Sulfite modified and ammonium ion intercalated vanadium hydrate with enhanced redox kinetics for aqueous zinc ion batteries

A new synergetic strategy is performed by sulfite modification and pre-intercalating ammonium ion into vanadium hydrate (S-NVOH) to boost the Zn2+ redox kinetics for aqueous zinc ion batteries (ZIBs). S-NVOH constructs O–S–O bond as SO32- by sulfite modification both in the interlayers and edge of VOH, boosting the multivalent transform of V5+ in VOH by regulation charge distribution of V–O lattice. Additionally, pre-intercalated NH4+ in the VOH able to efficiently pillars and stabilizes the layer structure when cycling. Meanwhile, CV curves and Tafel curves analyses confirm that S-NVOH obtain larger exchange current densities and lower reaction barriers during the Zn2+ redox process. Thus, the S–NVOH obtains an impressive specific capacity of 108 mAh g−1 at 2A g−1 at low temperature (−15 °C) with capacity retention of 91% after 1000 cycles. This kind of synergetic strategy in vanadium compounds provide a broadly applicable approach for improving the electrochemical performance in a range of oxide-based materials for aqueous ZIBs.