Flash Nitrogen-Doped Graphene for High Rate Supercapacitors

Novel structured graphene produced by an environmentally-friendly and high-yielding method together with excellent electrochemical energy storage performance is pursued. A one-pot, solvent-and catalyst-free flash Joule heating approach is developed for synthesizing nitrogen-doped graphene and so named as flash nitrogen-doped graphene (FNG). The precursors of amorphous carbon black and urea are quickly converted into high-quality FNG in less than 1 s under a short electrical pulse with a bright flash of blackbody radiation. The prepared FNG product features high graphitization with a turbostratic structure. It delivers a high surface-area-normalized capacitance of 152.8 mu F cm(-2) at 1 A g(-1), an extraordinary rate capability with prominent capacitance retention of 86.1% even at 128 A g(-1), and a knockdown relaxation time of 30.2 ms. Besides, the assembled symmetric quasi-solid-state supercapacitor exhibits a high energy density of 16.9 Wh kg(-1) and a maximum power density of 16.0 kW kg(-1), as well as desirable cyclic stability (91.2% of initial capacitance is maintained after 10000 cycles). These outstanding performances show that FNG is a promising candidate for exploiting high-performance supercapacitors.

Automated summary

A novel structured graphene, named flash nitrogen-doped graphene (FNG), has been synthesized using a solvent-and catalyst-free flash Joule heating method. FNG features high graphitization with a turbostratic structure and exhibits high surface-area-normalized capacitance and exceptional rate capability. It also demonstrates desirable cyclic stability, making it a promising candidate for high-performance supercapacitors.