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Extraordinarily Large Electrocaloric Strength of Metal-Free Perovskites.
Advanced Materials ( IF 27.4 ) Pub Date : 2019-12-27 , DOI: 10.1002/adma.201906224
Jian-Jun Wang 1 , Daniel Fortino 1 , Bo Wang 1 , Xinye Zhao 1 , Long-Qing Chen 1
Affiliation  

The availability of materials with high electrocaloric (EC) strengths is critical to enabling EC refrigeration in practical applications. Although large EC entropy changes, ΔSEC , and temperature changes, ΔTEC , have been achieved in traditional thin-film ceramics and polymer ferroelectrics, they require the application of very high electric fields and thus their EC strengths ΔSEC /ΔE and ΔTEC /ΔE are too low for practical applications. Here, a fundamental thermodynamic description is developed, and extraordinarily large EC strengths of a metal-free perovskite ferroelectric [MDABCO](NH4 )I3 (MDABCO) are predicted. The predicted EC strengths: isothermal ΔSEC /ΔE and adiabatic ΔTEC /ΔE for MDABCO are 18 J m kg-1 K-1 MV-1 and 8.06 K m MV-1 , respectively, more than three times the largest reported values in BaTiO3 single crystals. These predictions strongly suggest the metal-free ferroelectric family of materials as the best candidates among existing materials for EC applications. The present work not only presents a general approach to developing thermodynamic potential energy functions for ferroelectric materials but also suggests a family of candidate materials with potentially extremely high EC performance.

中文翻译:

无金属钙钛矿的超大电热强度。

具有高电热(EC)强度的材料的可用性对于在实际应用中实现EC制冷至关重要。尽管在传统的薄膜陶瓷和聚合物铁电材料中已经实现了较大的EC熵变化ΔSEC和温度变化ΔTEC,但它们需要施加非常高的电场,因此它们的EC强度ΔSEC/ΔE和ΔTEC/ΔE也是如此实际应用中低。在此,提出了基本的热力学描述,并预测了无金属钙钛矿铁电体[MDABCO](NH4)I3(MDABCO)的超大型EC强度。预测的EC强度:MDABCO的等温ΔSEC/ΔE和绝热ΔTEC/ΔE分别为18 J m kg-1 K-1 MV-1和8.06 K m MV-1,是BaTiO3单剂中最大报告值的三倍以上。晶体。这些预测强烈表明,无金属铁电材料家族是EC应用现有材料中的最佳候选材料。本工作不仅提出了开发铁电材料热力学势能函数的一般方法,而且提出了一系列具有潜在极高EC性能的候选材料。
更新日期:2020-02-18
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