The invention provides a
graphene composite electrode which comprises a
current collector and
electrode active materials arranged on the surface of the
current collector, wherein the
electrode active materials comprise
graphene and
manganese dioxide. The
graphene is in a stratified structure and is arranged on the surface of the
current collector, and the
manganese dioxide is arranged on the surface of the graphene in the stratified structure.
Mass percentage content of the graphene in the
electrode active materials is 80%-90%. In addition, the invention further relates to a preparation method and an application of the graphene
composite electrode. Oxidized graphene and the
manganese dioxide are deposited on the current collector step by step, adhesion agents are not needed, and therefore
equivalent series resistance of the whole electrode is reduced effectively, capacity and
pseudocapacitance of an electric double-layer of the graphene and the manganese dioxide are developed simultaneously, and stability and
conductivity of the electrode are well improved by addition of the graphene. In addition, through the method of electro-deposition, the electrode materials are directly deposited on an electrode plate, a complex
coating process is saved, the process is simple, and time is short.