Rechargeable Aqueous Zinc-Ion Batteries in MgSO4/ZnSO4 Hybrid Electrolytes

MgSO 4 is chosen as an additive to address the capacity fading issue in the rechargeable zinc-ion battery system of Mg x V 2 O 5 ·nH 2 O//ZnSO 4 //zinc. Electrolytes with different concentration ratios of ZnSO 4 and MgSO 4 are investigated. The batteries measured in the 1 M ZnSO 4 −1 M MgSO 4 electrolyte outplay other competitors, which deliver a high specific capacity of 374 mAh g −1 at a current density of 100 mA g −1 and exhibit a competitive rate performance with the reversible capacity of 175 mAh g −1 at 5 A g −1 . This study provides a promising route to improve the performance of vanadium-based cathodes for aqueous zinc-ion batteries with electrolyte optimization in cost-effective electrolytes.