Correlation of Ionic Conductivity with Intersurface Phenomena in Superionic-Conductor-Superlattice

超离子-导体-超晶格中离子电导率与界面现象的相关性

基本信息

批准号：
01540267
负责人：
KOBAYASHI Michisuke
金额：
$ 1.15万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

A computer simulation by a molecular dynamics method at constant volume has been performed to a model system which is composed of accumulating two different ionic conductors :・・・AgI-Ag_2S-AgI-Ag_2S・・・. Along the c-axis (z-axis), AgI-parts are compressed and Ag_2S-parts are stretched. About 3% of Ag ions in Ag_2S-parts have been transfered to AgI-parts. The self-diffusion coefficient of Ag ions in AgI-parts decreases by 40-50 % compared with that in a single AgI-system, while the diffusion coefficient of Ag ions in Ag_2S-parts increases by 30 % compared with that in a single Ag_2S-system. The ionic conductivity of the superlattice-system is larger than that of either material of the AgI-system or Ag_2S-system. The calculation suggests the possibility of the existence of a new material which has a larger ionic conductivity.In this calculation, the newtonian equations of motion of the particles in a fixed MD cell of volume V have been solved numerically. The total energy E has been conserved, and thus the ensemble generated by the simulation is the microcanonical or (E,V,N) ensemble. But these conditions of simulation are not the same as those normally encountered in experiments. The usual experiments are performed under conditions of constant temperature and constant pressure or (T,P,N) conditions. Then we are now performing the MD calculation at constant pressure to the superionic superlattice-system, with also considering the electronic polarizability of anions.

通过恒定体积的分子动力学方法进行了计算机仿真，该模型已对模型系统进行，该模型系统由累积的两个不同的离子导体组成：・・AGI-AG_2S-AGI-AGIAG_2S ・・・・。沿着C轴（Z轴），AGI-PART被压缩并拉伸AG_2S零件。 AG_2S零件中约3％的Ag离子已转移到AGI-PART。与单个AGI系统相比，AGI-PARTS中Ag离子的自扩散系数降低了40-50％，而与单个AG_2S系统相比，AG_2S-PARTS中Ag离子的扩散系数增加了30％。超晶格系统的离子电导率大于AGI-System或AG_2S系统的材料的离子电导率。该计算表明存在具有较大离子电导率的新材料的可能性。在计算中，在数值V的固定MD单元格中，粒子的牛顿运动方程已被数值求解。总能量E已得到保守，因此模拟产生的集合是微型人或（E，V，N）集合。但是，这些模拟条件与实验中通常遇到的情况不同。通常的实验是在恒定温度和恒定压力或（T，P，N）条件下进行的。然后，我们现在要以恒定压力对超级离子超级晶格系统进行MD计算，还考虑了阴离子的电子极化性。