Conductive Fabric-Based Stretchable Hybridized Nanogenerator for

Mar 18, 2016 - At first, AgNWs with a high aspect ratio were prepared via a simple chloride-assisted solvothermal process. The AgNWs were placed betwe...
0 downloads 0 Views 9MB Size
Download PDF
Subscriber access provided by Washington University | Libraries

Article

Conductive Fabric Based Stretchable Hybridized Nanogenerator for Scavenging Biomechanical Energy Kewei Zhang, Zhong Lin Wang, and Ya Yang ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.6b01170 • Publication Date (Web): 18 Mar 2016 Downloaded from http://pubs.acs.org on March 19, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Nano is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

Conductive Fabric Based Stretchable Hybridized Nanogenerator for Scavenging Biomechanical Energy Kewei Zhang, † Zhong Lin Wang,†,║,* and Ya Yang †,* †

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences; National Center for

Nanoscience and Technology, Beijing 100083, P. R. China ║

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia

30332-0245, United States *To whom correspondence should be addressed: Emails: [email protected]; [email protected] ABSTRCT: We demonstrate a stretchable hybridized nanogenerator based on highly conductive fabric of glass fibers (GFs) / silver nanowires (AgNWs) / polydimethylsiloxane (PDMS). Including a triboelectric nanogenerator and an electromagnetic generator, the hybridized nanogenerator can deliver output voltage/current signals from stretchable movements by both the triboelectrification and the electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. As compared with the individual energy harvesting units, the hybridized nanogenerator has a better charging performance, where a 47 µF capacitor can be charged to 2.8 V in only 16 s. The hybridized nanogenerator can be integrated with a bus grip for scavenging wasted biomechanical energy from human body movements to solve the power source issue of some electric devices in pure electric bus. KEYWORDS: conductive fabric, Ag nanowires, stretchable nanogenerator, biomechanical energy.

ACS Paragon Plus Environment

1

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 15

With the fast expansion of cell phone-based personal information platform, there has been increased interest in the possibilities of obtaining power from human activities and our surrounding environment.13

Stretchable movement is widely available in our local environment, such as in buses with abundant

passenger flow, which may provide a promising solution to solve the power source issue of some electric devices in the pure electric bus by harvesting the wasted biomechanical energy from the bus grips. Although nanogenerators capable of scavenging energy from walking, vibration, wind, rotating tire, flowing water, etc. have been substantially exploited,4-10 there has been no report on a hybridized nanogenerator capable of scavenging biomechanical energy from stretchable movements. For realization of such a nanogenerator, the first issue is how to create stretchable structure, and then stretchable conductor is highly desired with recoverable conductivity under deformation. Recently, several investigations on stretchable conductors of metal nanowire networks and conducting polymers have been reported for possibility of being utilized in flexible devices.11-18 Although each of them exhibits some kinds of attractive features, a simple, green and low-cost procedure that can be easily processed is still required. Moreover, it is also a great challenge to satisfy the indispensable but exclusive characteristics of both conductivity and stretchability at the same time. In this paper, we fabricated a stretchable hybridized nanogenerator that is based on highly conductive fabric with sandwiched structure of glass fibers (GFs) / silver nanowires (AgNWs) / polydimethylsiloxane (PDMS). At first, AgNWs with high aspect ratio were prepared via a simple chloride-assisted solvothermal process. The AgNWs were placed between GFs and PDMS to achieve a sandwiched configuration, which makes the conductive fabric (with a line resistance of less than 2.5 Ωcm−1) mechanically flexible and toughened. The conductive fabric was adopted as triboelectric layer to construct a stretchable hybridized electromagnetic-triboelectric nanogenerator for scavenging wasted biomechanical energy from stretchable movements. The stretchable hybridized nanogenerator can generate electricity by both the triboelectrification and electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. The hybridized nanogenerator has a significantly better charging performance than that of the individual energy harvesting units, where it can be integrated in a bus grip to scavenge the wasted biomechanical energy for solving the power source issues of some electric devices in the pure electric bus.

