富锂层状正极材料Li2Mn1-xTixO3的合成及电化学性能  

Syntheses and Electrochemical Characterization of Li-Rich Li_2Mn_(1-x)Ti_xO_3 Layered Materials Used for Lithium Ion Batteries

作　　者：熊礼龙[1,2] 肖翔[1] 徐友龙[1,2] 王继生[1] 

机构地区：[1]电子陶瓷与器件教育部重点实验室,西安交通大学,西安710049 [2]国际电介质研究中心,西安交通大学,西安710049

出　　处：《无机化学学报》2017年第2期269-275,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21203145)资助项目

摘　　要：应用简单的高温固相烧结法合成了Ti掺杂改性的Li_2MnO_3材料。电子扫描显微镜、X射线衍射以及X射线光电子能谱分析表明Ti元素取代Mn离子掺入到Li_2MnO_3晶格中,且掺杂能有效地抑制一次颗粒的团聚。电化学阻抗和恒流充放电测试结果表明,在2.0~4.6 V的电压窗口下,掺杂改性的样品Li_2Mn_(0.97)Ti_(0.03)O_3的首圈放电比容量达到209 m Ah·g^(-1),库仑效率为99.5%,循环40圈后容量保持率为94%;当电流密度增大到400 m A·g^(-1)时,掺杂改性的样品仍然可以放出120 m Ah·g^(-1)比容量,远高于同等电流密度下未掺杂的Li_2MnO_3原粉的比容量(52 m Ah·g^(-1))。Ti掺杂可有效地改善Li_2MnO_3的循环稳定性和倍率性能,有利于促进该材料的商业化应用。Ti-doped Li2MnO3 is synthesized by a conventional solid-state reaction. Scanning electron microscopy, X-ray diffraction and X-ray photoelectric spectroscopy analyses indicate Ti is successfully doped into Li2MnO3 structure and the doping could suppress agglomeration of primary particlesis efficiently. Electrochemical impedance spectroscopy and galvanostatic charge/discharge results show that, in the voltage window of 2.0~4.6 V （vs Li/Li＋）, doped sample Li2Mn0.97Ti0.03O3 delivers an initial discharge capacity of 209 mAh·g^-1 with 99.5% coulombic efficiency; after 40 cycles the capacity retention is 94%. Even the current density increases to 400 mA·g^-1, the doped sample could still deliver 120 mAh·g^-1 capacity, which is more than twice of that of undoped Li2MnO3 （52 mAh·g^-1）. Ti-doped Li2MnO3 show greatly improved cycling stability and rate performance, which is beneficial for promoting the commercial application of Li2MnO3 material.

关 键 词：锂离子电池 正极材料 掺杂 循环稳定性 倍率性能 

分 类 号：O614.111[理学—无机化学] O614.411[理学—化学]