Monolithic Composite Electrodes Comprising Silicon Nanoparticles Embedded in Lignin-derived Carbon Fibers for Lithium-Ion Batteries

We report direct manufacturing of high-capacity carbon/silicon composite fiber electrodes for lithium-ion batteries produced via a flexible low-cost melt processing route, yielding low-cost stable silicon particles coated in situ by a 10 nanometer thick protective silica layer. The core-shell silicon/SiO2 islands are embedded in electrochemically active and electronically conductive carbon fiber derived from lignin precursor material. The silicon-silica-carbon composites exhibit capacities exceeding 700 mAhg(-1) with Coulombic efficiencies in excess of 99.5%. The high efficiency, stability, and rate capability are linked to the nanocrystalline structure and abundant, uniform nanometer-thick SiO2 interfaces that are produced during the spinning and subsequent pyrolysis of the precursor blend.