Design of Moisture-Enabled Electric Generators Utilizing sp- and sp²-Hybridized Two-Dimensional Carbon Materials: A Minireview and Perspectives

A moisture-enabled electric generator (MEG), as an emerging green energy collection technique, utilizes nanomaterials, such as the most typical two-dimensional (2D) carbon-based materials, to interact with ubiquitous environmental humidity, directly generating electricity. In a 2D carbon-based MEG, functionalized graphene and graphdiyne (GDY) stand out due to their perfect hexagonal symmetry and unique combination of semiconductor behavior, characterized by hybridization of sp and sp² carbon atoms. Researchers are particularly interested in the potential of these materials as moisture-absorbing agents to enhance MEG efficiency and regulate electricity generation performance. This minireview summarizes the impact of factors such as morphology control of carbon-based materials, like graphene and GDY, methods of moisture supply, and electrode design on MEG performance. Subsequently, it discusses MEG applications in fields such as sensing, energy supply, and wearable electronics. Finally, it analyzes the challenges facing MEG development and outlines prospects.