Phase transformation in wet chemically synthesized Y2NiFeO6, and its magnetic and energy storage properties

In this work we report, the structural, magnetic, and energy storage properties of double perovskite oxide Y 2 NiFeO 6 synthesized via wet chemical sol–gel process. The amorphous phase structure obtained at the synthesis temperature of 650 °C, turned to mixed cubic-hexagonal phase of Y 2 NiFeO 6 at 850 °C, and subsequently to thermally stable mixed cubic-orthorhombic phase at and above the temperature of 950 °C. The X-ray photoelectron spectra of thermally stable phase of Y 2 NiFeO 6 exhibited the presence of yttrium in Y 3+ state, nickel in Ni 2+ /Ni 3+ state and iron in Fe 3+ state. The Y 2 NiFeO 6 exhibited room temperature ferromagnetic behavior with Curie temperature at or above the room temperature. The highest specific capacitance achieved via cyclic voltammetry in three-electrode system was 74.10 F/g at the scan rate of 5 mV/s. It has remarkable specific capacitance retention of ~ 95% after 5000 chargingdischarging cycles at the current density of 6 A/g. The energy storage parameters i.e., energy density and power density were ~ 3.93 Wh/kg and ~ 810.03 Wkg −1 , respectively at current density of 1 A g −1 . Graphic abstract