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Moisture-Driven Degradation Pathways in Prussian White Cathode Material for Sodium-Ion Batteries

Ojwang, Dickson O.; Svensson, Mikael; Njel, Christian; Mogensen, Ronnie; Menon, Ashok S.; Ericsson, Tore; Häggström, Lennart; Maibach, Julia; Brant, William R.

Abstract:
The high-theoretical-capacity (∼170 mAh/g) Prussian white (PW), Na$_{x}$Fe[Fe(CN)$_{6}$]$_{y}$·nH$_{2}$O, is one of the most promising candidates for Na-ion batteries on the cusp of commercialization. However, it has limitations such as high variability of reported stable practical capacity and cycling stability. A key factor that has been identified to affect the performance of PW is water content in the structure. However, the impact of airborne moisture exposure on the electrochemical performance of PW and the chemical mechanisms leading to performance decay have not yet been explored. Herein, we for the first time systematically studied the influence of humidity on the structural and electrochemical properties of monoclinic hydrated (M-PW) and rhombohedral dehydrated (R-PW) Prussian white. It is identified that moisture-driven capacity fading proceeds via two steps, first by sodium from the bulk material reacting with moisture at the surface to form sodium hydroxide and partial oxidation of Fe$^{2+}$ to Fe$^{3+}$. The sodium hydroxide creates a basic environment at the surface of the PW particles, leading to decomposition to Na$_{4}$[Fe(CN)$_{6}$] and iron oxides. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000130926
Veröffentlicht am 25.03.2021
Originalveröffentlichung
DOI: 10.1021/acsami.0c22032
Scopus
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Karlsruhe Nano Micro Facility (KNMF)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1944-8244, 1944-8252
KITopen-ID: 1000130926
Erschienen in ACS Applied Materials and Interfaces
Verlag American Chemical Society (ACS)
Band 13
Heft 8
Seiten 10054-10063
Nachgewiesen in Scopus
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