Novel fast Li-ion conductors for solid-state electrolytes from first-principles

TL;DR

This study employs high-throughput computational screening to identify and analyze new fast lithium-ion conductors for solid-state electrolytes, highlighting promising materials like Li7NbO6 with high ionic conductivity.

Contribution

The paper introduces a novel automated screening protocol combining first-principles calculations and molecular dynamics to discover and evaluate new solid-state electrolyte materials.

Findings

Li7NbO6 exhibits ~5 mS/cm ionic conductivity at room temperature

Approximately 60 promising new conductors identified and analyzed

A self-consistent workflow improves the accuracy of the pinball model

Abstract

We present a high-throughput computational screening for fast lithium-ion conductors to identify promising materials for application in all solid-state electrolytes. Starting from more than 30,000 Li-containing experimental structures sourced from Crystallography Open Database, Inorganic Crystal Structure Database and Materials Platform for Data Science, we perform highly automated calculations to identify electronic insulators. On these ~1000 structures, we use molecular dynamics simulations to estimate Li-ion diffusivities using the pinball model, which describes the potential energy landscape of diffusing lithium with accuracy similar to density functional theory while being 200-500 times faster. Then we study the ~60 most promising and previously unknown fast conductors with full first-principles molecular dynamics simulations at several temperatures to estimate their activation barriers. The results are discussed in detail for the 9 fastest conductors, including $Li_7NbO_6$ which shows a remarkable ionic conductivity of ~5 mS/cm at room temperature. We further present the entire screening protocol, including the workflows where the accuracy of the pinball model is improved self-consistently, necessary to automatically running the required calculations and analysing their results.