Piezoelectric-Triboelectric Hybrid Nanogenerator for Energy Harvesting and Self-Powered Sensing Applications

Abstract

In the contemporary era, self-powered sensors have gained significant attention, particularly in the domains of wearable devices, flexible electronics, healthcare monitoring devices, and the Internet of Things (IoT). Among the most promising technologies for mechanical energy harvesting are piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), both of which convert ambient mechanical energy into electrical energy. However, the electrical output from either PENGs or TENGs alone is often insufficient to meet the power requirements of electronic devices. To address this limitation, the integration of piezoelectric and triboelectric effects into a single system has led to the emergence of piezoelectric-triboelectric hybrid nanogenerators (PT-HNGs). These hybrid systems represent a new class of energy harvesting devices capable of significantly enhancing energy conversion efficiency and output performance. This review provides a comprehensive overview of recent progress in developing PT-HNGs, focusing on their underlying mechanisms, structural designs, coupling effects, performance optimization strategies, and diverse application potentials. It highlights the hybrid system's unique synergy and real-world applicability, aiming to fill a critical gap in the literature. In addition, the review discusses the existing challenges, future directions, and prospects for the commercialization of PT-HNG technology.

Keywords: energy harvester; hybrid nanogenerators; piezoelectricity; self‐powered sensing; triboelectricity.

Figure 1

Potential applications of piezoelectric‐triboelectric hybrid nanogenerators (PT‐HNGs), with the central depiction of mechanical energy sources utilized for energy harvesting, surrounded by various applications, particularly in healthcare monitoring, self‐powered sensing, and wearable electronics.

Figure 2

Mechanism of charge transfer in TENGs. a) Separated materials b) contact of materials and c) triboelectric series. Reprinted (Adapted) with permission.^{[ 46 ]} Copyright 2024, American Chemical Society. d) Work function of Kapton and PET, and e) Charge density of Kapton and PET. Reprinted (Adapted) with permission.^{[ 45 ]} Copyright 2022, American Chemical Society.

Figure 3

Working principles of a) a PENG and b) a TENG. Reprinted (Adapted) with permission.^{[ 47 ]} Copyright 2020, Elsevier.

Figure 4

Coupling of Piezoelectric and Triboelectric Effects. a) PVDF/PDMS‐based PT‐HNG as a stable linear generator. Reprinted (adapted) with permission.^{[ 59 ]} Copyright 2019, Elsevier. b) poled PVDF‐TrFE, PTFE, and Al layers as PT‐HNG for high performance. Reprinted (adapted) with permission.^{[ 60 ]} Copyright 2019, Elsevier. c) CsPbI₃ reinforced in PVDF as PT‐HNG for humidity sensor. Reprinted (adapted) with permission.^{[ 62 ]} Copyright 2024, American Chemical Society.

Figure 5

PT‐HNGs systems. Working mechanism of a) two‐electrode module and b) three‐electrode module.

Figure 6

Schematic illustration of two and three‐electrode PT‐HNG based on a) PDMS/ZnO NFs/3D Gr/Ni foam. Reprinted (Adapted) with permission.^{[ 75 ]} Copyright 2018, American Chemical Society. b) BCZT/PVDF‐HFP composite nanofibers (BP‐based NFs). Reproduced (Adapted) with permission.^{[ 76 ]} Copyright 2019, The Royal Society of Chemistry. c) BaTiO₃‐Nanorods/Chitosan, Reprinted (Adapted) with permission.^{[ 71 ]} Copyright 2021, Elsevier. d) Stretchable, Breathable, and Stable Lead‐Free Perovskite/Polymer‐based PT‐HNG. Reprinted (Adapted) with permission.^{[ 77 ]} Copyright 2022, John Wiley and Sons. e) Schematic structure and electro‐circuit diagram of a ZnO nanorod/PVDF‐PTFE based PT‐HNG. Reprinted (Adapted) with permission.^{[ 78 ]} Copyright 2018, Elsevier. f) Diagram of an arc‐shaped PVDF‐PTFE‐based PT‐HNG. Reproduced (Adapted) with permission.^{[ 79 ]} Copyright 2015, Springer Nature. g) 2D schematic using three for improving ocean wave impact energy harvesting. Reprinted (Adapted) with permission.^{[ 15 ]} Copyright 2020, Elsevier. h) Schematic diagram of a PT‐HNG with point contact between two electrodes. Reprinted (Adapted) with permission.^{[ 22 ]} Copyright 2020, Elsevier.

