Effect of C doping on the structural and electronic properties of LiFePO₄: A first-principles investigation

Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we investigate the effect of C doping on the structural and electronic properties of LiFePO₄. The calculated formation energies indicate that C doped at O sites is energetically favored, and C dopants prefer to occupy O₃ sites. The band gap of the C doped material is much narrow than that of the undoped one, indicating better electronic conductive properties. To maintain charge balance, the valence of the Fe nearest to C appears as Fe³⁺, and it will be helpful to the hopping of electrons.