New Aluminum Yolk-shell Nanoparticle Improve Li-ion Batteries

Posted: Aug 12 2015, 5:29am CDT | by , in News | Technology News


New Aluminum yolk-shell Nanoparticle Improve Li-ion Batteries
The gray sphere at center represents an aluminum nanoparticle, forming the "yolk." The outer light-blue layer represents a solid shell of titanium dioxide, and the space in between the yolk and shell allows the yolk to expand and contract without damaging the shell. In the background is an actual scanning electron microscope image of a collection of these yolk-shell nanoparticles. Image: Christine Daniloff/MIT

MIT and Tsinghua University in China scientists develop new battery design using aluminum.

A new battery design using aluminum could reduce charging times to minutes.

Researchers at MIT and Tsinghua University in China created an electrode made of nanoparticles with a solid shell, and a “yolk” inside that can change size again and again without affecting the shell.

The innovation could drastically improve cycle life, the team says, and provide a dramatic boost in the battery’s capacity and power.

The use of nanoparticles with an aluminum yolk and a titanium dioxide shell has proven to be “the high-rate champion among high-capacity anodes,” the team reports.

Most present lithium-ion batteries use anodes made of graphite, a form of carbon. 

Graphite has a charge storage capacity of 0.35 ampere-hours per gram (Ah/g). Researchers have explored other options that would provide greater energy storage for a given weight for a long time. 

Aluminum is a low-cost option with theoretical capacity of 2 Ah/g. But aluminum and other high-capacity materials, Li says, “expand a lot when they get to high capacity, when they absorb lithium. And then they shrink, when releasing lithium.”

Previous attempts to develop an aluminum electrode for lithium-ion batteries had failed.

That’s where the idea of using confined aluminum in the form of a yolk-shell nanoparticle came in. In the nanotechnology business, there is a big difference between what are called “core-shell” and “yolk-shell” nanoparticles. 

The former have a shell that is bonded directly to the core, but yolk-shell particles feature a void between the two — equivalent to where the white of an egg would be. As a result, the “yolk” material can expand and contract freely, with little effect on the dimensions and stability of the “shell.”

“We made a titanium oxide shell,” Li says, “that separates the aluminum from the liquid electrolyte” between the battery’s two electrodes. The shell does not expand or shrink much, he says, so the SEI coating on the shell is very stable and does not fall off, and the aluminum inside is protected from direct contact with the electrolyte.

​The research team included Sa Li, Yu Cheng Zhao, and Chang An Wang of Tsinghua University in Beijing and Junjie Niu, Kangpyo So, and Chao Wang of MIT.

The paper titled "High-rate aluminum yolk-shell nanoparticle anode for Li-ion battery with long cycle life and ultrahigh capacity" has been published in journal Nature Communications.

See also the new research on batteries made from paper.

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The Author

<a href="/latest_stories/all/all/2" rel="author">Luigi Lugmayr</a>
Luigi Lugmayr () is the founding chief Editor of I4U News and brings over 15 years experience in the technology field to the ever evolving and exciting world of gadgets. He started I4U News back in 2000 and evolved it into vibrant technology magazine.
Luigi can be contacted directly at




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