Figure 7

Influence of materials on enhancing the performance of PT‐HNGs. a) Schematic of a PVDF:PZT‐N PT‐HNGs device, showing an output voltage increase from 20.15 V to 40.2 V with PT‐HNG integration. Reprinted (Adapted) with permission.^{[ 123 ]} Copyright 2024, American Chemical Society. b) Hybrid ZnO‐CsPbBr₃/PVDF‐HFP PT‐HNGs design, with HRTEM of CsPbBr₃ nanoparticles and voltage variation under dark and visible light. Reprinted (Adapted) with permission.^{[ 124 ]} Copyright 2024, American Chemical Society. c) PVDF–PDMS composite film under stretching, SEM morphology, and comparisons of VOC and power density for PENG, TENG, and PT‐NG. Reprinted (Adapted) with permission.^{[ 66 ]} Copyright 2024, American Chemical Society. d) Hybrid MWCNTs/ZnO/PDMS PT‐HNG device, showing high flexibility and superior VOC output. Reprinted (Adapted) with permission.^{[ 82 ]} Copyright 2018, American Chemical Society. e) 3D schematic and photograph of PT‐HNG, with TENG and EMG electrodes, illustrating voltage output and power density performance across modes. Reprinted (Adapted) with permission.^{[ 125 ]} Copyright 2023, Elsevier.

Figure 8

Influence of surface modification on enhancing the performance of PT‐HNGs a) Digital photo and schematic of the device, illustrating its flexible composite film and micro‐roughness created via soft‐lithographic sandpaper method. The comparison of VOC responses highlights enhanced output due to increased roughness. Reprinted (Adapted) with permission.^{[ 135 ]} Copyright2020, Elsevier. b) The working mechanism of the triboelectric state sensing part (TSSP) with SEM images of the forested surface shows transient voltage signals influenced by surface treatments. Reprinted (Adapted) with permission.^{[ 136 ]} Copyright 2023, Elsevier. c) Schematic of device fabrication and assembly, featuring O2 plasma‐treated interdigitated microelectrodes, core@multishell nanowires in a PDMS layer, and enhanced PT‐HNGs performance through architectural optimization. Reprinted (Adapted) with permission.^{[ 137 ]} Copyright 2022, Elsevier.

Figure 9

Influence of device design and electronic circuit aid on enhancing the performance of PT‐HNGs a) Schematic of PT‐HNG, showing exploded views of components, 3D excitation‐PENG structure, and PVDF film operation under rotational excitation, with a performance comparison of PENG, TENG, and PE‐TENG outputs. Reprinted (Adapted) with permission.^{[ 139 ]} Copyright 2023, Elsevier. b) Structural composition of PR‐PT‐HNG, comparing output power of TENG and PENG to the hybrid PR‐PT‐HNG, which powers over 1400 LEDs. Reprinted (Adapted) with permission.^{[ 140 ]} Copyright 2024, Elsevier. c) Structural composition of PR‐PT‐HNG, comparing output power of TENG and PENG to the hybrid PR‐PT‐HNG. Reprinted (Adapted) with permission.^{[ 141 ]} Copyright 2023, Elsevier.

