Preparation And Properties Of Carbon/magnganese Oxide Composites

The electrode material of the supercapacitor has both the double layer capacitance and the pseudocapacitance. Pseudocapaciance always present lager capacity in one capacitor, but it tolerate less charge and discharge cycles than double layer capacitance. Although the double layer capacitance contribute less to the capacity, the material appear no reaction in the cycles. As pseudocapacitive material, manganese oxides have high specific capacitance, low cost and low toxicity. Carbon based materials exhibit predominatly static double layer capacitence with very high stability and large surface area. In this paper, three dimensional porous carbon and maganese oxide of different morphologies are prepared. And then, we syntheis porous carbon/maganese oxide composites. By using the high electrical conductivity and high specific surface area of the porous carbon and the high capacitance of manganese oxide, the electrode composites with high capacitance were prepared.In this thesis, three kinds of porous carbon/manganese dioxide composites were prepared by porous carbon as the basic structure. And the electrochemical properties of three kinds of composites were further measured. The graphene oxide was prepared by microwave method and modified oxidation method. Three dimensional graphene gel was prepared by hydrothermal method. The graphene gel and two kinds of structures were compounded by hydrothermal self-assembly method. The capacitance of the three dimensional graphene/manganese oxide nanorods was 75F/g. The quality of the three dimensional graphene/manganese oxide nanoflower is 244F/g. Porous carbon materials are synthesised by carbonizing pig bones. Bone porous carbon/manganese oxide composites are prepared by microwave method. The influence of material composition, reaction time and reaction temperature on the properties of the material is studied. The composite with highest specific capacitance was obtained with a mass ratio of carbon/ potassium permanganate 1:2 at 180℃ for 3min. Pig bone porous carbon/manganese oxide capacitance is 72F/g.