Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | School of Fashion and Textiles | en_US |
| dc.contributor.advisor | Xu, Bingang (SFT) | en_US |
| dc.creator | Xiao, Yana | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14165 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Design, fabrication, and application of triboelectric nanogenerators with two dimensional materials for energy harvesting and self-powered sensing | en_US |
| dcterms.abstract | Energy plays a fundamental role in human civilization, and the rapid expansion of smart city development, coupled with the drive for carbon neutrality, has attracted significant research attention towards sustainable, renewable, and flexible energy harvesting solutions. Among the newly developed renewable energy sources, nanogenerators, including piezoelectric, pyroelectric, and triboelectric nanogenerators, present promising avenues to scavenge the ubiquitous, continuous, and inexhaustible mechanical energy available in nature or biomechanical energy from human movements. Triboelectric nanogenerators (TENGs) have garnered considerable interest owing to their advantages, such as simple fabrication, cost-effectiveness, environmental friendliness, and versatile applications in portable wearable electronics and natural energy harvesting. However, the development of TENGs faces challenges related to energy efficiency limits and the need for enhanced functionalities to enable integration into various systems. The rapid advancements in multifunctional and wearable electronics have led to a growing demand for flexible and wearable power supply systems with high electric outputs and robust mechanical properties. Traditional chemical batteries, however, have become incompatible with the development of wearable electronics due to their inherent shortcomings, such as rigid complex structure, heavy weight, bulky volume, persistent recharging/replacement, and limited lifetime. | en_US |
| dcterms.abstract | The pivotal innovations of this research study include: | en_US |
| dcterms.abstract | Initially, two species of novel two-dimensional (2D) material Transition Metal Carbo-Chalcogenides (TMCCs), Nb₂S₂C and Ta₂S₂C, were first employed to be doped into Polydimethylsiloxane (PDMS) to explore its potential application for TENG and the best electrical performance was found at the concentration of 3 wt.‰, i.e., open circuit voltage (Voc) of 112 V, short circuit current (Isc) of 8.6 μA, and Charge Transfer (Qsc) of 175 nC for Nb₂S₂C doped TENG, while Voc of 130 V, Isc of 9.2 μA, and Qsc of 200 nC for Ta₂S₂C doped TENG. In addition, tests on the current and output power density of the Nb₂S₂C/Ta₂S₂C doped PDMS-TENG at resistances from 1 Ω to 1 GΩ under 20 N and 2 Hz impact showed that the maximum power density of 1360 mW/m2 and 911 mW/m² could be reached at 500 MΩ load respectively. Moreover, the Tribology Test revealed that the Ta₂S₂C doped PDMS, as the electronegative material, presented a lower Coefficient of Friction (COF) than Nb₂S₂C doped PDMS. | en_US |
| dcterms.abstract | Subsequently, a triboelectric nanogenerator (TENG) based on polyvinyl alcohol (PVA) hydrogel doped with an innovative two-dimensional material g-C3N4 was designed. This material serves as a cost-efficient, flexible electrode and a positive dielectric component for TENGs with varying morphologies. At a dopant concentration of 2.7 wt.%, the TENG demonstrated a peak-to-peak open-circuit voltage of 80 V in single-electrode mode, significantly outperforming the pristine PVA hydrogel TENG. To showcase its potential applications, the g-C3N4/PVA hydrogel TENG was employed as an electronic skin capable of tracking human body movements. Furthermore, mechanical energy harvesting devices were designed, fabricated, and evaluated with various shapes, such as discoid flakes, tubes, and spirals, operating in either single-electrode or contact-separation modes. | en_US |
| dcterms.abstract | Furthermore, g-C3N4 was doped into electrospinning membrane PA66 to fabricate a multifunctional TENG, and the as-made TENGs showed twice enhancement in electric performance with an open-circuit voltage of 80 V and a maximum power density of 45 mW/m², lighting up 40 light-emitting diodes (LEDs) and powering different kinds of portable electronics. Comparison of triboelectric properties has also been made under UV light and dark environments, showing that charge transfer is very sensitive with doping g-C3N4. As demonstration of applications, the prepared doped composite was also made into an energy flag to scavenge natural wind energy. | en_US |
| dcterms.abstract | Lastly, based on our previous research on a novel 2D material g-C3N4, we explored the influence of g-C3N4 hybrid dopants with PDMS on the performance enhancement of TENGs. More specifically, systematic experiments with different ratios of hybrid dopants were conducted, including Ag nanowire with g-C3N4, carbon nanotube with g-C3N4, and MXene with g-C3N4. The systematic and optimization studies showed that carbon nanotube (CNT)/g-C3N4 at the optimal ratio of 1:1 in PDMS composite presented open circuit voltage (Voc) at 122 V, short circuit current (Isc) at 5.8 μA, and charge transfer (Qsc) at 105 nC, while Ag/g-C3N4 at the ratio of 3:1 with 1 wt.% in PDMS composite presented the best performance with Voc of 92 V, Isc of 4.6 μA, Qsc of 49 nC, and power density of 1.45 W/m². For applications, we also designed a dish and an insole with multiple TENGs for pressure sensing and multichannel data acquisition, as well as an intelligent wireless system with Bluetooth module and mobile software. | en_US |
| dcterms.abstract | In summary, this work has successfully created flexible and wearable TENGs with significant potential to provide sustainable power supply for multifunctional wearable applications. The findings of this research contribute to the ongoing efforts in the field of triboelectric nanogenerators, offering novel design strategies and material solutions to improve energy harvesting efficiency and broaden the applicability of these promising devices. The insights gained from this work have the potential to impact the development of next-generation energy harvesting technologies, supporting the transition towards a more sustainable and resilient energy landscape. | en_US |
| dcterms.extent | xli, 264 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2025 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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