【作者】 林素英；

【导师】 童庆松；

【作者基本信息】 福建师范大学 ， 物理化学， 2004， 硕士

【摘要】 Li₄Mn₅O₁₂可在广泛的组成范围内嵌锂，理论比容量可达到163mAh／g。在充放电过程中，Li₄Mn₅O₁₂具有晶胞膨胀率较小，循环性能优秀，高容量利用率等优点。困难是难于合成纯Li₄Mn₅O₁₂并充分体现其循环性能。 针对以上情况，本文综合考察了Li₄Mn₅O₁₂的研究进展，尝试以Li₄Mn₅O₁₂正极材料为目标产物，比较了不同原料配比、烧结方式及温度对材料性能的影响，采用XRD、FTIR、CV、SEM、TG-DTA等手段从合成方法、电化学性能等方面对锂锰氧化物Li₄Mn₅O₁₂正极材料进行了系统研究。建立并优化了以柠檬酸，EDTA为螯合剂的复合络合法制备前驱体，微波与固相烧结结合的新方法。合成出颗粒尺寸为0.3-0.4μm左右、在20-700℃热稳定性比较好的Li₄Mn₅O₁₂正极材料。将此正极材料组装成纽扣电池，先大电流再小电流充放电，样品在38循环时仍然有155mAh／g的放电容量，证明此正极材料具有良好的电化学性能。存放实验证明其存放性能也很好。更多还原

【Abstract】 Li4MnsO12 can be inserted and deinserted lithium ion in extensive compose range, with the theory capacity of 163mAh/g. During charge-discharge cycle, the expandability of Li4Mn5O12 lattice is lower than other manganese oxides, thus the cycling performance is excellent with the high capacity utility efficiency. The problem is that it is difficult to synthesize pure Li4Mn5O12. In allusion to those, the different synthesis condition were studied ,such as different raw material proportion, sinter mode, temperature and so on. The as-synthesized samples were systemically measured by many modern experimental techniques such as the X-ray powder diffraction (XRD), Forier transform infrared spectroscopy (FT-IR), Cyclic voltammogram (CV), Scanning electron microscope (SEM), Thermogravimetric analysis-differential thermal analysis (TGA-DTA) charge-discharge and storage performance. Then the preparation condition is established. The optimized synthesis condition is that the precursor which using citric acid and EDTA as chelator. Was sintered by microwave pretreatment associating with low-temperature solid sintering, The Li4Mn5O12 with favourable electrochemical performance is synthesized in low-temperature sintering. The particle size is between 0.3-0.4 m, and it has excellent thermal stabilization performance at 20-700 C. During charge/discharge in both big current and little current, the sample has 155mAh/g discharge capacity after 38 cycles, and its storable performance is very well.更多还原