Electrochemical characterization of Li2MnO3-Li[Ni1/3Co1/3Mn1/3]O-2-LiNiO2 cathode synthesized via co-precipitation for lithium secondary batteries

초록

Various compositions of the xLi(2)MnO(3)-yLi[Ni1/3Co1/3Mn1/3]O-2-zLiNiO(2) electrode system were synthesized using metal oxide precursor by adopting co-precipitation method. XRD revealed that the prepared cathode materials possess alpha-NaFeO2 structure with R3m space group. Scanning electron micrographs demonstrated the morphology of all the synthesized samples, wherein spherical agglomerates with size of 5-10 mu m have been acknowledged. Among the tested samples, Li[Li0.18Ni0.220Co0.120Mn0.480]O-2 shows the excellent capacity retention (95.6%) in the voltage range of 2.0-4.6 V and the better rate capability than the other samples. But. on the other hand, Li[Li0.20Ni0.133Co0.133Mn0.534]O-2 (x = 0.6, y = 0.4 and z = 0.0) shows the highest discharge capacity. However, the capacity retention of the material at 50 mA g(-1) is lower than that of Li[Li0.18Ni0.220Co0.120Mn0.480]O-2. Furthermore, the capacity retention at 1250 mA g(-1) is only 42.6% of the capacity obtained at 20 mA g(-1).

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