Versatile energy harvesting and self-powered sensors based on the integration of triboelectric nanogenerators and functional polymers

Abstract

As an emerging technology to convert ambient energy into electricity, triboelectric nanogenerator (TENG) has attracted extensive attentions to cope with energy and environmental crisis, and meet the development requirement of emerging electronics. However, during the process of mechanical energy harvesting and converting, the TENG has to suffer from frequent and long-term mechanical impacts which will inevitably lead to the material and device failure, generating a series of problems, such as the degradation of performance, the loss of life-span, and the generation of electronics waste. In this thesis, we illustrate three strategies in terms of employed polymer materials to resist the negative influence of mechanical impacts on device application. Firstly, we develop a magnetic-assisted noncontact TENG to reduce the mechanical damage of external force toward the device. After introducing the magnetic response polymer composite into the TENG, the direct contact between device and external mechanical stimuli in traditional TENGs can be avoided and replaced by the remotely interaction under magnetic field mediation, which therefore decays the device degradation and failure. The prapared noncontact TENG is further integrated with wind/water blades to enable the wind and water energy harvesting. Secondly, by employing healable polymers and magnetic electrodes into the TENG, we fabricate the self-healing TENG possessing a capability to restore its performance once mechanical damage has occurred. Attributed to the mechanical healability of healable polymers and the conductive healability of magnetic electrodes, the healing efficiency in electric output of device can reach up to above 95 % after the 5th breakage-healing cycle. Additionally, the presented TENG shows shape-tailorability, which enables the device to change its shape to match with various mechanical stimuli. This maximizes the effective contact area of device and further improves the device's performance. Thirdly, we demonstrate an environmental-friendly TENG based on hydrogel to reduce the pollution of electronics waste caused by mechanical broken devices. The hemisphere-shaped Hydrogel-TENG can generate an instantaneous peak output power of 2 mW driven by periodical pressure. The integrated tube-shaped Hydrogel-TENG can harvest mechanical energy from various human motions, including bending, twisting and stretching, and serve as self-powered human motion sensors. The utilized Polyvinyl Alcohol hydrogel shows recyclability to benefit the fabrication of renewable TENG. The open-circuit voltage of renewed hydrogel-TENG can arrive at 92% of the pristine value. This research integrates the TENG and functional polymers and offers feasible concepts and strategies benefiting the development of future mechanical energy harvesters and self-powered sensors with improved robustness, reliability, and sustainability.