Melocanna humilis leaves-inspired droplet electricity generator with hierarchical charge regulation for stable energy harvesting in high-humidity environments

Against the backdrop of pressing global challenges in energy transition and environmental sustainability, droplet-based electricity generator (DEG) have emerged as promising candidates for energy harvesting. However, its output performance under high-humidity conditions has been hampered by moisture-induced charge dissipation. Here, we report a humidity-resistant DEG (HR-DEG) inspired by Melocanna humilis leaves. Specifically, a bio-inspired hierarchical micro/nanostructure with condensation-shedding properties is fabricated by precisely controlling interactions between BTO, PTFE, and PDMS film. This design substantially reduces surface energy, thereby mitigating charge dissipation to ambient moisture and suppressing charge screening effects. Furthermore, the synergistic integration of the polarization-enhancing properties of BTO with the strong electronegativity of PTFE enables hierarchical charge regulation, leading to markedly improved output performance. Experimental results demonstrate that HR-DEG achieves an open-circuit voltage exceeding 230 V, an output charge of 315 nC, and a peak power of 83 μW while retaining approximately 90 % of its full-scale output at 90 % RH. Additionally, the device exhibits excellent moisture resistance after physical and chemical stability tests. Especially, even after more than 15,000 operation cycles and 90 days, HR-DEG still achieves an output of over 190 V. These results highlight the potential for energy harvesting in high humidity and other challenging conditions.