First Principles Investigation on the Phase Change Induced By Delithiation of Li2Fe0.5Mn0.5SiO4

Wednesday, 27 May 2015
Salon C (Hilton Chicago)
T. Yi, Y. Li, X. Cheng, and Y. Zhang (Xiamen University)
In this work, the phase change induced by the delithiation of Li2Fe0.5Mn0.5SiO4 compound is investigated via the First Principles calculations. Three delithiated states are selected to calculate their formation energies and crystal structures. The calculated results reveal that there is a significant difference in phase structures between the LiFe0.5Mn0.5SiO4 and Li0.5Fe0.5Mn0.5SiO4 compounds with severe volume variation. It is found that the local structures of Li2Fe0.5Mn0.5SiO4 compound is transformed from the corner-sharing tetrahedrons centered by Fe and Mn into the deformed hexahedrons in which Mn and Fe ions are connected to five O ions. The accompanied redox couples are Fe2+/Fe3+, Mn2+/Mn3+, and Mn3+/Mn4+ for the delithiation of Li2Fe0.5Mn0.5SiO4 to Li1.5Fe0.5Mn0.5SiO4, LiFe0.5Mn0.5SiO4, and Li0.5Fe0.5Mn0.5SiO4, respectively.