Morphology-modulation of (NH4)2V4O9 nanostructures for enhanced electrochemical performance as cathode material for aqueous rechargeable zinc ion batteries

Herein, we report a hydrothermal process to prepare controllable morphology (NH4)2V4O9 nanosheets by adjusting the amount of acetic acid. Further, the structure and electrochemical property of the (NH4)2V4O9 nanosheets are systematically investigated. The electrochemical tests show that the performance of (NH4)2V4O9 nanostructures is greatly dependent on the morphology of (NH4)2V4O9 samples as cathode materials for aqueous rechargeable zinc-ion batteries. In particular, the (NH4)2V4O9 nanosheets own better electrochemical performance compared with nanoparticles, which exhibit high reversible capacity (358.0 mAh·g−1 at 0.3 A·g−1), excellent cycle performance (82.2% capacity retention after 5000 cycles at 10 A·g−1) and as well as rate performance. The outstanding electrochemical performance of the as-prepared nanosheets can be assigned to well-regulated morphology. This work creates a new and efficient way to design cathodes for aqueous rechargeable zinc-ion batteries.