Study on the electronic structures, mechanical properties, and lithium-ion migration of Mo-N co-doped LiFePO4 by first-principles

Abstract

This article uses first principles to calculate the mechanical stability, electronic structure, and electrochemical performance of Mo-N co-doped LiFePO4. The formation energy of Mo-N co-doped LiFePO4 indicates excellent thermodynamic stability. Electron density of states and effective electron mass calculations demonstrate that co-doping can enhance the electrical conductivity of the system. The de-lithium calculations show that doping the material with Mo-N enhances its cyclic stability. Elastic constant calculations demonstrate that the dopants can enhance the shear resistance and de-lithium capacity of LiFePO4. Additionally, investigations on the material's anisotropy have revealed that Mo-N co-doping tends to promote isotropy in the material. The decrease in the migration barrier of the doped system indicates that co-doping increases the migration rate of lithium ions, thereby enhancing the rate performance of the material.