论文标题
带电表面对聚合物电解质的结构和动力学的影响：原子模拟的见解
Impact of Charged Surfaces on the Structure and Dynamics of Polymer Electrolytes: Insights from Atomistic Simulations
论文作者
论文摘要
在下一代锂离子和锂金属电池中，对聚合物电解质进行了深入研究，以用作固体电解质。但是，对于接近电极表面的聚合物电解质的结构和动力学特性知之甚少。在这里，通过分子动力学模拟研究了一个限制在两个相对带的石墨样电极之间的PEO-LITFSI聚合物电解质。 $σ_s= 0 $，$ \ pm 0.5 $和$ \ pm 1 $ $ e $/nm $^2 $的三种不同的表面费用。充电后，观察到非常强大且特定于成分的分层。仅对于最高的表面电荷，锂离子才能脱落并直接与负电极接触。该层结构与自由能屏障的出现相伴，这会导致锂离子动力学的降低，这是通过空间分辨的均方根位移量化的，对漂移组件进行了校正。已知对于聚合物电解质中远程锂离子转运非常重要的链转移对于不同层之间的锂离子的过渡没有重要作用。
Polymer electrolytes are intensely investigated for use as solid electrolytes in next generation lithium-ion and lithium-metal batteries. However, little is known about the structural and dynamical properties of polymer electrolytes close to electrode surfaces. Here, a PEO-LiTFSI polymer electrolyte, confined between two oppositely charged graphite-like electrodes, is studied via molecular dynamics simulations. Three different surface charges of $σ_S = 0$, $\pm 0.5$ and $\pm 1$ $e$/nm$^2$ are considered. Upon charging, a very strong and component-specific layering is observed. Only for the highest surface charge, lithium ions get desolvated and come into direct contact with the negative electrode. The layer structure goes along with the emergence of free energy barriers, which lead to a reduction of the lithium-ion dynamics, as quantified by spatially resolved mean square displacements, corrected for a drift component. Interchain transfers that are known to be very important for long-range lithium-ion transport in polymer electrolytes play no significant role for transitions of lithium ions between different layers.
