Li 1.03 Co 0.10 Mn 1.90 F z O 4-z (z=0, 0.05, 0.10, 0.15 and 0.20) cathode materials were synthesized by solid-state reaction using Mn 2 O 3 , Li 2 CO 3 , Co 2 O 3 and LiF~as raw materials. The chemical compositions of Li 1.03 Co 0.1 Mn 1.9 F z O 4-z were examined by inductively coupled plasma (ICP) and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Li 1.03 Co 0.10 Mn 1.90 O 4 were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. It is found that the Li 1.03 Co 0.10 Mn 1.90 F z O 4-z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z≤0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount of F substitution for O element with Li + , Co 3+ improves discharge capacity and structure stability of the materials. The Li 1.03 Co 0.10 Mn 1.90 F 0.15 O 3.85 sample shows an initial discharge capacity of 111.0 mA·h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.