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Novel polyanion conduction in Sc 2 (WO 4 ) 3 type negative thermal expansion oxides
Author(s) -
Zhou Yongkai,
Neiman Arkady,
Adams Stefan
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201083969
Subject(s) - negative thermal expansion , polyatomic ion , tungstate , ion , ionic bonding , ionic conductivity , thermal conduction , chemistry , tungsten , isothermal process , materials science , chemical physics , thermal expansion , inorganic chemistry , thermodynamics , electrolyte , electrode , physics , composite material , metallurgy , organic chemistry
The relationship between the polyatomic anion conduction and negative thermal expansion (NTE) in Sc 2 (WO 4 ) 3 type structure has been investigated by a combination of computational, electrochemical and X‐ray diffraction approaches. The motion of the effective charge carriers in solid‐state ionics can be visualised by molecular dynamics (MD) simulations if proper initial structure and force‐field are known. By successfully reproducing the NTE for a large temperature range, we have designed and verified a valid force‐field to predict the mobile species in Sc 2 (WO 4 ) 3 . Using the same force‐field a series of correlated WO 4 2−migrations are observed in extended isothermal–isobaric MD simulations. Tubandt‐type electrolysis experiments confirmed that the mobile species in Sc 2 (WO 4 ) 3 is anionic. Scandium tungstate is thus the prototype of novel class of ionic conductors, a WO 4 2−anion conductors. The relationship of the ion transport in this unique ion conductors with polyatomic mobile charge carriers to the NTE is discussed.