High Piezoelectricity Research Articles

Achieving Stable Lithium Anodes through Leveraging Inevitable Stress Variations via Adaptive Piezoelectric Effect.

Unleashing the potential of lithium-metal anodes in practical applications is hindered by the inherent stress-related challenges arising from their limitless volume expansion, leading to mechanical failures such as electrode cracking, solid electrolyte interphase damage, and dendritic growth.Despite the various protective strategies to "combat" stress in lithium-metal anodes, they fail to address the intrinsic issue fundamentally. Here, a unique strategy is proposed that leverages the stress generated during the battery cycling via the piezoelectric effect, transforming to the adaptive built-in electric field to accelerate lithium-ion migration, homogenize the lithium deposition, and alleviate the stress concentration. The mechanism of the piezoelectric effect in modulating electro-chemomechanical field evolution is further validated and decoupled through finite element method simulations. Inspired by this strategy, a high sensitivity, fast responsive, and strength adaptability polymer piezoelectric is used to demonstrate the feasibility and the corresponding protected lithium-metal anode shows cycling stability over 6000h under a current density of 10mA cm-2 and extending life in a variety of coin and pouch cell systems. This work effectively tackles the stress-related issues and decoupling the electro-chemomechanical field evolution also contributes to developing more stable lithium anodes for future research.

Simultaneously achieved high piezoelectricity and resistivity in CaBi2Nb2O9-based ceramics with high curie temperature

To guarantee the functional operation of high-temperature piezoceramics in harsh circumstances, both large piezoelectricity and superior resistivity are prerequisites. However, it remains a formidable challenge to achieve these objects. Herein, we report Ce-doped CaBi2Nb2O9-based high-temperature polycrystals, which can simultaneously deliver a high piezoelectric coefficient d33 of 21.8 pC/N and decent resistivity ρ of 7.1 × 107 Ω﹒cm at 500 °C, along with a high Curie temperature of 916 °C. More encouragingly, the materials are also gifted with exceptional thermal stability ( < 10% variation of d33 in a broad range from ambient temperature up to 900 °C). In-depth multiscale structural characterizations unveil that the outstanding comprehensive performance of Ce-doped CaBi2Nb2O9-based ceramics originate from the synergistic effects of refined grain size and domain morphology, and reduced defect concentration. This work not only demonstrates that CaBi2Nb2O9-based ceramics hold enormous potential for high-temperature implements, but also offers prospects to exploit high-performance high-temperature piezoceramics.

The coexistence of high piezoelectricity and superior optical absorption in Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) monolayers.

Bismuth chalcogenide and its derivatives have been attracting attention in various fields as semiconductors or topological insulators. Inspired by the high piezoelectric properties of Janus Bi2TeSeS monolayer and the excellent optical absorption properties of the Bi2X3 (X = Te, Se, S) monolayers, we theoretically predicted four new-type two-dimensional (2D) monolayers Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) using the first principles combined with density functional theory (DFT). The thermal, dynamic, and mechanical stabilities of Janus Bi2X2Y monolayers were confirmed based on ab initio molecular dynamics (AIMD) simulations, phonon dispersion, and elastic constants calculations. Their elastic properties, band structures, piezoelectric, and optical properties were systematically investigated. It was found that Janus Bi2X2Y monolayers have a typical Mexican hat-shaped valence band edge structure and, therefore, have a ring-shaped flat band edge, which results in their indirect band gaps. The results show that Janus Bi2X2Y monolayers are semiconductors with moderate band gaps (0.62-0.98 eV at the HSE + SOC level). After considering the electron-phonon renormalization (EPR), the band gaps are reduced by less than 5% at 0 K under the zero-point renormalization (ZPR) and further reduced by approximately 10% at 300 K. Besides, Janus Bi2X2Y monolayers also exhibit excellent optical absorption properties in the blue-UV light region, with the peak values at the order of 8 × 105 cm-1. Particularly, the Janus Bi2Te2S monolayer was found to exhibit a piezoelectric strain coefficient d11 of up to 20.30 pm V-1, which is higher than that of most of the 2D materials. Our results indicate that Janus Bi2X2Y monolayers could be promising candidates in solar cells, optical absorption, and optoelectronic devices; especially, a Janus Bi2Te2S monolayer can also be an excellent piezoelectric material with great prospects in the fields of mechanical and electrical energy conversion.

