The critical role of phase transition and composition regulation in inorganic perovskite electrocaloric materials

The electrocaloric effect (ECE) has arisen as a promising solid-state cooling technique. Inorganic perovskites as an innovative EC material have been widely investigated, due to their high energy efficiency, zero emissions, low cost, and ease of manipulation. However, it remains a challenge to achieve a giant ECE across a broad temperature range. Currently, the solution mainly focuses on the configurational entropy change from phase transition. To clarify the relationship between phase transitions and ECEs, this review discusses the EC features among different types of phase transitions, as well as the role of compositional regulation. Reasonable compositional regulation can combine the high configurational entropy in first-order phase transitions with the advantage of a wide phase transition temperature range in diffuse phase transitions, thereby addressing this challenge. The use of machine learning to discover new materials and improve material quality will be a key direction for future research.