2025-05-20 上海交通大学 (SJTU)
Fig. 1. Design and key properties of “high-polar-entropy” electrocaloric ceramics.
＜関連情報＞
高極性エントロピーペロブスカイト酸化物における巨大電気熱量効果 Giant electrocaloric effect in high-polar-entropy perovskite oxides
Feihong Du,Tiannan Yang,Hua Hao,Shangshu Li,Chenhang Xu,Tian Yao,Zhiwu Song,Jiahe Shen,Chenyun Bai,Ruhong Luo,Donglin Han,Qiang Li,Shanyu Zheng,Yingjing Zhang,Yezhan Lin,Zhenhua Ma,Haotian Chen,Chenyu Guo,Jiawang Feng,Shengyi Zhong,Ruilin Mai,Guodong Hou,Haixin Qiu,Meng Xie,… Xiaoshi Qian
Nature Published:09 April 2025
DOI:https://doi.org/10.1038/s41586-025-08768-8
Abstract
Materials with a high electrocaloric effect (ECE)1,2 tend to favour a disordered yet easily tunable polar structure. Perovskite ferroelectrics3 stand out as ideal candidates owing to their high dielectric responses and reasonable thermal conductivity. The introduction of multielement atomic distortions induces a high-polar-entropy state4 that notably increases the ECE by effectively overcoming the constraints imposed by highly ordered, polar-correlated perovskite structures. Here we developed a lead-free relaxor ferroelectric with strong polar disorder through targeted multielement substitution at both the A and B sites of the perovskite, effectively distorting the lattice structure and inducing a variety of nanoscale polar configurations, polymorphic polar variants and non-polar regions. A combination of these multielement-induced features led to an increased density of interfaces, significantly enhancing the polar entropy. Remarkably, a high ECE for an entropy change of about 15 J kg−1 K−1 under a 10 MV m−1 field is observed for the material across a broad temperature range exceeding 60 °C. The formation of ultrafine, dispersed, multiphase lattice configurations leads to high-polar-entropy ferroelectric oxides with a high ECE and a long lifetime of over 1 million cycles that are suitable for manufacturing multilayer ceramic capacitors for practical electrocaloric refrigeration applications.
