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Highlighting the Reversible Manganese Electroactivity in Na‐Rich Manganese Hexacyanoferrate Material for Li‐ and Na‐Ion Storage

Mullaliu, Angelo; Asenbauer, Jakob; Aquilanti, Giuliana; Passerini, Stefano; Giorgetti, Marco

The electroactivity of sodium‐rich manganese hexacyanoferrate (MnHCF) material constituted of only abundant elements, as insertion host for Li‐ and Na‐ions is herein comprehensively discussed. This material features high specific capacities (>130 mAh g−1) at high potentials when compared to other materials of the same class, i.e., Prussian blue analogs. The reversible electronic and structural modifications occurring during ion release/uptake, which are responsible for such high specific capacity, are revealed herein. The in‐depth electronic and structural analysis carried out combining X‐ray diffraction and X‐ray absorption spectroscopy (XAS), demonstrates that both Fe and Mn sites are involved in the electrochemical process, being the high delivered capacity the result of a reversible evolution in oxidation states of the metallic centers (Fe3+/Fe2+ and Mn2+/Mn3+). Along with the Mn2+/Mn3+ oxidation, the Mn local environment experiences a substantial yet reversible Jahn–Teller effect, being the equatorial Mn‐N distances shrunk by 10% (2.18 Å → 1.96 Å). Na‐rich MnHCF material offers slightly higher performance upon uptake and release of Na‐ions (469 Wh kg−1) than Li‐ions (457 Wh kg−1), being, however, the electronic and structural transformation independent of the adopted medium, as observed by XAS spectroscopy.

Verlagsausgabe §
DOI: 10.5445/IR/1000098731
Veröffentlicht am 10.02.2020
DOI: 10.1002/smtd.201900529
Zitationen: 15
Zitationen: 17
Cover der Publikation
Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2366-9608, 2366-9608
KITopen-ID: 1000098731
HGF-Programm 37.01.01 (POF III, LK 01) Fundamentals and Materials
Erschienen in Small methods
Verlag Wiley-VCH Verlag
Band 4
Heft 1
Seiten Article: 1900529
Vorab online veröffentlicht am 25.09.2019
Nachgewiesen in Web of Science
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