A distinctive conversion mechanism for reversible zinc ion storage

For a long time, in aqueous zinc-ion batteries, the intercalation/extraction chemistry of Zn2+/H+ has been considered as the primary energy storage mechanism in vanadium-based compounds. Herein, we observed an interesting phase transition of V2O3 to V2O5 center dot 3H(2)O under high-voltage conditions. The reconstructed phase (V2O5 center dot 3H(2)O) displays an improved specific capacity of 472.4 mA h g(-1), about 5 times larger than that of the original compound (V2O3). What's more, the electrode exhibits a highly reversible conversion reaction between V2O5 center dot 3H(2)O and Zn3V2O7(OH)(2)center dot 2H(2)O (ZVO) during the charge/discharge process, showing an excellent rate capability and cycling stability. The findings also confirm the electrochemical activity of ZVO, which has generally been considered to be an inactive by-product. This energy storage mechanism, different from the previously reported intercalation chemistry, offers a new insight to understand the electrochemical behavior of V-based electrode materials.

Automated summary

Under high-voltage conditions, there is a phase transition in vanadium-based compounds, leading to an improved specific capacity and excellent rate capability and cycling stability. This finding challenges the previously reported intercalation chemistry and provides new insights into the electrochemical behavior of V-based electrode materials.