RESULTS AND DISCUSSION Figure 1a displays a photograph of the as-fabricated conductive fabric which has a dimension of 12 cm × 1 cm. Among the recently investigated metal nanowire networks, AgNWs have proven to be excellent conductor with high conductivity and low brittleness.19,20 Herein, highly conductive fabric was obtained through dip-coating of AgNWs ink on glass fibers. A simple chloride-assisted solvothermal ACS Paragon Plus Environment

2

Page 3 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

method was adopted to prepare desirable AgNWs. In the reaction, Ag+ cations are reduced by ethylene glycol (EG) to fivefold Ag0 nuclei, where the selective adsorption of both the Cl- anions and poly(vinylpyrrolidone) (PVP) leads to the uniaxial elongation of Ag0 nuclei into very-long AgNWs.21,22 Figure 1b shows a scanning electron microscopy (SEM) image of the as-prepared AgNWs, where the AgNWs have average diameter of ∼ 100 nm and length in the range of 10-30 µm. After coating the AgNWs ink (insert of Figure 1b) on glass fibers, a dense network of randomly distributed AgNWs is observed (Figure 1c). The high aspect ratio of AgNWs allows electrons to transfer easier across the fabric without overcoming the nanowire junctions.14 To investigate the mechanical bending characteristic of the conductive fabric, we measured its resistance by four circles as a function of bending distance: 12 → 10 → 8 → 6 → 4 → 3 → 1 cm. Figure 1d illustrates three typical bending states of the same conductive fabric. After repeated bending, no delamination of AgNWs is observed. As seen from Figure 1e, the resistance increases or decreases slightly when the bending direction is inward or outward, respectively. The change of resistance becomes smaller as the number of bending cycles increased. In the whole bending process, the resistance maintains less than 30 Ω, corresponding to a line resistance of less than 2.5 Ωcm−1. These results indicate that the highly conductive fabric possesses characteristics of flexibility and tenability. To visually demonstrate its performance as stretchable conductor, a flexible circuit was constructed to power a light-emitting diode (LED). The green LED remained lit with the same illumination intensity in whole bending process of the conductive fabric, as displayed in Figure 1f and Movie file-S1 (see the Supporting Information). Based on the conductive fabric, a stretchable nanogenerator has been designed, as schematically illustrated in Figure 2a. A 0.25-mm-thick PET sheet was deposited with ITO before covering a fluorinated ethylene propylene (FEP) thin film as the upper framework. The as-prepared conductive fabric covered with a thin PDMS film was attached on the other 0.25-mm-thick PET sheet as the lower framework. The two frameworks are connected face to face through two elastics at the bilateral. Thus, the packaged device possesses an arched structure (Figure 2b and 2c), which is beneficial for harvesting energy during stretchable movements. By comparing the length of the device before and after stretching, the stretching ratio of the device can be calculated to be approximately 18%. To maximize the efficiency of energy harvesting, a rectangular Cu coil and NdFeB magnet in the same size was fixed on the outboards of the upper and lower frameworks. Accordingly, the stretchable nanogenerator consists of a triboelectric nanogenerator (TENG) and an electromagnetic nanogenerator (EMG). From SEM image of the conductive fabric after coating a thin PDMS film (Figure 2d), it can be seen that only sparse AgNWs are observed on the surface of PDMS, the majority of AgNWs is embedded into the PDMS. The highly cross-linked PDMS film not only makes the fragile AgNWs network mechanically ACS Paragon Plus Environment

