Fig. 1: Scattering profiles of the dry Ni₃(HITP)₂ MOF electrode in a) SAXS and b) WAXS regions represented by a full black line.

We define “SAXS” and “WAXS” here pragmatically by the q-ranges covered by the two detectors used to collect the signal, with an overlap between 14 and 16 nm⁻¹. The dashed black line in (a) shows the single-step form factor model |F(q)_cyl.|² for infinitely long monodisperse cylindrical pores with diameter D = 1.39 nm. Vertical grey lines represent in-plane (hk0) peaks, orange dash-dotted lines indicate out-of-plane (hkl, l ≠ 0) peaks, and dashed red lines mark stacking peaks (00 l). In-plane peaks from the atomic-scale carbon triphenylene structure are marked by dotted green lines (c-hk0). For clarity, the vertical grey lines in the WAXS pattern are only shown up to 18 nm⁻¹ (see SI, Supplementary Fig. S1 for full picture). The PTFE-binder peak at q = 12.4 nm⁻¹ is not related to the MOF structure. The inset in b, visualised using Mercury 3.7⁵¹, shows the top-view and AB-stacked side view of Ni₃(HITP)₂ with some sets of exemplary families of planes. The zoomed-in section of the inset shows the detailed structure with labelled elements.