Mechanistic Insights of Zn‐Ion Storage in Synergistic Vanadium‐Based Composites

Abstract A novel composite material Na 2 V 6 O 16 ·3H 2 O‐Al x V 2 O 5 (NVO‐AVO) is designed and synthesized for the first time in aqueous zinc ion battery cathode. The electrochemical behavior is elucidated in detail using in situ and ex situ techniques. The NVO‐AVO is simple, inexpensive, and safe to fabricate and contributes to the synergistic effect of orthorhombic Al x V 2 O 5 (AVO) and monoclinic Na 2 V 6 O 16 ·3H 2 O (NVO), the NVO‐AVO composites have fast Zn 2+ kinetics and exhibit good electrochemical properties. At 300 mA g −1 , the specific capacity is as high as 392.5 mA h g −1 , and even more excitingly, NVO‐AVO remains a specific capacity of 160.6 mA h g −1 even after 18 300 cycles at 5000 mA g −1 , which is significantly better than the stability of both NVO and AVO. The distinctive V 3 O 8 layered structure in Na 2 V 6 O 16 ·3H 2 O facilitates the diffusion of Zn 2+ , and structural water located between the V 3 O 8 layers facilitates rapid charge transfer by widening the gallery spacing and supposing more storage sites for Zn 2+ . In addition, Al x V 2 O 5 forms [AlO 6 ] octahedral units that enhance structural stability and play a crucial role in maintaining long‐term cycling stability. This work supports the theoretical basis and technical support for the development and extension studies of new vanadium‐based electrode materials.