Electrochemical Properties of Ferrous Nickel Pyrophosphate Thin Film Electrodes for Energy Storage Applications

Abstract

The present work deals with the preparation of ferrous nickel pyrophosphate (Fe2Ni2P2O7) thin films via a facile approach namely chemical bath deposition. X-ray diffraction analysis evinces that the prepared Fe2Ni2P2O7 thin films are of monoclinic structure and crystallinity is improved by increase in Fe concentration with a preferential orientation along the (111) direction. Scanning electron microscopy and high-resolution scanning electron microscopy analysis reveal the microsphere like morphology and uniform anchoring of Fe2 on Ni2P2O7 thin film surface, which is favorable for good charge transfer between the electrode and electrolyte interface. The UV-Visible spectroscopy analysis reveals that direct optical band gap of Fe2Ni2P2O7 thin films holds decreasing trend from 3.80 eV to 3.17 eV with increasing amount of Fe from 1M to 3M. Photoluminescence spectroscopy has been employed to study the luminescence properties, with respect to the Fe concentration. The different phonon modes and magnon modes of vibration present in the Fe2Ni2P2O7 film have been studied by Raman spectroscopy. Electrochemical analysis shows that, the Fe2Ni2P2O7 film electrode offers a specific capacitance of 441 F/g with excellent electrochemical and cyclic stability. The studies on Fe2Ni2P2O7 films have yielded promising results enrich express the potentiality for better utilization in energy storage devices.