Ultra-lightweight aerogel composites for sound-driven triboelectric nanogenerator

Recent advancements in multifunctional materials have underscored the importance of nanostructured porous aerogels in the development of high-performance triboelectric nanogenerators (TENGs) for diverse applications. The unique nanostructured assembly of aerogels integrates a substantial volume of air within the material, leading to ultra-low density and enhanced electrical insulation properties. In this study, we employed polyvinylidene fluoride (PVDF) and graphene nanoplatelet (GnP) to develop an aerogel with superior triboelectric performance. The abundant dipoles within the PVDF matrix, coupled with the conductive GnP nanoparticles and their interaction with the polymer chains, significantly improved charge transfer throughout the aerogel's skeletal framework. This enhancement was reflected in the aerogel's triboelectric performance, where it effectively powered capacitors representative of low-power electronics, achieving a peak power density of 307.5 mW/ m2. By optimizing the polymer load and physical crosslinker via sol-gel processing, the mechanical cohesiveness and flexibility of the aerogel were enhanced. Leveraging its ultra-low density of 0.25 g/cm3, enhanced triboelectric performance, and mechanical flexibility, a Sound Aerogel-based Sensor TENG (SAS-TENG) was designed. The sensor demonstrated that acoustic stimuli within the 40 dB to 120 dB range provided sufficient force to mobilize the ultra-lightweight aerogel, thereby activating the contact-and-separation mode TENG. The voltage output ranged from 1.05 V to 4.85 V as the acoustic stimuli increased from 40 dB to 120 dB. The SAS-TENG exhibited an impressive specific power output of 15.37 mW/g, highlighting its potential for development of lightweight, self-powered sound sensors in IoT networks.