Magnetic, electronic and structural properties of: LiFePO₄ : ab-initio study

In this work we carry out the theoretical study of the structural, electronic and magnetic properties of Li(Mn_yFe_1-y)PO₄ for different concentrations of manganese (Mn). This compound is of great technological interest due to its use as a cathode in rechargeable lithium ion presenting properties such as low production cost, high degree of recyclability, and a stable structure under extreme conditions. The Study was performed with PWscf code, which allows first principle calculations within the formalism of Density Functional Theory using the generalized gradient approximation (GGA) and local density approximation (LDA+U). Structural properties such as lattice parameter, bulk modulus, volume were calculated for different concentrations of Mn in the compound. Forces between atoms were analyzed and adjusted according to Murnaghan approximation. Electronic properties such as density of states and band structure are also studied for GGA and LDA+U approaches. It was confirmed that GGA underestimates the band gap value while LDA+U gives a closer value to the experimental data. Finally, a linear relation between the total magnetic moment and Mn concentration was found for the compound.