Co-pyrolysis Of Hypercoal And Biomass To Prepare Activated Carbon For Electric Double Layer Capacitors

The development of the economy led to energy problem,it promoted the research of energy storage devices.As a new type energy storage device,EDLC attracted more attention.The electrode materials prepared from different raw materials result in various performance.Activated carbon electrode material for EDLC was prepared from lignite,corncob and pine sawdust.Corncob or pine sawdust was added to the hypercoal,then activated with KOH.The structure of activated carbon was characterized by XRD,FT-IR,SEM and BET,and electrochemical properties were tested by GCD,CV and EIS to investigate the differences at different biomass additions.The properties of activated carbon with added different biomass were compared to explore the effection of different biomass components.The results show that adding an appropriate amount of biomass to hypercoal could improve the electrochemical performance of the activated carbon.The optimum preparation conditions for the addition of corncob were:25%of the corncob addition,activated temperature of 750°C,activated time of 90 min,the mass ratio of KOH to raw material was 5,and the S_BETof the activated carbon was 3146.6 m²/g,the pore proportion of 0.5～1.5 nm was 73.52%,the specific capacitance was 359.01 F/g.The optimum preparation conditions for the addition of pine sawdust were:30%of the pine sawdust addition,activated temperature of 750°C,activated time of 90 min,the mass ratio of KOH to raw material was 5,and the S_BETof the activated carbon was 2694.7 m²/g,the pore proportion of 0.5～1.5 nm was 70.76%,the specific capacitance was 321.36 F/g.A comparative study of activated carbon prepared by adding different biomass revealed that more gas and small molecules of volatile matter were generated during the co-activation of hypercoal and biomass.They had a pore-opening and pore-expanding effect on the activated carbon,resulting in the improvement of its electrochemical properties.The addition of biomass with high cellulose and hemicellulose content was more beneficial in improving the electrochemical performance of the activated carbon.In terms of overall percentage,the specific capacitance could reach 300 F/g and the energy density could reach 27 Wh/kg with cellulose hemicellulose content of 15%～25%and lignine of 2%～10%.Figure 64;Table 20;Reference 62...