Porous flexible molecular-based piezoelectric composite achieves milliwatt output power density | Nature Communications

Oct 25, 2024

Nature Communications volume 15, Article number: 8636 (2024) Cite this article

1415 Accesses

1 Altmetric

Metrics details

Molecular ferroelectrics have made breakthrough progress in intrinsic piezoelectric response that can be on par with advanced inorganic piezoelectric ceramics. However, their successful applications in high-density energy harvesting and self-powered flexible devices have been great challenge, owing to the low elastic moduli, intrinsically brittle, and fracture proneness of such material systems under mechanical loading. Here, we have developed a flexible porous composite piezoelectric material by using soft thermoplastic polyurethane (TPU) and molecular ferroelectric materials. Benefiting from the porous structure of TPU, the flexible piezoelectric composites enable effectively large doping ratio (50%) of [Me3NCH2Cl]CdCl3 (TMCM-CdCl3) and highly efficient stress absorption, coupled with the excellent piezoelectric properties of TMCM-CdCl3, to realize a superior power density (636.9 µW cm−2 or 1273.9 µW cm−3). This output is 2000 times higher than that of flexible piezoelectric materials represented by poly(vinylidene fluoride) (PVDF). We believe that the outstanding performance of the porous composite piezoelectric material would pave a feasible way for real industrial applications of molecular ferroelectrics.

Piezoelectricity, as one of the key capabilities of ferroelectrics, plays a crucial role in broad uses of energy harvesting1,2,3,4,5,6, transducer7,8,9,10, sensing11,12,13, catalysis14,15,16, etc. Since the piezoelectricity of quartz crystals discovered by Curie brothers in 188017, extensive studies and related applications have been long dominated by perovskite oxides represented by barium titanate (BTO)18,19 and lead zirconate titanate (PZT)20,21,22,23 due to their outstanding properties including high piezoelectric coefficients, stability, and electricity generation capabilities. The growing demand for flexible and wearable devices has prompted the exploitation on composite materials combining flexible polymer substrates and inorganic ceramic piezoelectrics, to address their issue of mechanical rigidity24,25,26,27. However, their structural disparities create new thorny problems like phase separation, non-uniform stress distribution, and limited composite ratios that severely impede device performance.

Compared to the mismatch between inorganic ceramics and polymer substrates, the relative softness and compatibility of organic-inorganic hybrid materials bring great prospects for composite piezoelectric substances28,29,30,31,32,33,34. One of the notable advantages is their ability to form intermolecular forces with polymer matrices to address issues like phase separation35. But for a long time in the past organic-inorganic hybrid piezoelectric materials generally suffer from the defect of weak piezoelectric response. TMCM-CdCl336,37,38 and its solid solution (TMFM)0.26(TMCM)0.74CdCl3 (TMFM = trimethylfluoromethyl ammonium [Me3NCH2F]+) and (TMCM = trimethylchloromethyl ammonium [Me3NCH2Cl]+)39, whose piezoelectric performance can be on par with those of inorganic ceramics BTO and PZT respectively. These attributes ignite people’s enthusiasm for exploration on composite piezoelectric substances based on organic-inorganic hybrid materials40,41,42,43,44. For example, Bu et al45. reported a kind of composite piezoelectric material, which is composed of polydimethylsiloxane (PDMS) and (BTMA)2CoBr4 (BTMA = benzyltrimethyl ammonium), achieving short-circuit current of 4.24 μA, and power density of 11.72 μW cm−2 when the mass fraction of molecular ferroelectrics is 10 wt%. Furthermore, Li et al35. reported energy harvesting devices made by the composite films of TMCM-CdCl3 and PDMS, showing a high power density up to 115.2 µW cm−2. Despite of this progress, there are two significant issues with such dense polymer structures that cannot be ignored: the first aspect is the limited doping proportion of hybrid piezoelectric materials that usually unevenly dispersed, while excess will be detrimental to flexibility; another is the uneven stress distribution and low-stress absorption efficiency under external forces. These would be reflected in the final devices that exhibit unfavorable fatigue resistance and limited performance output.

Promising solution would be found in porous material like thermoplastic polyurethane (TPU) sponge, taking the advantages of light-weight, cost-effective, corrosion resistance, excellent flexibility, and stretchability46,47,48. Due to the presence of the porous structure, compared to dense materials, TPU-polymer substrate shows superior compressibility, response stability, and large composite ratios49,50,51, enabling better device performance output as demonstrated in [C(NH2)3]ClO4-TPU array52. In this study, we have constructed a porous composite piezoelectric material by incorporating soft polyurethane and molecular ferroelectric materials (TMCM-CdCl3) instead of a simple mixture of the two systems. COMSOL finite element analysis reveals that the three-dimensional interconnected skeleton structure of porous thermoplastic polyurethane plays a vital role in absorbing mechanical energy, endowing flexible piezoelectric composites with high power density, sensitivity, and fatigue resistance. Under periodic external stimulation, the flexible piezoelectric composites with the molecular ferroelectric content reach 50% exhibit remarkable output voltage (103 V), current (42 μA), and power density (636.9 µW cm−2). This power density surpasses poly(vinylidene fluoride) (PVDF), a typical flexible piezoelectric material, by more than 2000 times53, setting a new standard for organic-inorganic hybridized molecular ferroelectric composites. This outstanding power density output effect holds significant promise for advancing the application of molecular ferroelectric materials in the realm of flexible piezoelectric devices.

