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Programmable Nanocomposite Membranes for Ion-Based Electrical Energy Storage

Spoerke, Erik D.; Small, Leo J.; Vandelinder, Virginia A.; Rempe, Susan; Wheeler, David R.; Bachand, George B.; Brumbach, Michael T.; McKenzie, Bonnie B.

This report describes a new, bio-inspired approach to electrical energy storage, based on the generation, maintenance, and discharge of ion concentration gradients. This approach was investigated as part of a Laboratory Directed Research and Development program at Sandia National Laboratories in Albuquerque, NM between October 2012 and September 2015. In particular, this report describes the development of ion-selective nanoporous membranes, controlled through pore morphology and Sandia-developed electrochemical functionalization. In addition, it describes a potential avenue to functionalize synthetic polymer membranes in a way that facilitates oriented ion pump binding to polymer surfaces. Finally, it highlights a number of new computational findings central to the understanding and ultimate design of synthetic ion channels and ion gates needed for biomimetic ion-based electrochemical energy storage.

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TYPE SAND Report YEAR 2016
DOIOSTI

Transformation of amorphous TiO2 to a hydronium oxofluorotitanate and applications as an HF sensor

Sensors and Actuators. B, Chemical

Appelhans, Leah A.; Finnegan, Patrick S.; Massey, Lee T.; Luk, Ting S.; Rodriguez, Mark A.; Brumbach, Michael T.; McKenzie, Bonnie B.; Craven, Julia M.

We examined amorphous titania thin films for use as the active material in a polarimetry based HF sensor. The amorphous titania films were found to be sensitive to vapor phase HF and the reaction product was identified as a hydronium oxofluorotitanate phase, which has previously only been synthesized in aqueous solution. The extent of reaction varied both with vapor phase HF concentration, relative humidity, and the exposure time. HF concentrations as low as 1 ppm could be detected for exposure times of 120 h.

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TYPE Journal Article YEAR 2015
DOIOSTI

Spectroscopic investigations of band offsets of MgO|AlxGa1-xN epitaxial heterostructures with varying AlN content

Applied Physics Letters

Paisley, Elizabeth A.; Brumbach, Michael T.; Allerman, A.A.; Atcitty, Stanley A.; Baca, A.G.; Armstrong, Andrew A.; Kaplar, Robert K.; Ihlefeld, Jon I.

Epitaxial (111) MgO films were prepared on (0001) AlxGa1-xN via molecular-beam epitaxy for x=0 to x=0.67. Valence band offsets of MgO to AlxGa1-xN were measured using X-ray photoelectron spectroscopy as 1.65±0.07eV, 1.36±0.05eV, and 1.05±0.09eV for x=0, 0.28, and 0.67, respectively. This yielded conduction band offsets of 2.75eV, 2.39eV, and 1.63eV for x=0, 0.28, and 0.67, respectively. All band offsets measured between MgO and AlxGa1-xN provide a>1eV barrier height to the semiconductor.

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TYPE Journal Article YEAR 2015
DOIOSTIScopusDOIOSTIScopus

Thermal transport in tantalum oxide films for memristive applications

Applied Physics Letters

Landon, Colin D.; Ihlefeld, Jon I.; Brumbach, Michael T.; Marinella, Matthew J.; Laros, James H.; Laros, James H.; Brennecka, Geoffrey L.

The thermal conductivity of amorphous TaOx memristive films having variable oxygen content is measured using time domain thermoreflectance. Thermal transport is described by a two-part model where the electrical contribution is quantified via the Wiedemann-Franz relation and the vibrational contribution by the minimum thermal conductivity limit for amorphous solids. The vibrational contribution remains constant near 0.9 W/mK regardless of oxygen concentration, while the electrical contribution varies from 0 to 3.3 W/mK. Thus, the dominant thermal carrier in TaOx switches between vibrations and charge carriers and is controllable either by oxygen content during deposition, or dynamically by field-induced charge state migration.

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TYPE Journal Article YEAR 2015
DOIOSTIScopus
Results 51–75 of 170
Results 51–75 of 170