Li–Ni–Mn-oxide nanoparticle synthesis by induction thermal plasmas for lithium ion battery electrode

Abstract

Synthesis of lithium nickel manganese oxide (LNMO) nanoparticles was performed by induction thermal plasmas. The change in the crystal structure of the LNMO nanoparticles was confirmed with the substitution of a part of Mn of the lithium nickel oxide nanoparticles with Ni. The formation mechanism of the nanoparticle crystal structure was investigated based on nucleation theory and thermodynamic considerations. The synthesized LNMO nanoparticles formed two crystal structures of cubic rock salt type Li_0.4Ni_1.2Mn_0.4O₂ (space group Fm3m) of non-stoichiometry and cubic spinel type LiNi_0.5Mn_1.5O₄ (space group Fd3m). The cubic rock salt structure nanoparticles are easily formed when the molar ratio of Mn and (Ni + Mn) is taken as 0.25. The cubic spinel structure nanoparticles are easily formed when the Mn/(Ni + Mn) molar ratio is 0.875. The formation mechanism of the LNMO was generated by condensation of MnO and Li₂O after nucleation of NiO. This report investigated the effect of the crystal structure and formation mechanism of the LNMO nanoparticles by varying the molar ratio of Ni and Mn formed by induction thermal plasma.