Employing PCA and Rietveld refinement on X-ray diffraction data to explore and quantify the crystalline phases in the cathode of depleted Zn-MnO2 alkaline batteries

A combined approach of the principal component analysis (PCA), a method of processing multivariate data, and Rietveld refinement on X-ray diffraction (XRD) data were employed to analyze the crystalline phases present in samples extracted from the cathode's internal and external surfaces of a depleted Zn-MnO2 alkaline primary battery. PCA allowed discrimination of the cathode surface region where the samples came from (six regions), inferring the number of crystalline phases of the samples and the relative concentrations as a function of the sample region. The PCA results were afterward confirmed by crystallographic analysis of the X-ray diffraction data. Rietveld refinements carried out on the X-ray diffractograms furnished the relative weight of the identified phases in the samples of the two cathode surfaces.