Triboelectric nanogenerator metamaterials for joint structural vibration mitigation and self-powered structure monitoring

A metamaterial-inspired triboelectric nanogenerator (META-TENG) is proposed in this work to simultaneously realize vibration suppression and energy harvesting. The compact META-TENG can generate low frequency local resonant phenomenon and significantly reduce the incident vibration at the low-frequency band. A planar spring is created, which guarantees low-frequency resonance and a sufficient triboelectric contact surface within a small-scale device. The bandgap property of the proposed metamaterial is then calculated using the finite element method and corresponds well with the experimental measurement results. To fabricate the TENG, fluorinated ethylene propylene (FEP) film and Ecoflex are employed as the negative and positive triboelectric materials, respectively. It is found that the introduction of multi-walled carbon nanotubes (MWCNTs) into Ecoflex is favorable for enhancing the META-TENG’s output performance, increasing the output voltage by almost three times. The charge density of the TENG can reach up to 453.1μC/m2under 5 N sinuous excitation. The periodic META-TENG configuration also exhibits satisfying vibration suppression performance, where the vibration amplitude of an aluminum plate integrating four META-TENGs is minimized by up to 87 %. The harvested energy from the META-TENG array enables an accelerometer and Bluetooth module to work in wireless mode, making the whole system achieve self-powered vibration monitoring.