Versatile Approach Combining Theoretical and Experimental Aspects of Raman Spectroscopy To Investigate Battery Materials: The Case of the LiNi0.5Mn1.5O4 Spinel

We report a correlation between experimental and theoretical Raman spectra. Using density functional theory calculations, we resolve the last bottleneck in the understanding of Raman spectra by simulating and coupling the Raman vibrational modes to their calculated intensities of the promising 5-V LiNi0.5Mn1.5O4 spinel cathode. The origin of the simulated Raman intensities is elucidated thanks to a careful analysis of the electronic structure performed on the vibrating atoms in a solid compound. This novel approach leads to correctly assigning the main vibrational modes to Li–O bond motions that are indirectly linked to Mn or Ni (or both), contrary to what has been reported in the literature so far. This methodology will lead to a better understanding of the reaction mechanisms of active materials used for energy applications.