Theory and high-throughput discovery of new electride materials

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 general 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 for identifying electrides that only relies on knowledge of the composition and crystal structure. Applying our workflow to the ~55,000 materials in the Materials Project crystal structure database, we identified ~3,000 potential (mostly new) electrides. Analysing these candidate systems with first-principles electronic structure calculations, we find that ~50% of them (~1,500 materials) indeed possess interstitial electrons.