3

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 15

robust but also acts as a triboelectric material of the TENG. PDMS and FEP are materials with different tribo-electricity, and FEP is much more triboelectrically positive than PDMS. When a pulling force is applied, the nanogenerator stretches gradually from the arched structure to the joint structure (insert of Figure 2b), generating current flow by both the triboelectrification and the electromagnetic induction. Figure 2e depicts the working principle of the hybridized nanogenerator during stretchable movements. Initially, the top FEP and the bottom PDMS are fully contacted with positive charges on FEP and equivalent negative charges on PDMS owing to triboelectrification (step-I). At this stage, no current flow occurs due to electrostatic equilibrium. Once the pulling force is withdrawn, the arched structure of the nanogenerator restores gradually and the contacted surfaces are separated. The electric potential difference between the FEP and the PDMS will drive the electrons to flow from the ITO electrode to the AgNWs electrode and generate an instantaneously opposite potential to balance the electric field, producing current signals in the TENG (step-II). When the nanogenerator is completely restored the arched structure, the electric field between the FEP and the PDMS is fully balanced by the opposite electric field between the ITO and the AgNWs, achieving another electrostatic equilibrium without current signals (step-III). Along with stretching the nanogenerator again, the FEP and the PDMS get close to each other, producing reversed current signals (step-IV). Until the nanogenerator is completely stretched to the joint structure, the FEP and the PDMS are fully contact, and a full cycle of electricity generation finishes and another cycle starts. Simultaneously, during the stretchable movements, the magnetic flux crossing the coil decreases or increases, inducing current flow in the coil due to the Lenz’s law. To quantitatively measure the electrical performance, one side of the stretchable hybridized nanogenerator was anchored and the other side was connected to a programmable linear motor (acceleration: 20 m/s2, maximum speed: 0.5 m/s). Figure 3a presents the measured output voltage of the TENG with resistance of 100 MΩ in parallel, where the peak value reaches 125 V. The measured shortcircuit current of the TENG reached as high as 48 µA, as depicted in Figure 3b. A slight oscillation is observed owing to the destabilization during the stretchable movements. Figure 3c illustrates output performance of the nanogenerator under different external loads. Owing to the Ohmic loss, the current decreases with increasing the loading resistance. The output power reaches the maximum value of 1.9 mW at loading resistance of 8 MΩ. Besides the output of TENG, the stretchable movements can produce alternating current flow in the coils. For the EMG, the output voltage and current were measured to be 6.3 V and 8.4 mA, respectively, as presented in Figure 3d and 3e. Maximum output power of 10.5 mW was obtained at matched loading resistance of 800 Ω. From the above data, it can be noticed that the output impedances of the TENG and the EMG are ACS Paragon Plus Environment

4

Page 5 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

highly unmatched, which would cause power consumption when combining these two parts as a hybridized power source. Because the instantaneous voltage and current of the EMG are proper for powering common electronics without respect to the energy density, the TENG was power-managed with a commercial transformer, designated as TENG (t), to realize lower output impedance. After using the commercial transformer, the peak value of the output voltage and current can be adjusted to 5.7 V and 0.28 mA, respectively, as depicted in Figures 4a and 4b. For the TENG (t), the output current also decreases with increasing the loading resistance, and the output power reaches the maximum value of 0.34 mW with impedance of 20 kΩ (Figure 4c). Although a portion of power is consumed by transformer, the achieved electrical characteristic of TENG (t) is more conformable for its combination with the EMG due to the lower impedance. The combining effect was confirmed by comparing the different charging performances of a 47 µF capacitor by using the individual energy harvesting units and the hybridized nanogenerator, as illustrated in Figure 4d. The result indicates that the hybridized nanogenerator of TENG (t) // EMG exhibits much better charging performance than that of the individual energy harvesting units, where the capacitor can be easily charged to 2.8 V in only 16 s. To demonstrate that the hybridized nanogenerator can be utilized as a power source, it has been integrated with a bus grip for scavenging the wasted biomechanical energy from human locomotion to achieve self-powered functions of some electronic devices in the electric bus, as displayed in Figure 5a. Electricity can be generated if someone stretches the bus grip. The pulsed outputs can be utilized to directly power light sources or be stored in a Li-ion battery as a persisted energy supplier for solving the issue of power sources for some electronic devices such as vehicle-mounted DVD, MP3, temperature and humidity sensor, control circuit, and so on. From comparison of the normal and the nanogeneratorbased grip (Figure 5b), it can be seen that the extrinsic feature of grip remains the same. However, the invented nanogenerator can effectively scavenge the wasted biomechanical energy from human body movements under the speed changes of the bus. Figure 5c illustrates a home-made nanogenerator-based bus grip for driving a LEDs-based optical fiber. During stretching, the LEDs at the two ends of the optical fiber can be lighted up, resulting in that the produced green light can effectively go through all the optical fiber, as demonstrated in Figure 5d.

CONCLUSIONS In summary, conductive fabric of GFs/AgNWs/PDMS with a line resistance of less than 2.5 Ωcm−1 was fabricated based on very-long AgNWs. The conductive fabric was adopted as triboelectric layer to construct a stretchable hybridized nanogenerator. The hybridized nanogenerator can generate electricity from stretchable movements by both the triboelectrification and the electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. The TENG can deliver a ACS Paragon Plus Environment

5

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 15

peak output power of 1.9 mW under a loading resistance of 8 MΩ and the EMG can deliver a peak output power of 10.5 mW under a loading resistance of 800 Ω. By using a transformer, the impedance of TENG can be decreased to be more conformable for its combination with the EMG. The hybridized nanogenerator has a much better charging performance than that of the individual energy harvesting units (TENG or EMG). The hybridized nanogenerator can be integrated with a bus grip for effectively scavenging wasted biomechanical energy to realize some self-powered functions in the electric bus.

