title: Rechargeable magnesium-ion battery based on a TiSe2-cathode with d-p orbital hybridized electronic structure.
abstract: Rechargeable ion-batteries, in which ions such as Li(+) carry charges between electrodes, have been contributing to the improvement of power-source performance in a wide variety of mobile electronic devices. Among them, Mg-ion batteries are recently attracting attention due to possible low cost and safety, which are realized by abundant natural resources and stability of Mg in the atmosphere. However, only a few materials have been known to work as rechargeable cathodes for Mg-ion batteries, owing to strong electrostatic interaction between Mg(2+) and the host lattice. Here we demonstrate rechargeable performance of Mg-ion batteries at ambient temperature by selecting TiSe2 as a model cathode by focusing on electronic structure. Charge delocalization of electrons in a metal-ligand unit through d-p orbital hybridization is suggested as a possible key factor to realize reversible intercalation of Mg(2+) into TiSe2. The viewpoint from the electronic structure proposed in this study might pave a new way to design electrode materials for multivalent-ion batteries.
authors.affiliation: Department of Advanced Materials Science. The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Japan.
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Applied Physics. The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-8656, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Katsura
authors.affiliation: Department of Advanced Materials Science. The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yoshino
authors.affiliation: 1] Department of Advanced Materials Science. The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Japan [2] Department of Physics. The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan [3] Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart, D-70569, Germany.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Takagi
authors.affiliation: 1] Institute for Materials Research. Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan [2] Elements Strategy Initiative for Catalysts and Batteries (ESICB). Kyoto University, Katsura, Kyoto, 615-8520, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Taniguchi