High Energy Density, High Temperature Capacitors Utilizing Mn-Doped 0.8CaTiO3–0.2CaHfO3 Ceramics
High Energy Density, High Temperature Capacitors Utilizing Mn-Doped 0.8CaTiO3–0.2CaHfO3 Ceramics
复制标题
DOI：
10.1111/j.1551-2916.2011.04962.x
复制
发表时间：
2012-04
影响因子：
3.9
通讯作者：
Dennis P. Shay;N. Podraza;N. J. Donnelly;C. Randall
中科院分区：
文献类型：
--
作者：
Dennis P. Shay;N. Podraza;N. J. Donnelly;C. Randall
采用 Pt 内电极的单层空气共烧电容器原型为 0.8CaTiO3–0.2CaHfO3 (CHT) 和 0.5 mol% Mn 掺杂 0.8CaTiO3–0.2CaHfO3 (CHT + Mn)，产生室温相对介电常数为 er ~170、电容热系数 (TCC) 为 -50°C 至 150°C 范围内为 ±15.8% 至 ±16.4%，带隙约为 4.0 eV。阻抗谱表明，Mn 掺杂降低了离子和电子电导率。未掺杂的 CHT 单层电容器的环境能量密度高达 9.0 J/cm3，但在 100°C 以上能量密度急剧下降。当掺杂 0.5 mol% Mn 时，击穿强度的温度依赖性降至最低，并且在高达 200°C 的温度下观察到与环境值 (9.5 J/cm3) 相似的能量密度。在 300°C 时，测得能量密度高达 6.5 J/cm3。这些电介质的设计原理集中在具有大带隙、线性或弱非线性介电常数以及高击穿强度的材料上。这些观察结果表明，随着晶粒尺寸和介电层厚度的进一步减小，CaTiO3-CaHfO3 系统成为集成到未来电力电子应用中的有力候选者。
Single layer air co-fired capacitors with Pt internal electrodes were prototyped for the compositions 0.8CaTiO3–0.2CaHfO3 (CHT) and 0.5 mol% Mn-doped 0.8CaTiO3–0.2CaHfO3 (CHT + Mn) to yield a material with a room-temperature relative permittivity of er ~170, thermal coefficient of capacitance (TCC) of ±15.8% to ±16.4% from −50°C to 150°C, and a band gap of ~4.0 eV. Impedance spectroscopy revealed that doping with Mn reduces both the ionic and electronic conductivity. Undoped CHT single layer capacitors exhibited ambient energy densities as large as 9.0 J/cm3, but showed a drastic decrease in energy density above 100°C. When doped with 0.5 mol% Mn, the temperature dependence of the breakdown strength was minimized, and energy densities similar to ambient values (9.5 J/cm3) were observed up to 200°C. At 300°C, energy densities as large as 6.5 J/cm3 were measured. The design rationale for these dielectrics centered on materials with large band gaps, linear or weakly nonlinear permittivities, and high breakdown strengths. These observations suggest that with further reductions in grain size and dielectric layer thickness, the CaTiO3–CaHfO3 system is a strong candidate for integration into future power electronics applications.