Hierarchical porous activated carbon derived from olives: Preparation, (N, S) co-doping, and its application in supercapacitors

For the structure and morphology of supercapacitor (SC) electrode materials, activation agent and processing technology are two important factors. Herein, we have developed an activated carbon material with high electrochemical performance obtained from olive husk, which is pre-treated by hydrothermal route followed activation treatment by dual activators. The effect of activation agents and heteroatom doping (N, S) on the structure and electrochemical performance of the obtained materials are deeply investigated. Optimized activation temperature at 700 °C was applied to create hierarchical porous carbon structure. The Olive husk-derived Activated Carbon with KOH/NaOH (OACKNa) has a specific surface area of 2900 m2·g−1, exhibits outstanding specific capacitance of 549 F·g−1 at 1 A·g−1 with high capacitance retention of 79.5% when the current density reaches up 30 A·g−1. Furthermore, OACKNa based symmetric SC device displays marvelous cyclic stability with rate capability of 93.2% after 10,000 cycles at 10 A·g−1. Interestingly, OACKNa device delivers high specific energy of 38.8 Wh·kg−1 even at ultrahigh specific power of 650 W·kg−1 at 1 A·g−1. Therefore, the obtained OACKNa with low-cost synthesis combined with the attractive electrochemical performances is a promising electrode material for supercapacitors.