Special Rubber with Excellent Mechanical Strength and Thermal Stability for Temperature Difference Generator Applications

Thermoelectric generators (TEGs) are capable of converting part of the unreusable light and heat energy into electrical energy, which is an emerging energy harvesting technology. However, the photothermal conversion layer, as a key component of the TEG, is susceptible to mechanical damage and structural damage under the influence of external stress stimuli and high-temperature environments, which affects the stable operation of the TEG. Therefore, it is a great challenge to develop a photothermal conversion layer that combines excellent mechanical properties and thermal stability. This study develops a multistep cross-linking strategy to prepare high-performance elastomers. The composite contains a carboxylated nitrile rubber (XNBR) matrix, hydroxyethyl methacrylate (HEMA) grafts, and dual ZnO nanofillers and carbon black. The fabrication process sequentially integrates grafting, hydrogenation, filler incorporation, and cross-linking. The optimized material demonstrates enhanced mechanical properties with a tensile strength of 8.1 MPa. Its thermal stability is improved, showing an initial decomposition temperature at 393 °C. Subsequently, a rubber-based thermoelectric generator (R-TEG) was assembled, and the R-TEG showed excellent output performance and stability and was able to stably output a voltage of 1.2 V when irradiated with a near-infrared lamp for 400 s; the corresponding power density is 18.375 μW/cm². This study provides a strategy for developing TEGs with strong output performance and stable operation, thus contributing to sustainable energy solutions.