Single Cell Performance

But when the contents of Nafion ionomer was increased from 30 to 45 % to find out the better electrode structures, the Pt-Ru/SRaw, which had showed the lowest single cell performance, became the best electro-catalyst. By this result one can conclude that as long as the structure of the electrode can be optimized for the each of new electro-catalysts, the active metal size is a more important design parameter rather than inter-metal distances. Furthermore, when the electro-catalysts are designed, the principal parameters should be determined in the consideration of the electrode structures which affect on the electron conduction, gas permeability, proton conductivity, and so on. 

Figure 3.3 Single cell performances of catalysts supported on various CNFs (a) T-CNF, (b) P-CNF, (c) thick H-CNF, (d) very thin H-CNF and (e) E-TEK catalyst. CNE-supported catalysts, Pt-Ru 40wt% (Pt 1.33, Ru 0.67 and CNE 3 mgcm ) E-TEK catalyst, Pt-Ru 60wt% (Pt 2, Ru 1 and CNE 2mgcm ).

Figure 3.6 (a) l-V curves and (b) single cell performances of Pt-Ru 40wt% catalysts supported on as prepared H-CNF, nanotunneled H-CNF and 60wt% E-TEK catalyst examined at 30, 60 and 90°C. 

The single cell performance of the catalyst supported on nanotunneied mesoporous H-CNE was found to be affected by the pH used in the impregnation procedure, which was controlled by adding 1 M NaOH solution. The highest maximum power density of 169 mWcm was produced with the catalyst obtained at pH 3-4. Accurate control of the pH in the impregnation procedure is therefore an important factor for improving the catalytic activity. 

The single cell performance and the maximum power density of the Pt-Ru 40 wt% catalyst supported on thin H-CNF are shown in Figure 3.8. The maximum power densities were 76, 140 and 246mWcm at 30, 60 and 90°C, respectively. The present nanodispersion treatment is therefore very effective in dispersing thin CNFs. 

Figure 3.8 Single cell performance of the catalyst supported on highly dispersed thin H-CNF examined at 30 60 and 90 C.

FIGURE 3.5 Single-cell performance curve using Sc-doped zirconia electrolyte. 

TiO2, and casting. The results for water uptake, lEC and single cell performance were compared with the commercial Nafion-115 and home-made, recast Nafion membranes. Power density values of 0.51 and 0.26 Wcm at 0.56 V were obtained at 110 and 130 °C, respectively, for the composite Nafion-titania membrane [46]. 

Zhang et al. [128] synthesized a self-humidifying membrane based on a sulfonated poly(ether ether ketone) (SPEEK) hybrid with a sulfated zirconia (SO / ZrO2, SZ) -supported platinum catalyst (Pt-SZ catalyst). This type of composite membrane has a higher proton conductivity than plain SPEEK, due to the effect of the Pt-SZ catalyst the membrane also provided excellent single cell performance at low humidity. 

Fig. 2 Single cell Performances of DMFCs with different cathode catalyst. Operation conditions temperature 50, MeOH IM and O.lcc/min, Air flow 52.5cc/min...

With nano-SDC infiltrated LSM cathode, the single cell performance was obviously improved. Our micro-stack results proved that the gas flow geometry critically affects the stack performance. The performance of linear micro-stacks decreased with increasing cell number, probably due to the uneven gas/temperature distribution. The symmetric star-shaped design exhibited attractive output, making it very promising for portable power sources. 

P. Lunghi and S. Ubertini, First Steps Towards Fuel Cells Testing Harmonization Procedures and Parameters for Single Cell Performance Evaluation, Vol. 3, Suppl. 4,... 

Fig. 20 Single cell performance comparison. Conditions cell temperature 80 °C, H2 chiometry 1.5, 02/air stoichiometry 9.5/2.0, both fuel and oxidant reactant gases humidified, ambient pressure. Ohmic resistance was determined using auxiliary current pulses according to [214]...

Another prorrtising modification of PBI is the introduction of immobilized polyvirtylphosphonic acid (PVPA) in the PBI matrix. This approach is especially interesting since the acid is not likely to be washed out dttring operation, thus maintaining steady fuel cell performance. PEMEAS-BASF Fuel Cells has developed an MEA product, Celtec -V, mainly for liqttid feed DMFCs, based on this concept Single-cell performance tests of CeltecV and Na... 

The aforementioned polymeric electrolytes have been effectively used in polymer electrolyte fuel cells operating up to In order to study the single cell performance and apart from the high ionic conductivity of the membrane, several parameters residing the MEA constmction must be taken into account in order to have optimum performance of the cell. Some of these parameters are the amount of the catalyst the ionomer-binder used at the electrodes and its percentage, electrode surface and the preparation method, pressure and the temperature of the MEA assembling and design and constmction parameters of the cell. ... 

Liu et al. prepared carbon-supported zirconium oxynitride (ZrO jNy/C) by ammonolysis of carbon-supported zirconia (Zr02/C) at 950°C [81]. The onset potential of the TxO ylC for the ORR was 0.7 V vs. RHE, and the four-electron pathway for the ORR was achieved on the surface of the ZrO cN3,/C. The maximum power density of the single cell using the ZrO N C as a cathode at 80°C was 50 mW cm, which was much lower than that of a single ceU using commercial Pt/C as a cathode. The enhancement of the catalytic activity is required to obtain a superior single cell performance. 

Tungsten carbide based non-Pt electrocatalyst have been evaluated for single cell performance of PEMFC. The power densities of WC/C (1 mg/cm ) and Ni-WC/C (1 mg/cm ) anodes fabricated by TPRe were 6.5 and 8.9 mW/cm, respectively, cathode of 20 wt% Pt and membrane of Naflon 117 (151). W2C (0.48 mg/cm ) anode catalyst was prepared by ball-milling of WO3, Mg, and C mixture and tested in a single cell mode at 80°C with Pt/C cathode (0.3 mg/cm ), Naflon 112 membrane, and H2/Air = 5. This electrocatalyst produced high current densities of 240 mA/cm (at 2 atm) and 280 mA/cm (at 3 atm) at 0.5 V, and an open circuit voltage of 0.95 V(152). These values represent the highest current density reported for WC-based anode in the literature. In the analysis, the material... 

Figure 7-24 Single Cell Performance of LSGM Electrolyte (50 p,m thick)... 

Single Cell Performance of PBI/ PTFE/H3PO4 Based MEAs... 

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