We report a simple process to coat silicon monoxide (SiO) particles with nitrogen-doped carbon layers (NC-SiO) by using a nitrogen-containing ionic liquid. The nitrogen-doping addresses the moderate electric conductivity of SiO particles as large as 20 μm and thus enables NC-SiO to exhibit substantially improved specific capacity and rate performance as compared to those of bare carbon-coated SiO (C-SiO) and bare SiO counterparts. Due to the simplicity of the coating procedure, the current approach should be readily applicable to other lithium battery electrodes that suffer from low electronic conductivities.