Influence of the exchange-correlation potential and magnetic properties on the Li2FeSiO4 cathode materials

Seen the interest in the application of the density-functional theory (DFT) calculations to reproduce the experimentally observed properties of the potential electrode materials, we consider the electronic structure, electrochemical properties, mechanical and thermodynamic properties of the Li(2)FeSiO(4 )compound using magnetic or non-magnetic gradient-corrected density-functional theory (GGA + SP, GGA) and magnetic or nonmagnetic DFT corrected for on-site Coulomb interactions (GGA + U + SP, GGA + U) to allow a direct comparison of the four methods. In terms of the structural characteristics, the non-magnetic scheme cannot correctly describe them, but magnetic scheme can. However, like in GGA + SP and GGA + U + SP method, the accuracy is different in the description of the microscopic details for different magnetic schemes. As for electrochemical and electronic properties, only GGA + U + SP results are in line with the experimental values due to the reset of the electronic structure. The results show that both enhanced localization and spin-polarized effects present in the GGA + U + SP approximation are essential to reproduce the experimentally observed properties of the polyanionic compounds. Furthermore, we found that the inductive effect of the exchange correlation potential and magnetic properties also has some effect on the thermodynamic properties of the polyanionic compounds.