The Influence of Microporous Carbon Matrices on the Performance of Silicon-Carbon Nanocomposite Anode Materials

Chemical vapor deposition (CVD) of nanoscale silicon in porous carbon matrices is an effective way to address the volume expansion of silicon anodes. This work studies two commercial resin-based microporous carbons, PC-1 (irregular) and PC-2 (quasi-spheroidal), as silicon hosts to fabricate nanocomposite anode materials (SC-1 and SC-2) by CVD, to clarify how carbon matrices affect the electrochemical performance of the anode materials. Experimental results reveal that PC-2 possesses a higher micropore volume, which may enable more abundant and confined loading sites for nano-silicon. Coupled with its spheroidal morphology, smaller particle size, and superior graphitic ordering. These attributes collectively establish a continuous, low-resistance electron conduction network and intrinsically enhance charge carrier mobility, thereby reducing electrode polarization and improving reaction kinetics. Consequently, SC-2 delivers good cycling stability and rate capability. Furthermore, atomic force microscopy (AFM) indicates that PC-2 possesses a higher Young’s modulus than PC-1, endowing it with stronger mechanical confinement. This constrains the volume changes of silicon during lithiation and de-lithiation, thereby minimizing irreversible electrode expansion, as evidenced by the lower irreversible swelling of SC-2. By systematically correlating material properties with electrochemical outcomes, this study clarifies the pivotal roles of carbon matrices in silicon-carbon nanocomposite anode systems.