Integrating battery and capacitive materials for efficient sodium and chloride capture

Capacitive deionization (CDI) has been considered as a novel technology to relieve freshwater shortages. However, due to the limited physical adsorption capacity, the salt removal capacity remains low. To enhance the desalination capacity, battery type, and capacitive materials are employed to fabricate a dual-ion electrochemical deionization (DEDI) device. Herein, a Prussian blue/carbon framework (PB/CF) and BiOCl/CF were prepared by in situ conversion with a MOF-derived carbon framework as the precursor. A PB/CF composite was used as the sodium electrode, and BiOCl/CF was used as the chloride electrode. This system achieved high desalination capacity, excellent cycling stability, and rapid desalination. The maximum desalination capacity was 163 mg g(-1) at 100 mA g(-1), and the desalination rate was 0.631 mg g(-1) s(-1) at a high current density of 1000 mA g(-1). The outstanding desalination performance of this system arose from the synergistic effect of combining battery materials with a carbon framework for deionization and offers potential for future desalination designs.