Local Structural Disorder in FeCl₃-SbCl₅-Intercalated Graphite: Revealing the Disconnect Between Long-Range Periodicity and Nanoscale Intercalant Arrangement

Abstract

Graphite intercalation compounds (GICs) containing metal chlorides exhibit well-defined layer-by-layer periodicity that underlies their electronic and functional properties. However, the local architectures formed during bi-intercalation, particularly in FeCl₃-SbCl₅ graphite bi-intercalation compounds (GBCs), remain largely unexplored. Here, we reveal the nanoscale structural disorder in FeCl₃-GICs and FeCl₃-SbCl₅-GBCs using a combination of X-ray diffraction (XRD) and transmission electron microscopy (TEM). Well-defined odd-stage FeCl₃-GICs show regular long-range staging, whereas subsequent SbCl₅ intercalation disrupts this periodicity, producing GBCs with heterogeneous local intercalant distributions.Direct lattice imaging by TEM, corroborated by XRD, demonstrates that spatial separation of intercalants stabilizes the biintercalated structure. These findings provide new insights into the interplay between long-range order and local disorder, highlighting the importance of nanoscale architecture for understanding and potentially controlling layered intercalation systems.