Hydrothermal growth of FeMoO₄ nanosheets on electrospun carbon nanofibers as freestanding supercapacitor electrodes

In this study, an electrospinning method was used to produce highly conductive freestanding carbon nanofibers (CNFs). The freestanding CNFs are compatible with hierarchical growth techniques, such as hydrothermal processes, for the nanostructure engineering of supercapacitor electrodes with enhanced electrochemically active sites. Therefore, the flower-like FeMoO₄@CNF nanosheets were investigated to improve the electrochemical performance using aqueous and neutral electrolytes (Na₂SO₄ and K₂SO₄). The optimized FeMoO₄@CNF electrode exhibits areal capacitances of 252 and 220 mF·cm⁻² at a high current density of 2.5 mA·cm⁻² with Na₂SO₄ and K₂SO₄ electrolytes, respectively. The wide potential window (1.6 V) of the symmetric supercapacitor delivered maximum energy densities of 22.4 and 19.6 μWh·cm⁻² at a power density of 2 mW·cm⁻² for Na₂SO₄ and K₂SO₄ electrolytes, respectively.