High-value conversion of invasive plant into nitrogen-doped porous carbons for high-performance supercapacitors

Given the harm caused by invasive plants to the environment and the high cost of treatment, we propose highvalue transformation and utilization for invasive plants. Highly porous carbon derived from invasive plant (Canada goldenrod) was successfully synthesized through a feasible and green carbonization approach, which was firstly utilized as supercapacitor electrode. It is found that the addition of nitrogen (N)-rich chlorella could positively increase the N content and considerably boost the specific surface area up to 2231.41 m2 g- 1 for the resultant Carbon-GC1-800, which are crucial factors for accelerating the ion transport and improving the capacitive behaviors. Notably, Carbon-GC1-800 exhibits the highest ratio (70.9 %) of microporous volume to total pore volume. The electrochemical properties of Carbon-GC1-800 electrode exhibits an outstanding specific capacitance of 388.2 F g-1 at a current density of 0.5 A g-1 and a superb rate capability of 75.7 % from 0.5 A g-1 to 10 A g- 1. The assembled symmetric supercapacitor with ionic liquid as electrolyte demonstrates the exceptional maximum power density of 8753.7 W kg-1 and peak energy density of 59.3 Wh kg- 1. This study presents the novel ideas and effective techniques to produce porous carbons for energy storage from invasive plant resources.