Effects of metal ion sources on synthesis and electrochemical performance of spinel LiMn2O4 using tartaric acid gel process

The effect of lithium and manganese ions on the synthesis, phase purity, and electrochemical properties of tartaric acid gel processed lithium manganese oxide spinel were investigated. The poor bonding between both lithium and manganese ions with tartaric acid was shown by the FT-IR analysis when lithium nitrate and/or manganese nitrate were used as sources. Li2MnO3 and Mn2O3 impurities formed in addition to lithium manganese oxides when nitrate salts were used as the sources. When acetate salts were used as sources for the lithium and manganese ions, single-phase LiMn2O4 was obtained. These results indicate that homogeneous bonding between acetate salt and tartaric acid was formed. The capacity of single-phase LiMn2O4 calcined at 500degreesC was 117 mAh/g which was much higher than those containing Mn2O3 and Li2MnO3 impurity compounds. Thus, sources of lithium and manganese ions play an important role in the synthesis and electrochemical behaviors of lithium manganese oxide spinel. (C) 2002 Elsevier Science.