that advantage of low viscosity, high conductivity, small internal resistance and thelike.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a high-voltage-resistant electrolyte solution and its application in high-voltage supercapacitors. Background technique [0002] A supercapacitor is a new type of energy storage device between batteries and traditional electrostatic capacitors. Supercapacitors have the advantages of high power density, fast charging and discharging, long life, good safety, wide operating temperature and environmental friendliness. Compared with electrochemical batteries, supercapacitors have low energy density and low operating voltage, which greatly limit the practical application range of supercapacitors. Since the calculation formula of the energy density of the supercapacitor is: E=CV 2 / 2, so in order to increase the energy density of the supercapacitor, its capacity C and working voltage V are usually increased. At present, commercialized organic supercapacitors will...

AI Technical Summary

Problems solved by technology

At present, commercialized organic supercapacitors will cause electrochemical decomposition of the electrolyte when it exceeds 3.0V, including the decomposition of trace water contained in the electrolyte and active materials, the catalytic reaction caused by free acid, and the precipitation of oxygen-containing groups. The chemical reaction will produce a large amount of gas, which will increase the pressure in the capacitor, reduce the electrochemical performance, and eventually lead to the failure of the capacitor

[0003] The electrolyte has a great influence on the performance of the supercapacitor, and the compatibility between the electrolyte and the electrode material is the determinant of the working voltage of the supercapacitor: the patent with the publication number CN104134551A discloses that a cation is N-methyl-1,4-diazo Heterobicyclo[2.2.2]octyl ammonium, N,N-dimethyl-1,4-diazabicyclo[2.2.2]octyl ammonium, N-methyl-1-azabicyclo[ 2.2.2] Octyl ammonium, the anions are tetrafluoroborate, hexafluorophosphate, bis(trifluoromethylamido)imide, bis(trifluoromethylamido)methyl and perfluoroalkylsulfonyl, Although it has a certain high-voltage resistance, the synthesis of the substance is difficult and the production cost is high. There are no reports of related compounds on the market, and the supercapacitor made with the related electrolyte has a short service life at a working voltage of 3.2V; The Chinese patent in the publication number CN101809693B mentions that in Et 4 BF 4 Add various acid scavenging agents in the acetonitrile solution to slow down the pressure rise inside the capacitor to increase the working voltage of the supercapacitor, but with the prolongation of the service time, the performance of the capacitor deteriorates significantly; the Chinese patent in the publication number CN106449162A mentions the use of The high-voltage resistant electrolyte formulated with dissociative salt and high-voltage stabilizer, used in conjunction with the fabricated electrode, showed good performance at a working voltage of 3.0V, but the use at a working voltage of 3.2V was not reported

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