Green synthesis of porous carbon for supercapacitors from pine cone/phoenix tree fruit fluff by hydrothermal pre-activation method

• A porous carbon electrode material was prepared from pine cone/phoenix tree fruits. • Hydrothermal pre-activation can greatly increase the specific surface area of carbon. • Hydrothermal pre-activation can avoid corrosion of quartz glass at high temperature. Herein, a novel porous carbon was prepared from pine cone/phoenix tree fruit (PCT) by hydrothermal pre-activation method. The PCT-derived porous carbon with appropriate PCT/KOH mass ratio exhibited high specific surface area (2428.72 m 2 /g) and charge storage capacity. The as-prepared symmetrical supercapacitor displayed an energy density of 5.43 Wh/kg at 1000 W/kg, exhibiting excellent cycling stability with maintaining capacitance 99.74 % and coulombic efficiency 99.69 % after 4000 charge–discharge cycles. Additionally, the hydrothermal pre-activation could avoid corrosion of quartz glass reactor at high temperature. This work highlights the potential of hydrothermal pre-activation of the biomass waste PCT in developing carbon-based supercapacitor by a environmentally friendly strategy.