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Epitaxial Nickel Ferrocyanide Stabilizes Jahn���Teller Distortions of Manganese Ferrocyanide for Sodium-Ion Batteries

Journal Article


Abstract


  • Manganese-based Prussian Blue, Na2�����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�����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 93 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 4 A g���1 (ca. 55 C) it can reversibly store 70 mA h g���1, which is also reflected in its diffusion coefficient of ca. 10���8 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.

Publication Date


  • 2021

Citation


  • Gebert, F., Cortie, D. L., Bouwer, J. C., Wang, W., Yan, Z., Dou, S. X., & Chou, S. L. (2021). Epitaxial Nickel Ferrocyanide Stabilizes Jahn���Teller Distortions of Manganese Ferrocyanide for Sodium-Ion Batteries. Angewandte Chemie - International Edition, 60(34), 18519-18526. doi:10.1002/anie.202106240

Scopus Eid


  • 2-s2.0-85109972374

Start Page


  • 18519

End Page


  • 18526

Volume


  • 60

Issue


  • 34

Place Of Publication


Abstract


  • Manganese-based Prussian Blue, Na2�����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�����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 93 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 4 A g���1 (ca. 55 C) it can reversibly store 70 mA h g���1, which is also reflected in its diffusion coefficient of ca. 10���8 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.

Publication Date


  • 2021

Citation


  • Gebert, F., Cortie, D. L., Bouwer, J. C., Wang, W., Yan, Z., Dou, S. X., & Chou, S. L. (2021). Epitaxial Nickel Ferrocyanide Stabilizes Jahn���Teller Distortions of Manganese Ferrocyanide for Sodium-Ion Batteries. Angewandte Chemie - International Edition, 60(34), 18519-18526. doi:10.1002/anie.202106240

Scopus Eid


  • 2-s2.0-85109972374

Start Page


  • 18519

End Page


  • 18526

Volume


  • 60

Issue


  • 34

Place Of Publication