Waste bio-tar based N-doped porous carbon for supercapacitors under dual activation: performance, mechanism, and assessment

Abstract

Bio-tar extra-produced from biomass pyrolysis is prone to pose a threat to environment and human health. A novel N-doped porous electrode from bio-tar was produced under dual-activation of urea and KOH in this study. One-pot dual-activation played significant roles in N-functional group and micro-mesoporous structure, which resulted in the carbon material with the highest of nitrogen content (4.08%) and the special surface area (1298.26 m²·g⁻¹). Specifically, the potential mechanisms of pore formation and N-doping in the one-pot dual-activation strategy were also proposed as a consequence, the one-pot dual-activated carbon material displayed excellent electrochemical performance with the highest capacitance of 309.5 F·g⁻¹ at 0.5 A·g⁻¹, and the unipolar specific capacitance remained with cyclic characteristics of 80.1% after 10,000 cycles in two-electrode symmetric system. Furthermore, the one-pot dual-activation strategy could create a profit of $1.64–$2.38 per kilogram of bio-tar processed without considering the initial investment and labor costs, which provides new perspectives for the utilization of waste bio-tar.

Highlight

•	Coupling urea with KOH preferentially formed a micro-mesoporous biocarbon structure.
•	Potential mechanisms of one-pot dual activation of biocarbon were proposed.
•	The preparation of porous carbon from bio-tar can bring considerable economic benefits.

Funding

National Natural Science Foundation of China(52376220)

National Key R&D Program of China(2022YFD2002102)