Coulombic self-ordering upon charging a large-capacity layered cathode material for rechargeable batteries

Benoit Mortemard de Boisse (1) , Marine Reynaud (2) , Jiangtao Ma (1) , Jun Kikkawa (3) , Shin-Ichi Nishimura (1, 4) , Montse Casas-Cabanas (2) , Claude Delmas (5) , Masashi Okubo (1, 4) , Atsuo Yamada (1, 4)

1 Department of Chemical System Engineering
2 CIC EnergiGUNE (SPAIN)
3 Advanced Key Technologies Division
4 Unit of Element Strategy Initiative for Catalysts & Batteries, ESICB, Kyoto University
5 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Lithium- and sodium-rich layered transition-metal oxides have recently been attracting significant interest because of their large capacity achieved by additional oxygen-redox reactions. However, layered transition-metal oxides exhibit structural degradation such as cation migration, layer exfoliation or cracks upon deep charge, which is a major obstacle to achieve higher energy-density batteries. Here we demonstrate a self-repairing phenomenon of stacking faults upon desodiation from an oxygen-redox layered oxide Na2RuO3, realizing much better reversibility of the electrode reaction. The phase transformations upon charging A2MO3 (A: alkali metal) can be dominated by three-dimensional Coulombic attractive interactions driven by the existence of ordered alkali-metal vacancies, leading to counterintuitive self-repairing of stacking faults and progressive ordering upon charging. The cooperatively ordered vacancy in lithium-/sodium-rich layered transition-metal oxides is shown to play an essential role, not only in generating the electro-active nonbonding 2p orbital of neighbouring oxygen but also in stabilizing the phase transformation for highly reversible oxygen-redox reactions.

Domaines: Matériaux

Benoit Mortemard de Boisse, Marine Reynaud, Jiangtao Ma, Jun Kikkawa, Shin-Ichi Nishimura, et al.. Coulombic self-ordering upon charging a large-capacity layered cathode material for rechargeable batteries. Nature Communications, 2019, 10, 2185 (7 p.). ⟨10.1038/s41467-019-09409-1⟩. ⟨hal-02135401⟩