Fabrication Of Carbonaceous Nanocomposites And Its Application For Supercapacitor

Energy crisis has been become a serious issue in recent decades, it is an ugent task to develop better energy storage materials. Supercapacitor is a novel electrochemical energy storage device based on the interface electric double layer theory of German physicist Helmholtz, which has attarcted increasingly attention due to its high power density, long life, wide operating range and other excellent properties. Its working principle is making use of an electric double layer consisting of the solid electrode and the electrolyte. Therefore, electrode material is the key factor for the entire apparatus, and the development of new electrode materials is particularly important. The electrode material mainly including carbon material, metal oxide and conductive polymer. For supercapacitor, carbon material has good stability, but the capacitance value is relatively low. In contrast, metal oxide has high capacitance value, but poor stability. In this thesis, the nanocomposite of carbon materials and metal oxide has been synthsized and studed its supercapacitor properties, mainly including:(1) Preparation of graphene based nano-composite by controlling the proportion of the graphene oxide (GO) and the cobalt chloride salt. The electrochemical property of the nano-composite has been studied and obtained high performance supercapacitors with the capacitance of70F/g, under a current of5mA. After the charge and discharge frequency1000times, the capacitor value can still reach86%of the initial value, showing a good cycle stability.(2) The complex of alkali cobalt carbonate and GO was prepared using a simple hydrothermal method. The three-electrode electrochemical mearesurement shows that the capacitance value of this composite can reach187F/g.(3) With the existence of mesoporous carbon nanorods (meso-CNRs), uniform Co3O4nanocubes in size of50nm were synthesized by a novel one step hydrothermal method. The resulting nanocubes have controllable shape, uniform particle size, and high crystallinity. The resulting nanocubes demonstrate remarkable performance in supercapacitor application due to porous structure endows fast ion and electron transfer.