Importantly, current understanding of the location of K + in PB is deduced from general long range structural information such as diffraction data, or via theoretical simulation. Herein, we show that operando potassium K-edge X-ray absorption near edge structure (XANES) can successfully be employed to understand, with the aid of theoretical simulations, the local structure of K + in PB cathodes. While XANES has previously been employed to follow sulfur species (at the S K-edge) in batteries during operation, there have been few attempts to monitor group 1 or 2 species in battery cathodes. Villevieille and co-workers have identified different Na K-edge spectra of ex-situ isolated charged and discharged Na x MnO 2 cathodes, while Weatherup and co-workers showed that ex-situ Mg K-edge XANES could be used to identify changes at the solid electrolyte interface of a Mg anode. Yet neither of these studies are performed during battery operation. We show that such XANES studies can be employed simultaneously with electrochemical testing in an operando experiment. Two samples of varying crystallinity and electrochemical stability are studied, and the evolution of K + within the structure monitored over repeated cyclic voltammograms.