Three-dimensional Prussian blue nanoflower as a high-performance sodium storage electrode for water desalination

Abstract

Capacitive deionization (CDI) is considered as a potential water treatment technology to answer the dilemma of fresh water shortage. Currently, many efforts have been exerted to make intercalation material a promising candidate for CDI in order to realize the commercial feasibility. Herein, we report a facile strategy to prepare three-dimensional flowerlike Prussian blue (PB) intercalation material for efficient water desalination. The PB nucleus achieves oriented growth to form a unique six-petal flowerlike structure because of the addition of ethanol. Compared with cubic PB, flowerlike PB with superior inherent properties has more advantages in desalination capacity and cycling stability. The rocking chair desalination cell assembled by symmetrical electrodes of flowerlike PB delivers a high desalination capacity of 101.3 mg/g and maintains more than 93% of the initial capacity after 60 cycles. The enhanced capacity can be attributed to the three-dimensional flowerlike structure of flowerlike PB, which can enlarge the contact area between electrode and electrolyte, improve the delivery and conversion of Na+ ion. Furthermore, the unique flowerlike structure provides sufficient buffer space for crystal deformation, thus enhancing the stability. Therefore, this work proves flowerlike PB is a promising intercalation material for CDI and paves the way for its application in other fields of electrochemistry.