Novel polyanion conduction in Sc-2(WO4)(3) type negative thermal expansion oxides

作者：Zhou Yongkai; Neiman Arkady; Adams Stefan^*

来源：Physica Status Solidi B-Basic Solid State Physics, 2011, 248(1): 130-135.

DOI：10.1002/pssb.201083969

• scandium tungstate
• polyatomic ion conduction
• negative thermal expansion
• molecular dynamics simulation

The relationship between the polyatomic anion conduction and negative thermal expansion (NTE) in Sc-2(WO4)(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(WO4)(3). Using the same force-field a series of correlated WO42- migrations are observed in extended isothermal-isobaric MD simulations. Tubandt-type electrolysis experiments confirmed that the mobile species in Sc-2(WO4)(3) is anionic. Scandium tungstate is thus the prototype of novel class of ionic conductors, a WO42- anion conductors. The relationship of the ion transport in this unique ion conductors with polyatomic mobile charge carriers to the NTE is discussed.

• 出版日期2011-1