EXPERIMENTAL SECTION Materials. Silver nitrate (AgNO3), sodium chloride (NaCl), and ethylene glycol (EG) were purchased from Sinopharm Chemical Reagent Co. Ltd. Poly(vinylpyrrolidone) (PVP, avg Mw = 1300 000) was purchased from Sigma-Aldrich Co. LLC. All chemicals were used without further purification. Preparation of AgNWs. The AgNWs were prepared by a chloride-assisted solvothermal process. In a typical procedure, 2.9 g of PVP was thoroughly dissolved in 92 mL of EG under stirring at room temperature to obtain a transparent and uniform solution. Then, 5 mL of AgNO3/EG solution (0.9 M) and 3 mL of NaCl/EG solution (0.01 M) were added into the above PVP/EG solution. After stirring for several minutes, the mixed solution was transferred into the Teflon-lined autoclave and solvothermally treated at 195 oC for 15 min. The resulting white precipitate was retrieved by centrifugation and rinsed with deionized water and ethanol for several times. Finally, the obtained product was re-dispersed in ethylene glycol as AgNWs ink for further processing. Preparation of conductive fabric. Firstly, the GFs was thoroughly cleaned by abundant ethanol and placed flat as substrate. Then, the AgNWs ink (5% AgNWs by mass) was dip-coated onto the glass fabric. After several minutes drying in air, the GFs/AgNWs was exposed with high intensity light for 5 s at room temperature. Finally, the GFs/AgNWs was covered with a thin PDMS film using Sylgard 184 (Dow Corning) by mixing the fluid PDMS elastomer and corresponding cross-linker with a ratio of 10:1 (w/w). After degassed for 10 min, the GFs/AgNWs/PDMS was thermally cured at 80oC for 1 h in a vacuum oven. The morphology of AgNWs and conductive fabric was examined by scanning electron microscopy (SEM, Hitachi SU8020, 10 kV). Fabrication of nanogenerator. Firstly, two PET sheets with dimensions of 200 mm × 68 mm × 0.25 mm were cut with a laser cutting machine as the double-layered substrates of the device. On the first substrate, ITO electrode was deposited by pulsed vapor deposition (PVD). Then, a FEP thin film dimensions of 200 mm × 40 mm × 0.03 mm was attached onto the ITO electrode as the triboelectric material. On the other substrate, the as-prepared conductive fabric and a PDMS film with dimensions of ACS Paragon Plus Environment

6

Page 7 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

200 mm × 40 mm × 0.2 mm were attached in sequence as one of the triboelectric layers. The two substrates were separated by two elastics at the bilateral. After the framework of the device was constructed, a rectangle Cu coil with turns of about 2000 and a rectangle NdFeB permanent magnet with length of 30 mm, width of 10 mm and height of 1 mm were fixed on the outboards of the two substrates, respectively. Two Cu wires were connected to the inside and outside of the coil as the electrodes of the EMG part. Conflict of Interest: The authors declare no competing financial interest. Acknowledgment. This work was supported by Beijing Natural Science Foundation (2154059), the China Postdoctoral Science Foundation (Grant No. 2015M570988), the National Natural Science Foundation of China (Grant No. 51472055, Grant No. 61404034), External Cooperation Program of BIC, Chinese Academy of Sciences (Grant No. 121411KYS820150028), the 2015 Annual Cooperative Project between Chinese Academy of Sciences and Taiwan Industrial Technology Research Institute (CAS-ITRI201501), the 2015 Annual Beijing Talents Fund (Grant No. 2015000021223ZK32), and the "thousands talents" program for the pioneer researcher and his innovation team, China. The corresponding patent has been submitted based on the research presented here. Supporting Information Available: Additional movie file includes the demonstration of a conductive fabric as conductor for powering a LED. This material is available free of charge via the Internet at http://pubs.acs.org.

