Power generation mechanism of carboxyl functionalized graphene oxide based hydroelectric generator

作者：Yile Lu, Haowei Jia, Tianyue Liang, Linghui Meng, Xinren Zhang, Yuan Yu, Bohao Wen, Ziheng Feng, Tao Yin, Peiyuan Guan, Shuo Zhang, Lu Zhou, Yingze Zhou, Caiyun Wang, Dewei Chu · 发表于：Journal of Power Sources · 年份：2025 · DOI：10.1016/j.jpowsour.2025.238484 · 被引用次数：3 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Energy Harvesting in Wireless Networks、Graphene research and applications

Hydrovoltaic energy harvesting, which converts water-solid interactions into electricity, offers a promising route for sustainable and self-powered technologies. Understanding the interaction between water and graphene oxide (GO) at the solid-liquid interface is essential for advancing hydrovoltaic energy conversion. In this study, we designed a symmetric, metal-free hydrovoltaic generator to systematically investigate the underlying mechanism of electricity generation driven by water-GO interactions. To isolate the intrinsic contribution of GO without interference from redox-active electrodes, inert carbon electrodes were used. The surface chemistry of GO was precisely tuned through mixed-gas (O 2 /Ar) plasma treatment, allowing selective enrichment or removal of oxygen-containing functional groups, particularly carboxyl (-COOH) groups. Oxygen-rich plasma treatment is found to enhance GO's surface hydrophilicity and increase the presence of –COOH groups, as evidenced by FTIR, XPS, and contact angle results. Among the treated samples, the optimally functionalized GO achieved an open-circuit voltage exceeding 300 mV and a short-circuit current density above 7 μA cm −2 under deionized water contact. The hydrovoltaic response is driven by water adsorption, -COOH dissociation, electrical-double layer formation, and directional proton migration induced by an evaporation-driven wet-dry gradient. The correlation between surface functionality and output performance confirms the criti...