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

Abstract

MgSO₄ is chosen as an additive to address the capacity fading issue in the rechargeable zinc-ion battery system of Mg_xV₂O₅·nH₂O//ZnSO₄//zinc. Electrolytes with different concentration ratios of ZnSO₄ and MgSO₄ are investigated. The batteries measured in the 1 M ZnSO₄^-1 M MgSO₄ 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.