Electric Endurance Research Articles

Electrocaloric effect and energy-storage performance in grain-size-engineered PBLZT antiferroelectric thick films

The effects of grain size on dielectric properties, energy-storage performance and electrocaloric effect (ECE) of Pb0.85Ba0.05La0.10(Zr0.90Ti0.10)O3 (PBLZT) antiferroelectric thick films were systematically studied. As the grain size was increased, dielectric constant of the thick films was increased, while their critical breakdown field was decreased. A giant reversible adiabatic temperature change of ∆T = 19.9 °C at room temperature was achieved in the PBLZT AFE thick film with a grain size of 0.59 µm. However, a huge recoverable energy-storage density of 33.6 J/cm3 and a high efficiency of 73 % were observed in the film with the smallest grain size of 0.19 µm at its breakdown field, because of its excellent electric field endurance. In addition, all the samples had a low leakage current density of below 10−6 A/cm2 at room temperature. These results indicated that our PBLZT AFE thick films could be a promising candidate for applications in high energy-storage density capacitors and solid-cooling devices by properly controlling their grain size.

Technical Analysis and Research on the Endurance of Electric Vehicles

With the development and extension of electric vehicle in our country, research on electric vehicle technology becomes a hot topic in recent years. This paper starts with the technical barriers from electric vehicle endurance ability and described the improving methods of electric automobile thoroughly, pointed out the existing problems in the process of application about the methods in this paper. Then put forward the application of solar energy, wind energy technology in electric cars, proposed a research direction for the development of electric vehicle. At last, the paper proposed a research direction for the development of electric vehicle.

Fabrication and Properties of Microcapacitors with a One-nanometer-thick Single Ti0.87O2 Nanosheet

Abstract The dielectric and insulating properties of a single Ti0.87O2 nanosheet were investigated by fabricating an Au/single Ti0.87O2 nanosheet/Au planar microcapacitor structure. Capacitance and electric measurements of the nanosheet microcapacitor showed reproducibly good performance as a gate insulator: almost frequency-independent capacitance up to 1 MHz and extremely high electric field endurance of ≥ 20 MV cm−1.

Integrative Control of Regenerative Braking System and Anti-Lock Braking System

For Electric Vehicle (EV), energy saving and endurance mileage prolonging are very important. Regenerative Braking System (RBS) is a key point in this respect. At the same time, braking safety is a rigid demand of EV. In this respect, the Anti-lock Braking System (ABS) has an excellent performance. As a result, the integration of RBS and ABS plays an important role in the development of the EV control. In this paper, a dynamic adaptive threshold theory decides when RBS should exist will be studied, and when the states of vehicle reach the adaptive threshold, a sliding mode control method will be used to meet the total braking force and the system will reduce the motor braking force. Before slip rate of vehicle reaches the ABS threshold, the regenerative braking force will be reduced to 0. The braking safety will be improved in this way.

Voltage endurance characteristics of epoxy/silica nanocomposites

AbstractTwo kinds of epoxy/silica nanocomposites, specifically Aerosil and Nanopox specimens, were prepared to clarify the effect of nano‐filler dispersion and of coupling agents on electric field endurance. According to SEM observation, nano‐fillers were well dispersed in the former specimens, while some agglomeration was found in the latter specimens. This difference caused different characteristics for partial discharge resistance and treeing resistance. Partial discharge resistance was improved only by adding nano‐fillers, and treeing resistance was improved not only by adding nano‐fillers but also by uniformly dispersing the nano‐fillers. Coupling agents were also effective for treeing resistance in both kinds of specimens. It was then clarified that nano‐fillers and coupling agents could improve partial discharge and treeing resistance, but that treeing resistance could be upgraded or degraded depending on the level of nano‐filler dispersion. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(12): 65–73, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10338

Optimization Procedure for Improvement of Thermal Interruption Capability of Tandem-puffer Interrupting Chamber -90% SLF Interruption for the Rating of 63kA-50Hz-

63kA-50Hz 90% short line fault (L90) is severer than 50kA-60Hz L90 from the points of view of electric endurance and interruption window. Interruption criteria and an optimization method of the chamber design are discussed to improve thermal interruption capability with it. The combination of the SA (Simulated Annealing) and MMFD (Modified Method of Feasible Directions) is applied to the optimization procedure. The optimized chambers with superior electric reliability are designed at 63kA-50Hz to improve gas density at current zero in thermal volume. 63kA-50Hz L90 interruptions are performed with the new chamber. In addition, influence of gas blast angle of nozzle on L90 interruption is clarified.

