The pressure to develop cleaner, more efficient single sources of heat and electrical energy is the driving force behind the development of solid oxide fuel cells (SOFCs) at NRC and elsewhere. However, if SOFCs are to become commercially viable, production costs must be lower and the reliability, as well as durability of these systems needs improvement.

NRC Institute for Chemical Process and Environmental Technology (NRC-ICPET) researchers, Drs. Pamela Whitfield, Gisele Amow and Isobel Davidson, teamed up with Dr. Stephen Skinner (Department of Materials, Imperial College, U.K.) to collaborate on a project that tackled these challenges.

The research was funded by the NRC-British Council Joint S&T Fund and involved comparing methods to synthesize novel cathode materials using a conventional Pechini process and a non-conventional production method - microwave-assisted synthesis. The novel cathode materials produced by both methods were then evaluated for their potential use in intermediate temperature SOFCs.

The two teams worked together on developing new cathode compositions in a family of oxides known to be hyperstoichiometric in oxygen. In this class of materials the ionic transport of oxygen is augmented by interstitial oxide ions within the structure's crystal lattice. Led by Dr. Skinner, the British team provided expertise on measuring oxide ion mobility using a technique of isotopic exchange and secondary ion mass spectroscopy. The research led to new cathode compositions with greater ionic conductivity, thereby decreasing the amount of energy necessary for oxygen ion mobility and enabling the fuel cell to operate at lower temperatures. Lower operating temperatures can increase the durability of SOFCs and makes smaller-scale applications, such as portable power units, more feasible.

On the cathode production side, NRC-ICPET's project team explored a novel production method - microwaves - to enhance the speed and lower the temperatures at which cathode materials are synthesized. This helps to lower the production costs associated with these materials. Microwave synthesis provides additional advantages as well. Because of the unique way that microwaves interact with inorganic materials, this method of synthesizing materials can provide new material compositions with unusual crystal structures and morphologies that may actually help to improve cell performance.



Posted by: Kevin    Source