Conductive Composite Fiber with Customizable Functionalities for Energy Harvesting and Electronic Textiles

Smart Textiles for Personalized Sports and Healthcare

Advances in wearable electronics and information technology drive sports data collection and analysis toward real-time visualization and precision. The growing pursuit of athleticism and healthy life makes it appealing for individuals to track their real-time health and exercise data seamlessly. While numerous devices enable sports and health monitoring, maintaining comfort over long periods remains a considerable challenge, especially in high-intensity and sweaty sports scenarios. Textiles, with their breathability, deformability, and moisture-wicking abilities, ensure exceptional comfort during prolonged wear, making them ideal for wearable platforms. This review summarized the progress of research on textile-based sports monitoring devices. First, the design principles and fabrication methods of smart textiles were introduced systematically. Textiles undergo a distinctive fiber-yarn-fabric or fiber-fabric manufacturing process that allows for the regulation of performance and the integration of functional elements at every step. Then, the performance requirements for precise sports data collection of smart textiles, including main vital signs, joint movement, and data transmission, were discussed. Lastly, the applications of smart textiles in various sports scenarios are demonstrated. Additionally, the review provides an in-depth analysis of the emerging challenges, strategies, and opportunities for the research and development of sports-oriented smart textiles. Smart textiles not only maintain comfort and accuracy in sports, but also serve as inexpensive and efficient information-gathering terminals. Therefore, developing multifunctional, cost-effective textile-based systems for personalized sports and healthcare is a pressing need for the future of intelligent sports.

Triboelectric Nanogenerators Based on Transition Metal Carbo-Chalcogenide (Nb2S2C and Ta2S2C) for Energy Harvesting and Self-Powered Sensing

With burgeoning considerations over energy issues and carbon emissions, energy harvesting devices such as triboelectric nanogenerators (TENGs) are developed to provide renewable and sustainable power. Enhancing electric output and other properties of TENGs during operation is the focus of research. Herein, two species (Nb2S2C and Ta2S2C) of a new family of 2D materials, Transition Metal Carbo-Chalcogenides (TMCCs), are first employed to develop TENGs with doping into Polydimethylsiloxane (PDMS). Compared with control samples, these two TMCC-based TENGs exhibit higher electric properties owing to the enhanced permittivity of PDMS composite, and the best performance is achieved at a concentration of 3 wt. ‰ with open circuit voltage (Voc) of 112 V, short circuit current (Isc) of 8.6 µA and charge transfer (Qsc) of 175 nC for Nb2S2C based TENG, and Voc of 127 V, Isc of 9.6 µA, and Qsc of 230 nC for Ta2S2C based TENGs. These two TENGs show a maximum power density of 1360 and 911 mW m-2 respectively. Moreover, the tribology performance is also evaluated with the same materials, revealing that the Ta2S2C/PDMS composite as the electronegative material presented a lower coefficient of friction (COF) than the Nb2S2C/PDMS composite. Their applications for energy harvesting and self-powered sensing are also demonstrated.

Self-Powered Hybrid Motion and Health Sensing System Based on Triboelectric Nanogenerators

Triboelectric nanogenerator (TENG) represents an effective approach for the conversion of mechanical energy into electrical energy and has been explored to combine multiple technologies in past years. Self-powered sensors are not only free from the constraints of mechanical energy in the environment but also capable of efficiently harvesting ambient energy to sustain continuous operation. In this review, the remarkable development of TENG-based human body sensing achieved in recent years is presented, with a specific focus on human health sensing solutions, such as body motion and physiological signal detection. The movements originating from different parts of the body, such as body, touch, sound, and eyes, are systematically classified, and a thorough review of sensor structures and materials is conducted. Physiological signal sensors are categorized into non-implantable and implantable biomedical sensors for discussion. Suggestions for future applications of TENG-based biomedical sensors are also indicated, highlighting the associated challenges.

