Sol - Gel Synthesis of Normal Spinel LiMn_2O_4 and Its Characteristics

摘要

Normal spinel LiMn_2O_4 was synthesized by sol - gel method using lithium nitrate, manganese nitrate, citric acid and ethylene glycol as raw materials. LiMn_2O_4 was characterized by XRD, TG - DTA, IR, SEM and AAS. The optimum conditions for the synthesis were explored. Citric acid and ethylene glycol were mixed with molar ratio of 0.25, and the mixture was esterified at 140 deg C for 4 hours. Then lithium nitrate and manganese nitrate were added with molar ratio of 0.6. In the system, the total molar of cations was equal to that of citric acid. At last, reflux the system at 105 deg C for 2 hours. Dried gel was fired at 600 deg C for 8 hours. Particle diameters of raw product were about 100 nm mainly. Further research shows that lithium ion of LiMn_2O_4 is easy to be extracted, and normal spinel lambda - MnO_2 can be obtained after lithium ion extraction.