Department of Material Science and Engineering, Iowa State University, Ames, 50011, USA.
Phys Rev Lett. 2012 Aug 17;109(7):075901. doi: 10.1103/PhysRevLett.109.075901.
Previously observed non-Arrhenius behavior in fast ion conducting glasses [J. Kincs and S. W. Martin, Phys. Rev. Lett. 76, 70 (1996)] occurs at temperatures near the glass transition temperature, T(g), and is attributed to changes in the ion mobility due to ion trapping mechanisms that diminish the conductivity and result in a decreasing conductivity with increasing temperature. It is intuitive that disorder in glass will also result in a distribution of the activation energies (DAE) for ion conduction, which should increase the conductivity with increasing temperature, yet this has not been identified in the literature. In this Letter, a series of high precision ionic conductivity measurements are reported for 0.5Na(2)S + 0.5[xGeS(2) + (1-x)PS(5/2)] glasses with compositions ranging from 0 ≤ x ≤ 1. The impact of the cation site disorder on the activation energy is identified and explained using a DAE model. The absence of the non-Arrhenius behavior in other glasses is explained and it is predicted which glasses are expected to accentuate the DAE effect on the ionic conductivity.
先前在快速离子传导玻璃中观察到的非 Arrhenius 行为[J. Kincs 和 S. W. Martin，Phys. Rev. Lett. 76, 70 (1996)]发生在接近玻璃化转变温度 T(g)的温度下，归因于离子捕获机制导致的离子迁移率变化，从而导致电导率随温度升高而降低。直观地说，玻璃中的无序也会导致离子传导的激活能分布（DAE），这应该会随着温度的升高而增加电导率，但这在文献中尚未得到证实。在这封信中，报道了一系列高精度的 0.5Na(2)S + 0.5[xGeS(2) + (1-x)PS(5/2)]玻璃的离子电导率测量结果，组成范围为 0 ≤ x ≤ 1。使用 DAE 模型确定并解释了阳离子位置无序对激活能的影响。解释了其他玻璃中不存在非 Arrhenius 行为的原因，并预测了哪些玻璃有望突出 DAE 对离子电导率的影响。
