Ideal Pore Size Research Articles

Wetting of Ni and NiO by Alternative Molten Carbonate Fuel Cell Electrolytes. II. Influence of the Electrode Overpotential

As a continuation of the investigation of Ni and lithiated NiO single‐crystal wettability by alternative electrolytes for molten carbonate fuel cells (MCFCs), the increment of contact angles has been studied when anodic or cathodic overpotential, respectively, was applied to these solids. This investigation was carried out at 650°C under hydrogen‐ or oxygen‐containing atmospheres, respectively, within the overpotential ranges corresponding to usual operating parameters of the MCFC stacks. Using contact angle values for NiO single crystals determined in the first part of this investigation, the optimal ratio of anodic to cathodic pore size values for porous MCFC electrodes has been calculated according to the Mugikura‐Selman relationship [Y. Mugikura and J. R. Selman, J. Electrochem. Soc., 143, 2442 (1996)]. When considering in these calculations the contact angle values for smooth, NiO single‐crystal surfaces, one should conclude that the equilibrium of capillary forces should be obtained at quite identical mean pore sizes in both porous electrodes. The electrode polarization should show only negligible effect on this equilibrium. © 2000 The Electrochemical Society. All rights reserved.

Porous polycarbonate phase-inversion membranes

This paper presents a method of preparation of phase-inversion porous polycarbonate membranes as well as experimental data on their structure and transport and separation properties. From a casting solution containing 8% of polycarbonate in a mixture of dioxane and dimethylformamide (mass ratio 3: 2), it is possible to obtain porous membranes by the phase-inversion method. Gelation should be carried out in an atmosphere of air saturated with water vapour. The porosity of the membranes can be controlled by the time and temperature of gelation. The obtained membranes are reasonably symmetrical, having a spongy structure with identical pore sizes and a skinned external structure. They retain macromolecules and suspended substances to a degree which depends on the nature of the solutes and on the pressure.