Effect of la dopant on the structure and electrochemical properties of LiCoO₂

Abstract

The cathode material LiCo_1−xLa_xO₂(x=0, 0.01, 0.02, 0.05) for Li-ion battery was prepared in solid phase. Effects of La dopant on the structure were analyzed by X-ray diffraction, and the morphology of the samples was observed by scanning electron microscopy. The results show that the structure of LiCoO₂ becomes more and more non-perfect with the increasing content of La and some impurity peaks appear in the XRD pattern when the La content reaches 0.05. Meanwhile, a high synthesis temperature is advantageous to the intact and unitary compound. The initial discharge capacity of doped material containing La (x=0.01) synthesized at 900 °C reaches 160 mAh/g by charge-discharge test, which prior to that of non-doped material synthesized under the same condition. However, the increasing La content deteriorates the cycling performance. Therefore, the appropriate content of La is 0.01 and the optimum synthesis temperature is 900°C.

Keywords

Li-ion battery / cathode materials / LiCoO₂ / doping / rate earth

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