Battery chemistry breakthroughs are charging the US EV industry’s drive to cut costs and deliver plug-in cars with longer ranges and more affordable price tags.
First, some battery basics. Lithium-ion batteries contain two electrodes: cathodes (the positive electrodes) and anodes (the negative electrodes). Electricity is generated by the movement of electrons between the two. Many of the breakthroughs up to now have been on the cathode side, but anodes are increasingly becoming the site of new innovations.
Among the emerging developments are lithium-silicon batteries, which replace graphite, the dominant anode material used in EV batteries today, with silicon.
One of the companies at the cutting edge of this tech is Sila Nanotechnologies, an Alameda, California-based battery materials company founded in 2011. Its goal is to supply silicon anodes for millions of EV batteries in the coming years. It took strides toward achieving that when it broke ground in November on a new plant in Moses Lake, Washington, that will produce Sila’s Titan Silicon anode for Mercedes-Benz and other automotive customers starting in 2025.
Sila says its silicon-based anode delivers 20% higher energy density than the best batteries on the market today. Eventually, it aims to deliver a 40% improvement. These advances are aimed at boosting the range of EVs and reducing charging times. They can also drive cost reductions, as higher energy density enables battery makers to use fewer battery cells to achieve the same range.
“This is the biggest battery chemistry breakthrough in probably 30 years,” Gene Berdichevsky, Sila’s CEO and co-founder, told Tech Brew. “The biggest challenge now is scaling up the production of this material.”
Industry stakeholders and experts see the development of silicon-based anode material as one of several key innovations enabling battery chemistry breakthroughs, along with solid-state batteries and sodium-ion batteries. Bloomberg NEF estimates that technologies that rely on silicon, lithium, and hard carbon could displace 46% of graphite demand by 2035.
“The chemistries of today, of iron cathodes and nickel cathodes, those are going to stick around for a long time,” Berdichevsky said. “But silicon will emerge, and it will enable vehicles that appeal to more and more consumers—vehicles with even longer range, faster recharge times, and lower cost.”
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Shifting to silicon-based anodes could also help the industry reduce its reliance on graphite at a time when the US is working to move away from China’s dominant EV supply chain. The vast majority of the world’s graphite is mined, refined, or processed in China, and new export controls the country placed on graphite underscore potential vulnerabilities for the US EV industry.
It’s becoming more common for makers of battery materials to mix silicon with graphite for anode material, Sam Abuelsamid, principal research analyst at Guidehouse Insights, told Tech Brew.
“Increasingly it’s a mix of graphite with a bit of silicon mixed in there, as well, which helps to improve the energy density,” he said.
“Graphite’s expensive, and everybody would like to move away from graphite, both for cost reasons and also for supply-chain resiliency,” he added. “Silicon—you can find sand anywhere. It’s everywhere…You can process the silicon pretty easily; graphite, it’s a little more complicated.”
Another company that’s placing its bets on silicon anodes is OneD Battery Sciences, a Palo Alto-based startup with backing from GM’s venture arm.
OneD’s technology is centered on a graphite-silicon composite that boosts energy density. The company’s technology, Sinanode, fuses silicon nanowires to graphite. CEO and co-founder Vincent Pluvinage told Tech Brew that the innovation could result in as much as a 25% cost reduction for battery packs.
OneD, which is building a pilot plant in Moses Lake, plans to announce the location for a new manufacturing facility in North America early next year. In 2022, OneD completed a Series C funding round that drew investments from GM Ventures and Volta Energy Technologies; its technology could someday be used in GM batteries.
“By having the ability to enhance the graphite that is being processed in North America, we drastically change the strength of the supply chain without disrupting it,” Pluvinage said.