Hydride Ion Intercalation and Conduction in the Electride Sr$_3$CrN$_3$

TL;DR

This study uses density functional theory to demonstrate that Sr₃CrN₃, a one-dimensional electride, exhibits exceptional hydride ion conduction with a very low diffusion barrier, making it promising for energy storage and gas separation.

Contribution

The paper reveals that Sr₃CrN₃ is a highly effective hydride conductor with the lowest diffusion barrier among known materials, highlighting its potential for ion-transport applications.

Findings

Diffusion barrier as low as 0.30 eV

Estimated diffusion coefficient of 5.37×10⁻⁸ cm²/s

Transition from metal to insulator upon hydride incorporation

Abstract

The electride Sr$_3$CrN$_3$ has a one-dimensional channel of electron density, which is a rare feature that offers great potential for fast ion conduction. Using density functional theory, we find that Sr$_3$CrN$_3$ is an excellent hydride conductor within this channel, with a diffusion barrier as low as 0.30 eV and an estimated diffusion coefficient of $5.37\times 10^{-8}$ cm$^2$/s. This diffusion barrier is lower than those reported for the best hydride conductors to date. We also show the most-stable amount of hydride in the host material under standard conditions and the corresponding change in electronic structure from metal to wide-gap insulator. Our results highlight the potential offered by 1D electride materials for ion-transport applications such as energy storage or gas separation.