4D-printed self-recovered triboelectric nanogenerator for energy harvesting and self-powered sensor

Abstract

Based on the triboelectrification and electrostatic induction, triboelectric nanogenerators (TENGs) have already expanded many applications ranging from ambient mechanical energy harvesting to self-powered sensors. Diverse advanced techniques have been utilized to fabricate various devices to fulfill those applications. To further develop the wide utilization of TENGs, we introduce 4D printing technology to fabricate the transparent self-recovered TENGs, which not only provide excellent self-recoverability of device performance and improve the robustness of device structure, but also open a path to fabricate complicated structure through computer design with no need of any molds. The printed devices have the capabilities of harvesting mechanical energy with maximum output power density of 56 mW/m2 as well as detecting the bending angles of human joints as self-powered sensor. The self-recoverability is originated from shape memory polymer (SMP) under thermal treatment. Therefore, the self-recovered TENGs based on 4D printing technology may offer great potential in energy harvesting and self-powered sensors for human-robot cooperation in sensing and control of robot in need of sophisticated and precise structures.