Advanced organic framework structures tailored for high-efficiency capacitive deionization: from molecular design to performance enhancement
Hao Wang, Yue Zhu, Junfeng Li, Yuquan Li, Yong Liu, Xingtao Xu, Zeqiu Chen, Xinjuan Liu, Likun Pan
Abstract
Freshwater scarcity is becoming an increasingly urgent global challenge that demands immediate attention. Capacitive deionization (CDI) has emerged as an attractive desalination method owing to its straightforward operation, minimal energy consumption, and sustainability. However, the widespread use of CDI is hindered by the limited desalination capacity and inferior cycling stability of carbon-based electrodes. Recently, organic framework materials—including metal–organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks—have garnered increasing interest owing to their high specific surface areas and tunable pore structures, with various design strategies developed to enhance their CDI performance. Nevertheless, a critical gap remains in the systematic understanding and comparative evaluation of these design strategies, which hinders the synergistic development of organic framework materials for CDI. More importantly, the structure-performance relationships of organic framework materials are not yet clearly understood, impeding the rational design of high-performance materials. Therefore, this work aims to provide a comprehensive overview and comparative analysis of the strategies employed to enhance the CDI performance of organic framework materials. Additionally, the structure-performance relationships of these materials are systematically analyzed from the perspective of molecular design. Finally, critical challenges and their associated solutions are discussed to advance the development of high-performance organic framework-based CDI technologies.