Electrochemical energy storage properties of Fe2Ni2P2O7 thin film electrode for future supercapacitor application

Metal phosphates are found to be suitable material in the field of energy storage. The present work deals with preparation of ferrous nickel pyrophosphate (Fe 2 Ni 2 P 2 O 7 ) thin films via chemical bath deposition and the study of their electrochemical performance. Fe 2 Ni 2 P 2 O 7 thin films are of monoclinic structure as revealed by XRD analysis and the crystallinity gets improved with preferential orientation along (111) direction as Fe concentration is increased. The films exhibit like morphology and uniform anchoring of Fe 2 on Ni 2 P 2 O 7 surface favoring good charge transfer between the electrode/electrolyte interface. FNP electrode with 3 M concentration of Fe offers high specific capacitance (501 F/g) with good electrochemical performance with capacitive retention of 81.02% over 6000 cycles. Analysis based on Trasatti and Dunn’s model gives the b value in a range between 0.66 and 0.69 for the FNP electrodes confirming their capacitive as well as diffusive nature. Such a hybrid nature in storage property of Fe 2 Ni 2 P 2 O 7 and the characterization results pose them as promising candidates in energy storage application.