Wang Chenxing, Duan Peng, Huang Yinpeng, Lu Xulei, Fu Chunqiao, Zhang Yong, Qian Linmao, Yang Tingting
Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, PR China.
Institute of Smart City and Intelligent Transportation, Southwest Jiaotong University, Chengdu, PR China.
Nat Commun. 2025 Jul 16;16(1):6568. doi: 10.1038/s41467-025-61898-5.
Water and ion channels are crucial for moisture energy harvesting, requiring precise pore design for mass transfer control. However, the key challenge lies in managing the localized assembly process of membrane materials to arrange them orderly, forming confined mass transfer pathways and stable solid-liquid interfaces. This is essential for exploring the interrelationship among channel morphological characteristics, mass transfer dynamics, and device power generation performance. This work proposes the use of freeze-assisted salting-out to meticulously construct hydrogel bilayer membranes with micro-meso-macroporous oriented channels and asymmetric charge characteristics. The produced polyvinyl alcohol/MXene hydrogel devices achieved a V × J of 11.4 μW cm (pure hydrovoltaic effect) and 146 μW cm (with active electrodes) at 25 °C, 45%RH, surpassing most moisture-based generators. In addition, the power generation performance is highly consistent with the Hofmeister series, with stronger salting-out effect to obtain more micropores and mesopores, and ice crystal growth can help obtain ordered macropores. It has faster water transport rate, higher ionic conductivity, better ionic selectivity, and stronger channel stability than traditional moisture-based power generation membranes. This relationship between pore tuning from salt ions and device power generation performance provides a design basis for the development of high-performance moisture-based power generators.
水通道和离子通道对于水分能量收集至关重要，需要精确的孔设计来控制传质。然而，关键挑战在于管理膜材料的局部组装过程，使其有序排列，形成受限的传质路径和稳定的固液界面。这对于探索通道形态特征、传质动力学和器件发电性能之间的相互关系至关重要。这项工作提出使用冷冻辅助盐析法精心构建具有微-介-大孔定向通道和不对称电荷特性的水凝胶双层膜。所制备的聚乙烯醇/MXene水凝胶器件在25°C、45%相对湿度下实现了11.4 μW cm的V×J（纯水伏效应）和146 μW cm（带有活性电极），超过了大多数基于水分的发电机。此外，发电性能与霍夫迈斯特序列高度一致，盐析效应越强，获得的微孔和介孔越多，冰晶生长有助于获得有序的大孔。与传统的基于水分的发电膜相比，它具有更快的水传输速率、更高的离子电导率、更好的离子选择性和更强的通道稳定性。盐离子调孔与器件发电性能之间的这种关系为高性能基于水分的发电机的开发提供了设计依据。
