【摘要】 采用溶胶 凝胶法合成了锂离子电池正极材料LiMn2O4·研究了干凝胶制备锰酸锂的机理·由于干凝胶燃烧时生成的产物颗粒很细,燃烧过程中就有大量的锰酸锂生成,剩下的Mn3O4和Li2O2在300℃左右已完全转化为锰酸锂,大大降低了合成温度·通过对700℃合成的锰酸锂XRD分析表明,样品的衍射峰峰形尖锐,晶型发育良好·考察了pH值对合成样品粒度及电化学性能的影响,SEM分析表明,随pH值增加,所得溶胶制备的锰酸锂电化学容量增加,当pH=6 0时合成样品颗粒分布均匀,达到亚微米级·以0 1C的电流、电压范围3 30～4 35V充放电测试表明,该条件下合成的样品初始放电容量为121.0mAh·g-1,显示出良好的电化学性能·更多还原

【Abstract】 The spinel LiMn₂O₄ for lithium-ion battery was prepared by sol-gel method using Mn（Ac）₂·4H₂O, （AC）Li·2H₂O and harmless low-molecule citric acid as raw materials. The mechanism of synthesizing LiMn₂O₄ with dry gel was found by TGA-DTA analysis at different heating rates. In the process of dry gel burning, large quantity of the LiMn₂O₄ were formed because of the small grain size of the products Mn₃O₄ and Li₂O₂ resulting from burning, and the residual Mn₃O₄ and Li₂O₂ reacted completely at about 300?℃, thus lowering greatly the synthesizing temperature. XRD pattern of the LiMn₂O₄ showed that the product samples are all of a pure phase with spinel-type structure, sharp peak and perfect crystalline. Investigating the effect of pH values on the grain size and electrochemical property of samples, the SEM analysis showed that the electrochemical capacity of the LiMn₂O₄ samples increases with the increasing pH value, of which the grain size distribution is uniform at a sub-micron level if pH value is 6.0. The charge/discharge testing result at 10% current of initial discharge capacity and 3.30～4.35?V showed that the initial discharge capacity of the synthesized samples is 121.0?mAh/g. It implies a good electrochemical property.更多还原