Al^(3+)、Cl^-掺杂LiMn_2O_4的电化学性能研究

Study on the Electrochemical Performance of LiMn_2O_4 Doped with Al^(3+) and Cl^- Ions

采用以柠檬酸为配位剂的溶胶-凝胶法制备了复合掺杂Al、Cl两种元素的锂离子电池正极材料LiMn2-xAlxO4-yCly.采用X射线衍射、透射电子显微镜及充放电循环等方法分析研究了不同掺杂量对材料结构、粒径及电化学性能的影响.结果表明,制备的样品具有良好的尖晶石结构,其中LiMn1.9Al0.1O3.9Cl0.1的高温(55℃)循环性能最佳,初始放电比容量为105.2 mAh/g,25次循环后容量仅衰减4.37%.显示Al-Cl复合掺杂能有效的改善尖晶石的高温电化学性能.

LiMn2-xAlxO4-yCly are synthesized by a sol-gel method using citric acid as a chelating agent. The effects of aluminium and chlorine quantity on the structure, particle size and electrochemical properties of LiMn2-xAlxO4-yCly are investigated by XRD, TEM and charge-discharge cycling. The results indicated that the samples have a spinel structure and sub-micron particle size. Among the five samples, LiMn1.9Al0.1O3. 9Cl0. 1 has the best electrochemical property. The initial discharge capacity is 107.5 mAh/g, and the rate of the capacity loss is only 4.56% after 25 cycles at elevated temperature（55℃）. The results showed that the electrochemical properties of spinel at elevated temperature can be improved effectively by simultaneous substitution of Al and Cl.