Abstract: The co-doping modified spinel LiMn_1.98Cr_0.02O_4-yCl_y(y=0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10) as the cathode for lithium ion battery were synthesized with high-temperature solid-state reaction method. X-ray diffraction were used to characterize the crystal structure of the produced materials. The effects of co-doping modification in stabilizing the crystal frame and improving the electrochemical properties were comparatively investigated in terms of crystal structure, charge and discharge capacity, cycle performance and rate performance. The investigation comes to the conclusions that the co-doping modified cathode materials held the high enough initial capacity and represented an excellent cycle performance as well. In addition, the rate performance was also improved obviously. Among the co-doped materials, the most outstanding general performance belongs to LiMn_1.98Cr_0.02O_3.96Cl_0.04 which showed an initial specific discharge capacity of more than 127 mA·h/g and kept 110 mA·h/g after 50 cycles.

Key words: Cathode material, Spinel, Co-doping, Cycle performance