Latest Innovations in 2D Flexible Nanoelectronics

2D materials with dangling-bond-free surfaces and atomically thin layers have been shown to be capable of being incorporated into flexible electronic devices. The electronic and optical properties of 2D materials can be tuned or controlled in other ways by using the intriguing strain engineering method. The latest and encouraging techniques in regard to creating flexible 2D nanoelectronics are condensed in this review. These techniques have the potential to be used in a wider range of applications in the near and long term. It is possible to use ultrathin 2D materials (graphene, BP, WTe2 , VSe2 etc.) and 2D transition metal dichalcogenides (2D TMDs) in order to enable the electrical behavior of the devices to be studied. A category of materials is produced on smaller scales by exfoliating bulk materials, whereas chemical vapor deposition (CVD) and epitaxial growth are employed on larger scales. This overview highlights two distinct requirements, which include from a single semiconductor or with van der Waals heterostructures of various nanomaterials. They include where strain must be avoided and where it is required, such as solutions to produce strain-insensitive devices, and such as pressure-sensitive outcomes, respectively. Finally, points-of-view about the current difficulties and possibilities in regard to using 2D materials in flexible electronics are provided.

A Review on the Progress in Core-Spun Yarns (CSYs) Based Textile TENGs for Real-Time Energy Generation, Capture and Sensing

This review is a critical analysis of the current state-of-the-art in core spun yarn textile triboelectric nanogenerators (CSY-T-TENGs) for self-powered smart sensing applications. The rapid expansion of wireless communication, flexible conductive materials, and wearable electronics over the last ten years is now demanding autonomous energy, which has created a new research space in the field of wearable T-TENGs. Current research is exploring T-TENGs made from CSYs as stable and reliable energy harvesters and sensing devices for modern wearable IoT platforms. CSY-TENGs are emerging as an important technology due to its simple structure, low cost, and excellent performance in converting mechanical energy into electrical energy and due to its sensing ability. This paper provides a critical review on current progress, it analyzes the unique advantages of CSYs T-TENGs over conventional T-TENGs, it describes fabrication techniques and discusses the materials used along with their properties and electrical performance characteristics, and it highlights the recent advancements in their integration with self-excitation circuits, charge storage devices and IoT-enabled smart sensing applications, such as environmental and health monitoring. In the conclusion, it discusses the challenges and future directions of CSYs T-TENGs and it provides a future road map for optimization, upscaling, and commercialization of the technology.

Conductive fibers for biomedical applications

Bioelectricity has been stated as a key factor in regulating cell activity and tissue function in electroactive tissues. Thus, various biomedical electronic constructs have been developed to interfere with cell behaviors to promote tissue regeneration, or to interface with cells or tissue/organ surfaces to acquire physiological status via electrical signals. Benefiting from the outstanding advantages of flexibility, structural diversity, customizable mechanical properties, and tunable distribution of conductive components, conductive fibers are able to avoid the damage-inducing mechanical mismatch between the construct and the biological environment, in return to ensure stable functioning of such constructs during physiological deformation. Herein, this review starts by presenting current fabrication technologies of conductive fibers including wet spinning, microfluidic spinning, electrospinning and 3D printing as well as surface modification on fibers and fiber assemblies. To provide an update on the biomedical applications of conductive fibers and fiber assemblies, we further elaborate conductive fibrous constructs utilized in tissue engineering and regeneration, implantable healthcare bioelectronics, and wearable healthcare bioelectronics. To conclude, current challenges and future perspectives of biomedical electronic constructs built by conductive fibers are discussed.

Natural Silkworm Cocoon-Based Hierarchically Architected Composite Triboelectric Nanogenerators for Biomechanical Energy Harvesting

