Engineering active sites on nitrogen-doped carbon nanotubes/cobaltosic oxide heterostructure embedded in biotemplate for high-performance supercapacitors

At present, both easy agglomeration of carbon nanotubes themselves and waste caused by chemical vapor deposition (CVD) have great pollution, which limits the use of carbon nanotubes (CNTs). A large number of hollow polyhedrons containing N-doped carbon nanotubes and Co 3 O 4 nanoparticles (Co 3 O 4 NPs) were well fabricated on a biotemplate by hydrothermal method , stirring method and pyrolysis process . The regular polyhedron was uniformly arranged on the external surface of diatomite with a natural porous structure , which aims to avoid the agglomeration of CNTs. The electrochemical testing result shows that the composite has promising electrochemical performance, which is embodied in a high specific capacity 894.6 F/g at 2 A/g, good rate performance and high cycling property. Finally, an assembled Co 3 O 4 NP@CNTs@Diatomite//GR asymmetric supercapacitor has maximal energy density of 36.8 Wh/kg and maximal power density of 16,326.6 W/kg. Indeed, electrode design in this work provides an environmental synthesis idea for the decoration of CNTs on a certain substrate and displays an original electrode material based on diatomite.