Configurational electronic entropy and the phase diagram of mixed-valence oxides: the case of Li${}_x$FePO${}_4$

Abstract

We demonstrate that configurational electronic entropy, previously neglected, in {\it ab initio} thermodynamics of materials can qualitatively modify the finite-temperature phase stability of mixed-valence oxides. While transformations from low-T ordered or immiscible states are almost always driven by configurational disorder (i.e. random occupation of lattice sites by multiple species), in FePO${}_4$--LiFePO${}_4$ the formation of a solid solution is almost entirely driven by electronic, rather than ionic configurational entropy. We argue that such an electronic entropic mechanism may be relevant to most other mixed-valence systems.

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References in corpus (4)

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• Phase Separation in Li${}_x$FePO${}_4$ Induced by Correlation Effects

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