| Abstract
| - In situ hard X-ray absorption spectroscopy (XAS) at metal K-edges and soft XAS at O K-edgeand metal L-edges have been carried out during the first charging process for the layered Li1-xCo1/3Ni1/3Mn1/3O2cathode material. The metal K-edge XANES results show that the major charge compensation at the metalsite during Li-ion deintercalation is achieved by the oxidation of Ni2+ ions, while the manganese ions andthe cobalt ions remain mostly unchanged in the Mn4+ and Co3+ state. These conclusions are in goodagreement with the results of the metal K-edge EXAFS data. Metal L-edge XAS results at different chargestates in both the FY and PEY modes show that, unlike Mn and Co ions, Ni ions at the surface are oxidizedto Ni3+ during charge, whereas Ni ions in the bulk are further oxidized to Ni4+ during charge. From theobservation of O K-edge XAS results, we can conclude that a large portion of the charge compensationduring Li-ion deintercalation is achieved in the oxygen site. By comparison to our earlier results on theLi1-xNi0.5Mn0.5O2 system, we attribute the active participation of oxygen in the redox process inLi1-xCo1/3Ni1/3Mn1/3O2 to be related to the presence of Co in this system.
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