Abstract：
Lithium (Li)-ion permeability of holey graphene (hG) for use as an electrically conducting scaffold in solid-state battery electrodes is explored through the means of a particle dynamics simulation model. While carbon materials do not typically exhibit Li-ion conductivity, the unique structural motif of hG, which consists of two-dimensional nanosheets with arrays of through-thickness holes, may present an opportunity for Li-ion conductors (i.e., solid electrolyte (SE) particles) to make contacts through the holes. In our model, the SE is presented as a system of hard elastic spheres conductive to Li-ions. The SE spheres are in contact with each other through compression between two plane current collectors. One hG layer is inserted between the current collectors and parallel to them. Randomly distributed circular holes in the hG allow for contact between the SE particles on both sides of the hG layer. By solving the Li-ion conducting network formed between the electrodes through the contact points of all the particles, the overall conductivity of the system was calculated as a function of SE particle size and the size and number of the hG holes (i.e., hG porosity). A critical ratio of around 4 between the SE particle size and the pore size was found. Below this critical value, the hG layer becomes practically transparent for Li-ions. This study helps to guide the design of highly efficient solid-state electrode composition and architectures using hG as a unique electrically conducting scaffold.
摘要：
通过粒子动力学模拟模型探索了多孔石墨烯（hG）在固态电池电极中用作导电支架的锂（Li）离子渗透性。虽然碳材料通常不具有锂离子导电性，hG独特的结构基序，它由具有贯穿厚度的孔阵列的二维纳米片组成，可能为锂离子导体(即，固体电解质（SE）颗粒）通过孔进行接触。在我们的模型中,SE表示为导电锂离子的硬弹性球系统。SE球体通过两个平面集电器之间的压缩而彼此接触。一个hG层插入在集电器之间并与其平行。hG中随机分布的圆孔允许hG层两侧的SE颗粒之间的接触。通过解决通过所有颗粒的接触点在电极之间形成的锂离子导电网络，系统的总电导率计算为SE粒径以及hG孔的大小和数量的函数(即，HG孔隙率)。发现SE粒度和孔径之间的临界比率约为4。低于这个临界值，hG层对于锂离子实际上变得透明。这项研究有助于指导使用hG作为独特的导电支架的高效固态电极组合物和架构的设计。
