Pore Structure Control And Electrochemistry Properties Of Hypercoals-Based Activated Carbon

Electric Double Layer Capacitor?EDLC?is a new energy storage device.The properties of electrode materials determine the excellent energy storage performance of Capacitor.As activated carbon make up electrode material,its pore diameter distribution,specific surface area and surface functional groups are the three main factors that affect its electrochemical performance.Three activated methods,namely KOH activated method,CO₂ activated method and CO₂-KOH combined activated method,were used to prepare Hypercoals-Based activated carbon with Hypercoals as raw material.The properties of the activated carbon were characterized by N₂ isothermal adsorption and desorption method,XRD,FT-IR and SEM.By comparing the properties of activated carbon which were prepared by the three activated methods,the evolution rules of pore structure were analyzed,and at the same time,the importance of pore distribution in the range of 0.5?1.5 nm to the improvement of electrochemical performance was proposed.It was found that the evolution of pore structure is closely related to the change of microcrystalline structure.When the early activation,it is dominated by random carbon burning and loss.At the same time,the microcrystalline unit participated in the reaction.With the deepened of the reaction,the microcrystalline structure is etched,mainly by pore expansion.The pore size is gradually dominated by > 0.5 nm,and the ultramicropores and mesopores were developed.Under the combined action of CO₂-KOH,carbon materials with micropores concentrated in the range of 0.4?0.6 nm can be regulated.When the activation temperature is 850 oC,the activation time is 150 min,and the CO₂ flow rate is 10 m L/min/g,the ratio surface is as high as 2412.4 m²/g.Compared with the activation of KOH,the pores of activated carbon are more concentrated in the vicinity of 0.5 nm.The low mesopore rate is not conducive to improving the electrochemical properties,the highest specific capacitance is 212.4 F/g.Figure 54;Table 20;Reference 80...