High voltage graphene-based electrolyte for aqueous lithium ion capacitor

Abstract

The invention relates to a high voltage graphene-based electrolyte for an aqueous lithium ion capacitor, and belongs to the technical field of the electrolyte. The high voltage graphene-based electrolyte for the aqueous lithium ion capacitor comprises two parts: (1) an aqueous electrolyte component: water and lithium salt are combined to form the aqueous electrolyte, wherein the lithium salt is one or more of lithium difluorosulfonimide, lithium pentafluorophenylimide and lithium difluorophosphate in the mass ratio of 100: 10-99: 30-99, and the total concentration of salt is 3-20 mol / L; (2) anegative electrode protection component: a protective layer with conductive hydrophobic groups is coated on the surface of the negative electrode, and the protective layer is a solid gel electrolyte layer which is one or multiple compounds of conductive electrolyte lithium difluorosulfonimide, lithium pentafluorophenylimide and lithium difluorophosphate in the mass ratio of 100: 10-99: 30-99, thetotal salt concentration is 1-3 mol / L and carbonate organic solvent and polymer monomer. The high voltage graphene-based electrolyte for the aqueous lithium ion capacitor has the advantages of high conductivity, stable existence, safety and reliability, wide application range and the like.

Description

technical field [0001] The invention belongs to the technical field of electrolytes, in particular to an electrolyte for high-voltage graphene-based water-based lithium-ion capacitors. Background technique [0002] Supercapacitor is a very common new energy power system at present. It can be used in a series of fields such as hybrid new energy vehicle power supply, energy storage and frequency modulation power supply. The energy storage and charging and discharging mechanism of supercapacitors that have been commercialized are mainly based on physical Adsorption-desorption is the main method, so the energy density is extremely low, and long-term energy storage is not possible. [0003] The mechanism of lithium-ion capacitors and lithium-ion batteries is similar. The positive electrode generally uses carbon materials such as activated carbon, while the negative electrode generally uses the negative electrode materials of lithium-ion batteries such as graphite and hard carbon....

AI Technical Summary

Problems solved by technology

At present, the lithium-ion capacitors reported in the industry are all organic electrolyte systems. This is mainly because certain lithium dendrites will be generated on the surface of the negative electrode due to polarization during charging and discharging. The dendrites will burn violently, exotherm and even explode when they encounter water. , so the aqueous electrolyte was once considered to be unsuitable for lithium-ion batteries and capacitor systems

There are water capacitor systems reported in domestic and foreign literature, but considering the low decomposition voltage of water, the working voltage is generally below 2.0V.