Researchers at Murdoch University in Perth, Western Australia are developing water-based sodium-ion battery.
The concept of using salts for energy storage is nothing new, with molten salt batteries already rolled out in a number of solar farms; including the world’s first baseload solar generation facility in Spain.
However, as great as the technology is, it does have some drawbacks says Dr Manickam Minakshi of Murdoch’s School of Chemical and Mathematical Sciences.
“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 says a water-based sodium-ion battery he and Dr Danielle Meyrickare developing has shown excellent potential for affordable, low-temperature storage.
A major challenge for the researchers was finding suitable material for cathodes and anodes capable of accommodating sodium’s ionic size - 2.5 times greater than that of lithium.
“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,” Dr Minakshi said.
Dr. Minakshi eventually found success with manganese dioxide as the cathode and a novel olivine sodium phosphate as the anode, resulting in what he says is a safe, cost-effective battery with high energy density; with the added benefits of being comprised of earth abundant materials.
“While the technology is too bulky for portable devices, it has excellent potential for large-scale use, including storing energy from wind turbines and solar farms for later feeding into local electricity grids, as well as use in industry.”
Dr Minakshi said the team is now ready to move beyond the laboratory environment and into larger-scale commercialisation.