Giant piezoresponse in nanoporous (Ba,Ca)(Ti,Zr)O3 thin film.

Lattice strain effects on the piezoelectric properties of crystalline ferroelectrics have been extensively studied for decades; however, the strain dependence of the piezoelectric properties at nano-level has yet to be investigated. Herein, a new overview of the super-strain of nanoporous polycrystalline ferroelectrics is reported for the first time using a nanoengineered barium calcium zirconium titanate composition (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCZT). Atomic-level investigations show that the controlled pore wall thickness contributes to highly strained lattice structures that also retain the crystal size at the optimal value (<30 nm), which is the primary contributor to high piezoelectricity. The strain field derived from geometric phase analysis at the atomic level and aberration-corrected high-resolution scanning transmission electron microscopy (STEM) yields of over 30% clearly show theoretical agreement with high piezoelectric properties. The uniqueness of this work is the simplicity of the synthesis; moreover the piezoresponse d 33 becomes giant, at around 7500 pm V-1. This response is an order of magnitude greater than that of lead zirconate titanate (PZT), which is known to be the most successful ferroelectric over the past 50 years. This concept utilizing nanoporous BCZT will be highly useful for a promising high-density electrolyte-free dielectric capacitor and generator for energy harvesting in the future.

Piezoelectric properties of (Sr0.2Ca0.8)3TaGa3Si2O14 and Ca3TaGa3Si2O14 single crystals grown via vertical Bridgman method

(Sr0.2Ca0.8)3TaGa3Si2O14 and Ca3TaGa3Si2O14 single crystals were successfully grown using the vertical Bridgman method, and the piezoelectric properties of these crystals were studied.

Electrospun polarity-controlled molecular orientation for synergistic performance of an artifact-free piezoelectric anisotropic sensor.

Anisotropy in mechanical, optical and thermal sensors in a spatial direction has many applications in health care, robotics, aerospace, and tissue engineering. In particular, wearable and implantable sensors respond to stretching and bending strains that probe mechanical energy and track physiological signals. Hence, the development of anisotropic pressure sensors with true piezoelectric (PE) signals is of utmost importance to achieve efficient devices. Herein, a simple and efficient method is developed for high longitudinal and transverse responses, with an approach to isolating a true piezoelectric signal. The electrospun (ES) polarity of oriented dipoles inside flexible fibers gives rise to a high longitudinal/transverse PE response of both lateral and transverse strains. Nanofibers of poly(vinylidene-chlorotrifluoroethylene) copolymers contain poled dipoles, up to 86%, that promote an enhanced PE coefficient of 42 pm V-1 in the case of negative polarity-based electrospinning. It is 40% higher in composition than the commonly adopted positive polarity-biased electrospinning process. We demonstrated the advantage of such a high PE coefficient by the enhanced sensitivity of the longitudinal (VLs = 0.3 V kPa-1, ILs = 0.07 μA kPa-1) as well as transverse (VTs = 1.0 V kPa-1, ITs = 0.8 μA kPa-1) PE response. To counter the ambiguity of high transverse response as compared to longitudinal in electrospun fiber-based devices, a facile method is proposed to isolate the ferroelectret, triboelectric and piezoelectric signals in a fiber-based hybrid device with their independent charge generation mechanisms.

Temperature-insensitive high piezoelectricity in a (Bi0.5K0.5)TiO3–PbTiO3–PbZrO3 ternary system

A d33 value exceeding 350 pC N−1, maintained up to 320 °C, and a large strain of 0.29% within 20% variation are achieved in a novel system of BKT–PT–PZ. The stable nanosized domains contribute to the temperature-insensitive high piezoelectricity.

A homochiral polar molecular piezoelectric material with phase transition and high piezoelectricity precisely designed by cyanomethyl group substitution

A chiral non-polar SHG inactive compound without phase transition is transformed into a chiral polar SHG active compound with phase transition by the introduction of cyanomethyl group, and the d22 value is raised significantly from 0 to 18 pC/N.

