A Sustainable Redox-Flow Battery with an Aluminum-Based, Deep-Eutectic-Solvent Anolyte

Refreshing rechargeable batteries with aluminium and urea

22 December 2017

An aluminium-based electrolyte could pave the way towards cheap, sustainable and high-performance rechargeable batteries.

Energy storage is essential, from rechargeable batteries in phones and electric cars to storing renewable energy for the power grid. Redox flow batteries (RFBs), which store chemical energy in fluids, are a promising option but their anolytes — the conductive fluid, or electrolyte, at the positively charged end of the cell — are made from expensive and potentially toxic ingredients. A team including researchers from the Institute of Functional Nano & Soft Materials at Soochow University made an anolyte by mixing aluminium chloride with urea and a solvent that prevents the fluid reacting to temperature changes. They tested the anolyte in an RFB, and found it could store 165 Watt hours per kilogram, one of the highest energy storage capacity of any RFB to date.

Aluminium is an abundant and non-toxic metal, a cheap, safe and environmentally friendly alternative to lithium in rechargeable batteries.

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References

1. Angewandte Chemie 56, 7454 –7459 (2017). doi: 10.1002/anie.201703399