The importance of electrolyte environment during in situ self-transformation for synthesizing V 2 O 5 · n H 2 O.

V 2 O 5 · n H 2 O is a promising cathode material for zinc-ion batteries. One of the synthesis methods of V 2 O 5 · n H 2 O is in situ self-transformation. In this communication, we focus on the influence of the electrolyte environment during in situ self-transformation (from VO 2 to V 2 O 5 · n H 2 O). 2 M ZnSO 4 and 2 M Zn(OTf) 2 were used as different electrolytes to produce VOH-1 and VOH-2. VOH-1 expands in volume along the electric field to form a porous surface structure and shows low crystallinity along the (0 0 1) plane, while VOH-2 exhibits the opposite. These advantages enable the assembled batteries with VOH-1 to maintain excellent cycling performance at a rate of 2 A g -1 with a capacity of 500 mA h g -1 and stable cycling for 1800 cycles.