Impact of ZnFe₂O₄ nanoparticles parameters on magnetic and electrochemical performance

Nanostructured ZnFe2O4 powder with crystallite size from 4 to 55 nm was synthesized via coprecipitation method followed by calcination process carried out at different temperatures. The obtained samples were characterized by XRD, SEM, XPS and ICP-AES methods; magnetic properties at 298 and 77 K were measured and analyzed, the electrochemical behavior of anode materials was tested. The Fe - Zn ratio and oxygen vacancies amount were established. It was found that the magnetization values depend on the crystallite size, and the Fe - Zn ratio determine magnetic performance of the samples in the case of field cooling curves. The sample calcined at 500 degree celsius showed the highest Coulombic efficiency of 76.2 % (at the first cycle) and initial discharge and charge specific capacity of 1400 and 1067 mAh center dot g(-1) at current densities of 0.2 A center dot g(-1). Also, it was demonstrated that the initial capacity depends on oxygen vacancies amount, the highest specific capacity value was for sample with crystallite size 46.9 nm and with a smallest oxygen vacancies amount.