We discuss how x-ray Compton scattering spectra can be used for investigating the evolution of electronic states in cathode materials of Li batteries under the lithiation/delithiation process. In particular, our analysis of the Compton spectra taken from polycrystalline LixCoO2 samples shows that the spectra are dominated by the contribution of the O-2p redox orbital. We identify a distinct signature of d-orbital delocalization, which is tied directly to the conductivity of the material, providing a descriptor based on Compton spectra for monitoring the lithiation range with improved conductivity and kinetics for electrochemical operation. Our study demonstrates that Compton scattering spectroscopy can provide a window for probing complex electronic mechanisms underlying the charging and discharging processes in Li-battery materials.
@article{arxiv.1608.02391,
title = {Identifying a descriptor for d-orbital delocalization in cathodes of Li batteries based on x-ray Compton scattering},
author = {B. Barbiellini and K. Suzuki and Y. Orikasa and S. Kaprzyk and M. Itou and K. Yamamoto and Yung Jui Wang and H. Hafiz and R. Yamada and Y. Uchimoto and A. Bansil and Y. Sakurai and H. Sakurai},
journal= {arXiv preprint arXiv:1608.02391},
year = {2016}
}