Smart Energy–Harvesting Coating for Moisture–Droplets Based on Ionic Diodes and Transistor–Like Structures

ABSTRACT The growing demand for distributed sustainable energy solutions has driven innovations in atmospheric moisture and droplet‐enabled electricity generation. This study introduces a dual‐mode moisture‐droplet energy‐harvesting coating (MDEC) that integrates a moisture electricity generator (MEG) and a triboelectric droplet electricity generator (DEG) into a single scalable coating system. By employing hybrid MXene‐bridged graphene oxide (GO) microspheres as the hybrid ink electrode and a fluorocarbon resin dielectric layer, the developed MDEC overcomes the limitations of traditional metal‐based electrodes that cannot be scaled for manufacturing and the inefficiency of single‐energy harvesting schemes in moisture environments. The MEG component achieves a voltage output of 0.85 V at 25% relative humidity through ion concentration gradient diffusion, whereas the DEG component has a peak power density of 36 W m −2 with a short‐circuit current of 301 µA and an open‐circuit voltage of 36.5 V. Modular integration of 360 units enables linear voltage scaling up to 301 V, successfully powering commercial LEDs and charging capacitor devices. This design offers a promising pathway for scalable low‐power electronics and Internet of Things (IoT) applications.