High-performance Piezoelectric Nanogenerators Research Articles

Scalable wet-spinning multilevel anisotropic structured PVDF fibers enhanced with cellulose nanocrystals-exfoliated MoS2 for high-performance piezoelectric textiles

The high-performance fabric-based piezoelectric nanogenerators (PENGs) is the ideal choice for the next generation of wearable electronics. However, large-scale fabrication of high-performance fabric-based PENGs remains a great challenge. In this study, cellulose nanocrystals (CNCs) exfoliated MoS2 (C@M) are integrated into the poly (vinylidene fluoride) (PVDF) matrix, which are successfully fabricated PVDF/C@M fibers (PCF) by wet-spinning and post-drawing processes. Accompanied by the stress-induced anisotropic alignment of C@M and PVDF molecular chains during post-drawing, the interfacial interactions between C@M and PVDF dipoles greatly promote the formation of the electroactive β-phase of PVDF as well as the orientation of the dipoles. The PCF demonstrate excellent mechanical performance with a tensile strength of 301 MPa and toughness of 68.5 MJ·m−3. Subsequently, the PCF are woven into fabrics and subsequently assembled into a flexible PENG (PCF-PENG), exhibiting excellent piezoelectric coefficient (d33 = 40.3 pC·N−1), power density of 56.25 μW·cm−2. Furthermore, scenarios such as energy harvesting, motion detection, and posture recognition of the PCF-PENG are demonstrated, providing a feasible proposal for the large-scale fabrication of electronic textiles.

A novel PZT hollow structure utilized in high-performance piezoelectric nanogenerator

The transformation of environmentally benign waste energy into functional electricity holds profound implications for advancements in human progress. Herein, we detail the synthesis of tubular nanofibers featuring a hollow architecture through an innovative combination of sol-gel processing and electrospinning techniques, followed by surface modification with dopamine. These engineered PZT hollow nanotubes, upon integration into PVDF piezoelectric films, serve as potent reinforcing agents that amplify the piezoelectric active phase within the PVDF matrix. The introduction of these hollow PZT nanostructures alters the polarization electric field distribution, thereby augmenting the polarization dynamics of PVDF and significantly enhancing the piezoelectric performance of the resultant PVDF/PZT composite films. Our novel nano-generator exhibits an exceptional balance between a high piezoelectric coefficient, superior output characteristics, and commendable stability. Notably, the piezoelectric constant (d33) of Neat PVDF films experiences a substantial elevation from 9 pC N−1 to 20 pC N−1, representing an impressive enhancement of approximately 122 %. Furthermore, the power density achieves a value of 0.54 μW cm−2. This study introduces an effective approach to augment the productive output capability of composite nanogenerators, paving the way for sustainable energy harvesting technologies.

High performance piezoelectric nanogenerator by fiber microstructure engineering toward self-powered wireless sensing system

Piezoelectric nanogenerator (PENG) with these advantages of low cost, small volume and stable output in extreme environment is constantly required to develop self-powered sensing system in Internet of Things (IoT), which can relieve energy crisis and reduce labor maintenance costs. However, low electrical output of PENG severely restricts its application and has been a key challenge in the development of PENG. To attain high output performance, a new PENG based on core-shell heterostructure of barium titanate(BT)/polyvinylidene fluoride(PVDF) composite fibers coated with BT@Ag was designed for energy harvesting and wireless sensing application. The outputs of PENG with this special structure are enhanced near 3 times than that of PENG based on traditional fibers, benefiting from the enhanced induced-polarization and stress transfer mechanism in PENG, which is confirmed by experimental results and explained by multi-physics simulations. Moreover, the PENG can effectively harvest wind and acoustic energy, which can deliver the high outputs of 107.5 V and 16.18 µA under 12 m/s wind speed, 45.4 V and 6.5 µA under 110 dB sound pressure, respectively. To verify the practicability of the PENG, a whole self-powered wireless sensing system based on the PENG to harvest energy in environment was demonstrated, where the signal of humidity condition of soil can be sensed periodically and transmitted to mobile phone for further analysis. This work provides an effective strategy to boost performance of PENG and further paves a route about advanced self-powered wireless sensing technology in IoT.

