Structural design and solid electrolyte interphase modulation of SiOC-based anodes via N-doping for fast-charging lithium-ion batteries

Silicon oxycarbide (SiOC)-based anodes are promising for enhancing the energy density of lithium-ion batteries (LIBs), but face challenges like slow kinetics and poorly stable solid electrolyte interphase (SEI). Here, we address these limitations through nitrogen doping to regulate the composition of free carbon and SEI in SiOC-based anode, thereby enhancing the reaction kinetics and stability. With combined experimental and theoretical studies, N-doped SiOC-based particles with engineered carbon defects effectively reduce diffusion barriers. Furthermore, N-doped SiOC-based material forms a Li 3 N/LiF-dominated SEI with high ionic conductivity and interface stability, leading to exceptional performance. Consequently, N-doped SiOC-based anode exhibits a reversible capacity of 686.2 mAh g −1 with nearly 100 % retention over 1100 cycles at 1.0 A g −1 and stability for 2000 cycles at 2.0 A g −1 . This work highlights the synergistic benefits of structural tuning and SEI modulation, paving the way for fast-charging LIBs and advanced energy storage systems. • Novel N-doping simultaneously introduces carbon defects and N atoms in SiOC. • Carbon defects and N atoms synergistically lower the Li + migration energy barrier. • The formation of an inorganic Li 3 N/LiF-rich SEI is facilitated by N-doping. • N-doped SiOC exhibits high coulombic efficiency and excellent rate capability.