Anharmonicity in LiBH4–LiI induced by anion exchange and temperature

The feasibility of spatially resolved Raman spectroscopy probing diffusion multiples as a high-throughput method to study phase transformations in Li-ion conductors is demonstrated. The method is applied to the pseudobinary LiBH4–LiI system, which shows high Li-ion conductivity in the HT-phase of LiBH4. The vibrational properties measured as a function of composition and temperature corroborate the formation of a solid solution of Li(BH4)1−cIc over nearly the entire phase diagram (0anharmonic effects responsible for the structural phase transformation in this system.