Synthesis Of Porous Carbons For Supercapacitors With ZnO As Template Coupled With KOH Activation

Supercapacitors have attracted extensive attention as potential and environmentally friendly devices for maintaining power owing to their rapid charge and discharge, long cycle life and high power density. Electrode materials with high specific surface area, appropriate pore and good conductivity are the key to improve electrochemical performances of supercapacitors. In this paper, porous carbons?PCs?were prepared by ZnO template coupled with KOH activation. PCs were characterized by field emission scanning electron microscope and transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and N2adsorption/desorption techniques. The electrochemical performances of PCs were tested by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The main conclusions are as follows.PC/nickel foams?PC/NFs? were prepared from coal tar pitch?CTP? by Zn?CH3COO?2·2H2O template strategy coupled with KOH activation at 600 W of microwave power based on nickel foam. Under optimum conditions, the PC/NF_3-18-10 made with the masses of CTP, Zn?CH3COO?2·2H2O, KOH at 3 g, 18 g, 10 g in argon atmosphere is interconnected carbon sheets growing along with nickel foam, which shorten ions transport distance and improve electric conductivity. The specific capacitance of PC/NF_3-18-10 reaches 3322 mF/cm² at 0.5 mA/cm² current density in 6M KOH electrolyte, and remains 2135 mF/cm² when the current density is increased ca. one thousand times.PCs were prepared from coal tar?CT? by nano-ZnO template strategy coupled with KOH activation in argon atmosphere. Under optimum conditions, the BET surface area?SBET?, average pore size?Dap? and non-Vmic percent of PC3-18-6 made with the masses of CT, nano-ZnO, KOH at 3 g, 18 g, 6 g reaches 1789 m²/g, 3.3 nm and 87%, respectively. The specific capacitance of PC3-18-6 is up to 113 F/g and the energy density of PC3-18-6 capacitor reaches 65.2 Wh/kg at 0.05 A/g in BMIMPF6 electrolyte. The specific capacitance of PC3-18-6 remains 42 F/g at 20 A/g, showing good rate performance.Dothideoid PCs?DPCX-Y-Z-T? were prepared from anthracene oil?AO? by nano-ZnO template strategy coupled with KOH activation in argon atmosphere?X, Y and Z represent the mass of AO, nano-ZnO and KOH respectively, T is carbonization temperature?. The specific capacitance of DPC8-20-10-800 and DPC8-25-10-800 reach 299F/g and 411 F/g at 0.05 A/g respectivly, and retanis 195 F/g and 267 F/g at 200 A/g in 6 M KOH electrolyte, exhibiting high capacitance and excellent rate performance.The high capacitance of DPC8-25-10-800 is ascribed to its high specific surface area?2498 m²/g? and high content of oxygen containing functional groups. The DPC8-30-10-800 and DPC8-30-10-900 show high energy density of 101 Wh/kg and 78Wh/kg in BMIMPF6 ion liquied electrolyte owing to their extended pore and high content of non-Vmic.