Tomographic 3D Analysis of Reduction Displacement Reaction with Associated Formation of a Conductive Network in High Energy Primary Batteries

Hybrid Ag2VO2PO4-CFx battery electrodes with high energy and pulse performance were investigated in regards to their structural and morphological changes during electrochemical discharge. Reduction products of CFx and Ag2VO2PO4, carbon and Ag0, respectively, were identified via bulk laboratory X-ray diffraction and were characterized further by SEM-EDS to identify variations in Ag2VO2PO4-Ag0 agglomerate distributions in the electrode. X-ray tomography was used to characterize the statistical formation and redistribution of these agglomerates at a higher discharge state. Using this technique, we observed the agglomerates within the electrode to increase from 20–40 μm3 to larger sizes (>500 μm3) upon discharge. These data were used to rationalize the changes in conductivity of the composite material upon galvanostatic discharge, as determined under high rate pulsatile discharge and impedance spectroscopy. Both volumetric and spatial redistribution of the materials identified in this study provides insight toward the development and understanding of future high energy and high power primary batteries.