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).