Characterization of Fuel Cells

Cathode Lao.sSro.sMnOs + Pt(0.5 wt%) Lao.6Sro.4Co03 Ceramic 

The V-I characteristic of a single cell A is shown in Fig. 14.8(a). Although the power density has not reached the target, it is proved that the HMFC concept works without any serious problems. The cell resistance was divided into an IR resistance and a polarization resistance by the AC impedance method. The composition of cell resistance is shown in Fig. 14.8(b). The polarization resistance is further analyzed by an AC impedance method because it is difficult to introduce a reference electrode to a fuel cell with a thin-film electrolyte [12]. AC impedance spectra were measured for various Ph2 of anode side and Pq2 of the cathode side to determine the polarization (Fig. 14.9). In all conditions, two polarization semicircles were seen. One semicircle has a peak around 3 kHz (Ra), and the other has a peak around 30 kHz (Rb). Both of these are affected by Po2 of cathode gas, and none of these is affected by Ph2 of anode gas. So, both Ra and Rb correspond to the cathode polarization, and the anode polarization is very small compared to the cathode polarization. As mentioned, Pd has very high hydrogen permeation capability, and it is reasonable that Pd has high activity as a fuel cell anode. The Po2 dependence of Ra and Rb is analyzed 

Either step 2 or 3 is most likely to be the rate-determining step [13]. In the case of HMFC, the polarization Ra can correspond to step 3 and the polarization Rb can correspond to step 2 from P02 dependence analysis. 

Although the cathode material used in our fuel cell is popular in SOFCs, the cathode polarization is much smaller than that reported in SOFC literature using bulk electrolyte [14]. Hibino et al. also reported anode and cathode polarization of fuel cells using a perovskite proton conductor as a bulk electrolyte, and the polarization was much larger than our result [15]. These facts suggest that electrolyte thickness may affect the polarization. 

Temperature °C Anode gas Cathode gas Measured OCV mV Theoretical voltage mV Transport number 

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PTC 50 ASME Performance Test Code - Will provide test procedures, methods and definitions for the performance characterization of fuel cell power systems. 

ASME PTC 50 ASME Performance Test Code 50 - Fuel Cell Power Systems provides test procedures, methods and definitions for the performance characterization of fuel cell power systems. The code specifies the methods and procedures for conducting and reporting fuel cell system ratings. Specific methods of testing, instrumentation, techniques, calculations and reporting are presented. This standard is currently being drafted and is expected to be approved and published in 2002. 

It has been demonstrated that EIS can serve as a standard analytical diagnostic tool in the evaluation and characterization of fuel cells. Scientists and engineers have now realized that the entire frequency response spectrum can provide useful data on non-Faradaic mechanisms, water management, ohmic losses, and the ionic conductivity of proton exchange membranes. EIS can help to identify contributors to PEMFC performance. It also provides useful information for fuel cell optimization and for down-selection of the most appropriate operating conditions. In addition, EIS can assist in identifying problems or predicting the likelihood of failure within fuel cell components. 

Fourier transform infrared (FTIR) and in-situ FTIR spectroscopy are among many modern instrumental tools of analytical chemistry well established in fuel-cell-related electrochemistry [1]. In general, FTIR spectroscopy is a valuable tool in the characterization of fuel cell technical electrodes, where the nature of surface groups can be identified, since such electrodes are rather difficult solid surfaces on which to work. FTIR is among the methods less commonly used for the characterization of dispersed catalysts and supports, but as a technique is able to give an idea about the nature of the surface groups on carbon supports and on the structure of adsorbed species on noble metal clusters. 

FTIR spectroscopy has been shown to be a useful tool in the characterization of fuel cell model catalysts. It has helped elucidate much information on the electronic and geometrical structure of surfaces, which may help in the explanation of unusual size effects on electrocatalysis. Surface diffusion of the adsorbed molecules has been seen from time- and potential-dependent IR spectroscopy showing that the oxidation of CO on Pt sites and Ru sites are coupled. There is... 

Electrochemical Characterization of Fuel Cells—Correlation Between EIS and Current/Voltage Characteristic of Fuel Cells. The performance of a fuel cell depends not only on electrochanical properties of the electrode/electrolyte... 

More, K. (2011) Characterization of fuel cell materials. Presented at the DOE Hydrogen Program Merit Review and Peer Evaluation, Washington, DC, 10 May 2011. 

Yuh CY, Selman JR (1988) Characterization of fuel cell electrode processes by AC impedance. AlChE J 34 1949-1958... 

Physical characterization of low-temperature fuel cell catalysts is very important for the exploration and preparation of novel catalysts. The emergence of some new techniques, like electrochemical mass spectroscopy (EMS), and continuing progress in some traditional techniques, like SEM and TEM, will effectively improve the characterization of fuel cell catalysts. 

Maish, A., E. Nilan, and P.M. Baca. 2002. Characterization of fuel cell duty cycle elements. Albuquerque, NM Sandia National Laboratories. 

Characterization of fuel cells covers an extremely wide range of measuring systems and applied techniques and methods. Therefore, we need to specify our understanding of characterization in the sense of this chapter. 

Morita H, Yoshiba F, Woudstra N, Hemmes K, Spliethoff H (2004) Feasibility study of wood biomass gasification/molten carbonate fuel cell power system-comparative characterization of fuel cell and gas turbine systems. J Power Sources 138 31-40... 

Characterization of Fuel Cells and Fuel Cell Components... 

Diagnostic Methods or Techniques for Characterization of Fuel Cells or Components and Parameters Measured... 

ASME FTC-50 Fuel Cell Power Systems Performance, (ASME 2000) Scope This Code provides test procedures, methods, and definitions for the performance characterization of fuel cell power systems. Fuel cell power systems include all components required in the conversion of input fuel and oxidizer into output electrical and thermal energy. Performance characterization of fuel systems includes evaluating system energy inputs and electrical and thermal outputs to determine fuel-to-electrical energy conversion efficiency and, where applicable, the overall thermal effectiveness. These efficiencies will be determined to an absolute uncertainty of less than 2% at a 95% confidence level. (For example, for a calculated efficiency of 40%, the true value lies between 38% and 42%.) This Code applies to all fuel cell power systems regardless of the electrical power output, thermal output, fuel cell type, fuel type, or system application. 

Gupta, K. and Jena, A. (2003) Techniques for pore structure characterization of fuel cell components containing hydrophobic and hydrophilic pores. Presented at the 2003 Fuel Cell Seminar, Miami Beach, FL, Abstract pp. 723-726, November 3-7, 2003. 

Eckhard, K., Schuhmann, W. Localized visualization of O2 consumption and HjOj formation by means of SECM for the characterization of fuel cell catalyst activity. Electrochim. Acta 2007, 53, 1164-1169. 

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