[sup 7]Li and [sup 1]H MAS NMR Observation of Interphase Layers on Lithium Nickel Oxide Based Positive Electrodes of Lithium-Ion Batteries

and magic-angle spinning (MAS) NMR spectra were recorded for samples. The MAS NMR signal of the layer on the pristine material is close to that of in close contact with it. Its lineshape, due to dipolar interaction with electron spins of the material, is drastically different from that of pure Upon hydration, this layer grows, while NMR suggests that some lithium in the material is replaced by protons. Upon electrochemical cycling, the original layer is replaced by a different one, the solid electrolyte interphase, with distinct and NMR signatures, showing its largely organic nature.