Optimisation of Manufacturing Parameters for an Ni–Ag Fuel Cell Electrode

Abstract

Abstract The aim of this research is to optimise manufacturing parameters for a fuel cell electrode. The combination of nickel oxide, silver oxide and ammonium bicarbonate powders is used to produce the electrode. The main role of silver element is to increase the activity in the electrode. Ni–Ag electrode can be used in fuel cells as positive and negative electrodes. All powders are mixed in the benzene solution by a magnetic mixer and then compressed to form green electrode. The range of pressure in this step is between 40 and 160 MPa. The green electrode is sintered in hydrogen atmosphere through a tube furnace and then cooled to 200 °C under argon atmosphere. The range of sintering temperature and time is 500–800 °C and 10–60 min, respectively. Also, silver oxide and ammonium bicarbonate percentages are varied from 20 to 65 and 15 to 35%, respectively. All parameters including composition, pressure, sintering temperature and time are changed during electrode fabrication to achieve optimised properties in the electrode. So, it is necessary to perform several tests measuring porosity, surface area, density, weight loss, mechanical strength, shrinkage, exchange current density and metallographic photos. The optimum conditions of the electrode production resulting from this investigation include compacting pressure 60 MPa, sintering temperature 560 °C, sintering time 15 min, silver oxide percentage 50% and ammonium bicarbonate percentage 27%.

Key findings

• ▸Optimal pressure range for green electrode formation is between 40-80 MPa.
• ▸Sintering temperature and time of 600-700 °C and 20-30 min, respectively, yield optimal electrode properties.
• ▸Composition of 40-50% silver oxide and 20-25% ammonium bicarbonate results in optimal electrode performance.

Keywords

Identifiers

DOI

10.1002/fuce.200600027

Journal

Fuel Cells

Year

2007