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

[Display omitted] • Energy-storage performance of CuFe(P 2 O 7) was optimized by tuning the ionic ratio. • CFP-4 electrodes' uneven porous structures are driven by abundant metal ions. • Optimized CFP-4 electrodes deliver excellent C A of 1609 mF cm−2 at 3 mA cm−2. • CuFe(P 2 O 7) exhibited good long-term durability of 70 % over 5000 GCD cycles. • CFP// AC asymmetric device yields an ED of 20.62 µWh kg−1 and a PD of 3750 µW kg−1. In this study effects of different precursor concentrations on the microstructural and electrochemical properties of hydrothermally deposited CuFe(P 2 O 7) electrodes are investigated. The X-ray diffraction observations confirm the formation of the CuFe(P 2 O 7) phase. The optimum CuFe(P 2 O 7) 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(P 2 O 7) 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. [ABSTRACT FROM AUTHOR]