The Preparation And Electrochemical Capacitance Properties Of High Specific Surface Area Viscose-Based ACF

Viscose-based Activated Carbon Fiber is a kind of new fuction material used in many fields, which has huge specific surface area and appropriate porous structure.The commercial viscose-based activated carbon fiber with the BET surface of1411m2/g were reactivated by KOH at different temperature and alkali/fiber ratio. A series of products with high BET surface were gained.The adsorption performance and porous structure were investigated by nitrogen adsorption isotherm at low temperature(77K) on the base of BET and DFT.The result shows that the specific surface area based on BET, the pores size distribution and the pore structure of VACF vary depending activating conditions. At850℃, the specific surface area based on BET of VACF first decreased with increasing alkali/fiber ratio.But when alkali/fiber ratio exceeds3, the specific surface area increased to a peak,3144.6m2/g at850℃,which is higher than123%for raw material,then falls down with increasing alkali/fiber ratio.VACF activated by KOH was prepared for electrode and the characteristics for electrochemical capacitance of VACF was tested. At700℃, the characteristics for electrochemical capacitance of VACF activated by KOH dependences of alkali/fiber ratio is presented.The specific capacitance of VACF increased with increasing alkali/fiber ratio basically. The specific capacitance of the VACF activated at alkali/fiber ratio=7and700℃reached228F/g.The nanotubes were activated by KOH at alkali/fiber ratio up to8and at850℃. The specific surface area based on BET, the pores size distribution and the pore volume of the activated nanotubes(ACNT) were tested by the way of nitrogen adsorption isotherm at low temperature(77K). For ACNT, the BET surface area is274m2/g and the total pore volume is0.396cm3/g. The characteristics for electrochemical capacitance of ACNT were studied. The results shows that the specific capacitance is very low.In-situ encapsulation of commercial VACF by polyaniline was carried out by polymerization of aniline and the PANI/VACF composites were prepared. The PANI/VACF composites were prepared for EDLC and the characteristics for electrochemical capacitance of PANI/VACF composites were researched.With33.4%(wt) of PANI in composite, the specific capacitance is240F/g,which is higher than85%for VACF.