Potassium-assisted carbonization of pyrrole to prepare nanorod-structured graphitic carbon with a high surface area for high-rate supercapacitors

Compared with traditional carbonaceous precursors (polymers or natural sources), small molecular organic precursors (SMOPs), such as pyrrole, furan and C6H5X (X = Cl, Br, I), are a class of commercial carbonaceous precursors with strong plasticity, wide accessibility and long-term sustainability. However, it is difficult to directly convert these SMOPs into porous carbon nanomaterials (PCNMs) because of their uncontrolled vaporization under high-temperature pyrolysis. Here, we report a novel and bottom-up strategy to prepare PCNMs by using the potassium-assisted carbonization of pyrrole. Depending on the pyrolysis temperature, the obtained materials possess nanorod microstructures with a high degree of graphitization and a high surface area of 2340 m(2) g(-1). Additionally, the pore-making mechanism for this strategy is explored and ascribed to the chemical activation of KOH, the intercalation effect and physical activation of potassium. Based on this mechanism, three PCNMs are prepared, with an optimized PCNM electrode for supercapacitors exhibiting excellent rate performance (65% capacitance retention at 80 A g(-1)) and long-term cyclic stability (86% capacitance retention after 10000 cycles). The device delivers 18.5 Wh kg(-1) at a high power density of 62.6 kW kg(-1). This simple strategy paves the way for the use of largely unexplored SMOPs in preparing PCNMs for energy storage applications. (C) 2019 Elsevier Ltd. All rights reserved.