Capacitive deionization (CDI) is considered to be one of the most promising desalination technologies for brackish water with low to medium salinity. In practical applications, Faradaic redox reactions occurring in CDI may have both negative and positive effects on CDI performance. In this review, we present an overview of the types and mechanisms of Faradaic reactions in CDI systems including anodic oxidation of carbon electrodes, cathodic reduction of oxygen and Faradaic ion storage and identify their apparent negative and positive effects on water desalination. A variety of strategies including development of novel electrode materials and use of alternative configurations and/or operational modes are proposed for the purpose of mitigation or elimination of the deterioration of electrodes and the formation of byproducts caused by undesired side Faradaic reactions. It is also recognized that Faradaic reactions facilitate a variety of exciting new applications including i) the incorporation of intercalation electrodes to enhance water desalination or to selectively separate certain ions through reversible Faradaic reactions and ii) the use of particular anodic oxidation and cathodic reduction reactions to realize functions such as water disinfection and contaminant removal.

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电容去离子（CDI）中的法拉第反应-问题与可能性：综述

对于中低盐度的微咸水，电容去离子（CDI）被认为是最有前途的脱盐技术之一。在实际应用中，CDI中发生的法拉第氧化还原反应可能会对CDI性能产生负面和正面影响。在这篇综述中，我们概述了CDI系统中法拉第反应的类型和机理，包括碳电极的阳极氧化，氧的阴极还原和法拉第离子存储，并确定了它们对水淡化的明显负面影响和正面影响。为了减轻或消除由不期望的副法拉第反应引起的电极的劣化和副产物的形成，提出了包括开发新型电极材料以及使用替代构造和/或操作模式在内的多种策略。还认识到，法拉第反应促进了各种令人兴奋的新应用，包括：i）嵌入电极的加入以增强水的脱盐性，或通过可逆的法拉第反应选择性地分离某些离子； ii）使用特定的阳极氧化和阴极还原反应实现水消毒和污染物去除等功能。