A Zn(ClO₄)₂ Supporting Material for Highly Reversible Zinc-Bromine Electrolytes

In the case of a conventional zinc bromide electrolyte solution using zinc chloride as additive, an undesirable reaction occurs. In this reaction, complex anions form between zinc and the chloride ions during charging and discharging. To overcome this problem, this paper describes an excellent electrolyte solution using zinc per-chlorate as the additive, resulting in a highly stable and reversible reaction in zinc-bromine flow cells. To show the effectiveness of the proposed solution, electrochemical analyses are carried out using cyclic voltammetry, a miniature zinc-bromine flow cell, and scanning electron microscopy. The solution is then compared with the conventional electrolyte solution using zinc chloride as the supporting material. Experimental results show that use of the zinc perchlorate additive increases the rate of zinc dissolution by improving the reaction rate of bromine in the catholyte half-cell. Consequently, this arrangement allows a highly stable operation for improving the current efficiency of zinc-bromine flow batteries.