Unipolar Solution Flow in Calcium–Organic Frameworks for Seawater-Evaporation-Induced Electricity Generation
Zhengyun Wang, Yuchen Huang, Tiansui Zhang, Kunqi Xu, Xiaoling Liu, Airong Zhang, You Xu, Xue Zhou, Jiawei Dai, Zhineng Jiang, Guoan Zhang, Hongfang Liu, Bao Yu Xia
Abstract
Seawater-flow- and -evaporation-induced electricity generation holds significant promise in advancing next-generation sustainable energy technologies. This method relies on the electrokinetic effect but faces substantial limitations when operating in a highly ion-concentrated environment, for example, natural seawater. We present herein a novel solution using calcium-based metal–organic frameworks (MOFs, C 12 H 6 Ca 2 O 19 ·2H 2 O) for seawater-evaporation-induced electricity generation. Remarkably, Ca-MOFs show an open-circuit voltage of 0.4 V and a short-circuit current of 14 μA when immersed in seawater under natural conditions. Our experiments and simulations revealed that sodium (Na) ions selectively transport within sub-nanochannels of these synthetic superhydrophilic MOFs. This selective ion transport engenders a unipolar solution flow, which drives the electricity generation behavior in seawater. This work not only showcases an effective Ca–MOF for electricity generation through seawater flow/evaporation but also contributes significantly to our understanding of water-driven energy harvesting technologies and their potential applications beyond this specific context.