Synthesis of Lithium Oxide Composite Nanoparticles with Spinel Structure by Induction Thermal Plasma

Lithium oxide composite nanoparticles were successfully synthesized by induction thermal plasma. Powder mixtures of Li$_{2}$CO$_{3}$ and MnO$_{2}$ were injected into the induction thermal plasma at 20 kW-4MHz operated in different O$_{2\, }$gas flow rates. The injected precursors were evaporated immediately in the high temperature region of the plasma and nanoparticles were produced through the quenching process. The particles were characterized by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained results indicated that the nanoparticles of LiMn$_{2}$O$_{4}$ and LiMnO$_{2}$ were selectively synthesized by controlling partial pressure of O$_{2}$ in thermal plasma. Then formation mechanism of Li-based oxide nanoparticles was investigated on the basis of homogenous nucleation rate and thermodynamic consideration. In higher partial pressure of O$_{2}$, MnO nucleates and Li oxide condense on the nuclei with relatively high condensation rate, resulting in single-phase LiMn$_{2}$O$_{4}$ formation. On the other hand, in lower partial pressure of O$_{2,\, }$LiMnO$_{2}$ was obtained due to the lower condensation rate of Li oxide.