Berzelius (Nanjing) Co Ltd, a leading developer and manufacturer of silicon anodes, announces its breakthrough high-capacity pure silicon anodes with zero graphite. These innovative anodes enable battery cells to achieve an impressive energy density of 400 Wh/kg while maintaining exceptional power capabilities. This was made possible through the integration of OCSiAl’s single-wall carbon nanotubes, resulting in cells with outstanding performance, high rate capabilities, and extended cycle life.

Single-wall carbon nanotubes, nature’s longest and most flexible material for conductivity and reinforcement of electrodes, have gained widespread recognition as a key solution that significantly mitigates silicon anode degradation. A recent study conducted by a research group at Dalhousie University, Canada, led by renowned electrochemist Dr. Jeff Dahn, one of the world’s most highly cited researchers and a key Tesla research partner in batteries, highlighted their impact: “High-capacity high volume expansion materials such as silicon and SiO must be used in conjunction with more stable electrode materials like graphite to reduce the mechanical degradation caused by volume change. Single-walled carbon nanotubes are shown to be a simple yet effective drop in addition to improving electrical connectivity and increasing capacity retention in these silicon-based composite negative electrodes.”

Unlike carbon black or multi-wall carbon nanotubes, single-wall carbon nanotubes form robust long-range connections that withstand silicon anode expansion and prevent degradation. Since 2014, OCSiAl has been the only company producing single-wall carbon nanotubes at an industrial scale.

“For eight years, we have been developing customized formulations with OCSiAl single-wall carbon nanotubes, which help hold electrode particles together and prevent battery degradation,” says Dr. Cen Wang from Berzelius. “Single-wall carbon nanotubes are effective even at ultralow concentrations. To improve the cycle life of systems with 10% silicon content, we use only 0.05–0.06% nanotubes. For systems with 30% silicon, we incorporate 0.15% nanotubes. The higher the silicon content in the anode, the more critical single-wall carbon nanotubes become. In our pure silicon system, nanotubes are essential for creating a robust network to prevent rapid degradation.

The primary consumers of these high-silicon content material systems, enhanced by OCSiAl’s single-wall carbon nanotubes, include manufacturers of electric vehicles, drones, power tools, and aerospace components. As the market of end products continues to expand, Berzelius is committed to further improving battery performance by pushing the limits of cycle life, swelling, and rate capabilities with single-wall carbon nanotubes. The company introduced its commercial silicon anode materials in 2020 and began constructing a 20,000-ton manufacturing facility in 2022. The first phase of this factory, with a 400-ton annual production capacity, was completed in November of 2022 and has since been supplying silicon material globally. This facility is one of the largest in the battery industry dedicated to pure silicon anode materials.