Lithium-ion batteries achieve 250% higher density with silicon anodes

Scientists at the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in Germany have developed a new class of fiber-based silicon anodes for lithium-ion batteries that could increase energy density by up to 250%. Unlike conventional graphite anodes, which store about 370 mAh per gram, silicon theoretically offers over 4,200 mAh per gram, promising significantly higher capacity at comparable cost. However, silicon’s tendency to expand up to 300% during lithium absorption has caused cracking and rapid battery failure in past attempts. The new approach uses flexible, electrically conductive nonwoven fiber substrates to accommodate silicon’s volume changes, preventing damage during charging cycles. The FACILE project, involving regional partners, aims to produce silicon anodes with a practical capacity of at least 1,000 mAh per gram, translating to a substantial boost in battery energy density. The team has begun integrating these anodes into small test cells and plans to refine and scale production for larger cells suitable for electric vehicles (