First-principles investigation of the effects of Sb doping on the LiNiO2

First-principles calculations have been carried out to investigate the effects of Sb doping on the LiNiO2. It is found that crystal lattice parameters of the Sb-doped LiNiO2 increase with the increasing doping concentration of Sb. In order to properly assess the difficulty of Sb doping in the LiNiO2, the formation energies of SbxNi12-xO24(x=1,2,3) are firstly obtained according to the elemental chemical potentials determined by the phase stability conditions. Calculated formation energies indicate that the growth conditions of Sb2O5-rich, O-rich and Ni-rich contribute to the formation of SbxNi12-xO24(x=1,2,3). Furthermore, Sb1Ni11O24, Sb2Ni10O24 and Sb3Ni9O24 all have good thermodynamic stability if their growth conditions are reasonably adjusted. Besides, among Li12Ni12O24, Li12SbNi11O24, Li12Sb2Ni10O24 and Li12Sb3Ni9O24, Li12Sb2N10O24 has the smallest ratio of volume change and the highest theoretical average intercalation voltage during Li ion lithiation/delithiation process. Therefore, electronic structures of Li12Ni12O24 and Li12Sb2Ni10O24 are further analyzed. The calculated results demonstrate that Li12Sb2Ni10O24 has better stability and conductivity than Li12Ni12O24. Moreover, in the Li12Sb2Ni10O24, the electrostatic interaction between Li+ and Ni-O layers reduces compared with LiNiO2, which suggests that the diffusion ability of Li can be improved by Sb doping. Moreover, Li12Sb2Ni10O24 has better electro-chemical properties than LiNiO2. (C) 2016 Elsevier Inc. All rights reserved.