Researchers at Flinders University have engineered a sustainable, high-performance aqueous zinc-iodine battery (AZIB) that could serve as a viable alternative to lithium-ion technology for large-scale energy storage. By utilizing a biodegradable, starch-derived polymer to prevent the degradation typically caused by the “shuttle effect,” the team achieved a remarkable lifespan of over 60,000 charge-discharge cycles. This innovation offers a non-flammable, cost-effective solution that addresses the environmental waste and safety concerns associated with traditional lithium-ion batteries, while simultaneously leveraging Australia’s abundant domestic zinc reserves to support a more secure and sovereign energy storage industry.
The new battery system solves a long-standing technical hurdle known as the “shuttle effect,” where polyiodine species leak through the battery separator, causing performance to decline. To combat this, the research team developed a microscopic cage structure using a cyclodextrin-based polymer derived from starch. This material features a unique design with a hydrophilic exterior and a hydrophobic interior, which effectively traps and releases polyhalides on demand. This breakthrough prevents leakage and allows the battery to maintain an incredibly low degradation rate of just 0.0001% to 0.0003% per cycle.
In terms of performance, the AZIBs demonstrate impressive versatility for grid-scale applications. When charged in seven minutes, the system provides a capacity of 200 mAh/g over 8,000 cycles. By adjusting the target capacity to 150 mAh/g, the battery can achieve a full charge in only three minutes while extending its lifespan to more than 60,000 cycles. Operating at 1.3 to 1.4 volts, these batteries provide a safer, non-flammable alternative to lithium-ion systems, which are currently prone to fire risks and contribute to significant environmental waste.
The economic implications for Australia are substantial. While the nation currently faces challenges regarding lithium processing and supply chain vulnerabilities, it possesses between 20 and 28 percent of the world’s known zinc reserves. By utilizing zinc as an anode, Australia is well-positioned to anchor a domestic energy storage industry. Flinders University is currently collaborating with industry partners to develop a commercial prototyping platform for this technology, as detailed in their findings published in the journal Angewandte Chemie. This shift toward zinc and plant-based polymers could prove pivotal for the future of sustainable energy storage.