Analysis of defects in &lt;i&gt;B&lt;/i&gt;-vacancy compensated Sm-doped PZT(54/46) ceramics and their influences on piezoelectric properties

Rare earth dopping, especially samarium (Sm) dopping is considered as an effective way to obtain high piezoelectricity by increasing local structure heterogeneity in Pb-containing &lt;i&gt;AB&lt;/i&gt;O&lt;sub&gt;3&lt;/sub&gt; perovskite ceramics. Defects play an significant role in determining piezoelectric properties in aliovalent ion doping systems. In order to obtain an insight into the effect of defects, especially &lt;i&gt;B&lt;/i&gt;-site vacancies on piezoelectricity, Sm-doped PZT(54/46) ceramics compensated by &lt;i&gt;B&lt;/i&gt;-site vacancies are fabricated by conventional solid state reaction method. The influence of defects on piezoelectric properties is studied by positron annihilation lifetime spectroscopy (PALS), coincidence Doppler broadening spectroscopy (CDBS), and conventional methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), electrical performance testing on dielectricity, ferroelectricity and pizoelectricity. The XRD results show that all ceramics crystallize in a pure perovskite phase, Sm&lt;sup&gt;3+&lt;/sup&gt; doping causes a transformation from the rhombohedral to tetragonal phase and the morphotropic phase boundary (MPB) lies near Sm&lt;sup&gt;3+&lt;/sup&gt; doping content &lt;i&gt;x&lt;/i&gt; = 0.01–0.02. Electrical performance testing results indicate that with the increase of &lt;i&gt;x&lt;/i&gt;, all of the dielectricity, ferroelectricity and pizoelectricity first increase and then decrease, the sample with &lt;i&gt;x&lt;/i&gt; = 0.01 and 0.02 exhibit similar excellent dielectricity and ferroelectricity, while their pizoelectricity differs greatly, the optimal piezoelectric coefficient &lt;i&gt;d&lt;/i&gt;&lt;sub&gt;33&lt;/sub&gt; = 572 pC/N (nearly double that of undoped sample) is obtained in the sample with &lt;i&gt;x&lt;/i&gt; = 0.01. The PALS results show that Sm doping leads the defect types to change from the coexistence of &lt;i&gt;A&lt;/i&gt;-site and &lt;i&gt;B&lt;/i&gt;-site vacancies for &lt;i&gt;x&lt;/i&gt; ≤ 0.01 to mainly &lt;i&gt;A&lt;/i&gt;-site related defects for &lt;i&gt;x&lt;/i&gt; ≥ 0.02. The CDBS results further verify that the concentration of &lt;i&gt;B&lt;/i&gt;-site vacancies is highest for &lt;i&gt;x&lt;/i&gt; = 0.01 and lowest for &lt;i&gt;x&lt;/i&gt; = 0.02. It is inferred that the high pizoelectricity for &lt;i&gt;x&lt;/i&gt; = 0.01 is related to its high concentration of &lt;i&gt;B&lt;/i&gt;-site vacancies, which can dilute the number of &lt;i&gt;A&lt;/i&gt;-site vacancies and oxygen vacancies, reducing the chance of forming defect dipoles between an &lt;i&gt;A&lt;/i&gt;-site vacancy and an oxygen vacancy, facilitating domain wall motion, and enhancing piezoelectricity. This study indicates that &lt;i&gt;B&lt;/i&gt;-site vacancies can enhance piezoelectricity to some extent, which will provide some guidance for defect engineering.