The primary challenge lies in the phase separation between the piezoelectric component and the flexible substrate during composite processing, attributed to the weak intermolecular forces between the two. The unique organic and inorganic hybrid structure of TMCM-CdCl3 ferroelectric molecules enhances their organic compatibility. Molecular dynamics simulations (LAMMPS) were conducted to validate their advantages in composite processing with flexible polymer substrates (TPU), as depicted in Fig. 1a. The simulation results demonstrate a robust interaction between TMCM-CdCl3 and TPU, ensuring close molecular chain integration and uniform dispersion, thus mitigating the phase separation issue. However, a persistent challenge in piezoelectric material utilization remains: how to efficiently convert mechanical energy into electrical energy to achieve higher output power density. Porous materials inherently offer superior mechanical energy absorption efficiency due to their flexible porous structure characteristics, as depicted in Fig. 1c. Leveraging these features, a porous composite strategy is proposed in this study (Fig. 1), aiming to enhance the output power density of flexible piezoelectric materials significantly. The detailed fabrication method is shown in the Supplemental Information (Supplementary Fig. 1).

a Molecular dynamics simulation of super-strong intermolecular forces between thermoplastic polyurethane (TPU) and [Me3NCH2Cl]CdCl3 (TMCM-CdCl3) materials. b Porous composite piezoelectric materials were prepared by TMCM-CdCl3 and TPU. c Advantages of porous materials, high mechanical energy absorption efficiency.

The freeze-drying method was employed to synthesize porous TPU, showcasing remarkable porosity and exceptional compressibility. Even under multiple successive rapid large strain compressions, the porous composite piezoelectric material retains its elasticity, as illustrated in Fig. 2a. Notably, the outstanding porosity properties of the porous TPU enable it to accommodate a higher proportion of the piezoelectric component, thereby enhancing the piezoelectric output performance while retaining exceptional flexibility. Furthermore, TMCM-CdCl3, characterized by a large piezoelectric coefficient (d33) of 220 pC N−1, was synthesized via solvent evaporation as the piezoelectric source. Leveraging this, a series of TMCM-CdCl3/TPU porous composites with varying mass percentages (30%, 40%, 50%, 60%, and 70%) were synthesized to explore the impact of different mass ratios of TMCM-CdCl3 on the morphology and piezoelectric performances of the composites.

a Optical photographs (scale bar: 1 cm) of a representative TMCM-CdCl3/TPU porous composites, showing excellent compression and recovery reversibility. b Packing view of the crystal structure of TMCM-CdCl3. c XRD patterns of TMCM-CdCl3, the TPU sponge, and the TMCM-CdCl3/TPU hybrid. d FE-SEM micrograph (scale bar: 10 µm) of the 50 wt% TMCM-CdCl3 hybrid sponge. e–j EDS mapping (scale bars: 50 µm) of a 50 wt%TMCM-CdCl3/TPU hybrid sponge.

The structure of TMCM-CdCl3, illustrated in Fig. 2b, depicts Cd2+ coordinating with six Cl- ions to form octahedrons. These CdCl6 octahedrons share face arrangements, creating one-dimensional CdCl3 chains, with the organic component TMCM occupying the spaces within these chains. Powder X-ray diffraction (PXRD) analysis revealed characteristic diffraction peaks corresponding to both TPU and TMCM-CdCl3 in the porous composites with different mass ratios, confirming the successful integration of ferroelectric molecules into the highly porous TPU matrix (Fig. 2c). Moreover, PXRD analysis demonstrated an increase in peak intensities of the ferroelectric molecules as the mass ratio of TMCM-CdCl3 increased from 30 wt% to 70 wt%. Field Emission Scanning Electron Microscopy (FE-SEM) was utilized to observe the cross-section of the porous composites. Figure 2d exhibits electron microscopy patterns of the composite with 50 wt% TMCM-CdCl3, revealing pore sizes ranging from 20 to 30 µm within the TPU matrix, with ferroelectric crystals distributed throughout these pores. At lower proportions of ferroelectric crystals, the pore size remains uniform, and the ferroelectric molecules are evenly dispersed throughout the porous TPU matrix. However, as the proportion of TMCM-CdCl3 increases, the pore-like structure of the TPU matrix becomes disrupted, resulting in inconsistent pore sizes and localized aggregation of ferroelectric molecules, leading to poor dispersion (Supplementary Fig. 2). Energy dispersive spectroscopy (EDS) mapping (Fig. 2e–j) indicates the presence of five main elements: C, O, Cl, N, and Cd, uniformly distributed in the skeleton, confirming the presence of TMCM-CdCl3 crystals on the TPU skeleton. The chemical composition of these elements remains unaffected by the presence of TPU. FE-SEM and EDS mapping results affirm the successful recombination of TMCM-CdCl3 in TPU, with TPU maintaining a uniform pore size at lower proportions of ferroelectric crystals.

