Efficient Triboelectric Nanogenerators with on-demand Auxetic Structure achieving Deformation Matching in Wearable Devices

Abstract

Burgeoning triboelectric nanogenerators (TENGs) receive considerable attentions as versatile and efficient devices for mechanical energy harvesting. Significant challenges remain in enhancing the power-generation efficiency of TENG. Here, an innovative Auxetic Triboelectric Nanogenerator (Auxetic-TENG) incorporating metamaterials with Negative Poisson’s ratio was designed to address the challenges of integrated low power-density and deformation mismatch in complex bending operations. The Auxetic-TENG employs a concave horseshoe-shaped silicone elastomer with synclastic effects as the outer framework of the positive triboelectric layer. The positive triboelectric layer comprises aminated collagen-aggregates composite, while the negative triboelectric layer is constructed from polydimethylsiloxane. The positive and negative triboelectric layers are further enhanced by microstructured convex surface designs, boosting the overall power output. The synclastic effects of the framework induce lateral displacement under uniaxial stretching, significantly improving both electromechanical conversion efficiency and conformability to the human body’s joint-bending. Surprisingly, the Auxetic-TENG derived wearable device achieves an open-circuit voltage of 47 V, which is 2.2 times higher than that of conventional contact-separation TENGs. Additionally, the power density of the Auxetic-TENG can achieve 145.3 mW·m⁻². Comprehensive experimental evaluations confirm the superior performances of the Auxetic-TENG under various bending and stress conditions, demonstrating its promising potential for real-time monitoring applications in healthcare management.