Evonik Chemicals introduces silicon-carbon composite anode material to improve lithium-ion batteries

Graphite has always been the preferred material for the negative electrode of lithium-ion batteries, but as demand continues to change, such as electric vehicle batteries requiring higher capacity and faster charging speeds, people have been looking for materials that can replace graphite, among which silicon-carbon composites are considered to have great potential. Compared with graphite, silicon-carbon composites have higher theoretical storage space capacity, larger volume capacity, very low discharge voltage and lower cost.

According to foreign media reports, German chemical company Evonik has launched Siridion® Black, a silicon-carbon composite material that can be used as a new negative electrode material for lithium-ion batteries. The material makes batteries more powerful by increasing energy density and improving fast charging capabilities and energy efficiency.

Peter Friesenhahn, head of Evonik's Silanes business unit, said: "The launch of Siridion® Black is an important milestone in the strategic development of our product portfolio. In the future, we will strengthen our products in attractive, technology-oriented growth markets and strive to become an innovative partner for our customers." The new high-performance material also completes Evonik's battery material portfolio. Previously, the company also provided negative electrode active materials and fumed metal oxides for separator coatings.

“Graphite has long been used as anode material for lithium-ion batteries. But if we want to increase battery capacity, we need new materials that enable fast charging,” said Dr. Björn Borup, Head of Marketing for Battery Materials at Evonik’s Silanes business unit. “As an additive, Evonik’s silicon-carbon composites can be quickly integrated into existing anode materials and production processes and can be well combined with other battery materials.”

The powder is produced by gas phase synthesis and consists of many isolated, unsintered spherical nanoparticles. Within the amorphous particles, the carbon concentration increases from the inside out, resulting in a high degree of stability. "Due to the higher carbon content on the surface, the particles are better protected from oxidation and are easier to process," said Dr. Julia Lyubina, head of development and commercialization of Siridion® Black.

The high-performance anode material was developed by Evonik's Research & Innovation and Silanes business units. Together with the University of Duisburg-Essen, the research is aimed at making lithium-ion batteries even more powerful. The German Federal Ministry of Economic Affairs and Energy is funding the project until 2023.

“Siridion® Black offers customized solutions, giving battery anode manufacturers and their customers the necessary flexibility to tailor the battery to their requirements,” said Lyubina. Moreover, manufacturers of wearable or mobile devices may also appreciate this design freedom.