Simultaneously realizing high piezoelectricity and thermal stability in BNT-based ceramics via integrating layered diffusion and thermal treatment

An inherent conflict of (Bi0.5Na0.5)TiO3-based (BNT) lead-free piezoelectric ceramics is the optimizing piezoelectric response (d33) with deteriorating depolarization temperature (Td), which severely restricts the further achievements of BNT-based ceramics. A new strategy is proposed in this work to simultaneously realize high piezoelectric property (d33 = 140 pC/N) and thermal stability (Td = 232 °C) in BNT-based ceramics by integrating layered composite structure of 0.89(Bi0.5Na0.5)TiO3-0.11BaTiO3 with high Td and 0.87(Bi0.5Na0.5)TiO3-0.11BaTiO3-0.02(Sm0.5K0.5)TiO3 with large d33 (BNT1/BNT2) and thermal treatment processes. In the layered composite ceramics, the composition difference induces a built-in field (Eb) that promotes the diffusion of ferroelectric-relaxor (FE-RE) phase transition in the ceramics, delaying the Td to 185 °C. In addition, the thermal treatment processes facilitate both the Eb expansion, stabilize the d33 over a wide temperature range, as well as enlarge the grain size to elevate the d33 from 133 pC/N to 145 pC/N. Hence, the strategy we proposed is promising to offer a new paradigm for designing piezoelectric materials with high piezoelectric response over a wide temperature range.

Optimizing solvent dipole moment enables PVDF to improve piezoelectric performance

The all-trans conformation (β-phase) possesses a significant impact on the piezoelectric polymer polyvinylidene fluoride (PVDF). Inducing more molecular chain [−CH2−CF2−]n to form all-trans conformation is one of the biggest obstacles for manufacturing high-performance piezoelectric sensing devices. Herein, the continuous vacuum technology is used to modulate the polarity of binary solvents by the proportion of the lower solvent. The regulated solvent forms a high dipole moment, an interaction between the dipole of β-phase and the dipole moment makes the phase reversal in PVDF. Fourier transform infrared spectroscopy, piezoelectric constant test and other characterization results show that when the weakly polar acetone and the strongly polar solvent DMF reach a ratio of 4:6, the pure PVDF film possesses high piezoelectricity (d 33 ∼ −44.8 pC N−1) and strong self-polarization. Additionally, the A4D6 device exhibits high sensitivity (S 1 = 0.182 V/N, 0.5 N ∼ 30 N), driven capability (0.49 mW m−2), and reliability during the electrical tests as a pressure device. This work provides an effective and cost-effective route of optimizing the solvent’s polarity to improve the piezoelectric characteristics of the polymer.

Understanding local physical properties of barium titanate ceramics depending on the synthesis conditions assisted by a machine learning algorithm

Barium titanate (BT) is widely used in electronic components, such as multilayer ceramic capacitors, owing to its high dielectric constant and piezoelectricity. The continuously increasing demand for more efficient devices has led to the development of smaller and more efficient BT ceramics by controlling the synthesis conditions. However, despite the decrease in size of BT grains to the nanoscale, the physical properties of BT ceramics have mostly been investigated on a macroscopic scale. In this study, we investigated the effects of synthesis conditions on local physical properties such as surface roughness, leakage current, and domain structure/switching using atomic force microscopy. We further applied machine learning analysis to effectively understand the effects of synthesis conditions on these physical properties; the analysis not only provides local information on BT ceramics but also a comprehensive understanding of their physical properties.

Lead zirconate titanate-based ceramics with high piezoelectricity and broad usage temperature range

Piezoceramics have long faced the challenge of achieving both a high Curie temperature (TC) and outstanding electrical properties due to thermal depolarization. To address this, we introduced a novel two-step synergistic strategy in synthesizing lead zirconate titanate (PZT)-based x[(1–y)BiYO3-yFe2O3)]-(1–x)Pb(Zr0.53Ti0.47)O3 [abbreviated as xBYF(y)-PZT] ceramics, where co-doping of Fe2O3 and BiYO3 significantly influences dielectric and piezoelectric properties. Our breakthrough composition, 0.01BYF(0.6)-PZT, showcases a unique coexistence of rhombohedral and tetragonal phases. It boasts impressive figures, including a piezoelectric coefficient d33 of 467 pC N−1, a TC of 381 °C, an electromechanical coupling coefficient (kp) of 68%, and a coercive field (Ec) of 12 kV cm−1, displaying both “softening” and “hardening” characteristics. In-depth analysis with in-situ X-ray diffraction and transmission electron microscopy unveils the critical role of multiphase coexistence and local heterostructures in enhancing piezoelectric responses through synergistic effects. Notably, this innovative composition with x = 0.01 showcases exceptional thermal stability across a broad operating temperature range (30–350 °C) and delivers an in-situ d33 value of 790 pC N−1. These compelling findings underscore the potential of BYF-modified PZT ceramics as promising candidates for high-temperature piezoelectric applications.

