Density functional theory study of LiFeTiO4

• LiFeTiO4 exhibits 4% volume strain accompanying 1.5 Li+ exchange in a cycle.
• Mott-Hubbard and charge-transfer insulator type band-gap exist in LiFeTiO4.
• Estimated voltage plateaus are 2.6 V and 3.7 V.
• The redox active couple are Fe+3/Fe+2 and Fe+3/Fe+(3+δ), O−2 → O−2+γ for the plateaus.

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+δ) and O−2/O−2+γ. The electrochemical capacity is estimated to be 230 mA h g−1 per cycle enabling 1.5 Li+ exchange.