New zinc-iodine battery retains 99.8% capacity after 500 cycles

Scientists at the University of Adelaide in Australia have developed a novel dry electrode technology for zinc-iodine batteries that significantly enhances their performance and stability. This breakthrough involves mixing active materials as dry powders and rolling them into thick, self-supporting electrodes, combined with adding 1,3,5-trioxane to the electrolyte. This chemical induces the formation of a flexible protective film on the zinc anode during charging, preventing dendrite growth—needle-like structures that can cause short circuits. The new electrodes achieve a record-high active material loading of 100 mg/cm², resulting in pouch cells retaining 88.6% capacity after 750 cycles and coin cells maintaining 99.8% capacity after 500 cycles. Zinc-iodine batteries are considered safer, more sustainable, and cost-effective alternatives to lithium-ion batteries for large-scale and grid energy storage, but have historically lagged in performance. This innovation addresses those limitations by reducing iodine leakage, minimizing self-discharge, and extending cycle life