Polyselenide Anchoring Using Transition-Metal Disulfides for Enhanced Lithium-Selenium Batteries.

While selenium has recently been proposed as a lithium battery cathode as a promising alternative to a lithium-sulfur battery, dissolution of intermediate species should be resolved to improve its cycle stability. Here, we report the promising results of transition-metal disulfides as an anchoring material and the underlying origin for preventing active material loss from the electrode using density functional theory calculations. Group 5 and 4 disulfides (VS2, NbS2, TaS2, TiS2, ZrS2, and HfS2) in particular show anchoring capabilities superior to those of group 6 disulfides (CrS2, MoS2, and WS2). The governing interaction controlling the latter relative anchoring strengths is shown to be charge transfer as understood by crystal-field theory. The current findings and methodologies provide novel chemical insight for the further design of inorganic anchoring materials for both lithium-selenium and lithium-sulfur batteries.