Bifunctional Electrolyte Additives Modified Zinc Anode and Cathode

Aqueous zinc-ion batteries have garnered significant attention due to their high safety, cost-effectiveness, and environmental sustainability. However, the performance of the zinc anode is considerably compromised by hydrogen evolution, corrosion, and structural degradation of the cathode. This article provides a detailed discussion of a mixture comprising ZnSO₄, Zn(OTf)₂, and NH₄Cl as electrolytes in zinc-ion batteries. The incorporation of additives such as Zn(OTf)₂ and NH₄Cl not only facilitates the effective formation of a solid-electrolyte interphase containing ZnF₂ and Zn₃N₂ but also mitigates the hydrolysis of the cathode material NH₄V₄O₁₀. Symmetric batteries assembled with bifunctional additives as anodes can achieve a low current density of 1 mA cm^-2 for over 900 h and sustain a higher current density of 5 mA cm^-2 for more than 570 h. Furthermore, the NH₄V₄O₁₀//Zn full battery utilizing bifunctional additives maintains a Coulombic efficiency rate of up to 99.99% after 2000 cycles at a current density of 1 A g^-1. This bifunctional additive is anticipated to play an increasingly pivotal role in practical applications and advanced aqueous-based zinc-ion battery technology.