High Performance Electrolyte for Iron-Ion batteries

Abstract

Aqueous rechargeable batteries have received widespread attention due to their excellent power density, simple manufacturing process, and inexpensive electrolyte. Iron-ion batteries are expected to meet the goals of high safety, low cost, and non-toxicity pursued in the field of rechargeable batteries. However, passivation, parasitic hydrogen evolution reaction (HER), and low electroplating efficiency (50%-70%) limit the improvement of electrochemical performance, which greatly restricts their practical application. In this study, a high-performance electrolyte for iron-ion batteries was prepared, and the effect of zinc chloride (ZnCl₂) additives on inhibiting HER and the improvement of coulomb efficiency in ferrous chloride (FeCl₂) electrolyte was explored. Additionally, the effect of the addition of complexing agents in the electrolyte on the coulomb efficiency of the electrodes was studied. It’s demonstrated that the electrode can still obtain a coulomb efficiency of nearly 100% after 20 hours cycling in the electrolyte containing ZnCl₂ additive and FeCl₂, while in FeCl₂ electrolyte, its coulomb efficiency after 20 hours of cycling is only 65%.