Preparation and magnetic performance of Co 0.8 Fe 2.2 O 4 by a sol–gel method using cathode materials of spent Li-ion batteries

Abstract Spinel-structured Co 0.8 Fe 2.2 O 4 was synthesized through a sol–gel method using the cathode materials of spent Li-ion batteries as raw materials and ethylene glycol as a gelling agent. The effect of preparation conditions on the microstructure and some magnetic properties was investigated via X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The preparation process had a significant effect on the performance and structure of the cobalt ferrite. An ethylene glycol to metal ion ratio, calcination temperature, and calcination time of 0.8:1, 800 °C, and 6 h, respectively, constituted the optimum conditions for preparation of the Co 0.8 Fe 2.2 O 4 . Moreover, Co 0.8 Fe 2.2 O 4 exhibited a saturated magnetization of up to 61.96 emu g −1 . The results presented here indicate a new effective means for the preparation of cobalt ferrite materials.