N, S, O Self-Doped Porous Carbon Nanoarchitectonics Derived from Pinecone with Outstanding Supercapacitance Performances.

Biomass-derived porous carbons are considered as one of the most promising electrode materials for supercapacitors due to their low-cost and natural abundance. In this work, pinecone is used to fabricate biomass N, S, O-doped porous carbon via one-step carbonization process with KOH activation. By optimizing the additive amount of KOH and calcination temperature, the asprepared product shows a high specific surface area and pore volume up to 1593.8 m² g-1 and 0.8582 cm³ g-1, respectively. As an electric double-layer capacitor (EDLC) electrode, the N, S, O-doped porous carbon exhibits a high specific capacitance of 285 F g-1 at 0.5 A g-1 and good rate performance with a capacitance retention of 78.6% from 0.5 to 20 A g-1. Furthermore, the as-assembled symmetric supercapacitor with 6 mol L-1 KOH as electrolyte possesses a promising energy density of 6.34 Wh kg-1 and a power density of 250 W kg-1. Outstanding cycling stability was also demonstrated with 94.4% capacitance retention after 10,000 charge/discharge cycles at 1 A g-1.