Synthesis, Structure and Electrochemical Properties of Layered Lithium-Manganese-Iron-Oxide with Mixed Stacking States

Abstract

The layered material, Li_2/3[Mn_1/3Fe_2/3]O₂, was prepared by Li-ion-exchange reactions in alcohols from the host, Na_2/3[Mn_1/3Fe_2/3]O₂. The structure of the stacking sequence was determined by the simulation of X-ray diffraction patterns and its electrochemical properties were characterized. The stacking sequence of the products depended on the reaction temperature and time. The structure of Li_2/3[Mn_1/3Fe_2/3]O₂ obtained 85°C has stacking faults including the O3, O2 and P2-type with the ratio of 4 / 4 / 2. Higher reaction temperatures and longer reaction time yielded the O3-type stacking. The electrochemical properties of Li_2/3[Mn_1/3Fe_2/3]O₂ were clarified using lithium cells.