Planar supercapacitor and preparation method thereof

The invention discloses a planar supercapacitor and a preparation method thereof, the planar supercapacitor is composed of a plurality of groups of supercapacitors connected in series, a flexible high-molecular polymer film is used as a substrate and a carbon source, and the film is provided with rows of laser-induced graphene; a conductive current collector is fixed on the flexible high-molecular polymer film, is adjacent to the first laser-induced graphene and the last laser-induced graphene and is in contact with the first laser-induced graphene and the last laser-induced graphene; a gel electrolyte is used as a packaging layer, covers the laser-induced graphene and fills gaps among the laser-induced graphene; the planar supercapacitor forms a series structure in which electron channels and ion channels are alternately connected through laser etching of a packaging layer of intermediate laser-induced graphene, every two laser-induced graphene spaced by the gel electrolyte form a group of supercapacitors, a