Controlling synthesis of nitrogen-doped hierarchical porous graphene-like carbon with coral flower structure for high-performance supercapacitors

Abstract

In this work, nitrogen-doped hierarchical porous graphene-like carbon (NCFC) with coral flower structure is synthesized by an eco-friendly and inexpensive template carbonization method, with cellulose acetate (CA) as carbon precursor, MgO as template, and urea as nitrogen agent. The as-synthesized NCFC features loose coral flower composed of ultra-thin graphene-like sheets and has a high specific surface area of 937 m2 g−1. As the electrode material for supercapacitors, the NCFC shows a high capacitance of 333 F g−1 at 1 A g−1 in 1 mol L−1 H2SO4 electrolyte and a good rate performance (the specific capacitance at 10 A g−1 retains 84% relative to 1 A g−1), and excellent cycle stability with 100% capacitance retention after 10,000 cycles. The symmetric supercapacitor (SSC) was assembled by using NCFC in 1 mol L−1 H2SO4 electrolyte. The device exhibits the maximum energy density of 21 W h kg−1 at a power density of 750 W kg−1 in a potential window of 0 to 1.4 V. Our work is expected to pave a new way for scale-up production of high-performance graphene-like carbon from natural cellulose with a simple, eco-friendly, and low-cost method.