@article {65, title = {Catalyst and electrolyte synergy in Li-O2 batteries}, journal = {Phys Chem Chem PhysPhys Chem Chem Phys}, volume = {16}, number = {7}, year = {2014}, note = {Gittleson, Forrest S
Sekol, Ryan C
Doubek, Gustavo
Linardi, Marcelo
Taylor, Andre D
eng
England
2014/01/11 06:00
Phys Chem Chem Phys. 2014 Feb 21;16(7):3230-7. doi: 10.1039/c3cp54555e. Epub 2014 Jan 10.}, month = {Feb 21}, pages = {3230-7}, abstract = {

Understanding the interactions between catalyst and electrolyte in Li-O2 systems is crucial to improving capacities, efficiencies, and cycle life. In this study, supported noble metal catalysts Pt/C, Pd/C, and Au/C were paired with popular Li-O2 electrolyte solvents dimethoxyethane (DME), tetraglyme (TEGDME), and dimethyl sulfoxide (DMSO). The effects of these combinations on stability, kinetics, and activity were assessed. We show evidence of a synergistic effect between Pt and Pd catalysts and a DMSO-based electrolyte which enhances the kinetics of oxygen reduction and evolution reactions. DME and TEGDME are more prone to decomposition and less kinetically favorable for oxygen reduction and evolution than DMSO. While the order of oxygen reduction onset potentials with each catalyst was found to be consistent across electrolyte (Pd \> Pt \> Au), larger overpotentials with DME and TEGDME, and negative shifts in onset after only five cycles favor the stability of a DMSO electrolyte. Full cell cycling experiments confirm that catalyst-DMSO combinations produce up to 9 times higher discharge capacities than the same with TEGDME after 20 cycles ( approximately 707.4 vs. 78.8 mA h g(-1) with Pd/C). Ex situ EDS and in situ EIS analyses of resistive species in the cathode suggest that improvements in capacity with DMSO are due to a combination of greater electrolyte conductivity and catalyst synergies. Our findings demonstrate that co-selection of catalyst and electrolyte is necessary to exploit chemical synergies and improve the performance of Li-O2 cells.

}, isbn = {1463-9084 (Electronic)
1463-9076 (Linking)}, doi = {10.1039/C3CP54555E}, author = {Gittleson, F. S. and Sekol, R. C. and Doubek, G. and Linardi, M. and Taylor, A. D.} } @article {81, title = {Bulk metallic glass micro fuel cell}, journal = {SmallSmall}, volume = {9}, number = {12}, year = {2013}, note = {Sekol, Ryan C
Kumar, Golden
Carmo, Marcelo
Gittleson, Forrest
Hardesty-Dyck, Nathan
Mukherjee, Sundeep
Schroers, Jan
Taylor, Andre D
eng
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
Germany
2012/11/28 06:00
Small. 2013 Jun 24;9(12):2081-5, 2026. doi: 10.1002/smll.201201647. Epub 2012 Nov 26.}, month = {Jun 24}, pages = {2081-5, 2026}, isbn = {1613-6829 (Electronic)
1613-6810 (Linking)}, doi = {10.1002/smll.201201647}, author = {Sekol, R. C. and Kumar, G. and Carmo, M. and Gittleson, F. and Hardesty-Dyck, N. and Mukherjee, S. and Schroers, J. and Taylor, A. D.} } @article {77, title = {Realizing comparable oxidative and cytotoxic potential of single- and multiwalled carbon nanotubes through annealing}, journal = {Environ Sci TechnolEnviron Sci Technol}, volume = {47}, number = {15}, year = {2013}, note = {Pasquini, Leanne M
Sekol, Ryan C
Taylor, Andre D
Pfefferle, Lisa D
Zimmerman, Julie B
eng
Comparative Study
Research Support, Non-U.S. Gov{\textquoteright}t
2013/06/28 06:00
Environ Sci Technol. 2013 Aug 6;47(15):8775-83. doi: 10.1021/es401786s. Epub 2013 Jul 26.}, month = {Aug 6}, pages = {8775-83}, abstract = {

The potential applications as well as the environmental and human health implications of carbon nanomaterials are well represented in the literature. There has been a recent focus on how specific physicochemical properties influence carbon nanotube (CNT) function as well as cytotoxicity. The ultimate goal is a better understanding of the causal relationship between fundamental physiochemical properties and cytotoxic mechanism in order to both advance functional design and to minimize unintended consequences of CNTs. This study provides characterization data on a series of multiwalled carbon nanotubes (MWNTs) that underwent acid treatment followed by annealing at increasing temperatures, ranging from 400 to 900 degrees C. These results show that MWNTs can be imparted with the same toxicity as single-walled carbon nanotubes (SWNTs) by acid treatment and annealing. Further, we were able to correlate this toxicity to the chemical reactivity of the MWNT suggesting that it is a chemical rather than physical hazard. This informs the design of MWNT to be less hazardous or enables their implementation in antimicrobial applications. Given the reduced cost and ready dispersivity of MWNTs as compared to SWNTs, there is a significant opportunity to pursue the use of MWNTs in novel applications previously thought reserved for SWNTs.

