Structure and electrochemical performance of hollow tube activated carbon prepared from cotton as electrode material for electric double layer capacitor

Hollow tube-like activated carbon(HTAC) was fabricated by a simple and efficient carbonization method with cotton as carbon precursor activated by KOH without any template. The activation time from 0 to 90 min showed no significant effect on the micro-morphology, but greatly influenced the specific surface area and electrochemical performance. In the end, it was found that the sample activated for 60 min(HTAC-60) has a higher specific surface area of 2600 m2/g, a larger pore volume of 1.52 cm3/g and a greater specific capacitance of 483 F/g at a current density of 0.2 A/g in 1 mol/L H2SO4. Moreover, the sample HTAC-60 shows excellent cycle stability(only 12.2% loss after 5000 cycles) and a high energy density of 67.1 or 37.2 W·h·kg–1 at a power density of 200 or 1000 W/kg, respectively, operated in a voltage range of 0—1.0 V in 1 mol/L H2SO4. The results indicate that cotton can potentially be used as a raw material for producing low cost and high performance activated carbon electrode materials for electric double layer capacitor.