A biocompatible, eco-friendly, and high-performance triboelectric nanogenerator based on sepiolite, bentonite, and kaolin decorated chitosan composite film

Recent advancements in triboelectric nanogenerators (TENGs) have primarily focused on improving power conversion and generation efficiency. However, challenges still exist in developing TENGs that are affordable and biocompatible. Chitosan, an abundant natural biopolymer derived from marine crustacean shells, and natural clays offer exciting possibilities for developing cost-effective and biodegradable TENG applications. In this study, we present the development of biocompatible and eco-friendly TENGs by incorporating clay-based compounds as natural fillers into chitosan. To construct chitosan/clay-based biocomposite TENGs, we have introduced sepiolite, bentonite, and kaolin, as natural additives, into the chitosan biopolymer matrix. Decorating chitosan with natural clays improves the triboelectric properties of the TENGs, which in turn enhances the output voltage and significantly boosts the electric power density. Chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin demonstrate open circuit voltages of 863, 996, and 963 V, respectively. Moreover, when compared to pure chitosan-based TENG, the chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin show a maximum output peak power increase of 19, 54.4, and 32.6%, respectively. At 1.1 MΩ load resistance, the maximum peak electric power densities of 20.4, 26.5, and 22.8 W/m² are reached for chitosan-based TENGs with 3 wt% sepiolite, 1 wt% bentonite, and 1 wt% kaolin, respectively. Furthermore, we analyzed the surface potential, morphology, roughness, and dielectric constant of chitosan/clay composites to understand the relationship between them and electrical performance. The results demonstrate that the output performances of the chitosan/clay-based TENGs are quite high. TENGs made of biocompatible materials may not only pave the way for the production of environmentally friendly, cost-effective, and efficient TENGs for self-powered nanosystems and biomedical devices but may also shed light on new technologies utilizing natural materials.