Reversible (De)Intercalation of Hydrated Zn²⁺ in Mg²⁺‐Stabilized V₂O₅ Nanobelts with High Areal Capacity

Abstract

Abstract The rechargeable aqueous zinc ion battery (ZIB) is regarded as one of the most promising candidates for large‐scale energy storage applications due to its low‐cost and eco‐friendly properties. However, the development of a suitable cathode operating with high areal capacity and uncovering the relevant reaction mechanisms remain challenging. Herein, the application of Mg 0.26 V 2 O 5 ·0.73H 2 O (MVO) nanobelts as a ZIB cathode is demonstrated. In situ FT‐IR reveals the shift of OH stretching from 3350 cm −1 to 3200 cm −1 , corresponding to the hydration shell of Zn 2+ , while in situ Raman suggests the interlayer charges creening effect, which would boost the intercalation of hydrated Zn 2+ . Density function theory reveals that the hydrated Zn 2+ can lower the Coulombic repulsion at the electrode‐electrolyte interface and circumvents the desolvation penalty of hydrated Zn 2+ during the (de)intercalation process. Additionally, excellent structure stability and large interlayer spacing guarantee the highly reversible (de)intercalation of hydrated Zn 2+ . Therefore, the MVO nanobelts exhibit a high areal capacity of 2.12 mAh cm −2 at 0.05 A g −1 , outstanding cycling stability of 2500 cycles at 10 A g −1 with a mass loading of 5 mg cm −2 . It is believed that the use of hydrated intercalation charge carriers will boost further studies in other multivalent rechargeable batteries.