(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 通过X射线衍射(XRD)、扫描电镜(SEM)、粒度分析以及充放电性能测试对固相烧结法制备的LiCoxMn2−xO4(x=0，0.05，0.10，0.15，0.20)结构、形貌进行表征，并对电化学性质进行研究。研究结果表明，LiCoxMn2−xO4(x=0，0.05，0.10，0.15，0.20)均为单一尖晶石结构，无杂相存在；晶格常数随着掺杂量x的增大而线性减小；钴掺杂有助于LiCoxMn2−xO4晶体更规则地生长，使一次颗粒呈现八面体结构；掺钴对LiCoxMn2−xO4的平均粒径无明显影响；纯LiMn2O4在循环过种中容量衰减快，钴掺杂明显地改善了LiMn2O4充放电循环性能，且大电流放电能力提高；随着掺钴量的提高，大电流充放电性能与循环过程中容量的保持率也提高。
关键字: 锂离子电池；锰酸锂；尖晶石；钴掺杂；正极材料
Co-doping lithium manganese oxide
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Properties of LiCoxMn2−xO4(x=0, 0.05, 0.10, 0.15, 0.20) synthesized by solid state reaction were studied in the aspects of structure, and electrochemistry using X-ray diffractometry(XRD), scanning electronic microscopy(SEM), distribution of particle size and charge-discharge measurement. The results show that the pure phase exists with the same structure as spinel to all samples with and without cobalt-doping, not containing other minor impurity. The linear relationship of lattice parameter and Co-doping amount for LiCoxMn2−xO4 is determined by powder XRD refinement. The more regular octahedral morphology of primary particles is observed under scanning electron microscope, which indicates the doping of cobalt is beneficial to the growth of crystal. However, the particle size is not affected by cobalt doping. The cycleability and the rate capability are greatly improved by the introduction of cobalt to the lattice. The more the amount of manganese is substituted by cobalt, the higher the capacity retention and more excellent rate capability are obtained.
Key words: lithium ion batteries; lithium manganese oxide; spinel; cobalt doping; cathode materials
