Supercapacitive charge storage properties of porous carbons derived from pine nut shells

Abstract

High-performance porous carbon electrode materials derived from pine nut shells are prepared through KOH, H3PO4 and steam activation. The different morphologies and structures of the porous carbons are studied to investigate the mechanisms of pore tailoring and the interaction effects among the activation agent, pore structure and properties of the porous carbons. The porous carbons are all excellent electrode materials for supercapacitors with high capacitance characteristics due to their well-developed pore structures. The electrochemical performance is strongly related to pore structure and distribution, followed by specific surface area (SSA). The 3D network porous structure of porous carbon benefits ion storage and electrolyte internal diffusion, resulting in superior electrochemical properties such as an SSA of 1471 m2/g, an energy density of 23.45 Wh/kg and a capacitance of 241 F/g. Moreover, after 10,000 cycles, 99% of capacitance was retained at 5 A/g in 6 M KOH aqueous solution. A feasible approach for high-value utilization of low-cost biomass waste is presented.