Silane-modified MXene/PVA hydrogel for enhanced streaming vibration potential in high-performance flexible triboelectric nanogenerators

To meet the growing demand for flexible, self-powered, and portable electronic devices—vital for advancing soft robots, electronic skins, and energy-harvesting technologies—we've refined our approach to creating polyvinyl alcohol (PVA) modulating polyethylene glycol (PEG) to facilitate cation movement along polymer chains, significantly boosting the hydrogel's performance in triboelectric nanogenerators (PPh TENG), which is further enhanced by adding with layered Ti3C2 nanosheets, serving as ionic conductors. These nanosheets introduce an efficient electrostatic mechanism known as the streaming vibration potential (SVP), significantly augmenting the device's functionality. Moreover, we used 3-chloropropyltrimethoxysilane (CPTMS) and 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (FOTS) to modify the surface of MXene nanosheets to fabricate Cl-MXene and F-MXene hydrogel TENGs, as named by Cl-MPPh and F-MPPh TENGs, respectively. The SVP effect is enhanced by these modified MXene nanosheets in the hydrogel, which is more substantial than unmodified MXene nanosheets. This is attributed to the higher charge density in the electric double layer formed between the MXene nanosheets and water. The Cl-MPPh and F-MPPh TENGs demonstrate open-circuit voltages of 190 V and 212 V, respectively. Our theoretical calculations show a marked increase in the distribution of electric potential. This increase occurs on both sides of the MXene nanosheets as water molecules move through them. The F-MPPh TENG exhibits exceptional sensitivity to mechanical stimuli, which holds promising potential for integration into motion sensors designed to monitor human body movements, including the bending of elbows and wrists.