The formation of stripe domains as a result of domain merging during local switching by a conductive SPM tip on Y cut of lithium niobate doped by MgO was studied. The stripe domains with proper ...length can be created by application of a positive voltage pulse after a negative one in the point displaced on a certain distance in Z + direction. The length of the stripe domain is exactly limited by the distance between the points of voltage application. The creation of periodical structures of the stripe domains with 1 μm period and 0.5 duty cycle was demonstrated.
The development of ABO3 perovskite-structured dielectric materials with high recoverable energy storage density (Wrec) and power density (PD) is crucial for the downsizing of pulsed power devices. ...Despite several research efforts, achieving a high Wrec over a wide working temperature range in an environmentally benign system remains a difficulty. A synergistic design strategy is given here, which includes concurrently doping at the A- and B-site to achieve a spread and depressed dielectric response, adding sintering aids, and employing advanced viscous polymer rolling technology for dense and ultra-thin ceramic samples, respectively. Finally, at a relatively low electric field of 380 kV/cm, an ultrahigh Wrec of 6.57 J/cm3 is realized in (Bi0.5Na0.5)0.93Ca0.07Ti0.85Zr0.15O3-0.5 wt% Li2CO3 component, which benefits from gentle polarization saturating and improved breakdown strength. The Wrec can be maintained above 6 J/cm3 while maintaining strong thermal stability (variation ≤ ± 3%) over a temperature range of 30–150 °C. Because BNT-based materials have such high energy storage performance and temperature stability, they are not only a promising candidate for replacing lead-based dielectrics, but also a valuable guide for developing new high-performance ferroelectric materials for future energy storage devices in the pulsed power system.
•Multiple engineering processes are proposed to enhance the energy storage performance.•An ultrahigh Wrec of 6.57 J/cm3 is achieved under a relatively low electric field.•A Wrec above 6 J/cm3 can be sustained in the temperature range of 30 °C~150 °C.
Growth of the wedge-like domains with charged domain walls was studied under local switching by a biased tip on nonpolar cut of MgO doped lithium niobate crystal. The tilt of the domain wall from the ...polar direction was controlled by voltage and number of switching pulses. The tilt reduction with voltage was observed. The essential tilt increasing up to 4° caused by width growth was revealed for application of the several pulses with the same parameters. The obtained results were attributed to the step generation in the external field and kink motion in the field produced by the charged kinks.
Despite the fact that relaxor ferroelectrics (RFEs) have been extensively researched because of their various advantages, there are still barriers to simultaneously increasing their energy storage ...density (Wrec) and efficiency (η). By substituting Bi(Mg0.5Sn0.5)O3 (BMS) and optimizing the formation process, this study follows a stepwise optimization route to achieve comprehensive exceptional energy storage performance (ESP) in Na0.5Bi0.5TiO3-Sr0.85Bi0.1TiO3 (NBT-SBT)-based ceramics. On the premise of constructing a Sr2+–Sr2+ ion pair at the A-site to ensure a large polarization, the introduction of Mg2+ and Sn4+ ions at the B-site further induces a local disordered field and promotes polar nanoregions. Following that, the viscous polymer process (VPP) used to synthesize NBT-SBT-BMS ceramics can thin the thickness, reduce defects, and boost compactness, hence improving the polarization difference (ΔP) and breakdown strength (Eb). Using the stepwise optimization route, we were able to attain a high ΔP of 64.6 μC cm−2 and an Eb of 440 kV cm−1 in 0.92(0.65NBT-0.35SBT)-0.08BMS-VPP ceramics. More crucially, an ultrahigh Wrec of 7.5 J cm−3 and a high η of 85% are simultaneously achieved, together with excellent temperature adaptability between 20 and 120 °C. Our superb ESP exceeds the majority of previously reported NBT-based ceramics, confirming the applicability of this stepwise optimization route to other similar high-performance dielectric ceramic designs.
Decay of isolated wedge-like domains with charged domain walls during local switching by a biased SPM tip on non-polar cut of lithium niobate doped by MgO was studied using piezoresponse force ...microscopy. It was found that domain imaging led to domains length reduction, whereas domain width did not change. Domain decay without scanning was also revealed. All the obtained effects were attributed to influence of injected charges, residual depolarization field, and AC voltage. Spatial distribution of electric field near SPM tip was simulated numerically. The obtained results provide new understanding of domain decay problem for nanodomain engineering.
