LiFePO4 (LFP) is a commercially used Li ion battery material for high power applications. Particle shape and surface play an important role in the Li diffusion and thus the electrochemical performance of the material. After the successful experiment addressing the particle shape and size, we now propose to measure the surface phonon density of states of LFP as a function of surface coatings. Therefore, we kindly request five days of beam time at MARI. This will give us further insights on how surface phonon modes play a role in the size-dependent behavior of the lithium ion diffusion in LFP.