Hierarchical polyimide-derived nitrogen self-doped carbon nanoflowers for large operating voltage aqueous supercapacitor

Abstract

Abstract Herein, novel polyimide (PI) nanoflowers with intertwined nanosheets is synthesized by one-step hydrothermal bottom-up self-assembly crystal growing process by using low-cost aromatic diamine and dianhydride as monomers. Then, hierarchical polyimide-based porous carbon nanoflowers (PI-CNFs) are prepared by synchronous activation and catalytic carbonization approach utilizing polyimide as carbon precursor and FeCl3 as activating agent and catalyst. Owing to its unique interlaced porous nanosheet structure, high specific surface area and high nitrogen doping content, the PI-CNFs possesses high specific capacitance, capacity rate performance and overlength cycle life. In addition, a novel symmetrical aqueous supercapacitor assembled with PI-CNFs has a large operating voltage of 2.0 V, a high specific energy of 18.3 Wh kg−1 at specific power of 500 W kg−1, as well as excellent cycling stability. Therefore, this work will propose an affordable strategy for designing novel polymer nanosheets, and open up the possibility of easy preparation, environmentally friendly and low-cost synthetic polymers-based carbon nanosheets to meet the energy storage demands.