}, keywords = {*Hot Temperature, Cell Survival/*drug effects, Electrochemical Techniques, Glutathione/metabolism, Nanotubes, Carbon/*toxicity, Oxidation-Reduction, Photoelectron Spectroscopy}, isbn = {1520-5851 (Electronic)
0013-936X (Linking)}, doi = {10.1021/es401786s}, author = {Pasquini, L. M. and Sekol, R. C. and Taylor, A. D. and Pfefferle, L. D. and Zimmerman, J. B.} } @article {69, title = {Scalable fabrication of multifunctional freestanding carbon nanotube/polymer composite thin films for energy conversion}, journal = {ACS NanoACS Nano}, volume = {6}, number = {2}, year = {2012}, note = {Li, Xiaokai
Gittleson, Forrest
Carmo, Marcelo
Sekol, Ryan C
Taylor, Andre D
eng
Research Support, Non-U.S. Gov{\textquoteright}t
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2012/01/13 06:00
ACS Nano. 2012 Feb 28;6(2):1347-56. doi: 10.1021/nn2041544. Epub 2012 Jan 24.}, month = {Feb 28}, pages = {1347-56}, abstract = {Translating the unique properties of individual single-walled carbon nanotubes (SWNTs) to the macroscale while simultaneously incorporating additional functionalities into composites has been stymied by inadequate assembly methods. Here we describe a technique for developing multifunctional SWNT/polymer composite thin films that provides a fundamental engineering basis to bridge the gap between their nano- and macroscale properties. Selected polymers are infiltrated into a Mayer rod coated conductive SWNT network to fabricate solar cell transparent conductive electrodes (TCEs), fuel cell membrane electrode assemblies (MEAs), and lithium ion battery electrodes. Our TCEs have an outstanding optoelectronic figure of merit sigma(dc)/sigma(ac) of 19.4 and roughness of 3.8 nm yet are also mechanically robust enough to withstand delamination, a step toward scratch resistance necessary for flexible electronics. Our MEAs show platinum utilization as high as 1550 mW/mg(Pt), demonstrating our technique{\textquoteright}s ability to integrate ionic conductivity of the polymer with electrical conductivity of the SWNTs at the Pt surface. Our battery anodes, which show reversible capacity of approximately 850 mAh/g after 15 cycles, demonstrate the integration of electrode and separator to simplify device architecture and decrease overall weight. Each of these applications demonstrates our technique{\textquoteright}s ability to maintain the conductivity of SWNT networks and their dispersion within a polymer matrix while concurrently optimizing key complementary properties of the composite. Here, we lay the foundation for the assembly of nanotubes and nanostructured components (rods, wires, particles, etc.) into macroscopic multifunctional materials using a low-cost and scalable solution-based processing technique.}, isbn = {1936-086X (Electronic)
1936-0851 (Linking)}, author = {Li, X. and Gittleson, F. and Carmo, M. and Sekol, R. C. and Taylor, A. D.} } @article {61, title = {Bulk metallic glass nanowire architecture for electrochemical applications}, journal = {ACS NanoACS Nano}, volume = {5}, number = {4}, year = {2011}, note = {Carmo, Marcelo
Sekol, Ryan C
Ding, Shiyan
Kumar, Golden
Schroers, Jan
Taylor, Andre D
eng
2011/03/05 06:00
ACS Nano. 2011 Apr 26;5(4):2979-83. doi: 10.1021/nn200033c. Epub 2011 Mar 3.}, month = {Apr 26}, pages = {2979-83}, abstract = {Electrochemical devices have the potential to pose powerful solutions in addressing rising energy demands and counteracting environmental problems. However, currently, these devices suffer from meager performance due to poor efficiency and durability of the catalysts. These suboptimal characteristics have hampered widespread commercialization. Here we report on Pt(57.5)Cu(14.7)Ni(5.3)P(22.5) bulk metallic glass (Pt-BMG) nanowires, whose novel architecture and outstanding durability circumvent the performance problems of electrochemical devices. We fabricate Pt-BMG nanowires using a facile and scalable nanoimprinting approach to create dealloyed high surface area nanowire catalysts with high conductivity and activity for methanol and ethanol oxidation. After 1000 cycles, these nanowires maintain 96\% of their performance-2.4 times as much as conventional Pt/C catalysts. Their properties make them ideal candidates for widespread commercial use such as for energy conversion/storage and sensors.}, isbn = {1936-086X (Electronic)
1936-0851 (Linking)}, author = {Carmo, M. and Sekol, R. C. and Ding, S. and Kumar, G. and Schroers, J. and Taylor, A. D.} }