Counting Electrons in Electrides.

The selection and design of charge integration methods remain an outstanding challenge in materials chemistry. In complex materials like electrides, this challenge is amplified by the small charge and complex shape of electride wave functions. For these reasons, popular integration methods, such as the Bader method, usually fail to assign any charge to the bare electrons in an electride.

Assessing ternary materials for fluoride-ion batteries.

Although lithium-ion batteries have transformed energy storage, there is a need to develop battery technologies with improved performance. Fluoride-ion batteries (FIBs) may be promising alternatives in part due to their high theoretical energy density and natural elemental abundance. However, electrode materials for FIBs, particularly cathodes, have not been systematically evaluated, limiting rapid progress.

ScC, a 2D Semiconducting Electride.

Electrides are exotic materials that typically have electrons present in well-defined lattice sites rather than within atoms. Although all known electrides have an electropositive metal cation adjacent to the electride site, the effect of cation electronegativity on the properties of electrides is not yet known. Here, we examine trivalent metal carbides with varying degrees of electronegativity and experimentally synthesize ScC.

First-Principles Prediction of Electrochemical Electron-Anion Exchange: Ion Insertion without Redox.

It is widely assumed that the gain or loss of electrons in a material must be accompanied by its reduction or oxidation. Here, we report a system in which the insertion/deinsertion of an electron occurs without any reduction or oxidation. Using first-principles methods, we demonstrate this effect in the YCF-[YC](e) material system, where (e) indicates a lattice site containing a bare electron.

Bonding in 2D Donor-Acceptor Heterostructures.

The ability to alter distances between atoms is among the most important tools in materials design. Despite this importance, controlling the interlayer distance in stacks of 2D materials remains a challenge. Here we show from first-principles that stacking electrenes-a new class of electron-donating 2D materials-with other 2D materials provides this control.