Ferroelectric Transistors with Nanowire Channel: Toward Nonvolatile Memory Applications

We report the fabrication and characterization of ZnO nanowire memory devices using a ferroelectric Pb(Zr(0.3)Ti(0.7))O(3) (PZT) film as the gate dielectric and the charge storage medium. With a comparison to nanowire transistors based on SiO(2) gate oxide, the devices were evaluated in terms of their electric transport, retention, and endurance performance. Memory effects are observed as characterized by an eminent counterclockwise loop in I-V(g) curves, which is attributed to the switchable remnant polarization of PZT. The single-nanowire device exhibits a high (up to 10(3)) on/off ratio at zero gate voltage. Our results give a proof-of-principle demonstration of the memory application based on a combination of nanowires (as channels) and ferroelectric films (as gate oxide).

Voltage Endurance Characteristics of Epoxy/Silica Nanocomposites

Two kinds of epoxy/silica nanocomposites, i.e. Aerosil and Nanopox specimens, were prepared to clarify the effect of nano-filler dispersion and of coupling agents on electric field endurance. According to SEM observation, nano-fillers were well dispersed in the former specimens, while some agglomeration was found in the latter specimens. This difference caused different characteristics for PD resistance and treeing resistance. PD resistance was improved only by adding nano-fillers, and treeing resistance was improved not only by adding nano-fillers but must by making nano-fillers uniformly dispersed. Coupling agents were also effective in treeing resistance in both kinds of specimens. It was then clarified that nano-fillers and coupling agents could improve PD and treeing resistance, but that treeing resistance could be upgraded or degraded depending on the level of nano-filler dispersion.

Improvement of electric fatigue properties in PLZT ferroelectric ceramics due to SrBi 2Ta 2O 9 incorporation

The influences of SrBi 2Ta 2O 9 (SBT) on dielectric and ferroelectric properties of Pb 0.94La 0.04(Zr 0.70Ti 0.30)O 3 ceramics were investigated systematically. X-ray diffraction (XRD) patterns of PLZT–SBT composite showed that there was no chemical reaction between PLZT and SBT. SEM pictures on fracture section reflected a main transgranular fracture mode. An abnormal and interesting increase of dielectric constant was observed after SBT incorporation. Hysteresis loops of PLZT–SBT composites turned to slimmer shape with the increase of SBT content. No apparent decrease of switchable polarization strength was found in PLZT–SBT composites after repeated polarization switching. HRTEM picture of SBT grain in PLZT–SBT composite revealed a transformation from order to disorder near the tip of grain boundary as well as low angle of grain boundary, which could release concentrated internal stress and served as improvement mechanism of electric fatigue endurance in PLZT–SBT composites.

Improvement of electric fatigue properties in Pb 0.94La 0.04(Zr 0.70Ti 0.30)O 3 ferroelectric capacitors due to SrBi 2Nb 2O 9 incorporation

The influences of SrBi 2Nb 2O 9 (SBN) on dielectric and ferroelectric properties of (PLZT) ceramics were systematically investigated. X-ray diffraction patterns of PLZT/SBN composite showed that there was no chemical reaction between PLZT and SBN in all cases. SEM pictures on the fracture section revealed a transformation from the transgranular to the intergranular mode with the increase of SBN content in composites. An abnormal and interesting increase of dielectric constant was observed after the incorporation of SBN in PLZT bulks, which could not be explained via the mixing law of dielectrics. Although it turned to be a little shrinkage, hysteresis loops still kept well-formed shapes in PLZT/SBN composites. Compared with the serious degradation of switchable polarization in pure PLZT sample after repeated polarization switching, no apparent decrease of switchable polarization strength was found in PLZT/SBN composites. The improvement mechanism of electric fatigue endurance in PLZT ceramics after SBN incorporation was attributed to the facilitation of oxygen vacancies’ mobility in the bismuth oxide layer in SBN.