Achieving High Energy Density in PVDF-Based Polymer Blends: Suppression of Early Polarization Saturation and Enhancement of Breakdown Strength.
Polymers with high dielectric strength and favorable flexibility have been considered promising materials for dielectrics and energy storage applications, while the achievable energy density (Ue) of polymer is rather limited by the intrinsic low dielectric constant and ferroelectric hysteresis. Polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene (P(VDF-TrFE-CFE)) with ultrahigh εrof >50 is considered promising in achieving high Ueof polymer dielectrics. However, P(VDF-TrFE-CFE) only exhibits moderate Uedue to the early saturation of electrical polarization at low electric field. In this contribution, we show that, by blending P(VDF-TrFE-CFE) with polyvinylidene fluoride (PVDF), the early saturation of P(VDF-TrFE-CFE) is substantially suppressed, giving rise to concomitant enhancement of dielectric permittivity and breakdown strength. An ultrahigh energy density of 19.6 J/cm3is thus achieved at ∼640 kV/mm, which is 1600% greater than Ueof the benchmark biaxially oriented polypropylene (BOPP, 1.2 J/cm3at 640 kV/mm). Results of phase field simulations reveal that the interfaces between PVDF and P(VDF-TrFE-CFE) play a critical role by not only suppressing early saturation of electrical polarization in P(VDF-TrFE-CFE) but also inducing additional interfacial polarization. Binary phase diagram of P(VDF-TrFE-CFE)/PVDF blends is also systematically explored with their dielectric and energy storage behavior studied.
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Xin
X
Zhang
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Yang
Y
Shen
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Zhonghui
Z
Shen
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Jianyong
J
Jiang
Department of Materials Science and Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Longqing
L
Chen
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University , Beijing 100084, China.
Ce-Wen
CW
Nan
dielectric; electric displacement; energy density; ferroelectricity; polymer blends