Yttrium modified Ni-rich LiNi0.8Co0.1Mn0.1O2 with enhanced electrochemical performance as high energy density cathode material at 4.5 V high voltage

This work adopts an effective method to stabilize the structure of Ni-rich LiNi0.8Co0.1Mn0.1O2 with yttrium modifying. The results of XRD, EDS, HR-TEM and XPS tests verify that the yttrium modified materials integrate surface nanoscale LiYO2 coating and inner gradient Y3+ doping. TGA and DSC tests c...

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Bibliographic Details
Published in:Journal of alloys and compounds 2019-02, Vol.774, p.82-92
Main Authors: Zhang, Meiling, Zhao, Hongyuan, Tan, Ming, Liu, Jintao, Hu, Youzuo, Liu, Shanshan, Shu, Xiaohui, Li, Hao, Ran, Qiwen, Cai, Jingjing, Liu, Xingquan
Format: Article
Language:English
Subjects:
Gradient doping
High voltage
LiYO2
Ni-rich cathode
Yttrium modification
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Summary:This work adopts an effective method to stabilize the structure of Ni-rich LiNi0.8Co0.1Mn0.1O2 with yttrium modifying. The results of XRD, EDS, HR-TEM and XPS tests verify that the yttrium modified materials integrate surface nanoscale LiYO2 coating and inner gradient Y3+ doping. TGA and DSC tests confirm that yttrium modification can promote the thermal stability of LiNi0.8Co0.1Mn0.1O2 cathode material. The results of galvanostatic charge-discharge tests suggest that the 2 mol% yttrium modified sample can exhibit a superior cycling performance with initial discharge capacity of 189.4 mAh g−1 and outstanding capacity retention of 98.4% after 100 cycles at 2.8–4.5 V, which presents obvious enhancement compared with the 83.5% capacity retention of pristine sample. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests indicate that 2 mol % yttrium modifying significantly enhances the diffusion of Li+ ions (DLi+) and notably decreases the electrochemical polarization of electrodes. The surface Li-ion conductor LiYO2 coating layer as a surface protector inhibits the side reaction and the gradient Y3+ doping supports the crystal structure, which can show synergistic effect in enhancing the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 cathode material. •Yttrium modification strategy is firstly proposed to modify LiNi0.8Co0.1Mn0.1O2.•Yttrium modification integrate surface LiYO2 coating and inner gradient Y3+ doping.•Yttrium modification shows good synergistic effect of LiYO2 coating-Y3+ doping.•2 mol% yttrium modified LiNi0.8Co0.1Mn0.1O2 shows excellent cycling stability.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2018.09.281