Showing papers by "Edward J. Plichta published in 2009"
TL;DR: In this paper, the intimate role of electrolyte, in particular the role of ion conducting salts, in determining the reversibility and kinetics of oxygen reduction in nonaqueous electrolytes designed for such applications is reported.
Abstract: Unlocking the true energy capabilities of the lithium metal negative electrode in a lithium battery has until now been limited by the low capacity intercalation and conversion reactions at the positive electrodes. Abraham et al. (Abraham, K. M.; Jiang, Z. J. Electrochem. Soc. 1996, 143, 1−5) overcame this limitation by removing these electrodes and allowing lithium to react directly with oxygen in the atmosphere, forming the Li-air battery. The Li/O2 battery redox couple has a theoretical specific energy of 5200 W h/kg and represents the ultimate, environmentally friendly electrochemical power source. In this work, we report for the first time the intimate role of electrolyte, in particular the role of ion conducting salts, in determining the reversibility and kinetics of oxygen reduction in nonaqueous electrolytes designed for such applications. Such fundamental understanding of this high energy density battery is crucial to harnessing its full energy potential. The kinetics and mechanisms of O2 reductio...
621 citations
TL;DR: In this article, a detailed study of the kinetics of oxidation of ferrocene to ferrocenium ion was carried out using cyclic (CV) and rotating disk electrode (RDE) voltammetry.
96 citations
TL;DR: In this article, a buckypaper-supported platinum (Pt) catalysts derived from carbon nanotube and carbon nanofiber have demonstrated a high Pt utilization in proton exchange membrane fuel cells.
Abstract: Due to their unique microstructure, buckypaper-supported platinum (Pt) catalysts derived from carbon nanotube and carbon nanofiber have demonstrated a high Pt utilization in proton exchange membrane fuel cells (PEMFCs). [SWNT means single-walled carbon nanotube.] The durability of a buckypaper-supported Pt catalyst was investigated using an accelerated degradation test (ADT) in a mimic cathode environment of PEMFC. Compared to commercial carbon black-supported Pt, Pt/buckypaper showed a better catalyst durability after holding at 1.2 V for 400 h; specifically, almost 80% of the Pt electrochemical surface area was lost for Pt/carbon black, with only a 43% loss for Pt/buckypaper. Transmission electron microscopy and cyclic voltammetry were used to study the Pt degradation mechanism. It was concluded that Pt coarsening and Pt detachment from buckypaper support due to carbon corrosion make the major contribution to the Pt surface area loss under this condition. The Pt loss via detachment from supports after the ADT was calculated as 18% in Pt/buckypaper, while the Pt loss was 69% in Pt/C. It is supposedly due to the higher corrosion resistance of buckypaper because of its high graphitization degree, which is indicated by a slower formation rate of surface oxides in buckypaper than in carbon black. Further durability improvement of the Pt/buckypaper is expected by improving the dispersion of Pt on the buckypaper to reduce Pt sintering.
36 citations