Vince L. Sprenkle

Optimized Lanthanum Ferrite-Based Cathodes for Anode-Supported SOFCs

Three cathode compositions (La0.8Sr0.2FeO3-d, La0.7Sr0.3Fe0.8Ni0.2O3-d and LaNi0.6Fe0.4O3-d) have been tested as SOFC cathodes at operating temperatures from 650 degrees C to 750 degrees C. Sintering temperatures were established for each cathode composition to provide optimized cell performance. La0.8Sr0.2FeO3-d exhibited the highest power density (> 900 mW/cm2 at 750 degrees C and 0.7 V), and indicated excellent performance stability over a 300 hour period.

Effects of chrome contamination on the performance of La0.6Sr0.4Co0.2Fe0.8O3 cathode used in solid oxide fuel cells

Chrome poisoning effects of various Cr-containing metal sources on the electrochemical performance of the La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF6428) cathode have been investigated. It was found that chromia-forming metals caused significant fade in power density due to the chrome poisoning, while alumina-forming alloys exhibited no influence on the cell degradation. This degradation caused by the chrome poisoning was accelerated at higher operating temperatures. Microstructural analysis conducted on the cells tested with chromia formers exhibited the formation of a strontium chromate phase in the entire cathode, leading to the homogeneous distribution of Cr in the cathode. Although the Mn-containing chromia former such as Crofer22 formed a continuous layer of the Cr-Mn oxide scale on the mesh surface, it was not effective enough to prevent Cr poisoning of the cathode. In contrast, alumina formers such as Haynes214 and Kanthal formed a continuous layer of the alumina scale, resulting in no Cr contamination in the LSCF6428 cathode.

Aqua-vanadyl ion interaction with Nafion ® membranes

Lack of comprehensive understanding about the interactions between Nafion membrane and battery electrolytes prevents the straightforward tailoring of optimal materials for redox flow battery applications. In this work, we analyzed the interaction between aqua-vanadyl cation and sulfonic sites within the pores of Nafion membranes using combined theoretical and experimental X-ray spectroscopic methods. Molecular level interactions namely solvent share and contact pair mechanisms are discussed based on Vanadium and Sulfur K-edge spectroscopic analysis.