Synthesis of multiple heteroatom-doped mesoporous carbon/silica composites for supercapacitors

In this study we synthesized a series of tunable multiple heteroatom?doped mesoporous carbon/silica composites directly through a facile tricomponent co-assembly approach using a triazine?formaldehyde phenolic resol (Nresol) as the C and N atom source, tetraethyl orthosilicate (TEOS) as the Si atom source, and the diblock copolymer poly(ethylene oxide?b??-caprolactone) (EC) as the structure-directing template. Small-angle X-ray scattering and transmission electron microscopy revealed that mesophase transformations of the N-resol/EC/ TEOS hybrids, from double-gyroid to cylinder to lamellar structures, occurred upon increasing the TEOS content (i.e., double-gyroid at 60/40/0 and 60/40/5; cylinder at 60/40/10; lamellar at 60/40/20 and 60/40/30; shortrange-order structure at 60/40/50). After removing the EC template by heating sequentially at 400 and 700 ?C, the resultant multiple heteroatom?doped mesoporous carbon/silica composites had high N atom (up to 13.0 wt %), O atom (up to 21.5 wt%), and Si atom (up to 6.8 wt%) contents and double-gyroid, cylinder, and wormlike mesostructures. These multiple heteroatom?doped mesoporous carbon/silica composites had exceptionally high supercapacitor efficiencies, with excellent electrochemical specific capacitances (up to 827 F g-1 at a current density of 0.5 A g-1) and very high stabilities (up to 96.64% at a current density of 10 A g-1 for up to 10 000 cycles). Such mesoporous carbon/silica composites would appear to have tremendous potential for use as highperformance supercapacitors in energy storage applications.

Automated summary

In this study, a series of tunable multiple heteroatom-doped mesoporous carbon/silica composites were synthesized through a facile tricomponent co-assembly approach. These composites, with high N, O, and Si atom contents and different mesostructures, exhibited exceptional supercapacitor efficiencies, making them promising for high-performance energy storage applications.