KOH activation was applied to obtain hierarchical porous carbons from banana peels. The influence of alkali/carbon ratio and activation temperature on pore feature and electrochemical performance of C/S composites was investigated. Pore volume was found to have a positive correlation with discharge capacity and cycle stability and an inverse correlation to overall impedance. Porous carbon with largest pore volume of 2.04 cm(3) g(-1) obtained at alkali/carbon ratio of 3.5 and 800 degrees C was able to accommodate 65 wt.% sulfur. Highest discharge capacity of 796 mA h g(-1) was delivered at 0.5 C and 80.5% of it was kept after 100 cycles. After 500 cycles, the composite still delivered a high discharge capacity of 615 InA h g(-1), indicating superior cyclestability. Optimization on sulfur content in C/S composite was explored and 65 wt.% was found to be the best proportion. Both too low and too high sulfur content resulted in inferior electrochemical performance.