He Xiangming, Wang Jixian, Wang Li, Li Jianjun
Institute of Nuclear & New Energy Technology, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China.
Materials (Basel). 2016 Aug 5;9(8):661. doi: 10.3390/ma9080661.
An amorphous complex precursor with uniform Mn/Ni cation distribution is attempted for preparing a nano-structured layered Li-rich oxide (LiMnNiO₂)cathode material, using diethylenetriaminepentaacetic acid (DTPA) as a chelating agent. The materials are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical tests. The crystal structure of Li-rich materials is found to be closely related to synthesis temperature. As-obtained nano materials sintered at 850 °C for 10 h show an average size of 200 nm with a single crystal phase and good crystallinity. At a current density of 20 mA·g, the specific discharge capacity reaches 221 mAh·g for the first cycle and the capacity retention is 81% over 50 cycles. Even at a current density of 1000 mA·g, the capacity is as high as 118 mAh·g. The enhanced rate capability can be ascribed to the nano-sized morphology and good crystal structure.
尝试使用二乙烯三胺五乙酸（DTPA）作为螯合剂，制备一种具有均匀Mn/Ni阳离子分布的无定形复合前驱体，以用于制备纳米结构的富锂层状氧化物（LiMnNiO₂）正极材料。通过粉末X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和电化学测试对材料进行表征。发现富锂材料的晶体结构与合成温度密切相关。在850℃下烧结10小时得到的纳米材料平均尺寸为200nm，具有单晶相和良好的结晶度。在20 mA·g的电流密度下，首次循环的比放电容量达到221 mAh·g，在50次循环后的容量保持率为81%。即使在1000 mA·g的电流密度下，容量仍高达118 mAh·g。倍率性能的提高可归因于纳米尺寸的形态和良好的晶体结构。
