3D-printed flexible energy harvesting devices designed using non-layered two-dimensional natural tourmaline silicates

Sustainable energy solutions require high-performance and widely available materials, which could be easily engineered/scaled up to the required dimensions. Natural silicates, being environmentally stable and abundantly accessible, emerge as promising candidates for the development of energy devices. Here, we demonstrate the synthesis of two-dimensional (2D), non-layered tourmaline silicates (T-silicates) through an easily scalable liquid-phase exfoliation method. The 2D T-silicate is used to design fabric-based energy harvesting devices and cellulose-based 3D-printed structures for flexible electronics. The 2D T-silicate energy harvesting device, which is made of fabric, generates a voltage of approximately 10 V when it is tapped with a force of approximately 8.8 N at room temperature. At slightly higher temperatures, specifically at 50 degrees C, a small force of only 0.98 N can produce around 9.2 V. The 3D printed device with mesh design also produced similar to 3 V (peak to peak) upon tapping with a finger. The theoretically estimated piezoelectric coefficient was 4.3 x 10-10 C m-2, and the flexoelectric coefficient was 0.3 nC m-2. The study shows that ultrathin T-silicates can be used not only in fabrics but also in 3D printing for energy harvesting applications. This innovative work opens up new possibilities for sustainable energy solutions by combining advanced materials with state-of-the-art fabrication techniques. This paper shows how non-layered naturally occurring tourmaline silicates can be exfoliated into 2D structures for use in fabrics and 3D printed biomedical health monitoring devices.