To investigate the intermolecular forces between TMCM-CdCl3 molecules and TPU, molecular dynamics simulations were conducted using the large-scale atomic molecular massively parallel simulator (LAMMPS)54. The simulations employed universal force field (UFF), applicable to almost all elements of the periodic table55. The simulation system comprised 10 TPU chains, each with 10 repeating units, positioned above TMCM-CdCl3 (Fig. 3a), with a 1:1 mass ratio. The system’s energy was minimized using the conjugate gradient algorithm to achieve equilibrium structure. Subsequently, the system was equilibrated under the NVT ensemble for 1000 ps at 293 K, with a time step of 0.5 fs, and temperature controlled by a Nosé-Hoover thermostat. The interaction energy between the TPU and the TMCM-CdCl3 was calculated based on the following Eq. (1):

where \({{{{\boldsymbol{E}}}}}_{{{{\bf{interaction}}}}}\), \({{{{\boldsymbol{E}}}}}_{{{{\bf{TPU}}}}}\) and \({{{{\boldsymbol{E}}}}}_{{{{{\bf{TMCM}}}}{{{\boldsymbol{-}}}}{{{\bf{CdCl}}}}}_{{{{\boldsymbol{3}}}}}}\) are the potential energies of the TPU/TMCM-CdCl3 nanocomposite, the TPU, and the TMCM-CdCl3, respectively. Figure 3b, c and d shows the changes of the potential energies of the TMCM-CdCl3, the TPU, and the TPU/TMCM-CdCl3 nanocomposite during simulations, respectively. The potential energies of the TMCM-CdCl3, and the TPU and the TPU/TMCM-CdCl3 nanocomposite approach some certain values, indicating that all the three systems reach the equilibrium states at the end of the simulations. Then, the values of the potential energies of the systems at the end of the simulations were used to calculate the \({{{{\boldsymbol{E}}}}}_{{{{\bf{interaction}}}}}\) based on the above equation, and the corresponding results were listed in Supplementary Table 1. Supplementary Table 1 proved that the value of \({{{{\boldsymbol{E}}}}}_{{{{\bf{interaction}}}}}\) is −21023.05 Kcal·mol−1. That is, a strong interaction exists between the TPU chains and the TMCM-CdCl3 due to the presence of the hydrogen bonds and polar interactions between the TPU chains and the TMCM-CdCl3. As shown in the Supplementary Movie 1, during simulations the TMCM-CdCl3 molecules gradually mix with the TPU chains, also demonstrating that there are strong interactions between the TPU chains and the TMCM-CdCl3.

a The Snapshot of the beginning and end of the initial simulation system including the TPU chain and TMCM-CdCl3. b–d The changes of the potential energies of the TMCM-CdCl3, the TPU, and the TPU/TMCM-CdCl3 nanocomposite during simulations. e Potential energy between TPU/TMCM-CdCl3.

To assess the piezoelectric output performance of the porous composites, sandwich-structured piezoelectric devices were fabricated with a diameter of 1.5 cm and a thickness of 0.5 cm. Copper foils served as electrodes on the top and bottom surfaces of the porous composites. These devices underwent testing where an 80 N force was applied at a frequency of 10 Hz. The induced voltage signals were carefully observed and recorded using a signal collector, as shown in Supplementary Fig. 3. The device composed of 50 wt% TMCM-CdCl3/TPU exhibited optimal piezoelectric performance, yielding a maximum open-circuit voltage (Voc) and short-circuit current (Isc) of up to 103 V and 42 µA, respectively (Fig. 4a and c)56. Polarity switching tests confirmed the piezoelectric nature of the devices, demonstrating positive signals in the forward connection and reversed signals in the reverse connection (Fig. 4a, c and Supplementary Fig. 4). To provide a detailed analysis, magnified plots of the voltage signals (Fig. 4b and d) illustrated both positive and negative signals for each compression and release process, the piezoelectric mechanism is shown in the Supplementary Fig. 4. The voltage signals were solely attributed to TMCM-CdCl3, evidenced by a blank control using pure porous TPU without the piezoelectric source. The voltage output of the devices increased with the mass fraction of TMCM-CdCl3, albeit with stability issues observed at mass fractions of 60 wt% and 70 wt%. (Fig. 4e) This instability resulted from disruptions in the pore size distribution of the TPU matrix as a higher content of ferroelectric molecules led to uneven dispersion and stress transfer blockage. Despite these challenges, the devices maintained stability over 10, 000 cycles without significant voltage decrease (Supplementary Fig. 5). And the cross-sectional images of composite before and after the cycle have no obvious damage, as shown in Supplementary Fig. 9. Due to its outstanding piezoelectric output performance and stability, devices with 50 wt% TMCM-CdCl3 were selected for all subsequent tests.

a, b Variation of open circuit voltage over time in forward and reverse connections and detailed magnified images (Including piezoelectric device model). c, d Variation of short circuit current over time in forward and reverse connections and detailed magnified images (Including piezoelectric device model). e Open circuit voltage of piezoelectric composites with different contents. f Comparison of power density of the piezoelectric composite materials with previously reported works27,35,57,58,59,60,61. g Direct lighting of 36 white LEDs without bridge rectifiers and capacitors.

