2015 Volume 40 Issue 4 Pages 319-324
We prepared the spent coffee grounds (SCG) and controlled the steam activation process for them in order to develop SCG-derived activated carbon with uniform micropores that were similar to those of KOH-activated phenolic resin carbon (MSP-20). The SCG-derived activated carbon that we obtained had a high yield, a high specific surface area, and uniform-sized micropores, and it exhibited characteristics different from those of conventional structures containing both micropores and mesopores. The laminated multi-layer EDLC cells achieved a capacitance of higher than 75 F/g. They were produced with only small variations. The Nyquist plot generated from the impedance measurements showed a fairly vertical rise that can be attributed to the blocking electrode in the low frequency range. This confirms that the pores in the electrodes were used effectively. It was demonstrated that the electric double layer characteristics and impedance characteristics of the SCG capacitors can be changed by controlling the raw material preparation and its activation conditions.
