Electrical and lithium ion dynamics in Li2IrO3 from density functional theory study

Abstract

Layered Li₂IrO₃ has been investigated using first-principles calculations within the GGA and GGA + U schemes. Within the GGA + U approach, the calculated intercalation voltage (ranging from 3.2 V to 4.1 V) is found to be in good agreement with experiments. Electronic-structure analysis shows that the band gap of pure phase Li₂IrO₃ is ∼1 eV, which is indicative of semiconductor properties. Moreover, further studies of lithium diffusion in bulk Li₂IrO₃ show that unlike the two dimensional diffusion pathways in rock salt structure layered cathode materials, lithium can diffuse in a three-dimensional pathway in Li₂IrO₃, with moderate lithium migration energy barriers ranging from 0.24 to 0.81 eV.