Improved oxide-ion conductivity by substitution of Sr for Bi in Dion-Jacobson phase CsBi2Ti2NbO10
Improved oxide-ion conductivity by substitution of Sr for Bi in Dion-Jacobson phase CsBi2Ti2NbO10
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DOI：
10.1016/j.ceramint.2022.02.059
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发表时间：
2022-02
影响因子：
5.2
通讯作者：
Wenrui Zhang;M. Yashima
中科院分区：
文献类型：
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作者：
Wenrui Zhang;M. Yashima
氧化物离子导电陶瓷因其在固体氧化物电解电池(SOECs)、固体氧化物燃料电池(SOFCs)等领域的广泛应用而备受关注。本文首次报道了氧-离子导电Dion-Jacobson相CsBi1.9M0.1Ti2NbO9.95(M=0.1Mg，Ca，Sr和Ba)的制备、电学和结构性质。研究发现，Sr2+部分取代Bi3+提高了CsBi2Ti2NbO10的电导率。在600-900℃，CsBi1.9Sr0.1Ti2NbO9.95的电导率约为CsBi2Ti2NbO10的2倍，900℃时，CsBi1.9Sr0.1Ti2NbO9.95的电导率为1.65T×10−2S/cm−1。CsBi1.9Sr0.1Ti2NbO9.95的氧离子电导率的提高可以归因于载流子(氧空位)浓度的增加和掺杂锶与基质铋离子之间的小尺寸失配。在600℃下，CsBi1.9Sr0.1Ti2NbO9.95的电导率在10−~1atm的氧分压范围内几乎保持不变，表明CsBi1.9Sr0.1Ti2NbO9.95以氧离子导电为主，具有较高的化学和电学稳定性。CsBi1.9Sr0.1Ti2NbO9.95中一个测试氧离子的键价能谱表明，氧离子沿钙钛矿层内八面体的边缘迁移，导致了二维氧离子扩散。本研究成功地证明了通过在Dion-Jacobson相中的取代来改善氧化物离子的导电性，这将对Dion-Jacobson型氧化物离子导体的科学和技术的发展起到推动作用。
Oxide ion conducting ceramics have attracted much attention due to their various applications such as solid oxide electrolysis cells (SOECs) and solid-oxide fuel cells (SOFCs). Herein, we present the first report on the preparation, electrical and structural properties of oxide-ion conducting Dion-Jacobson phases CsBi1.9M0.1Ti2NbO9.95(M= Mg, Ca, Sr and Ba). It was found that partial substitution of Bi3+by Sr2+improves the conductivity of CsBi2Ti2NbO10. The electrical conductivity of CsBi1.9Sr0.1Ti2NbO9.95is approximately 2 times higher than that of CsBi2Ti2NbO10at 600–900 °C and is 1.65 × 10−2S cm−1at 900 °C. The improvement of oxide-ion conductivity in CsBi1.9Sr0.1Ti2NbO9.95can be attributed to the increase of the carrier (oxygen vacancy) concentration and small size mismatch between the dopant Sr and host Bi cations. The electrical conductivities of CsBi1.9Sr0.1Ti2NbO9.95are almost constant in the oxygen partial pressure region from 10−25to 1 atm at 600 °C, indicating the predominant oxide-ion conduction and high chemical and electrical stability. Bond-valence-based energy landscapes of a test oxide ion in CsBi1.9Sr0.1Ti2NbO9.95suggest that oxide ions migrate along the edges of the octahedra in the inner perovskite layers, leading to two-dimensional oxide-ion diffusion. This study demonstrates the successful improvement of oxide-ion conductivity by the substitution in Dion-Jacobson phase, which would develop the science and technology of Dion-Jacobson type oxide-ion conductors.