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Corresponding Author

Xue-Ping GAO(xpgao@nankai.edu.cn)

Abstract

The Li(Li0.22Ni0.17Mn0.61)O2 was prepared with oxalic co-precipitation and coated with an YF3 layer by a chemical deposition method. The as-prepared and YF3-coated Li-rich materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results demonstrate that the as-prepared and YF3-coated Li(Li0.22Ni0.17Mn0.61)O2 materials have a typical layered structure and are composed of sphere-like particles with a diameter of 100~200 nm. Galvanostatic charge-discharge tests show that the discharge capacity of the YF3-coated Li(Li0.22Ni0.17Mn0.61)O2 is obviously improved. At the low current density of 60 mA.g-1, the discharge capacity reaches 240 mAh.g-1, and remains 220 mAh.g-1 after 30 cycles. At the high current density of 1500 mA.g-1, the discharge capacity still keeps 150 mAh.g-1, showing an excellent high-rate capability. Electrochemical impedance spectra (EIS) reveal that the YF3-coated Li(Li0.22Ni0.17Mn0.61)O2 shows lower charge-transfer resistance and diffusion impedance as compared with the as-prepared Li(Li0.22Ni0.17Mn0.61)O2.

Graphical Abstract

Keywords

Li-ion batteries, cathode material, Li-rich layered oxides, YF3-coated, high-rate capability

Publication Date

2012-08-28

Online Available Date

2012-02-21

Revised Date

2012-02-16

Received Date

2011-11-24

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