Operando XANES was used to follow changes in K + speciation within HC-PB between CV cycles 3 and 10 (Figure ), over which time a 15% loss in capacity was observed. While minor shifts in the CV peak positions occurred during HC-PB cycling, the electrochemical properties of the sample remained relatively consistent. Based on the edge step of the unnormalized XANES (Figure ), clear repeatable cycles of K + concentration can be observed. Notably, the plateaus and maxima of K + concentration reduce slightly, by 30%, while the minima remain constant. LCF of the potassium XANES across the repeated cycles is shown in Figure , with the cycling of the three K + environments being relatively consistent as expected. Therefore, it can be concluded that the intercalation sites present, while dropping slightly in absolute number, continuing to effectively cycle between the K + species discussed over the 8 CV cycles investigated. The modest loss of structural order and intercalation sites on cycling of HC-PB, as determined by Fe K-edge EXAFS analysis (Section 2.1), explains the decrease in K + intercalation seen from edge step analysis. Nevertheless, the effective cycling of the remaining K + species shows that sufficient framework order is retained to maintain conductivity and electrochemical efficiency.