In this study, F-substituted 0.5Li(2)MnO(3) center dot 0.5LiNi(1/3)Co(1/3)Mn(1/3)O(2) high porous nanofibers were successfully prepared by electrospinning. X-ray diffraction patterns showed that the synthesized materials had layered sigma-NaFeO2-type structure (R-3m); the lattice parameters (a and c of hexagonal setting) and degree of cation mixing and R-factor showed increased fluorine content (x). Cycle retention of 0.5Li(2)MnO(3) center dot 0.5LiNi(1/3)Co(1/3)Mn(1/3)O(2-x)F(x) (x = 0, 0.1, 0.2) high porous nanofibers exhibited 58.1, 62.6, and 64.2%, respectively. At high C-rate (5C), 0.5Li(2)MnO(3) center dot 0.5LiNi(1/3)Co(1/3)Mn(1/3)O(1.8)F(0.2) showed highest discharge capacity. It suggests F-substitution of 0.2 mol cathode material is more stable than pristine cathode material.