%0 Journal Article
%A Wang, Rui
%A Qian, Guoyu
%A Liu, Tongchao
%A Li, Maofan
%A Liu, Jiajie
%A Zhang, Bingkai
%A Zhu, Weiming
%A Li, Shuankui
%A Zhao, Wenguang
%A Yang, Wenyun
%A Ma, Xiaobai
%A Fu, Zhendong
%A Liu, Yuntao
%A Yang, Jinbo
%A Jin, Lei
%A Xiao, Yinguo
%A Pan, Feng
%T Tuning Li-enrichment in high-Ni layered oxide cathodes to optimize electrochemical performance for Li-ion battery
%J Nano energy
%V 62
%@ 2211-2855
%C Amsterdam [u.a.]
%I Elsevier
%M FZJ-2020-01995
%P 709 - 717
%D 2019
%X To understand what and how structural properties affect battery performance, and to optimize the structural properties accordingly are of crucial importance to improve the performance of cathode materials for advanced Li-ion batteries. Herein, we investigated the influence of Li-enrichment in Li1+x(Ni0.8Co0.2)1-xO2 transition metal (TM) oxide cathodes, obtained by sintering Ni0.8Co0.2(OH)2 precursor with different amount of Li sources. Compared with stoichiometric Li1+x(Ni0.8Co0.2)1-xO2 (i.e. x = 0, Li:TM = 1:1), the improvements of cycling stability and rate performance were observed in material with moderate degree of Li-enrichment with respect to TMs (i.e. x = 0.019, Li:TM = 1.04:1). Further increase in Li:TM ratio up to 1.07 diminishes the electrochemical performance. Multi-scale structural characterizations including neutron diffraction and aberration-corrected transmission electron microscopy measurements show that the Li-enrichment leads to a monotonical increase in both Li/Ni exchange ratio and Li slab space. Based on the results, we argue that, in material with moderate Li-enrichment, larger Li slab space can facilitate the diffusion of Li ions and a certain amount of Li/Ni disordering can also mitigate the contraction of layered structure, therefore resulting in an optimized electrochemical performance; while in material with excessive Li:TM ratio, the diffusion path can be partially blocked due to the presence of redundant Ni ions in Li layers.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000474636100076
%R 10.1016/j.nanoen.2019.05.089
%U https://juser.fz-juelich.de/record/875384