title: Colossal Room-Temperature Electrocaloric Effect in Ferroelectric Polymer Nanocomposites Using Nanostructured Barium Strontium Titanates.
abstract: The electrocaloric effect (ECE) refers to conversion of thermal to electrical energy of polarizable materials and could form the basis for the next-generation refrigeration and power technologies that are highly efficient and environmentally friendly. Ferroelectric materials such as ceramic and polymer films exhibit large ECEs, but each of these monolithic materials has its own limitations for practical cooling applications. In this work, nanosized barium strontium titanates with systematically varied morphologies have been prepared to form polymer nanocomposites with the ferroelectric polymer matrix. The solution-processed polymer nanocomposites exhibit an extraordinary room-temperature ECE via the synergistic combination of the high breakdown strength of a ferroelectric polymer matrix and the large change of polarization with temperature of ceramic nanofillers. It is found that a sizable ECE can be generated under both modest and high electric fields, and further enhanced greatly by tailoring the morphology of the ferroelectric nanofillers such as increasing the aspect ratio of the nanoinclusions. The effect of the geometry of the nanofillers on the dielectric permittivity, polarization, breakdown strength, ECE and crystallinity of the ferroelectric polymer has been systematically investigated. Simulations based on the phase-field model have been carried out to substantiate the experimental results. With the remarkable cooling energy density and refrigerant capacity, the polymer nanocomposites are promising for solid-state cooling applications.
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.|‡School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
authors.forename: Guangzu
authors.initials: G
authors.lastname: Zhang
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.|§College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Tiannan
authors.initials: T
authors.lastname: Yang
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Long-Qing
authors.initials: LQ
authors.lastname: Chen
authors.affiliation: ‡School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
authors.forename: Shenglin
authors.initials: S
authors.lastname: Jiang
authors.affiliation: †Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
keywords: electrocaloric effect; ferroelectrics; nanostructures; polymer nanocomposites