Auxetic Structure-Assisted Triboelectric Nanogenerators for Efficient Energy Collection and Wearable Sensing

Triboelectric nanogenerators (TENGs) are recognized for energy conversion efficiency and applications including electronics and energy storage devices. This study introduces a groundbreaking development in TENG by incorporating negative Poisson's ratio metamaterials to fabricate auxetic-assisted triboelectric nanogenerators (Auxetic-TENG), subversively overcoming the low power density of traditional materials. Subtly, an integrated layer-by-layer-assembly and core-shell accumulation strategy is employed to create a synclastic polytetrafluoroethylene negative friction shell-skeleton, into which positive Poisson's ratio nature collagen aggregate (CA) foam is inwardly embedded as the positive friction core-material. Surprisingly, the on-demand introduction of metamaterials in synergy with CA significantly increases the contact area and mechanical energy absorption of the Auxetic-TENG under pressure. This enhancement in the conversion efficiency of mechanical to electricity capitalizes on the contraction origins of negative Poisson's ratio metamaterials, integrated with the expansion characteristics of the positive Poisson's ratio materials within the structure, facilitating the synergistic compression of the positive and negative friction stratum. Consequently, Auxetic-TENG achieves an open-circuit voltage of 85 V, an overturning four times compared to conventional contact-separation TENG, and a power density of 4.2 W m-2. Application experiments demonstrate the superior performance of auxetic-TENG under various compression ratios and stress conditions, highlighting its potential for real-time monitoring in healthcare applications. This study introduces a groundbreaking development in TENG by incorporating negative Poisson's ratio metamaterials to create Auxetic-TENG, overcoming the low power density of traditional materials with positive Poisson's ratios. The open-circuit voltage of Auxetic-TENG achieves a four-times improvement compared to conventional contact-separation TENG, highlighting its potential as a wearable self-powered sensor for real-time health monitoring. image