Jingjing Tian

Evaluation of discharge energy density of antiferroelectric ceramics for pulse capacitors

The energy in pulse capacitors need to discharge rapidly to obtain high peak power. However, the discharge energy density of antiferroelectric (AFE) dielectrics for pulse capacitors is traditionally evaluated by hysteresis loop (defined as quasi-static method). To verify whether the quasi-static method is suitable for pulse applications, AFE ceramics Pb0.94La0.04[(Zr0.70Sn0.30)0.86Ti0.14]O3 were prepared, and their discharge energy density was calculated by hysteresis loop and pulse current (defined as dynamic method), respectively. A significant difference was found between these two kinds of results. Under 36u2009kV/cm, the discharge energy density calculated by 1u2009Hz hysteresis loop was 0.35u2009J/cm3 while that by pulse discharge current was only 0.18 J/cm3. It was found that the discharge energy density declined with increasing test frequency (0.1 Hz–100 Hz) and decreased further via dynamic hysteresis loop in microseconds scale. This declination can be explained by the viscous force during the motion of the ...

Pb0.94La0.04[(Zr0.70Sn0.30)0.90Ti0.10]O3 antiferroelectric bulk ceramics for pulsed capacitors with high energy and power density

Pb0.94La0.04[(Zr0.70Sn0.30)0.90Ti0.10]O3 antiferroelectric (AFE) bulk ceramics with both excellent energy storage and release properties were fabricated via the solid-state reaction method. The ceramics exhibited a high releasable energy density of 1.39u2009J/cm3, high efficiency of 92%, and good temperature stability under 104 kV/cm. Fast discharge current was measured, and a large current density up to 820u2009A/cm2 was achieved. The nonlinear dielectric behavior resulted in the variation of the discharge period of AFE ceramics. The stored charge was released completely due to the low remanent polarization, and the actually released energy density was about 1.0u2009J/cm3 in 400u2009ns. A high peak power density of 6.4u2009×u2009109u2009W/kg without a load resistor and an average power density of 3.16 × 108u2009W/kg with a 204.7 Ω load resistor were achieved in the rapid discharge process. The excellent energy storage and release properties indicate that the obtained antiferroelectric bulk ceramics are very promising for submicrosecond...

Polarization of antiferroelectric ceramics for pulse capacitors under transient electric field

The polarization of (Pb0.94La0.04)[(Zr0.7Sn0.3)0.87Ti0.13]O3 antiferroelectric (AFE) ceramics under unipolar pulse electric field was studied, and the transient hysteresis loop was achieved. Compared to the traditional quasi-static results, the forward transition field increases and the backward transition field decreases. The forward and backward phase transitions can be deduced in microseconds scale. Under the transient field, the releasable energy density decreases significantly, while the stored energy density changes slightly. Consequently, the efficiency decreases and the declination of energy density under transient situation is verified by the charge-discharge experiment. The above results prove the necessity of the study of the transient behaviors in AFE and the limitation of quasi-static analysis.

Nonlinear dielectric and discharge properties of Pb0.94La0.04[(Zr0.56Sn0.44)0.84Ti0.16]O3 antiferroelectric ceramics

Pb0.94La0.04[(Zr0.56Sn0.44)0.84Ti0.16]O3 antiferroelectric (AFE) ceramics were prepared by solid-state reaction and their nonlinear dielectric and discharge properties were studied. The releasable energy density and dielectric constant will increase sharply near 30u2009kV/cm due to the phase transition from antiferroelectric (AFE) to ferroelectric. The releasable energy density reaches maximum (0.50u2009J/cm3 under 40u2009kV/cm) at 30u2009°C and then decreases with temperature rise. The declination rate is less than 13% below 60u2009°C and will be remarkable at 160u2009°C due to the phase transition from AFE to paraelectric. The unique dielectric properties of AFE materials would result in special discharge properties. The discharge current density could be as high as 447u2009A/cm2, and the process finishes in sub-microsecond. The discharge current and hysteresis loop change very slightly after 10u2009000 charge–discharge cycles. The high energy density, fast discharge speed, and good fatigue resistance show the potential of obtained AF...

Effect of temperature-driven phase transition on energy-storage and -release properties of Pb0.97La0.02[Zr0.55Sn0.30Ti0.15]O3 ceramics

Temperature-driven phase transition of Pb0.97La0.02[Zr0.55Sn0.30Ti0.15]O3 ceramics was studied, and the consecutive ferroelectric-antiferroelectric-paraelectric (FE-AFE-PE) switching was confirmed. The materials have better dielectric tunability (−82% to 50%) in the AFE state than in the FE state. Also, the phase transition influences the energy-storage and -release performance significantly. A sharp increase in releasable energy density and efficiency was observed due to the temperature-driven FE-AFE transition. Highest releasable energy density, current density, and peak power density were achieved at 130u2009°C, which was attributed to the highest backward transition field. The stored charge was released completely in AFE and PE states in the microseconds scale, while only a small part of it was released in the FE state. The above results indicate the huge impact of temperature-driven phase transition on dielectrics performance, which is significant when developing AFE materials working in a wide temperat...

Effects of Ti content on dielectric and energy storage properties of (Pb0.94La0.04)[(Zr0.70Sn0.30)1−xTix]O3 ferroelectric/antiferroelectric ceramics

Ferroelectric/antiferroelectric (FE/AFE) ceramics with composition of (Pb0.94La0.04)[(Zr0.70Sn0.30)1−xTix]O3 were fabricated via solid state reaction and the effects of Ti content on dielectric and energy storage properties were studied. High releasable energy density of 1.03J/cm3 was obtained when x=0.12 under 65.7kV/cm. With increasing Ti content, both the forward and backward phase transition fields would decrease. When x=0.16, the dielectrics would be under FE state at room temperature (22∘C) and the phase transition from FE to AFE and then to paraelectric (PE) was observed with temperature rise. The discharge properties were also studied and the results proved that the stored charge in AFE could be released much more completely than that in FE.