Giant negative ECE near room temperature and large positive ECE of CoFe2O4-BiFeO3/P(VDF-TrFE) sandwich flexible films

IF 6.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Applied Surface Science Pub Date : 2025-05-30 DOI:10.1016/j.apsusc.2025.163673

Xiang Lv , Lingfang Xu , Yalong Ge , Tian Liang , Ronghua Qin , Changping Yang

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Abstract

The electrocaloric effect (ECE) represents an eco-friendly, solid-state cooling technique utilizing a safe and potent electric field to facilitate the refrigeration process. This research demonstrates that incorporating CoFe₂O₄ (CFO) and BiFeO₃ (BFO) at a 1:1 mass ratio into P(VDF-TrFE) results in notable giant negative ECE at near room temperature and positive ECE in sandwiched composite films. With a 5 wt% addition of CFO and BFO, the composite films exhibited giant adiabatic temperature changes of 11.3 K at 374.4 K and −24 K at 316 K. Using the Landau model, we confirmed the occurrence of both positive and negative ECEs. We predicted an adiabatic temperature change as high as −37.2 K at an electric field of 120 MV m⁻¹. The exceptional performance of the flexible, sandwiched composite films is attributed to their optimized microstructure and the strengthened local field around the dipoles, a result of the conductive CoFe₂O₄ and BiFeO₃ nanoparticles. These dual-functional cooling films provide a means to boost the ECE in flexible materials, holding significant promise for applications in solid-state refrigeration tailored for flexible electronics. Future applications of the composite films may extend to various scenarios beyond the known multiferroic properties of BiFeO₃ and the magnetic characteristics of CoFe₂O₄.

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CoFe2O4-BiFeO3/P（VDF-TrFE）夹层柔性薄膜在室温下具有较大的负ECE和较大的正ECE

电热效应（ECE）代表了一种生态友好的固态冷却技术，利用安全和强大的电场来促进制冷过程。本研究表明，将CoFe2O4 （CFO）和BiFeO3 （BFO）以1:1的质量比掺入P（VDF-TrFE）中，在近室温下产生显著的负ECE，而在夹层复合膜中产生正ECE。当CFO和BFO的添加量为5 wt%时，复合膜的绝热温度变化很大，在374.4 K时为11.3 K，在316 K时为−24 K。利用朗道模型，我们证实了阳性和阴性ECEs的存在。我们预测在120 MV m−1的电场下，绝热温度变化高达- 37.2 K。由于CoFe2O4和BiFeO3纳米粒子的导电性，这种柔性夹层复合薄膜的优异性能归功于其优化的微观结构和偶极子周围增强的局部场。这些双功能冷却膜为提高柔性材料的ECE提供了一种手段，在为柔性电子产品量身定制的固态制冷应用中具有重要的前景。复合薄膜的未来应用可能会扩展到BiFeO3的已知多铁性和CoFe2O4的磁性之外的各种场景。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Surface Science 工程技术-材料科学：膜

CiteScore

12.50

自引率

7.50%

发文量

3393

审稿时长

67 days

期刊介绍： Applied Surface Science covers topics contributing to a better understanding of surfaces, interfaces, nanostructures and their applications. The journal is concerned with scientific research on the atomic and molecular level of material properties determined with specific surface analytical techniques and/or computational methods, as well as the processing of such structures.