Phase-transition induced giant negative electrocaloric effect in a lead-free relaxor ferroelectric thin film. Issue 5 (2nd May 2019)

• Record Type: Journal Article
• Authors: Peng, Biaolin; Zhang, Qi; Gang, Bai; Leighton, Glenn J. T.; Shaw, Christopher; Milne, Steven J.; Zou, Bingsuo; Sun, Wenhong; Huang, Haitao; Wang, Zhonglin
• Is Part Of: Energy & environmental science. Volume 12:Issue 5(2019)
• Page Start: 1708
• Page End: 1717
• Publication Date: 2019-05-02
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/c9ee00269c
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : Ferroelectric/antiferroelectric thin/thick films with large positive or negative electrocaloric (EC) effects could be very useful in designing commercial refrigeration devices. Abstract : Ferroelectric/antiferroelectric thin/thick films with large positive or negative electrocaloric (EC) effects could be very useful in designing commercial refrigeration devices. Here, a giant negative EC effect (maximum Δ T ∼ −42.5 K with Δ S ∼ −29.3 J K −1 kg −1 ) comparable to the best positive EC effects reported so far is demonstrated for 0.5(Ba0.8 Ca0.2 )TiO3 –0.5Bi(Mg0.5 Ti0.5 )O3 (BCT–BMT) lead-free relaxor ferroelectric thin films prepared on Pt(111)/TiO x /SiO2 /Si substrates using a sol–gel method. An electric-field induced structural phase transition (nanoscale tetragonal and orthorhombic to rhombohedral) along the out-of-plane [111] direction plays a very key role in developing the giant negative EC effect. This breakthrough will pave the way for practical applications of next-generation refrigeration devices with high cooling efficiency in one cycle by ingeniously utilizing and combining both the giant negative and positive EC effects. Moreover, a large energy density of 51.7 J cm −3 with a high power density of 1.15 × 10 10 W kg −1 at room temperature is also achieved in the thin film, indicating that it is also an attractive multifunctional material for energy storage.