The impact of morphologies and electrolyte solutions on the supercapacitive behavior for Fe2O3 and the charge storage mechanism

Previous work demonstrates that Fe2O3 is a promising negative electrode material. Its biochemical performance is strongly influenced by the morphology. Hence, Fe2O3 with nanoparticles, nanosheets and nanorods morphologies are synthesized by hydrothermal method respectively. The relationship between morphology and electrochemical property, particularly in terms of specific capacitance and rate capability are investigated. Detail cyclic voltammetry analysis reveals that the relative contributions of surface capacitive and inner intercalation capacitance change with the morphology. Different contribution of surface relative to inner charge storage leads to different specific capacitance and rate capability. Additionally, Fe2O3 nanosheets delivers a remarkable specific capacitance of 279.9 F g−1 (419.8 mF cm−2) at the scan rate of 5 mV s−1 ascribing to the inner intercalation effect. Moreover, electrochemical tests in neutral and alkaline solution show that the capacitive behavior of Fe2O3 is closely related to the potential window and different electrolyte leads to different contribution of surface relative to inner charge storage. These studies should be useful for elucidating the mechanism and morphological effects on charge storage for Fe2O3-based electrode and provide a direction to enhance its capacitance.

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