Hierarchical Aluminum Vanadate Microspheres with Structural Water: High-Performance Cathode Materials for Aqueous...

Controlling morphology, adopting metal cations and introducing crystal water are three effective strategies to improve the electrochemical performance of various battery electrodes. However, the effects of simultaneously applying these three strategies to aqueous rechargeable zinc batteries (ARZBs) are rarely demonstrated. Herein, hierarchical H₁₁ Al₂ V₆ O_23.2 (HAVO) microspheres were successfully prepared using a simple hydrothermal method, and used as cathode material for ARZBs. The as-prepared HAVO microspheres exhibited superior electrochemical performance than the dehydrated AlV₃ O₉ (AVO) microspheres, i. e. they have a larger specific capacity of 390.4 mA h g^-1 at 100 mA g^-1 , a better rate capability of 191.4 mA h g^-1 at 5000 mA g^-1 and a higher cycling stability of up to 1000 cycles with a capacity retention of 80.9 %. The excellent electrochemical performance of HAVO is due to the synergistic effects of the shortened ion diffusion distance in primary HAVO nanosheets, the improved electronic conductivity, and structural stability by adopting Al³⁺ into the lattice, the enhanced charge transfer properties and ion diffusion coefficient of the electrode due to the existence of crystal water. Therefore, this work may offer a new route for the design and synthesis of more advanced electrode materials for ARZBs.