Project leaders Drs Manickam Minakshi and Danielle Meyrick of Murdoch’s School of Chemical and Mathematical Sciences said that they were drawn to using sodium in the battery solution because its chemical properties are similar to lithium.

The battery has excellent potential for large-scale use, including storing energy from wind turbines and solar farms for later feeding into local electricity grids. 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 – according to Dr Minakshi.

“To provide power at non-generation times, excess energy needs to be stored in batteries, but storage technologies now being considered, such as molten salt or molten sulfur, work at high temperatures, making them expensive and impractical,” Dr Minakshi said.

“Ions travel out of the cathode and into the anode to form a current. As an imperfect analogy, you can think of them as mesh filters that ions pass through; we had to find materials with larger gaps in their mesh.”

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Dr Minakshi tested various metals and phosphates, eventually finding success with manganese dioxide as the cathode and a novel olivine sodium phosphate as the anode. The result is a safe, cost-effective battery with high energy density, according to Murdoch.