Abstract:LiMn2-xMxO4-yFy(x=0.05; y=0.05; M=Al, Co, Cr and Mg, separately), as the cathode material, was synthesized by the method of high temperature solid-state reaction in laboratory. The results of charge-discharge test show that the properties of LiMn1.95M0.05O3.95F0.05(M= Al, Mg) are obviously superior to those of LiMn2O4. Through the condition experiments on sintering temperature, it is found that the materials present the integrate crystal structure and favorable cycle performance at 800 ℃. The research on the effects of different Mg2+ sources on the properties of LiMn2-xMgxO4-yFy shows that, with Mg(OH)2 and LiF as the reagents respectively offering Mg2+ and F−, LiMn1.95Mg0.05O3.95F0.05 synthesized has integrate crystal structure and its capacity hardly fades. The results of cyclic voltammetry indicate that the shape of two couples of redox peaks of the material synthesized by co-doping anti-electricity ions is more integrate and symmetrical than that of pure spinel LiMn2O4, which reveals that the co-doping material possesses preferable electrochemical reversibility.

Key words: Li-ion batteries; cathode material; LiMn2O4; Co-doping; anti-electricity ions; cycle performance