Ferroelectricity-Coupled\n2D-MXene-Based Hierarchically\nDesigned High-Performance Stretchable Triboelectric Nanogenerator

Abstract

Triboelectric nanogenerators based on the state-of-the-art\nfunctional\nmaterials and device engineering provide an exciting platform for\nfuture multifunctional electronics, but it remains challenging to\nrealize due to the lack of in-depth understanding on the functional\nproperties of nanomaterials that are compatible with microstructural\nengineering. In this study, a high-performance stretchable (∼60%\nstrain) triboelectric nanogenerator is demonstrated <i>via</i> an interlocked microstructural device configuration sandwiched between\nsilver-nanowire-(Ag-NW) electrodes and hierarchically engineered spongy\nthermoplastic polyurethane (TPU) polymer composite with ferroelectric\nbarium-titanate-coupled (BTO-coupled) 2D MXene (Ti₃C₂T_<i>x</i>) nanosheets. The use of MXene\nresults in an increase in the dielectric constant whereas the dielectric\nloss is lowered <i>via</i> coupling with the ferroelectricity\nof BTO, which increases the overall output performance of the nanogenerator.\nThe spongy nature of the composite film increases the capacitance\nvariation under deformation, which results in improved energy-conversion\nefficiency (∼79%) and pressure sensitivity (4.6 VkPa^–1 and 2.5 mAkPa^–1) of the device. With the quantum-mechanically\ncalculated electronic structure, the device converts biomechanical\nenergy to electrical energy and generates an open-circuit output voltage\nof 260 V, short-circuit output current of 160 mA/m², and\nexcellent power output of 6.65 W/m², which is sufficient\nto operate several consumer electronics. Owing to its superior pressure\nsensitivity and efficiency, the device enables a broad range of applications\nincluding real-time clinical human vital-sign monitoring, acoustic\nsensing, and multidimensional gesture-sensing functionality of a robotic\nhand. Considering the ease of fabrication, excellent functionality\nof the hierarchical polymer nanocomposite, and outstanding energy-harvesting\nperformance of nanogenerators, this work is expected to stimulate\nthe development of next-generation self-powered technology.