Wu Bo, Tao Hong, Chen Kui, Xing Zhipeng, Wu Yan-Qi, Thong Hao-Cheng, Zhao Lin, Zhao Chunlin, Xu Ze, Liu Yi-Xuan, Yao Fang-Zhou, Zhou Tianhang, Ma Jian, Wei Yan, Wang Ke, Zhang Shujun
Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station & Sichuan Province Key Laboratory of Information Materials, Southwest Minzu University, Chengdu, China.
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China.
Nat Commun. 2025 Aug 13;16(1):7515. doi: 10.1038/s41467-025-61860-5.
The electrocaloric effect of ferroelectrics holds great promise for solid-state cooling, potentially replacing traditional vapor-compression refrigeration systems. However, achieving adequate electrocaloric cooling capacity at room temperature remains a formidable challenge due to the need for a high intrinsic electrocaloric effect. While barium titanate ceramic exhibits a pronounced electrocaloric effect near its Curie temperature, typical chemical modifications to enhance electrocaloric properties at room temperature often reduce this intrinsic electrocaloric effect. Herein, a structural design is introduced for barium titanate-based ceramics by incorporating isovalent cations. This leads to a well-ordered local structure that decreases the Curie temperature to room temperature while preserving a sharp phase transition, enabling a large dielectric constant and tunable polarization. This design achieves a remarkable electrocaloric strength of ~1.0 K·mm/kV, surpassing previous reports. Atomic-resolution structural analyses reveal that the presence of multiscale nanodomains (from ~10 nm to >100 nm), and the dipole polarization distribution with gradual dipole rotation enable rapid phase transition and facile polarization rotation, accounting for the giant electrocaloric response. This work provides a strategy for achieving a strong intrinsic electrocaloric effect in ferroelectrics near room temperature and offers key insights into the microstructure landscapes driving this enhanced electrocaloric effect.
铁电体的电热效应在固态冷却方面极具潜力，有望取代传统的蒸汽压缩制冷系统。然而，由于需要高本征电热效应，在室温下实现足够的电热冷却能力仍然是一项艰巨的挑战。虽然钛酸钡陶瓷在其居里温度附近表现出显著的电热效应，但为了在室温下提高电热性能而进行的典型化学改性往往会降低这种本征电热效应。在此，通过引入等价阳离子，为钛酸钡基陶瓷引入了一种结构设计。这导致了一种有序的局部结构，将居里温度降低到室温，同时保持尖锐的相变，从而实现大介电常数和可调极化。这种设计实现了约1.0 K·mm/kV的显著电热强度，超过了先前的报道。原子分辨率结构分析表明，多尺度纳米域（从约10 nm到>100 nm）的存在以及偶极子极化分布与逐渐的偶极子旋转，使得能够实现快速相变和容易的极化旋转，这解释了巨大的电热响应。这项工作为在室温附近的铁电体中实现强本征电热效应提供了一种策略，并为驱动这种增强电热效应的微观结构特征提供了关键见解。
