Low-temperature flame-retardant organic electrolyte for electric double-layer capacitor and preparation method

Abstract

The invention provides a low-temperature flame-retardant organic electrolyte for an electric double-layer capacitor and a preparation method. The low-temperature flame-retardant organic electrolyte comprises an electrolyte and an organic solvent. The organic solvent comprises a main solvent, a low-temperature cosolvent and a flame-retardant additive. The electrolyte is quaternary ammonium salt, the main solvent is acetonitrile, and the low-temperature cosolvent isone or a combination of more than one of carbonic ester, gamma-butyrolactone, propionate and 1, 3-dioxolane, and the flame-retardant additive is phosphate ester. The electric double-layer capacitor has very excellent low-temperature performance, and the specific discharge capacity of the electric double-layer capacitor at -60 DEG C reaches at least 65%, even up to 80%, of the specific discharge capacity of the electric double-layer capacitor at 25 DEG C. Meanwhile, due to the use of the flame retardant, the electrolyte has good safety performance, the low-temperature flame-retardant organic electrolyte for the electric double-layer capacitor does not have obvious combustion byproducts through a combustion experiment test, and meanwhile, the self-extinguishing time of the electrolyte is halved compared with that of an electrolyte without the flame-retardant additive.

Description

technical field [0001] The invention belongs to the technical field of electric double-layer capacitors, in particular to a low-temperature flame-retardant organic electrolyte for electric double-layer capacitors. Background technique [0002] Electric double layer capacitor is a new type of energy storage device between traditional capacitors and batteries. Generally, activated carbon materials with large specific surface area are used as electrodes, relying on the solid / liquid interface electric double layer generated by polarizable electrodes / electrolyte. To store charge, it has a Farad-level capacitance. Electric double layer capacitors have higher energy density than traditional capacitors, higher power density than secondary batteries, and have the advantages of maintenance-free, high charge and discharge efficiency, long cycle life and wide temperature range. It can be used It can be used as a power auxiliary device in the occasion where high-power discharge is requi...

AI Technical Summary

Problems solved by technology

[0003] At present, electric double layer capacitors widely use organic electrolytes, which have high conductivity and excellent electrode surface wettability, but their thermal stability is not good, easy to leak, poor safety, and the operating temperature range is usually only -40~ Within 60°C, the discharge performance of the device drops sharply at -50°C, and even cannot work, so it cannot meet the working needs in some special temperature environments

Organic electrolytes mostly use aprotic liquids with high dielectric constants as solvents. However, these solvents have low flash points. When supercapacitors are used for rapid charging and discharging, they are prone to heat and fire, which in turn poses a high safety hazard. Application of layer capacitors in military industry, aerospace and other fields

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