Effects of Mg²⁺ and Ti⁴⁺ Doping on Performance of LiFePO₄ for Lithium-Ion Batteries

Stoichiometric Mg 2+ and Ti 4+ with different proportions were doped to prepare the LiFe 1-x-y Mg x Ti y PO 4 cathode materials by high temperature solid state method. The samples were investigated with XRD, SEM and charge/discharge measurements. Results show that doping of Mg 2+ and Ti 4+ distinctly changes the paticle sizes and morphologies, which leads to a improvement of electrochemical performance. The mix-doped LiFe 0.98 Mg 0.01 Ti 0.01 PO 4 material shows the best electrochemical performance due to its smaller crystalline particles and lower the polarization. At the discharge rate of 0.1C, the initial specific capacity of LiFe 0.98 Mg 0.01 Ti 0.01 PO 4 is 105.78 mAh·g -1 , its high-rate performance is also better.