High-performance desalination of three-dimensional nitrogen-doped carbon framework reinforced Prussian blue in capacitive deionization

Prussian blue (PB) and its analogs (PBAs) are emerging as promising intercalation candidates for capacitive deionization (CDI) resulted from their rigid open framework and low-cost synthesis. Nevertheless, PBAs normally have structural deficiencies and low electronic conductivity, which leads to the poor cycling stability and inferior capacity. To address these limitations, the iron-based Prussian blue (FeHCF) is embedded in a three-dimensional nitrogen-doped carbon framework (3DNC) in this work. Due to the highly porous structure, 3DNC can serve as an ideal skeletal structure for the growth of FeHCF cubes. The synergistic effect of both composites is mainly reflected on the electrochemical performance, such as high reversible capacity, better cycling stability. Constructing rocking chair desalination cell, FeHCF@3DNC electrode shows high desalination capacity of 60.5 mg g(-1) and excellent repeatability in the cycle. As for energy consumption, the low consumption of 0.30 x 10(3) Wh/m(3) is superior to other materials. Furthermore, it is verified by XPS of FeHCF@3DNC electrode that Fe3+/Fe2+ couple plays a major role in the desalination and regeneration. These results reveal an efficient route for the selection and design of intercalation electrode materials in CDI.

Automated summary

By embedding iron-based Prussian blue (FeHCF) in a three-dimensional nitrogen-doped carbon framework (3DNC), the synergistic effect of both composites enhances the electrochemical performance for capacitive deionization. The FeHCF@3DNC electrode shows high desalination capacity and excellent cycling stability with lower energy consumption compared to other materials. XPS analysis confirms the major role of Fe3+/Fe2+ couple in the desalination and regeneration processes.