Wide voltage window aqueous electrolyte solution for forming sei film based on physical process, and preparation method and use thereof

Abstract

The present invention discloses a wide voltage window aqueous electrolyte solution for forming an SEI film based on a physical process, including: an additive, an electrolyte and water, where the additive is a long-chain compound having both opposite charge functional groups and having opposite wettability; and the electrolyte is a soluble inorganic salt of an alkali metal. The present invention further provides a method for preparing the aqueous electrolyte solution described above and use of the aqueous electrolyte solution in an electrochemical energy storage device, and the electrochemical energy storage device includes a button supercapacitor, a button ionic capacitor or a pouch supercapacitor. According to the present invention, fan SEI layer is formed at an interface through a pure physical electrostatic adsorption process, a free water content at the interface is precisely reduced to inhibit water decomposition, thus maintaining relatively high ionic conductivity while widening a voltage window, effectively overcoming the problems of low conductivity of a traditional high-voltage aqueous electrolyte solution and consumption of the electrolyte solution for forming an SEI film based on a chemical process, and realizing the high capacity, long cycle life and excellent rate performance in aqueous energy storage devices.