Tailoring electrode material and structure of rocking-chair capacitive deionization for high performance desalination

Abstract

With gradually increasing requirement for freshwater, capacitive deionization (CDI) as a burgeoning desalination technique has gained wide attention due to its merits of easy operation, high desalination efficiency, and environmental friendliness. To enhance the desalination performance of CDI, different CDI architectures are designed, such as membrane CDI, hybrid CDI, flow-electrode CDI, etc. However, these CDI systems have their own drawbacks, such as high cost of membrane, capacity limitation of carbon materials and slurry blockage, which severely limit their practical application. Notably, rocking chair CDI (RCDI) composed of symmetric electrode materials delivers excellent desalination performance due to its special dual chamber structure, which can not only break through the capacity limitations of carbon materials, but also deliver a continuous desalination process. Although RCDI showcases high promise for efficient desalination, few works systematically summarize the advantages and applications of RCDI in desalination field. Herein, this review offers a thorough analysis of RCDI, focusing on its electrode materials, structure designs and desalination applications. Furthermore, the desalination performances of RCDI and other CDI architectures are compared to demonstrate the advantages of RCDI and the prospect of RCDI is elucidated.