Improved supercapacitor performance based on sustainable synthesis using chemically activated porous carbon

Abstract

Porous carbon-based materials are among the most promising materials for future electrochemical energy storage and conversion and are sustainable and environmentally acceptable. The development of highly porous carbon compounds from biomass has become a popular topic of study. Herein, we report interconnected porous-structured carbon obtained from a biowaste precursor. Pine tree (Casuarina) seeds were carbonized by using 9 M concentrated sulfuric acid (H2SO4), and the obtained pine tree seed carbon (PTC) was activated by mixing various ratios with potassium hydroxide (1:1, 1:3, 1:5 ratio) and performing simple microwave pyrolysis. The pore size and surface area of the generated carbon could be fine-tuned. The surface area increased considerably as the KOH concentration increased, with an excellent specific surface area of 929.9 m2 g−1 (1:3 mass ratio). The synthesized porous carbon showed a high charge storage capacitance of 210 F g− 1 at 1 A/g, as well as remarkable capacitance retention after 10,000 charge/discharge cycles, even at a high current density. The remarkable electrochemical storage behaviour of hierarchically porous structured carbon networks is related to the optimal combination of micro- and mesoporous morphology with increased defect sites at the edges, which results in a higher surface area and enhanced conductivity.