High-entropy oxides: an emerging anode material for lithium-ion batteries.

High entropy oxides (HEOs) have gained significant attention in multiple research fields, particularly in reversible energy storage. HEOs with rock-salt and spinel structures have shown excellent reversible capacity and longer cycle spans compared to traditional conversion-type anodes. However, research on HEOs and their electrochemical performance remains at an early stage. In this highlight, we review recent progress on HEO materials in the field of lithium-ion batteries (LIBs). Firstly, we introduce the synthesis methods of HEOs and some factors that affect the morphology and electrochemical properties of the synthesized materials. We then elaborate on the structural evolution of HEOs with rock-salt and spinel structures in lithium energy storage and summarize the relationship between morphology, pseudocapacitance effect, oxygen vacancy, and electrochemical performance. In the end, we give the challenges of HEO anodes for LIBs and present our opinions on how to guide the further development of HEOs for advanced anodes.