Role of fluorination in improvement of the electrochemical properties of activated carbon nanofiber electrodes

In this study, we investigated the role of fluorination in improving the electrochemical properties of activated carbon nanofiber (ACNF) electrodes. The ACNFs were prepared with various textural properties and then fluorinated. The electrochemical properties of the resulting ACNFs were subsequently evaluated to investigate the effect of the fluorination of the prepared ACNFs with various textural properties on the electrochemical properties. The specific capacitances of the ACNF electrodes increased by 15.8–47.3% after fluorination, although the specific surface area and the total pore volume decreased significantly; these results suggest that the introduction of CF functional groups onto the ACNF surface was more important than the induction of changes in the textural properties of the ACNF samples with respect to improving the electrochemical properties of the ACNF electrodes. The retained capacitances of the ACNF electrodes also increased 2–12% after fluorination, although the etching effect of the fluorination significantly collapsed the mesopores; these results suggest that the CF functional groups were electrochemically active even at a high scan rate.

Graphical abstractFluorination of the activated carbon nanofibers (ACNFs) increased the specific capacitances of the ACNFs, even with the decreased specific surface area and total pore volume, suggesting the more important role of the fluorination is introducing CF functional groups than inducing the changes in textural properties.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Fluorination of the ACNFs decreased the specific surface area, total pore volume, and mesopore volume. ► Fluorination of the ACNFs increased the specific capacitance of the ACNFs, even with decreased textural properties. ► These suggest that introducing CF groups is the more important role of fluorination than inducing the changes in textural properties.