PFG NMR measurements use gradient pulses to encode and decode the position of nuclear spins. If the positions of nuclei change during the experiment, e.g. because of self-diffusion, the signal measured at the end of the experiment decreases . This signal attenuation becomes more pronounced at higher gradient strengths, allowing the diffusion coefficient to be determined by varying the gradient strength and fitting the resulting data. Initially, ACC-15 saturated with 1 M TEABF4 (ACN) was studied using an intermediate diffusion time (85 ms). Diffusion 19 F PFG NMR measurements reveal two components in the in-pore anionic environment (Figure ). The dominant slow-diffusing component (Figure ,c, blue component) corresponds to ionic diffusion within the porosity, influenced by electrolyte/surface interactions, pore connectivity, and geometry. This component reflects the intrinsic transport properties of the electrode material. In contrast, the faster-diffusing component (Figure ,c, magenta component) arises from anions undergoing chemical exchange between in-pore and ex-pore environments during the diffusion time. This reflects the residence time of the electrolyte within carbon particles, which varies with particle packing and particle size , but does not represent the intrinsic electrode properties and is therefore not analyzed further. Unlike prior work , no external potential was applied, so the effective diffusion coefficients reflect the ease of ionic transport in the porosity without contributions from electrostatic interactions during charging/discharging.