Crack Healing in Glass and Glass - Ceramic Composite for Solid Oxide Fuel Cells

Abstract

Demand for energy consumption is ever increasing. The rapid urbanization has facilitated access to power and transportation to a vast majority of population. To maintain current demand and fulfill the future need alternative methods of power generation with highest efficiency is necessary to avoid negative impact of excessive use of fossil fuels. One such alternative technology is solid oxide fuel cell (SOFC). However, one of the major limitations in the development of solid oxide fuel cell’s long term operation, under thermal cycle and high stack load, is the fabrication of a stable sealant which can maintain the hermeticity of the stack and avoid electrical shorting of the cell component. Sealant made out of glass are preferred since it offers inertness, ability to tailor the coefficient of thermal expansion (CTE) to match with other cell components, interfacial stability, high electrical resistance and wettability with the adjoining surface to maintain the stacks hermeticity over a prolonged operation. However, glass and glass ceramics are susceptible to cracking due to their brittle nature when the fuel cell is under thermal transient or even due to slight CTE mismatch with other cell components. This issue can be addressed if the glass maintains its vitreous property thereby facilitating crack healing at cell operating temperature. The effect of temperature, time and composition on crack healing kinetics in glass and glass-ceramics will be discussed and presented.