Enhanced Piezoelectric\nNanogenerator Based on Tridoped\nGraphene and Ti<sub>3</sub>CNT<sub><i>x</i></sub> MXene\nQuasi-3D Heterostructure

The demand for self-powered wearables is surging, as\nconsumers\nseek convenience and portability. Energy-harvesting technologies,\nespecially piezoelectric nanogenerators (PENGs), which convert mechanical\nenergy to electrical energy, hold promise for harvesting human motion\nenergy. Hence, ongoing research aims to enhance the output power efficiency\nand integrate nanogenerators with flexible materials. This involves\nmaterial innovation to boost PENG performance, optimizing structure\nfor flexibility, and improving manufacturing for scalable and cost-effective\nproduction. In this study, heterostructure nanofiller based on interfacial\ninteraction was formed by mixing nitrogen, sulfur, and phosphorus\ntridoped graphene (NSPG) and Ti<sub>3</sub>CNT<sub><i>x</i></sub> MXene in an appropriate ratio, which produces a synergistic\nenhancement effect in the PENG’s electrical output performance.\nAccording to X-ray photoelectron spectroscopy (XPS), Raman spectroscopy,\nX-ray diffractometer (XRD), and Fourier transform infrared spectroscopy\n(FTIR) chemical characterization analysis, it is proposed that the\nexcellent conductivity and rich surface functional groups of these\ntwo-dimensional materials can effectively provide heterointerfaces\nto form a quasi-three-dimensional heterostructure and improve the\ninteraction between the fillers and polymer matrix, promoting the\nelectroactive β-phase, and consequently enhancing the output\npower density of PENG. NSPG and Ti<sub>3</sub>CNT<sub><i>x</i></sub>, with their remarkable electronic and chemical properties,\nwere prepared using an environmentally friendly electrochemical exfoliation\nmethod. The short-circuit current of PENG can be improved to 1.48\nμA, and the open-circuit voltage can be increased to 14.6 V,\n5-fold compared to pure PVDF, and the output power density, <i>P</i><sub><i>A</i></sub>, reaches 2.2 μW/cm<sup>2</sup>. When attached to different parts of the human body, the\nPENG can practically produce electrical signals, which can be rectified\nusing a full-wave bridge rectifier and used to charge a capacitor\nand light up LEDs. This study establishes a robust connection between\nmultifaceted heterostructures and flexible wearable energy harvesters,\noffering promising prospects for advancing flexible, sensitive, and\nself-powered electronics.