Flow-electrode capacitive deionization (FCDI) is an emerging desalination technology for its high desalination efficiency and continuous operation. This study systematically investigated the feasibility of various representative carbon-based materials and their combinations as the flow-electrode with the primary focus on their desalination efficiency and energy efficiency in FCDI. Among individual carbon-based electrode materials, namely activated carbon (AC), carbon fiber (CF), carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and graphene nanoplatelets (GNPs), the nano-scale materials obviously outperformed micron-scale materials. Whereas, the combinations of AC + MWCNTs/GNPs provided superior desalination performance than AC + CB while working as blended flow-electrodes in FCDIs due to the different spatial configurations of three nano-scale particles. Furthermore, CB was tested as the base material in combination with MWCNTs and GNPs respectively. Approximately 110–130% increments in maximum salt adsorption rate were obtained for both blended electrodes compared to individual CB electrodes. The highest SAR_max of 1.59 ± 0.02 μg cm⁻² s⁻¹ was observed in FCDI driven by the CB + GNPs electrode at a content of 1.5/0.5 wt%. Supported by the results of field emission scanning electron microscopy (FESEM) and electrical impedance spectroscopy (EIS), the 2D spatial morphologies of GNPs were able to build similar but more stable “bridges” between base electrode particles (i.e., AC or CB) as CNTs. Its sheet-like structure avoided agglomeration problems and largely promoted the conductivity of the product flow-electrodes.

流电极电容去离子（FCDI）是一种新兴的海水淡化技术，具有脱盐效率高和连续运行等优点。本研究系统地研究了各种代表性碳基材料及其组合作为流电极的可行性，主要关注它们在 FCDI 中的脱盐效率和能源效率。在活性炭（AC）、碳纤维（CF）、炭黑（CB）、多壁碳纳米管（MWCNTs）和石墨烯纳米片（GNPs）等碳基电极材料中，纳米级材料明显优于微米级材料。然而，AC + MWCNTs/GNPs 的组合提供了优于 AC + CB 的脱盐性能，同时由于三种纳米级颗粒的不同空间配置，在 FCDI 中作为混合流电极工作。此外，CB 作为基础材料分别与 MWCNT 和 GNP 结合进行了测试。与单独的 CB 电极相比，两种混合电极的最大盐吸附率增加了大约 110-130%。最高特区在含量为 1.5/0.5 wt% 的 CB + GNPs 电极驱动的 FCDI 中观察到_最大值为 1.59 ± 0.02 μg cm ^-2 s ^{-1 。}在场发射扫描电子显微镜 (FESEM) 和电阻抗谱 (EIS) 结果的支持下，GNP 的二维空间形态能够在基础电极颗粒（即 AC 或 CB）之间建立类似但更稳定的“桥梁”碳纳米管。其片状结构避免了结块问题，并大大提高了产品流电极的导电性。