Additive-Driven Self-Assembly of Well-Ordered Mesoporous Carbon/Iron Oxide Nanoparticle Composites for Supercapacitors

Abstract

Ordered mesoporous carbon/iron oxide composites were prepared by cooperative self-assembly of poly­(<i>t</i>-butyl acrylate)-block-polyacrylonitrile (PtBA-<i>b</i>-PAN), which contains both a carbon precursor block and a porogen block, and phenol-functionalized iron oxide nanoparticles (NPs). Because of the selective hydrogen bonding between the phenol-functionalized iron oxide NPs and PAN, the NPs were preferentially dispersed in the PAN domain and subsequently within the mesoporous carbon framework. Ordered mesoporous carbon nanocomposites with Fe₂O₃ NPs mass loadings as high as 30 wt % were obtained upon carbonization at the block copolymer composites at 700 °C. The morphology of the mesoporous composites was studied using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and N₂ adsorption. The results confirmed high-fidelity preservation of morphology of the NP-doped block copolymer composites in the mesoporous carbon composites. The electrochemical performance of the mesoporous composite films improved significantly upon the addition of iron oxide NPs. The specific capacitance (<i>C</i>_g) of neat mesopororous carbon films prepared from PtBA-<i>b</i>-PAN was 153 F/g at a current density of 0.5 A/g, whereas films containing 16 and 30 wt % Fe₂O₃ present as well-dispersed NPs within the mesoporous carbon framework exhibited capacitances of 204 and 235 F/g, respectively. The well-defined mesoporous in the template carbon structure together with high loadings of iron oxide nanoparticles are promising for use in supercapacitor applications