Pyroelectric energy harvesting systems have recently received substantial attention for their potential applications as power generators. In particular, the pyroelectric effect, which converts ...thermal energy into electrical energy, has been utilized as an infrared (IR) sensor, but upcoming sensor technology that requires a miniscule amount of power is able to utilize pyroelectric nanogenerators (PyNGs) as a power source. Herein, an overview of the progress in the development of PyNGs for an energy harvesting system that uses environmental or artificial energies such as the sun, body heat, and heaters, is provided. It begins with a brief introduction of the pyroelectric effect, and various polymer and ceramic materials based PyNGs are reviewed in detail. Various approaches for developing polymer‐based PyNGs and various ceramic materials–based PyNGs are summarized in particular. Finally, challenges and perspectives regarding the PyNGs are described.
Converting thermal energy into electrical energy using pyroelectric nanogenerators is a promising technology to utilize abundant thermal energy. Herein, a variety of polymers and ceramic‐based flexible, stretchable, and hybrid pyroelectric nanogenerators are reviewed. The working mechanism of the pyroelectric nanogenerators is provided, and a perspective for high performance pyroelectric nanogenerators is presented.
Recently, sustainable green energy harvesting systems have been receiving great attention for their potential use in self‐powered smart wireless sensor network (WSN) systems. In particular, though ...the developed WSN systems are able to advance public good, very high and long‐term budgets will be required in order to use them to supply electrical energy through temporary batteries or connecting power cables. This report summarizes recent significant progress in the development of hybrid nanogenerators for a sustainable energy harvesting system that use natural and artificial energies such as solar, wind, wave, heat, machine vibration, and automobile noise. It starts with a brief introduction of energy harvesting systems, and then summarizes the different hybrid energy harvesting systems: integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. In terms of the reported hybrid nanogenerators, a systematic summary of their structures, working mechanisms, and output performances is provided. Specifically, electromagnetic induction, triboelectric, piezoelectric, photovoltaic, thermoelectric, and pyroelectric effects are reviewed on the basis of the individual and hybrid power performances of hybrid nanogenerators and their practical applications with various device designs. Finally, the perspectives on and challenges in developing high performance and sustainable hybrid nanogenerator systems are presented.
Recent progress in the development of sustainable hybrid nanogenerators is summarized, by focusing on the integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. The working mechanism of the hybrid nanogenerators is provided, and challenges and perspectives for a high‐performance sustainable hybrid nanogenerator systems are presented.
Recent findings demonstrate that cellulose, a highly abundant, versatile, sustainable, and inexpensive material, can be used in the preparation of very stable and flexible electrochemical energy ...storage devices with high energy and power densities by using electrodes with high mass loadings, composed of conducting composites with high surface areas and thin layers of electroactive material, as well as cellulose‐based current collectors and functional separators. Close attention should, however, be paid to the properties of the cellulose (e.g., porosity, pore distribution, pore‐size distribution, and crystallinity). The manufacturing of cellulose‐based electrodes and all‐cellulose devices is also well‐suited for large‐scale production since it can be made using straightforward filtration‐based techniques or paper‐making approaches, as well as utilizing various printing techniques. Herein, the recent development and possibilities associated with the use of cellulose are discussed, regarding the manufacturing of electrochemical energy storage devices comprising electrodes with high energy and power densities and lightweight current collectors and functional separators.
The recent progress of cellulose, as an appealing natural material that can outperform traditional synthetic materials, for use in energy‐storage devices is described. Cellulose can bring benefits in the fabrication and properties of energy‐storage materials and devices, eventually enabling significant improvements in electrochemical performance, mechanical flexibility, cost competitiveness, and form factors, which are difficult to achieve with conventional power source technologies.
Graphene tribotronics is introduced for touch‐sensing applications such as electronic skins and touch screens. The devices are based on a coplanar coupling of triboelectrification and current ...transport in graphene transistors. The touch sensors are ultrasensitive, fast, and stable. Furthermore, they are transparent and flexible, and can spatially map touch stimuli such as movement of a ball, multi‐touch, etc.
Biomolecular piezoelectric materials are considered a strong candidate material for biomedical applications due to their robust piezoelectricity, biocompatibility, and low dielectric property. The ...electric field has been found to affect tissue development and regeneration, and the piezoelectric properties of biological materials in the human body are known to provide electric fields by pressure. Therefore, great attention has been paid to the understanding of piezoelectricity in biological tissues and its building blocks. The aim herein is to describe the principle of piezoelectricity in biological materials from the very basic building blocks (i.e., amino acids, peptides, proteins, etc.) to highly organized tissues (i.e., bones, skin, etc.). Research progress on the piezoelectricity within various biological materials is summarized, including amino acids, peptides, proteins, and tissues. The mechanisms and origin of piezoelectricity within various biological materials are also covered.
The piezoelectricity of the various elements constituting the human body has attracted intensive attention, due to the strong piezoelectricity, biocompatibility, low dielectric, and tissue regeneration effects. Research progress in the various biological piezoelectric materials from the basic building blocks to organized tissues are summarized. The mechanisms and origins of piezoelectricity are discussed, and challenges and perspectives for developing biological piezoelectric materials are presented.