Considering the practical application scenarios, the power output density feature becomes crucial. The 50 wt% TMCM-CdCl3/TPU composites were subjected to testing under resistances ranging from 1 to 30 MΩ. Subsequently, the power density was calculated using the Eq. (2):

where V represents the voltage, R is the corresponding external load resistance, and S denotes the stimulus area. With a resistive load of 5 MΩ, the device generated a maximum instantaneous power density of 636.9 µW cm−2 (Supplementary Fig. 6). Moreover, we also tested the power density at different temperature and pressure loads, as shown in Supplementary Fig. 8. Notably, this power density is up to hundreds of times higher than what has been previously reported for molecular ferroelectric composites with organic-inorganic hybridization, even surpassing some flexible composites prepared from inorganic ceramics (Fig. 4f)27,35,57,58,59,60,61. Also, more detailed power density comparison data is listed in the supplemental information (Supplementary Tables 2 and 3).

The outstanding power density of the device sparked further exploration into its potential applications. With such remarkable power density, the best-performing device was capable of directly driving 36 series-connected white LEDs without the need for external capacitors and bridge rectifiers (Fig. 4g). The notable piezoelectric output power of porous composites can be attributed to two main factors. Firstly, molecular dynamics calculations revealed the presence of intermolecular forces between the piezoelectric component TMCM-CdCl3 and the TPU matrix, resulting in strong compatibility between the two materials and effectively mitigating phase separation issues. Additionally, the porous TPU skeleton structure possesses advantages such as better stress transfer and stress amplification, enabling more effective absorption and transfer of mechanical energy to the piezoelectric element, thereby further enhancing the overall performance of the composite.

To further validate the advantages of porous materials and their impact on the electric generation effect, COMSOL simulations were conducted comparing traditional film materials with porous materials (as described in this study) (Fig. 5). During the modeling process, the porous piezoelectric composite material was represented using a “Weaire-Phelan” structural array62, which forms a three-dimensional interconnected skeleton structure, while the traditional film material was modeled as a solid block structure. To simplify the calculation process, a unit structure of 80 × 80 × 80 µm³ was created. The models of both materials are depicted in Fig. 5a. Considering the varied stress scenarios in practical material applications, stress levels ranging from 0.017 MPa to 11.3 MPa were simulated for the porous material. Figure 5b illustrates that as the applied stress increases, the average stress of the porous material exceeds that of the solid bulk material, indicating that the ultra-high porosity of the porous material amplifies the applied stress. Specifically, under stress of 0.017 MPa, the average stress distribution of the porous material is ~0.02 MPa, compared to 0.003 MPa for the solid bulk material. Under lower stress conditions, the stress distribution is more uniform in both porous and bulk materials, with the average stress in the former exceeding that in the latter. Under a stress of 11.3 MPa, the average internal stress of the bulk material is ~2.10 MPa, while the porous material exhibits an average stress of 13.35 MPa, ~6.4 times higher. Moreover, numerous regions within the porous material experience a maximum stress value of 15 MPa. Therefore, the in-situ porous design strategy employed in this study enables more effective absorption and transfer of mechanical energy to the piezoelectric components within the porous materials, resulting in an outstanding power generation effect.

a Model of porous composite of TMCM-CdCl3/TPU and TPU bulk material. b Results of COMSOL finite element simulation of Von Mises stress for porous material and block material with different stresses applied (0.017 MPa, 0.45 MPa, 1.3 MPa, 11.3 MPa).

Taking advantage of the superior ultrasonic absorption properties of porous materials (Fig. 6a and b), the porous piezoelectric composite materials developed in this study find application in underwater ultrasonic detection, as depicted in Fig. 6. Multiple porous composite piezoelectric materials form a sensing system capable of receiving ultrasonic waves across various areas of the water body. These waves are then converted into electrical signals for transmission to a signal collection tower, enabling ultrasonic detection across different water environments. The porous piezoelectric material is positioned within a water tank, with the ultrasonic source located in the tank’s center, as depicted in Supplementary Fig. 7. Due to varying distances from the ultrasonic emission source, the electrical signals generated by the porous piezoelectric material differ in magnitude across the left, middle, and right water regions, as depicted in the Fig. 6c, d, and e. Positioned on the left and right water regions, the porous piezoelectric material consistently outputs voltage signals of approximately 3 V, derived from the absorption of ultrasonic waves. However, when positioned closer to the ultrasonic vibration source in the center of the tank, the voltage generated significantly increases to around 5 V. Upon relocation to the right region, the electrical signal attenuates to approximately 3 V with fluctuations. This fluctuation may be attributed to water movement within the tank, leading to variations in ultrasonic transmission and subsequent signal attenuation. Analysis of the electrical signals across the three water regions facilitates comprehensive ultrasonic detection of the entire water area.

