We have prepared Fe3O4/reduced graphene oxide (rGO) hybrid materials via a simple, cost-effective hydrothermal technique in ambient conditions by combining with growth of Fe3O4 NPs with the reduction of graphene oxide in a one-pot synthesis. This hybrid material has been used to fabricate the electrodes of an electrochemical double layer supercapacitor having a specific capacitance of 451 F g-1 at a scan rate of 5 mV s-1. The external magnetic fields have a huge impact on the electrochemical processes which enhance the supercapacitor performance of the magnetic samples. The as-synthesized Fe3O4/rGO hybrid possesses high surface area, and an external magnetic field (0.125 T) allows electrolyte ions to penetrate deeper into the orifices of the electrode surface - i.e. ions can reach extra electrode surface - and thus improves the capacitance. As a result, the hybrid electrode in the presence of such a magnetic field exhibits a specific capacitance (868.89 F g-1) which is 1.93 times higher than that without any magnetic field. In addition, the energy density and power density of the hybrid electrode in the presence of magnetic field are noticeably improved to 120.68 Wh kg-1 and 3.91 kW kg-1, respectively. These findings suggest a potential revolution to improve the capacitance of traditional supercapacitors significantly in the presence of external magnetic fields, without material replacement.
|Journal||Journal Physics D: Applied Physics|
|State||Published - 9 Aug 2018|
Bibliographical noteFunding Information:
This work was financially supported by department of science and technology (DST), government of India through Ramanu-jan fellowship scheme (SR/S2/RJN-98/2011), DST-FIST (SR/FST/PSI-188/2013) and Presidency University through the FRPDF scheme. SP, SM and SB acknowledge the SPMS Division of Saha Institute of Nuclear Physics for technical and financial support. S P is also thankful to Department of Physics of Raidighi College. The authors would like to thank Dr R Saha of Jadavpur University for the BET measurement help.
© 2018 IOP Publishing Ltd.
- FeO/rGO hybrid
- cation intercalation/de-intercalation
- high energy density
- long cycle life
- magnetic field induced capacitance enhancement