NH3 modified β-Na0.33V2O5 with high capacity for aqueous zinc ion battery cathode

Abstract

Vanadium-based materials with high capacity and stability are needed to promote aqueous zinc ion batteries in large-scale energy storage. NH3 modified β-Na0.33V2O5 is prepared by a facile hydrothermal method and subsequent calcination. The NH3 modification mechanism of β-Na0.33V2O5 is proposed, which includes forming vacancies, structural defects and V-O-N bonds after escaping most ammonia molecules from β-Na0.33V2O5’s framework, and retaining a small part of ammonia molecules in its structure. In the Zn/β-Na0.33V2O5 battery system, the β-Na0.33V2O5 delivers a high capacity of 430 mAh g−1 at 200 mA g−1 and good structural stability. After 50th cycles at 200 mA g−1, the β-Na0.33V2O5 modified by NH3 under N2 atmosphere possesses a lower Warburg coefficient of 19.90 Ωcm2s−0.5 than 29.3 Ωcm2s−0.5 of β-Na0.33V2O5 without modification. The rigid β-Na0.33V2O5 is opened by small NH3 molecules, which provides new horizons for optimizing tunneled vanadium-based materials for aqueous zinc ion batteries.