Zhenkun Xie

Large enhancement of the recoverable energy storage density and piezoelectric response in relaxor-ferroelectric capacitors by utilizing the seeding layers engineering

In this work, we demonstrate an approach to improve the recoverable energy-storage performance and piezoelectric response of 0.4Bi(Ni1/2Zr1/2)O3-0.6PbTiO3 (BNZ-PT) relaxor-ferroelectric film capacitors by utilizing the seeding layers engineering. Highly (100)-oriented BNZ-PT films were prepared through alternatively introducing PbO seeding layers, and the effects of PbO seeds on microstructure and electrical properties were investigated in details. Compared to the films without seeds, the PbO-seeded BNZ-PT films exhibit significant enhancement in dielectric and piezoelectric properties as well as energy-storage performance. The maximum energy-storage density of 56.1±2.4 J/cm3 and a piezoelectric coefficient as high as 125±10 pm/V have been achieved in the highly (100)-oriented BNZ-PT films at 2167 kV/cm, which are increased by 40.6% and 50.6% compared to the films without seeds, respectively. The observed tremendous enhancement of energy-storage performance and piezoelectric response can be attributed to ...

Bi(Ni1/2Zr1/2)O3-PbTiO3 relaxor-ferroelectric films for piezoelectric energy harvesting and electrostatic storage

In this Letter, we demonstrated that both a high energy-storage density and a large piezoelectric response can be attained simultaneously in relaxor-ferroelectric 0.4Bi(Ni1/2Zr1/2)O3-0.6PbTiO3 films prepared by chemical solution deposition. The as-prepared films had a pure-phase perovskite structure with an excellent crystalline morphology, featuring a moderate relative permittivity ( er  ∼ 800–1100), a low dissipation factor ( tan δ  < 5%) and strong relaxor-like behavior ( γ  = 1.81). An ultra-high energy-storage density of 39.8 J/cm3 at 2167 kV/cm was achieved at room temperature. Moreover, the 0.4Bi(Ni1/2Zr1/2)O3-0.6PbTiO3 films exhibited a considerably large effective piezoelectric coefficient of 83.1 pm/V under substrate clamping, which is comparable to the values obtained for lead zirconate titanate films. Good thermal stabilities in both the energy-storage performance and the piezoelectric properties were obtained over a wide range of temperatures, which makes 0.4Bi(Ni1/2Zr1/2)O3-0.6PbTiO3 films a...

Improvement of the recoverable energy storage density and efficiency by utilizing the linear dielectric response in ferroelectric capacitors

The recoverable energy storage performance of 400 nm undoped and 4 mol. % Nb-doped PbZr0.4Ti0.6O3 ferroelectric capacitors was studied. The DC dielectric strength improved from 1351 kV/cm (undoped) to 1878 kV/cm (Nb-doped), and the latter capacitors had high recoverable energy storage density up to 20 J/cm3 with efficiency of 70%, benefiting mainly from the linear dielectric response. This study suggests that donor doping is an effective way to improve the dielectric strength and illustrates the significant role of the linear dielectric response in ferroelectrics for high power applications.

Effect of PbO excess on the microstructure, dielectric and piezoelectric properties, and energy-storage performance of Bi(Ni1/2Ti1/2)O3–PbTiO3 thin films

Ferroelectric Bi(Ni1/2Ti1/2)O3?PbTiO3 (BNT?PT) thin films near the morphotropic phase boundary (MPB) with different amount of excess lead (0, 10, and 20%) were successfully deposited onto Pt(111)/Ti/SiO2/Si substrates via a chemical solution approach. The effects of excess lead on the microstructure, dielectric and piezoelectric properties, and energy-storage performance of the thin films were investigated in detail. X-ray diffraction results revealed that the films showed an increasing (100)-orientation with an increasing amount of excess lead. Dielectric, ferroelectric, and current?voltage measurements showed that the films with more excess lead exhibited an enhanced dielectric constant and greater back-switch behavior, while the smaller leakage current density. As a result, the energy-storage density was also markedly improved from 22.8 to 50.2 J/cm3 under an electric field of 2250 kV/cm. The effective piezoelectric constant d33 increased from 41.5 to 70.1 pm/V with increasing excess lead from 0 to 20%.

Temperature-dependent polarization back-switching and dielectric nonlinearity in PbZr0.4Ti0.6O3 ferroelectric thin films

Temperature-dependent domains back-switching behavior and nonlinear dielectric response were studied in 200 nm fresh and aged PbZr0.4Ti0.6O3 thin films to compare domain walls motion under large and small signals. Expected thermally activation of domains back-switching and dielectric nonlinearity were observed at low temperature, however, abnormal thermally inhibited behavior occurred at higher temperatures. Such phenomenon was found in both fresh and aged films and the ageing process magnified such thermally inhibited effect. Analyzing nonlinear dielectric response with Rayleigh law suggested that the interaction between domain walls and pinning centers was strengthened at high temperature especially after ageing. Promoted pinning effect by rising temperature could reduce dielectric loss and this is practical for high temperature applications of ferroelectrics.