Surface element segregation and electrical conductivity of lithium layered transition-metal oxide cathode materials
Journal article, 2018

Surface element segregation and electric conductivity are critical in determining lithium storage ability of given cathode materials, which are poorly understood and not correlated with the structure and overall performance. Here, layered lithium transition-metal oxides, one of the state-of-the-art cathode materials for lithium ion batteries are chosen to study. A serial of LiNixCo1-2xMnxO2 samples were prepared via a solid state reaction and subsequently characterized by XRD in conjunction with structural refinement, XPS depth profiling, and AC impedance spectroscopy. Slightly different expansion rates are observed for lattice parameters (a and c/3) with varying of Ni content, which is attributed to the increase of average metalion radius and an increase of e(g) electron that enhances the columbic repulsion between transition metal and oxygen atoms. XPS depth profiling results show that surface composition is significantly deviated from bulk, in which Ni and Mn atoms tend to enrich in the surface region, while Co element is relatively deficient. Further, surface element segregation is alleviated by the increase of Ni/Mn content. Moreover, increasing the Ni/Mn content also raises the activation energy of bulk conduction.



electrochemical performance





Layered transition-metal oxides

li-ion batteries

Cathode materials






G. H. Li

Chinese Academy of Sciences

Qi Li

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

L. P. Li

Jilin University

Chinese Academy of Sciences

J. M. Fan

Chinese Academy of Sciences

Q. Q. Ge

Thermo Fisher Scientific

D. J. Xie

Chinese Academy of Sciences

J. Zheng

Chinese Academy of Sciences

G. S. Li

Jilin University

Applied Surface Science

0169-4332 (ISSN)

Vol. 427 226-232

Subject Categories

Inorganic Chemistry

Materials Chemistry



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