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Reversibility of Noble Metal-Catalyzed Aprotic Li-O2 Batteries.
- Source :
-
Nano Letters . Dec2015, Vol. 15 Issue 12, p8084-8090. 7p. - Publication Year :
- 2015
-
Abstract
- The aprotic Li-O2 battery has attracted a great deal of interest because, theoretically, it can store far more energy than today's batteries. Toward unlocking the energy capabilities of this neotype energy storage system, noble metal-catalyzed high surface area carbon materials have been widely used as the O2 cathodes, and some of them exhibit excellent electrochemical performances in terms of round-trip efficiency and cycle life. However, whether these outstanding electrochemical performances are backed by the reversible formation/decomposition of Li2O2, i.e., the desired Li-O2 electrochemistry, remains unclear due to a lack of quantitative assays for the Li-O2 cells. Here, noble metal (Ru and Pd)-catalyzed carbon nanotube (CNT) fabrics, prepared by magnetron sputtering, have been used as the O2 cathode in aprotic Li-O2 batteries. The catalyzed Li-O2 cells exhibited considerably high round-trip efficiency and prolonged cycle life, which could match or even surpass some of the best literature results. However, a combined analysis using differential electrochemical mass spectrometry and Fourier transform infrared spectroscopy, revealed that these catalyzed Li-O2 cells (particularly those based on Pd-CNT cathodes) did not work according to the desired Li-O2 electrochemistry. Instead the presence of noble metal catalysts impaired the cells' reversibility, as evidenced by the decreased O2 recovery efficiency (the ratio of the amount of O2 evolved during recharge/that consumed in the preceding discharge) coupled with increased CO2 evolution during charging. The results reported here provide new insights into the O2 electrochemistry in the aprotic Li-O2 batteries containing noble metal catalysts and exemplified the importance of the quantitative assays for the Li-O2 reactions in the course of pursuing truly rechargeable Li-O2 batteries. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15306984
- Volume :
- 15
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Nano Letters
- Publication Type :
- Academic Journal
- Accession number :
- 113302385
- Full Text :
- https://doi.org/10.1021/acs.nanolett.5b03510