Journal of Power Sources, Vol.313, 81-90, 2016
Density functional theory study of LiFeTiO4
Electrochemical characteristics of spinel cubic LiFeTiO4 are evaluated through Density Functional Theory (DFT) study. Li+ intercalation/de-intercalation behavior of LiFeTiO4 is studied in accordance to the electrochemical relation; LiFeTiO4+Li -> Li2FeTiO4 and LiFeTiO4-0.5Li -> Li0.5FeTiO4 respectively. Effect of Li+ ion exchange on geometrical and electronic structure in terms of volume strain and density of states are respectively studied. It is found that there would be 4% volume strain in charge-discharge cycle accompanying 1.5 Li+ ions exchange per cycle producing high structural rigidity and hence electrochemical safety. The intercalation/de-intercalation voltages are estimated to be 2.6 V and 3.7 V respectively, and are in accordance with earlier experimental reports. The redox active couple corresponding to the intercalation reaction is identified to be Fe+3/Fe+2 while those corresponds to the de-intercalation reaction are identified to be Fe+3/Fe+(3+delta) and O-2/O-2+gamma. The electrochemical capacity is estimated to be 230 mA h g(-1) per cycle enabling 1.5 Li+ exchange. (c) 2016 Elsevier B.V. All rights reserved.
Keywords:Li ion battery;LiFeTiO4;Density functional theory;Volume strain;Density of states;Intercalation/de-intercalation voltage