Graphite pencil derived carbon through activation-carbonization synthesis strategies for solid-state symmetric supercapacitor

Due to inherent electrochemistry, reproducibility, low cost, and disposability, graphite pencil has attracted widespread application in electrochemical energy storage fields. In this study, graphite pencil derived carbon was successfully synthesized via activation-carbonization strategies for solid-state symmetric supercapacitor. The surface-structural engineering could efficiently optimize the surface characteristics of derived carbon, thereby enhancing the capacitive performance. The best specific areal capacitance value was 995.0 mF cm- 2 at a current density of 2 mA cm- 2. In a practical application, a symmetric device showed excellent specific areal capacitance (energy density of 0.025-0.104 mWh cm- 2 with a power density of 0.397-11.040 mW cm- 2) and long-term cyclic stability over 3000 cycles (85.6 % capacity retention). The device could further supply power to a desired LED pattern, showcasing its great practical application. This study shows that graphite pencil derived carbon as an electrode material in supercapacitors has high potential to increase the capacitive performance.