ACS Paragon Plus Environment

7

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 15

REFERENCES AND NOTES 1. Wang, Z. L.; Chen, J.; Lin, L. Progress in Triboelectric Nanogenerators as a New Energy Technology and Self-Powered Sensors. Energy Environ. Sci. 2015, 8, 2250-2282. 2. Niu, S.; Wang, X.; Yi, F.; Zhou, Y. S.; Wang, Z. L. A Universal Self-Charging System Driven by Random Biomechanical Energy for Sustainable Operation of Mobile Electronics. Nat. Commun. 2015, 6, 8975. 3. Jung, W. S.; Kang, M. G.; Moon, H. G.; Baek, S. H.; Yoon, S. J.; Wang, Z. L.; Kim, S. W.; Kang, C. Y. High Output Piezo/Triboelectric Hybrid Generator. Sci. Rep. 2015, 5, 9309. 4. Zhang, K.; Wang, X.; Yang, Y.; Wang, Z. L. Hybridized Electromagnetic Triboelectric Nanogenerator for Scavenging Biomechanical Energy for Sustainably Powering Wearable Electronics. ACS Nano 2015, 9, 3521-3529. 5. Quan, T.; Wu, Y.; Yang, Y. Hybrid Electromagnetic-Triboelectric Nanogenerator for Harvesting Vibration Energy. Nano Res. 2015, 8, 3272-3280. 6. Wang, S.; Mu, X.; Yang, Y.; Sun, C.; Gu, A. Y.; Wang, Z. L. Flow-Driven Triboelectric Generator for Directly Powering a Wireless Sensor Node. Adv. Mater. 2015, 27, 240-248. 7. Fan, F.-R.; Tian, Z.-Q.; Wang, Z. L. Flexible Triboelectric Generator. Nano Energy 2012, 1, 328-334. 8. Chen, J.; Yang, J.; Li, Z.; Fan, X.; Zi, Y.; Jing, Q.; Guo, H.; Wen, Z.; Pradel, K. C.; Niu, S.; Wang, Z. L. Networks of Triboelectric Nanogenerators for Harvesting Water Wave Energy. ACS Nano 2015, 9, 3324-3331. 9. Guo, H.; Leng, Q.; He, X.; Wang, M.; Chen, J.; Hu, C.; Xi, Y. A Triboelectric Generator Based on Checker-Like Interdigital Electrodes with a Sandwiched PET Thin Film for Harvesting Sliding Energy in All Directions. Adv. Energy Mater. 2015, 5, 1400790. 10. Liu, G.; Leng, Q.; Lian, J.; Guo, H.; Yi, X.; Hu, C. Notepad-Like Triboelectric Generator for Efficiently Harvesting Low-Velocity Motion Energy by Interconversion between Kinetic Energy and Elastic Potential Energy. ACS Appl. Mater. Interfaces 2015, 7, 1275-1283. 11. Lee, S.; Shin, S.; Lee, S.; Seo, J.; Lee, J.; Son, S.; Cho, H. J.; Algadi, H.; Al-Sayari, S.; Kim, D. E.; Lee, T. Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics. Adv. Funct. Mater. 2015, 25, 3114-3121. 12. An, B. W.; Hyun, B. G.; Kim, S. Y.; Kim, M.; Lee, M. S.; Lee, K.; Koo, J. B.; Chu, H. Y.; Bae, B. S.; Park, J. U. Stretchable and Transparent Electrodes Using Hybrid Structures of Graphene-Metal Nanotrough Networks with High Performances and Ultimate Uniformity. Nano Lett. 2014, 14, 63226328. 13. Chandrashekar, B. N.; Deng, B.; Smitha, A. S.; Chen, Y.; Tan, C.; Zhang, H.; Peng, H.; Liu, Z. ACS Paragon Plus Environment

