Study On Preparation And Electrochemical Properties Of LiMn₂O₄

Acetic acid lithium and acetic acid manganese were used as as raw materials to prepare spinel structure LiMn₂O₄ adopting the citric acid complexing method. Thermal decomposition of precursor was investigated by differential scanning calorimetry and thermogravimetry (DSC-TG). The effects of sintering temperature and component on purity and structure of product were examined by X- ray diffraction analysis. The effect of atom location confused degree in LiMn₂O₄ on the intensity of X-ray diffraction peak under different conditions was analyzed in theory. The average chemical valence of the manganese ion was measured through inductively coupled plasma emission spectral analysis. The micrograph of product was observed by scanning electron microscope (SEM).The effect rule and mechanism of voltage and confused atom location on properties of cathode materials during charging and discharging was discussed. Electrochemical property of rich lithium spinel Li₄Mn₅O₁₂ was studied. Capacity decaying mechanism of LiMn₂O₄ was also discussed. The result show that The temperature range of precursor decomposition is large during heating adopting acetic acid lithium and acetic acid manganese as raw materials. Meanwhile, the speed of weight loss is slow and reaction is steady, which is favorable for the control of quality. High purity spinel LiMn₂O₄ can be prepared at the temperature between 450⁷50℃. And with the temperature increasing, the crystal constant and size of particle of LiMn₂O₄ increase and the purity do not obviously change. The purity is above 90% and has better quality stabilities. The temperature has influence on confused degree of atom location in LiMn₂O₄. With the increase of temperature, anti-spinel type confused degree reduce, but 16c type raise. According to mole ratio of lithium and manganese 1:1, rich lithium spinel...