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

Abstract

The electronic and structural characteristics of FePSe3 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 FePSe3 and Ca doped FePSe3 alloys were assessed in terms of density of states (DOS) and band structure. At the Fermi level, the electronic states of alloys such as, Fe1Mg1P2Se6, Fe2P2Se5Mg1, Fe1Ca1P2Se6 and Fe2P2Se5Ca1 suggest that they are non-metallic. While the electronic states of Fe2P1Mg1Se6 and Fe2P1Ca1Se6 are metallic. The alloys Fe1Mg1P2Se6 and Fe1Ca1P2Se6 have robust diffusion, according to structural analysis. Because of its shorter bond length of 2.67 Å, the Fe1Mg1P2Se6 alloy has the strongest ion diffusion into FePSe3. It also has the highest band gap of 1.62 eV, followed by Fe1Ca1P2Se6 at 1.50 eV. As seen in the alloys Fe1Mg1P2Se6 and Fe1Ca1P2Se6, the divalent ions Mg2+/Ca2+ prefer insertion into the Fe site of FePSe3. These alloys are potential materials for Magnesium ion batteries (MIB) and Calcium ion batteries (CIB) due to their stability and electronic conductivity.