‘Yolks’ and ‘shells’ could be ‘eggciting’ news for rechargeable batteries

10 Aug 2015

A team of researchers believes it may have cracked the issue of rechargeable battery degradation with a new model, which resembles an egg with a shell and yolk structure, that drastically improves battery life.

For years now, the electrode within rechargeable batteries has been a source of frustration for researchers as, over time, the drastic expansion and retraction it experiences during each charging cycle sees it deteriorate over time.

With each cycling of the electrode’s skin layer, the lithium battery loses its performance gradually as part of an irreversible process.

Now, however, researchers from MIT in the US and Tsinghua University in China have developed a novel new method that has created an egg-like electrode.

According to MIT News, the electrode is made of nanoparticles that form a solid shell-like structure that contains the ‘yolk’, which is capable of expanding and retracting without affecting the shell.

Publishing its findings online, the team’s electrode differs from standard electrodes in that it uses aluminium for the yoke and titanium dioxide as the shell, rather than graphite.

Rechargeable batteries egg

An illustration of the egg-like electrode. Image via Christine Daniloff/MIT

While graphite has a charge storage capacity of 0.35 ampere-hours per gram (Ah/g), aluminium is capable of achieving 2Ah/g.

Prof Ju Li and the team said that all the materials used in the experiment are relatively inexpensive and, with the right methods, could be scalable for manufacturing rather than just a lab experiment.

It is envisioned that it could be used for devices that require a high power and an energy dense battery.

Speaking as someone outside of the project, David Lou, an associate professor of chemical and biomolecular engineering at Nanyang Technological University in Singapore, said: “These yolk-shell particles show very impressive performance in lab-scale testing.

“To me, the most attractive point of this work is that the process appears simple and scalable.”

Lightbulb in egg image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic