Enhancing electrochemical performance and magnetic properties of FeVO4 nanoparticles by Ni-doping: The role of Ni contents

The Fe1-xNixVO4 (where x = 0, 0.05, 0.1, and 0.2) nanoparticles in this work were successfully synthesized via a co-precipitation method. The structural, magnetic and electrochemical properties of the prepared Fe1-xNixVO4 nanoparticles were studied as a function of Ni content. The experimental results show that the prepared Ni-doped FeVO4 samples have a triclinic structure. Scanning electron microscopy (SEM) images reveal a decrease in average nanoparticle size with increasing Ni content, leading to an enhancement in both specific surface area and magnetization values. X-ray absorption near edge structure (XANES) analysis confirms the substitution of Ni²⁺ ions into Fe³⁺ sites. The magnetic investigation reveals that Ni-doped FeVO4 exhibits weak ferromagnetic behavior at room temperature, in contrast to the antiferromagnetic behavior observed in the undoped FeVO4. Electrochemical studies demonstrate that the Fe0.95Ni0.05VO4 electrode achieves the highest specific capacitance of 334.05 F/g at a current density of 1 A/g, which is attributed to its smallest average pore diameter. On the other hand, the enhanced specific surface of the Fe0.8Ni0.2VO4 electrode is responsible for its outstanding cyclic stability. Overall, our results suggest that the magnetic and electrochemical properties of FeVO4 nanoparticles could be effectively tuned by varying Ni doping contents.