Abstract
Self-powered implantable devices have the potential to extend device operation time inside the body and reduce the necessity for high-risk repeated surgery. Without the technological ...innovation of in vivo energy harvesters driven by biomechanical energy, energy harvesters are insufficient and inconvenient to power titanium-packaged implantable medical devices. Here, we report on a commercial coin battery-sized high-performance inertia-driven triboelectric nanogenerator (I-TENG) based on body motion and gravity. We demonstrate that the enclosed five-stacked I-TENG converts mechanical energy into electricity at 4.9 μW/cm
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(root-mean-square output). In a preclinical test, we show that the device successfully harvests energy using real-time output voltage data monitored via Bluetooth and demonstrate the ability to charge a lithium-ion battery. Furthermore, we successfully integrate a cardiac pacemaker with the I-TENG, and confirm the ventricle pacing and sensing operation mode of the self-rechargeable cardiac pacemaker system. This proof-of-concept device may lead to the development of new self-rechargeable implantable medical devices.
Recently, as applications based on triboelectricity have expanded, understanding the triboelectric charging behavior of various materials has become essential. This study investigates the ...triboelectric charging behaviors of various 2D layered materials, including MoS2, MoSe2, WS2, WSe2, graphene, and graphene oxide in a triboelectric series using the concept of a triboelectric nanogenerator, and confirms the position of 2D materials in the triboelectric series. It is also demonstrated that the results are obviously related to the effective work functions. The charging polarity indicates the similar behavior regardless of the synthetic method and film thickness ranging from a few hundred nanometers (for chemically exfoliated and restacked films) to a few nanometers (for chemical vapor deposited films). Further, the triboelectric charging characteristics could be successfully modified via chemical doping. This study provides new insights to utilize 2D materials in triboelectric devices, allowing thin and flexible device fabrication.
A triboelectric series of 2D layered materials is confirmed using the concept of a triboelectric nanogenerator. The position of 2D materials in the triboelectric series is obviously related to the output signal obtained from the triboelectric nanogenerator and the effective work function. These results provide new insights for realizing 2D‐materials‐based high‐performance energy harvesting and wearable devices.
Wearable smart electronic devices based on wireless systems use batteries as a power source. However, recent miniaturization and various functions have increased energy consumption, resulting in ...problems such as reduction of use time and frequent charging. These factors hinder the development of wearable electronic devices. In order to solve this energy problem, research studies on triboelectric nanogenerators (TENGs) are conducted based on the coupling of contact‐electrification and electrostatic induction effects for harvesting the vast amounts of biomechanical energy generated from wearer movement. The development of TENGs that use a variety of structures and materials based on the textile platform is reviewed, including the basic components of fibers, yarns, and fabrics made using various weaving and knitting techniques. These textile‐based TENGs are lightweight, flexible, highly stretchable, and wearable, so that they can effectively harvest biomechanical energy without interference with human motion, and can be used as activity sensors to monitor human motion. Also, the main application of wearable self‐powered systems is demonstrated and the directions of future development of textile‐based TENG for harvesting biomechanical energy presented.
Harvesting biomechanical energy from human motions enables sustainable power generation, which is critical to the advancement of wearable smart electronic devices based on wireless systems. Herein, a variety of triboelectric nanogenerators based on textile platforms are optimized to harvest biomechanical energy. These nanogenerators are lightweight, flexible, and stretchable can be integrated into real clothing.
A silk nanofiber‐networked bio‐triboelectric generator (Silk Bio‐TEG) is developed using an eco‐friendly and sustainable silk biomaterial with strong hydrogen bonding between peptide blocks. The ...electrospun Silk Bio‐TEG shows highly durable and reliable energy harvesting performances due to its notably high surface‐to‐volume ratio, mechanically super‐strong silk fibers, and fracture tolerant behavior of nanofiber‐networks.
In this work, a sulfur (S) vacancy passivated monolayer MoS2 piezoelectric nanogenerator (PNG) is demonstrated, and its properties before and after S treatment are compared to investigate the effect ...of passivating S vacancy. The S vacancies are effectively passivated by using the S treatment process on the pristine MoS2 surface. The S vacancy site has a tendency to covalently bond with S functional groups; therefore, by capturing free electrons, a S atom will form a chemisorbed bond with the S vacancy site of MoS2. S treatment reduces the charge‐carrier density of the monolayer MoS2 surface, thus the screening effect of piezoelectric polarization charges by free carrier is significantly prevented. As a result, the output peak current and voltage of the S‐treated monolayer MoS2 nanosheet PNG are increased by more than 3 times (100 pA) and 2 times (22 mV), respectively. Further, the S treatment increases the maximum power by almost 10 times. The results suggest that S treatment can reduce free‐charge carrier by sulfur S passivation and efficiently prevent the screening effect. Thus, the piezoelectric output peaks of current, voltage, and maximum power are dramatically increased, as compared with the pristine MoS2.
Piezoelectricity of sulfur vacancy passivated MoS2 nanosheets is much higher than that of pristine MoS2 nanosheets. Sulfur vacancies can be filled through a sulfur treatment and the resulting output power of the device generates a 10‐times higher power. This result offers a new approach to realize a MoS2 nanosheet‐based high‐performance piezoelectric nanogenerator for self‐powered wearable electronics.
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