Doping FePSe3 with Mg and Ca ions: A Density Functional Theory Study

Abstract The electronic and structural characteristics of FePSe 3 doped with Mg and Ca were investigated using density functional theory (DFT) computations as implemented in the Quantum Espresso simulation package. The electronic conductivities of several Mg doped FePSe 3 and Ca doped FePSe 3 alloys were assessed in terms of density of states (DOS) and band structure. At the Fermi level, the electronic states of alloys such as, Fe 1 Mg 1 P 2 Se 6 , Fe 2 P 2 Se 5 Mg 1 , Fe 1 Ca 1 P 2 Se 6 and Fe 2 P 2 Se 5 Ca 1 suggest that they are non-metallic. While the electronic states of Fe 2 P 1 Mg 1 Se 6 and Fe 2 P 1 Ca 1 Se 6 are metallic. The alloys Fe 1 Mg 1 P 2 Se 6 and Fe 1 Ca 1 P 2 Se 6 have robust diffusion, according to structural analysis. Because of its shorter bond length of 2.67 Å, the Fe 1 Mg 1 P 2 Se 6 alloy has the strongest ion diffusion into FePSe 3 . It also has the highest band gap of 1.62 eV, followed by Fe 1 Ca 1 P 2 Se 6 at 1.50 eV. As seen in the alloys Fe 1 Mg 1 P 2 Se 6 and Fe 1 Ca 1 P 2 Se 6 , the divalent ions Mg 2+ /Ca 2+ prefer insertion into the Fe site of FePSe 3 . These alloys are potential materials for Magnesium ion batteries (MIB) and Calcium ion batteries (CIB) due to their stability and electronic conductivity.