Electrochemical behavior of SrFe12O19/CoFe2O4 composite nanoparticles synthesized via one-pot hydrothermal method

Abstract

SrFe12O19/CoFe2O4 composite nanoparticles were successfully synthesized by a one-pot hydrothermal route and the structural and morphological properties were studied in details. The XRD pattern results confirmed SrFe12O19/CoFe2O4 composite formation at Co/Sr ratio of 0.5 with some residual second phases of SrCO3 and Fe2O3. FTIR spectra showed the strong absorption bands in the range of 440–650 cm−1, which are related to Fe[sbnd]O bonds. FESEM images illustrated that the Co-ferrite nanoparticles would nucleate on the surface of plate-liked Sr-ferrite particles by increasing of Co/Sr ratio. At the ratio of 0.5, whole surface of Sr-ferrite particles was covered by Co-ferrite nanoparticles. HRTEM images confirmed the SrFe12O19/CoFe2O4 nanocomposite formation with the average particle size of 8 nm at the Co/Sr ratio of 0.5. Cyclic voltammetry suggesting the pseudocapacitance behavior of the samples where the specific capacitance in the potential window of −1.4 -0 V and scan rate of 50 mV s−1 increased from 133 F g−1 in pure Sr-ferrite to 634 F g−1 at the Co/Sr = 0.5. Subsequently, specific capacitance decreased to 275 F g−1 at Co/Sr = 1. These results were also confirmed by galvanostatic charge-discharge (GCD) curves and the effect of variation of the scan rates were evaluated. 79% of the initial capacitance maintains for the sample with Co/Sr ratio of 0.5 after 5000 continuous cyclic voltammetry at the scan rate of 50 mV s−1 which confirms the superior performance of the prepared electrode as a supercapacitor material.