Article Cite This: ACS Appl. Energy Mater. 2018, 1, 464−474
www.acsaem.org
One-Dimensional BiFeO3 Nanowire-Reduced Graphene Oxide Nanocomposite as Excellent Supercapacitor Electrode Material Debabrata Moitra, Chayan Anand, Barun Kumar Ghosh, Madhurya Chandel, and Narendra Nath Ghosh* Nano-Materials Lab, Department of Chemistry, Birla Institute of Technology and Science, Pilani K.K. Birla Goa Campus, Goa 403726, India
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S Supporting Information *
ABSTRACT: In this work, we have reported a nanocomposite, composed of a BiFeO3 nanowire and reduced graphene oxide (BFO-RGO), as an electrode material for a high-performance supercapacitor. A facile hydrothermal method was employed to prepare BFO-RGO nanocomposite. The electrochemical measurements were performed by cyclic voltammetry, galvanostatic charge/ discharge measurements, and electrochemical impedance spectroscopy. The specific capacitance of the BFO-RGO nanocomposite was 928.43 F g−1 at current density 5 A g−1, which is superior to that of pure BiFeO3. Additionally, this nanocomposite shows good cyclic stability, and ∼87.51% of specific capacitance is retained up to 1000 cycles. It also exhibits a high charge density of 18.62 W h kg−1 when the power density is 950 W kg−1. These attractive results suggest the potential of BiFeO3 nanowire-RGO nanocomposite as an active material for the construction of a high-performance supercapacitor electrode. To the best of our knowledge, this is the first time the application of BiFeO3 nanowire-RGO nanocomposite as a supercapacitor has been reported. KEYWORDS: BiFeO3 nanowire-reduced graphene oxide, hydrothermal method, electrochemical properties, specific capacitance, capacity retention principle of EDL electrodes.3,8,13,21 On the other hand, charge storage occurs at the pseudocapacitor electrode by the fast reversible faradaic reactions.1 Carbon-based materials are generally used to construct EDL electrodes.8,21 Recently, EDL electrodes are used in some commercial applications, such as emergency doors on an Airbus A380, etc.21 However, the lower energy density of EDL electrodes than the batteries limits their optimal discharge time to less than a minute.1 This factor limits the wide application of EDL electrodes. Transition metal oxides and conducting polymers are commonly used as the active materials in pseudocapacitive electrodes.1,22,23 Metal oxides, such as RuO2, Fe3O4, and MnO2, have been wellstudied as pseudocapacitors.8,24−30 RuO2 shows relatively high specific capacitance of more than 600 F g−1 in an aqueous electrolyte. However, the high cost of RuO2 limits its application.1 MnO2 shows specific capacitance of ∼150 F g−1 in the neutral aqueous electrolyte with a voltage window of
