Kinetic Monte Carlo simulations of oxygen vacancy diffusion in a solid electrolyte: Computing the electrical impedance using the fluctuation–dissipation theorem
Kinetic Monte Carlo simulations of oxygen vacancy diffusion in a solid electrolyte: Computing the electrical impedance using the fluctuation–dissipation theorem
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固体电解质中氧空位扩散的动力学蒙特卡罗模拟：使用波动耗散定理计算电阻抗
DOI：
10.1016/j.elecom.2009.11.031
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发表时间：
2010
影响因子：
5.4
通讯作者：
W. Cai
中科院分区：
文献类型：
--
作者：
Eunseok Lee;F. Prinz;W. Cai
我们提出了一种通过氧空位扩散的动力学蒙特卡罗模拟计算固体氧化物电解质电阻抗的新方法。所有频率下的阻抗值都是根据波动耗散定理从单一平衡模拟中获得的，与现有方法相比，效率显着提高。这使我们能够系统地检查掺杂剂浓度的影响。发现增加掺杂剂浓度会降低无限频率阻抗，这是由于氧空位密度的增加。另一方面，零频率和无限频率下的阻抗值之间的差异显示出相反的趋势，并且与掺杂剂-空位相互作用有关。因此，先前提出的用于解释最佳掺杂浓度存在的两种竞争机制是分别量化的。我们的模型还预测了掺杂剂阳离子的排列对电解质电导率的显着影响。
We present a new method for computing the electrical impedance of solid oxide electrolyte from kinetic Monte Carlo simulations of oxygen vacancy diffusion. The impedance values at all frequencies are obtained from a single equilibrium simulation based on the fluctuation–dissipation theorem, leading to a significant gain of efficiency over existing methods.This allows us to systematically examine the effect of dopant concentration. Increasing dopant concentration is found to decrease the infinite-frequency impedance, which is attributed to the increasing density of oxygen vacancies. The difference between the impedance values at zero- and infinite-frequency, on the other hand, shows the opposite trend, and is linked to dopant–vacancy interactions. Hence the two competing mechanisms, previously proposed to explain the existence of an optimal doping concentration, are separately quantified.Our model also predicts a significant effect of the arrangement of dopant cations on the electrolyte conductivity.