Eggshells could crack renewables puzzle


Murdoch University researchers have found that the humble eggshell, baked and then crushed into a fine powder, could be a cheap alternative to renewable energy storage options.

Dr Manickam Minakshi and his team have been working with researchers around the world to test whether the powder can work as positive and negative electrodes to power lithium-ion batteries used in households to store renewable energy.

Because eggshells are abundant and affordable, it could put green energy potential in the hands of the developing world and be utilised on a larger scale.

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“If we can establish that eggshells can be used as electrodes in powering batteries, the applications of such technology can be enormous,” Dr Minakshi said.

“Using chicken eggshells in this manner not only has the potential to reduce the amount of bio-waste that is produced, but it also has the potential to add considerable value to the renewable energy market.”

Eggshells contain a high level of calcium carbonate and the membrane that sits around the yolk provides a protective protein barrier, which allows researchers to cook the shells at high temperatures and then crush them using a mortar and pestle.

The baking process changes the chemical composition of the eggshell material, allowing it to become a more efficient electrode and conductor of power.

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In experiments using supermarket-bought caged eggs, researchers were able to successfully use eggshells as an electrode – both as a positive anode and a negative cathode.

Dr Minakshi has been working on developing affordable energy storage solutions for several years. In 2012, he and his research team developed a water-based sodium-ion battery, chosen because its chemical properties were similar to lithium, the element that powers most portable electronic devices.

The research is the first of its kind in the world.