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 high-value 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.