Comparison of structure and electrochemistry of Al- and Fe-doped LiNi1/3Co1/3Mn1/3O2

LiNi1/3Co1/3−xMxMn1/3O2 (M = Fe and Al; x = 0, 1/20, 1/9 and 1/6) have been synthesized by firing the co-precipitates of metal hydroxides. The impacts of Fe and Al doping on the structure and electrochemical performances of LiNi1/3Co1/3Mn1/3O2 are compared by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and galvanostatic charge/discharge test as cathode materials for lithium ion batteries. These materials keep the same layered structure as the LiNi1/3Co1/3Mn1/3O2 host. It is found that Fe- and Al-doped LiNi1/3Co1/3Mn1/3O2 show different characteristics in lattice parameter and cycling voltage plateau with increasing dopant dose. More interestingly, low Al doping (x < 1/20) improves the structural stability while Fe doping does not have such effect even at low Fe content.