Crystallographic design of intercalation materials

TL;DR

This review discusses how crystallographic design can improve the durability and performance of intercalation materials used in energy storage by addressing structural transformations, microstructures, and defects.

Contribution

It provides a comprehensive overview of crystallographic factors affecting intercalation materials and identifies design strategies to enhance their properties and lifespan.

Findings

Structural transformations cause lattice strains leading to material failure.

Crystallographic texture influences ion transport and phase microstructures.

Designing crystallographic features can mitigate degradation and improve durability.

Abstract

Intercalation materials are promising candidates for reversible energy storage and are, for example, used as lithium-battery electrodes, hydrogen-storage compounds, and electrochromic materials. An important issue preventing the more widespread use of these materials is that they undergo structural transformations (of up to ~10% lattice strains) during intercalation, which expand the material, nucleate microcracks, and, ultimately, lead to material failure. Besides the structural transformation of lattices, the crystallographic texture of the intercalation material plays a key role in governing ion-transport properties, generating phase separation microstructures, and elastically interacting with crystal defects. In this review, I provide an overview of how the structural transformation of lattices, phase transformation microstructures, and crystallographic defects affect the chemo-mechanical properties of intercalation materials. In each section, I identify the key challenges and opportunities to crystallographically design intercalation compounds to improve their properties and lifespans. I predominantly cite examples from the literature of intercalation cathodes used in rechargeable batteries, however, the identified challenges and opportunities are transferable to a broader range of intercalation compounds.