Compositional Dependence of the Proton Conductivity of Anodic ZrO2-WO3-SiO2 Nanofilms at Intermediate Temperatures
Compositional Dependence of the Proton Conductivity of Anodic ZrO2-WO3-SiO2 Nanofilms at Intermediate Temperatures
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DOI：
10.1149/2.120309jes
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发表时间：
2013
影响因子：
3.9
通讯作者：
K. Ye;Y. Aoki;E. Tsuji;S. Nagata;H. Habazaki
中科院分区：
文献类型：
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作者：
K. Ye;Y. Aoki;E. Tsuji;S. Nagata;H. Habazaki
通过磁控溅射Zr-W-Si合金在0.1 mol dm - 3磷酸电解液中在20◦C下阳极氧化，制备了各种成分和厚度（~ 50 ~ ~ 300nm）的新质子导电zro2 - wo3 - sio2纳米膜。所有的阳极氧化纳米膜在250◦C退火后显示出有效的质子导电性，退火后温度的进一步增加导致仅含5% at%硅的合金的阳极氧化纳米膜的导电性下降，而那些含15% at%或更多硅的合金的阳极氧化纳米膜即使在300◦C退火后仍保持高导电性。质子电导率取决于钨的含量；Zr31W55Si14上的~ 100 nm厚薄膜在100◦C时的电导率为5 × 10−6 Sc m−1，约为Zr48W37Si15的10倍。阳极氧化纳米膜由两层组成，包括薄的外ZrO2层和内ZrO2- wo3 - sio2层。两层都显示出与厚度相关的电导率，并且通过将膜厚度从~ 300 nm减小到~ 100 nm，两层阳极膜的质子电导率提高了一个数量级。提出了不同的机制，厚度依赖于电导率的外层和内层。
Novelproton-conductingZrO2-WO3-SiO2 nanofilmsofvariouscompositionsandthicknesses(∼50to ∼300nm)havebeenprepared by anodizing of magnetron-sputtered Zr-W-Si alloys in 0.1 mol dm−3 phosphoric acid electrolyte at 20◦C. All the anodic oxide nanofilms examined reveal efficient proton conductivity after post-annealing at 250 ◦ C. Further increase in the post-annealing temperature results in the conductivity degradation for the anodic oxide nanofilms on the alloy containing only 5 at% silicon, while the high conductivity is maintained even after post-annealing at 300 ◦ C for those containing 15 at% or more silicon. The proton conductivity is dependent upon tungsten content; the conductivity of 5 × 10 −6 Sc m −1 for the ∼100 nm-thick films on the Zr31W55Si14 at 100 ◦ C is approximately 10 times that on the Zr48W37Si15. The anodic oxide nanofilms consist of two layers, comprising a thin outer ZrO2 layer and an inner ZrO2-WO3-SiO2 layer. Both layers show thickness-dependent conductivity and the proton conductivity of the two-layer anodic films is enhanced one order of magnitude by reducing the film thickness from ∼300 nm to ∼100 nm. Different mechanisms are proposed for the thickness dependence of the conductivity of the outer and inner layers.