X-Ray Spectroscopy of Cobaltites

A multi-edge study: investigating Co oxidation states of pristine LiNixMnyCo1−x−yO2 cathode materials by high energy-resolution X-ray spectrometry

“…Changes in the oxidation state also manifest in the peak ratios of the L 3 edge. 11,49 Fig. 6 shows a comparison of the Co L-edge NEXAFS measurements for the three cathode materials.…”

“…Peak A is associated with the presence of Co 2+ ions, peak B is a mix of both, Co 2+ and Co 3+ , and peak C is associated with Co 3+ . 11,49 Depending on the oxidation state, the ratios between these features change. 11 Table 5 shows the resulting ratios for the three cathode materials and additionally, the position of peak B.…”

“…11,49 Depending on the oxidation state, the ratios between these features change. 11 Table 5 shows the resulting ratios for the three cathode materials and additionally, the position of peak B. For comparison, two different methods were applied to define the ratios.…”

“…In order to determine the oxidation state of TMs utilizing L-edge NEX-AFS measurements with its 2p-3d dipole allowed transition is acknowledged as the state-of-the-art method. 11 However, given the controversy regarding Co oxidation states in pristine NMC cathodes and the potential bias of relying solely on one method, a complementary approach was chosen in order to provide the most reliable results.…”