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

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 (Ba3N, LiBa3N, NaBa3N, and Na5Ba3N) containing one-dimensional (1D) [Ba3N]3+ chains are identified as 3D electrides for the first time. The anionic electrons are confined in the 3D interstitial space of Ba3N, LiBa3N, NaBa3N, and Na5Ba3N. Interestingly, with the increase of Na content, the excess electrons of Na5Ba3N play two roles of metallic bonding and anionic electrons. Therefore, the subnitrides containing 1D [Ba3N]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 [Ba3N]3+ chains, which would accelerate the mining of electrides from the crystal structure database.