Multiple Functional Biomass-Derived Activated Carbon Materials for Aqueous Supercapacitors, Lithium-Ion Capacitors and Lithium-Sulfur Batteries

Biomass-derived activated carbon electrode materials have been synthesized by carbonization and KOH activation processes from an agriculture waste - rice husk, composed of organic compound and silica. The surface area of activated carbon reached 1098.1 m(2)/g mainly including mesopores and macropores due to the template effect of silica in rice husk. Owing to the existence of mesopores and macropores, the as-obtained activated carbon materials can be used in aqueous supercapacitors, lithium-ion (Li-ion) capacitors and lithium-sulfur (Li-S) batteries. In KOH electrolyte, fast rate performance (as high as 2 V/s) was obtained due to the existence of ideal electrical double layer capacitance. In organic electrolyte, high voltage (2.5 V) was achieved. Activated carbon electrode for Li-ion capacitor also showed capacity of 17 mAh/g at 100 mA/g with the high voltage range of 2.5 V. The capacities of sulfur- activated carbon in Li-S batteries were 1230 and 970 mAh/g at the current densities of 0.1 and 0.2 C. The present results showed that activated carbon materials with mesopores were good host to immobilize polysulfides.