Critical roles of multiphase coexistence in boosting piezo-catalytic activity of BaTiO3-based piezoelectric ceramics

Recently, piezocatalysis induced by perovskite ferroelectric ceramics has widely been favored as a possible fascinating strategy for water remediation due to its low cost, simplicity and feasibility. Herein, a strategy of three-ferroelectric-phase coexistence is proposed to boost the piezocatalytic performance of BaTiO3-based ceramics by introducing Ca(Sn0.5Zr0.5)O3 into BaTiO3. The piezocatalysts of (1-x)BaTiO3–xCa(Sn0.5Zr0.5)O3 ceramics were prepared by a high-temperature solid-phase method. The phase structure, microstructure, electrical properties and catalytic performance of ceramics were comprehensively studied. As x increases from 0 to 0.10, the ceramics undergo the phase evolution from single tetragonal phase to multiphase (coexistence of rhombic, orthorhombic, and tetragonal phases). It is found that the phase structure of the ceramics plays a critical role in enhancing the piezocatalytic activity. The pure BaTiO3 exhibits the tetragonal (T) phase with few spontaneous polarization directions and high polarization rotational energy barrier, resulting in poor catalytic performance and low piezoelectricity. With the coexistence of rhombic (R), orthorhombic (O) and tetragonal (T) phases, the ceramic with x = 0.1 exhibits the increased spontaneous polarization directions and low polarization rotational energy barrier, leading to excellent catalytic performance and high piezoelectricity. Especially, for the ceramics with x = 0.10, the degradation rates of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under ultrasonication reach 97 %, 93 % and 73 %, respectively. In addition, the influencing factors of piezocatalytic degradation of RhB and the catalytic mechanism are investigated. This work proposes an environmentally friendly piezoelectric material for improving the water environment and a strategy for improving the catalytic activity of BaTiO3-based lead-free piezoelectric materials.

High Piezoelectricity of Multicomponent Lead-Based Ceramics with High Temperature Stability

High Piezoelectricity of Multicomponent Lead-Based Ceramics with High Temperature Stability

Biocompatible and stretchable piezoelectric elastomer based on lactic acid for synchronous repairing and function monitoring of volumetric muscle loss

The treatment of volumetric muscle loss (VML) and the real-time monitoring of damaged muscle function have long posed challenges for clinicians. The novel in-situ electric stimuli therapy using piezoelectric materials for VML repairing has attracted numerous attentions. However, the reciprocating motion of the muscle requires the piezoelectric materials with both high piezoelectricity and stretchability. In this study, a biocompatible piezoelectric elastomer (VMLRE) was synthesized through the copolymerization of several bio-based diacids and diols. By controlling the chemical compositions and chain structure, the VMLRE possess elastic modulus accurately matching with that of muscle tissue, allowing the reciprocal deformation during muscle movements to realize function recovery evaluating. The backbone of VMLRE is enriched with CO dipoles to achieve excellent piezoelectric properties, which enable converting mechanical stimuli generated by physical activity into electrical energy, providing real-time and in situ electrical stimulation. The electric stimulation promotes myoblast proliferation and differentiation by potentially activating calcium/calmodulin signaling pathways, facilitating cell migration, and enhancing neovascularization. Consequently, the rate of VML repair is significantly improved. Our innovative piezoelectric elastomer enables simultaneous repair and real-time biofeedback monitoring of VML, offering a novel strategy for the treatment of volumetric muscle loss.

Chiral Two-Dimensional Hybrid Organic-Inorganic Perovskites for Piezoelectric Ultrasound Detection.

