Graphene aerogel-based vibration sensor with high sensitivity and wide frequency response range

Compared with piezoresistive sensors, pressure sensors based on the contact resistance effect are proven to have higher sensitivity and the ability to detect ultra-low pressure, thus attracting extensive research interest in wearable devices and artificial intelligence systems. However, most studies focus on static or low-frequency pressure detection, and there are few reports on high-frequency dynamic pressure detection. Limited by the viscoelasticity of polymers (necessary materials for traditional vibration sensors), the development of vibration sensors with high frequency response remains a great challenge. Here, we report a graphene aerogel-based vibration sensor with higher sensitivity and wider frequency response range (2 Hz–10 kHz) than both conventional piezoresistive and similar sensors. By modulating the microscopic morphology and mechanical properties, the super-elastic graphene aerogels suitable for vibration sensing have been prepared successfully. Meanwhile, the mechanism of the effect of density on the vibration sensor’s sensitivity is studied in detail. On this basis, the sensitivity, signal fidelity and signal-to-noise ratio of the sensor are further improved by optimizing the structure configuration. The developed sensor exhibits remarkable repeatability, excellent stability, high resolution (0.0039 g) and good linearity (non-linearity error < 0.8%) without hysteresis. As demos, the sensor can not only monitor low-frequency physiological signals and motion of the human body, but also respond to the high-frequency vibrations of rotating machines. In addition, the sensor can also detect static pressure. We expect the vibration sensor to meet a wider range of functional needs in wearable devices, smart robots, and industrial equipment.