Prior to analysis of the local structure of K + within the samples, electrochemical properties and ex-situ structural analysis was performed to identify any informative structure-function properties that may enhance our analysis of the potassium K-edge XANES. The PB samples of high crystallinity (HC-PB) and low crystallinity (LC-PB) can both be assigned by XRD to crystalize with a face-centered Fm3 � m PB structure, with varying average crystallite sizes of 103 ±3 nm and 14 ± 2 nm, respectively (Figure and Table ). IR spectroscopy further confirmed the formation of PB through the presence of a single ν(C≡N) mode at 2086 cm -1 (HC-PB) and 2081 cm -1 (LC-PB), as shown in Figure . The morphology of the two samples is notably different when imaged with scanning electron microscopy (SEM) (Figure ), with HC-PB comprised of 140 ± 30 nm faceted crystalline particles, and LC-PB of ill-defined <18±4 nm particles that agglomerate into >10 µm aggregates. Notably, the large aggregates of LC-PB proved harder to disperse amongst the conductive carbon black during electrode preparation (Figure ).