Accurate Electronic Properties and Intercalation Voltages of Olivine-Type Li-Ion Cathode Materials from Extended Hubbard Functionals

The design of novel cathode materials for Li-ion batteries would greatly benefit from accurate first-principles predictions of structural, electronic, and magnetic properties as well as intercalation voltages in compounds containing transition-metal elements. For such systems, density-functional theory (DFT) with standard (semi) local exchange-correlation functionals is of limited use as it often fails due to strong self-interaction errors that are especially relevant in the partially filled d shells. Here, we perform a detailed comparative study of the phospho-olivine cathode materials Li x MnPO 4, Li x FePO 4 and the mixed transition metal Li x Mn 1/2 Fe 1/2 PO 4 (x= 0, 1/4, 1/2, 3/4, 1) using four electronic-structure methods: DFT, DFT+ U, DFT+ U+ V, and HSE06. We show that DFT+ U+ V, with onsite U and intersite V Hubbard parameters determined from first principles and self-consistently with respect to the structura