Intermediate honeycomb ordering to trigger oxygen redox chemistry in layered battery electrode

Benoit Mortemard de Boisse; Guandong Liu; Jiangtao Ma; Shin-Ichi Nishimura; Sai-Cheong Chung; Hisao Kiuchi; Yoshihisa Harada; Jun Kikkawa; Yoshio Kobayashi; Masashi Okubo; Atsuo Yamada

doi:10.1038/ncomms11397

Intermediate honeycomb ordering to trigger oxygen redox chemistry in layered battery electrode

Nat Commun. 2016 Apr 18:7:11397. doi: 10.1038/ncomms11397.

Authors

Benoit Mortemard de Boisse^{1

2}, Guandong Liu¹, Jiangtao Ma¹, Shin-Ichi Nishimura^{1

2}, Sai-Cheong Chung^{1

2}, Hisao Kiuchi³, Yoshihisa Harada^{4

5}, Jun Kikkawa⁶, Yoshio Kobayashi^{7

8}, Masashi Okubo^{1

2}, Atsuo Yamada^{1

2}

Affiliations

¹ Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan.
² Elements Strategy Initiative for Catalysts &Batteries (ESICB), Kyoto University, Nishikyo-ku, Kyoto 615-8245, Japan.
³ Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
⁴ Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
⁵ Synchrotron Radiation Research Organization, The University of Tokyo, Tatsuno, Hyogo 679-5165, Japan.
⁶ Advanced Key Technologies Division, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
⁷ Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.
⁸ RIKEN Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitame 351-0198, Japan.

Abstract

Sodium-ion batteries are attractive energy storage media owing to the abundance of sodium, but the low capacities of available cathode materials make them impractical. Sodium-excess metal oxides Na2MO3 (M: transition metal) are appealing cathode materials that may realize large capacities through additional oxygen redox reaction. However, the general strategies for enhancing the capacity of Na2MO3 are poorly established. Here using two polymorphs of Na2RuO3, we demonstrate the critical role of honeycomb-type cation ordering in Na2MO3. Ordered Na2RuO3 with honeycomb-ordered [Na(1/3)Ru(2/3)]O2 slabs delivers a capacity of 180 mAh g(-1) (1.3-electron reaction), whereas disordered Na2RuO3 only delivers 135 mAh g(-1) (1.0-electron reaction). We clarify that the large extra capacity of ordered Na2RuO3 is enabled by a spontaneously ordered intermediate Na1RuO3 phase with ilmenite O1 structure, which induces frontier orbital reorganization to trigger the oxygen redox reaction, unveiling a general requisite for the stable oxygen redox reaction in high-capacity Na2MO3 cathodes.

Publication types

Research Support, Non-U.S. Gov't