Effects of structure of heat-treated pitch precursors on electrochemical properties of pitch-based activated carbons

Activated carbons (ACs) prepared from heat-treated pitch precursors with KOH activation are used to fabricate electrodes for electric double-layer capacitors. The electrochemical properties of pitch-based ACs were investigated based on the structural differences between the pitch precursors prepared at different heat treatment temperatures. The high crystallite height of the pitch precursor before KOH activation resulted in improved porous structures having a high specific surface area and total pore volume, while the high crystallite width of the pitch precursors before KOH activation was responsible for the high micropore volume fraction. As a result, the A-HP1 and A-HP2, which were prepared from heat-treated pitch precursor, showed improved electrochemical properties due to the improved porous structures resulting from the high total pore volume fraction. In particular, A-HP1 has higher specific capacitance than A-HP2, because of the high micropore volume fraction of the former.