Enhanced electrochemical performance of La-doped Li-rich layered cathode material

A series of promising lithium-rich cathode materials with excellent electrochemical properties were successfully synthesized by calcining precursors and lithium salts. The structure, morphology, element valence state, cyclic voltammetry and electrochemical impedance were used to study the properties...

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Bibliographic Details
Published in:Journal of alloys and compounds 2020-12, Vol.848, p.156620, Article 156620
Main Authors: Wang, Meng, Chen, Lin, Liu, Meng, Chen, Yunbo, Gu, Yijie
Format: Article
Language:English
Subjects:
Cathodes
Diffusion coefficient
Diffusion layers
Discharge
Electrochemical analysis
Electrode materials
La doping
Layered-spinel hetero-structure
Lithium
Lithium ions
Lithium ions diffusion coefficient
Lithium-ion batteries
Lithium-rich cathode materials
Morphology
Properties (attributes)
Spinel
Valence
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Summary:A series of promising lithium-rich cathode materials with excellent electrochemical properties were successfully synthesized by calcining precursors and lithium salts. The structure, morphology, element valence state, cyclic voltammetry and electrochemical impedance were used to study the properties of the materials. The doped La3+ had great influence on the structure and electrochemical properties of the materials. XRD results displayed that La3+ was incorporated into the material lattice resulted in the formation of layered-spinel hetero-structure, the decrease of cation mixing and the expansion of c lattice parameter. The discharge capacity decreased after La3+ was doped into Li[Li0.2Mn0.54Ni0.13Co0.13]O2, which was due to La3+ was non-electrochemical active element did not participate in the electrical reaction. Although the discharge capacity was reduced after La3+ doping, the initial coulombic efficiency, cycling performance and rate capability were all improved. Among the prepared samples, Li[Li0.2Mn0.54Ni0.13Co0.125]La0.005O2 delivered the best electrochemical performance and highest lithium ions diffusion coefficient, which can be ascribed to its stable and ordered layered-spinel hetero-structure. [Display omitted] •La3+ with large radius boost the migration of Li+ by expanding c lattice parameter.•La3+ doping can stabilize the structure of lithium-rich cathode materials.•The introduced layered-spinel hetero-structure improves cycle and rate performance.•The spinel phase provides 3D diffusion channels and promote Li+ migration.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2020.156620