Diatomaceous Earth and Carbon Nanotubes Toughened Advanced Rubber Composite for Triboelectric Nanogenerator and Sensor Applications

ABSTRACT This research proposes a composite‐type stretchable triboelectric nanogenerator combining diatomaceous earth (DE), conducting carbon nanotubes (CNT), and a styrene‐butadiene rubber (SBR) matrix for small‐scale energy generation and sensor applications. To enhance the mechanical and triboelectric energy harvesting efficiencies of the rubber composites, grape seed oil (GSO) was used as an in situ filler modifier. Mechanical assessments indicate that DE and GSO, in suitable quantities, can improve certain useful mechanical properties, such as fracture strain, fracture toughness, and Young's modulus, compared to the unfilled SBR compound. However, the presence of stronger reinforcing CNT can significantly improve both the mechanical and electrical properties of the rubber composites. Triboelectric energy‐generating behaviors of the rubber composites suggest that DE and CNT‐based hybrid fillers can significantly enhance energy harvesting efficiencies. At an optimum concentration of 40 phr (per 100 g of rubber) DE, 10 phr GSO, and 2 phr CNT in the rubber composite, the best fracture toughness value (10.04 MJ/m 3 ) was observed due to improved filler‐rubber adhesion. The composite also showed robust triboelectric energy harvesting efficiencies, with power efficiency, power density, charge efficiency, and charge density values of 0.6 nW/N, 6.25 mW/m 3 , ~0.9 nC/N, and 8.96 mC/m 3 , respectively, at 2% compressive strain. The composite demonstrated better durability over 5000 cycles without any loss in triboelectric efficiency. This composite was tested for sensing biomechanically stimulating patterns, such as writing on it, and showed excellent similarity and repetition. Additionally, a simple pat on the composite rubber sheet (6 × 5 × 0.1 cm 3 ) can generate a high‐power density of 0.8 W/m 3 .