Nitrogen-Oxygen Co-Doped Carbon-Coated Porous Silica/Carbon Nanotube Composites: Implications for High-Performance Capacitors

In this study, a simple in situ growth method is used to directly synthesize nitrogen-oxygen co-doped carbon-coated porous silica@CNT (CNT@mSiO(2)@NC) composites with open-tip and multilayer sandwich tubular structures. As the sacrificial template method is used to etch most of the porous SiO2 layer, the obtained nanotube has excellent properties. The composite has a high specific capacity of about 300 F g(-1) at 2 A g(-1), and the capacity retention rate reaches 91.30% after 10,000 cycles at 40 A g(-1). The reasons for the superior performance can be ascribed to the synergistic effect of a suitable specific area (483.18 m(2) g(-1)), abundant nitrogen/oxygen functional groups (4.70 at. % N and 7.52 at. % O), and a porous silica supporting template. The power density of the assembled symmetric supercapacitor is 760 W kg(-1) at the energy density of 16 W h kg(-1). Moreover, the capacity retention rate is 82.70% after 2500 cycles at a current density of 2 A g(-1). The N/O co-doped porous CNT@mSiO(2)@NC electrode material has adjustable porosity and enriched active sites, which has broad application prospects in high-performance supercapacitors.

Automated summary

In this study, nitrogen-oxygen co-doped carbon-coated porous silica@CNT composites were synthesized using a simple in situ growth method. The composites exhibited excellent electrochemical properties and cycle life, making them promising materials for high-performance supercapacitors.