Fig. 3: Effect of anion pinning and applied voltage sequences on the scattering profile of Ni3(HITP)2 electrodes.
a SAXS data of Ni3(HITP)2 in the dry state (black) and wetted with 1 M NaTFSI at 0 V (grey), + 0.4 V (red), and − 0.4 V (blue) applied cell voltage. The corresponding best fitting form factors |F(q)cyl.|2 for the dry and filled states are included as dashed and dotted lines, respectively. The inset highlights the 220 and PTFE peaks. b Schematic representation of the pore filling and electron density profiles for the dry and wetted states, indicating the formation of a core-shell electrolyte distribution with a TFSI--rich layer of about ~ 0.25 nm thickness along the MOF pore wall. The top right provides a sketch of a TFSI- ion in cis-configuration showing approximate dimensions with atoms represented as blue for nitrogen (N), orange for sulphur (S), red for oxygen (O), grey for carbon (C), and yellow-green for fluorine (F).c Cyclic voltammograms (CVs) recorded at 1 mV/s before (94 F/g, dark green) and after (104 F/g, light green) the chronoamperometry (CA) steps. d Cell voltage (top panel) showing CV and CA cycles, with time-resolved data for the average relative scattering intensities at low-q between 0.34 and 0.64 nm−1 and relative peak intensities of selected peaks (200, 210, 300, 220 and PTFE).
