Unearthing the Nano-Silicon Solution

This article is published by EE Power as part of an exclusive digital content partnership with Bodo’s Power Systems.

The interest in silicon anodes is intensifying. The silicon anode battery market is predicted to grow from $1.2 billion in 2021 to $208 billion by 2031, according to Transparency Market Research.

 

In-house battery testing. Image used courtesy of Bodo’s Power Systems [PDF]

Next-Gen Silicon Anode Battery Materials

Silicon anodes, the negatively charged parts of lithium-ion batteries that store lithium ions flowing from the positively charged cathodes during charging, store more lithium ions than graphite, the incumbent technology. This is why silicon’s credentials as an anode is overtaking that of graphite, which is currently the most commonly used anode material, as silicon has a significantly higher energy density. When you consider graphite shortages, global legislative pushes to curb an overreliance on imported battery materials, as well as the demand for more efficient electrification driven by the highest carbon emissions on record, it is clear that silicon offers a promising solution. 

Ionic MT is addressing the unmet need for next-generation silicon anode battery materials with its drop-in nano-silicon anode product, Ionisil, in a unique way. Ionic MT is vertically integrated through control of its Utah-based halloysite clay deposit, the source of the nano-silicon feedstock refined at its nearby battery materials production facility.

The vertically integrated approach has been attributed to the success of the likes of Tesla, allowing full control of processes and the ability to apply, adapt, and innovate technologies domestically. It also exemplifies the domestic approach to green technologies, a movement legislated by the Inflation Reduction Act. Other countries, such as the U.K., are exploring similar legislative equivalents to regulate and strengthen the battery materials supply chain.

Ionic MT’s halloysite deposit, Halloysite Hills, is the largest high-purity deposit in the world. This open pit mine can be easily mined without water, chemicals, or explosives.

The mine differs from the typical image that a ‘mineral mine’ conjures as it blends with the surrounding mountain range and is reseeded with natural flora after exploration. Sustainability is central to Ionic MT’s ethos and starts at the source with its halloysite feedstock. The company has developed what it claims to be the greenest, most scalable process to produce nano-silicon material on the market for higher-capacity lithium-ion batteries. Based on initial reserves, over 600,000 metric tonnes of finished nano-silicon can be made over the life of the mine, equivalent to 6 million metric tonnes of synthetic graphite based on silicon having approximately 10x higher energy density. Significant new halloysite reserves via extensive drilling programs are also being discovered.

 

Nano-silicon material in the Ionic MT lab. Image used courtesy of Bodo’s Power Systems [PDF]

 

The nano-silicon technology utilizes the natural nanotubular structure of halloysite, a naturally occurring aluminosilicate mineral. Halloysite has a nanostructure synthesized in the ground over the last 35 million years, which is applied using a top-down synthesis process that requires significantly less energy input using a continuous process. The unique nano-silicon structure addresses the challenges conventional silicon commonly faces, namely the battery's swelling and degradation, which can occur over repeated charge-discharge cycles, causing capacity loss. Conventional silicon swells three times its size when in contact with lithium during charging, causing capacity loss per charge and rupturing, reducing battery lifespan.

 

Halloysite and nano-silicon electron microscopy images. Image used courtesy of Bodo’s Power Systems [PDF]

 

Nano-Silicon Production Process

However, Ionisil, with its nanotubular porous structure inherited from the halloysite, means the silicon can swell into its pore volume, reducing battery degradation. The nano-sized particles can also improve cycling stability.

The nano-silicon production process creates important critical mineral by-products. Every metric tonne of nano-silicon produced results in two metric tonnes of alumina, listed as a U.S. essential mineral. The acid used during manufacturing can also be reclaimed, producing additional by-products from reductants.

Ionic MT’s unique approach to battery materials yields interesting results. Ionisil Gen-1 has achieved the highest stable capacity nano-silicon on the nano-silicon market, the key to a longer-range battery. As product development continues and Ionic MT breaks new ground with the capacity of its nano-silicon material, the company will move to its new 36,000-square-foot facility in August to commence commercial-scale nano-silicon production. It will work toward 2,000 metric tonnes per year, and its mission to electrify the future.

Learn more about Ionic Mineral Technologies at Ionicmt.com.

 

This article originally appeared in Bodo’s Power Systems [PDF] magazine