Silicon nanowires promise much better lithium-ion EV batteries

As automakers and battery cell manufacturers race to develop more efficient and cost-effective EV batteries, there is one material that has gained significant traction in replacing graphite in the anode: silicon.

To that end, California-based startup OneD Battery Sciences has produced silicon nanowires that can be melted directly onto the commercial graphite particles found in the anodes of batteries.

The consequences? Potentially tripling the energy density of the anode, reducing charging times and lowering the overall cost of the battery.

Why silicon can be a game changer

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According to research from the PNNL lab, silicon has a theoretical energy capacity ten times that of graphite and can absorb lithium ions much faster during charging, shortening the duration of the process.

For that reason, several companies and automakers are investigating the use of silicon in the anode, while Tesla and Porsche are already mixing small amounts of the material with battery-powered graphite in the Model Y and Taycan, respectively.

But adding silicon to the anode poses certain challenges.

The tendency of the material to expand about 400% of its original size during the charging cycle can cause the silicon particles to crack and damage the layer of the solid electrolyte interface, which hinders the lithium ion conductivity and electric current.

This leads to energy loss and battery degradation.

According to Vincent Pluvinage, CEO of the startup, existing methods of solving this problem (such as silicon nanoparticles) have proven limited due to high production costs and lack of compatibility with the wider EV supply chain.

The OneD Battery Sciences solution?

The company has developed a special platform called Sinanode, which attaches the silicon nanowires to the anode using silane, nitrogen and electricity.

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