Enhancement of the piezoelectric performance of GN nanosheets/PVDF nanocomposite film using electrostatic layer and penetrated electrode

The efficiency of the piezoelectric nanogenerator is a vital factor for the superior performance of the nanogenerator to achieve a green and eco-friendly technology in the development of modern electronics. Piezoelectric nanogenerators (PNGs) have limited use in mechanical energy harvesting due to their low output performance. The output has been a major source of concern for PNG's development. A new design of PNG based on g-C3N4 nanosheets(GN)/PVDF nanocomposite film (GPNC) using penetrated Cu electrode and electrostatic layer is proposed to overcome this problem. By creating numerous peripheral contacts within the piezoelectric material, the overall number of surface polarization charges increased. Also, an electrostatic contribution from graphene oxide contributes to an increased output voltage. The syngeristic effect of high % γ-nuclei, penetrated electrode, and electrostatic effect is supposed to vital for carry out significant piezoelectric outputs (V∼34.4 V and I ∼3.2 µA) and superior force sensitivity (0.93 V/kPa). In practical applications, the designed PNG can competently harvest electrical energy from various human movements, and also can detect low physiological actions. Our work offers a simple but effective perspective for high-performance piezoelectric nanogenerator fabrication and progress a stride toward self-powered day-to-day used electronics.

Optimized performance of self-driven piezoelectric sensors through KNN/Nb2CTx synergistic effect

Flexible high-performance piezoelectric nanogenerator (PENG) excel in converting mechanical energy into electrical energy and exhibit remarkable sensitivity, a feature that is paramount for the development of self-driven piezoelectric sensors. In this study, electrospinning technology was used to prepare poly (vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] based piezoelectric nanofiber composite films containing potassium-sodium niobate nano particles (KNN NPs) and Nb2CTx co-doping, as well as single-component doping. The co-doped composite film attained an optimal β-phase content of 91.33%. Owing to the enhanced dipole alignment and interface charge polarization, the piezoelectric performance of the co-doped composite film was significantly enhanced compared to that of single-component doping. The co-doped piezoelectric composite film displayed a stable maximum output voltage of 20 V and an output current of 1.46 μA. The peak instantaneous power output was measured at 9.9 μW under the optimal resistive load of 10 MΩ. Durability testing over 2000 cycles affirmed the excellent mechanical stability of the piezoelectric composite film. Moreover, the fabricated piezoelectric composite film showed considerable potential in applications such as monitoring human activities and serving as an early warning system for natural disasters such as landslides, as indicated by the test results.

High-Performance Piezoelectric Nanogenerator Based on Odd–Odd Nylon Nanofibers for Wearable Electronics via Precise Control of Ferroelectric Phase and Orientation

High-Performance Piezoelectric Nanogenerator Based on Odd–Odd Nylon Nanofibers for Wearable Electronics via Precise Control of Ferroelectric Phase and Orientation

A novel centrifugal electrospinning design for preparing of high alignment β-phase PVDF nanofibers for high-performance piezoelectric nanogenerators

The effects of polyvinylidene fluoride (PVDF) wt. % and electric fields on the production of PVDF fibers using a novel centrifugal electrospinning design were investigated. High-quality, bead-free fibers with diameter of (0.55 ± 0.04) μm were successfully produced. Fibers with exceptionally high β-phase content of 96.1 % and piezoelectric coefficient, d33 of (−157 ± 5) pC N−1 were obtained using PVDF amount and electric field of 14.0 wt % and 400 V cm−1, respectively. Under 3.0 N repetitive vertical forces, the fabricated piezoelectric nanogenerator (PENG) exhibited impressive open-circuit voltage, short-circuit current and power density of (32.6 ± 0.7) V, (3.26 ± 0.07) μA and (15.4 ± 0.6) μW cm⁻2, respectively. The production of high and well aligned β-phase in the fibers indicated by good d33 values are the likely reasons for the excellent performance of the PENG. Ultimately, potential of the fabricated PENG as a self-power supply for low-energy electronic devices was demonstrated.

