Dual-functional SiOC: Achieving record 86% initial Coulombic efficiency in Li-ion batteries and dendrite-free Li metal anodes via (110)-textured deposition

Silicon oxycarbide (SiOC) holds promise as a high-capacity anode material for lithium-ion batteries, but its performance has been consistently limited by a low initial Coulombic efficiency (ICE). In this work, a carbon-coated SiOC composite (C/SiOC) was synthesized via CVD, exhibiting a significantly increased proportion of reversible Si–O–C units (94.7%) and a reduced surface area (3.629 m² g⁻¹). As a result, the C/SiOC anode delivered stable cycling over 800 cycles and achieved a remarkably high ICE of 86%. Notably, the C/SiOC composite also served as an effective host for lithium metal deposition, reducing the nucleation overpotential to 1.7 mV and promoting (110)-textured Li growth, thereby suppressing dendritic formation. This synergistic functionality resulted in excellent long-term stability in half cells (780 cycles at 1.0 mA cm⁻²), symmetric cells (10,000 hours at 1.0 mA cm⁻²), and full cells (800 cycles at 1.0 C), highlighting the strong potential of C/SiOC for advanced lithium-based battery systems, including anode-free architectures.