A facile and low cost method has been investigated in this study to prepare silicon nanoparticles with a conductive carbon shell and engineered voids as anode materials for lithium ion batteries. Several carbon-coating methods have been tried to form a hard and dense carbon shell, while partial etching of Si has been investigated with various etching chemicals and conditions to create engineered voids inside the carbon coated Si nanoparticles. It is demonstrated that the electrochemical performance and cycle stability of Si@void@C depends strongly on synthesis conditions, especially the engineered voids in their structure and composition control in the final product. The higher the Si-to-carbon ratio, the higher discharge capacity it could achieve. Further, as the volume of the engineered void increases, the cycle stability improves. The best properties obtained from these tailored Si@void@C nanostructures are about 3100 mAh/g of specific discharge capacity at the first cycle, and 2500 mAh/g after 300 cycles at the current density of 0.5 A/g. The cycling experiment is still on-going and thus one can expect longer cycle life from these tailored Si@void@C nanostructures.