How scientific, technological developments could bring silicon-dominant anodes into vogue

Developments in the science and technology underpinning silicon-base anode materials have allowed them to reach mainstream commercial viability, according to Gleb Yushin, chief technology officer and co-founder of US-based Sila Nanotechnologies

Sila Nanotechnologies is a battery material developer whose breakthrough technology, named “Titan Silicon,” is a nano-composite silicon (NCS) anode.

The company’s materials drive battery performance enhancements in consumer electronics devices and are intended to power electric vehicles (EVs), starting with the Mercedes-Benz G-Class series.

In an interview with Fastmarkets, Yushin delved into the developments that brought the company’s NCS into viability for silicon-dominant anodes and what the material offers EV and battery makers.

Yushin believes that the technology could help relieve supply tightness and the geographical disparity in the production of another key battery raw material (BRM) – graphite.

Unlike the bulk of the world’s graphite, Sila’s NCS is made in the US, meaning it is aligned with the renewed Western impetus to secure the supply chains of more raw materials – especially those critical for the energy transition.

While silicon and its compounds have previously been used in limited quantities in anodes, it is more recent developments that have allowed the material to be used in higher concentrations in anodes – overcoming challenges related to battery degradation especially.

What NCS offers

By offering a higher capacity compared with traditionally used graphite, NCS-based electrodes are thinner, reducing lithium-ion diffusion distance and helping to yield cost benefits, Yushin explained.

The technology also offers higher energy density (Titan Silicon boosts energy density by up to 40%) and faster charging compared with today’s graphite-based lithium-ion batteries (LIBs), he said.

Yushin calculated that, at their limit, the cost of graphite-anode LIBs will remain around $100/kWh at the pack level.

Sila’s next-generation NCS anodes and cathodes, Yushin said, “will help reduce LIB pack costs down to $50/kWh, making it a suitable technology to power the booming EV market.”

Fastmarkets’ cell cost modeling team estimates that the anode typically makes up 10-15% of the total cost of a typical nickelcobaltmanganese (NCM) cell, with the cathode contributing 50-60%.

“While improvements to the anode are important for fast-charging, lifetime and general performance, it is advancements on the cathode side (as well as bringing down cathode raw material prices) that will really drive down overall cell cost. Improving manufacturing processes and minimizing waste in gigafactories will also play a large role,” Muthu Krishna, Fastmarkets cell cost modeler, said.

“The cell energy density depends on both the anode and the cathode, mostly their capacities and their electrochemical potentials,” Yushin said.

“The ultra-high capacity NCS, in combination with next-generation cathodes, will enable a two times increase in energy density… This means 50% fewer cells would be needed for the LIB pack to offer roughly the same energy,” he said.

The size and the price of an LIB pack would similarly be around 50% smaller, according to Yushin.

“Note that the same next-generation cathodes cannot offer major performance improvements when coupled with graphite anodes,” he said.

A new technology

These developments have led to a major shift in how silicon-based anodes are perceived.

“A decade ago, due to the scientific and technological difficulties overcoming numerous technical challenges, most people in the industry didn’t believe silicon anodes could become reality soon,” Yushin said.

“The main question we hear now is how fast we can scale up Titan Silicon production to meet the TWh-level demands,” he added.

Over the past years, some leading battery companies began introducing small amounts of Japan- or China-produced silicon oxide material into graphite anodes to slightly improve LIB energy density or rate while avoiding excessive degradation.

However, the idea of silicon-dominant anodes was out of the question, Yushin said.

“Now, Titan Silicon can be used in excess of [50% by weight], or replace graphite in the anodes entirely,” he said.

The life cycle of Sila NCS anode automotive cells is similar to that of graphite-based automotive cells or automotive cells comprising graphite, or doped with small amounts of silicon oxide, he said.

Sila is not the only company to see promise in silicon-based materials for anodes.

In 2020, EV maker Tesla announced it would use increased quantities of silicon in its battery anodes versus the prevalent graphite.

Notably, the company said at the time it would be using silicon metal rather than the costlier engineered silicon materials to make its anodes.

At the time, participants in both the silicon metal and graphite markets minimized the impact this might have on the respective markets.

The relatively dispersed global production of silicon helps make it an appealing alternative to other anode materials. Between the US and Canada, North American silicon metal output is around 200,000 tonnes per year, Fastmarkets estimates.

Supply challenges

Despite overall positivity, Yushin did identify a particularly daunting looming challenge for the uptake of silicon, and BRMs generally – supply.

“The new challenges are all about supply – specifically supply from geographically diverse regions,” he said.

A majority of the world’s silicon is produced in China, although this majority is much less significant than it is for the production of other critical BRMs, including graphite and cobalt, which China also refines a global majority of.

Western companies are moving to fill this production gap. In an interview with Fastmarkets earlier this year, Sinova Global shared that it will produce silicon in North America to help fulfill additional demand for silicon, including for battery anodes.

Yushin pointed to legislative action, including the Inflation Reduction Act (IRA), that demonstrates the US and the West is “waking up” to the fact that a “massive percentage” of the precursors of all the input materials to batteries make their way into the West from China.

“When you think about battery technology as the path to replacing fossil fuels and oil and gas, we don’t want to be setting ourselves up to be dependent on foreign nations for our critical supply for our energy resources,” he said.

While welcoming the economic incentives introduced by the IRA to produce precursor, raw materials and eventually electrode materials for LIBs domestically and in free trade countries, Yushin pointed to continued obstacles in securing capital and the regulatory process to establish new factories and mines.

“Despite having many natural resources in the US, there are still regulatory hurdles around things like building up new mines, for example,” he said.

“From the economic standpoint, we may also need to consider access to large capital and low interest rates to stimulate strategically important investments in both raw materials and battery material processing, as China already offers these to Chinese battery-related industries,” he added.

“We still have to get to a place where it’s easier to secure capital and build those factories and mines because otherwise, the supply chain really isn’t going to change,” he said.

Previous Fastmarkets reporting found that there remains confusion around the eligibility of materials to qualify for the financial incentives the IRA offers, specifically concerning the material’s origins.

A lack of clarity has slowed IRA-linked investments, according to Abigail Wulf, vice president and director of the Securing America’s Future Energy (SAFE) Center for Critical Minerals Strategy.

Keep up to date with the latest news and insights on our dedicated battery materials market page.

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