High entropy oxides for reversible energy storage

TLDR

Entropy stabilization of multi‑cation oxide structures has spurred research into high‑entropy oxides with novel properties arising from cation interactions. This study investigates the reversible lithium‑storage performance of high‑entropy oxides, the mechanisms involved, and how entropy stabilization affects their electrochemical behavior. Entropy stabilization enhances capacity retention and cycling stability, while the electrochemical response can be tuned by selecting different metal cations.

Abstract

In recent years, the concept of entropy stabilization of crystal structures in oxide systems has led to an increased research activity in the field of "high entropy oxides". These compounds comprise the incorporation of multiple metal cations into single-phase crystal structures and interactions among the various metal cations leading to interesting novel and unexpected properties. Here, we report on the reversible lithium storage properties of the high entropy oxides, the underlying mechanisms governing these properties, and the influence of entropy stabilization on the electrochemical behavior. It is found that the stabilization effect of entropy brings significant benefits for the storage capacity retention of high entropy oxides and greatly improves the cycling stability. Additionally, it is observed that the electrochemical behavior of the high entropy oxides depends on each of the metal cations present, thus providing the opportunity to tailor the electrochemical properties by simply changing the elemental composition.