Cool fuel cells open application possibilitiesPublished on August 18th, 2008 | By: email@example.com
Science also contains a report from researchers in Spain who have developed a new electrolyte that allows a solid oxide fuel cell to operate at temperatures hundreds of degrees lower than those of conventional electrolytes – a development they say could boost the practicality of SOFCs. Led by Jacobo Santamaria, of the applied-physics department at the Universidad Complutense de Madrid in Spain, the research team reports it modified a yttria-stabilized zirconia-strontium-titanium electrolyte, enabling it to work well below the current SOFC 700ºC operating temperature. Santamaria’s prototype is able to operate at 84ºC. Santamaria’s team found that ionic conductivity at low temperatures can be significantly improved by combining layers of standard electrolyte materials with 10-nm-thick layers of strontium titanate. When the two materials are combined, because of differences in their crystal structures, vacancies occur in areas that normally host oxygen atoms. These vacancies create pathways that enable oxygen ions to move through the material, improving its conductivity at room temperature by a factor of 100 million, the researchers learned. Santamaria cautioned that the newly developed electrolyte is not yet ready to integrate into commercial fuel cells. He says his team’s discovery requires further verification, particularly in light of the difficulty of measuring extremely thin materials’ performance. The researcher also noted that the direction of improved conductivity – along the electrolyte material’s plane rather than perpendicular to it – would require a redesign of today’s fuel cells, including improvements to fuel-cell electrode materials.
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