Preparation And Electrochemical Performance Of Hypercoals-based Activated Carbon

Electric Double Layer Capacitor(EDLC)is a kind of efficient energy storage devices.The electrode materials used for EDLC are varied,and the coal based activated carbon has been proved to be the main and positive material for electrode.The low rankHypercoals can be applied in capacitor electrode material,which could not only provide a new way for the utilization of low rank coal,but also eliminate the influence of ash on the performance of the capacitor,improving the specific capacitance and specific energy.The effects of the preparation technological on the pore structure and performance of ACs were systematically investigated.By comparing the parameters of Coal-ACs with HPC-ACs,the influence of ash on the pore structure and electrochemical properties of ACs was analyzed.The ACs was prepared by direct activation and carbonizationactivation method.The effects of preparation conditions on the pore structure and electrochemical properties of ACs were investigated by adjusting the AT,At,K/C,Ct and CT.The relationship between specific surface areas,pore size distributions,porosity and the specific capacitance of ACs were discussed.The results show that HPC is a promising raw material for the preparation of electrode material for EDLC.When the HPC was used,the ash content of the ACs was only 0.36%.The specific capacitance and ratio characteristics are higher than Coal-ACs.The ACs with different pore size distribution can be obtained by changing the preparation conditions.The HPC-ACs with specific surface area of 1473 m2/g and pore size in0.58~0.73 nm was achieved with the AT of 600?,At of 1.5 h and the ratio of K/C equals3:1,which shows perfect ratio characteristics and the specific capacitance,specific energy reaches to 373.44 F/g,33.73 Wh/kg.The specific capacitance can still remain above 80% after 1000 cycles.The carbonization process has a certain influence on the specific surface area and pore size distribution of HPC-ACs,however,there was no obvious effect on the improvement of electrochemical performance.