Lithiation of Copper Selenide Nanocrystals

Abstract

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 (Cu2−ySe) were doped with Li by the process of cation exchange. Li2xCu2−2xSe alloy NCs were formed at intermediate stages of the reaction, which was followed by phase segregation into Li2Se and Cu2Se domains. Li‐doped Cu2−ySe NCs and Li2Se 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.