High-entropy perovskite oxides for energy materials: A review

High-entropy perovskite oxides (HEPOs) have recently attracted considerable attention due to their unique structure and properties. HEPOs are designed by incorporating multiple principal elements into a single site in perovskite structures. This article provides a review of recent achievements in the application of HEPOs in energy materials. It first presents the development and progress of compositional design strategies for HEPOs. Subsequently, it reviews various structural descriptors for evaluating stability in HEPOs and summarizes synthesis methods of HEPOs with different dimensions. Additionally, it highlights the advantages of HEPOs in various energy-related applications such as dielectric energy storage, piezoelectric materials, solid oxide fuel cells, lithium-ion batteries, thermoelectric materials, catalysts, and supercapacitors. Furthermore, three remaining issues are identified, including the need for a strategy to design compositions based on target performance, the consideration of the influence of geometric and thermodynamic factors on phase formation, and the lack of understanding of the relationship between entropy and performance in HEPOs. The article proposes that future research should focus on function-oriented compositional design strategies that consider the precise relationship between configurational entropy and performance, complemented by accurate structure prediction.