In accordance with the dramatic capacity loss seen for LC-PB, the Δ edge step, which corresponds to the change in un normalized potassium K-edge XANES edge step during charge/discharge, decreases by 54% over 7 cycles (Figure ). In LC-PB, the edge step values show a different trend to that observed for HC-PB on repeat cycling, with the maximum and minimum K + concentrations both converging on a relatively stable PB plateau. By contrast K + signal only decreased in respect to a loss of fully intercalated PW sites on cycling. LCF analysis (Figure ) of the LC-PB data shows a dramatic loss of K + signal variation associated with either electrolyte or PW as CV cycling progresses, with complementary increase of a signal associated with K + trapped within the PB structure. The entrapment of K + within an PB environment throughout the potential sweeps showed that LC-PB becomes electrochemically inactive. A loss of conductivity due to the collapse of the short-range order within PB and ferrihydrite formation (Section 2.1) explains the observed trapping of charge carriers in the remaining PB sites within the cathode.