Gram-scale production of B, N co-doped graphene-like carbon for high performance supercapacitor electrodes

Abstract

Boron and nitrogen co-doped graphene-like carbon (BNC) with a gram scale was synthesized via a two-step method including a ball-milling process and a calcination process and used as electrode materials for supercapacitors. High surface area and abundant active sites of graphene-like carbon were created by the ball-milling process. Interestingly, the nitrogen atoms are doped in carbon matrix without any other N sources except for air. The textual and chemical properties can be easily tuned by changing the calcination temperature, and at 900 oC the BNC with a high surface area (802.35 m2/g), a high boron content (2.19 at%), a hierarchical pore size distribution and a relatively high graphitic degree was obtained. It shows an excellent performance of high specific capacitance retention about 78.2% at high current density (199 F/g at 100 A/g) of the initial capacitance (254 F/g at 0.25 A/g) and good cycling stability (90% capacitance retention over 1000 cycles at 100 A/g) measured in a three-electrode system. Furthermore, in a two-electrode system, a specific capacitance of 225 F/g at 0.25 A/g and a good cycling stability (93% capacitance retention over 20,000 cycles at 25 A/g) were achieved by using BNC as electrodes. The strategy of synthesis is facile and effective to fabricate multi-doped graphene-like carbon for promising candidates as electrode materials in supercapacitors.