FY2010 - Oak Ridge National Laboratory

Laboratory-Wide Fellowships—
Weinberg Fellowship
Results and Accomplishments
The primary objective for the 2010 fiscal year was to develop vapor deposition techniques to synthesize
thin film cathodes composed of 9,10-anthraquinone (9,10-AQ). A significant accomplishment was the
development of a vacuum evaporation system to enable the deposition of 9,10-AQ. Much effort was
required to optimize the system because 9,10-AQ has a low vapor pressure and high boiling point of
380°C, which makes controlled evaporation difficult. Currently, 9,10-AQ can be successfully deposited
into crystalline structures. Also, the solubility of 9,10-AQ in organic solvents was studied; these data
were not readily available in the literature. Understanding the organic solubility enabled the fabrication of
traditional composite cathodes by slurry techniques. The composite cathodes consisted of 9,10-AQ as
active material, carbon black, and binder. Now that these cathodes have been successfully fabricated, the
performance of 9,10-AQ in a standard battery cell with a lithium anode and organic liquid electrolyte can
be characterized. These results will be readily utilized by other researchers working on novel cathodes.
Currently, the two remaining tasks of characterizing the electrochemical performance of 9,10-AQ and
correlating structural parameters of 9,10-AQ to its performance have not been completed. Although
9,10-AQ can be vapor deposited, its resulting structure, consisting of needle-like crystallites, precludes
electrochemical characterization. Future work will focus on modulating the deposition parameters to
achieve smooth, continuous films of 9,10-AQ that are appropriate for characterization and then
understanding how the structural parameters of the films influence performance.
05921
An Investigation into the Synthesis and Annealing of Iron-Based
Superconductors under High Magnetic Fields
Orlando Rios, Athena Safa-Sefat, Gail M. Ludtka, and Michael A. McGuire
Project Description
The state of the art in synthesis and processing of class II superconductors has recently made significant
advances; however, there have been limited yet promising studies on processing of these materials under
extreme conditions, specifically high magnetic fields. The current study investigates the structure,
microstructure, and interrelated electrical properties of iron-based superconductors, reaction sintered
and/or annealed, under high magnetic fields with the aim of increasing the critical current density at or
below the critical transition temperature. It has been well established that magnetic ordering is deeply
rooted in the underlying mechanism behind high-temperature superconductivity; therefore, it is expected
that the synergistic action of the high magnetic fields and thermal energy will facilitate the growth of
crystals that exhibit improved magnetic order below the critical temperature T c (for superconductors) or
Neel temperature (for antiferromagnets). Of the known high-temperature superconductors, the iron-based
pnictide class of materials should most strongly respond to magnetic processing due to the strong
magnetic properties of the iron atom electronic structure.
Mission Relevance
Historically, superconductors are key energy materials that are important to the DOE mission and national
security. A fundamental understanding of the underlying mechanisms behind superconductivity and how
the material properties are affected by the synthesis and processing conditions are vital to the design of
the next generation of materials. The current study investigates a relatively unexplored process variable
(magnetic fields) that is state of the art in industrially transferable technologies. The results of this study
are expected to help establish ORNL’s expertise in the advanced high magnetic field processing and
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