Synthesis and electrochemical performance of LiCr _x Mn _2-xO₄(x=0,0.02,0.05,0.08,0.10) powders by ultrasonic coprecipitation

LiCr _x Mn_2-x O₄(x=0, 0.02, 0.05, 0.08, 0.10) compounds with a spinel crystal structure have been prepared by a novel ultrasonic co-precipitation method. The effects of the calcination temperature and the citric acid-to-metal ion molar ratio (R) on powder characteristics and electrochemical performance are evaluated. It is found that the optimum R and sintering temperature for LiCr _x Mn_2-x O₄ materials by the ultrasonic co-precipitation method are R= 5/6 and 800°C, respectively. The calcined powders are loosely bound agglomerates of abnormally coarsened particles with a narrow range of particle sizes. The effect of Cr doping was also explored. Electrochemical studies show that optimum materials synthesized by the ultrasonic co-precipitation method demonstrate good cycling performance.