Synthesis, characterization and magnetic properties of microcrystalline lithium cobalt ferrite from spent lithium-ion batteries

Microcrystalline Li/Co ferrite composite of about 0.14 μm crystallite size has been synthesized successfully by treating a mixture of cathode material of spent lithium-ion batteries and iron oxide at temperatures ≥1000 °C and for ≥4 h firing times. XRD analyses indicate that Li0.5Fe2O4/CoFe2O4 composite is formed. Microstructure investigation using optical microscopy reveals the formation of homogeneous structure with non-uniform size and shape of two ferrite phases. At lower temperature (900 °C) and shorter time (1 h) impure ferrite phase with the presence of unreacted Co3O4 and Fe2O3 phases is detected. It is found that the coercivity (Hc) and saturation magnetization (Ms) values of synthesized Li/Co ferrite composite increased with increasing the firing time and temperature from 153.6 to 177 Oe and from 58.7 to 76.3 emu/g, respectively. Based on the obtained results, the prepared material can be used as a permanent magnet.