LiNiO$_2$ as a high-entropy charge- and bond-disproportionated glass

TL;DR

This paper proposes that LiNiO$_2$, a high-capacity battery cathode, exists as a high-entropy charge-glass state at ambient temperatures, explaining its properties and guiding the design of entropy-stabilized cathodes.

Contribution

It introduces the concept of a high-entropy charge-glass state in LiNiO$_2$ based on electronic structure calculations, revealing its microscopic disorder and stability.

Findings

LiNiO$_2$ exhibits a high-entropy charge-glass state.

Electronic structure calculations reveal nearly degenerate phases.

This state explains key experimental features of LiNiO$_2$.

Abstract

Understanding microscopic properties of LiNiO$_2$, a Li-ion battery cathode material with extraordinarily high reversible capacity, has remained a challenge for decades. Based on extensive electronic structure calculations, which reveal a large number of nearly degenerate phases involving local Jahn-Teller effect as well as bond and oxygen-based charge disproportionation, we propose that LiNiO$_2$ exists in a high-entropy charge-glass like state at and below ambient temperatures. Recognizing the glassy nature of LiNiO$_2$ does not only explain its key experimental features, but also opens a new path in designing entropy-stabilized battery cathodes with superb capacities.