Researchers at RMIT University, along with global industry collaborators, have developed recyclable “water batteries” that address safety concerns associated with traditional lithium-ion batteries.
The team focuses on aqueous metal-ion batteries, utilising water instead of organic electrolytes to prevent the risk of fire or explosions. Lead researcher professor Tianyi Ma highlighted the eco-friendly aspect of their batteries, emphasising the ability to safely disassemble them for materials reuse or recycling.
“What we design and manufacture are called aqueous metal-ion batteries – or we can call them water batteries,” Ma said.
“Addressing end-of-life disposal challenges that consumers, industry and governments globally face with current energy storage technology, our batteries can be safely disassembled and the materials can be reused or recycled.”
According to RMIT, the simplicity of the water battery’s manufacturing process makes mass production feasible, using abundant and less toxic materials like magnesium and zinc.
The team overcame several challenges, including prevent dendrite growth by coating battery parts with a protective layer of bismuth and its oxide.
As a result, the water batteries demonstrated a longer lifespan comparable to commercial lithium-ion batteries, making them suitable for high-speed and intensive real-world applications.
The energy density of the water batteries is closing the gap with lithium-ion technology, with a recent magnesium-ion water battery achieving an energy density of 75 watt-hours per kilogram (Wh kg-1), approaching 30 per cent of the latest Tesla car batteries. The goal is to further increase energy density by developing new nano materials for electrodes.
Professor Ma sees magnesium-ion water batteries as potential replacements for lead-acid batteries in the short term (1-3 years) and lithium-ion batteries in the long term (five to ten years).
“Magnesium is lighter than the alternative metals, including zinc and nickel, has a greater potential energy density and will enable batteries with faster charging times and better capability to support power-hungry devices and applications,” Ma said.
The study, Synergy of dendrites-impeded atomic clusters dissociation and side-reactions suppressed inert interface protection for ultrastable Zn anode, is published in Advanced Materials.
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