Fabrication of high-performance metal ion doped iron oxide electrode for supercapacitor applications through a novel platform

Abstract

We provide a novel electrodeposition platform of undoped and Eu3+ doped iron oxide nanoparticles (Eu-IONPs) from an additive-free electrolyte containing Fe(NO3)3, FeCl2 and EuCl3. The prepared IONPs were analyzed using x-ray diffraction, field emission electron microscopy and energy-dispersive x-ray techniques, and the obtained data showed successful electrosynthesis of magnetite nanoparticles (size ≈ 10 nm) doped with about 10 wt% Eu3+ ions. The Eu-IONPs were used as supercapacitor electrode materials, and characterized by cyclic voltammetry and galvanostatic charge–discharge measurements. The as-synthesized Eu-IONPs exhibit remarkable pseudocapacitive activities including high specific capacitances of 212.5 and 153.2 F g−1 at 0.5 and 2 A g−1, respectively, and excellent cycling stabilities of 93.9% and 86.5% after 2000 discharging cycles. Furthermore, vibrational sample magnetometer data confirmed better superparamagnetic performance of Eu-IONPs (Ms = 72.8 emu g−1, Mr = 0.24 emu g−1 and HCi = 3.48 G) as compared with pure IONPs (Ms = 51.92 emu g−1, Mr = 0.95 emu g−1 and HCi = 14.62 G) due to exhibiting lower Mr and HCi values. This novel synthetic platform of metal ion doped iron oxide is potentially a convenient way to fabricate high-performance iron oxide electrodes for energy storage systems.