Temperature- and vacancy-concentration-dependence of heat transport in Li$_3$ClO from multi-method numerical simulations

TL;DR

This paper investigates how temperature and vacancy concentration affect heat transport in Li$_3$ClO using advanced multi-method simulations, revealing the significant roles of anharmonic interactions and defects.

Contribution

It introduces a multi-method approach combining ab initio, machine-learning, and force-field models to accurately study heat transport in ionic conductors, surpassing previous semi-empirical models.

Findings

Anharmonic interactions significantly influence thermal conductivity.

Defects and vacancies play a crucial role in heat transport.

The developed model is applicable to a broad class of ionic conductors.

Abstract

Despite governing heat management in any realistic device, the microscopic mechanisms of heat transport in all-solid-state electrolytes are poorly known: existing calculations, all based on simplistic semi-empirical models, are unreliable for superionic conductors and largely overestimate their thermal conductivity. In this work, we deploy a combination of state-of-the-art methods to calculate the thermal conductivity of a prototypical Li-ion conductor, the Li$_3$ClO antiperovskite. By leveraging ab initio, machine-learning, and force-field descriptions of inter-atomic forces, we are able to reveal the massive role of anharmonic interactions and diffusive defects on the thermal conductivity and its temperature dependence, and to eventually embed their effects into a simple rationale which is likely applicable to a wide class of ionic conductors.