Murdoch University researchers have developed a water-based sodium-ion battery which they say shows excellent potential for affordable, grid-scale energy storage.

Other storage technologies, such as molten salt or molten sulfur, work at high temperatures, making them expensive to use. The water-based sodium-ion battery provides more affordable low-temperature storage. The battery has the added advantage of being based on abundant sodium, iron and manganese, potentially making green energy storage available and affordable in the developing world.

Sodium was used because its chemical properties are similar to lithium which is used in most portable electronic devices.

According to the project leaders, Drs Manickam Minakshi and Danielle Meyrick, the challenge was to find material for cathodes and anodes capable of accommodating sodium’s ionic size, which is 2.5 times larger than that of lithium.

The researchers eventually succeeded with manganese dioxide as the cathode and a novel olivine sodium phosphate as the anode.

Dr Minakshi said that the result is a safe, cost-effective battery with high energy density.