An Innovative 3D Printing Approach for Processing Si/SiOC Anodes for Li-ion Batteries with Potential Application as High Areal Energy and Power Density Electrodes

A facile method for fabricating a silicon nanoparticle–silicon oxycarbide composite anode material for lithium-ion batteries is developed using the polymer-derived ceramic (PDC) route. A cellular structure has first been printed via fused filament fabrication (FFF) using a Si nanoparticle-loaded thermoplastic polyurethane (TPU) filament, and subsequently infiltrated with a preceramic polymer, crosslinked at 160 °C, and pyrolyzed at 900 °C under nitrogen. For comparison, a pure SiOC ceramic has also been fabricated under identical conditions using commercial TPU filament. X-ray diffraction confirms the dispersion of Si nanoparticles within an amorphous SiOC matrix, while thermogravimetric analysis reveals free carbon contents of 39 wt% (SiOC) and 24 wt% (SiNPs/SiOC). Incorporation of Si nanoparticles into the SiOC matrix leads to improved reversible capacity, cyclic stability, and rate capability. The SiNPs/SiOC composite delivers initial reversible capacities of 990, 800, and 740 mAh g⁻¹ at current densities of C/20, C/10, and C/5, respectively.