First principles studies on the electronics structures of (Li1−x Me x )FePO4 (Me=Na and Be)

摘要: Based on density functional theory (DFT) of the first-principle for cathode materials lithium ion battery, electronic structures (Li1−xMex)FePO4 (Me=Na and Be, x=0–0.40) are calculated by plane wave pseudo-potential method using Cambridge serial total energy package (CASTEP) program. The results show that Li-site doping can improve conductivity enormously. Doping with Na has a noticeable effect improving its electrical conductivity. However, serious structural distortion will occur when is beyond 0.25. In view this, best less than Be an inconspicuous increasing good cyclical stability, but it cannot achieve as doped Na. Therefore we find middle ground between two proposals. Considering cost environmental protection, ideal to choose So this gives reasonable prediction improvement through in LiFePO4 material.