Degree of covalency of LiCoO2: X-ray emission and photoelectron study

The layered compound LiCoO2 was studied by means of X-ray emission (CoLα, OKα spectra) and X-ray photoelectron spectroscopy. The data were compared with those of CoO. Strong covalency of LiCoO2 was found and its value was estimated. The measurements show that LiCoO2 must be determined as a charge-transfer insulator where the band gap is formed by d6L-states.