Impact on electronic correlations on the structural stability, magnetism, and voltage of LiCoPO4 battery

• We present a study of the structural stability of the lithium-orthophosphate oxide LiCoPO4 using density-functional theory within the local-density (LDA), generalized gradient and LDA+U approximation. We show that both enhanced localization and anisotropic effects provided within the LDA+U approximation are essential to reproduce the experimentally observed magnetic structure, lattice parameters, and stability of the lithiated and nonlithiated compound. Within this approximation, the intercalation voltage of 4.6 eV as well as the insulator character of the lithiated and nonlithiated compounds are recovered. Moreover, we found that the LDA+U approximation induces a strong transfer of charge from the t(2g)-like to the e(g)-like orbitals of Co as well as a significant shift of the LiPO4 band. Both effects are competing with each other and determine most of the peculiar properties of the LiCoPO4 and CoPO4 compounds.

Keyword

TECHNOLOGY

TEKNIKVETENSKAP

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art (subject category)