Longer lifespan for rechargeable zinc-iodine batteries

While rising demand for lithium-ion batteries pushes prices higher, Flinders University experts are working to develop a safe and more sustainable zinc-iodine rechargeable battery.

In their latest study, published in the journal Angewandte Chemie, the research team has designed an aqueous zinc-iodine battery (AZIB) that can be charged and discharged over 60,000 cycles.

“Rechargeable aqueous zinc-iodine batteries are shaping up as a viable alternative to popular lithium-ion batteries for large-scale energy storage and our group is now working with industry to establish a prototyping platform for this alternative battery system,” said associate professor in chemistry Zhongfan Jia, from Flinders University’s College of Science and Engineering.

Iodine is one of the most effective materials for rechargeable batteries, with the potential to store a high amount of energy relative to its weight — around 211 mAh/g (milliampere-hours per gram).

However, one of the biggest challenges with this new battery technology is stopping iodine species from moving to places it shouldn’t inside the unit.

The new battery uses a low-cost organic cyclodextrin-based polymer that helps store and control key chemicals, allowing it to charge quickly while maintaining performance. When fully charged in seven minutes, it can operate at 1.3 to 1.4 volts (V) with a capacity of 200 mAh/g over 8000 cycles, or it can be charged in just three minutes and last for more than 60,000 cycles at 150 mAh/g.

Cyclodextrins are widely used in food, pharmaceutics and cosmetic ingredients. Their unique structure acts like a cage, locking iodine compounds in place and preventing them from disrupting the battery’s operation.

“This system offers a new approach to mitigate polyiodide shuttling by using polymers derived from inexpensive, biodegradable materials, thereby enabling sustainable and long-lasting aqueous zinc-iodine batteries,” Jia said.

Increasing demand and consumption of lithium-ion batteries (LIBs), from electric vehicles to portable electronic devices, have led to resource shortages, costly supply issues and major waste-recycling issues. Australia produces about 3300 tonnes of LIB battery waste a year, which is expected to rise to more than 136,000 tonnes by 2036.

The new batteries rely on zinc metal, a low-cost and widely available metal for which Australia holds the world’s largest known zinc reserves, accounting for 20–28% of the global total.

“As a top global producer and exporter, we can use these zinc resources for safer energy storage, which is important for energy manufacturing in Australia,” said first co-author Shangxu Jiang.

Image credit: iStock.com/sasha85ru