a, b The model diagram and the voltage diagram of ultrasonic detection of TMCM-CdCl3/TPU composite film and TMCM-CdCl3/TPU porous composite, respectively. c The schematic illustration of the self-powered sensor network system for underwater ultrasonic wave detection in different regions. d–f The voltage diagram of TMCM-CdCl3/TPU porous composite in the left, middle, and right regions of the water tank respectively.

This work successfully designs and fabricates a flexible piezoelectric material with ultra-high output power by leveraging the excellent organic compatibility of molecular ferroelectric materials and the unique properties of porous materials, including flexibility, stress transfer, and stress amplification. Experimental data reveal a continuous and uniform phase distribution of TMCM-CdCl3 and TPU in porous materials, particularly when the content reaches 50%. Molecular dynamics calculations indicate strong intermolecular forces between TMCM-CdCl3 and TPU, affirming their good compatibility. COMSOL finite element simulation further confirms that the three-dimensional interconnected porous skeleton structure of TPU facilitates stress transfer and amplification, thereby enhancing piezoelectric properties. The fabricated composite material, incorporated into an energy-harvesting device, demonstrates remarkable output voltage (103 V), current (42 μA), and power density (636.9 µW cm−2) under periodic external stimulation. This achievement, surpassing the performance of PVDF flexible piezoelectric membranes by 2000 times, represents a new benchmark in composite materials based on TMCM-CdCl3. The insights gained from this work contribute to the future design of flexible molecular ferroelectric composites with superior energy harvesting properties.

Thermoplastic polyurethane purchased (TPU) from Ningbo Heju New Material Technology Co., LTD. All reagents were purchased from commercial suppliers and used without further purification.

First, equal amounts of trimethylamine (30% water) and dichloromethane were reacted in acetonitrile at room temperature for 24 h to synthesize (chloromethyl) trimethyl ammonium chloride36. Then, 50 mmol of (Chloromethyl)trimethylammonium chloride and 50 mmol of Cadmium chloride were dissolved in deionized water. The solution was then slowly evaporated to obtain the single crystal TMCM-CdCl3.

The porous composite piezoelectric materials were prepared by freeze-drying method. Firstly, a precursor solution was prepared by dissolving polyurethane in a dioxane solution by heat, followed by the addition of ionized water. Secondly, a previously synthesized TMCM-CdCl3 crystal is introduced as a voltage source and thoroughly stirred to ensure a homogeneous distribution. The third step involved pre-freezing treatment, during which the cooling process caused dioxane to solidify first and separate from the polyurethane and water phase, followed by the Solidification of deionized water. This is the key to the formation of highly ordered porosity. Finally, freeze-drying was conducted, leading to the sublimation of ice and dioxane, ultimately forming an interconnected pore structure, Then, the porous composite piezoelectric materials were polarized for 12 h at a field intensity of 3 kV/mm.

A series of piezoelectric energy harvesting devices with sandwich structures were prepared, the different proportions circular porous piezoelectric composite material with a diameter of 1.5 cm and a thickness of 0.5 cm as the piezoelectric active material. The upper and lower interfaces are covered with copper sheets or conductive tape as electrodes, and finally, the devices are encapsulated in commercial PET films.

The COMSOL solid mechanics module was used to describe the skeleton cell stress. The cell size was 80 × 80 × 80 µm3 and the porous skeleton was inserted inside. The pressure on one end of the skeleton cell is 0.017 MPa, 0.45 MPa, 1.3 MPa, and 11.3 MPa, and the other end is fixed. The remaining surfaces are free boundaries. The same method was used to calculate the stress of the solid block material, whose cell size was also 80 × 80 × 80 µm3. The pressure of one end of the skeleton cell was 0.017 MPa, 0.45 MPa, 1.3 MPa, and 11.3 MPa, and the other end was fixed. The remaining surfaces are free boundaries.

X-ray diffraction (XRD) patterns of porous piezoelectric composites with different proportions and pure TMCM-CdCl3 crystals were recorded by Bruker D8 Advance Cu-K radiation diffractometer (XRD, Bruker, Germany). The morphology of the porous composite piezoelectric materials was observed by field emission scanning electron microscope (FE-SEM, America). The porous piezoelectric composite was polarized by a high-voltage polarization device (MPD 10 kV). In the energy harvesting test, a signal collector (9004) was used to monitor the open-circuit voltage and short-circuit current between the two electrodes on the sample under repeated compression induced by a linear motor (MS-1000).

