With the development of solid oxide fuel cells (SOFCs) that operate in the intermediate temperature range of 650-800°C, ferritic stainless steels have become promising candidate materials for interconnects in SOFC stacks. The SOFC interconnect requires that the alloy possess not only excellent surface stability, but also high electrical conductivity through the oxide scale that forms at elevated temperatures and contributes to the alloy’s surface stability. It appears that ferritic Fe-Cr-Mn alloys may be potential candidates due to the formation of an electrically conductive scale containing <mml:math display="inline"><mml:mo stretchy="false">(</mml:mo><mml:mi mathvariant="normal">Mn</mml:mi><mml:mo>,</mml:mo><mml:mi mathvariant="normal">Cr</mml:mi><mml:msub><mml:mo stretchy="false">)</mml:mo><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mo>O</mml:mo><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:math>(Mn,Cr)3O4 spinel. To improve the understanding of scale growth on manganese-containing ferritic stainless steels and evaluate their suitability for use in SOFC interconnects, the oxidation behavior (i.e., growth kinetics, composition, and structure of the oxide scale) and the scale electrical conductivity of a commercially available Fe-Cr-Mn steel developed specifically for SOFC applications were investigated. The results are reported and compared with those of conventional ferritic stainless steel compositions. © 2004 The Electrochemical Society. All rights reserved.

Electrochemically active LiMnPO₄ nanoplates at lithiated/delithiated state were subjected to thermal stability and phase transformation evaluations for safety as a cathode material for Li-ion batteries. The phase transformation and oxygen evolution temperature of delithiated MnPO₄ were characterized using in situ hot-stage X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric-differential scanning calorimetry-mass spectroscopy (TGA-DSC-MS), transmission electron microscopy and scanning electron microscopy (SEM)-energy dispersive X-ray analysis (EDAX).

High-temperature electrochemical devices operate via an ion gradient that develops across a solid electrolyte. Consequently, hermeticity across this membrane is paramount. Not only must the electrolyte contain no interconnected porosity, but it must be connected to device chassis with a gas-tight seal. Here we report a new method of brazing developed specifically for solid-state electrochemical applications. We demonstrate that the seal is hermetic and resistant to thermal aging, can be thermally cycled under rapid heating rates with no measurable loss in seal strength, and has shown promise in sealing full-size planar solid oxide fuel cell (pSOFC) components. © 2005 The Electrochemical Society. All rights reserved.