High-Performance Piezoelectric Nanogenerator of BTO-PVDF Nanofibers for Wearable Sensing.

Piezoelectric nanogenerator (PENG) produces stable electrical signals in response to external mechanical stimuli and holds promise in the fields of flexible sensors and smart wearable devices. In practice, a high-performance PENG with a straightforward structure and exceptional reliability is deeply desired. This study optimally synthesizes piezoelectric composites comprising polyvinylidene fluoride (PVDF) incorporated with barium titanate (BTO) nanoparticles (NPs) and fabricated a PENG with heightened sensitivity by using the electrospinning technique. The polar β-phase content of the dual-optimized BTO-PVDF (barium titanate and polyvinylidene fluoride) electrospun fiber reaches up to 82.39%. In the bending mode, it achieves a remarkable maximum open-circuit voltage of 19.152V, a transferred charge of 8.058 nC, and an output voltage per unit area of 2.128Vcm- 2. Under vertical pressure conditions, the BP-PENG exhibits an impressive voltage of 12.361V while the force is 2.156 N, demonstrating a notable pressure sensing sensitivity of 5.159VkPa-1, with an excellent linear relationship. Furthermore, the BP-PENG displays sensitive sensing features in monitoring hand movements. The sensitive response and high performance make it promising for applications in human motion monitoring and smart wearable devices.

The construction of BaTiO3-based core-shell composites for high-performance and flexible piezoelectric nanogenerators

The construction of BaTiO3-based core-shell composites for high-performance and flexible piezoelectric nanogenerators

Performance of flexible ZnO nanowire piezoelectric generators enhanced by bifacial superposition

High performance piezoelectric nanogenerators have important applications in many fields. In this work, we report a bifacial superposed zinc oxide piezoelectric nanogenerator that shows better performance than a single unit. A stainless steel substrate with both front and back zinc oxide nanowire arrays is an elementary unit. Then we engage in an alternating superposition of two elementary units with a carbon-contained polyurethane foil. Multiple units can be similarly assembled by adding alternating structures to further enhance the piezoelectric output performance. Nanogenerators obtained by the above bifacial method are flexible and stability with high output. The method can be used to increase the overall piezoelectric performance and is expected to have a wide application in self-powered device fields.

High-performance piezoelectric nanogenerators based on Cs2Ag0.3Na0.7InCl6 double perovskites with high polarity induced by Zr/Te codoping

Piezoelectric nanogenerators (PENGs), which operate based on mechanical-to-electrical energy conversion, have been widely explored for exciting applications in modern devices such as wearable electronics, self-powered sensors, and energy harvesters. Herein, we report on high-performance PENGs based on Cs2Ag0.3Na0.7InCl6 double perovskite (CDP) within a polyvinylidene fluoride (PVDF) matrix, which exhibit enhanced polarity due to rationally designed Zr/Te codoping. As a proof of concept, the resultant PENGs based on Zr/Te codoped CDP@PVDF deliver an excellent piezoelectric output, with a maximum open-circuit voltage and short-circuit current density of 67 V and 18 μA·cm−2. This level of performance is ∼19 and ∼12 times higher than PVDF-based PENGs with no CDP, and ∼2 and ∼4 times higher than CDP@PVDF-based PENGs without doping or with single Te doping, and ∼1 and ∼2 times higher than CDP@PVDF-based PENGs with single Zr doping, respectively. Moreover, the as-assembled PENGs exhibit impressive potential in wearable energy harvesters, motion sensors, and DC-power devices with robust stability, underscoring their bright future toward practical applications.

