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

Mortemard de Boisse B, Liu G, Ma J, Nishimura S, Chung SC, Kiuchi H, Harada Y, Kikkawa J, Kobayashi Y, Okubo M, Yamada A - Nat Commun (2016)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, 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.

No MeSH data available.


Related in: MedlinePlus

Structure of ordered and disordered Na2RuO3.Oxide ions (red) stack in the manner of ABCABC while both Na (yellow) and Ru (grey) occupy octahedral sites for both Na2RuO3. Ordered Na2RuO3 has the honeycomb-type cation ordering in the [Na1/3Ru2/3]O2 slab. Disordered Na2RuO3 has the randomly distributed [Na1/3Ru2/3]O2 slab.
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f1: Structure of ordered and disordered Na2RuO3.Oxide ions (red) stack in the manner of ABCABC while both Na (yellow) and Ru (grey) occupy octahedral sites for both Na2RuO3. Ordered Na2RuO3 has the honeycomb-type cation ordering in the [Na1/3Ru2/3]O2 slab. Disordered Na2RuO3 has the randomly distributed [Na1/3Ru2/3]O2 slab.

Mentions: Here we demonstrate that a highly stabilized intermediate phase with honeycomb-type cation ordering in the [Na1/3M2/3]O2 slab is critical for the effective use of the ‘A2−xMO3' strategy, by comparing two polymorphs of Na2RuO3; namely, ‘ordered' Na2RuO3 with honeycomb-ordered [Na1/3M2/3]O2 slabs and ‘disordered' Na2RuO3 with randomly distributed [Na1/3M2/3]O2 slabs (Fig. 1).


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

Mortemard de Boisse B, Liu G, Ma J, Nishimura S, Chung SC, Kiuchi H, Harada Y, Kikkawa J, Kobayashi Y, Okubo M, Yamada A - Nat Commun (2016)

Structure of ordered and disordered Na2RuO3.Oxide ions (red) stack in the manner of ABCABC while both Na (yellow) and Ru (grey) occupy octahedral sites for both Na2RuO3. Ordered Na2RuO3 has the honeycomb-type cation ordering in the [Na1/3Ru2/3]O2 slab. Disordered Na2RuO3 has the randomly distributed [Na1/3Ru2/3]O2 slab.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837481&req=5

f1: Structure of ordered and disordered Na2RuO3.Oxide ions (red) stack in the manner of ABCABC while both Na (yellow) and Ru (grey) occupy octahedral sites for both Na2RuO3. Ordered Na2RuO3 has the honeycomb-type cation ordering in the [Na1/3Ru2/3]O2 slab. Disordered Na2RuO3 has the randomly distributed [Na1/3Ru2/3]O2 slab.
Mentions: Here we demonstrate that a highly stabilized intermediate phase with honeycomb-type cation ordering in the [Na1/3M2/3]O2 slab is critical for the effective use of the ‘A2−xMO3' strategy, by comparing two polymorphs of Na2RuO3; namely, ‘ordered' Na2RuO3 with honeycomb-ordered [Na1/3M2/3]O2 slabs and ‘disordered' Na2RuO3 with randomly distributed [Na1/3M2/3]O2 slabs (Fig. 1).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, 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.

No MeSH data available.


Related in: MedlinePlus