Mapping the Distribution of Doping Elementsin Electrolytically Doped Manganese Dioxideby EFTEM and EELS

Summary.  Energy-filtering transmission electron microscopy (EFTEM) and electron energy-loss spectrometry (EELS) have been used to measure the distribution of titanium in titanium-doped electrolytic manganese dioxide, which consists of large particle agglomerates of some micrometer diameter. In contrast to previous investigations, where the distribution of the doping elements can only be investigated at the thinnest regions of the agglomerates, we describe an improved procedure which allows to measure the concentration of the dopant not only at the thinner edges of the particle agglomerate, but also in the interior. The titanium distribution maps showed that titanium is enriched on the surface of the agglomerates and in pores penetrating into their interior. Within the agglomerates, titanium is evenly distributed, and in manganese dioxide the titanium concentration could be analyzed quantitatively by EELS spectrometry. Based on these results, suggestions for possible improvements of the doping process and for the preparation of the product are given. Received November 29, 2000. Accepted (revised) December 12, 2000