Doping of group IVB elements for nickel-rich cobalt-free cathodes  

作　　者：Shengnan Guo Xincheng Lei Jiayi Wang Jie Su Yingying Wang Xiaozhi Liu Pengxiang Ji Kangning Zhao Xuefeng Wang Lin Gu Zhenpeng Yao Dong Su 

机构地区：[1]National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Center of Hydrogen Science,Shanghai Jiao Tong University,Shanghai 200240,China [4]State Key Laboratory of Metal Matrix Composites,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [5]Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials,Department of Materials Science and Engineering,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Energy Chemistry》2023年第11期559-568,I0012,共11页能源化学(英文版)

基　　金：the funding support from the National Key Research and Development Program of China(2020YFB2007400);the National Natural Science Foundation of China(22209202,22075317);the Strategic Priority Research Program(B)(XDB33030200)of Chinese Academy of Sciences。

摘　　要：Hetero-element doping is a promising strategy to improve the cycling stability of nickel-rich cobalt-free cathodes for the next-generation high energy-density Li ion batteries.To make doping effective,it is important to understand the mechanism of how the dopants regulate the electronic band,lattice parameter adjusting,or hetero-phase formation to achieve high stability.In this study,we investigate LiNi_(0.9)Mn_(0.1)O_(2)cathodes doped with IVB grouping elements via multiple characterization techniques.By utilizing in situ XRD and TEM methods,we found that the stronger Ti-O bond effectively improves the cathode stability via a dual protection mechanism.Specifically,the bulk lattice of cathode is wellpreserved during cycling as a result of the suppressed H_(2)-H_(3)phase transition,while a in situ formed Ti-rich surface layer can prevent continuous surface degradation.As a result,the 5%Ti doped LiNi_(0.9)Mn_(0.1)O_(2)cathode exhibits a high capacity retention of 96%after 100 cycles.Whereas,despite IVB group elements Zr and Hf have stronger bonding energy with oxygen,their larger ionic radii actually impede their diffusion into the cathode,thereby they can not improve the cycling stability.Our findings uncover the functional origin of doped elements with their dynamic modification on cathode structure,providing mechanistic insights into the design of nickel-rich cobalt-free cathodes.

关 键 词：Li ion battery Layered cathode Cycling stability Doping effect In situXRD 

分 类 号：TB34[一般工业技术—材料科学与工程] TM912[电气工程—电力电子与电力传动]