8

Page 9 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

Roll-to-Roll Green Transfer of CVD Graphene onto Plastic for a Transparent and Flexible Triboelectric Nanogenerator. Adv. Mater. 2015, 27, 5210-5216. 14. Ye, S.; Rathmell, A. R.; Chen, Z.; Stewart, I. E.; Wiley, B. J. Metal Nanowire Networks: the Next Generation of Transparent Conductors. Adv. Mater. 2014, 26, 6670-6687. 15. Gaikwad, A. M.; Zamarayeva, A. M.; Rousseau, J.; Chu, H.; Derin, I.; Steingart, D. A. Highly Stretchable Alkaline Batteries Based on an Embedded Conductive Fabric. Adv. Mater. 2012, 24, 50715076. 16. Mates, J. E.; Bayer, I. S.; Palumbo, J. M.; Carroll, P. J.; Megaridis, C. M. Extremely Stretchable and Conductive Water-Repellent Coatings for Low-Cost Ultra-Flexible Electronics. Nat. Commun. 2015, 6, 8874. 17. Hong, S.; Lee, H.; Lee, J.; Kwon, J.; Han, S.; Suh, Y. D.; Cho, H.; Shin, J.; Yeo, J.; Ko, S. H. Highly Stretchable and Transparent Metal Nanowire Heater for Wearable Electronics Applications. Adv. Mater. 2015, 27, 4744-4751. 18. Ma, R.; Kang, B.; Cho, S.; Choi, M.; Baik, S. Extraordinarily High Conductivity of Stretchable Fibers of Polyurethane and Silver Nanoflowers. ACS Nano 2015, 9, 10876-10886. 19. Xu, F.; Zhu, Y. Highly Conductive and Stretchable Silver Nanowire Conductors. Adv. Mater. 2012, 24, 5117-5122. 20. Ran, Y.; He, W.; Wang, K.; Ji, S.; Ye, C. A One-Step Route to Ag Nanowires with a Diameter Below 40 nm and an Aspect Ratio Above 1000. Chem. Commun. 2014, 50, 14877-14880. 21. Jiu, J.; Sugahara, T.; Nogi, M.; Suganuma, K. Ag Nanowires: Large-Scale Synthesis via a TraceSalt-Assisted Solvothermal Process and Application in Transparent Electrodes. J. Nanopart. Res. 2013, 15, 1588. 22. Zeng, X.; Zhou, B.; Gao, Y.; Wang, C.; Li, S.; Yeung, C. Y.; Wen, W. Structural Dependence of Silver Nanowires on Polyvinyl Pyrrolidone (PVP) Chain Length. Nanotechnology 2014, 25, 495601.

ACS Paragon Plus Environment

9

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 15

FIGURES

Figure 1. (a) Photograph of a 12-cm-long conductive fabric. (b) SEM image of as-prepared AgNWs. Insert shows an optical image of the AgNWs ink. (c) SEM image of the conductive fabric based on AgNWs. Insert shows enlarged view of the fabric surface. (d) Photographs of the conductive fabric in different bending distance. (e) The relationship between line resistance and bending distance of the conductive fabric. (f) Photographs of a conductive fabric as conductor for powering a LED.

ACS Paragon Plus Environment

10

Page 11 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

Figure 2. (a) Schematic diagram of the stretchable nanogenerator. (b, c) Photographs of the hybridized nanogenerator. (d) SEM image of the triboelectric layer of GFs/AgNWs/PDMS. Insert shows enlarged view of the triboelectric layer. (e) Schematic illustration of working principle of the stretchable nanogenerator.

ACS Paragon Plus Environment

11

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 15

Figure 3. (a) Voltage of the TENG measured with resistance of 100 MΩ in parallel. (b) Output current of the TENG. (c) Dependence of output current and output power of the TENG on external loading resistance. (d) Output voltage of the EMG. (e) Output current of the EMG. (f) Dependence of output current and output power of the EMG on external loading resistance.

ACS Paragon Plus Environment

12

Page 13 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

Figure 4. (a) Output voltage of the TENG with transformer. (b) Output current of the TENG with transformer. (c) Dependence of output current and output power of the TENG with transformer on the external loading resistance. (d) Measured voltage of a 47 µF capacitor charged by the TENG without transformer, TENG with transformer, EMG, and the hybridized nanogenerator (EMG and TENG with a transformer in parallel).

ACS Paragon Plus Environment

13

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 15

Figure 5. (a) Schematic diagram of the hybridized nanogenerator based bus grips for scavenging the wasted biomechanical energy from human body movements. (b) Photograph of the bus grip before and after embedding the stretchable nanogenerator. (c) Photograph of a nanogenerator-based bus grip and a LEDs-based optical fiber. (d) Photograph of a LEDs-based optical fiber that can be lighted up by the hybridized nanogenerator.

ACS Paragon Plus Environment

14

Page 15 of 15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

TOC

ACS Paragon Plus Environment

15