The data supporting the findings of this study are reported in the main text or the Supplementary Information. Source data are provided with this paper and in the figshare database with the link: https://doi.org/10.6084/m9.figshare.26353174.

Ye, Y.-z et al. Design of piezoelectric organic cage salts for energy harvesting. Chem 10, 1–14 (2024).

Article Google Scholar

Bai, Y., Jantunen, H. & Juuti, J. Energy harvesting research: the road from single source to multisource. Adv. Mater. 30, 1707271 (2018).

Article Google Scholar

Gao, X. et al. Giant piezoelectric coefficients in relaxor piezoelectric ceramic PNN‐PZT for vibration energy harvesting. Adv. Funct. Mater. 28, 1706895 (2018).

Article ADS Google Scholar

Wang, Z. L. & Song, J. Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 312, 242–246 (2006).

Article ADS CAS PubMed Google Scholar

Yang, Z., Zhou, S., Zu, J. & Inman, D. High-performance piezoelectric energy harvesters and their applications. Joule 2, 642–697 (2018).

Article CAS Google Scholar

Fan, F. R., Tang, W. & Wang, Z. L. Flexible nanogenerators for energy harvesting and self‐powered electronics. Adv. Mater. 28, 4283–4305 (2016).

Article CAS PubMed Google Scholar

Zhou, Q. et al. Piezoelectric single crystal ultrasonic transducers for biomedical applications. Prog. Mater. Sci. 66, 87–111 (2014).

Article PubMed Central CAS PubMed Google Scholar

Yousry, Y. M. et al. Shear mode ultrasonic transducers from flexible piezoelectric PLLA fibers for structural health monitoring. Adv. Funct. Mater. 33, 2213582 (2023).

Article CAS Google Scholar

Lu, H. et al. 3D Printing and processing of miniaturized transducers with near-pristine piezoelectric ceramics for localized cavitation. Nat. Commun. 14, 2418 (2023).

Article ADS PubMed Central CAS PubMed Google Scholar

Zhang, L. et al. An emerging era: conformable ultrasound electronics. Adv. Mater. 36, 2307664 (2024).

Article CAS Google Scholar

Xie, M. et al. Flexible and active self-powered pressure, shear sensors based on freeze casting ceramic–polymer composites. Energy Environ. Sci. 11, 2919–2927 (2018).

Article PubMed Central CAS PubMed Google Scholar

Schmidt, G. C. et al. Paper‐embedded roll‐to‐roll mass printed piezoelectric transducers. Adv. Mater. 33, 2006437 (2021).

Article CAS Google Scholar

Min, S. et al. Clinical validation of a wearable piezoelectric blood‐pressure sensor for continuous health monitoring. Adv. Mater. 35, 2301627 (2023).

Article CAS Google Scholar

Wang, Y. et al. Piezo-catalysis for nondestructive tooth whitening. Nat. Commun. 11, 1328 (2020).

Article ADS PubMed Central CAS PubMed Google Scholar

Liu, J. et al. Piezocatalytic techniques in environmental remediation. Angew. Chem. Int. Ed. 62, e202213927 (2022).

Article Google Scholar

Tu, S. et al. Piezocatalysis and piezo‐photocatalysis: catalysts classification and modification strategy, reaction mechanism, and practical application. Adv. Funct. Mater. 30, 2005158 (2020).

Article CAS Google Scholar

Curie, J. & Curie, P. Développement par compression de l'électricité polaire dans les cristaux hémièdres à faces inclinées. Bull. Mineral. 3, 90–93 (1880).

Google Scholar

Acosta, M. et al. BaTiO3-based piezoelectrics: fundamentals, current status, and perspectives. Appl. Phys. Rev. 4, 041305 (2017).

Article ADS Google Scholar

Jaffe, B. et al. Piezoelectric properties of lead zirconate-lead titanate solid-solution ceramics. J. Appl. Phys. 25, 809–810 (1954).

Article ADS CAS Google Scholar

Yan, Y. et al. Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO3 material. Nat. Commun. 7, 13089 (2016).

Article ADS PubMed Central CAS PubMed Google Scholar

Yan, Y. et al. Giant energy density in [001]-textured Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics. Appl. Phys. Lett. 102, 042903 (2013).

Article ADS Google Scholar

Yang, S. et al. Full matrix electromechanical properties of textured Pb(In1/2Nb1/2)O3-Pb(Sc1/2Nb1/2)O3-PbTiO3 ceramic. J. Appl. Phys. 131, 124104 (2022).

Article ADS CAS Google Scholar

Li, J. et al. Lead zirconate titanate ceramics with aligned crystallite grains. Science 380, 87–93 (2023).

Article ADS CAS PubMed Google Scholar

Zhang, G. et al. Flexible three-dimensional interconnected piezoelectric ceramic foam-based composites for highly efficient concurrent mechanical and thermal energy harvesting. Energy Environ. Sci. 11, 2046–2056 (2018).

