Numerous research labs have been working to bring the potential benefits of silicon-based chemistry to lithium-ion batteries. Those benefits include improved affordability, stability, and energy density. The race is on to see which approach, by which organization, will prove the most effective in production as well as in the confines of a laboratory.
The Coretec Group, is an Ann Arbor, MI-based startup that believes in the potential of silicon anodes to take lithium-ion battery performance to the next level. Battery Technology had the opportunity to talk to Dr. Michelle Tokarz, VP of Partnerships and Innovation at The Coretec Group, about how the company aims to reach that level — and what effect the passage of the Inflation Reduction Act (IRA) may have on them and their competitors.
What can you tell us about Endurion?
Dr Michelle Tokarz: The Endurion project is The Coretec Group’s initiative to improve the performance of lithium-ion batteries. The name Endurion is a play on words, Endur pointing to enduring and ion related to batteries. Coretec’s battery development program is centered on lithium-ion batteries with a silicon-based anode. We are improving silicon-anode technologies such that they can find widespread use in lithium-ion batteries, improving cycling stability and energy density.
How does Endurion technology stand out from other silicon-based anode competitors in the market?
Tokarz: In September 2022, The French Alternative Energies and Atomic Energy Commission (CEA) tested the ability of our Cyclohexasilane (CHS) technology to generate silicon nanowires, and has found promising initial results. For example, they’ve discovered that CHS demonstrated the lowest deposition temperatures they had seen so far, as well as the largest yields of silicon nanoparticles.
While CHS was the genesis of our battery program, being innovators in silicon, we’ve also begun to work with additional silicon precursors to create our unique “bottom-up” silicon-based nanoparticles through wet chemistry in such a way that we can have precise control over the size, size distribution, and nature of the accompanying artificial SEI layer. Others in the industry that use silicon nanoparticles largely use particles that have been created using mechanical ball-milling processes. Such methods produce an order of magnitude larger particles, which can contribute to longer charging times and are less uniform and trickier for the kinds of surface modifications that The Coretec Group is performing.
What are the challenges when building a silicon-based anode solution, e.g., an unstable SEI layer?
Tokarz: The nature of lithium-ion batteries is such that an SEI layer will form within the first few cycles, and this SEI layer is essential to the proper performance of a lithium-ion battery as it serves as a passivating layer. The issue comes when portions of SEI layer material break off the anode active material upon delithiation —lithium leaving the anode during discharge—. This occurs because the SEI layer generally does not shrink with the active anode materials. In fact, it buckles and breaks. The more this happens, the more lithium is consumed and unavailable for charging/discharging. Additionally, “dead lithium” that is bound up in this floating SEI material tends to cause internal resistance in the battery, resulting in poorer performance over time.
How does Endurion’s technology affect the degradation of a battery?
Tokarz: “Degradation of a battery” is an interesting phrase. All lithium-ion batteries degrade over time and use. The key is to mitigate that degradation and create a battery with the proper performance needed for the intended application. Endurion's technology aims to make lithium-ion batteries with silicon anodes that will last longer and charge faster. We are working with the solid-electrolyte-interphase (SEI) using chemical methods, so we have precise control over the size and type of SEI layer.
Additionally, we intend to use nanosized particles that are below the critical size that has been found by researchers to be the lower limit of diameters that will not fail catastrophically through pulverization or disintegration. Both of these efforts should directly improve the cycle life of anodes made with our materials.
How will the Inflation Reduction Act (IRA) impact the future growth and development of Coretec Group?
Tokarz: The Inflation Reduction Act (IRA) has positively impacted the Cortec Group because it has allowed American companies that make clean energy products, like EVs, to get investments that have never been done before. Because of this, there will be more interest in our Endurion project by putting silicon anode active materials for lithium-ion batteries and CHS to use in cleantech and emerging technologies. The timing couldn’t be more perfect, now that our revolutionary silicon anode active material is changing the markets for electric cars and energy storage.
Can you share your thoughts on the immediate and long-term impact the IRA might have on EV battery and energy storage developments in America?
Tokarz: The immediate and long-term impacts of the IRA on domestic EV battery manufacturing in the U.S. are of great significance because it should encourage automakers to transfer production to the United States. The IRA has given billions of dollars to support domestic manufacturing production and other measures that will strengthen the US supply chain, such as increasing credit levels for electric vehicle supply equipment (EVSE) and EV tax credits. In addition, it includes tax breaks and billions in funding because the Act also provides tax breaks for EV battery manufacturing companies.
The Act will pay up to 30%, or about $10 billion, to cover the cost of new or updated manufacturing facilities to make parts for EVs and EVSE, as long as labor standards are met. With these manufacturing incentives and residential EV credits tied to domestic content standards, the focus is on getting essential resources from the US or countries with free trade agreements. This will help strengthen the supply chain and ensure politics and tariffs cause fewer problems. In the short term, these policies will limit what home EV buyers can do, and it will take time to find and build the right ones. But in the long term, they could lower costs and make us less dependent on China. The emphasis on domestic EV and battery manufacturing will also help to achieve the IRA's goal of creating more than 9 million new jobs over the next decade.
How do you foresee the future of the American battery supply chain?
Tokarz: Given how far along the development of different types of battery chemistry is right now, time is of the essence. For the commercialization of new technology to go smoothly, it will be important to bring together the people who need to know about things like chemistry, rheology, scalability, and manufacturing. The industry is moving towards developing affordable, faster-charging, and larger-capacity Si-based batteries. Even when the field has a long way to go, knowing we are in this market at the right time and with the right team, the dream of making next-generation batteries is soon to become a reality.