Lead-free Bi2CuO4 interspersed into PDMS matrix-based bifunctional piezoelectric nanogenerator for vibrational energy harvesting and visible light photodetection applications

Lead-free materials with superior piezoelectric properties are gaining much interest due to their high performance and increased long-term sustainability. In this context, bismuth-based ternary oxides exhibit perovskite crystal structures with high piezoelectric coefficients and mechanical damping. Thus, in this work, we report a Bi2CuO4: Polydimethylsiloxane (BCO: PDMS) composite -based photoinduced-piezoelectric nanogenerator for harvesting weak mechanical vibrations which are abundant in the atmosphere. Notably, the BCO nanoparticles exhibit a highly crystalline tetragonal structure with 2D-nanoflake-like morphology providing a high surface area for the PENG applications. Further, the optical studies of BCO illustrate an enhanced absorption in the visible region with a bandgap of 2.5 eV. BCO: PDMS-based PENG displays a maximum open circuit voltage of 50 V and short circuit current of 300 nA upon application of 0.15 kgf vertical compressive force without any electrical poling. The PENG device exhibits an 18 % increment in output voltage upon illumination of visible light of 5 mW/cm2 intensity with superior photodetection properties. The obtained response can be attributed to the synergistic effect, i.e., the generation of exciton pairs upon illumination and separation of charge carriers due to the inbuilt piezoelectric field. Moreover, the PENG exhibits a distinct and accurate response for feeble and subtle frequencies in the range of 3–22 Hz such as atmospheric noise, and gravity hum noise. thus, proving the superior sensitivity. The fabricated PENG device displayed a stable response for 30 min of continuous vibration displaying superior cyclic stability. This work demonstrates a combination of perovskite crystalline material and PDMS leading to the development of high-performance piezoelectric nanogenerators with future scope in frequency detection systems for security and safety applications.

Design and fabrication of self-powered flexible P(VDF-TrFE)/ZnO/TiO2 fiber mats as nanogenerator for wearable applications

Polymer-based nanocomposite fibrous membranes are the basis of wearable flexible devices, but the application of high voltage poling, brittle material as dopants, or toxic compounds is the main challenge in the development of such devices. P(VDF-TrFE)/ZnO/TiO2 electrospun nanofiber mats are used in here to fabricate self-poled, lead-free, and flexible piezoelectric nanogenerators. Herein, self-poled, lead free, and flexible high performance piezoelectric nanogenerators (PENGs) are designed using the P(VDF-TrFE)/ZnO/TiO2 electrospun fiber mats. Three phase nanocomposite mats with varying TiO2 concentrations are fabricated using far-field electrospinning method. In this study, we reported the effect of ZnO and TiO2 nanoparticles on the viscoelastic property and piezoelectric output. The electroactive beta (β) phase fraction of P(VDF-TrFE) mats are observed to be enhanced as a result of the dispersion of TiO2 nanoparticles into the three phase nanocomposite films. The dielectric and viscoelastic properties are improved with the addition of TiO2 nanoparticles. The designed piezoelectric device produced short circuit current, open circuit voltage, and piezoelectric peak power of 4.16 μA, 23 V, and 95.68 μW, respectively. These piezoelectric outputs are obtained with the optimization of TiO2 concentration and the PENG devices are subjected to elbow bending, wrist bending, and finger tapping. The piezoelectric output of three phase composite mats is almost 3.6 times higher than PENG made from P(VDF-TrFE) fiber, and the increment in the performance is due to the synergistic effect of ZnO and TiO2 in the P(VDF-TrFE) polymer matrix. PENG is used to display real-time demonstrations of body movement detection and biomechanical energy harvesting to power an LED bulb. The enhanced performance and robustness of the nanogenerator make the electrospun P(VDF-TrFE)/ZnO/TiO2 mat an excellent candidates for sensing and energy harvesting applications.