Hybrid organic-inorganic perovskites (HOIPs) have exhibited striking application potential in piezoelectric energy harvesting and sensing due to their high piezoelectricity, light weight, and solution processability. However, to date, the application of piezoelectric HOIPs in ultrasound detection has not yet been explored. Here, we report the synthesis of a pair of chiral two-dimensional piezoelectric HOIPs, R-(4-bromo-2-butylammonium)2PbBr4 and S-(4-bromo-2-butylammonium)2PbBr4 [R-(BrBA)2PbBr4 and S-(BrBA)2PbBr4], which show low mechanical strength and significant piezoelectric strain coefficients that are advantageous for mechanoelectrical energy conversion. Benefiting from these virtues, the R-(BrBA)2PbBr4@PBAT and S-(BrBA)2PbBr4@PBAT [PBAT = poly(butyleneadipate-co-terephthalate)] composite films show prominent underwater ultrasound detection performance with a transmission effectivity of 12.0% using a 10.0 MHz probe, comparable with that of a polyvinylidene fluoride (PVDF) device fabricated in the same conditions. Density functional theory calculations reveal that R-(BrBA)2PbBr4 and S-(BrBA)2PbBr4 have a beneficial acoustic impedance (5.07-6.76 MRayl) compatible with that of water (1.5 MRayl), which is responsible for the facile ultrasound-induced electricity generation. These encouraging results open up new possibilities for applying piezoelectric HOIPs in underwater ultrasound detection and imaging technologies.

Corona: An effective polarization strategy of polymer composites with high-k filler for piezoelectric nanogenerators

Piezoelectric nanogenerators (PENGs) are mushrooming owing to demand of swift transformation of power supply from fossil fuel to green energy. Piezoelectric ceramics are enthusiastically chased because glorious PENGs demand for high piezoelectricity. Generally, brittleness of ceramics can be compensated by polymer, while the dielectric mismatch between low permittivity of polymer and high permittivity of ceramics plaguing researchers so long. Traditional contact poling is always interrupted by abrupt dielectric breakdown due to electric field concentration at interface between polymer and fillers. Here, we propose a strategy of using corona polarization instead of traditional contact polarization to insistently polarize large-area polymer composite films with high-k filler. The corona polarization technique can ignore the negative effect of local short circuit on polarization failure owing to prominent lateral insulation between deposited charges on surface of composites film, consequently obtaining well-performed piezoelectricity. Henceforth, polarization failure did not occur using corona even under poling voltage of 26 kV. The corona-poled PVDF/Y-ZnO PENG with only 15 wt% content of fillers generated output power density of ∼1064 μW/cm3. Our work will pilot the development of polymer composites with high-k filler and piezoelectric nanogenerators.

Energy conversion and storage in functional dielectrics

Functional dielectrics are a group of materials possessing interesting electro-active behaviors, such as variable permittivity, high breakdown strength, ferroelectricity, piezoelectricity, and pyroelectricity, resulting from their capacity to generate and respond to electric fields in a nonlinear manner. These properties make them highly desirable for energy conversion and storage applications.

Grain Boundary Diffusion Hardening in Potassium Sodium Niobate‐Based Ceramics with Full Gradient Composition and High Piezoelectricity

AbstractReducing mechanical losses and suppressing self‐heating are critical characteristics for high‐power piezoelectric applications. For environmentally friendly Pb‐free piezoelectric ceramics, traditional acceptor doping or annealing treatments have successfully improved the mechanical quality factor (Qm) based on a ceramic matrix with a poor piezoelectric coefficient (d33&lt;100 pC/N). Nevertheless, a ceramic with high Qm and d33 values has not been reported owing to the inverse relationship between Qm and d33. Herein, a novel hardening method called grain boundary diffusion is used to develop Pb‐free potassium sodium niobate ceramics, where Qm increased by more than two‐fold (from 51 to 132) and a high d33 value (d33 = 360 pC/N) is maintained. Significantly, d33 retained 98% of its initial value after 180 days, exhibiting improved aging stability. The established properties are associated with the formation of the core‐shell microstructure and the full gradient composition distribution using structural characterizations and phase‐field simulations, where the core maintains a high d33 and the shell provides a hardening effect. The novel hardening effect in piezoelectric materials, known as grain boundary diffusion hardening, highlights the enhancement of the mechanical quality factor with high piezoelectricity, providing a new paradigm for the design of functional materials.