The spinel phases LiAl_yMn_(2-y)O_4 (y=0, 1/12, 1/9, 1/6, 1/3) and Li(Al,M)_(1/6)Mn_(11/6)O_4 (M=Cr, Co) as the cathode for rechargeable lithium batteries

摘要

In order to improve the cycle performance of LiMn_2O_4, the spinel phases LiAl_yMn_(2-y)O_4 (y=0, 1/12, 1/9, 1/6, 1/3) and Li(Al,M)_(1/6)Mn_(11/6)O_4 (M=Cr, Co) were prepared at 650degC for 24 h in air. By substituting, the cycle performance was improved at the expense of an initial capacity. For LiAl_(1/12)Cr_(1/12)Mn_(11/6)O_4, the capacity of the cell maintained 90% of the initial capacity at the 200th cycle. By substituting, the chemical diffusion coefficient lithium ion in the cathodes increased by one order of magnitude comparing with that of parent LiMn_2O_4. The phase transition due to the Jahn-Teller distortion caused by Mn~(3+) was suppressed in these partially substituted spinels.