Vibrational Contribution to the Thermodynamic Properties of Lithium Ion Battery Cathode Material, LiFePO4

We propose to measure phonon density of states in LixFePO4 (x = 0.3, 0.6 and 1.0; three sample) from 300 to 1000 K to understand the role of lithium disorder with change in x values. Vibrational entropy or the phonon entropy plays a significant role in the intercalation potential of the electrode materials. We would study the effect of compositional change in LixFePO4 on the phonon entropy, which in turn governs the intercalation potential for the delithiation process. The measurements would throw light on the real chemical changes occurring in the lattice as battery is operated. The measured phonon density of states along with the ab-initio calculations would be used to calculate the vibrational contribution to the thermodynamic quantities, which is directly associated with the intercalation potential of electrode materials for lithium ion batteries.