First principles study of layered transition metal dichalcogenides for use as electrodes in Li-ion and Mg-ion batteries

Abstract

We present a first principles investigation of lithium- and magnesium-intercalation into each of the layered transition metal dichalcogenides. Using a consistent and thorough methodology, we investigate 84 TMDC materials (transition metals, Group XIV, and S, Se, Te chalcogens) as potential electrode materials, evaluating their T and H phases. We show generally low volume expansions and provide direct estimates of the theoretical capacity based on thermodynamic arguments. We find that many offer capacities in excess of 200 mA h g⁻¹ (400 mA h g⁻¹) with Li (Mg) intercalation and show a range of voltage profiles. For both Li and Mg, we show that the Group VIII and IX are promising electrode materials, and in particular highlight ScS₂ as a promising cathode material. We also show that sulfides are generally better for electrode materials.