Green fabrication of double-sided self-supporting triboelectric nanogenerator with high durability for energy harvesting and self-powered sensing

The first double-sided self-supporting triboelectric nanogenerator (DS-TENG) with high durability and output performance is developed. A sustainable and scalable supercritical carbon dioxide (scCO₂) foaming technique is used to fabric porous composite thermoplastic polyurethane (TPU) foams with regular bumps and valleys by embedding a stainless steel mesh (SSM) inside. When packaged using two silicone rubber films, the DS-TENG realizes simultaneous utilization of both sides of the composite foam and effectively prevents the SSM electrode from erosion, which significantly enhances the output performance and durability while maintaining high flexibility. The working mechanism of the DS-TENG is elaborated by manipulating the structure of the composite foam via changing the mesh grid and the foaming conditions. Attributing to the wear resistance of the comprising materials and compact device configuration, the DS-TENG exhibits exceptional durability and long-term stability. Moreover, the DS-TENG demonstrates tremendous potential in self-powered sensing of pressing and bending, monitoring human walking and sitting behaviors, and assisting pugilist training. This work provides a new design of compact self-supporting TENGs with reliable long-term performance and paves a cost-effective approach for green and scale fabrication of TENGs.