Structural Modification of V2O5 as High-Performance Aqueous Zinc-Ion Battery Cathode

We report the NH 4 + intercalated V 2 O 5 , i.e. (NH 4 ) 2 V 10 O 25 •8H 2 O, with excellent electrochemical performance as cathode in aqueous zinc-ion battery (ZIBs), as compared to V 2 O 5 , Na 5 V 12 O 32 and K 2 V 8 O 21 . This work reveals that the ionic conductivity of Zn 2+ can be enhanced by introducing cations into the V 2 O 5 framework and the vanadium oxygen structural units will be rearranged. Compared to a single layer of vanadium pentoxide consisting solely of VO 5 units, the electrochemical performance of the structural units rearranged vanadates shows a significant improvement. As a result, the obtained (NH 4 ) 2 V 10 O 25 •8H 2 O delivers high discharge capacity (376 mA h g −1 at 0.5 A g −1 ), superior rate capability up to 10 A g −1 , excellent cycling stability (a capacity retention over 93% for 1000 cycles) and high energy density (341 Wh kg −1 ).