First principles study on the performance of Sn&F double-doped LiCoO2 in lithium-ion batteries

The demand for LIBs using LiCoO2 as a cathode material with higher energy density and improved safety is urgent. We have carried out a theoretical investigation of Sn&F double-doped LiCoO2 using first-principles calculations. The Sn&F double-doped LiCoO2 system, LiCo0.96Sn0.04O0.98F0.02, was modelled using a 3 × 3 × 1 supercell of LiCoO2 containing a pair of Co-O vacancies, with one O atom and one Co atom replaced by F and Sn, respectively. Our study shows that Sn&F doping contributes to a reduction in volume variation and inhibits Co migration during delithiation. Furthermore, Sn&F doping is shown to reduce the average activation barrier for Li diffusion.