Boosted triboelectric performance in stretchable nanogenerators via 2D MXene-Driven electron accumulation and LiNbO₃-assisted charge transfer

Abstract

The development of piezoelectrically enhanced triboelectric hybrid nanogenerators (PET-HNGs) has garnered considerable attention for their potential in energy harvesting. However, their performance in stretchable applications across diverse environments, such as air and water, remains limited due to the lack of high-performance, stretchable material compositions and a comprehensive understanding of the charge transfer mechanism involved. To address these challenges, we have designed a high-performance, stretchable nano-/micro-composite film by embedding 2D MXene nanosheets and piezoelectric LiNbO₃ microparticles into an Ecoflex polymer matrix. Quantum mechanical calculations revealed that MXene nanosheets significantly increase electron density near the Fermi level, while LiNbO₃ microparticles enhance electron transfer during contact electrification with polydimethylsiloxane (PDMS). This synergistic effect resulted in a substantial enhancement of the triboelectric energy harvesting performance, with the composite film exhibiting a 355 % increase in voltage, a 324 % increase in current, and a 100 % boost in power output density compared to systems using pure Ecoflex based TENGs. The fabricated PET-HNG demonstrated remarkable output metrics, including a voltage of 455 V, current of 140 μA, power output density of 15.6 W m⁻², and an energy conversion efficiency of 78.5 %, all while maintaining exceptional performance stability even under mechanical stretching.

This stretchable nanogenerator shows great potential as a self-powered wearable sensor for real-time biomechanical monitoring in various environments, including air and underwater. This innovation paves the way for the development of next-generation wearable electronics and energy harvesting devices.