@article{bb907dbe7770442ebfc20bc22dbbdced,
title = "Oxygen redox in hexagonal layered Na: XTMO3 (TM = 4d elements) for high capacity Na ion batteries",
abstract = "Through comprehensive density functional calculations, we demonstrate oxygen's significant participation in the redox reaction in a Na excess NaxRuO3 cathode material. The availability of O electrons for the redox reaction originates from the local coordination environment. For high sodium content (x ≈ 2), O ions in the layered hexagonal Na2RuO3 compound are coordinated by four Na ions and consequently have their 2p electrons lifted closer to the Fermi level. For lower Na content (x ≈ 1), Na1RuO3 adopts an ilmenite type R3 structure in which O ions are coordinated by two Ru and two Na ions. In this case, O under-coordination further elevates O 2p states closer to the Fermi level. In both cases, high O electronic population near the Fermi level facilitates continuous participation of O in the redox reaction over a wide range of Na concentrations. Based on this concept, we also predict that Na1NbO3 with an ilmenite framework is a suitable and economical candidate for high voltage and high capacity cathodes for Na ion batteries.",
author = "Assadi, {M. H.N.} and Masashi Okubo and Atsuo Yamada and Yoshitaka Tateyama",
note = "Funding Information: This work was nancially supported in part by JSPS and MEXT KAKENHI, Grant Numbers JP15K05138, JP15K13798 and JP15H05701. This work was also supported by MEXT, Japan, under the “Elements Strategy Initiative for Catalysts and Batteries (ESICB)”. The calculations were carried out on the supercomputers in NIMS, Institute for Solid State Physics, and The University of Tokyo and the supercomputers in Kyushu University. This research also used computational resources of the HPCI system through the HPCI System Research Projects (Project IDs: hp170122, hp170169). Funding Information: This work was financially supported in part by JSPS and MEXT KAKENHI, Grant Numbers JP15K05138, JP15K13798 and JP15H05701. This work was also supported by MEXT, Japan, under the {"}Elements Strategy Initiative for Catalysts and Batteries (ESICB){"}. The calculations were carried out on the supercomputers in NIMS, Institute for Solid State Physics, and The University of Tokyo and the supercomputers in Kyushu University. This research also used computational resources of the HPCI system through the HPCI System Research Projects (Project IDs: hp170122, hp170169). Publisher Copyright: {\textcopyright} The Royal Society of Chemistry 2018.",
year = "2018",
doi = "10.1039/c7ta10826e",
language = "English",
volume = "6",
pages = "3747--3753",
journal = "Journal of Materials Chemistry A",
issn = "2050-7488",
publisher = "Royal Society of Chemistry",
number = "8",
}