In Situ La, Ce, and Nd L‐Edge X‐Ray Absorption Fine Structure Study of an Intermetallic Metal Hydride Electrode in an Operating Alkaline Battery

Abstract

The x-ray absorption fine structure of a technologically important MmL5 intermetallic compound (Mm = Lao.52Ceo.34Ndo.loPro.o4, L5 = Ni3.sCao.sMno.3AIo.4) in the form of a hydrogen storage cathode was recorded in situ in the region 5440-6290 eV using an electrochemical cell which is essentially a fully functioning alkaline battery. Significant differences were observed in the x-ray absorption near edge structure (XANES) of all of the absorption edges (La, Ce, and Nd) between the uncharged and fully charged states. In particular, a clear increase in the intensity of the La and Nd L,cedge resonances (due to 2P3/2 --> 5d electronic transitions) was found upon charging the cell. This phenomenon was attributed to an increase in the density of empty d-like states near the Fermi level following hydrogen injection into the lattice. Furthermore, the behavior of the Ce L,.,j-edges of this battery material upon charging was nearly the same as that observed for the gas phase hydrogenation of the Ce2Fe17 and Ce2Fe~4 B intermetallics reported in the literature.

Electronic Structure of the CO/Pt(111) Electrode Interface Probed by Potential-Dependent IR/Visible Double Resonance Sum Frequency Generation Spectroscopy

“…Techniques to probe the electronic structure at solid/liquid interfaces in situ are, however, still limited. Second harmonic generation (SHG) spectroscopy is one solution to probe the surface electronic structure; however, the spectroscopic SHG study is rather limited, and the interpretation of the results is not straightforward. − X-ray absorption near edge structure (XANES) can prove the oxidation state of elements − and electronic states at the electrode/electrolyte solution interface . We recently developed an in situ electrochemical X-ray photoelectron spectroscopy (XPS) system combined with a specially designed electrochemical cell with a thin (ca.…”

Ion exchange and fixation of rare-earth cation into expandable tetrasilicic fluorine mica

“…Simultaneously, the absorption maxima slightly shift to the lower energy side as the calcination temperature increases (in the inset of Fig.3). This type of phenonmena can be partially attributed to a decrease of the density of empty d-like states near the Fermi level following Nd migration into the silicate lattices Tryk et al, 1995). As noted before, a surplus negative surface charge of octahedral layers is transfered into cationic Nd ions as they are migrated into vacant octahedral sites upon calcination.…”

In Situ Raman Spectroscopy on an Operating AA Zn-MnO[sub 2] Battery under High Discharge Currents

“…Although the electrochemical behavior of Zn anodes in strongly alkaline solutions has received considerable attention both from industrial and academic communities, 1-5 the extent to which the information so far reported may be relevant to an actual operating battery still remains to be determined. Recent efforts in our research group have been aimed at implementing spectroscopic techniques for probing electrodes under conditions which closely mimic those found in real electrochemical devices, 6 in an attempt to avoid such ambiguities. This paper presents a new methodology for the acquisition of in situ Raman spectra of a real Zn anode in a genuine battery environment as a function of time, during high-current discharge.…”