From kinetic to electric: The art of hydrogel and MXene nanogenerators in power harvesting

The increasing demand for battery-less systems in electronic devices highlights the urgent need for eco-friendly solutions that address significant health and environmental concerns. This review examines the advanced concept of triboelectric nanogenerators (TENGs), which are innovative systems designed to convert mechanical motion into electrical energy. We delve into the mechanisms and real-world applications associated with TENGs, focusing on cutting-edge materials, including hydrogels and MXenes. To thoroughly understand the working modes, structure-property relationships, and the energy conversion process in TENGs, we critically analyze their operational logic. This review presents an insightful discussion on the potential of hydrogels and MXenes for energy harvesting, particularly in terms of output power density and the comparative effectiveness of various energy harvesting methods. The importance of improving key aspects of TENGs, including achieving high power density, enhancing electrical energy output efficiency, ensuring mechanical stability, and increasing reusability, is discussed in the context of various applications, such as motion detection, humidity sensing, target analysis, agriculture, and electromagnetic shielding. Perspectives on improving the conversion of kinetic energy into electricity and addressing current challenges are presented to pave the way for future sustainable and efficient energy solutions.