Urchin-like Spinel MgV2O4 as a Cathode Material for Aqueous Zinc-Ion Batteries

The rechargeable aqueous zinc-ion battery is a promising candidate for energy storage demands owning to its low cost, intrinsic safety, and eco-friendliness. However, existing aqueous zinc-ion batteries are far from achieving the exploration of appreciable cathode materials, because multivalent ions have the strong charge repulsion with host material and inherent sluggish kinetics during charge and discharge process. Herein, we introduce a novel urchin-like magnesium vanadate as cathode material for aqueous zinc-ion battery. Specifically, the battery delivers a high capacity of 272 mAh g-1 at 0.2 A g-1, and excellent long-term cyclic stability with a reversible capacity of 128.9 mAh g-1 even after 500 cycles at 4.0 A g-1. Additionally, the calculated energy density for the MgV2O4 cathode is 171.5 Wh kg-1 at 140.6 W kg-1 power density. These remarkable electrochemical performances are attributed to the crystal structure of urchin-like MgV2O4 with low-valence vanadium, transforming from the order to disorde...