Optimized electrospun MnFe2O4 nanofibers as promising electrode materials for supercapacitor applications: physical and electrochemical properties

Spinel-type MnFe2O4 nanofibers were fabricated using a sol-gel electrospinning technique followed by calcination at different temperatures (400, 500 and 600 degrees C). The resulting products were thoroughly investigated for their physical and electrochemical properties. XRD analysis revealed the presence of a secondary Fe2O3 phase alongside the initial cubic phase for electrospun fibers calcined at 600 degrees C. FESEM images showed that the as-spun fibers calcined at 400 degrees C had a hollow nanofiber morphology, which gradually converted to porous nanofiber with increasing calcination temperature. Optical studies indicated that the optical band gap decreased from 1.53 to 1.34 eV with an increase in calcination temperature. The sample calcined at 500 degrees C exhibited the best magnetic properties with a saturation magnetization of 44.2 emu g(-1) and a coercivity of 73.0 Oe. The electrochemical analysis revealed that the MnFe2O4 nanofibers calcined at 500 degrees C had the superior specific capacitance of 365 F g(-1) at 1 A g(-1) and retained 92.54% of its initial specific capacitance even after 3000 cycles, demonstrating good cycling stability. These results suggest that the MnFe2O4-500 degrees C electrode material is a promising candidate for pseudocapacitor applications.