First-Principles Study of Three-Dimensional Electrides Containing One-Dimensional [Ba₃N]³⁺ Chains

Abstract

Electrides, a unique type of compound where electrons act as anions, have a high electron mobility and a low work function, which makes them promising for applications in electronic devices and high-performance catalysts. The discovery of novel electrides and the expansion of the electride family have great significance for their promising applications. Herein, we reported four three-dimensional (3D) electrides by coupling crystal structure database searches and first-principles electronic structure analysis. Subnitrides (Ba 3 N, LiBa 3 N, NaBa 3 N, and Na 5 Ba 3 N) containing one-dimensional (1D) [Ba 3 N] 3+ chains are identified as 3D electrides for the first time. The anionic electrons are confined in the 3D interstitial space of Ba 3 N, LiBa 3 N, NaBa 3 N, and Na 5 Ba 3 N. Interestingly, with the increase of Na content, the excess electrons of Na 5 Ba 3 N play two roles of metallic bonding and anionic electrons. Therefore, the subnitrides containing 1D [Ba 3 N] 3+ chains can be regarded as a new family of 3D electrides, where anionic electrons reside in the 3D interstitial spaces and provide a conduction path. These materials not only are experimentally synthesizable 3D electrides but also are promising to be exfoliated into advanced 1D nanowire materials. Furthermore, our work suggests a discovery strategy of novel electrides based on one parent framework like [Ba 3 N] 3+ chains, which would accelerate the mining of electrides from the crystal structure database.

Multi-dimensional inorganic electrides for energy conversion and storage

“…Third, the cations should be located around the interstitial positions and possess relatively low electronegativity, so that the interstitial positions can successfully capture the excess electrons. Based on the above conditions, currently, inorganic electrides are mainly concentrated in the main group and rare earth elements, such as Ca 2 N, 9 CaF, 28 Gd 2 C, 8,29 Y 5 Si 3 , 21 Sc 2 C, 30 β-Yb 5 Sb 3 , 31,32 Ba 5 P 3 , 33 Ba 3 N 6,34 etc. , as shown in Fig.…”