Article Google Scholar

Tang, T. et al. Stretchable polymer composites with ultrahigh piezoelectric performance. Natl Sci. Rev. 10, nwad177 (2023).

Article PubMed Central CAS PubMed Google Scholar

Xu, Q. et al. Construction of flexible piezoceramic array with ultrahigh piezoelectricity via a hierarchical design strategy. Adv. Funct. Mater. 33, 2304402 (2023).

Article CAS Google Scholar

Yan, M. et al. Enhanced energy harvesting performance in lead-free multi-layer piezoelectric composites with a highly aligned pore structure. Nano Energy 106, 108096 (2023).

Article CAS Google Scholar

Shi, C. et al. Large piezoelectric response in hybrid rare-earth double perovskite relaxor ferroelectrics. J. Am. Chem. Soc. 142, 9634–9641 (2020).

Article CAS PubMed Google Scholar

Li, K. et al. Elastic properties related energy conversions of coordination polymers and metal–organic frameworks. Coord. Chem. Rev. 470, 214692 (2022).

Article CAS Google Scholar

Li, W. et al. Chemically diverse and multifunctional hybrid organic–inorganic perovskites. Nat. Rev. Mater. 2, 16099 (2017).

Article ADS Google Scholar

Zhang, F. et al. Enhanced charge transport in 2D perovskites via fluorination of organic cation. J. Am. Chem. Soc. 141, 5972–5979 (2019).

Article CAS PubMed Google Scholar

Liu, H. Y. et al. Molecular design principles for ferroelectrics: ferroelectrochemistry. J. Am. Chem. Soc. 142, 15205–15218 (2020).

Article CAS PubMed Google Scholar

Fu, D. W. et al. Diisopropylammonium bromide is a high-temperature molecular ferroelectric crystal. Science 339, 425–428 (2013).

Article ADS CAS PubMed Google Scholar

Guo, T. M. et al. Mechanical and acoustic properties of a hybrid organic–inorganic perovskite, TMCM-CdCl3, with large piezoelectricity. APL Mater. 8, 101106 (2020).

Article ADS CAS Google Scholar

Gong, Y. J. et al. High power density energy harvesting and human motion monitoring with [trimethylchloromethyl ammonium][CdCl3]/polymer composite. Matter 6, 2066–2080 (2023).

Article CAS Google Scholar

You, Y. M. et al. An organic-inorganic perovskite ferroelectric with large piezoelectric response. Science 357, 306–309 (2017).

Article ADS CAS PubMed Google Scholar

Lv, H. P. et al. Inch-size molecular ferroelectric crystal with a large electromechanical coupling factor on par with barium titanate. J. Am. Chem. Soc. 144, 22325–22331 (2022).

Article CAS PubMed Google Scholar

Song, X. J. et al. The first demonstration of strain‐controlled periodic ferroelectric domains with superior piezoelectric response in molecular materials. Adv. Mater. 35, 2211584 (2023).

Article CAS Google Scholar

Liao, W. Q. et al. A molecular perovskite solid solution with piezoelectricity stronger than lead zirconate titanate. Science 363, 1206–1210 (2019).

Article ADS CAS PubMed Google Scholar

Wang, B. et al. Achievement of a giant piezoelectric coefficient and piezoelectric voltage coefficient through plastic molecular-based ferroelectric materials. Matter 5, 1296–1304 (2022).

Article CAS Google Scholar

Zhang, Y. et al. Piezoelectric energy harvesting based on multiaxial ferroelectrics by precise molecular design. Matter 2, 697–710 (2020).

Article Google Scholar

Ding, R. et al. Flexible piezoelectric nanocomposite generators based on formamidinium lead halide perovskite nanoparticles. Adv. Funct. Mater. 26, 7708–7716 (2016).

Article CAS Google Scholar

Khan, A. A. et al. Superior transverse piezoelectricity in organic-inorganic hybrid perovskite nanorods for mechanical energy harvesting. Nano Energy 86, 106039 (2021).

Article CAS Google Scholar

Chen, P. et al. Wireless deep brain stimulation by ultrasound-responsive molecular piezoelectric nanogenerators. ACS Nano 17, 25625–25637 (2023).

Article CAS PubMed Google Scholar

Guo, T. M. et al. A new hybrid lead‐free metal halide piezoelectric for energy harvesting and human motion sensing. Small 18, 2103829 (2021).

Article Google Scholar

Chattopadhyay, D. K. et al. Thermal stability and flame retardancy of polyurethanes. Prog. Polym. Sci. 34, 1068–1133 (2009).

Article CAS Google Scholar

Kim, S. et al. Circular reprocessing of thermoset polyurethane foams. Adv. Mater. 35, 2305387 (2023).

Article ADS CAS Google Scholar

Kemona, A. et al. Polyurethane recycling and disposal: methods and prospects. Polym 12, 1752 (2020).

Article CAS Google Scholar

Zhang, S. et al. 3D printing thermoplastic polyurethane hierarchical cellular foam with outstanding energy absorption capability. Addit. Manuf. 76, 103770 (2023).

