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 2−y Se) were doped with Li by the process of cation exchange. Li 2x Cu 2−2x Se alloy NCs were formed at intermediate stages of the reaction, which was followed by phase segregation into Li 2 Se and Cu 2 Se domains. Li‐doped Cu 2−y Se NCs and Li 2 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.