Protective Shells Could Be the Answer for Silicon Lithium-ion Batteries

Phys.org reported that Researchers at the U.S. Department of Energy’s Argonne National Laboratory are looking into a coating that could help make lithium-ion batteries with silicon rather than graphite. Silicon can store approximately ten times more lithium than graphite, according to the publication.
As quoted in the market news:

There’s just one problem: current batteries based on silicon materials don’t last long.
The problem lies in the battery’s chemistry. The electrolyte inside the battery transports lithium ions back and forth between positive and negative electrodes as the battery charges and discharges. The positive electrode contains a lithium-bearing compound, while the negative electrode contains materials such as graphite or silicon.
Lithium ions react with the negative electrode to form a new compound, causing the electrode to expand, while the electrolyte produces a protective coating called the solid electrolyte interphase.
“The ideal solid electrolyte interphase should halt the reaction between the electrode and electrolyte, while allowing the lithium to come through,” said Ilya Shkrob, a chemist in the Chemical Sciences and Engineering Division.
But the coating also needs to expand and contract with the electrode, or else it will crack and the battery won’t work.
Shkrob compared this phenomenon to an imaginary experiment – pumping air into an egg.  The egg starts to expand and the shell cracks. The shell cracks again when the air is released and the egg returns to its original size.

Click here for the full Phys.org article.