Intercalation and Push‐Out Process with Spinel‐to‐Rocksalt Transition on Mg Insertion into Spinel Oxides in Magnesium Batteries. Issue 8 (10th June 2015)

• Record Type: Journal Article
• Authors: Okamoto, Shinya; Ichitsubo, Tetsu; Kawaguchi, Tomoya; Kumagai, Yu; Oba, Fumiyasu; Yagi, Shunsuke; Shimokawa, Kohei; Goto, Natsumi; Doi, Takayuki; Matsubara, Eiichiro
• Is Part Of: Advanced science. Volume 2:Issue 8(2015:Aug.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2015-06-10
• Subjects: Science -- Periodicals; 505
• DOI: 10.1002/advs.201500072
• Languages: English
• ISSNs: 2198-3844

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>On the basis of the similarity between spinel and rocksalt structures, it is shown that some spinel oxides (e.g., MgCo<sub>2</sub>O<sub>4</sub>, etc) can be cathode materials for Mg rechargeable batteries around 150 °C. The Mg insertion into spinel lattices occurs via "intercalation and push‐out" process to form a rocksalt phase in the spinel mother phase. For example, by utilizing the valence change from Co(III) to Co(II) in MgCo<sub>2</sub>O<sub>4</sub>, Mg insertion occurs at a considerably high potential of about 2.9 V vs. Mg<sup>2+</sup>/Mg, and similarly it occurs around 2.3 V vs. Mg<sup>2+</sup>/Mg with the valence change from Mn(III) to Mn(II) in MgMn<sub>2</sub>O<sub>4</sub>, being comparable to the ab initio calculation. The feasibility of Mg insertion would depend on the phase stability of the counterpart rocksalt XO of MgO in Mg<sub>2</sub>X<sub>2</sub>O<sub>4</sub> or MgX<sub>3</sub>O<sub>4</sub> (X = Co, Fe, Mn, and Cr). In addition, the normal spinel MgMn<sub>2</sub>O<sub>4</sub> and MgCr<sub>2</sub>O<sub>4</sub> can be demagnesiated to some extent owing to the robust host structure of Mg<sub>1−x</sub>X<sub>2</sub>O<sub>4</sub>, where the Mg extraction/insertion potentials for MgMn<sub>2</sub>O<sub>4</sub> and MgCr<sub>2</sub>O<sub>4</sub> are both about 3.4 V vs. Mg<sup>2+</sup>/Mg. Especially, the former "intercalation and push‐out" process would provide a safe and stable design of cathode materials for polyvalent cations.</p> </abstract>