Designing Superionic Conductors Using Tetrahedrally Packed Structures

TL;DR

This paper introduces a new design principle for superionic conductors based on tetrahedrally packed structures, enabling the discovery of materials with potentially higher ionic conductivities for energy storage.

Contribution

It extends the traditional BCC framework principle by identifying TP structures as promising for ionic conduction and proposes the Met2Ion method for generating new ionic crystal structures.

Findings

TP frameworks are prevalent in Ag-ion conductors.

First-principles simulations show potential for high ionic conductivity.

The Met2Ion method facilitates discovery of new ionic conductors.

Abstract

In the pursuit of advanced energy storage solutions, the crystal structure of ionic conductors plays a pivotal role in facilitating ion transport. The conventional structural design principle that compounds with the body-centered cubic (BCC) anionic frameworks have high ionic conductivity is well known. We have extended the conventional design principle by uncovering that many of the anionic frameworks of Ag-ion conductors are characterized by tetrahedrally packed (TP) structures. Leveraging our findings, we have virtually screened TP framework compounds, uncovering their intrinsic potential for superior ionic conductivity through first-principles molecular dynamics simulations. Our design principle is applicable to Ag$^+$ and other mobile ions, including Li$^+$ and F$^-$. We proposed the Met2Ion method to generate ionic crystal structures using metal crystal structures as templates and demonstrated that new ionic conductors with TP frameworks can be discovered. This work paves the way for the discovery and development of next-generation energy storage materials with enhanced performance.