Retarded layered-to-spinel phase transition in structure reinforced birnessite with high Li content  

有效抑制层状-尖晶石相变的高锂含量、结构稳定的水钠锰矿电极材料

作　　者：Xiaohui Zhu Qiuying Xia Xinyi Liu Qinghua Zhang Jing Xu Baowei Lin Shuang Li Yuhang Zhuang Ce Qiu Liang Xue Lin Gu Hui Xia 朱晓辉;夏求应;刘馨逸;张庆华;徐璟;林宝伟;李爽;庄宇航;邱策;薛亮;谷林;夏晖(School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;Herbert Gleiter Institute of Nanoscience,Nanjing University of Science and Technology,Nanjing 210094,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China [2]Herbert Gleiter Institute of Nanoscience,Nanjing University of Science and Technology,Nanjing 210094,China [3]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Science Bulletin》2021年第3期219-224,M0003,共7页科学通报（英文版）

基　　金：the National Natural Science Foundation of China(51972174,51772154,and 51702164);Natural Science Foundation of Jiangsu Province(BK20170036 and BK20170844);the Six Talent Peaks Project of Jiangsu Province(2018-XNY-025)。

摘　　要：Layered lithium manganese-rich oxides are promising cathode materials for lithium-ion batteries(LIBs),due to the low-cost,abundant manganese source,and large theoretical capacity.However,these layered lithium manganese-rich oxides,e.g.,monoclinic-LiMn0_(2),suffer from poor cycle performance and rate performance because of fast structural degradation with the irreversible layered-to-spinel phase transition and sluggish electrode kinetics during cycling[1,2].层状LiMnO2在第一个充电过程即可发生层状向尖晶石结构的转变,使得该正极材料在锂离子电池中无法得到实际应用.Li-Birnessite具有较大的层间距,且层间结晶水作为层间支撑,可以缓解充放电过程中层状向尖晶石的结构转变,从而提高其结构稳定性.然而,先前报道的Li-Birnessite通常具有较低Li含量以及Mn空位、无序乱排等结构缺陷,导致层状到尖晶石的相变无法得到有效抑制.本文通过Mn_(3)O_(4)的电化学氧化,再经水热Li^(+)/Na^(+)离子交换制备了一种具有高Li含量、高度有序的层状结构和较大层间距(~6.6A)的Li_(0.73)MnO_(2)·0.26H_(2)O正极材料.该电极充放电循环100次后,其容量保持率为92.2%,未发现尖晶石相存在.即使经过200次循环后,电极样品中只检测到有少量的尖晶石相存在,表明高Li含量和高度结构有序可以有效延缓水钠锰矿材料中的层状向尖晶石相转变.该工作为锂离子电池用Mn基层状材料的结构设计提供了新思路.

关 键 词：锂离子电池 层状LIMNO2 尖晶石相 正极材料 充电过程 充放电过程 层状材料 充放电循环 

分 类 号：TM912[电气工程—电力电子与电力传动]