Study of structural, electric, and electrochemical properties and storage mechanism of Na doped LiFePO4 cathode materials

Abstract

Density functional theory (DFT) has been used to investigate the structural, electrochemical and electronic effects of the Na-doped Li site of the LiFePO4 cathode material. NaxLi1−xFePO4(x=0,0.25,0.5) materials are considered. The results of intercalation voltage are 3.79,3.28and3.52 for x=0,0.25,0.5 respectively. The electronic and thermal conductivity of Na0.5Li0.5FePO4 are the same as that of simple LiFePO4, with an exception at high temperature where the conductivities of LiFePO4 are greater than that of the others. The Na0.25Li0.75FePO4 material show a small electronic conductivity compared to the others.