CAS Google Scholar

Zhu, G. et al. Highly-stretchable porous thermoplastic polyurethane/carbon nanotubes composites as a multimodal sensor. Carbon 195, 364–371 (2022).

Article CAS Google Scholar

Zhang, X. et al. The preparation of high performance multifunctional porous sponge through a biomimic coating strategy based on polyurethane dendritic colloids. Chem. Eng. J. 438, 135659 (2022).

Article ADS CAS Google Scholar

Li, W. et al. Molecular ferroelectric‐based flexible sensors exhibiting supersensitivity and multimodal capability for detection. Adv. Mater. 33, 2104107 (2021).

Article CAS Google Scholar

Yang, B. et al. Flexible PVDF based piezoelectric nanogenerators. Nano Energy 78, 105251 (2020).

Article Google Scholar

Thompson, A. P. et al. LAMMPS—a flexible simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales. Comp. Phys. Comm. 271, 108171 (2022).

Article CAS Google Scholar

Rappe, A. K. et al. UFF, a full periodic table force field for molecular mechanics and molecular dynamics simulations. J. Am. Chem. Soc. 114, 10024–10035 (1992).

Article CAS Google Scholar

Chen, H. et al. Piezoelectric nanogenerator based on in situ growth all-inorganic CsPbBr3 perovskite nanocrystals in PVDF fibers with long-term stability. Adv. Funct. Mater. 31, 2011073 (2021).

Article CAS Google Scholar

Deswal, S. et al. Flexible composite energy harvesters from ferroelectric A2MX4-type hybrid halogenometallates. Chem. Mater. 31, 4545–4552 (2019).

Article CAS Google Scholar

Ding, R. et al. High-performance piezoelectric nanogenerators composed of formamidinium lead halide perovskite nanoparticles and poly(vinylidene fluoride). Nano Energy 37, 126–135 (2017).

Article CAS Google Scholar

Deswal, S. et al. Neutral 1D perovskite-type ABX3 ferroelectrics with high mechanical energy harvesting performance. Chem. Mater. 32, 8333–8341 (2020).

Article CAS Google Scholar

Ippili, S. et al. Unveiling predominant air-stable organotin bromide perovskite toward mechanical energy harvesting. ACS Appl. Mater. Interfaces 12, 16469–16480 (2020).

Article CAS PubMed Google Scholar

Liu, H. et al. Enhanced performance of piezoelectric composite nanogenerator based on gradient porous PZT ceramic structure for energy harvesting. J. Mater. Chem. A 8, 19631–19640 (2020).

Article CAS Google Scholar

Weaire, D. et al. A counter-example to Kelvin’s conjecture on minimal surfaces. Philos. Mag. Lett. 69, 107–110 (1994).

Article ADS MathSciNet CAS Google Scholar

Download references

This work was financially supported by National Natural Science Foundation of China (52303256 (H.-F. L.), grant 21991141 (D.-W, F.), 52173020 (Y.-J. N.), 22375182 (Y. Z.) and 22371258 (D.-W, F.)), Natural Science Foundation of Zhejiang Province (LQ23B040004 (H.-F. L.) and LZ24B010001 (Y. Z.)) and Jinhua Industrial Major Project (2022-1-043) (H.-F. L.).

These authors contributed equally: Jia-Qi Luo, Hai-Feng Lu, Yi-Jing Nie.

Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, PR China

Jia-Qi Luo, Hai-Feng Lu, Chang-Feng Wang, Zhi-Xu Zhang, Da-Wei Fu & Yi Zhang

Institute of Polymer Materials, School of Materials Science and Engineering, Jiangsu University, Zhenjiang, PR China

Yi-Jing Nie & Yu-Hang Zhou

Ordered Matter Science Research Center, Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, PR China

Da-Wei Fu

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

Conceptualization: H.-F.L., D.-W.F., and Y.Z. Investigation: C.-F.W., Z.-X.Z. Molecular dynamics simulation: Y.-J.N., Y.-H.Z. Visualization: J.-Q.L., H.-F.L. Funding acquisition, Y.-J.N., H.-F.L., D.-W.F. and Y.Z. Writing—Original Draft. J.-Q.L. Writing—Review & Editing: All authors

Correspondence to Hai-Feng Lu, Da-Wei Fu or Yi Zhang.

The authors declare no competing interests.

Nature Communications thanks the anonymous reviewer(s) for their contribution to the peer review of this work. A peer review file is available.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

Reprints and permissions

Luo, JQ., Lu, HF., Nie, YJ. et al. Porous flexible molecular-based piezoelectric composite achieves milliwatt output power density. Nat Commun 15, 8636 (2024). https://doi.org/10.1038/s41467-024-53031-9

Download citation

Received: 02 April 2024

Accepted: 26 September 2024

Published: 05 October 2024

DOI: https://doi.org/10.1038/s41467-024-53031-9

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative