High capacity NbS2-based anodes for Li-ion batteries

Abstract

We have investigated the lithium capacity of the 2H phase of niobium sulphide (NbS2) using density functional theory calculations and experiments. Theoretically, this material is found to allow the intercalation of a double layer of Li in between each NbS2 layer when in equilibrium with metal Li. The resulting specific capacity (340.8 mAh/g for the pristine material, 681.6 mAh/g for oxidized material) can reach more than double the specific capacity of graphite anodes. The presence of various defects leads to an even higher capacity with a partially reversible conversion of the material, indicating that the performance of the anodes is robust with respect to the presence of defects. Experiments in battery prototypes with NbS2-based anodes find a first specific capacity of about 1,130 mAh/g, exceeding the theoretical predictions.