Carbon coating on silicon oxide (SiOx) is widely used to enhance electrical conductivity and interfacial stability. However, the effect of coating thickness on electrochemical performance and electrode microstructure remains insufficiently understood. Here, we synthesize carbon-coated SiOx with controlled coating thickness through chemical vapor deposition. The carbon coating on SiOx improves its interaction with the carbon-binder domain, thereby promoting more homogeneous dispersion within the electrode. However, excessively thick carbon coating hindered Li-ion transport and increased polarization despite improved electronic conduction, whereas thin coating fails to provide sufficient electronic pathways. Consequently, an optimal carbon coating thickness enables balanced ion/electron transport, leading to reduced electrode resistance and improved initial Coulombic efficiency. Furthermore, SiOx/graphite||LiNi0.6Co0.2Mn0.2O2 (NCM622) full cells with optimally coated SiOx exhibit superior rate capability and enhanced cycling stability compared to those with bare SiOx. These results clearly demonstrate that carbon coating thickness is a critical parameter for balancing ionic and electronic transport while simultaneously improving electrode microstructure.