Revolutionary Cathode Chemistry Reduces Self-Discharge in Large-Scale Zinc-Iodine Batteries

A research team from the University of Adelaide has delved into the formula driving aqueous zinc-iodine batteries, uncovering a method to enhance their performance.

Rechargeable aqueous zinc batteries are emerging as potential alternatives to large lithium-ion energy storage systems due to their cost-effectiveness, reasonable density, and high safety standards.

Nevertheless, the traditional hosts for iodine cathodes often exhibit sluggish reactions and poor electrochemical reproducibility, prompting Professor Shizhang Qiao and his team from the School of Chemical Engineering to introduce ferrocene into the cathodes.

Their discoveries were detailed in a publication in the prestigious journal Nature Chemistry.

“The conversion of iodine in aqueous zinc-iodine batteries involves the polyiodides shuttle effect, whereas the conversion of ferrocene, an organometallic compound, can precipitate the polyiodides, resulting in low self-discharge,” explained Professor Qiao, who also serves as the Director of the Center for Materials in Energy and Catalysis.

“Given that ferrocene comprises inexpensive elements, it offers scalability advantages and potentially reduced costs for large-scale production.”

“Simulation outcomes indicate that its incorporation reduces the overall battery cost by 9% compared to scenarios without ferrocene.”

Professor Qiao highlighted that the use of ferrocene effectively eliminates the shuttle effect, a common issue in zinc-iodine batteries, where intermediate polyiodides dissolve in the electrolyte and shuttle between the cathode and anode.

“Not only does the inclusion of ferrocene enhance energy density, but it also reduces costs, making this combination a practical, cost-effective, and scalable approach to advancing aqueous zinc-iodine battery technologies,” Professor Qiao added.

“Our results also demonstrate that the active mass in the cathode can reach 88%, minimizing the capacity loss associated with inactive hosts.”