Silk-based triboelectric nanogenerators (TENGs) have been demonstrated as an ideal platform for self-powered systems. The source of silk, Bombyx mori, entails a valuable ingredient, sericin (SS), viewed as a binder in composites. Interestingly, SS is rich in the amorphous region, possibly resulting in triboelectrification enhancement between the amorphous region and the crystallization region when subject to external pressure. However, most researchers remove the SS component when designing silk-TENGs to eliminate immunological responses as implantation in vivo through complicated degumming, rehydration, and dialysis procedures. Herein, integral SS retention was utilized to fabricate silk-TENGs without affecting the output performance. We designed, for the first time, an ultra-robust and natural silkworm cocoon layer (SCL)/polydimethylsiloxane (PDMS)-TENG as an energy harvester to scavenge waste energy from human motions. The working mechanisms and influence of operational parameters are explored and studied. Working in the contact-separation mode, the electrical outputs of the SCL/PDMS-TENG in terms of open-circuit voltage, short-circuit current, and power density reaches 126 V, 3 μA, and 216 mW/m2, respectively. The integrated self-charging TENG is demonstrated to power small electronic electronics and monitor human motions. This work widens a new dielectric material selection with SS retention to boost the output performance of TENGs for practical applications.

Wearable Triboelectric Nanogenerators Based on Polyamide Composites Doped with 2D Graphitic Carbon Nitride

Triboelectric nanogenerators (TENGs) have attracted many researchers’ attention with their remarkable potential despite the fact that the practical implementation requires further improvement in their electric performance. In this work, a novel graphene phase two-dimension material, graphitic carbon nitride (g-C₃N₄), was employed for the development of a TENG material with enhanced features. An electrospun nanofibrous PA₆₆ membrane doped with g-C₃N₄ was fabricated as a multifunctional TENG for harvesting different kinds of mechanical energy and detecting human motions. By utilizing the innovative 2D material in PA₆₆ solution for electrospinning, the as-made TENG showed a two times enhancement in electrical performance as compared to the control device, and also had the advantages of lightweight, softness, high porosity, and rugged interface properties. The assembled TENG with 4 cm² could light up 40 light-emitting diodes by gentle hand clapping and power electronic watches or calculators with charging capacitors. At a given impact force of 40 N and 3 Hz, the as-made TENG can generate an open-circuit voltage of 80 V, short current of ±3 µA, charge transfer of 50 nC, and a maximum power density of 45 mW/m² at a load resistance of 500 MΩ. The UV light sensitivity of TENG was also improved via g-C₃N₄ doping, showing that charge transfer is very sensitive with a two times enhancement with dopant. For the demonstration of applications, the g-C₃N₄ doped TENG was fabricated into an energy flag to scavenge wind energy and sensor devices for detecting human motions.

Flexible Sensory Systems: Structural Approaches

Biology is characterized by smooth, elastic, and nonplanar surfaces; as a consequence, soft electronics that enable interfacing with nonplanar surfaces allow applications that could not be achieved with the rigid and integrated circuits that exist today. Here, we review the latest examples of technologies and methods that can replace elasticity through a structural approach; these approaches can modify mechanical properties, thereby improving performance, while maintaining the existing material integrity. Furthermore, an overview of the recent progress in wave/wrinkle, stretchable interconnect, origami/kirigami, crack, nano/micro, and textile structures is provided. Finally, potential applications and expected developments in soft electronics are discussed.

Stretchable Thermoelectric-Based Self-Powered Dual-Parameter Sensors with Decoupled Temperature and Strain Sensing

Thermoelectric-based sensors with multifunctional sensing properties that can recognize different stimulations in a self-powered environment by converting low-grade heat into electrical energy have attracted increasing attention. However, the current thermoelectric-based multifunctional sensors are faced with issues such as limited preparation methods, complex structural designs, and hard decoupling, which greatly hinder their further development in the field of wearable electronics. Herein, we have fabricated novel free-standing self-powered temperature-strain sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanotube (CNT)/waterborne polyurethane (WPU) composite films through a simple drop-casting method. The composite films can maintain stable thermoelectric performance after washing 1000 times and withstand repeated bending and stretching. More importantly, based on the Seebeck effect arising from PEDOT:PSS/CNT composites, the assembled sensor successfully detects temperature changes and strain deformations under a self-powered condition. The decoupling of strain stimulation and temperature stimulation is mainly attributed to the good conductive network inside the composite film and the conductive bridge formed by PEDOT:PSS particles between CNTs when the composite film is stretched. Thus, the designed self-powered sensor with dual-parameter sensing prepared by a simple strategy has shown great potential in wearable electronics.