Single phase barium titanate–bismuth ferrite ((1-x)BaTiO3-(x)BiFeO3, BTO-BFO) solid solutions were prepared using citric acid and ethylene glycol assisted sol-gel synthesis method. Depending on the ...dopant content the samples are characterized by tetragonal, tetragonal-pseudocubic, pseudocubic and rhombohedral structure as confirmed by Raman spectroscopy and XRD measurements. An increase of the BFO content leads to a reduction in the cell parameters accompanied by a decrease in polar distortion of the unit cell wherein an average particle size increases from 60 up to 350 nm. Non zero piezoresponse was observed in the compounds with pseudocubic structure while no polar distortion was detected in their crystal structure using X-ray diffraction method. The origin of the observed non-negligible piezoresponse was discussed assuming a coexistence of nanoscale polar and non-polar phases attributed to the solid solutions with high BFO content. A coexistence of the nanoscale regions having polar and non-polar character is considered as a key factor to increase macroscopic piezoresponse in the related compounds due to increased mobility of the domain walls and phase boundaries.
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•BaTiO3 undergoes transitions from trigonal to (pseudo)cubic and finally to trigonal.•Addition of BiFeO3 leads to larger grain size and more distinct size.•Domains correspond to grain size and domains become large in the solid solution.•Compositions nominally being centrosymmetric exhibit ferroelectricity.
We studied the domain structure self-organization at non-polar cuts of congruent lithium niobate under the action of biased moving scanning probe microscopy (SPM) tip. Analysis of the obtained domain ...structures revealed several types of switching: doubling, quadrupling, and chaotic. The period of created domains was shown to be similar in different non-polar cuts. The obtained results give further insight into domain interaction and domain structure self-organization.
•Two-step strategy provides a common way for designing high comprehensive ESP ceramic.•BST-BZN9VPP ceramic achieved an ultrahigh Wrec of 5.16 J/cm3 under 540 kV/cm.•The essential mechanism of high ...energy storage characteristics is visualized.
Dielectric capacitors are widely used because of their advanced performance, including superior power density and high charge–discharge speed. Nevertheless, limitations in energy-storage density (Wrec), efficiency (η) and thermal stability hinder their practical application. Herein, these concerns are addressed using a synergistic two-step strategy of designing the composition of Bi(Zn2/3Nb1/3)O3 and optimizing the preparation for viscous polymer processing (VPP), thus achieving domain engineering, enhanced relaxor behavior, and improved breakdown strength (Eb) in (Ba0.8Sr0.2)TiO3-based ceramics. The broadening of the permittivity peak and highly dynamic polar nanoregions (PNRs) are correlated to expected relaxation characteristics, as indicated by the brightness of atomic position and calculated spontaneous polarization vectors determined through transmission electron microscopy. The relatively small grain size and increased band gap, verified through scanning electron microscopy and ultraviolet − visible spectrophotometry, contribute to the Eb. A prominent Wrec of 5.16 J/cm3 under 540 kV/cm and excellent temperature stability (Wrec = 3.6 J/cm3, η = 92.8%, 20–120 °C) are achieved in 0.91(Ba0.8Sr0.2)TiO3 − 0.09Bi(Zn2/3Nb1/3)O3 ceramics formed by VPP (BZN9VPP). The material possesses an exceptional current density of 647.56 A/cm2, a power density of 113.32 MW/cm3, and a rapid discharge speed of < 60 ns. The comprehensive outstanding performance supports the great potential of this sample for application in pulsed power capacitors.
Electrochemical strain microscopy (ESM) can provide useful information on the ionic processes in materials at the local scale. This is especially important for ever growing applications of ...Li-batteries whose performance is limited by the intrinsic and extrinsic degradation. However, the ESM method used so far has been only qualitative due to multiple contributions to the apparent ESM signal. In this work, we provide a viable approach for the local probing of ionic concentration and diffusion coefficients based on the frequency dependence of the ESM signal. A theoretical basis considering the dynamic behavior of ion migration and relaxation and change of ion concentration profiles under the action of the electric field of the ESM tip is developed. We argue that several parasitic contributions to the ESM signal discussed in the literature can be thus eliminated. The analysis of ESM images using the proposed approach allows a quantitative mapping of the ionic diffusion coefficients and concentration in ionic conductors. The results are validated on Li-battery cathodes (LiMn
O
) extracted from commercial Li-batteries and can provide novel possibilities for their development and further insight into the mechanisms of their degradation.
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