3D printing of PVDF-based piezoelectric nanogenerator from programmable metamaterial design: Promising strategy for flexible electronic skin

The high-performance piezoelectric nanogenerator (PENG) with good flexibility, tunability and sensitivity is desirable for the next-generation of wearable electronics. However, the 3D printing of unique architectures and arbitrary shapes could endow the conformal electronic sensors with excellent flexibility and functionality. In this work, the self-poled PENG were successfully fabricated by incorporating the oriented ionic salt-montmorillonite (IS-MMT) co-fillers into poly (vinylidene fluoride) (PVDF) matrix and then performing 3D printing. This hence could give the 3D printed PENG the locked interfacial piezoelectric polarization. More importantly, the self-adaptive conformal PENG based on auxetic metamaterial has also been developed, which is beyond the practicability of the traditional 2D PENG. The effect of various architectures of the metamaterial on the mechanical and piezoelectric responses was particularly discussed. The tailoring of the 3D printed cell with metamaterial of serpentine geometries shows the appealing advantages of high sensitivity to structure variation, thus being beneficial for easier regulation of piezoelectric output. When mounted on the joints as a wearable healthcare monitoring device, this 3D printed PENG could accurately detect the movement of muscles, demonstrating its potential in motion tracking and sign-language interpretation. Obviously, this work could provide a new idea for design and fabrication of programmable wearable electronics.

High Performance and Direct Current Piezoelectric Nanogenerators Using Lithium‐Doped Zinc Oxide Nanosheets

The wurtzite structured zinc oxide has been studied extensively because of its unique characteristics, such as transparency, semiconducting properties, and excellent piezoelectricity. However, the defects that are inevitably present in ZnO grown by the aqueous solution method generate excessive free electrons, which reduce the piezoelectric potential by the screening effect, thus reducing the piezoelectric output performance. Herein, direct current high‐performance piezoelectric nanogenerators (PENGs) based on Li‐doped ZnO nanosheets are demonstrated. Doping with the p‐type dopant Li reduces the number of free electrons in ZnO, minimizing the screening effect and improving the piezoelectric output performance. First, Li‐doped ZnO nanosheet is synthesized at various Li concentrations using the aqueous solution method. The doping effect on the morphology and crystal structure of the ZnO nanosheet is investigated via scanning electron microscopy and X‐ray diffraction. X‐ray photoelectron spectroscopy confirmed that the ZnO nanosheet is doped with lithium. The Li‐doped ZnO nanosheet‐based PENG produce an output power of 6.552 mW cm−2, that is, a 16‐fold enhancement in output power compared to that of the undoped ZnO nanosheet‐based PENGs.

High-performance piezoelectric nanogenerators based on hierarchical ZnO@CF/PVDF composite film for self-powered meteorological sensor

A high-performance piezoelectric sensor was fabricated for the real-time monitoring of meteorological wind and rainfall.

Charge-Boosting Strategy for Wearable Nanogenerators Enabled by Integrated Piezoelectric/Conductive Nanofibers.

The surface charge density enhancement by incorporating conductive paths into organic/inorganic piezoelectric composites is considered to be an effective way to achieve high-performance piezoelectric nanogenerators (PENGs). However, it is challenging to boost the charge density of aligned piezoelectric nanofibers due to the difficulty in efficiently building well-distributed conductive paths in their dense structure. In this work, a charge boosting strategy was proposed for enhancing the surface charge density of aligned piezoelectric nanofibers, that is, synchronously preparing piezoelectric/conductive hybrid nanofibers to realize the effective conductive paths for transferring the underlying charges to the surface of the PDMS/BaTiO3 composites. To this end, antimony-doped tin oxide (ATO) conductive nanofibers and barium titanate (BaTiO3) piezoelectric nanofibers with the same preparation conditions were selected and synchronously prepared by the polymer template electrospinning technology, followed by the calcination process. Benefiting from the well-distributed conductive paths for transferring the charges, the open-circuit voltage and short-circuit current of a PENG with 12 wt% ATO in hybrid nanofibers reached 46 V and 14.5 μA (30 kPa pressure), respectively, which were much higher than the pristine BaTiO3-based PENG. The high piezoelectric performance of the developed PENGs guaranteed their great potential applications in powering wearable microelectronics and monitoring human activity. This charge boosting strategy via the piezoelectric/conductive hybrid nanofibers may inspire the further development of high-performance energy harvesting technology.

