Core-shell LiCoO2-MgO fibers for use as lithium ion batteries were prepared by co-electrospinning combined with a sol-gel process. The rheological properties and viscosity of the spinnable sols, and the pressures of the two sols during the co-electrospinning process were investigated, which had an obvious effect on the diameter and shell thickness of the core-shell fibers. The fibers had a highly crystalline LiCoO2 core composed of partially oriented nanocrystals and a poorly crystalline MgO shell. The cyclic voltammogram (CV) experiments indicated that the coaxial fiber electrode exhibited excellent reversibility, smaller impedance growth and preferable electrochemical properties with obvious improvement of cyclability compared to bare LiCoO2 fiber electrodes.