Synthesis of Layered-Structure LiMn1–xCrxO2 by the Pechini Method

LiMn1-xCrxO2 compounds with an α-NaFeO2 layer-type crystal structure have been prepared by the Pechini method. The effects of ethylene glycol (EG) content and calcination temperature on powder characteristics and electrochemical performance are evaluated. It is found that the homogeneity of the powder is increased by increasing the molar ratio of EG to citric acid, and a trace of MnO can be detected in the powder calcined below 800°C for 4 h. Compared with the ss-LiMn1-xCrxO2 powder (made by the solid-state reaction), the p-LiMn1-xCrxO2 compound (made by the Pechini method) yielded higher specific capacity for both charge and discharge, and the rate capability has been improved due to the smaller particle size and good homogeneity. The evolution of discharge curves with cycling shows that less additional spinel-type tetrahedral sites for Li formed during cycling of the p-LiMn1-xCrxO2 compound.