Synergistic interaction between pseudocapacitive Fe₃O₄ nanoparticles and highly porous silicon carbide for high-performance electrodes as electrochemical supercapacitors

Composites of micro- and mesoporous SiC flakes (SiCF) and ferroferric oxide (Fe₃O₄), SiCF/Fe₃O₄, were prepared via the chemical deposition of Fe₃O₄ on SiCF by the chemical reduction of an Fe precursor. The SiCF/Fe₃O₄ electrodes were fabricated at different Fe₃O₄ feeding ratios to determine the optimal Fe₃O₄ content that can maintain a high total surface area of SiCF/Fe₃O₄ composites as well as cause a vigorous redox reaction, thereby maximizing the synergistic effect between the electric double-layer capacitive effects of SiCF and the pseudo-capacitive effects of Fe₃O₄. The SiCF/Fe₃O₄ electrode fabricated with a Fe₃O₄/SiCF feeding ratio of 1.5:1 (SiCF/Fe₃O₄(1.5)) exhibited the highest charge storage capacity, showing a specific capacitance of 423.2 F g^-1 at a scan rate of 5 mV s^-1 with a rate performance of 81.8% from 5 to 500 mV s^-1 in an aqueous 1 M KOH electrolyte. The outstanding capacitive performance of the SiCF/Fe₃O₄(1.5) electrode could be attributed to the harmonious synergistic effect between the electric double-layer capacitive contribution of the SiCF and the pseudocapacitive contribution of the Fe₃O₄ nanoparticles introduced on the SiCF surface. These encouraging results demonstrate that the SiCF/Fe₃O₄(1.5) electrode is a promising high-performance electrode material for use in supercapacitors.