Although graphite has been used as an anode material for power batteries for decades, its large volume, high weight, and physical and chemical limitations make it difficult to meet the high energy density requirements of electric vehicles. Therefore, silicon based anode materials are gradually replacing graphite and becoming a new direction for power battery research and development due to their ultra-high theoretical specific capacity.
Silicon Valley startup Sila Nanotechnologies recently announced that it has developed the first batch of process flows for large-scale production of silicon based anodes. The CEO of the company stated that this new material is named “Titan Silicon” and is currently undergoing certification for automotive manufacturers. It will be put into production at the new factory by the end of next year. According to the plan, the company’s annual production capacity will reach 200000 units by 2026 and 1 million units by 2028, to be used for premium sales of high-end electric vehicles.
It is reported that the electric SUV EQG launched by Mercedes Benz in 2025 will use the silicon based anode battery provided by CATL, whose energy density will be 20-40% higher than that of products of the same level, and the “Titan Silicon” of Sila Nanotechnologies will be used as the anode material. EQG is one of Mercedes Benz’s highest priced electric vehicles, and its prototype is undergoing testing in the Arctic. Public information shows that the energy density of EQG batteries will reach 800Wh/kg, nearly twice that of batteries of the same size.
With the development of lightweight electric vehicles, silicon based anode batteries have become a new technology that major car companies and battery manufacturers are competing to develop. Since the 1980s, graphite has been the mainstream anode material. But graphite has a large volume, weight, and energy storage limit. The current silicon content of high-end batteries is about 5%, but the theoretical specific capacity of silicon based anodes is 10 times that of graphite, which is an important way to achieve high energy density goals.
Silicon based anodes also face challenges, as the volume of silicon expands three times after charging, significantly reducing performance even at low concentrations. The mainstream solution is to wrap silicon particles in a certain structure to prevent expansion. Sila Nanotechnologies uses a porous shell to bind silicon particles, with an expansion rate of only 6%.
CATL is a leader in the field of silicon based anode, and developed 304Wh/kg sample battery in 2019. The Kirin battery adopts a silicon based anode, with a range of over 1000km for the pole Kr 009. It will be mass-produced and delivered this year. Tesla also hopes to develop silicon based anodes and acquire SiILion, but progress is unknown.
Porsche has reached a $6.5 billion agreement with Group14 Technologies. GM collaborates with OneD Battery Sciences, and it is unknown who will make the breakthrough first. With the decrease in technology and cost, silicon based anodes are expected to be further popularized.
It is expected that the global demand for silicon based anodes will be 200000 tons by 2025. 50% penetration rate of consumer batteries, 70000 tons; 35% and 20% respectively for cylindrical and square batteries, with a capacity of 130000 tons. Once the silicon based anode reaches full production, the cost will be significantly lower than that of graphite and will soon become the standard. The executive believes that after being on par with graphite, the adoption is only limited by production speed.
He predicts that one-third of electric vehicles will use silicon based anodes by 2030. Silicon based anodes will become mainstream in 2035.