The electronic structure and band gap of LiFePO4 and LiMnPO4

Abstract

Materials with the olivine LixMPO4 structure form an important new class of materials for rechargeable Li batteries. There is significant interest in their electronic properties because of the importance of electronic conductivity in batteries for high rate applications. The density of states of LixMPO4 (x = 0, 1 and M = Fe, Mn) has been determined with the ab initio GGA+U method, appropriate for these correlated electron systems. Computed results are compared with the optical gap of LiFePO4, as measured using UV-Vis-NIR diffuse reflectance spectroscopy. The results obtained from experiment (3.8-4.0 eV) and GGA+U computations (3.7 eV) are in very good agreement. However, standard GGA, without the same level of treatment of electron correlation, is shown to make large errors in predicting the electronic structure. It is argued that olivines are likely to be polaronic conductors with extrinsically determined carrier levels and that their electronic conductivity is therefore not simply related to the band gap.

17 pages, 2 figures

References in corpus (5)

• Phase Separation in Li${}_x$FePO${}_4$ Induced by Correlation Effects
• Density Functional Application to Strongly Correlated Electron Systems
• Structural, electronic, and magneto-optical properties of YVO${}_3$
• Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistance manganite: La0.7Ce0.3MnO3 film
• Investigation of the Jahn-Teller Transition in TiF3 using Density Functional Theory

Cited by in corpus (13)

• Configurational electronic entropy and the phase diagram of mixed-valence oxides: the case of Li${}_x$FePO${}_4$
• Tailoring Native Defects in LiFePO4: Insights from First-Principles Calculations
• Hole polaron formation and migration in olivine phosphate materials
• First-principles studies of the effects of impurities on the ionic and electronic conduction in LiFePO${}_4$
• Energetics and cathode voltages of LiMPO${}_4$ olivines (M = Fe, Mn) from extended Hubbard functionals
• Accurate electronic properties and intercalation voltages of olivine-type Li-ion cathode materials from extended Hubbard functionals
• Fast determination of phases in LiFePO4 using low losses in electron energy-loss spectroscopy
• Unconventional Magnetism and Band Gap Formation in LiFePO4: Consequence of Polyanion Induced Non-planarity
• Prediction of Li intercalation voltages in rechargeable battery cathode materials: effects of exchange-correlation functional, van der Waals interactions, and Hubbard $U$
• Benchmarking density functional theory on the prediction of antiferromagnetic transition temperatures
• Compositional phase stability of strongly correlated electron materials within DFT+$U$
• Engineering Diffusivity and Operating Voltage in Lithium Iron Phosphate through Transition Metal Doping
• Finite-size effect of antiferromagnetic transition and electronic structure in LiFePO4