An insight into the intercalation mechanism of urchin-like aluminum vanadate Nano/microspheres for faradaic deionization

Faradaic deionization (FDI) has been proposed as an effective solution to the desalination. However, developing a cathode material that possesses high desalination efficiency, lower energy consumption and good stability remains a significant challenge. Herein, we prepared urchin-like AlV3O9 (AlVO) microsphere with different crystal structure using hydrothermal process followed calcination as cathode material for capacitive deionization. Among them, lamellar AlVO-350 with interlayer crystalline waters of the hydroxide group exhibit a desalination capacity of 92.97 mg g-1 and notably a better cycling stability due to the synergistic effect of coordinated water charge shielding and hydrogen bonds stabilities on layered structure. On the other hand, the AlVO-550,which has a higher ratio of V5+/V4+, provided a desalination capacity of 101.70 mg g-1. It achieves a charging efficiency of 88.6% and an energy consumption of 0.329 kWh kg -1, which attributed to the high proportion of V5+ in VO slabs, facilitating Na+ intercalated reactions. This work opens up pavement for designing more advanced electrode materials for FDI.

Automated summary

Faradaic deionization (FDI) is an effective method for desalination. This research focuses on developing a cathode material for capacitive deionization with high desalination efficiency and stability. The results show that AlVO-350 with interlayer crystalline waters of the hydroxide group exhibits better desalination capacity and cycling stability, while AlVO-550 with a higher ratio of V5+/V4+ has higher desalination capacity and charging efficiency.