Hydrogen-bond enhanced interior charge transport and trapping in all-fiber triboelectric nanogenerators for human motion sensing and communication

Abstract

Maximizing charge density output within confined tribolayer areas is crucial for advancing triboelectric nanogenerator (TENG) performance. While conventional methods primarily focus on enhancing current density by modifying the surface properties of tribo-surfaces, the impact of dipole-dipole interactions between polymer molecular chains in the fibrous tribomaterials has been underexplored. This study reveals that intermolecular dipole-dipole interactions, mediated by hydrogen bonding between chitosan and nylon66 molecular chains, serve as effective bridging mechanisms that substantially boost TENG current density. Furthermore, we developed a breathable and antibacterial electrode by depositing silver nanowires (AgNWs) on the tribolayer surfaces. To prevent air breakdown resulting from excessively high current density, multiwalled carbon nanotubes (MWCNTs) were integrated to enhance electron transfer and storage. The structure we constructed achieved an optimized performance with a high voltage of 335 V, current density of 194.5 mA m −2 and power density of 65.1 W m −2 , which demonstrates outstanding performance compared to previously obtained results. Finally, the prepared SWS-TENG was attached to the fingertips, wrist, and neck to track the physiological signals of the human state during standing, walking, and running. In addition, the integration of Morse code functionality introduces new possibilities for healthcare, particularly for non-verbal patients, enabling non-invasive communication of symptoms and emotions. This technology demonstrates significant potential as a versatile and non-invasive tool for point-of-care (PoC) and biomedical applications when deployed on various parts of the human body. Fig. 1. Overall diagram and working mechanism of fabricated SWS-TENG. a Assembly diagram of SWS-TENG. b Illustration of enhanced interior charge transportation and air break down effect. c Diagram of promoted interior charge transportation and trapping. Fig. 1a shows a schematic of the SWS-TENG structure, where all the hybridized fiber membranes were prepared through electrospinning, with AgNWs anchored onto the surface of Nylon66/chitosan and PVDF/MWCNT serving as the electrodes. This configuration endows the system with excellent air permeability and antiviral properties, as illustrated in Fig. S1a ,b. Additionally, different proportions of chitosan were blended with nylon66 to tune the electron-positive charge affinities. A small amount of MWCNTs was added to the PVDF as an electron-withdrawing counterpart to prevent air breakdown. Finally, insulation layers were installed to stop electron leakage and minimize the influence of humidity. Fig. 1b displays the mechanism of charge transportation in areas away from the contact interface and the decreased efficiency of the SWS-TENG caused by air breakdown effects. Fig. 1c shows how the performance of the SWS-TENG is enhanced through the promotion of charge transportation and trapping. • An all-fibrous, sensor based on a triboelectric nanogenerator was proposed. • Intermolecular hydrogen bonds acted as bridges to facilitate the charge transfer. • It shows a current density of 194.5 mA m −2 and power density of 65.1 W m −2 . • It could light up 124 commercial LEDs within an area of 2.25 cm −2 . • It effectively monitors human motion and serves as a communication tool.

Topics & Concepts