▎ 摘　　要

NOVELTY - Modified electrode has a current collector loaded with carbon-based active material as an electrode, and a polymer film coated on the surface of the electrode. The polymer film is formed by in-situ polymerization of small molecular organic monomers through an electrochemical method. The small molecule organic monomer contains at least one carbon-carbon double bond and a group containing a heteroatom. The group containing heteroatom is at least one chosen from carboxyl group, hydroxyl group, carbonyl group, aldehyde group, sulfonic acid group, phosphoric acid group, nitro group, amino group, mercapto group, amide group, ester group, halogenated group and cyanamide group, preferably at least one chosen from small molecule organic monomers containing carbon-carbon double bonds, alkali metal salts of the small molecular organic monomers containing carbon-carbon double bonds and an alkaline earth metal salts of the small molecular organic monomers containing carbon-carbon double bonds. USE - The modified electrode is used in a high-voltage aqueous supercapacitor (claimed). ADVANTAGE - The modified electrode: utilizes the polymer film, which is ultra-thin and compact structure, can isolate the electrode surface and the electrolyte in the water directly contact can further effectively inhibit the electrolysis of water, so as to improve the voltage window of the electrode; and provides the aqueous high voltage super capacitor, which has improved energy density and power density by greater than 100% respectively 127 Wh to 237kW. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for preparing the modified electrode, involving selecting the current collector loaded with carbon-based active material as the working electrode, selecting the aqueous solution containing small molecular organic monomers as the electrolyte, and using cyclic voltammetry, potentiostatic method or pulse voltage method to excite the carbon-carbon double bond in the small molecule organic monomer containing carbon-carbon double bond to polymerize on the surface of the working electrode to form a polymer film to obtain the modified electrode.