Structural and electronic properties of non-metal doping in Li2FePO4F compound: spin density functional theory

I comparatively determine the structural and electronic properties of Li2FePO4F compounds with F substituted by Cl, Br and I atom using the spin density functional theory with Perdew-Burke-Ernzerhof generalised gradient approximation (GGA + U). The lattice parameters and volumes are improved by the dopants because of the greater atomic radius in dopants. Non-metal doping in Li2FePO4F reduces the band gap. When doping, Li ion can mobile efficiently because of the reduced ionic character and increased Li-Dopant bond lengths. As the computations, Li2FePO4(F, I) material possesses the highest electronic conductivity among all compounds. Finally, this non-metal doping research provides the detailed information for understanding the enhancement mechanism and assists more broadly in the material design for the wider class of fluorophosphates cathodes in Li-ion rechargeable batteries.