Fe-stabilized Li-rich layered Li1.2Mn0.56Ni0.16Co0.08O2 oxide as a high performance cathode for advanced lithium-ion batteries

Fe-doped Mn based Li rich cathode materials Li1.2Mn0.56Ni0.16Co0.08-xFexO2 (x = 0, 0.01, 0.03, 0.05, 0.08) have been successfully prepared by traditional sol-gel technology. XRD Rietveld refinement results show that pristine and Fe-doped Li rich cathodes have layered α-NaFeO2 structure. SEM indicates that all samples have similar morphologies with a homogeneous particle distribution. EDS mapping exhibits that Mn, Co, Ni, Fe, and O atoms are uniformly distributed on the surface of Fe-doped Li1.2Mn0.56Ni0.16Co0.08O2 the powder. Fe doped Li rich electrodes show high reversible capacities than the pristine Li1.2Mn0.56Ni0.16Co0.08O2 at a current density of 2 C rate. After 100 cycles, the reversible capacities of Li1.2Mn0.56Ni0.16Co0.08-xFexO2 (x = 0, 0.01, 0.03, 0.05 and 0.08) cathodes are 73.2, 75.2, 85.3, 104.7 and 74.8 mAh g−1, respectively. Especially, Li1.2Mn0.56Ni0.16Co0.03Fe0.05O2 cathodes shows the highest discharge capacity among all samples. Li1.2Mn0.56Ni0.16Co0.03Fe0.05O2 also shows larger discharge capacity than the pristine Li1.2Mn0.56Ni0.16Co0.08O2 at each cycle at 1 C rate and elevated temperature (55 °C). The increased discharge capacity and cycling performance at high current density and elevated temperature of Li1.2Mn0.56Ni0.16Co0.03O2 may be ascribed to the decreased charge transfer resistance, the enhanced Li-ion diffusion and the reduced electrode polarization.