Improvement of structural stability of cathode by manganese additive in electrolyte for zinc-ion batteries

Zinc-ion batteries (ZIBs) are considered a candidate for lithium-ion batteries owing to their low cost, eco-friendly nature, and high safety level. In particular, their energy density is high because of a two-electron transfer mechanism involving Zn ions. However, ZIBs have the demerits of low-rate capability and poor cycling life because of the dissolution of Mn in the electrolyte during charging and discharging, which prevents the high potential of ZIBs from being effectively utilized. In this study, a manganese sulfate (MnSO₄) additive was introduced in the electrolyte to overcome these drawbacks. A ZIB with such an electrolyte exhibited stable capacity behavior and high cycling stability. Furthermore, the fabricated ZIBs showed a specific capacity of 289 mAh g⁻¹ at a current density of 0.3 A g⁻¹, improved rate-performance of 116 mAh g⁻¹ at a current density of 2.0 A g⁻¹, and excellent long-term stability of 72% for 200 cycles at a current density of 1.0 A g⁻¹. These findings indicate that the use of the aforementioned additive is a promising for enhancing the electrochemical performance of manganese-based cathodes in electrolyte-optimized next-generation ZIBs.