Li-containing Oxide Nanopowders Prepared by the Plasma Chemical Synthesis

Abstract

Plasma chemical synthesis is used to obtain lithium – transition metal (Co, Mn, Ni) oxide powders, which can be applied as cathode materials for Li-ion secondary batteries. Evaporation of raw powder mixtures (Li2CO3+Co or (Mn2O3+MnO2) or Ni) in air or nitrogen RF-IC plasma flow, subsequent quenching with air and condensation of products results in formation of nanopowders with SSA of 14 – 24 m2/g. Prepared powders are investigated by XRD, BET, DTA methods and wet chemical analysis. In dependence on corresponding raw powder mixture composition, plasma forming gas and consumption of quenching gas LiCoO2, LiMn2O4, Li2MnO3, Li2Ni8O10 compounds and admixture phases of Co3O4, NiO and in all cases LiNO3·nH2O are formed in nanopowders. To avoid from humidity and formation of lithium nitrate additional heating of powders is needed. After heating at 600 – 1000 °C pure lithium cobaltate LiCoO2 (initial molar ratio Li/Co = 1.0) and spinel LiMn2O4 (initial molar ratio Li/Mn = 0.5) with good crystallinity and average particle size of 66 – 105 nm are prepared.