Origin of chemical shift of manganese in lithium battery electrode materials—a comparison of hard and soft X-ray techniques

L-edge X-ray absorption near edge spectroscopy and K_β emission spectroscopy were applied to monitor ex situ chemical valence changes of manganese in battery electrode materials as they appear during electrode processing and battery operation. We found that significant chemical shifts of the spectra occur already during electrode fabrication, prior to any electrochemical treatment. Employment of these two different techniques allows for the qualitative separation of contributions originating from the surface and from the bulk of the electrode particles.