▎ 摘　　要

NOVELTY - Graphene-coated manganese dioxide composite electrode material comprises graphene and nano manganese dioxide particles. Graphene is coated in the gap of surface of nano manganese dioxide particles. The mass ratio of graphene and nano manganese dioxide particles is 1:(1.25-10). USE - Graphene-coated manganese dioxide composite electrode material is used for supercapacitors. ADVANTAGE - The graphene-coated manganese dioxide composite electrode material has excellent conductivity and stability. The presence of manganese dioxide particles effectively prevents agglomeration of graphene, increasing the specific capacity of electrode material. The electrode material can be prepared by a simple method with high purity and easy control of reaction product. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of graphene-coated manganese dioxide composite electrode material, which involves preparing nano manganese dioxide particles and graphite oxide, preparing graphene oxide dispersion liquid-coated manganese dioxide by ultrasonically dispersing graphite oxide in distilled water in a concentration of 0.5-2 mg/ml and adding nano manganese dioxide particles to the dispersion, adding a reducing agent, heating and stirring to complete reaction, carrying out solid-liquid separation, washing, and drying. The reducing agent is hydrazine hydrate, sodium borohydride, and/or ascorbic acid. The reduction temperature is 80-105 degrees C and the reduction time is 6-24 hours.