▎ 摘　　要

NOVELTY - A supercapacitor comprises graphene component(s) and metal oxide component(s). The metal oxide component comprises nanowires having a first end attached to the graphene component. USE - Supercapacitor used as electrochemical energy storage device. Uses include but are not limited to small electronics, electrical vehicles, industrial equipment, military devices, or power grid applications. ADVANTAGE - The supercapacitor comprises combination of conductive graphene and high capacitance manganese dioxide. This combination allows for construction of asymmetric aqueous supercapacitors with high voltage. The supercapacitor exhibits excellent conductivity, ability to hold charge and cyclability, and has capacitance of greater than or equal to 20 F/g. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for making an electrochemically active composite material comprising mixing graphene with a metal oxide salt and nonmetallic salts, incubating reactants at a set temperature for a set amount of time, and drying. DESCRIPTION OF DRAWING(S) - The drawing shows a micrograph from transmission electron microscopy illustrating the effect of reaction temperature on structure of graphene/manganese dioxide composite material.