Tailoring nanostructured MXene to adjust its dispersibility in conductive hydrogel for self-powered sensors

MXenes are ideal conductive fillers to construct conductive routes for hydrogel-based flexible sensors owing to their great metallic conductivity, hydrophilicity, and high specific surface area. However, their high tendency to aggregate in sol solution severely limited the performance of the resultant hydrogels. Therefore, to enhance the performance of MXene-filled composite hydrogels, we proposed an oxidization method to tailor the nanostructure of MXene to improve the conductivity, transparency, mechanical properties, and sensitivity of the composite hydrogels. Meanwhile, it is noted that the conductivity of the hydrogel significantly affected the output performance of hydrogel-based triboelectric nanogenerator (H-TENG). The polyacrylamide/oxidized MXene (POM) hydrogel-based TENG with the highest output performance was assembled for self-powered sensing and energy harvesting, which demonstrated great reliability and durability with a maximum open circuit voltage of 243 V and a peak power density of 2.38 W/m2. Moreover, the relationship model between the conductivity of the hydrogel and the output performance of the H-TENG was successfully proposed based on the performance of the developed H-TENGs. Therefore, this work shed lights for reasonable design of H-TENGs with high output performance.