Regulation of lamellar structure of vanadium oxide via polyaniline intercalation for high-performance aqueous zinc-ion battery

According to the intercalation mechanism, an ordered modulation of channel structures of metal oxides is crucial to reversibly accumulate large zinc ions with high surface charge density for improving zinc-ion battery performance. However, the irreversible structure-transition commonly results in serious performance decay. Herein, polyanilines are in situ intercalated into the layered vanadium oxide in order to enlarge the lamellar spacing for enhancing the battery performance. With enlarged lattice spacing, the polyaniline intercalated vanadium oxide (PIVO) coupled with a Zn electrode exhibit a large specific capacity of 372 mAh g −1 and good cycling stability. More importantly, in situ characterization results reveal that PIVO allows the accumulation of additional zinc ions without obvious phase transformation and the conjugated polymeric chains enable the structure flexibility in the confined layer space to relieve the intercalation stress for improving cycling stability. Additionally, findings from the in situ infrared spectroscopy measurements elucidate the charge storage mechanism of the battery. Reversible doping processes of polyaniline molecules in vanadium oxide allow the involvement of multiple ions in the charge storage process, improving battery performance. Uncovering the origin of improved charge storage mechanisms is of importance in rationally designing advanced materials with unique organic–inorganic features for high-performance zinc-ion batteries