Reduced graphene oxide for Li-air batteries: The effect of oxidation time and reduction conditions for graphene oxide
2015 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 85, 233-244 p.Article in journal (Refereed) Published
Reduced graphene oxide (rGO) has shown great promise as an air-cathode for Liâ€“air batteries with high capacity. In this article we demonstrate how the oxidation time of graphene oxide (GO) affects the ratio of different functional groups and how trends of these in GO are extended to chemically and thermally reduced GO. We investigate how differences in functional groups and synthesis may affect the performance of Liâ€“O2 batteries. The oxidation timescale of the GO was varied between 30min and 3days before reduction. Powder X-ray diffraction, micro-Raman, FE-SEM, BET analysis, and XPS were used to characterize the GOâ€™s and rGOâ€™s. Selected samples of GO and rGO were analyzed by solid state 13C MAS NMR. These methods highlighted the difference between the two types of rGOâ€™s, and XPS indicated how the chemical trends in GO are extended to rGO. A comparison between XPS and 13C MAS NMR showed that both techniques can enhance the structural understanding of rGO. Different rGO cathodes were tested in Liâ€“O2 batteries which revealed a difference in overpotentials and discharge capacities for the different rGOâ€™s. We report the highest Liâ€“O2 battery discharge capacity recorded of approximately 60,000mAh/gcarbon achieved with a thermally reduced GO cathode.
Place, publisher, year, edition, pages
2015. Vol. 85, 233-244 p.
IdentifiersURN: urn:nbn:se:uu:diva-242925DOI: 10.1016/j.carbon.2014.12.104ISI: 000349724700026OAI: oai:DiVA.org:uu-242925DiVA: diva2:785416