... demonstrated promising performance at higher current densities (0.2 and 0.3 mA cm −2 ) and with various organic electrolytes. The superior performance of GNS-1 can be ascribed to its higher mesopore volume, SSA, and optimum wettability compared to its counterparts. The morphology of synthesized GNSs...

... 27, 2013; final manuscript received August 28, 2015; published online September 18, 2015. Editor: Wilson K. S. Chiu. 27 11 2013 28 08 2015 PEMFC hydrogen pressure pulsation feed current density effective diffusivity A fuel cell is an electrochemical device which...

... fuel cells (PEMFCs). Effects on the current density, temperature difference, and water content have been simulated and analyzed, respectively, with conventional and interdigitated flow field when the humidification in the anode or cathode is from 25% to 100%, respectively. The numerical results show...

... specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. Tafel plot shows the highest exchange current density value of 10 − 2.05 mA cm 2 for MEA with 0.5 mg/cm 2 catalyst loading tested at reactant gas...

...Markus J. Heneka; Ellen Ivers-Tiffée In this contribution, the performance of solid oxide fuel cells (SOFC) under high current density load cycles is studied by means of electrical measurements and material analyses. Our study is an important premise for the application of accelerated life testing...

... was the current density and temperature profile across the MT-SOFC that was strongly dependent on the distance from the hydrogen/fuel inlet. Not only was the model validated but also a grid and quantitative solution analysis is explicitly shown and discussed. This resulted in the optimum grid density...

...-dimensional, simultaneous, partial differential equations of mass, energy, and electrochemistry and neglecting the stack direction variation effect, is developed. The results show that the fuel utilization increases with a decrease in the molar flow rate, and the average current density decreases when...

... of the major performance limiting conditions. A pseudo-two-dimensional analytical model is developed to predict the inception of two-phase flow along the length of the cathode channel. The diffusion of the water is considered to take place only across the gas diffusion layer (GDL). The current density...

... Laboratory (PNNL). The activation overpotential was investigated through the exchange current density term, which is dependent on the cathode activation energy, the cathode porosity, and the pore size and grain size at the cathode triple phase boundary. The cathode pore size, grain size, and porosity were...

... of polymer electrolyte membrane fuel cell stacks, and more particularly, on the current distribution along the cell. The oxygen concentration decreases along the channel and induces a change in the local electrochemical response; it means that the local current density on the cell is redistributed...

... variables are cell humidity, pure oxygen or air as oxidizer, and current density. Three groups of single cells were tested: a graphite cell, a stainless steel cell (treated and original), and a thin, small, treated stainless steel cell. A treated cell here means using an electrochemical treatment to improve...

..., current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also...

... locations in the stack. The ac impedance analysis, also known as electrochemical impedance analysis, showed low frequency inductive effects and mass transport losses due to liquid water accumulation at high current densities. Results show that the stack run time to achieve steady state for impedance...

...). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode manifold. Three different inlet configurations were tested: plug flow, circular inlet, and a diffuser inlet. A very distinct jet was formed in the manifold, when using the circular inlet configuration, which...

...S. H. Kim; K. B. Shim; C. S. Kim; J. T. Chou; T. Oshima; Y. Shiratori; K. Ito; K. Sasaki The influence of water vapor in air on power generation characteristic of solid oxide fuel cells was analyzed by measuring cell voltage at a constant current density, as a function of water vapor concentration...

... and testing. Low in-plane resistance is extremely important for the ribbon architecture because high in-plane GDL resistance can cause significant variation in current density over the catalyzed area. To reduce the current variation the new GDLs are fabricated with materials that have reduced in-plane...

... flow, mass transport, and electrochemistry are examined. Detailed electrochemical/mass characteristics, such as flow velocities, species mass fraction, species flux, and current density distributions are presented. These details provide a solid basis for optimizing the geometry of a PEM fuel cell stack...

... transfer analysis based on the deformed GDL geometry and modified parameters with the microscale electrical contact resistance analysis. The modeling results reveal that higher assembly pressure increases cell resistance to gas mass transfer, causes an uneven current density distribution, and reduces...

... with a uniform electrolyte current density distribution to make the most efficient use of the available space and possibly to help minimize the onset of cell component degradation. Predicting the electrolyte current density distribution requires an understanding of the many physical and electrochemical processes...

...H. Lustfeld; M. Reißel; U. Schmidt; B. Steffen In this paper the tomographic problem arising in the diagnostics of a fuel cell is discussed. This is concerned with how well the electric current density j ( r ) be reconstructed by measuring its external magnetic field. We show that (i) exploiting...