Cathodes, scanning electron microscopy

The structures of the thick anodic and cathodic films produced from the working solutions with active additives and without them as well as the structure of the thin anodic film deposited from the TFE solution have been studied using scanning electron microscopy. The thin anodic film produced from the TFE solution without additives (Fig. 2, a) is porous and consists of small crystals. The... 

Exchanged zeolites were characterized by N2 adsorption at 77K, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), immersion calorimetry and NHs-temperature programmed desorption (NH3-TPD). X-ray diffraction patterns (XRD) were obtained with a JSO Debye-Flex 2002 system, from Seifert, fitted with a Cu cathode and a Ni filter, using CuXa radiation (A,=1.5419) and 2°min of scanning rate. X-ray photoelectron spectroscopy (XPS) spectra were acquired with a VG-Microtech Multilab 3000 spectrometer equipped with a hemispherical electron analyzer and Mg Ka (1253.6 eV) 300W X-ray source. 

Scanning electron microscopy (SEM) scans over a sample surface with a probe of electrons (5-SO kV). Electrons (and photons), backscattered or emitted, produce an image on a cathode-ray tube, scanned synchronously with the beam. Magnification of 20-50,000 are possible with a resolution of about 5 nm. There is a very high depth of field and highly irregular structures are revealed with a three-dimensional effect. 

Figure 12.9 Cross-sectional field emission gun-scanning electron microscopy image of a used membrane electrode assembly. The anode is on the left-hand side, the cathode on the right-hand side. (Adapted from ref. 266, with permission from the Electrochemical Society.)...

Figure 3. Structure of the first Ukrainian thin film zirconia ceramic fuel cell transformer. Left part of the picture shows the LSM cathode of around 10 pm thickness and its surface followed by the dense solid YSZ electrolyte of60-70 pm thickness with a few isolated pores the right part shows the highly porous zirconia—Ni anode. Scanning electron microscopy, Superprobe...

GD sources can be applied as a preparation tool for surfaces prior to scanning electron microscopy (SEM) observation [48]. Despite the collisions, most bombarding ions in an analytical GD hit the cathode within a few degrees of normal incidence [44] and there is very little effect on the sputtering yield over this range of angles. 

In another investigation [17] it was shown by metallography, X-ray microprobe analysis and scanning electron microscopy that the cathodic incorporation of hafnium into copper primarily yields a HfCu4 compound at the electrode surface. Cu-Hf alloy formation is possible, by electrochemical deposition and also by interdiffiision of the metals. 

Fig. 11.7 Scanning electron microscopy (SEM) cross section of an MEA of which 8% wt of the cathode carbon-support had been corroded (see also Fig. 11.6). The initial cathode electrode thickness was identical to the anode electrode thickness shown in the picture (Reproduced from H.A. Gasteiger et al. [3] by permission from Springer)...

Chapter 3, by Chen and collaborators, concentrates on the spectroscopic investigation of the SEI layer on anodes as well as cathodes of LIBs, including the nanometer-sized SnO anode, and the nano-MgO modified LiCoOa cathode. The effect of nano scaled materials on the performance of LIBs is well discussed using combination of spectral techniques, such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), surface enhanced Raman scattering (SERS), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). 

The current density reaches a maximal value when the ohmic or HFR resistance is minimal. At this time, the membrane at the cathode side is almost saturated and additionally produced water cannot be totally absorbed and thus begins to flow and to freeze in the CCL. However, no ice is formed at the anode catalyst layer (ACL). This has been observed in the literature by different means scanning electron microscopy (SEM) (Thompson, 2008a), MEA layers hydrophobicity (Oszcipok, 2005) and visual observations (Ge and Wang, 2007b). 

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