| 초록 |
Transition metal ferrites (MFe2O4, M= Co, Ni, Zn) have emerged as excellent electrode materials for supercapacitor application because of their ease of synthesis, stability, abundance and benign nature. The transformation of MFe2O4 surface into oxyhydroxides (MFe2O4@M(Fe)OOH) under anodic potential is crucial to achieve high capacitive performance. In this study, we investigate how the degree of crystallinity in MFe2O4 affects the ease of MFe2O4@M(Fe)OOH formation and capacitance of MFe2O4 . Thermal annealing conditions (i.e. time (Tt) and temperature (T)) were tuned to control the crystallinity in MFe2O4. This was monitored using XRD, SAED and HR-TEM analysis. These methods were also used to elucidate MFe2O4 transformation into MFe2O4@M(Fe)OOH under anodic potential. Our results show a direct correlation between crystallinity and supercapacitance performance. These findings could theoretically be applied to improve the supercapacitance of other metal-oxide based electrodes. |
