Fe/FeO Nanoparticles‐Decorated Porous SiOC Hierarchical Spheres Enable Robust LiF‐Rich Solid Electrolyte Interphase and Ultrastable Lithium‐Ion Storage

Abstract Amorphous silicon oxycarbide (SiOC) demonstrates high capacity for anode material of lithium‐ion batteries (LIBs). However, its low initial coulombic efficiency (ICE), poor electrical conductivity, and unstable solid electrolyte interphase (SEI) present significant challenges for practical application. Here, porous SiOC hierarchical spheres are elaborated by pyrolysis of cooperatively self‐assembled mesostructure, followed by an alkaline chemical etching process. Moreover, their electronic conductivity and mechanical strength are enhanced by decorating with well‐dispersed Fe/FeO nanoparticles (NPs). The cooperative interaction between the 3D nanoporous SiOC framework and its interconnected hierarchical structure provides rapid diffusion pathways and facilely accessible active sites for Li + ion insertion. The enhanced electronic and ionic conductivity of SiOC‐Fe anode facilitates the formation of a robust LiF‐rich SEI layer, which is found to be ionically more conductive and enables effective passivation of the anode/electrolyte interface, thereby ensuring long‐term cycling stability. Owing to the special nanostructure engineering and SEI, our prepared SiOC‐Fe anode exhibits an excellent cycling stability (635.3 mAh g −1 after 1200 cycles at 1.0 A g −1 ) as well as outstanding rate performance (277.3 mAh g −1 at 2.0 A g −1 ). Furthermore, the full cells assembled with an LiFePO 4 cathode demonstrate a high specific capacity of 140.0 mAh g −1 after 100 cycles. The work provides valuable insights into designing SiOC‐based anodes through metal NPs modification and nano‐morphologies construction for advanced LIBs.