| The latest developments of various kinds of cathode materials for lithium ion batteries have been reviewed in this paper, which emphasizes on the mechanism and solution of capacity fading of cathode material LiMn2O4.First, on the base of former research, the amount of critic acid was studied, the best amount of critic acid and the total amount of Li+ and Mn2+ was in the ratio of 1.2. Samples synthesized under this condition have good spinel structure and electrochemical property. Its initial capacity is 102.8mAh/g, the ratio of capacity loss is 2.54%.Cation-doping spinel LiMn2-xMxO4(M=Li,Co,Al,Mo,Y,La,Nd) and anion-doping spinel LiMn2O4-yQy were then synthesized by the method introduced previously, the best amount of the cation doped into spinel was fixed. The results of the measurements show that the samples have good spinel structure, and the electrochemical property can be elevated on a certain extent.According to the results of single-doping research, we prepared multi-doping spinel LiMn2-xMxO4-yQy(M=Co,Al,La,Y,Nd; Q=F,Cl). The impact on structure, particle size and electrochemical properties of the samples were investigated by the means including XRD, TEM and charge-discharge cycling. The results show that these samples have good spinel structure, and the electrochemical properties of them are improved obviously. LiMn2-xCoxO4-yFy and LiMn2-xAlxO4-yCly samples were prepared, LiMn1.88Co0.12O3.8F0.2 and LiMn1.9Al0.1O3.9Cl0.1 had the best properties, their initial specific discharge capacity were 107.5mAh/g and 105.2mAh/g, and the capacity loss of them at 55℃were 4.56% and 4.37%, respectively. At last, samples doped with thulium and F- were prepared, the samples were LiMn1.99Y0.01O3.9F0.1, LiMn1.99Nd0.01O3.9F0.1 and LiMn1.99La0.01O3.9F0.1, the initial capacity of them were 113.5mAh/g, 113.6mAh/g and 108.5mAh/g, and the capacity loss were 7.58%, 2.37% and 3.69%, respectively.According to the results showed in this abstract, we believe that ion-doping, especially multi-doping is a good means of properties improvement of LiMn2O4. In the furture research, multi-doping which import more than three kinds of ion into spinel LiMn2O4 can be carried out.
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