Multi layer silicon anode to boost Li-ion battery performance

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Researchers at the Okinawa Institute of Science and Technology are the latest to publish work exploring the use of silicon anodes in lithium-ion batteries.

In its work, the team has designed an anode featuring nanostructured layers of silicon. Said to resemble a multi-layered cake, the construction is claimed to retain the advantages of a silicon anode while preventing its physical collapse.

The problem is that while an atom of silicon can bind four atoms of lithium, accommodating those atoms means the volume of a silicon anode swells significantly, leading to fracturing and loss of structural integrity.

In its approach, the team deposited alternate layers of unstructured silicon films and tantalum metal nanoparticle scaffolds. The result sees silicon sandwiched in a tantalum frame.

“We used cluster beam deposition,” said researcher Dr Marta Haro Remon. “The required materials are deposited on the surface with great control. This is a purely physical method; there is no need for chemicals, catalysts or other binders.”

The work, led by Professor Mukhles Sowwan, is an anode with higher power, restrained swelling and excellent cyclability. The silicon anode has a porosity that allows lithium ions to travel at higher speeds, while silicon channels in the tantalum scaffold allows lithium ions to diffuse through the structure.

The silicon anode is also helping to improve the ability to charge the battery and deliver energy. “The goal in battery technology right now is to increase charging speed and power output,” said Dr Haro Remon. “While it is fine to charge your phone or your laptop over a long period of time, you would not wait by your electric car for three hours at the charging station.”