Electrides are materials with electrons localized on interstitial sites in the crystal lattice and exhibit an array of interesting properties that show promise for applications such as catalysts, electron emitters and superconductors. Electrides can be found among many different classes of materials, including elemental metals at high pressure, organic crystals, intermetallic compounds and ceramic materials.
In this work, we present a theory that provides a unified understanding of the origin of interstitial electrons in all currently known types of electrides. Using this theoretical understanding, we have devised an automated high-throughput algorithm based on first-principles electronic structure calculations for identifying systems that are potentially electrides. Applying our workflow to the ~55,000 materials in the Materials Project crystal structure database, we identified ~10,000 potential candidates. These candidate systems demonstrate a smooth transition from the typical (inter)metallic systems to prototypical electride systems and our method can be used to quantitatively measure the likelihood of a system being identified as an electride.