Epitaxial Nickel Ferrocyanide Stabilizes Jahn-Teller Distortions of Manganese Ferrocyanide for Sodium-Ion Batteries.
Angew Chem Int Ed Engl
; 60(34): 18519-18526, 2021 Aug 16.
Article
en En
| MEDLINE
| ID: mdl-34096153
ABSTRACT
Manganese-based Prussian Blue, Na2-δ Mn[Fe(CN)6 ] (MnPB), is a good candidate for sodium-ion battery cathode materials due to its high capacity. However, it suffers from severe capacity decay during battery cycling due to the destabilizing Jahn-Teller distortions it undergoes as Mn2+ is oxidized to Mn3+ . Herein, the structure is stabilized by a thin epitaxial surface layer of nickel-based Prussian Blue (Na2-δ Ni[Fe(CN)6 ]). The one-pot synthesis relies on a chelating agent with an unequal affinity for Mn2+ and Ni2+ ions, which prevents Ni2+ from reacting until the Mn2+ is consumed. This is a new and simpler synthesis of core-shell materials, which usually needs several steps. The material has an electrochemical capacity of 93â
mA h g-1 , of which it retains 96 % after 500 charge-discharge cycles (vs. 37 % for MnPB). Its rate capability is also remarkable at 4â
A g-1 (ca. 55â
C) it can reversibly store 70â
mA h g-1 , which is also reflected in its diffusion coefficient of ca. 10-8 â
cm2 s-1 . The epitaxial outer layer appears to exert an anisotropic strain on the inner layer, preventing the Jahn-Teller distortions it normally undergoes during de-sodiation.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2021
Tipo del documento:
Article
País de afiliación:
Australia