Facile fabrication of MnOx and N co-doped hierarchically porous carbon microspheres for high-performance supercapacitors

Abstract

Facile fabrication of manganese oxide (MnOx, 0<x<2) and nitrogen (N) co-doped carbon microspheres (MnOx-N-CS) has been firstly developed by one-pot construction of Mn-functionalized melamine-formaldehyde (Mn-MF) resin spheres before pyrolysis. The resulting hybrids bear evenly dispersed MnOx and N moieties in situ anchored on hierarchically porous carbon microspheres formed simultaneously. The capacitive performance is greatly tailored by varying the Mn/melamine molar ratio in the synthetic mixture and pyrolysis temperature. It is found that the MnOx-N-CS hybrid (0.008wt% Mn, pyrolyzed at 800°C) exhibits the highest specific capacitance up to 258Fg−1 at a scan rate of 1mVs−1 (in 6M KOH), and keeps a high capacitance retention ratio of 98% after 5000 cycles. The synergism between MnOx, N moieties and carbon spheres proves to be responsible for the remarkably improved performance, as compared to the pure carbon sphere and MnOx (N)-doped carbon sphere. The well-developed MnOx-N-CS hybrids highlight the great potentials for widespread supercapacitor applications.