From micro to nano: Size-driven enhancement of electrochemical kinetics in FeCo2O4 electrodes

초록

The effect of particle size and morphology on electrochemical performance and charge storage kinetics was investigated by the successful synthesis of microscale FeCo2O4 particles (FCO-P) and electrospun nanoscale FeCo2O4 nanofibers (FCO-NF) using urea combustion and electrospinning methods. The formation of phase pure spinel FeCo2O4 with different micro and nano scale morphologies was confirmed by XRD and FESEM analysis. Electrochemical measurements in 2 M KOH showed that the specific capacitance of FCO-NF (299 F g-1 at 1 mV s-1) was significantly higher than that of FCO-P (176 F g-1). Galvanostatic charge-discharge analysis further proved the superior capacitance retention of the nanofibrous electrode. Electrochemical impedance spectroscopy analysis proved markedly lower charge-transfer resistance of FCO-NF (0.04 Omega) than that of FCO-P (0.6 Omega). The kinetic analysis of Dunn suggested that FCO-NF demonstrated enhanced charge-transfer kinetics and electroactive-site utilization, which was ascribed to its larger electroactive surface area and shorter ion-diffusion pathways. The results demonstrate the significant enhancement in the electrochemical behavior of FeCo2O4 through nanoscale morphological engineering, and the potential of electrospun FeCo2O4 nanofibers as high performance supercapacitor electrodes.

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