Magnetic Properties of Metastable Lithium Iron Oxides Obtained by Solvothermal/Hydrothermal Reaction

The magnetic properties of metastable lithium iron oxides obtained by solvothermal ion-exchange and mixed-alkaline hydrothermal reactions have been examined. Fe2+-containing Li1−xFe5+xO8with inverse spinel structure have been obtained from a mixture of LiCl andα-NaFeO2by solvothermal reaction. The phase has spontaneous magnetization at 300 K and decompose readily by heating at 400°C in air. Metastable layered LiFeO2with a small amount ofα-LiFeO2could be obtained fromα-FeOOH and KOH–LiOH mixed-alkaline solution by hydrothermal reaction. The layered polymorph exhibited antiferromagnetic behavior (TN=20 K) but no spin-glass-like behavior, as observed previously for LiNiO2.