Electrochemical investigations of B-site modified La₂BMnO₆ (B = Ni, Co, Fe) electrospun fibers for supercapacitor performance

Abstract Perovskite oxides have attracted attention in recent years owing to their superior electrochemical performance. Here, we report the series of single-phase double perovskite oxides fibers of La 2 NiMnO 6 , La 2 CoMnO 6 and La 2 FeMnO 6 using a simple sol–gel assisted electrospinning method and its application in supercapacitors, investigated first time. The crystal structure, functional groups and fibrous morphology were investigated using x-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and High-Resolution Scanning Electron Microscopy (HRSEM-EDAX). The Goldschmidt tolerance factor and cell parameters were refined using Rietveld refinement program. The synthesized fibers presented an unfragmented network of thickness in the range of 200–380 nm. The electrochemical performance of electrodes were elucidated using three-electrode system in 3 M KOH. The specific capacitances of La 2 NiMnO 6 , La 2 CoMnO 6 and La 2 FeMnO 6 electrodes were 1272 F g −1 , 1048 F g −1 and 238 F g −1 at 4 mA g −1 . The Nyquist plots of La 2 NiMnO 6 and La 2 CoMnO 6 electrode displayed the sloping line in low frequency and a semicircle in the high frequency region while La 2 FeMnO 6 electrode experienced a flat line which was observed due to large internal resistance of Fe. Among the synthesized fibers, La 2 NiMnO 6 electrode showcased the highest specific capacitance with 87.5% cycling stability after 3000 cycles which shows the better stability of La 2 NiMnO 6 electrode and its use for practical applications.