Capacitive deionization (CDI) is an emerging desalination technology for effective removal of ionic species from aqueous solutions. Compared to conventional CDI, which is based on carbon electrodes and struggles with high salinity streams due to a limited salt removal capacity by ion electrosorption and excessive co‐ion expulsion, the emerging Faradaic electrodes provide unique opportunities to upgrade the CDI performance, i.e., achieving much higher salt removal capacities and energy‐efficient desalination for high salinity streams, due to the Faradaic reaction for ion capture. This article presents a comprehensive overview on the current developments of Faradaic electrode materials for CDI. Here, the fundamentals of Faradaic electrode‐based CDI are first introduced in detail, including novel CDI cell architectures, key CDI performance metrics, ion capture mechanisms, and the design principles of Faradaic electrode materials. Three main categories of Faradaic electrode materials are summarized and discussed regarding their crystal structure, physicochemical characteristics, and desalination performance. In particular, the ion capture mechanisms in Faradaic electrode materials are highlighted to obtain a better understanding of the CDI process. Moreover, novel tailored applications, including selective ion removal and contaminant removal, are specifically introduced. Finally, the remaining challenges and research directions are also outlined to provide guidelines for future research.

中文翻译：

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法拉第电极开启电容去离子新时代

电容去离子（CDI）是一种新兴的海水淡化技术，可有效去除水溶液中的离子物质。传统的 CDI 基于碳电极，由于离子电吸附的除盐能力有限和过多的共离子排出而难以应对高盐度流，与传统的 CDI 相比，新兴的法拉第电极提供了升级 CDI 性能的独特机会，即实现由于离子捕获的法拉第反应，高盐度流具有更高的除盐能力和节能脱盐能力。本文全面概述了 CDI 法拉第电极材料的当前发展。在这里，首先详细介绍了基于法拉第电极的 CDI 的基本原理，包括新颖的 CDI 电池架构、关键的 CDI 性能指标、离子捕获机制以及法拉第电极材料的设计原理。从晶体结构、物理化学特性和海水淡化性能方面总结和讨论了法拉第电极材料的三大类。特别强调了法拉第电极材料中的离子捕获机制，以便更好地了解 CDI 过程。此外，还特别介绍了新颖的定制应用，包括选择性离子去除和污染物去除。最后，还概述了剩余的挑战和研究方向，为未来的研究提供指导。