High-strength MXene sheets through interlayer hydrogen bonding for self-healing flexible pressure sensor

Abstract

MXenes have attracted widespread attention due to their excellent mechanical properties, metal electrical conductivity, and other excellent physical and chemical properties. However, its excellent mechanical properties are often manifested in nanoscale monolayer MXene sheets. Due to the poor van der Waals interactions among the MXene layers during the molding process, MXene films at the macroscopic scale tend to exhibit poor mechanical properties such as brittleness and even fracture. Therefore, when MXenes with excellent electronic properties are used in devices, their ability to resist external damage is often poor, which makes the device performance easily degraded or even failed. We constructed MXene sheet with high mechanical strength via the interlayer hydrogen bonding effect using one-dimensional aramid nanofibers. MXene sheet is used for self-healing flexible pressure sensor, which shows high sensitivity (208.7 kPa−1), fast response time (10 ms) and recovery time (33 ms), excellent cycle stability (45000 cycles), and outstanding self-healing properties. The high-strength MXene sheet with 30 % ANF of the champion sensor exhibits superior tensile strength (65.5 MPa) and toughness (210.9 MJ/m3), which are ∼712 % and ∼ 3347 % of those of pure MXene, respectively. The MXene/ANF based pressure sensor realizes good resistance to complex external damages due to the combined effect of self-healable shell and the robust MXene sensitive layer, thereby meeting the development requirements of future smart wearable electronic devices.