First-principle investigations of N doping in LiFePO4

N doped LiFePO4 has been investigated by using first-principle calculations with the projector augmented wave (PAW) method. The effect of N doping on its crystal structure, charge distribution and transport properties have been studied within the Generalized Gradient Approximation (GGA)+U framework. To maintain charge balance, the valence of the Fe nearest to N appears as Fe3+, and it will benefit for the hopping of electrons. The Elastic band method was used to calculate the activation energy for Li diffusion. N doping leads to slightly lower activation energy.