###### Abstract  
Polymer-derived silicon oxycarbide (SiOC) ceramics have garnered significant attention as novel silicon-based anode materials. However, the low conductivity of SiOC ceramics is a limiting factor, reducing both their rate capability and cycling stability. Therefore, controlling the free carbon content and its degree of graphitization within SiOC is crucial for determining battery performance. In this study, we regulated the free carbon content using divinylbenzene (DVB) and controlled the graphitization of free carbon with the transition metal iron (Fe). Through a simple pyrolysis process, we synthesized SiOC ceramic materials (CF) and investigated the impact of Fe-induced changes in the carbon phase and the amorphous SiOC phase on the comprehensive electrochemical performance. The results demonstrated that increasing the DVB content in the SiOC precursor enhanced the free carbon content, while the addition of Fe promoted the graphitization of free carbon and induced the formation of carbon nanotubes (CNTs). The electrochemical performance results showed that the CF electrode material exhibited a high reversible capacity of approximately 1154.05 mAh g\({}^{-1}\) at a low current density of 100 mA g\({}^{-1}\) and maintained good rate capability and cycling stability after 1000 cycles at a high current density of 2000 mA g\({}^{-1}\). SiOC anode; polymer-derived ceramics; free carbon; carbon nanotubes +
Footnote †: journal: _M_odel  
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However, two key issues need to be addressed when using SiOC as an anode material: the densification and non-porous characteristics of SiOC ceramics and the inherently low electrical conductivity of SiOC ceramics, which leads to reduced initial Coulombic efficiency (ICE), cycling stability, and rate performance [15]. Common porosity-inducing methods include the sacrificial template method, where low-boiling-point polysiloxanes (PDMS) are blended with silicone oil, leaving a porous structure after the template's removal during sintering [16]. To improve material conductivity, physical blending with carbon materials is typically employed. In general, adding highly conductive materials such as graphite [17], graphene [18], and CNTs [19] to the SiOC system is a common and effective approach to enhance electron mobility and cycling stability. However, graphene and CNTs are relatively expensive and prone to agglomeration within the system. Therefore, some researchers chose phenyl-rich silicone oils as raw materials to increase the carbon content of ceramic materials after pyrolysis. However, due to the limited phenyl groups contained in silicone oil itself, it was not possible to control the free carbon content generated during the pyrolysis of the precursor. Consequently, researchers attempted to introduce more carbon sources and increase the free carbon content by crosslinking poly(methylhydrosiloxane) (PMHS) with divinylbenzene, thereby enhancing the carbon thermal reduction reaction at high temperatures and promoting the formation of SiC, and applied this material in the field of radar absorption. Research on carbon-rich SiOC ceramics generated at low temperatures as anode materials for lithium batteries has not been extensively reported [20; 21; 22]. More importantly, the free carbon phase formed in this way is a randomly distributed amorphous structure that is primarily isolated by the tetrahedral structure of the SiO\({}_{x}\)C\({}_{y}\) glass phase. This impedes the establishment by free carbon in the ceramics of a coherent or interconnected conductive network, leading to obstructed electron transport pathways during charge-discharge processes and reduced rate performance [23; 24; 25]. Generally, graphitized carbon, compared to amorphous carbon, offer better structural stability and conductivity [26]. Therefore, controlling the free carbon content and its degree of graphitization within a SiOC ceramic matrix is a critical challenge.