Spontaneous‐Chessboard‐Ordered Structure of PbMg <sub>0.5</sub> W <sub>0.5</sub> O <sub>3</sub> Multilayer Capacitors Offers Giant Electrocaloric Enthalpy Change Below Room Temperature
Ruowei Yin, Dong Liu, Xiaowei Lv, Kailun Jiao, Yuxuan Hou, Junjie Li, Huajie Luo, Rongju Zhong, Xiaoying Qi, Chuanbao Liu, Yanjing Su, Lijie Qiao, Renchao Che, Lifeng Zhu, Turab Lookman, Yang Bai
Abstract
Abstract For high‐efficiency and zero‐emission electrocaloric refrigeration, a continuing challenge is to achieve a large enthalpy change (Δ H ) below/near room temperature (RT) for commercial viability. To address this issue, antiferroelectric PbMg 0.5 W 0.5 O 3 multilayer ceramic capacitors (PMW MLCCs) are synthesized as a result of spontaneous‐chessboard‐ordered arrangement of heterovalent B‐site ions. PMW has a giant Δ H (3.92 J g −1 ) near RT (36 °C), and the stress‐engineered MLCCs further lower the Curie temperature to below RT (19 °C). The complete polarization under high electric fields enables a full release of the large Δ H and produces both a giant positive and negative electrocaloric effect, Δ T max+ = 7.17 K at 20 °C (@240 kV cm −1 ) and Δ T max‐ = −4.11 K at 10 °C (@180 kV cm −1 ). Moreover, the coefficient of performance (COP) is dramatically improved by an electric‐energy‐recovery circuit, and a colossal value of 350 is achieved in a prototypical cooler with 400 MLCCs. This outstanding refrigeration performance opens the door to PMW MLCCs for RT cooling applications with large market potential.