High-Performance Piezoelectric Nanogenerator Based on Low-Entropy Structured Nanofibers for a Multi-Mode Energy Harvesting and Self-Powered Ultraviolet Photodetector

High-Performance Piezoelectric Nanogenerator Based on Low-Entropy Structured Nanofibers for a Multi-Mode Energy Harvesting and Self-Powered Ultraviolet Photodetector

Effects of biomimetic cross-sectional morphology on the piezoelectric properties of BaTiO3 nanorods-contained PVDF fibers

In this study, the effects of the morphology of components on the performance of a piezoelectric nanogenerator were investigated. Polyvinylidene fluoride (PVDF) fibers with biomimetic cross-sectional morphologies inspired by plants were fabricated by integrating melt spinning, winding, and corona poling. The cross-sectional morphology of the PVDF fiber significantly influenced the piezoelectric performance because of differences in the exterior surface area and contact volume, which are important in the production of β-phase PVDF and crystallinity. The daffodil flower-shaped PVDF fiber exhibited the best piezoelectric performance among the PVDF fibers with various biomimetic cross-sectional morphologies (i.e., daffodil flower, radish flower, papyrus stem, and stalk grain stem) possessing different active areas for piezoelectricity generation. Its open-circuit voltage of 36.05 V and short-circuit current of 3.126 μA are attributable to its highest exterior surface area and contact volume, which maximize the active area (deformation area) for piezoelectricity generation. The effect of the morphology (nanoparticles and nanorods) of BaTiO3, which is another component of the piezoelectric nanogenerator, was also investigated using BaTiO3-contained PVDF fibers involving the daffodil flower-like cross-sectional morphology, namely, the PVDF-daffodil/BaTiO3 nanoparticle (NP) and PVDF-daffodil/BaTiO3 nanorod (NR). Compared with nanoparticles, the rod morphology more efficiently promoted asymmetry in the fiber during fabrication. The PVDF-daffodil/BaTiO3 NR produced an excellent open-circuit voltage of 62 V and a maximum power of 91 μW from human motion. This study provides new insights for the practical mass production and utilization of high-performance piezoelectric nanogenerators.

Poly(vinylidene fluoride)-Stabilized Black γ-Phase CsPbI3 Perovskite for High-Performance Piezoelectric Nanogenerators.

Halide perovskite materials have been recently recognized as promising materials for piezoelectric nanogenerators (PENGs) due to their potentially strong ferroelectricity and piezoelectricity. Here, we report a new method using a poly(vinylidene fluoride) (PVDF) polymer to achieve excellent long-term stable black γ-phase CsPbI3 and explore the piezoelectric performance on a CsPbI3@PVDF composite film. The PVDF-stabilized black-phase CsPbI3 perovskite composite film can be stable under ambient conditions for more than 60 days and over 24 h while heated at 80 °C. Piezoresponse force spectroscopy measurements revealed that the black CsPbI3/PVDF composite contains well-developed ferroelectric properties with a high piezoelectric charge coefficient (d33) of 28.4 pm/V. The black phase of the CsPbI3-based PVDF composite exhibited 2 times higher performance than the yellow phase of the CsPbI3-based composite. A layer-by-layer stacking method was adopted to tune the thickness of the composite film. A five-layer black-phase CsPbI3@PVDF composite PENG exhibited a voltage output of 26 V and a current density of 1.1 μA/cm2. The output power can reach a peak value of 25 μW. Moreover, the PENG can be utilized to charge capacitors through a bridge rectifier and display good durability without degradation for over 14 000 cyclic tests. These results reveal the feasibility of the all-inorganic perovskite for the design and development of high-performance piezoelectric nanogenerators.