Figure 10

TENG enhances PENG for enhanced PT‐HNGs output a) Schematic of the micro‐pyramidal BaTiO₃/PDMS TENG, BaTiO₃ crystal structure before and after pressure, and V_OC comparison of different PDMS‐based TENGs. Real‐time V_OC responses, power density vs. load resistance, circuit diagram, and LED demonstration. Reprinted (Adapted) with permission.^{[ 143 ]} Copyright 2024, Elsevier. b) Fabrication and surface modification of NFs, PT‐HNG energy conversion mechanism, charge transfer via graphene flakes, textile sensor testing, and SEM images of roughened NFs. Reprinted (Adapted) with permission.^{[ 144 ]} Copyright 2023, American Chemical Society. c) FESEM and HRTEM images of CsPbI₃, with the deconvoluted X‐ray diffraction (XRD) profile of PVI 5, confirm the high crystallinity. Schematic diagrams depict the working mechanism of the device and its electrical performance, including V_OC, which is shown for all devices, with TENG power output in different modes. Additionally, including a digital image of the humidity sensing circuit setup, schematic design of the self‐powered humidity sensor in triboelectric contact‐separation mode (HTECS), and the glowing LEDs in the ‘TFL’ pattern by HTECS Reprinted (Adapted) with permission.^{[ 62 ]} Copyright 2024, American Chemical Society.

Figure 11

PENG enhances TENG for enhanced PT‐HNGs output. a) Schematic of the PT‐HNG, SEM images of PLGA nanofibers and PVA/Gy/PVA film, and output comparisons under different coupling conditions. In vivo analysis includes implantation images, toxicity assessment, and electrode degradation over 14 days. Wafer‐scale film preparation with SEM/EDS mapping is shown. Reprinted (Adapted) with permission.^{[ 145 ]} Copyright 2024, Elsevier. b) PT‐HNG structure with SnSe₂‐MXene‐embedded PDMS, XRD/SEM characterization, and enhanced output in vertical contact‐separation mode. Power density comparison, capacitor charging, and application in a speed detection system are demonstrated. Reprinted (Adapted) with permission.^{[ 146 ]} Copyright 2024, Elsevier.

Figure 12

PT‐HNGs for energy harvesting applications, a) Working mechanism in a press‐and‐release cycle, and output performances. Reproduced (Adapted) with permission.^{[ 79 ]} Copyright 2015, Springer Nature. b) Schematic and working principle of a hybrid piezoelectric‐triboelectric nanogenerator (H‐P/TENG) for rotary energy harvesting. The inset shows the layered structure of the hybrid device including the fabrication process, working mechanism under deformation, and synchronous voltage outputs from the TENG and PENG components. Reprinted (adapted) with permission.^{[ 60 ]} Copyright 2019, Elsevier. c) PT‐HNG along with the electrical connections. Reprinted (Adapted) with permission.^{[ 78 ]} Copyright 2018, Elsevier. d) 3D expanded views of the PENG (i) and TENG (ii) components, with real photos (iii, iv); (v) assembly and (vi) real photo of the full PT‐HNG attached on a substrate. Reprinted (Adapted) with permission.^{[ 160 ]} Copyright 2021, Elsevier. e) Schematic diagram of flexible PT‐HNG via Polydimethylsiloxane‐Encapsulated Nanoflower‐like ZnO Composite Films. Reprinted (Adapted) with permission.^{[ 82 ]} Copyright 2018, American Chemical Society. f) Diagram and a digital photograph of PT‐HNG embedded in a shoe insole, rectified short‐circuit currents for various human motions. Reprinted (Adapted) with permission.^{[ 86 ]} Copyright 2020, Elsevier. g) Butterfly wing structure composed of four arc‐shaped HNG with an irregular surface morphology (a1, a2, a3, and a4); and output current density of single (a1) and multiunit HNGs connected in parallel at a constant acceleration. Reprinted (Adapted) with permission.^{[ 161 ]} Copyright 2018, Elsevier. h) Structural configuration of the PT‐HNG. Key components are listed as: 1. triboelectric patch, 2. proof mass, 3. linear spring, 4. truss mechanism, 5. piezoelectric plate and 6. piezoelectric plate holders. Reprinted (Adapted) with permission.^{[ 163 ]} Copyright 2018, Elsevier. i) The Components of the device include Biomechanical energy harvesting from human activities, smart home stair sensor, and emergency e‐mail alert applications. Reprinted (Adapted) with permission.^{[ 164 ]} Copyright 2024, John Wiley and Sons. j) Schematic diagram representing the reactions of MCHCFS in h) absence and i) presence of external force applied while human walking. Reprinted (Adapted) with permission.^{[ 165 ]} Copyright 2023, John Wiley and Sons. k) The clip‐like PT‐HNG device when placed on the pedal attached to the musical piano and the car's accelerator pedal with the working cycle. Reprinted (adapted) with permission.^{[ 166 ]} Copyright 2024, Elsevier.

