Layered MXene/Aramid Composite Film for a Soft and Sensitive Pressure Sensor

In recent years, the two-dimensional material MXene has shown great advantages in the field of wearable electronics and pressure sensors. Toward advanced applications, achieving a conformal pressure sensor with ultrathin thickness and great flexibility through a simple preparation principle, while maintaining its high sensitivity and wide detection range, is still a key challenge for the development of high-performance pressure sensors. Herein, we proposed an optimized mild LiF/HCl etching scheme and successfully achieved a high-concentration (>25 mg/mL) preparation of few-layer Ti3C2Tx MXene. Combining the prepared MXene with an aramid nanofiber (ANF), we designed an ultrathin layered pressure sensor based on an MXene/ANF composite through layer-by-layer suction filtration. The mechanical strength is greatly enhanced by composition with the ANF, while the pure MXene film is fragile. The sensor achieves a high sensitivity of 16.7 kPa-1, wide detection range (>100 kPa), only 10 μm thickness, great flexibility, and up to 10% stretchability, which are greatly beneficial to practical sensors. We demonstrated the wide application perspective of the sensor in human motion monitoring and human-machine interfaces from low pressure (human pulse) to high pressure (push-up).