Improving the energy-storage performance of bimetallic pyrophosphate CuFe(P2 O7) electrodes by tuning ionic ratios

Abstract

In this study effects of different precursor concentrations on the microstructural and electrochemical properties of hydrothermally deposited CuFe(P2 O7) electrodes are investigated. The X-ray diffraction observations confirm the formation of the CuFe(P2 O7) phase. The optimum CuFe(P2 O7) electrode displays an excellent capacitance of 1609 mF cm−2 (192.84 F g−1) at 3 mA cm−2 with excellent energy and power densities. Moreover, the best electrode exhibits a high diffusion coefficient of 4.527 × cm3 S−1 × 10−7 with b-value of 0.62 and sustains 70 % stability over 5000 cycles. Constructed asymmetric supercapacitor device yields an energy density of 20.62 µWh kg−1 and power density of 3750 µW kg−1 with noteworthy retention of 67 % over long-term 10,000 cycles. The encouraging electrochemical activity of CuFe(P2 O7) can be correlated with alterations in chemical states, and high electrochemical active surface area which offer more accessible sites with enhanced electrical conductivity, efficient electron transportation. © 2024 Elsevier B.V.