Figure 13

Human motion monitoring using wearable hybrid sensors. a) (i) PTSS attached to the skin without any skin irritation. (ii‐v) Wrist bending and twisting motion and their corresponding voltage response with a zoomed view of each cycle. (vi, vii). PTSS signals are out of the water and inside the water. Reprinted (Adapted) with permission.^{[ 167 ]} Copyright 2022, MDPI. b) Smart hybrid sock for detecting disability in regular walking. (i) Comparative gait analysis for regular walking and person with walking disabilities‐ loss of stride and freezing of gait (FOG). (ii) Typical walking cycle consisting of^{[ 1 ]} heel contact,^{[ 2 ]} forefoot/toe contact,^{[ 3 ]} heel leave, and^{[ 4 ]} forefoot/toe leave and its corresponding voltage output signal. Reprinted (Adapted) with permission.^{[ 171 ]} Copyright 2019, American Chemical Society. c) (i) Human posture monitoring using PT‐HNG. (ii‐vi) The output dependence on the range of physical movements. Reprinted (Adapted) with permission.^{[ 168 ]} Copyright 2019, Elsevier. d) Remote emergency fall alert microsystem. (i) Schematic of the sensing setup with PT‐HNG and micro‐cantilever. PT‐HNG served as a force detector in case of a sudden fall. (ii) PT‐HNG is connected to a micro‐cantilever, which acts as a switch for sending an emergency signal in case of a sudden fall. (iii) The emergency message was sent to a designated remote terminal. (iv) The force of the impact of a sudden fall generates an electrical pulse through the PT‐HNG. If this force generates an electrical output beyond a preset voltage value, a signal will be triggered to pull the micro‐cantilever downward the bottom electrode to activatethe computer program to send an emergency message. (v) The sensor can detect various human motions at the switch‐off stage. Reprinted (Adapted) with permission.^{[ 172 ]} Copyright 2018, Elsevier.

Figure 14

a) FPT‐HNG for self‐powered weather monitoring i) sunny day, ii) rainy day, and iii) both sunny and rainy day. Reprinted (adapted) with permission.^{[ 186 ]} Copyright 2021, John Wiley and Sons. b) PT‐HNG for respiration and artery pulse monitoring. (i) Respiration signal for different states of breathing. (ii) Zoomed‐in view of a breathing cycle. (iii) Artery pulse signal (iv) Zoomed‐in view of an artery pulse cycle. Reprinted (Adapted) with permission.^{[ 169 ]} Copyright 2017, Elsevier. c) Continuous blood pulse wave sensing with PT‐HNG. (i) Schematic diagram of HPTS attached to the wrist. The HPTS was positioned over skin and muscle but was sensitive enough to detect the pulse motion, harnessing the slight movement of the radial artery. (ii) Continuous pulse wave generation for a healthy man. (iii) Zoomed‐in view of each pulse cycle. (iv,v) Comparative analysis of P wave, conducted between a healthy man and a woman. Reprinted (Adapted) with permission.^{[ 168 ]} Copyright 2019, Elsevier.

Figure 15

Illustration of challenges and prospects for PT‐HNGs development.