고밀도 고용량의 리튬 이차전지를 위한 Li1+x[M]1-XO2 (M=Ni0.2Co0.1Mn0.7, X=0.17, 0.19, 0.21) 의 합성 및 전기화학적 특성

Abstract

[M](OH)2 precursor based Li1+x[M]1-xO2 and [M]3O4 precursor based Li1+x[M]1-xO2 (M=Ni0.2, Co0.1, Mn0.7, x = 0.17, 0.19, 0.2) cathode materials have been synthesized via co-precipitation in N2 and air for rechargeable battery applications. An [M]3O4 based sample was observed to have a spherical morphology with an average particle size of approximately 7 ?m in diameter. In addition, lithiated powders ([M]3O4 based Li1.19[Ni0.2Co0.1Mn0.7]0.81O2) exhibited a higher tap density (2.0 g cc-1) when compared to [M](OH)2 based Li1.19[Ni0.2Co0.1Mn0.7]0.81O2 powders (1.5 g cc-1). An analysis of powder X-ray diffraction (XRD) patterns revealed that the powders possess an ?-NaFeO2 structure from the space group. A cathode material synthesized in air exhibited a higher initial discharge capacity of 263.3 mAh g-1 when compared to a cathode material synthesized in an N2 atmosphere (246.9 mAh g-1). Li-rich samples fabricated from the[Ni0.2Co0.1Mn0.7]3O4 precursor possessed a small primary particle size and a porous volume, both of which provide the structural foundation for a high discharge capacity. Two samples exhibited good cycling performances of 95% and 94.8% at 2.0 ? 4.6 V, respectively.