Interconnected mesoporous carbon sheet for supercapacitors from low-cost resources

Interconnected mesoporous carbon sheets (MCSs) were prepared from cheap coal tar pitch with low-cost CaCO₃ nanoparticles and cetyltrimethyl ammonium bromide (CTAB) as porogens for supercapacitors. The results show that the surface area of MCSs can be tuned in the range of 87-167 m² g^-1. The interconnected MCS_2-1-1 made at 2:1:1 of CaCO₃/coal tar pitch/CTAB mass ratio retains a capacitance of 87 F g^-1 at 0.1 A g^-1 after 100 cycles in ionic liquid electrolyte with high retention of 93.1%, showing excellent cycle stability. The energy density of MCS_2-1-1 capacitor only drops from 64.18 Wh kg^-1 to 22.19 Wh kg^-1 with the average power density increasing from 115 W kg^-1 to 4267 W kg^-1, demonstrating good rate performance. This work suggests a low-cost way to synthesize high performance MCS for energy storage materials.