Defect Topology Governs Lithiation Pathways in Graphite Anodes

The electrochemical behavior of graphite anodes is strongly affected by structural disorder, yet graphite crystallinity is often described using averaged descriptors that do not resolve the underlying defect landscape. Here, we investigate a series of industrially relevant graphite samples combining high‑resolution synchrotron x‑ray diffraction with FAULTS‐based analysis of planar defects and operando measurements. We show that graphites with similar average crystallographic signatures span distinct defect‑topology regimes defined by different combinations of stacking faults, rhombohedral (3R) intergrowths and turbostratic interlayers. Operando diffraction reveals that lithium insertion does not initiate within an ideal 2H host, but proceeds preferentially through stacking‑faulted and 3R‑related environments, which provide structurally accessible insertion pathways. In contrast, turbostratic interlayers do not participate in early lithium insertion and correlate with reduced reversible capacity. These results demonstrate that graphite behavior is governed by defect topology rather than by a single degree of disorder and highlight the need for defect‑resolved structural descriptors to rationalize lithium intercalation mechanisms in graphite.