A multifunctional activation strategy of ultrathin carbon layers-intertwined carbon microspheres clusters towards markedly enhanced capacitance

Abstract

Exploiting a facile and effective synthetic strategy integrated with pore-forming and nitrogen doping is highly desirable for developing superior electrode materials. Here, we proposed an ingenious multifunctional activation strategy to synthesize ultra-thin graphite-like carbon layers interwoven N-doped porous carbon microspheres clusters (donated by NCSC) by pyrolyzing self-polymered dopamine nanosphere precursors and g-C3N4, in which g-C3N4 simultaneously served as a pore-foaming agent, nitrogen source and a regulator of nitrogen configuration. The as-prepared NCSC exhibited three-dimensional interwoven porous structures with more favorable hydrophilic interface, high porosity with interconnected open pore structures, and pyrrole-N and pyridine-N dominated high nitrogen doping content (5.70 at.%). In the three-electrode test system, NCSC delivered significantly increased capacitance (235.4F g−1 at 1A g−1) compared to that of dopamine nanospheres derived carbon microspheres clusters(CSC) (124.7F g−1 in 1A g−1), and an excellent cycling durability (97% retention at 20A g−1 after 10,000 cycles). More impressively, the NCSC-based symmetrical supercapacitor with 1.0 M neutral Na2SO4 electrolyte can realize a wide voltage range of 1.8 V, rendering a specific energy density of 14.64 Wh kg−1 at 450 W kg−1. Such kind of integrated multi-functional activation strategy can provide new ideas for developing advanced materials to significantly boost capacitance performance.