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

Microcrystalline Li/Co ferrite composite of about 0.14 mu m crystallite size has been synthesized successfully by treating a mixture of cathode material of spent lithium-ion batteries and iron oxide at temperatures >= 1000 degrees 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 degrees C) and shorter time (1 h) impure ferrite phase with the presence of unreacted Co-3 O-4 and Fe,03 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. (c) 2006 Elsevier B.V. All rights reserved.