High electrocaloric effect in barium titanate-sodium niobate ceramics with core-shell grain assembly

Journal of Materiomics

卷:6

Guangzu Zhang¹  Xiaoshi Qian²  Haibo Zhang³  Dong Su⁴  Shenglin Jiang⁴  Chao Zhang⁴  Wenru Li⁴  Meng Shen⁴  Quanpei Du⁴  Bing Li⁵ 

[1] Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518057, China;

[2] Institute of Refrigeration and Cryogenics, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China;

[3] School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China;

[4] School of Optical and Electronic Information, Engineering Research Center for Functional Ceramics MOE and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China;

[5] Shenyang National Laboratory (SYNL) for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China;

关键词: Electrocaloric effect;    Core-shell structure;    Lead-free ceramics;    Internal stress;    High temperature stability;   

DOI  :  

来源: DOAJ

【 摘 要 】

Electrocaloric effect (ECE) is promising in realizing solid-state cooling as an alternative to the conventional refrigeration with environmentally harmful coolant and low efficiency. High ECE in lead-free ferroelectric ceramics is highly desirable for the EC cooling. In this work, different from the researches that tune the ECE by conventional compositional design or external stress engineering, we fabricated the (1-x)BaTiO3-xNaNbO3 (BTO-xNN) lead-free ceramics with a core-shell grain structure arising from the inhomogeneous stoichiometry of element distribution, leading to the internal compressing stress in the grains. It is interesting that the phase transition behavior, including the phase transition temperature and the diffusion property, is regulated by the core-shell grain structure induced internal stress, which can be capitalized on for the favorable ECE. Cooperated with 0.02 NN, a high ECE, e.g. adiabatic temperature change (ΔT) of 3.6 K and isothermal entropy change (ΔS) of 4.5 J kg−1 K−1, is attained in the BTO ceramic. As the internal stress further increases with more NN, the BTO-0.06NN exhibits an extremely stable ECE with a variety rate below ±4% in a wide temperature range from 300 K to 360 K. This work provides a novel approach to explore pronounced ECE in lead-free ferroelectrics for eco-friendly refrigeration.

【 授权许可】

Unknown