MXene/rGO/PS spheres multiple physical networks as high-performance pressure sensor

Abstract

Flexible wearable sensors can quantify and visualize the pressure, thus play important roles in practical applications such as medical monitoring, robotics, artificial skin, etc. High-porosity aerogel has excellent application potential in pressure sensor. However, aerogel is prone to irreversible deformation under long-term cycling pressure, which affects the performance of the sensor. How to balance high sensitivity and good cycle stability requires careful design of sensitive components. We propose a strategy to introduce the aerogel structure into the tiny sponge network, which greatly relieves the irreversible deformation and improves the long-cycle stability. A piezoresistive sponge (MGP-sponge) composed of triple morphological networks (MXene/rGO aerogel, PS spheres, and sponge) is obtained by electrostatic self-assembly, freeze-drying, and annealing. By filling the fragile MXene/rGO aerogel into sponge, the sensor could maintain more than 90% of initial sensitivity (224 kPa⁻¹) after 15,000 cycles. It has the advantages of fast response time (63 ms), sensing bending extent, etc. The working mechanism of the MGP-sponge is revealed by in situ FIB-SEM and first-principles calculations. MGP-sponge sensor performs excellently during various applications such as monitoring human activities, differentiating weights on a 2D array, controlling brightness of a LED sign, sensing manipulator finger motion, etc.