Lithiation of Copper Selenide Nanocrystals.

The search for ion-conductive solid electrolytes for Li batteries is an important scientific and technological challenge with economic and sustainable energy implications. In this study, nanocrystals (NCs) of the ion conductor copper selenide (Cu Se) were doped with Li by the process of cation exchange. Li Cu Se alloy NCs were formed at intermediate stages of the reaction, which was followed by phase segregation into Li Se and Cu Se domains. Li-doped Cu Se NCs and Li Se NCs exhibit a possible SI phase at moderately elevated temperatures and warrant further ion-conductance tests. These findings may guide the design of nanostructured super-ionic electrolytes for Li transport.