Porous carbon nanofibers were fabricated by electrospinning in a precursor solution containing polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and N,Ndimethylformamide. During thermal treatment, PMMA decomposition caused nanofibers to transform from a solid to a porous structure. Removal of PMMA also decreased the fiber diameter and increased the pore volume of the carbon nanofibers, resulting in a substantial increase in specific surface area. We used these web-type fiber films directly without a binder as an anode for lithium ion batteries. The electrochemical performance of these 5:5 PAN/PMMA-derived carbon nanofibers exhibited a discharge capacity of 446 mAh/g under a current density of 150 mA/g, which was approximately two times that of the neat PAN-derived carbon nanofibers. Additionally, the discharge capacity retention of the 5:5 PAN/ PMMA-derived carbon nanofibers was nearly the same as that of the neat PAN-derived carbon nanofibers, indicating favorable cycle stability.