Raman and NMR studies of aged LiFePO4 cathode

► Raman spectroscopy used to characterize the quality of carbon coating in LiFePO4 commercial cells aged with C-rate. ► Structural change in the carbon coating leading to low electrical conductivity is observed for the cells aged at higher C-rate. ► Nuclear magnetic spectroscopy used to characterize LiFePO4 nanoparticles for the presence of Li. ► 7Li peak is observed in an unaged cell, while the similar peak is absent in the aged cells.