Manganese-ions and polyaniline co-intercalation into vanadium oxide for stable zinc-ion batteries

Hydrated vanadates are promising layered cathodes for aqueous zinc-ion batteries. However, repeatedly intercalation/deintercalation of Zn2+ leads to structural instability, thus resulting in poor capacity and cyclic degradation. In this study, manganese-ions (Mn2+) and polyaniline are co-inserted into vanadium pentoxide (MnVO-PANI), which expands the interplanar spacing of vanadium pentoxide to 13.6 Å. Moreover, the synergistic pillar effect of Mn2+ and polyaniline enhances the electron and ion transfer kinetics. As a result, MnVO-PANI exhibits a high capacity of 462 mAh g−1 and excellent cycling stability. Even after 10,000 cycles at the current density of 5 A g−1, the MnVO-PANI cathode still displays a high capacity retention rate of 85%. These results suggest that synergistic insertion is an effective strategy to develop high-performance cathodes for aqueous zinc-ion batteries.