Dual-Ion Electrochemical Deionization System with Binder-Free Aerogel Electrodes.

Abstract

Desalination devices such as capacitive deionization (CDI) have been developed for many years as an approach to relief freshwater shortage. However, due to the limitation of physical adsorption capacity of CDI, the salt removal capacity is unable to reach high value. To enhance the desalination capacity effectively, battery materials are employed to fabricate a dual-ion electrochemical deionization (DEDI) device. Herein, a binder-free DEDI system with two free-standing aerogel electrodes is reported. A Na3 V2 (PO4 )3 /graphene hybrid aerogel is used as sodium electrode and a AgCl/graphene hybrid aerogel is used as chloride electrode. With electric current passing through, sodium and chloride ions are released or absorbed by two aerogel electrodes. This system achieves super high desalination capacity, excellent cycling stability, and rapid desalination rate. The desalination capacity is as high as 107.5 mg g-1 after 50 cycles with the current density of 100 mA g-1 . The outstanding desalination performance of this system shows a synergistic effect of combining battery materials with graphene for deionization and promises a new potential alternative of future desalination design.