Defect physics in complex energy materials

TL;DR

This review discusses recent advances in understanding defect physics in complex energy materials, especially battery cathodes, using first-principles calculations to predict defect behavior and guide material design.

Contribution

It provides a comprehensive overview of computational approaches for defect analysis in complex materials, serving as both a review and a methodological guide.

Findings

Predicts defect landscapes under various synthesis conditions

Uncovers mechanisms for electronic and ionic conduction

Guides defect-controlled synthesis and doping strategies

Abstract

Understanding the physics of structurally and chemically complex transition-metal oxide and polyanionic materials such as those used for battery electrodes is challenging, even at the level of pristine compounds. Yet these materials are also prone to and their properties and performance are strongly affected or even determined by crystallographic point defects. In this review, we highlight recent advances in the study of defects and doping in such materials using first-principles calculations. The emphasis is on describing a theoretical and computational approach that has the ability to predict defect landscapes under various synthesis conditions, provide guidelines for defect characterization and defect-controlled synthesis, uncover the mechanisms for electronic and ionic conduction and electrochemical extraction and (re-)insertion, and provide an understanding of the effects of doping. Though applied to battery materials here, the approach is general and applicable to any materials in which the defect physics plays a role or drives the properties of interest. Thus, this work is intended as an in-depth review of defect physics in particular classes of materials, but also as a methodological template for the understanding and design of complex functional materials.