title: Dielectric Elastomer Generator with Improved Energy Density and Conversion Efficiency Based on Polyurethane Composites.
abstract: Dielectric elastomer generators (DEGs), which follow the physics of variable capacitors and harvest electric energy from mechanical work, have attracted intensive attention over the past decade. The lack of ideal dielectric elastomers, after nearly two decades of research, has become the bottleneck for DEGs' practical applications. Here, we fabricated a series of polyurethane-based ternary composites and estimated their potential as DEGs to harvest electric energy for the first time. Thermoplastic polyurethane (PU) with high relative permittivity (∼8) was chosen as the elastic matrix. Barium titanate (BT) nanoparticles and dibutyl phthalate (DBP) plasticizers, which were selected to improve the permittivity and mechanical properties, respectively, were blended into the PU matrix. As compared to pristine PU, the resultant ternary composite films fabricated through a solution casting approach showed enhanced permittivity, remarkably reduced elastic modulus, and relatively good electrical breakdown strength, dielectric loss, and strain at break. Most importantly, the harvested energy density of PU was significantly enhanced when blended with BT and DBP. A composite film containing 25 phr of BT and 60 phr of DBP with the harvested energy density of 1.71 mJ/cm3was achieved, which is about 4 times greater than that of pure PU and 8 times greater than that of VHB adhesives. Remarkably improved conversion efficiency of mechano-electric energy was also obtained via cofilling BT and DBP into PU. The results shown in this work strongly suggest compositing is a very promising way to provide better dielectric elastomer candidates for forthcoming practical DEGs.
authors.affiliation: Department of Polymer Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China.
authors.forename: Guoling
authors.initials: G
authors.lastname: Yin
authors.affiliation: Department of Polymer Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Polymer Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China.
authors.forename: Feilong
authors.initials: F
authors.lastname: Song
authors.affiliation: Department of Polymer Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China.
authors.forename: Christophe
authors.initials: C
authors.lastname: Renard
authors.affiliation: Department of Electrical Engineering, Tsinghua University , Beijing 100084, People's Republic of China.
authors.forename: Zhi-Min
authors.identifier: http://orcid.org/0000-0003-4427-8779
authors.initials: ZM
authors.lastname: Dang
authors.affiliation: Elements Department, Beijing Institute of Fashion Technology , Beijing 100029, People's Republic of China.
authors.forename: Chang-Yong
authors.initials: CY
authors.lastname: Shi
authors.affiliation: Department of Polymer Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing , Beijing 100083, People's Republic of China.
authors.forename: Dongrui
authors.identifier: http://orcid.org/0000-0002-0306-9439
authors.initials: D
authors.lastname: Wang
keywords: composite; dielectric elastomer generator; energy conversion; energy density; polyurethane