A non-contact triboelectric vibration sensor with a spiral floating electrode structure for low-frequency vibration monitoring

High sensitivity at low frequencies is required by many vibration monitoring scenarios, yet commercial piezoelectric vibration sensors often lack adequate sensitivity in this range. This work introduces a novel non-contact triboelectric vibration sensor featuring a spiral floating electrode structure (SFE-TEVS), achieving an impressive sensitivity of 100 V/g, 500 times higher than commercial piezoelectric vibration sensors and operating across a broad frequency range (1-1000 Hz). The non-contact design and integrated structure contribute to durability and maintain stable performance over 300,000 cycles. Additionally, the SFE-TEVS demonstrates excellent acceleration linearity (R2 = 99.95 %) and frequency consistency, both of which are consistent with the results of theoretical analysis. Thus, it was employed to monitor low-frequency active seismic signals and machinery operating states. The SFE-TEVS was further fabricated into a hydrophone for monitoring very-low frequency underwater acoustic waves. It exhibited a sensitivity far superior to the commercial 8105 hydrophone in a 10-100 Hz frequency range, surpassing it by 31.7 dB at 65 Hz, meanwhile exhibiting excellent directivity. The SFE-TEVS combines high sensitivity, broad frequency range, and remarkable durability, showcasing the great potential for active seismic, machinery vibration, and underwater acoustics monitoring, further advancing the application of TENG in these fields.