Abstract Colossal dielectric properties in donor-acceptor co-doped rutile TiO2 ceramics have attracted increased interest in recent years. However, dielectric loss (tan δ) of (Nb+Al) co-doped TiO2 ceramics are quite scattered in the previous studies. Here, we show the dielectric properties of (Nb+Al) co-doped rutile TiO2 ceramics are sensitive to sintering and ageing technologies, which is related to the coupling behavior of acceptor-donor ions. Both permittivity and dielectric loss of as-sintered (Nb+Al) co-doped TiO2 ceramics are very large, and increase with the sintering time increasing. After ageing treatment at 900 °C, the dielectric loss of co-doped ceramics reduces from 139 to 0.15 in a wide frequency range. Based on the X-ray diffraction and complex impedance analyses, it can conclude that Nb5+-Al3+ pair formation during ageing treatment reduces the concentration of oxygen vacancy, resulting in the decreases of the conductivity and dielectric loss. The changes in dielectric response of (Nb+Al) co-doped TiO2 ceramics clearly suggest that ageing process is an effective way for the Nb5+ and Al3+ ions to form the Nb5+-Al3+ pairs. We believe that the coupling effect of donor-acceptor ions is a practical and feasible route to reduce the dielectric loss of (Nb+Al) co-doped TiO2 ceramics for high-energy-density storage applications.

中文翻译：

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(Nb+Al)共掺杂金红石TiO 2 大介电常数陶瓷中供体-受体离子耦合效应引起的低介电损耗

摘要 近年来，供体-受体共掺杂的金红石型 TiO2 陶瓷的巨大介电性能引起了越来越多的关注。然而，(Nb+Al) 共掺杂 TiO2 陶瓷的介电损耗 (tanδ) 在先前的研究中相当分散。在这里，我们展示了 (Nb+Al) 共掺杂金红石型 TiO2 陶瓷的介电性能对烧结和老化技术敏感，这与受体-供体离子的耦合行为有关。烧结态(Nb+Al)共掺杂TiO2陶瓷的介电常数和介电损耗都非常大，并且随着烧结时间的增加而增加。在900℃时效处理后，共掺杂陶瓷的介电损耗在较宽的频率范围内从139降低到0.15。基于 X 射线衍射和复阻抗分析，可以得出结论，时效处理过程中形成的 Nb5+-Al3+ 对降低了氧空位的浓度，导致电导率和介电损耗的降低。(Nb+Al) 共掺杂 TiO2 陶瓷介电响应的变化清楚地表明时效过程是 Nb5+ 和 Al3+ 离子形成 Nb5+-Al3+ 对的有效途径。我们认为，供体-受体离子的耦合效应是降低（Nb+Al）共掺杂 TiO2 陶瓷用于高能量密度存储应用的介电损耗的实用可行的途径。