Nitrogen-doped porous carbon monoliths from molecular-level dispersion of carbon nanotubes into polyacrylonitrile (PAN) and the effect of carbonization process for supercapacitors

Abstract

Nitrogen-doped porous carbon monoliths (NDP-CMs) have long been pursued as the desirable supercapacitor electrode materials. However, the currently effective template methods and Lewis acid/base activation strategy suffer from the drawbacks of either high costs or tedious steps. We report on a simple and practicable novel method to the production of CNTs constructed NDP-CMs. Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being dispersed into tubular level of dispersions (mono-dispersions), were used as the starting material and NDP-CMs were obtained through a direct carbonization process. First, PAN/CNT based mesostructured polymeric monoliths with interconnected networks were formed using a template-free temperature-induced phase separation (TTPS) method and the mono-dispersed CNTs networks act as the backbones of PAN molecules. Then, NDP-CMs with a surface area of 840 m2/g and a pore diameter 2.48 nm were obtained through heat treatment. Thus, the NDP-CMs based supercapacitor demonstrated a reversible specific capacitance of 246 F/g. Furthermore, pyridinic nitrogen and quaternary nitrogen species contribute significantly to the advantageous electrochemical activities of NDP-CMs.